Datasets:

Hieuman

/

en_HRS_11_22_24

like 0

[ [ "Pantyhose Potato Heads\nIntroduction: Pantyhose Potato Heads\nI'm old enough to remember the original <PERSON>. There was no plastic potato with strategically-placed holes where you could insert the blunt plastic rods that held facial features. Instead, you borrowed a potato from the kitchen and impaled sharp spikes into it to hold the eyes and mouth in place.\nThe potato heads in this Instructable are neither hard plastic nor real spuds. They are tubes cut from pantyhose, stuffed with fiberfill, and stitched to create facial features.\nSupplies\nA pair of pantyhose - One pair of Queen Size can make 4-6 potato heads\nSewing thread - for average shade- s darker hose might need darker thread\nSewing needle - I used a curved quilting needle\nScissors\nFiberfill - for filling the pantyhose segment. I used repurposed fluff from the unused sections of the stuffed plush animals I used to make my Frankenstuffed Feejee Mermaid.\nOPTIONAL - doll eye buttons, rouge for cheeks and shading\nStep 1: The First Cut Is the Deepest\nLay out the pantyhose and cut off the heavier toe section.\nMake another cut 6-8 inches along the leg, and tie one end, as close to the end of the segment as possible.\nStep 2: Get Stuffed!\nStart stuffing fiberfill into the pantyhose section , more and more, until it's semi-firm.\nTie off the open end.\nWEIRD IDEA\nIf you want to make your potato head as a shrunken head, you could leave the extra hose attached for hanging.\nStep 3: The Great Cover-Up\nStitch a circle around the knot where you tied off the pantyhose.\nPress the knot into the fiberfill and tighten the circle until it narrows and closes up over the knot, so it doesn't stick out. Tie off the thread.\nRepeat the procedure to cover the other knot.\nStep 4: The Eyes Have It\nPotatoes are lumpy, and they have the \"eyes\" where new potato plants sprout. To simulate this, randomly make small stitches and push the needle to other parts of your potato, tightening the thread as you go to make indentations in the surface.\nStep 5: The Nose Knows\nGather a lump of the fiberfill stuffing and sew a running stitch around the area, but do not tighten the thread as much as you did over the end knots. This will give you a nice lump of a nose.\nStep 6: Smile, Darn Ya', Smile!\nbring the needle out below and to the side of the nose, and stitch a curve going down and up to the other side of the nose. Tighten it, and you have a nice smile on the face.\nOF COURSE - If you want a grumpy potato head, stitch a curve going up and down to give the face a frown.\nStep 7: Here's Looking at You, Kid\nNow, it's time for the eyes.\nMETHOD 1 - Sew a running stitch in a teardrop pattern. Tighten it lightly.", "22" ], [ "Repeat for the other eye.\nMETHOD 2 - Knot the thread around the shank of a doll eye. Run the needle through the stuffing to the other side of the nose, and affix another eye.\nStep 8: \"Ear\" You Go!\nPinch a wad of stuffing through the fabric. Stitch tightly in a slight curve. Tie off, Run the needle through the fiberfill to the other side of the head, and repeat for the other ear.\nStep 9: There You Go!\nNow you have a Pantyhose Potato Head!\nHOWEVER - If you want, you can make garden-variety Pantyhose Potatoes. Follow the directions up through Step 4, and it will look like a potato, period. In fact, you could make a basket of \"potatoes,\" with one \"potato head\" as a surprise!\nStep 10: Don't Do This!\nThis was my first experimental Pantyhose Potato Head. I made a major mistake. I left the toe of the pantyhose as part of the head, and the darker fabric is very visible. Don't do this!\nI hope you enjoy this Instructable, and I hope you will give it a try and post your projects...but don't cut up your mother's best pantyhose!\nThis Instructable was made for the 2020 Potato Speed Challenge. Vote early and vote often!", "879" ], [ "Faux Snow Globe Gift Jars\nIntroduction: Faux Snow Globe Gift Jars\nI used to put Christmas treats in glass jars - candy, party mix, recipe fixings. People would ooh and ahh, eat the contents, and what did they have? An empty jar. They should be left with something worth keeping, something they could cherish.\nAHA!\nA Faux Snow Globe Jar! What this Instructable presents is a way to combine several of the crafts I make (Some are Instructables I have shared) and other techniques to make something that was a big hit at my Elves' Fanily Workshops at several libraries (the motto - \"Why should elves have all the fun?\").\nSupplies\n* Mason-type jar or any lidded glass jar. For this Instructable, I used a pint/2 cup/16-ounce jar. The Gallery samples are quart/4 cup/32-ounce jars\n* Clear shot glass, plastic tumbler, candle holder (The sample for the how-to uses a candle holder), or half of a plastic fillable ornament (The Gallery at the end uses half-dillables)\n* Cotton ball (a.k.a. Cotton Wool)\n* Candy, party mix, cereal, nuts, raisins, pretzel sticks, recipe ingredients, or anything you wish to put inside the gift jar\n* Hot glue gun and glue gun sticks\n* Ribbon\n* Decorations: pompon balls (1/2 inch: a pompon is a small fluff ball, a pompom is a large artillery cannon), small plastic figures or toys\n* Scissors\n* Measuring tape or ruler (to see how wide the lid is, and to measure possible globe toppers)\nSupplies for:\nTree\n* Green paper or construction paper, cut to a 3-inch square\nSnowman\n* 3 pompon balls\n* 2-inch piece of brown wire or a thin twig\n* Black and orange markers\n* Yarn\nSkier\n* Wire, plastic-insulated, 20-24 gauge\nStep 1: Making the Tree\nFor more complete instructions, follow the link to the Kirigami Christmas Tree in Green Instructable.\n* Take the 3-inch paper square (larger, if you have a larger snow globe cup) fold it on the two diagonals, turn it over, and fold it on the two medians. Collapse it to four triangular flaps.\n* F,or each flap, press it in along the fold to make it tlaplets. When each flap has been doubled, trim off the lower tails to leave a triangle.\n* Make two sets of cuts from the edge toward the center, but not all the way. (In the Instructable, using an 8.5-inch square, four sets of cuts are made. With a smaller square, four cuts would be too close)\n* For each of the lower cut segments, fold the upper outside corner until the fold touched as close to the bottom of the segment as possible. Repeat this with all the segments of each flaplet.\n* Fluff it out, stand it up, and you have a little tree!\nStep 2: Making the Snowman\n* Hot-glue two of the pompon balls together. Glue a two-inch piece of wire onto one end of the balls for arms.", "644" ], [ "Glue the third ball to the wire.\n* Using a black marker, make dots below the arms for coal buttons. Make dots above the arms for the mouth and eyes. Use an orange marker to make a dot for the carrot nose.\n* Take a short piece of yarn, unravel it , and separate one ply from the rest. tie it around the neck of the snowman as a scarf, and trim the ends to the length you think best. You now have a snowman!\nStep 3: Making the Skier\nFor more complete instructions, follow the link to the Wire Skier--a Suji Project Instructable. The dimensions here are smaller, because the space on a pint jar is less.\n* For the skeleton/armature/skis, fold a 16-inch piece of wire in half, and in half again. Fold a 16-inch wire in nearly half for the top and sleeves. Wrap the shorter half up 5 times around the four core wires. Fold down one core and wrap out the arm 10 times. Wrap the longer half up around the first set of wrappings 5 times. Fold down another core and wrap out that arm 10 times.\n* For the pants, fold another 16-inch wire in almost-half. Wrap the shorter half down the core 3 turns, divide the lower core into 2 groups of 2, and wrap out one leg 15 times.\n* Wrap the longer half down, around the first wraps, 3 times. Wrap the other leg 15 turns.", "879" ], [ "A Basic Guide to Bunny Hats\nIntroduction: A Basic Guide to Bunny Hats\nIn two whole years, ever since I got my rabbit, I have come to one important conclusion.\nNOTHING is cuter than a bunny. Well, except a bunny with a hat...\nIn this Instructable, I'll show you how to make easy bunny hats; designed with your rabbit's comfort and safety in mind.\nSupplies\nGet creative! There are thousands of yarn choices out there. Have fun choosing yarn that will complement your bunny's fur color. I mean, you could even use your own hair ties and scrunchies as bunny hats! Just make sure that whatever you're using is soft and light. You don't want to irritate your bunny, after all.\nThe materials I'll be using for these examples are:\n* Yarn, any color\n* Darning needle\n* Crochet hooks\n* Knitting needles\nStep 1: Who's Your Model?\nThis is <PERSON>, my three-year old lionhead bunny; aka <PERSON>. She likes head rubs and bananas, and is extremely patient and forgiving.\nTake your bunny's personality and bitty quirks into mind when designing your bunny hat. Would they be tolerant of something on their head, even for a short time? Test it out with a scrunchie. If your bunny absolutely despises it, maybe only give them the hat for a quick photoshoot :)\nStep 2: Two Types of Bunny Hats\nThe rule of thumb for bunny hats is \"The looser and lighter the better\". A good bunny hat should still allow free ear movement. It should never pinch. You need to be able to fit at least three fingers between the hat band and your bunny's ears.\nThat said, here are two types of bunny hats.\nThe Ideal Bunny Hat\nThis type of hat is what I like to call the ideal hat.", "673" ], [ "It's light, minimal, and as you can see, has plenty of space. I find that, because it's light, and interferes so little with <PERSON>'s natural ear movement, she barely notices it at all! Unless she shakes her fur, it can stay on for hours.\nThe Photoshoot Hat\nAlthough you can certainly use the simple bunny hats in a photoshoot, sometimes you just want to make a really, well, fancy hat for your bunny. Probably something beautiful, but not very practical. Some good examples would be this fascinator-inspired hat I made last year, or this hat with a big red bow. Both are nice, but I would only put them on <PERSON> for a short while, because eventually, it would just get annoying.\nStep 3: Creating an Ideal Bunny Hat\nMaking this kind of hat is as simple as:\n* Chain-measuring around your bunny's ears\n* Crocheting a thin band in the round\n* Creating cute mini flowers and/or leaves\n* Putting it all together\nStep 4: Creating a Photoshoot Hat\nMaking this kind of hat is slightly more complicated. Because they usually have bigger decorations, you might need to give it either a smaller diameter and/or a greater width. Just make sure you stick to the three finger limit. Personally, if I am making a wider headband, I like to knit in the round. It's stretchier than a crocheted headband, and is also more aesthetically pleasing. :)\nAside from that, just follow the basic steps above.\nStep 5: The End\nI have now imparted to ye the basic knowledge of bunny hats. How do you feel? Empowered? INSPIRED?\nGo forth and create!\nI have spoken.", "879" ], [ "Waste Paper Baskets From Real Waste Paper\nIntroduction: Waste Paper Baskets From Real Waste Paper\nOther boys grew up shooting baskets.\nI grew up weaving baskets.\nIn the 1990's, I learned a new way of basketmaking that recycled things others would throw away - Waste Paper Baskets! An online database at the library had an article on making baskets from rolled newspaper, and that was all I needed to start on a hobby that helps the environment.\nWhat do you need?\n* Newspaper - Lots of newspaper. A good-sized basket uses about 100 sheets of newspaper.\n* Glue. - I use non-toxic, clear glue sticks, rather than liquid glue. Hot glue doesn't dry flexible enough for the projects\n* Scissors - Used to trim rolls during the finishing process.\nOPTIONAL\n* Spray Acrylic (clear) or Shellac - Used to make a finished product shiny and waterproof.\n* Dowel or Skewer -An alternative method for rolling the paper.\nStep 1: Rolling, Rolling, Rolling\nTo start, lay out a sheet of newspaper so that a long edge is toward you. (If you want to use a dowel or skewer, lay it across a corner of the paper at about a 30-degree angle.) Begin rolling. As you roll, the angle will change, and one end of the roll will become fatter than the other end.\nAbout two inches before you reach the opposite corner from where you started, use the glue stick to coat the corner, then finish rolling. You now have a thin roll of paper that is narrower at one end.\nMake another roll...and another roll...and another...and another...and another and another and anotherandanotherandanotherand..... Basically, keep rolling paper until you run out of paper to roll.\nSome newspapers are better for rolling than others. My local paper used a plant-based ink that is smudge- resistant. With other newspapers, rolling a few sheets covered the hands with black ink, but the plant-based ink left a fraction of the mess.\nYou do not have to use newspaper. There are other options mentioned in the notes at the end of this Instructable.\nStep 2: Setting It Up\nI refer to the rolls of newspaper as \"reeds,\" because that's the craft material I used when I started making baskets almost 60 years ago. For a start, I use 8 reeds, divide them into two groups of four, and lay them out as a cross, an X, or a plus (+). They will become the spokes of the basket.\nNext, take two more reeds, and slide the narrow end of one a few inches into the wider end of the other, until it fits snugly.", "286" ], [ "This will be the method used to keep from running out of reed, creating a continuous weaving unit. Fold it in half, more or less. One end should be longer, so the joints between reeds will be staggered, not in the same places.\nStep 3: Twining Instead of Weaving\nIf this was a regular, woven basket, you would use one of the spoke-halves as the start of your in-and-out weaving, to give you an odd number of spokes. However the rolled-paper reed isn't as solid as regular reeds, so I recommend a different method: Twining - using two weavers twisted in a spiral.\n* Take the bent weaver and slide it over one section of the X-spokes.\n* Fold the lower section of the weaver up and over the upper half and the next section. Fold the lower part of the weaver across the bottom, then up and over. Follow that pattern of alternate overs until you have gone around the X two times.\nWhen you get near the end of a weaver, add another reed, If the end is a thin end, slide the thick end of the new reed over the ending reed. If the end is wider, insert the thin end of the the new reed into the wider old reed.\nStep 4: Dividing the Spokes\nNext, the X needs to be turned into an 8-pointed star. Instead of going across four spokes at a time, only go over two spokes before you twist. Continue twining double-spokes until you have completed at least. two rounds. After that, divide the spokes again and twine around single spokes.\nStep 5: Going Up\nWhen the base is wide enough for your basket (This demonstration basket was about 12 inches across), it's time to raise your sights and go up (unless you want a flat tray or placemat).\nThe easiest way to do this is to bend the spokes up. They have now, magically, become stakes. Continue the twisting of the twining stitch, going around and around the basket. At first.", "636" ], [ "Tunnel Bridge for Small Pets, <PERSON>\nIntroduction: Tunnel Bridge for Small Pets, <PERSON>\nThis tutorial will instruct you on how to make your Tunnel Bridge for small animals. Great for Sugar Gliders, Rats, Ferrets, Hedgehogs, Guinea Pigs & other small pets.\nThe tunnel makes a great place for your pet to play or sleep. Small animals like to climb, run through tunnels, and sleep. This design will do all of that.\nThe Tunnel Bridge for this instruction measures out as 8\" x 15\"\nYou can make this larger by adding a few inches to all sides or smaller by decreasing inches on all sides.\nI use C-Links to attach the Tunnel Bridge inside the cage.\nSupplies\nQuilters mat\nRotary Cutter\nQuilting ruler\nScissors\nSewing machine\nFleece Fabric\nStep 1: Gather and Cut\nCut all of your fabric out first.\nI use Fleece Fabric with all of my small pet projects. You could use a solid color or mix it up with prints and solids.\n* Two cuts of 9\" X 16\" of fleece fabric or (one 9\" X 16\" solid and one 9\" X 16\" matching print)\n* Two cuts of 10\" X 12\" of fleece fabric or (one 10\" X 12\" solid and one 10\" X 12\" matching print)\n* Four cuts of 1\" X 5\" strips.\n**The longer piece will be the bridge while the shorter piece will be your tunnel. **\nStep 2: Start to Assemble\nTake your 10' X 12\" pieces of the Tunnel putting the right sides together. Sew your tunnel together on the long side.\n(To determine which is the right side of the fabric, hold the fleece length way and lightly pull on the fabric. The edge will fold down towards the wrong side)\nStep 3: Connect the Tunnel to the Bridge\nTurn your Tunnel right side out.", "879" ], [ "Now lay one piece of the Bridge down right side up. Center the Tunnel's short side with the Center of the Bridge's long side. Make a small fold in the Tunnel so the other side of the Tunnel matches up with the other long side of the Bridge.\n(If you used solids and prints keep the prints together. When laying the print piece of the Bridge down, right side up, then lay the Tunnel short side on the Bridge, print side down).\nStep 4: Adding the 4 Straps\nTake each 1' X 5' strip, fold it in half right side out. Take 2 strips with the hoops facing inward on the short edge of the Bridge about 1\\2 inches from the long edge. Pin the other two strips on the opposite side of the Bridge the same way.\nStep 5: Finish the Bridge\nTake your last long Bridge piece and pin it down over the top, right side facing down.\nSew around the outer edges of the Bridge leaving an opening about 3 to 4 inches on one short side of the Bridge. Trim the corners after sewing so the Bridge will have nice flat corners when turned inside out.\nStep 6: Finish and Hang\nTurn the Bridge right side out through the hole you left on one end. Pull lightly on the tabs to straighten out the corners. Sew the open hole shut with your machine or hand needle.\nStep 7: Solid or Print?\nYou can turn the Tunnel inside out to change the look of your Bridge-Tunnel.", "163" ], [ "DIY Tailor's Ham Sewing Pressing Tool\nIntroduction: DIY Tailor's Ham Sewing Pressing Tool\nA tailor's ham is a tool used in sewing to help aid in pressing and shaping garments using heat and steam. You can use it to open up seams or shape fabric.\nA tailor’s ham or any other pressing tool needs to be able take the maximum amount of heat and steam your iron can push out. Most pressing tools will have two sides - one from a tightly woven smooth material and one from a tightly woven material with some texture.\nEach tool will have 2 layers on each side. The inner layer should be made from a\ntightly woven cotton fabric. Muslin works good for this. The outer layer has 2 sides. One side should be made from a tightly woven cotton. Quilting cottons work great for this. The other side is usually made from wool because it can grip onto fabrics. Cotton flannel also works good for this.\nFor stuffing, the traditional choice is sawdust. Fabric scraps, wool or cotton stuffing, or walnut pet bedding are all good alternatives. The goal is to stuff it very firmly!\nSupplies\nRECOMMENDED MATERIALS\n* 100% Cotton Muslin (Inner/Lining)\n* 100% Quilting Cotton, Tightly Woven Cotton Fabric, or Tightly Woven Linen Fabric (Outer)\n* 100% Wool Fabric or 100% Cotton Flannel (Outer)\n* Sawdust, cotton/wool stuffing, fabric scraps, or walnut pet bedding\n* PDF Tailors Ham Sewing Pattern\nThread Be sure to pre-wash and/or pre-shrink all fabrics and make sure there is no color bleeding from the chosen fabric.\nStep 1: Printing the Pattern\nTo print your pattern, open it in Adobe Acrobat. This is free software and can be downloaded from Adobe. Select the Print Icon or select File -> Print\nThe print dialog box will be displayed.\nIn the Page Sizing & Handling section of the Print Dialog, make sure the options below are selected.\nMake sure Actual Size is selected and Print on both sides of paper is not checked.\nStep 2: Assembling the Pattern\nPlace your two printouts side by side.\nCut away the inside edge from pattern piece where they intersect.\nAlign the pieces and tape together.\nCut out on the black outer line. The inner blue line marks the SEAM ALLOWANCE.\nStep 3: Making the Tailor's Ham - 1\nCUTTING THE INNER FABRIC\n1. Place your pattern on the fabric, aligning the grain, on a folded piece of fabric. 2.", "673" ], [ "Cut 2 copies of the pattern. Set aside.\nCUTTING OUTER FABRIC - COTTON SIDE\n1. Place your pattern on the fabric, aligning the grain, on a single layer of fabric, right side up.\n2. Cut 1 copy of the pattern. Set aside.\nCUTTING OUTER FABRIC - WOOL/FLANNEL\n1. Place your pattern on the fabric, aligning the grain, on a single layer of fabric, right side up.\n2. Cut 1 copy of the pattern. Set aside.\nStep 4: Making the Tailor’s Ham - 2\nASSEMBLY\n1. Place 1 layer of cotton muslin on your table.\n2. Place the quilting cotton layer on top of the muslin right side up, aligning the shapes.\n3. Place the wool layer right side down on top of the cotton layer, aligning the shapes.\n4. Place the last layer of muslin on top and align all shapes.\n5. Pin and mark a space to leave a gap large enough for turning - around 2 inches.\nStep 5: Making the Tailor’s Ham - 3\n1. Sew a 1/4” seam, leaving a 2” gap to turn the whole thing right side out. Use a very short straight stitch.\n2. Turn the tailor’s ham right side out.\nStep 6: Making the Tailor’s Ham - 4\nStuff the tailor’s ham until it is very firm. This needs to hold it’s shape even when pressure is applied to it.\nThere are several different types of stuffing you can use. The most important thing in selecting a stuffing is that it is able to tolerate heat.\nHere are some options for stuffing:\n* Sawdust\n* Cotton Batting/stuffing\n* Wool wadding/batting/stuffing\n* Cut up bits of scrap fabric - must be a natural fiber! (Wool, cotton, or silk)\n* Walnut Pet Bedding\n* Sand (gets heavy though)\nYou can actually combine stuffings if need be.", "316" ], [ "Robin's Egg Bird Nest Bed Lounge\nIntroduction: Robin's Egg Bird Nest Bed Lounge\nHave you ever wanted to sleep in a giant bird's nest bed? Now you can! Comfortably fits an adult, if you like to sleep curled up.\nSupplies\nTools needed:\nSewing machine\nSewing pins and safety pins\nScissors\nDisappearing ink fabric marker\nOverlock machine/Serger (optional, zigzag stitching may be used)\nElectric bread cutting knife\nMeasuring tape/ruler\nPaintbrush\nSupplies:\n4 Firm foam crib mattresses, Length 51.25\" Width 27.25\" Depth 5\". I used crib mattresses from a store display.\nOne king or queen sized mattress pad. It's not recommended to use one with down filling, as feathers may be sharp.\nOne brown, king sized sheet.", "673" ], [ "Dye your own sheet brown for a more natural look.\nOne white sheet or poly-cotton material for making the egg pillows.\nOne turquoise sheet or poly-cotton material for making the pillow covers.\nA very large bag or box of poly-fill.\nBrown, turquoise and white threads.\n1-3 cans of Heavy Duty Spray Contact Adhesive for foam.\nElastic, either 3/8\" wide or 1/2\" wide.\nMetal snaps, press-on or sew-on.\nBlack and brown acrylic craft paint.\nStep 1: Step 1: Mark and Cut.\nMark and cut your mattresses, as shown in photo.\n(Diagram shown, as I forgot to take photos of this step.)\nStep 2: Step 2: Cut the Edges of Your Nest\nCut the edges as shown in photo.\n(Diagram shown, as I forgot to take photos of this step.)\nStep 3: Step 3. Rounding Edges.\nUse your electric knife to round your nest edges, as shown in photo.\nStep 4: Step 4: Mattress Pad\nPlace the pad on the nest, as shown in photo.\nStep 5: Step 5: Mark the Inner Edges\nMark the inner edge of your nest, as shown in photo.\nStep 6: Step 6: Sew the Inner Edge\nSew along your marked/pinned circle on the pad, as shown in photo.\nStep 7: Step 7: Finish the Mattress Pad\nFinish the mattress pad, as shown in photo.\nStep 8: Step 8: Start Your Pillow Forms and Pillow Covers.\nCut out and finish the raw edges of your pillows.\nStep 9: Step 9: Make Your White Egg Pillow Forms\nFollow directions in photo.\nStep 10: Step 10: Start Your Pillow Covers\nMake rolled hems on the snap facings and pin onto the front/back of the egg.\nStep 11: Step 11: Sew the Pillow Covers and Add Snaps\nSew sides and add the snap closures to the facing and front/back.\nStep 12: Step 12: Perfect the Pillow Cover Fit\nCorrect the fit of your pillow covers.\nStep 13: Step 13: Make the Brown Cover Sheet\nPlace sheet on nest and pin 4 side darts.\nStep 14: Step 14: Sew the Darts\nSew and trim the darts.\nStep 15: Step 15: Mark the Nest Edge\nPin and mark the bottom edge of the nest.\nStep 16: Step 16: Trim and Glue\nTrim all around the nest and place a glue dot on the dart seam edge.\nStep 17: Step 17: Pin and Sew the Elastic Casing/ Bottom Hem.\nFollow steps in photo.\nStep 18: Step 18: Hang the Brown Cover Sheet Up and Mix Your Paint.\nFollow directions in photo.\nStep 19: Step 19: Paint Sticks and Twigs\nPaint as many or as few twigs as you like. Have fun with it!\nStep 20: Step 20: Insert and Size the Elastic\nFollow steps in photo.\nStep 21: Step 21: Sew Elastic Together and Finish the Seam\nFollow steps in the photo.\nStep 22: Step 22: Hang Out in Your New Nest!\nCongrats, you're done! If you don't have room to place your nest on the floor, it can be used as a topper on a full size or larger bed.\n(Child size clothing mannequin for size reference)", "748" ], [ "Cheap Child's Sith Trooper Costume\nIntroduction: Cheap Child's Sith Trooper Costume\nWith Coronavirus lockdown in full swing, do you need to do something with all those cardboard boxes? Well, I have just the project for you. In this Instructable, I will show you step by step how to build a Sith Trooper costume made entirely out of cardboard, and craft foam! In fact, the materials cost less than 30 dollars! (Not including the shirt and pants)\nStep 1: Gather Your Supplies\nThe supplies needed are as follows:\n- REFERENCE PICTURES (These will help you so much. It almost doesn't matter how much you love whatever character you're building. There are SO MANY details.)\n- Scrap paper to draw the pattern onto.\n- Tape\n- Cardboard (Lots. I'm honestly not sure how much I used)\n- Glue (I used hot glue for most of the costume, but I also used super glue to attach the tinier details)\n- Scissors\n- Caulk\n- Sealer/Primer (I used PlastiDip)\n- Red Spray Paint\n- Black Acrylic Paint\n- Velcro\n- Black Longsleeve Shirt\n- Black Pants\n- Black Gloves (I forgot to purchase these)\nStep 2: Making the Pattern: Part 1a\nThe first step of making the pattern is wrapping the limb or body of the \"client\" (little brother). Most experts on the internet such as <PERSON>, and Odin Makes use aluminum foil, but paper works ok for this project. Just keep in mind that the foil will work better for tighter curves, such as the head or chest. The hardest limb was the thigh. You can see above how I wrapped the lower thigh, then taped more paper on top to cover the upper thigh.\nStep 3: Making the Pattern: Part 1b\nThe one piece of the pattern that I did not use the wrapping technique was the chest. I laid out my brother's shirt and drew the shape of the chest piece on paper. Please note that the pattern did not give enough length for the shoulders. I added an extra piece of cardboard on each side to bridge the gap.\nStep 4: Making the Pattern: Part 2\nNext, you want to draw the shape of the armor onto the paper. This is where reference pictures will come in handy! You may want to also draw large details or ideal locations for seams during this step as well. When considering seams, also think about any sharp corners that are included in the design. For example, the shins square out at the front, but it will be difficult to remember exactly where this detail is when the pattern is flat. (Don't worry about getting the lines perfectly straight. This will be fixed later!)\nStep 5: Making the Pattern: Part 3\nNow you will cut the pattern off the subject, and attempt to lay the pattern down flat.", "286" ], [ "Some pieces, such as the bicep will lay down flat, no problem. Other pieces, such as the calf piece (pictured above) will need to be cut further.\n1. Locate where the pattern is resisting and rising up off the table.\n2. Draw a line from the edge of the pattern, to about the center of the problem area.\n3. Draw registration marks. They are the lines that are perpendicular to the cut line. These will help you line up the pattern later.\n4. Cut the line.\n5. Try to lay the pattern down flat. If the previous steps did not completely solve the problem, go back to step 1.\nStep 6: Making the Pattern: Part 4\nFor the shins, you will need to make extra cuts to create the sharp corners seen on the front of the shin. Take a ruler and redraw the lines that you made while the pattern was still on the limb. You can see where I drew my lines. Once you draw the lines, label the lines so that you remember which ones connect where. I forgot to do this, and it makes later steps harder.\nExample: If you draw a line, you will label each side of the line the same letter A | A B | B etc\n(This step isn't too complicated, and it barely warranted a step. However, these cuts are necessary to make the nice sharp angles seen on the shin.)\nStep 7: Tracing the Pattern\nNow you will trace the pattern onto cardboard. Once you trace one side, label it either left or right, then flip the paper and trace the pattern for the opposite side. You can see in the picture above that I used the left back pattern to create one piece so that there wouldn't be any ugly seams on the back. This is done by tracing the pattern once, then flipping it and tracing the opposite side right next to the initial tracing.\nWhen tracing, be aware of any creases or shipping stickers that may be on the cardboard.", "316" ] ]

[ 6212, 10874, 4158, 7940, 3960, 1895, 6390, 3431, 592, 4866, 3514, 996, 7297, 5812, 7651, 6461, 5371, 2998, 4148, 1358, 2075, 10057, 8762, 637, 6567, 3422, 5905, 10178, 2586, 9821, 3649, 1892, 11259, 9986, 384, 5560, 1283, 3381, 9521, 9008, 3270, 2407, 4648, 6575, 9429, 1388, 10767, 9843, 5279, 5269, 842, 2021, 7087, 5571, 8925, 10300, 10558, 3242, 5496, 5038, 4724, 7279, 2786, 7502, 5948, 3740, 6162, 8492, 1680, 4214 ]

[ [ "Integrating the geodesic equation to obtain Newtonian energy of test particle\nI am studying General Relativity, and have come across a question that I am finding rather intractable:\nIn Newtonian Theory, the energy equation for a test particle in orbit around a point mass is: $$\\frac{v^{2}}{2} + \\frac{\\ell^{2}}{2r^{2}} - \\frac{GM}{r} = \\mathcal{E}$$ Where $r$ is the radius, $v$ is the radial velocity, $\\ell$ is the angular momentum per unit mass, $\\mathcal{E}$ is the constant energy per unit mass and $-GM/r$ is the gravitational potential. For the <PERSON> solution show that the integrated geodesic equation may also be written in the form: $$\\frac{v_{s}^{2}}{2} + \\frac{\\ell_{s}^{2}}{2r^{2}} + \\Phi_{s}(r) = \\mathcal{E}{s}$$ Where $v{s} = \\mathrm{d}r/\\mathrm{d}\\tau$, and $\\ell_{s}$ and $\\mathcal{E}_{s}$ are constants.\nI am not really sure what it means by integrating the geodesic equation. My understading is that the geodesic equation is given by:\n$$\\frac{\\mathrm{d}^{2} x^{\\lambda}}{\\mathrm{d} \\tau^{2}} + \\Gamma^{\\lambda}_{\\mu\\nu}\\frac{\\mathrm{d} x^{\\mu}}{\\mathrm{d} \\tau}\\frac{\\mathrm{d} x^{\\nu}}{\\mathrm{d} \\tau} = 0$$\nWhere $\\Gamma^{\\lambda}_{\\mu\\nu}$ is the affine connection. However, this leads to a system of equations, none of which, when integrated, yield the form given in the question.\nI'm sure that I am missing something fundamental and simple, but I just cannot find it in any of the references or materials that I have been given.\nI thought that perhaps integrating the geodesic equation directly would be the way to go, but I do not end up with the correct solution:\n$$\\int\\left(\\frac{\\mathrm{d}^{2} x^{\\lambda}}{\\mathrm{d} \\tau^{2}} + \\Gamma^{\\lambda}{\\mu\\nu}\\frac{\\mathrm{d} x^{\\mu}}{\\mathrm{d} \\tau}\\frac{\\mathrm{d} x^{\\nu}}{\\mathrm{d} \\tau}\\right)\\:\\mathrm{d}\\tau = \\mathcal{E}{s}$$\nWe note that as integration is distributive over addition, we find:\n$$\\frac{\\mathrm{d}x^{\\lambda}}{\\mathrm{d}\\tau} + \\int\\left(\\Gamma^{\\lambda}{\\mu\\nu}\\frac{\\mathrm{d} x^{\\mu}}{\\mathrm{d} \\tau}\\frac{\\mathrm{d} x^{\\nu}}{\\mathrm{d} \\tau}\\right)\\:\\mathrm{d}\\tau = \\mathcal{E}{s}$$\nWe note that if we let $\\lambda = r$, then this becomes proportional to $v_{s}$ and thus I am missing a factor of $v_{s}$.\nEdit 2: After the very helpful comments below, I went back and did the question again, this time getting stuck at a different point.\nSo we find that in the $\\lambda = t$ case, the only <PERSON> symbols $\\Gamma_{\\mu\\nu}^{t}$ that are non-zero are when $\\mu = t$, $\\nu = r$ or vice versa.", "394" ], [ "How to find the trajectory of stationary action of a photon\nI am trying to work through a \"check your understanding\" question on p.393 of the textbook From Photon to Neuron by <PERSON>. The action functional S of a photon's trajectory is proposed to be\n$S [\\underline X^\\mu(\\xi),e(\\xi)] =\\frac{\\hbar}{2} \\int d\\xi (e^{-1}||\\dot {\\underline X}||^{2} )$\nwhere $\\mu$ = 0,1,2, or 3. $\\underline X^\\mu$ are spacetime coordinates; $\\underline X^0$ is $ct$. The parameter $\\xi$ is some index along the trajectory. The variable $e$ is described as a metric necessary so that different parameterizations of the same path give the same action.", "394" ], [ "The dot denotes differentiation with respect to $\\xi$ and $||\\dot {\\underline X}||^{2} $ is the Lorentz invariant interval $ -(c \\dot t)^2 + (\\dot r)^2 $.\nThe reader is asked to show that the equation above is stationary under any trajectory that satisfies\n$0 = e^{-2} ||\\dot {\\underline X}||^{2}$ and\n$e^{-1} \\dot {\\underline X} =$ constant.\nIt's not clear to me if the second equation is implying an <PERSON> summation.\nHere is what I have tried: I introduced a small variation in both the spacetime coordinates and metric along a path and examined the action of this new worldline:\n$S [\\underline X^\\mu+ \\Delta \\underline X^\\mu,e + \\Delta e] =\\frac{\\hbar}{2} \\int d\\xi \\bigl[(e +\\Delta e )^{-1}||\\dot {\\underline X}+\\Delta\\dot {\\underline X} ||^{2} \\bigr]$\n$\\approx \\frac{\\hbar}{2} \\int d\\xi (1 -\\frac{\\Delta e}{e} )\\bigl( ||\\dot {\\underline X}||^2+2 \\dot {\\underline X}\\Delta\\dot {\\underline X}^{2} + ||\\Delta\\dot {\\underline X}^{2}||\\bigr) $\nI then subtracted the action of the original worldline to get\n$ \\Delta S \\approx \\frac{\\hbar}{2} \\int d\\xi \\bigl(\\frac {2\\dot {\\underline X}\\Delta \\dot X}{e}\n+\\frac {{\\Delta \\dot X}^2}{e}\n$ $ +\\frac {2 \\dot X \\Delta \\dot X \\Delta e}{e^2} $ $ +\\frac {\\Delta \\dot X^2 \\Delta e}{e^2} $ $ + \\frac {|| \\dot X||^2 \\Delta e}{e^2} \\bigr) $\nI figured I could neglect terms that were second order in $\\Delta$. That leaves the first and last term in the equation above. The last term must equal zero; this satifies one of the two conditions I set out to show. But shouldn't the first also have to equal zero, not a constant?\nI am hoping someone can help me track down my error(s), explain if one must vary $e$ in addition to $X$, and clarify if the second condition stated above is an <PERSON> summation, i.e. if $ \\dot {\\underline X} = c \\dot t - \\dot r$. Thanks!", "955" ], [ "Unable to Reconcile my Understanding of Length Contraction with the Lorentz Transformation\nHello Stack Exchange,\nI'm currently taking an undergraduate course in Special Relativity. I thought that I understood the material, but reviewing for the test has made my more confused than when I began. Particularly we were given the following problem:\nA spaceman is chasing an alien space ship. As seen from a stationary observer on Earth, the aliens are going at a constant speed of $0.4c$ and the spaceman is going at a constant speed of $0.6c$. Initially they are at $1\\space lightyear$ apart. In the spaceman's reference frame how long does it take for the aliens to be caught?\nPreface\nThe correct answer is given as 4 years.\nThey arrived at this answer by calculating how long it would take in the Earth frame: $\\frac{1 \\space light year}{0.6c - 0.4c} = 5\\space years.$ Then the professor noted that the astronauts time runs more slowly because it is moving relative to the earth at $0.6c$, so the duration of the chase in the astronaut's frame is $\\frac{1}{\\gamma}5 * 0.85 = 4\\space years$. This solution made sense to me AFTER reading it.\nI was able to solve it in another way. I parameterized the spacemans's worldline in the Earth frame as $$\\vec r_S = (0.6\\lambda, \\lambda)$$ In the earth's frame, the alien's worldline is $$\\vec r_A = (0.4\\lambda + 1, \\lambda).$$ NOTE, these both are written in terms of $(x, ct)$. If we transform into the spaceman's frame, then according to the Lorentz Transform, the new form of the world lines will be $(x', ct') = ( [\\gamma (x - \\frac{u}{c}ct)],\\space[\\gamma (ct -\\frac{u}{c}x]))$.", "275" ], [ "In this primed frame, $$\\vec r'_S = (0, 8\\lambda)$$ $$\\vec r'_A = (1.25 - 0.25\\lambda, 0.95\\lambda - 1.75)$$ To find the time of the collision, I found where $x'_S = x'_A$. Skipping the algebra, this occurs at the coordinates $$\\lambda = 5: (x', ct') = (0, 4)$$ -- just as expected.\nMy question\nI initially got this problem wrong because I tried to find the solution using length contraction in the spaceman's frame. I reasoned that if the spaceman is moving relative to Earth, then his measurement of distances in the x-direction will be contracted and shorter by a factor of $1/\\gamma$. When we discussed the twin paradox in class, we talked about how the Earth-twin will \"see\" Rocket-twin's clock tick more slowly, which explains why Rocket-twin thinks the trip to the star is shorter. Then we talked about how Rocket-twin will see the length of their trip contracted, because \"1 m\" in their frame is shorter than a meterstick in the Earth's frame, and the distance was originally measured in the Earth's frame. See this question for another instance of this logic.\nThis reasoning failed. If the distance between the man and the aliens measured on Earth is contracted in the man's frame by $1/\\gamma \\mid \\beta=0.6$, then he will see the aliens as only $0.8\\space lightyears$ away initially. Additionally, we look at the slope of $r'_A$ in the primed frame, we see that to the spaceman the aliens are moving toward him at $0.263c$. So, shouldn't he see the chase take only $\\frac{0.8}{0.263} = 3.04\\space years$?\nEven ignoring this incorrect solution. If the alien's speed is $0.263c$ toward him, then shouldn't he see them travel $4 * 0.263c = 1.052\\space ly$ in his frame?\n1.) Why can't I use length contraction and relative velocity to solve this problem?\n2.) Why do I calculate the alien's moving 1.052 light years in the spaceman's frame? MORE than in the Earth's frame?", "272" ], [ "Relationship between Coordinate Time and Proper Time\nWhile I was reading <PERSON> book on relativity, I was unable to derive the correct relationship between coordinate time $dt$ (the book defined it as the time measured by a clock located at $r=\\infty$ from the source of gravity) and proper time $d\\tau$ from the definition of metric.\nThe book states that for a weak and static gravitational field, $g_{00}(r)=-\\left(1+\\frac{2\\Phi(r)}{c^2}\\right)$ (with the metric signature $(-1,1,1,1)$ and $\\Phi(r)$ is the gravitational potential) and the proper time $d\\tau=\\sqrt{-g_{00}}\\,dt$.\nFrom the gravitational redshift result I know that the above result is correct (in a more unambiguous form $d\\tau=\\sqrt{-g_{00}(r_\\tau)}\\,dt$).\nHowever, if I simply use the formula for spacetime interval $ds^2=g_{\\mu\\nu}dx^\\mu dx^\\nu$ (assuming two clocks that measure proper time and coordinate time are at rest relative to each other), I have\n$$ ds^2=g_{00}(r_\\tau)c^2d\\tau^2=g_{00}(r_t)c^2dt^2=-c^2dt^2\\ \\implies \\sqrt{-g_{00}(r_\\tau)}\\,d\\tau=dt$$ This suggests that time flows faster with a lower gravitational potential which is incorrect.\nI'm not sure why the above method lead to a wrong conclusion, did I misunderstood the the definition of proper time, coordinate time or spacetime interval?\nUpdate:\n1. One mistake I've made is letting $ds^2=g_{00}(r_\\tau)c^2d\\tau^2$, which should be $ds^2=-c^2d\\tau^2$ by definition. However, I'm confused about two definitions of $ds^2$ now.", "394" ], [ "$ds^2=-c^2d\\tau^2=g_{\\mu\\nu}dx^\\mu dx^\\nu$, this suggests that $g_{00}$ is always $-1$ for the frame that measures proper time, but in my problem $g_{00}$ is a function of $r$ which is only equals to $-1$ if $r=\\infty$, how could two both be true at the same time?\n2. Assuming $ds^2=-c^2d\\tau^2$ is true, as all the answers pointed out that $d\\tau=\\sqrt{-g_{00}}\\,dt$. But by the definition of $g_{00}$ and $ds^2$ the $g_{00}$ used here must be $-(1+2\\Phi(r_t)/c^2)=-1$, but I want $g_{00}$ here to be $-(1+2\\Phi(r_\\tau)/c^2)$ so that $$d\\tau=\\sqrt{-g_{00}}\\,dt=\\sqrt{1+2\\Phi(r_\\tau)/c^2}\\,dt\\approx (1+\\Phi(r_\\tau)/c^2)\\,dt\\ \\implies \\frac{d\\tau-dt}{dt}=\\frac{\\Phi(r_\\tau)}{c^2}=\\frac{\\Phi(r_\\tau)-\\Phi(r_t)}{c^2}$$\nPlease correct me if I've made any mistakes!", "394" ], [ "The above answers seem to nicely summarize why charge is conserved in every frame of reference. I would like to take a different approach as to why that makes sense, and why the charge conservation law holds.\n1. Charge, current and conservation:\nThe most simplest way to state the conservation of charge is to say, $$\\frac{dQ}{dt} = 0$$\nThat the rate of change of charge in time is $0$, implying that the quantity of charge is a constant.\nBut, sometimes charge can decrease in a system. This does not violate the supreme principle, but rather states that charge can 'leak' or flow through an area, causing the charge in the system to decrease, and the charge outside to increase. So, the amount of charge in the entire universe is the same, but for smaller systems the above equation may not hold true.\nConsider a box with some charge inside of it. The charge can flow out through any of the faces of the box, thus decreasing the overall charge inside (it can also increase if the charges are instead entering the box). So, you need to take into account this flow of charges, called a current to make sure that the conservation law holds. The resulting mathematical form is:\n$$\\frac{d\\rho}{dt} + \\nabla . J^i = 0$$\nwhere the $\\rho$ represents the density of charge inside the box, and $J^i$ is the current vector, because current can flow through the $x$, $y$, and $z$ axes; so we use a vector to keep track of them all. What the above expression says is: the rate of change of charge in the box and the rate of change of current flowing in or out of it, is going to be conserved.\n2. Four vectors, dot products and Lorentz invariance:\nIn Relativity, we use something known as four-vectors, which are 4 dimensional vectors. Usual vectors have only three components: one corresponding to each dimension of space; in Relativity, we consider a fourth dimension: time.", "780" ], [ "So, vectors in Relativity have four components, one corresponding to time, and three to space. We denote these vectors by $$A^{\\mu}, \\mu = (0, 1, 2, 3)$$ where the $0$ index corresponds to the time component and the other three to the space components.\nNow, let's move on to Lorentz invariance. In Special relativity, whenever we want to consider events from a different reference frame, we use something known as Lorentz transformations. I am going to leave a few nice resources in the further reading below, but for now, that is enough information.\nIf a certain quantity does not change when the Lorentz transformation is applies to it, we say it is Lorentz invariant.\nSo, some of the things that are always Lorentz invariant are the dot product between two four-vectors. Again, for length purposes, I will leave a link to some resources below, but simply put, dot products between two vectors can be denoted as: $$Product_{dot} = A^\\mu B_\\mu$$\nThe only constraint is that the index of the four vectors should be the same and they should be repeated upstairs and downstairs. Expanding this expression, we get: $$A^{\\mu}B_{\\mu} = -(A^0 B_0) + (A^1 B_1) + (A^2 B_2) + (A^3 B_3)$$ which is a scalar and is Lorentz invariant. These scalars are called Lorentz scalars.\n3. Bringing it all together:\nIn Special Relativity, we denote the charge and current of a particle as a four vector $J^{\\mu}$. The time component is $\\rho$ and the space components are $J^i$. There is another four vector $\\partial_{\\mu}$ which is defined to be: $$\\partial_{\\mu} = \\left (\\frac{\\partial}{\\partial t}, \\frac{\\partial}{\\partial x}, \\frac{\\partial}{\\partial y}, \\frac{\\partial}{\\partial z}\\right)$$\nOkay. Now, particles have some properties, like mass and charge that do not change when you shift frames. Similarly for the conservation of charge, you can write it as $$\\partial_{\\mu}J^{\\mu} = 0$$ which is a dot product, so it is naturally a <PERSON> invariant.\n4. So, can charge vary for observers?\nI took an unconventional way of answering here, by first showing the true way of expressing the conservation of charge and then going through a long way to show why the law hold even when our frames change.", "418" ], [ "Equations of motion for a certain constrained system\nAs an exercise in Lagrangian and Hamiltonian mechanics, I am looking at a system with the following Lagrangian:\n$$L=\\dot R \\cdot\\dot R-\\theta\\dot R\\cdot (SR)+\\lambda(R\\cdot R-1) $$\n$R$ is a vector in 4D Euclidean space, constrained to lie on the unit hypersphere ($\\lambda$ is the Lagrange multiplier for this constraint). $S$ is a skew-symmetric matrix that squares to $-1$. The Euler-Lagrange equations result in the following equations of motion:\n$$\\ddot R-\\theta S\\dot R-\\lambda R=0$$ $$R\\cdot R=1$$\nMy first difficulty is that I cannot figure out how to solve for $\\lambda$ to determine the constraint forces. My second difficulty is in finding the general solution; I can find specific solutions of the form: $$R=e^{At} R_0$$ Where $A$ is assumed to be skew-symmetric so that the constraint is guaranteed to be satisfied. This has a unique solution $A=\\theta S/2$ when $\\lambda=\\theta^2/4$ (which is problematic; there does not appear to be enough degrees of freedom to allow for arbitrary initial positions and velocities) and and infinite family of solutions for $\\lambda < \\theta^2/4$ (which I'm not sure how to combine to get a general solution).\nNever mind those problems. Now I try to form the Hamiltonian. The conjugate momenta are:\n$$ P=\\frac{\\partial L}{\\partial \\dot R}=2\\dot R-\\theta SR$$\nWhich is invertible to find the velocity, and:\n$$ \\pi=\\frac{\\partial L}{\\partial \\dot \\lambda}=0 $$\nWhich obviously is not.", "101" ], [ "Not sure what to do about the constraint, I just evaluate it in computing the Hamiltonian and the equations of motion, so that term disappears. I get a Hamiltonian:\n$$H=\\dot R \\cdot\\dot R=\\frac{1}{4}P\\cdot P+\\frac{1}{2}\\theta P\\cdot (SR)$$\nPlugging this into the Hamiltonian equations, I get the result:\n$$\\dot P=\\frac{1}{2}\\theta SP$$ $$\\dot R=\\frac{1}{2}P+\\frac{1}{2}\\theta SR$$\nAnd so:\n$$\\ddot R=\\theta S\\dot R+\\frac{1}{4}\\theta^2 R$$\nWhich is the same equations of motion that I got before, except that $\\lambda=\\theta^2/4$ specifically.\nSo that seemed to work. Except: I wanted to verify that these equations of motion preserve the constraint. Evaluating the Poisson bracket of the constraint with the Hamiltonian shows that it is proportional to $P\\cdot R$, so that has to be zero in the initial conditions. But the Poisson bracket of $P\\cdot R$ gives the expression:\n$$\\frac{1}{4}(P\\cdot P+\\theta P\\cdot(SR)+\\theta^2)$$\nWhich should be zero to ensure that the constraint is preserved - but it isn't zero for the unique solution that I found above for $\\lambda=\\theta^2/4$, even though that solution does preserve the constraint by construction!\nSo I'm trying to figure out (1) how to solve for the constant $\\lambda$ and how to get a general solution to the equations of motion if possible, and (2) how to appropriately deal with the constraint in the Hamiltonian formalism, or (3) if I've just made a mistake somewhere. Hoping there is someone out there who can point me in the right direction. Thanks very much.", "101" ], [ "Runge Kutta Approach to Relativistic <PERSON> Problem\nI am attempting to solve the relativistic <PERSON> problem using fourth order Runge - Kutta, however I am having trouble and am unsure why I simply cannot get the correct orbits no matter how I adjust the initial values. My orbits are not even incorrect but they are nonsensical, I was wondering if there are issues with the Runge - Kutta algorithm when solving such probelms? The geodesic equations in Schwarzschild spacetime (in geometric units) are:\n\\begin{align} &\\frac{d^2r}{d\\tau^2} = \\frac{M}{r(r - 2M)} \\left(\\frac{dr}{d\\tau}\\right)^2-\\frac{M(r - 2M)}{r^3} \\left(\\frac{dt}{d\\tau}\\right)^2 + (r - 2M) \\left(\\frac{d\\phi}{d\\tau}\\right)^2 \\[0.5em] &\\frac{d^2t}{d\\tau^2} = - \\frac{2M}{r(r - 2M)} \\frac{dr}{d\\tau} \\frac{dt}{d\\tau} \\[0.5em] &\\frac{d^2\\phi}{d\\tau^2} = - \\frac{2}{r} \\frac{dr}{d\\tau} \\frac{d\\phi}{d\\tau} \\end{align}\nWe can convert the above to a system of 6 1st order ODE's by setting: \\begin{align} y_1 = r \\[0.5em] y_2 = \\frac{dr}{d\\tau} \\[0.5em] y_3 = \\phi \\[0.5em] y_4 = \\frac{d\\phi}{d\\tau} \\[0.5em] y_5 = t \\[0.5em] y_6 = \\frac{dt}{d\\tau} \\end{align}\nSo then, we obtain 6 1st order ODEs which can be solved using the fourth order Runge - Kutta. For example, I tested my code on mercury with the following parameters (geometrized units): \\begin{align} &\\text{Mass of sun: } 1474 m \\[0.5em] &\\text{Mecury radius at perihelion: } 46.002\\times 10^9 m \\end{align}\nI am not sure about the initial values for the Runge Kutta so I tried a range such as $$ [y_1(0), y_2(0), y_3(0), y_4(0), y_5(0), y_6(0)] = [46.002\\times 10^9, 0, 0, 1\\times 10^{-16}, 0, 1] $$ Despite the range of initial values i have tried, I cannot seem to get even a decent orbit.\nIs there a problem with using Runge - Kutta to solve these equations or should there be a more deterministic way to obtain the initial values?", "394" ], [ "Warp drive causality issue, and a possible error in a paper?\nTake a look at this paper on \"Warp Drives and Causality:\" https://journals.aps.org/prd/abstract/10.1103/PhysRevD.53.7365\nThe author attempts to argue that the Alcubierre Drive spacetime could exhibit Closed Timelike Curves, if one is to consider a \"Lorentz Transformation of the coordinates.\" In such coordinates, one finds that a light ray emitted on board the ship could travel backwards in time in such coordinates.\nThe author seems to confuse unphysical coordinate artifact with actual phenomenology. As far as I understand, in GR, one has the freedom to label points on the spacetime manifold by whatever $t, x, y, z$ they like, but the metric tensor remains a physical invariant, regardless of what you call your coordinates. However, its representation in a coordinate system will of course depend on your choice of coordinates.\nTo be mathematically precise, one cannot perform a Lorentz Transformation on the coordinates within the context of a curved spacetime as in GR.", "275" ], [ "If we want to of course, we could transform <PERSON> coordinates, to coordinates which look like a Lorentz Boost, but then we must transform the representation of the metric as well, and in our case we don't have the Minkwoskian structure as we do in SR.\nA light beam propagating inside the vessel will remain within its local light cone, regardless of what you call your coordinates, as specified in <PERSON>'s original paper. The \"Lorentz transformation\" attempted by the author does not hold.\nGenerally speaking, to find a CTC, we are looking for a Timelike trajectory for a particle in the spacetime that returns to the same point on the spacetime manifold. In summary, I do not see that a CTC arises, but that the paper concludes the existence of CTC from a violation of causality in special relativity which is exactly what a CTC does not entail AND an attempt to apply special relativity beyond its domain of applicability. Lorentz Boosts could only be defined Locally at a point in GR, and not the entire spacetime.\nI am only a student, and the author is surely more experienced in GR than me, but I can't see where I am wrong: could someone kindly explain to me where my attempted refutation fails? Sorry for the excessive text...", "275" ] ]

[ 6029, 7306, 2180, 6600, 8351, 1282, 10483, 11211, 760, 9196, 11382, 1842, 2578, 315, 10517, 5178, 7996, 7815, 7229, 2510, 4776, 5731, 3726, 3438, 3712, 191, 8948, 6306, 8376, 11069, 10815, 10274, 1592, 9764, 1538, 10386, 171, 10870, 9453, 956, 10186, 7728, 3652, 1159, 494, 11356, 11189, 2386, 6533, 5819, 6937, 10440, 9569, 4479, 8546, 6231, 500, 2519, 8909, 4529, 4049, 10847, 460, 1448, 2718, 4950, 7635, 2043, 1418, 8108 ]

[ [ "The question can be interpreted in a few different ways: both what you mean by having the $xy$ slices of the 3-space Euclidean, and what you mean by it being non-Euclidean in the $z$ direction.\nThe suggestion of taking a Euclidean plan and cross it with a non-Euclidean curve only works if you look at the global structure. Any (smooth) curve is locally Euclidean, i.e. you can straigten it out, so locally the 3-space will be Euclidean. However, if you take $\\mathbb{R}^2\\times S_1$, i.e. Euclidean plane times a circle, it will not be the same as Euclidean $\\mathbb{R}^3$.\nHowever, I suppose what you had in mind was local geometry, not global geometry. Normally, by saying locally Euclidean, we just mean that in an infinitessimal neighbourhood of any point, the space is Euclidean. I'm not completely sure if this necessarily will always allow you extend this to a bigger region (of positive size, although perhaps small).\nAnother question is if the $xy$ slice itself is Euclidean, i.e. has an Euclidean metric, or if the embedding into the 3-space should also be non-curved.\nLet me give you a few examples and discuss them. The way I describe the metric, i.e. distance function, on 3-space parametrised by $(x,y,z)$ is on the form $$ds^2=dx^2+dy^2+dz^2 \\iff s'=\\sqrt{(x')^2+(y')^2+(z')^2}$$ where $ds$ is the infinitesimal distance between $(x,y,z)$ and $(x+dx,y+dy,z+dz)$, and the length of a path $(x(t),y(t),z(t))$ is computed by integrating $s'$.", "586" ], [ "This is the Euclidean metric on 3-space.\nAn alternative metric I can make is $$ds^2=f(z)^2\\cdot(dx^2+dy^2)+dz^2$$ which means the $xy$ plane is scaled by a factor $f(z)$. Note that if we enter new coordinates $u=f(z)\\cdot x$, $v=f(z)\\cdot y$ and restrict attention to the surface with constant $z$ (i.e. all $dz$ terms disappear), we find the metric on the surface $S_z$ to be $ds^2=f(z)^2\\cdot(dx^2+dy^2)=du^2+dv^2$, so this is still a Euclidean plane. However, in the function $f(z)$ is non-constant, the 3-space is curved. What's more (and perhaps less intuitive) is that the $S_z$ planes lie curved inside the 3-space. One way to see this is that the shortest path between two points in $S_z$ will tend to leave $S_z$ and take a short-cut through the side of $S_z$ in 3-space for which $f(z)$ is lower: on this side, distances are shorter, just as the shortest path between to points on a circle in the plane will pass through the interior of the circle rather move along the circle.\nAnother metric we can make is $$ds^2=dx^2+dy^2+h(x,y,z)^2\\cdot dz^2$$ for some arbitrary positive function $h(x,y,z)$. Again the constant $z$ slices, $S_z$, are Euclidean planes: this time with no scaling involved. Instead, distances along the $z$ direction are scaled. This time, the embedding of the $S_z$ planes itself is non-curved: not only is the metric on $S_z$ equal to $ds^2=dx^2+dy^2$, but there are no short-cuts by passing out of $S_z$.\nMathematically, the curvature is described locally by the Riemann curvature tensor. This is based on the idea of parallell transportation of vectors: i.e. if I start at a point $P$, pick a direction $u$ (described by a tangent vector) and another vector $w$, I can parallell transport $w$ in the $u$ direction: say to a point $P+\\epsilon u$.", "586" ], [ "An isometry is a way of moving the manifold rigidly within itself, and is inherently an active transformation (a diffeomorphism).\nFrom <PERSON>'s Lecture Notes on General Relativity:\ndiffeomorphisms are just active coordinate transformations... We say that a diffeomorphism $\\phi$ is a symmetry of some tensor $T$ if the tensor is invariant after being pulled back under $\\phi$... The most important symmetries are those of the metric... A diffeomorphism of this type is called an isometry.\nIn the formula $$g^\\prime_{ij}(x')=g_{ij}(x'),$$ it is important to note that the argument $x'$ is the same on both sides -- i.e., the original and transformed metrics are evaluated at the same coordinate values and hence at different physical locations. Of course, there is technically always the trivial isometry $x'(x) = x$.", "578" ], [ "But in general, each point $P$ is mapped by the isometry to a different point $Q$.\n(A passive version with $g^\\prime_{ij}(x')=g_{ij}(x)$ -- note no prime on right-hand side -- would be different and less interesting. This says that the metric looks the same in the old and new coordinates at the same point $P$. Such nontrivial coordinate transformations exist for any manifold -- e.g., adding a constant to each coordinate. Nontrivial isometries, on the other hand, exist only for special manifolds.)\nWe can describe an isometry without even using coordinates. Given any points, curves, and other shapes of interest in a manifold, all their metrical properties and relations (such as lengths and angles) are unchanged when they are transformed into new points, curves, and other shapes by the isometry.\nWe can see that an isometry is very special, since a general manifold with metric will have lots of irregular (but smooth) \"bumps and wrinkles\" as measured by curvature, such that any point can be uniquely identified by the pattern of bumps and wrinkles around it. There will be no way to transform the manifold nontrivially while keeping these patterns the same -- i.e., no possible rigid motion of the manifold within itself.\nA continuous family of isometries is particularly interesting, and leads to the notion of a Killing field.", "578" ], [ "I tis very important to notice that you can do this at a given point, but not at any given curve. In fact, it is true that for geodesics you can define a locally flat coordinate system such that the <PERSON> symbols vanish along the curve. This is compatible with the idea of the equivalence principle for $inertial$ observers.\nHowever, for more general trajectories, it is not possible to define a such a coordinate system: the <PERSON> symbols get corrections due to the acceleration of the trajectory, and these are compatible with the notion of fictious forces that are seen due to non-inertiality.\nThe way to analyze the problem above is by means of the Fermi normal coordinates (FNC).", "578" ], [ "These are a coordinate system that is associated with a timelike trajectory and describes \"what an observer undergoing this trajectory sees\". In case you want learn more about this, I recommend https://arxiv.org/abs/1102.0529. In any case, it is possible to show that the metric in FNC can be written locally around the curve (up to first order in acceleration and curvature) as\n$$\\begin{aligned} &g_{\\tau \\tau}=-\\left(1+2 a_{\\mathrm{i}}(\\tau) x^{i}+R_{0 \\mathrm{i} 0 \\mathrm{j}}(\\tau) x^{i} x^{j}\\right), \\ &g_{\\tau i}=-\\frac{2}{3} R_{0 \\mathrm{jik}}(\\tau) x^{j} x^{k} \\ &g_{i j}=\\delta_{\\mathrm{ij}}-\\frac{1}{3} R_{\\mathrm{ikjl}}(\\tau) x^{k} x^{l} \\end{aligned},$$ where $\\tau$ is the proper time of the trajectory (and the timelike coordinate of the FNC) and $x^i$ denote the proper distance from the trajectory, which are the spacelike trajectories of the FNC. $a(\\tau)$ is the trajectories proper acceleration and $R(\\tau)$ is the curvature tensor along its motion.\nThe <PERSON> symbols to first order in acceleration and curvature then read\n$$\\begin{aligned} \\Gamma_{i j}^{\\tau} &=\\frac{1}{3}\\left(R_{0 \\mathrm{ijm}}+R_{0 \\mathrm{jim}}\\right) x^{m} \\ \\Gamma_{\\tau i}^{\\tau} &=a_{\\mathrm{i}}+R_{0 \\mathrm{i} 0 \\mathrm{~m}} x^{m} \\ \\Gamma_{\\tau \\tau}^{\\tau} &=0 \\ \\Gamma_{j k}^{i} &=\\frac{1}{3}\\left(R_{\\mathrm{j} \\mathrm{km}}^{\\mathrm{i}}+R_{\\mathrm{k} \\mathrm{jm}}^{\\mathrm{i}}\\right) x^{m} \\ \\Gamma_{\\tau j}^{i} &=R_{0 \\mathrm{mj}}{\\mathrm{j}} x^{m} \\ \\Gamma_{\\tau \\tau}^{i} &=a^{\\mathrm{i}}+R_{0}^{\\mathrm{i}}{ }_{0 \\mathrm{~m}} x^{m} \\end{aligned},$$ which can be seen to vanish if $a^i = 0$ (inertial motion) and $x^i = 0$ (on top of the curve).", "804" ], [ "Euclidean derivation of the black hole temperature; conical singularities\nI am studying the derivation of the black hole temperature by means of the Euclidean approach, i.e. by <PERSON> rotating, compactifying the Euclidean time and identifying the period with the inverse temperature.\nConsider the Schwarzschild case as an example. The Euclidean Schwarzschild metric is of course\n$ds^2=\\left(1-\\frac{2M}{r}\\right)d\\tau^2+\\left(1-\\frac{2M}{r}\\right)^{-1}dr^2$\nwhere $\\tau=it$ the Euclidean time. Here $\\tau\\in[0,\\beta]$ with $\\beta=T^{-1}$ the inverse temperature, where the points $\\tau=0$ and $\\tau=\\beta$ are equivalent.", "394" ], [ "(I ignore the 2-sphere part of the metric.)\nOutside but close to the event horizon $r=2M$, we can (after simple some steps) write this as $ds^2=\\frac{\\sigma^2}{16M^2}d\\tau^2+d\\sigma^2$.\nHere $\\sigma^2 \\equiv 8M(r-2M) $, though this is not really relevant for my question.\nNow the next step in all the literature is to require that $\\tau/4M$ is periodic with period $2\\pi$ to prevent conical singularities. I have trouble understanding this.\n* A conical singularity basically means that the point at $\\sigma=0$ looks like the tip of a cone, right? So we have a singularity at $\\sigma=0$. But don't we still have a singularity there for polar coordinates $(r,\\theta)$, since the coordinate chart $\\theta$ is not continuous there?\n* If so, removing the point $\\sigma=0$ would erase the conical singularity, right? Then why do we want to get rid of the conical singularity, why is it any worse than the polar coordinate singularity? Of course polar coordinates just describe flat space without the origin, is this not the case for the conical coordinates?\nClearly I have not understood the concept of a conical singularity...\nLast question: suppose I did understand it, and continued the derivation to get the temperature $T=1/8\\pi M$. Apparently this is the temperature as measured by an observer at infinity, how can I see this? I know the temperature gets redshifted, like frequency, but I don't see where the derivation identifies $T$ with the one measured at infinity.", "272" ], [ "In the image included in your question, one should not view the arrows as literally extending through space or having a spatial length associated to them. The length of these arrows is the magnitude of the field, and they should each be thought of as living inside of their own vector space which is \"internal\" or \"attached\" to a given point in space. Your last statement is essentially correct, there is no \"lateral extension\".\nAs a very simple analogy, imagine a particle moving through space along some trajectory with coordinates $\\gamma(t) = {x(t),y(t),z(t)}$. The trajectory traces out of a one-dimensional curve through space. At every point on this curve, we can talk about the velocity vector, $\\mathbf{v}(t) = \\dot{x}(t)\\hat{\\mathbf{x}}+\\dot{y}(t)\\hat{\\mathbf{y}}+\\dot{z}(t)\\hat{\\mathbf{z}}$. We often draw a picture of the curve and its associated velocity vector as if the velocity vector had a length in space, for example like this:\nDoes the velocity vector literally represent something with a spatial extent? Of course not. We should understand the velocity vector as living in the tangent space $T_{\\gamma(t)}E$ at the point $\\gamma(t)$, where $E$ is the spatial manifold, usually taken to be Euclidean space. There is a separate tangent vector space for every point in space, and these are the spaces where each of the velocity vectors live for each point of the trajectory.", "499" ], [ "Note that the direction that the arrows point has a meaning with respect to space, but their length only tells you the magnitude of the velocity (i.e. the speed). We don't think of the velocity vectors as representing spatial displacement vectors (they can't since a velocity vector has magnitude measured in units of length/time while a displacement vector has a magnitude measured in units of length).\nIn fact, the electromagnetic field should properly be understood as living in the space of 2-forms at each point of space, $\\bigwedge^2 T_pM$ for each point $p$ in $M$, where $M$ is 4-dimensional <PERSON> space.\nThe basic idea is that the \"fields\" we talk about in physics (including quantum fields) take a value at every point in space(time), and the value they take lives in an \"internal space\" at each point. This notion is formalized in the idea of a fiber bundle, where the fibers are the \"internal spaces\" connected to each point of space.\nAddendum\nRemember that the field takes independent values at every point in space. I made a little animation of a plane wave to show this. Note that in the image below each little arrow represents the local field strength and direction, but these arrows each live in the internal space. I can only show a finite number of arrows, but there are more arrows filling all of space in the gaps. Try focusing on just a single arrow.", "499" ], [ "Your first method is the correct one, as long as the starting time is measured from the simultaneous moment at $t=0$ in the Earth's frame. As you probably know, it's not very natural to talk about simultaneous moments for spatially separated events, and this is where part of the subtlety in this question lies.\nBy the way, your first method can be found more simply by just dividing the Earth frame time $6000s$ by the time dilation factor gamma. $$\\frac{3}{5}6000s=3600s\\qquad \\frac{4}{5}6000s=4800s$$\nNow let's go to one of the ships' frames, say the one moving at .8c. The time $t'=0$ is when that ship starts its 90 minute timer, but the other ship started its timer at some earlier $t'$!\nThe event at which the other ship starts its clock is at $$t'=\\gamma(t-vx)=\\frac{5}{3}(0-.8\\times 8400 s)=-11200 s$$ $$x'=\\frac{5}{3}(8400s-.8\\times 0)=14000s$$ So at $t'=0$ the other ship is at $14000s-.946\\times11200s\\approx3405s$, which does not agree with your Lorentz contracted value.", "562" ], [ "Continuing on from this distance, you will find it is $3600s$ until collision again, as in your first method.\nWhy length contraction failed\nIn order to use the length contraction idea, you need to be transforming a 'proper length.' What that means is that the endpoints of the length are both at rest in the original frame. In your case the endpoints of the distance were the two ships, which were not only not at rest, they were at different velocities.\nBut just to show where length contraction would come in, let's consider the proper length with endpoints given by the worldlines $x=0, \\,x=8400s$. We found the transformed coordinates of the point $x=8400s$ at $t=0$ above. Now in the transformed frame the $x=0$ worldline is moving with velocity $-.8c$, so at $t'=-11200s$ it is at $x'=8960s$, and $14000s-8960s=5040s$ which was the contracted length you found in the second method. You can see it has nothing to do with the distance between the two ships.", "586" ], [ "Is the fact that something is coupled to something else mathematically well-defined?\nSort of, because when you say that X and Y are coupled to each other, it means that X and Y interact with each other. This interaction is encoded in a mathematical way, and can appear in many places in different ways (in the action/Lagrangian, in the equations of motion, in the physical scattering amplitude, in the gravitational potential, etc.). I say 'sort of' because the exact mathematical expression which encapsulates the occurrence of the coupling depends on the quantity you're interested in studying. The fact that X and Y interact with each other is a physical statement, which has physical implications - a universe without interactions among any entities is boring because nothing is created, destroyed or modified. Fortunately, our universe is not like that, and hence we exist. X and Y here can be anything, but usually, they correspond to 2 different fields.", "800" ], [ "One counterexample is when people say that the <PERSON> scalar $R$ (not a field) is coupled to a scalar field $\\phi$ in a scalar-tensor theory of gravity.\nDo people use the term differently or does it always mean the same?\nThey typically mean that two entities X and Y, whatever they might be, interact with each other. What X and Y are, and what the mathematical expression for their interaction is, is usually clear from the context.\nUsually, in a QFT, you need to perform perturbation theory to compute physical observables (scattering amplitudes). Amplitudes depend on the coupling $g$. Perturbation theory just means that you approximate the exact answer by writing only the first few terms of it by performing a series expansion in integer powers of $g$. Sometimes you need non-pertubative effects, and even there you will get a functional relationship of the quantity you're interested in in terms of g, e.g. the <PERSON> electron-positron pair production rate depends (schematically) on $e^{-1/g}$ where g = electric charge (coupling).\nIn gravity (GR), the coupling is $\\sqrt{G}$, which is quite small (in SI units, for instance), which is another way of saying that one can approximate GR as a weakly-coupled QFT of gravitons (as long as the energy scales probed are smaller than the <PERSON> scale). This small coupling then gives the physical result that 2 electrons will repel each other due to electrostatic forces much more than they will attract each other due to gravity.\nIn short, a coupling is just a parameter, which tells you how much/how quickly/how slowly something is created/destroyed/modified/exchanges energy and momentum with its surroundings.", "800" ], [ "Dynamically, more natural notion is phase space, which is the space where the evolution is first order in time. Intuitively, it's all the information you need to make the system evolve. Configuration space then arises when phase space has additional structure. Typically, when it is the cotangent bundle of a manifold, configuration space is naturally identified as the manifold in question. In a lot of cases, it makes sense to view configuration space as having half the dimensions of phase space. Intuitively, this works if you can define a Lagrangian/Hamiltonian, or more abstractly a symplectic structure (the fact that your phase space has even dimensions is already a good indicator). You cannot define configuration space without considering the dynamics as well.\nFor electromagnetism in vacuum, there are two degrees of freedom ($2$ polarisation states). And there are many ways to see this.\nYou can get this directly from <PERSON>'s equations.", "40" ], [ "You start with $6$ components of the EM fields. You get rid of $2$ due to the \"static\" <PERSON> equations: $$\\nabla \\cdot E = 0\\ \\nabla \\cdot B = 0$$ so you have $4$ components. Since the equations are of first order in time derivative, this means that $4$ actually corresponds to the dimension of phase space, so halving it, you obtain the $2$ dof's.\nFrom the potentials, you can get the same results. The idea is that <PERSON>'s equations can be derived from the Lagrangian density: $$ \\mathcal L = \\frac{1}{2}(E^2-B^2) \\ = \\frac{1}{2}\\left((\\nabla V+\\partial_t A)^2-(\\nabla\\times A)^2\\right) \\ $$ This time, it looks as if there are $4$ dof's. However, the time derivative of $V$ does not appear, so it is not a dynamical variable, but rather enforces a static constraint (a Lagrange multiplier). So you only have three dof's. Finally, adding gauge invariance, you loose and additional dof, so you obtain $2$ as well. Note that you can similarly get the same result by specifying the gauge (<PERSON>, <PERSON>...).\nIf you are familiar with general relativity, you can similarly prove that the <PERSON>'s equations actually leave $2$ dof's even if you seem to have $10$ dof's for the metric tensor (with the added subtlety that there are more constraint equations and more gauge transformations).\nHope this helps.", "418" ] ]

[ 11272, 1592, 10815, 571, 6804, 7813, 4818, 10240, 6533, 1930, 3176, 3387, 2519, 9370, 1448, 9555, 8297, 6512, 4484, 10821, 5330, 5976, 10169, 9608, 10517, 7947, 8948, 4288, 191, 2561, 141, 3858, 5434, 10452, 2386, 6496, 9862, 9259, 6995, 5740, 8553, 10290, 2578, 6848, 6510, 2133, 2395, 1267, 10133, 2595, 10483, 2645, 8777, 2160, 2785, 10547, 10461, 3830, 7635, 10020, 8938, 9794, 9092, 494, 5604, 10997, 11111, 1426, 6866, 3755 ]

[ [ "Security concerns and legal ambiguities threaten the future of Ukraine’s ‘State in a Smartphone’ · Global Voices\nThe “state in a smartphone” project is one of the most ambitious developments of the current Ukrainian government. Photo by JESHOOTS-com on Pixabay.\nOne year ago, the Ukrainian government released the revolutionary mobile application Diia (Ukrainian for “action”), a cornerstone of President <PERSON>’s campaign promise of making public services convenient and easily accessible via the internet.\nThe Diia mobile app — and its accompanying online e-services portal — allows citizens to digitize their national ID and biometric passport, personal tax number, student ID, and more, and the digital documents wield the same legal power as the original paper ones. Within a year, Ukraine became the fourth European country to have a digital driver’s license and the first country in the world to have a digital passport.\nHowever, a massive data leak last year has raised concerns about the level of protection around users’ personal information. In May 2020, activists discovered about 900 GB of citizens’ personal data being traded by an anonymous chatbot on the popular messaging platform Telegram. The dataset included passport numbers, personal tax numbers, residence information, driver’s licenses, social media passwords, and even bank details of millions of Ukrainians.\nSome public officials accused Diia of leaking data from government registries, while security experts recalled that the Ministry of Digital Transformation had yet to release any security documentation for the app. While journalists and researchers were able to confirm that part of the datasets had come from Ukrainian government registries, no evidence implicating Diia directly has been found.\nOn the anniversary of its launch, Diia app boasts over 6 million users.", "534" ], [ "At the same time, IT specialists and digital rights defenders continue to call on the government to consider all of the risks that e-government and digital identification technology carry, as these may potentially undermine the public's trust.\nDigitizing the nation\nWhile the idea of digitizing public services is not new to Ukraine, Zelensky's is the first administration that has made e-governance a top priority or established a separate ministry entirely dedicated to it — the Ministry of Digital Transformation, headed by <PERSON>.\nOriginally presented in the spring of 2019, the ambitious “State in a Smartphone” program envisioned moving all public services online and providing the majority of the citizens with a means of digital identification. It was later expanded to include goals such as increasing people's digital literacy, expanding internet infrastructure, and creating favorable conditions for the development of the information technology (IT) industry.\nIf implemented successfully, the program could help combat corruption by minimizing the interference and arbitrary decisions of public officials, while significantly reducing state bureaucracy.\nIn addition, Minister <PERSON> has proudly noted that not a single hryvnya from the state budget had been spent on the development of the Diia app — its development team comprised 35 volunteers from the well-known software engineering company EPAM Systems. They later transferred the completed product and relevant technical know-how to the state.\nHow secure are citizens’ data in Ukraine?\nInitially, the ministry announced that Diia used BankID technology from several leading Ukrainian banks for user authorization, and that it utilized a secure cloud server for the transfer of encrypted data.\nStill, few disclosures were made about the security of citizens’ personal data on the app, and security specialists cautiously noted that not enough was known about Diia's security testing.\nNo independent security audit seemed to have been performed, for example — hardly acceptable for technology to which millions of citizens would be entrusting their personal information. In fact, the app's first public bug bounty program was not launched until December 2020.\nThe leaks have made clear that the standard of data security at the state level in Ukraine remains inadequate — including a weak legal data protection regime, poor enforcement, and the lack of appropriate protection measures within state institutions themselves. Synchronization of data from various government registries into one portal or app is therefore likely to result in additional vulnerabilities to external attacks.\nMoreover, in December 2019, the government granted the Ministry of Internal Affairs the power to verify and aggregate citizens’ data from multiple state registries, providing the law enforcement body with access to data from at least five government registries, including those that handle civil, tax, social security, healthcare and voter information. Alarmingly, the data sharing was to be carried out as a part of an “experimental” process that lacked comprehensive legal safeguards ensuring citizens’ right to privacy.\nAccording to an analysis by digital rights advocates from Digital Security Lab, as of August 2020, the interior ministry had not yet developed a methodology for such verification, but this has not prevented it from gaining access to the vast trove of citizens’ personal data.", "609" ], [ "Is India’s digital ID system, Aadhaar, a tech solution for a socio-economic problem? · Global Voices\nBiometric details being captured in an Aadhaar enrolment centre in Kolkata, West Bengal, India (<PERSON>, CC-BY-3.0)\nThis post was first published on Yoti as a part of <PERSON> Digital Identity Fellowship. It has been edited for Global Voices.\nThe world's largest biometric ID system, Aadhaar, assigns Indians a 12-digit unique identity number which is tied to a range of citizen beneficiary services. The programme was meant to be a technological solution to both existing and emerging socio-economic challenges, designed to help ensure inclusion in India. In practice, however, it has done the opposite, deepening the exclusion of marginal and vulnerable communities.\nAadhaar began to take shape in 2009, when the Indian National Congress (INC) was in government, but saw aggressive implementation under the Bharatiya Janata Party (BJP), currently in office, which holds a majority at the federal level and wields strong influence in many provinces. The system has therefore been used in both federal and provincial public programmes on a massive scale, but exclusion persists.\nIt was hoped that, after a decade of Aadhaar, issues like the country's long history of racial oppression — which existed long before British colonisation and continues long after the country became a democratic republic in 1947 — would be addressed. Instead, many marginalised communities find themselves in a multitude of troubles, unable to access basic amenities and services.\nConversations with members of several such communities — as part of research conducted for the MarginalizedAadhaar project (see Field Diaries #1, #2 and #3) — indicate that the most marginalised among them have been further excluded as a result of the absolute trust in ‘tech-solutionism’ displayed by several state entities.\nHowever, the technological biases that have come out of the systemic social oppression in Indian society — especially in the context of Aadhaar — are yet to be addressed.\n‘Tech-weapons of mass exclusion’\nWhen viewed through the lenses of different demographics — social, political, economic, regional, linguistic, religious, and most importantly, access to privileges for those at the bottom of the pyramid — one can only grasp a tiny portion of what a national biometric-based identity system like Aadhaar means to citizens.\nBy their very nature, ID systems need to allow for social inclusion and the rights of individuals to address issues across the spectrum — from widespread inequality to the nuances associated with the Adivasis, especially the Particularly Vulnerable Tribal Groups. If they do not, people with privileges but with no understanding of diversity and inclusion, end up building ‘tech-weapons of mass exclusion.’\nFor instance, Aadhaar has been deployed for biometric-based authentication in the distribution of food rations through the Public Distribution System (PDS), a federal government initiative that provides food and other essential commodities to those in need.", "607" ], [ "The objective, of course, is to eradicate poverty, but data from the country's census showed that between 2001 and 2011, the number of people in need rose from 21 to 26.8 million, a 22.4% increase.\nContextualising tech\nTechnology, particularly in India, cannot be discussed without bringing up systemic racial discrimination. The country’s political power dynamics are much more racially divisive than ever before, to the point where they have now become part of the apparatus for exclusion.\nThe caste system divides people of the Hindu faith into four major classes, of which some are considered outcasts, or ‘untouchables’. These communities are collectively known as Dalits in progressive discourses; in India's constitution, they are classified as Scheduled Castes (SC).\nThe BJP, the ruling right-wing nationalist party dominated by “upper-caste” Hindus, has been pushing to exclude the Dalit, Muslim and Adivasi people — and several other marginalised communities — through divisive policies. From a human rights perspective, the technological implementations of these policies often translate into inherent and serious design flaws.\nA Muslim woman in the state of Assam who was declared as a “Doubtful Voter” in the National Register of Citizens. (Screengrab from a video reportage by NewsClickin. CC-BY 3.0).\nAccess to information in native languages\nCuriously, in a country where there have been no less than 402 documented internet shutdowns since the BJP came to power in 2014, the Aadhaar system relies on the internet to function. People wanting to get food rations must authenticate their identity via a fingerprint-based process, and authorities at the ration centres use an online portal to verify the information.", "607" ], [ "Syria’s dire economy and years of fighting send young ‘mercenaries’ to fight in Ukraine · Global Voices\nRussian soldiers salute President <PERSON> at Hmeimim Air Base, during a 2017 visit. Russia's airbase in Syria serves as the launchpad from which volunteers are flown from Syria to Ukraine to fight alongside the Russian army. The image is used under a Creative Commons Attribution 4.0 International license.\nThis article was first published by Raseef22 on 19 March 2022. An edited version is published as part of a republishing agreement with Global Voices.\nFollowing years of a devastating war that continues to fragment the country, Syria is now exporting professional mercenaries to other hotspots of conflict, including Libya and the Nagorno-Karabakh region, and they are soon expected to arrive in Ukraine. They packed their fighting experience and headed to foreign arenas, some to fight in Russia’s wars and others fighting Turkey’s foreign wars.\nIts like a Syrian once said: “Blackwater Latakia and Aleppo… Welcome to New Syria”.\nWhen it comes to the recruitment of pro-regime fighters, the name of the Russian private military company Wagner Group stands out. The paramilitary organization has a special contract with the Syrian Defense Ministry to fight inside Syria.\nThe company coordinates with the authorities of the Hmeimim Air Base, Russia’s base of operations in Syria, to recruit Syrians for the purpose of sending them abroad. Wagner’s contractors are not openly present on the scene, but rather operate through a front consisting of Syrians to attract those who are willing.\nSince the start of the Russian war on Ukraine in the last week of February 2022, many people, parties, movements, and institutions came out to say: “We are with you, Russia.” These all collectively came as an echo of the official Syrian position which firmly and resolutely stands with Russia — a position that is understandable in the general political context, as no one expects the Syrian regime to stand against its international ally.\nBut sending “mercenaries” to fight in Ukraine's streets is another matter entirely.", "534" ], [ "It seems that the fighters affiliated with the Syrian regime and the forces that support it have once again set their sights on the dollars that working as “mercenaries” (dubbed “volunteers”) would provide, just like when thousands went to provide support for Russia to face the Turks in Libya. How wouldn’t they, when the USD 700 dollars they were getting paid in Libya per month have gone up to a monthly USD 1000?\nOn March 11, 2022, Ukrainian President <PERSON> said that Moscow was deploying Syrian mercenaries in his country. Russia has not officially confirmed this, but its Defense Minister <PERSON> reported that 16,000 “volunteers” from the Middle East are ready to fight alongside Russia’s allies in the Donbas region in eastern Ukraine.\nThe Middle East here refers to Syria — the only place where Russians have allies ready to embark on a mercenary adventure for political conditions and economic hardships the Syrian war created for its people. Also, Syria is the only place that fighters, logistically, can be transferred from to Russia, through the Hmeimim Air Base.\nRussian President <PERSON> added:\nIf you see that there are these people who want of their own accord, not for money, to come to help the people living in Donbas, then we need to give them what they want and help them get to the conflict zone\nPacking their bags\n<PERSON> is a 28-year-old Syrian man residing in Homs. He packed his belongings in preparation for travel and the subsequent fighting in the Donbas region.\nHe told <PERSON> he is a former fighter from a combat group within the backup forces in the Qalamoun region that was dissolved in 2017, referring to the Qalamoun Shield Forces, an auxiliary military group that isn’t affiliated with the government army but fights alongside it, just like the National Defense Forces, the al-Bustan Association, the Qalamoun Shield Forces, and the Tiger ‘Nimr’ Forces (named after the nickname of Brigadier General <PERSON>).\n<PERSON> recounts how he went to Libya in late 2020 and fought there over two periods. Each period of time consisted of five months, and between the two periods, he went back to Syria for three months.\nHe added:\nNow I’ve been contracted with the Hmeimim Air Base to fight in Ukraine alongside our Russian brothers as a fighter with a salary of 1,000 dollars a month. I do not get the salary while I am on the job, but with my leave to return after seven months, I will receive the full amount for all the months as well as an additional month’s salary.", "328" ], [ "Ukraine: Now That Euro 2012 is Over · Global Voices\nWhen Ukraine was awarded Euro 2012 together with Poland, many saw this as a chance to promote Ukraine’s image as a European country. This, however, has not been easy.\nThe preparations for the tournament were overshadowed by economic difficulties, strained international relations due to the imprisonment of the former Prime Minister <PERSON> (see the GV post here), and a number of other controversies, the most damaging, perhaps, being the allegations of anticipated racism at the tournament coming from the UK media (see GV post here). The negative image stuck so quickly that some entrepreneurs even decided to capitalize on the perception of Ukraine as a dangerous place.\nIn reaction to bad media as well as the perceived shortcomings in preparations on the ground, Ukrainians in the Euro 2012 host cities organized several grassroots initiatives aimed at presenting the country as a welcoming, modern and comfortable place, offering free accommodation, English-language assistance, free tours around Kiev, and help to foreign journalists covering the tournament (see this GV update for details).\nAs the championship culminated in a spectacular Italy vs. Spain match hosted by Kyiv, Facebook users and bloggers gathered and shared impressions of the Euro 2012 experience in Ukraine.\nThus, Facebook user <PERSON> (Олег Пальчик) posted a photo of a grateful football fan from Kharkiv:\nA football fan in the host city Kharkiv with a sign that reads, “Kharkiv, thank you!” in both Russian and Ukrainian. Photo by <PERSON>, used with permission.\n<PERSON>, an England fan, shared some of his experiences of the Euro 2012 in Ukraine on Redbrickpaper.co.uk:\n…The Ukrainian capital and the venue for July’s final, Kiev has been a joy to visit and its people have truly embraced Euro 2012 in every possible way. The daily carnival atmosphere in the city’s huge Fan Zone has epitomised everything that is good about football, bringing people of different nationalities together to enjoy the beautiful game without a hint of abuse.", "910" ], [ "Significantly, we have seen no reason for any of the concerns regarding racism expressed by the British media prior to the tournament. Having seen first-hand the kindness of the locals, their love for football and the excitement that the Euros has brought to their every-day lives, I have drawn the conclusion that everything was blown out of proportion by the press.\nA blogger and Facebook user <PERSON> shared a photo of her apartment where she and her flatmate hosted football fans. She wrote [ru, en]:\nThis is how our apartment looked in the morning)\nWe are friendly girls from friendly Ukraine)\nA photo of football fans hosted by blogger <PERSON> and her flatmate. Photo by <PERSON>, used with permission.\nMany Facebook users and bloggers also shared videos of the Dutch fans singing the Ukrainian anthem in the host city of Kharkiv:\nAdministrators of I Can Help U (speak English in UA) shared a photo of the volunteers of the grassroots initiative “Friendly Ukraine” playing a friendly football game with a team of international fans.\nA football game between the international team of footbal fans vs. volunteers of Friendly Ukraine. Photo by <PERSON>, used with permission.\nAs the championship neared the end, it became clear that the experience of most fans has been rather positive and racism-free, so that some in the British media even began to call for an apology to Ukraine.\nAnd although the latest survey data [ru] shows that the image of Ukraine has not improved with the help of Euro 2012, the grassroots initiatives have certainly contributed to improving the experiences of foreign visitors and left positive memories for many.\nI Can Help U initiative sums it up [ru] by sharing the photo below:\nThis is what it was all for)) !\nGrateful Swedish football fans in Kyiv. Photo by TheVillageEuro2012 Facebook page, used with permission.", "910" ], [ "Who is selling Ukrainians’ personal data online and for what purposes? · Global Voices\nImage by <PERSON>, Pixabay.\nFollowing a number of highly publicized leaks of citizens’ sensitive personal information, Ukrainians are slowly waking up to the importance of data protection. Yet, with the local elections approaching on October 25, a trove of voters’ personal data already available online creates ripe conditions for targeted dissemination of disinformation or any other malicious content by both domestic and foreign political actors.\nIn May 2020, a Ukrainian activist <PERSON> alerted the public about an anonymous @UA_baza chatbot on a popular messaging app Telegram selling personal data of Ukrainian citizens. Appearing only a few months earlier, the bot claimed to have aggregated 900 GB of records including passport numbers, personal identification codes, declared places of residence, driver’s licenses, social media passwords, and even bank details of millions of Ukrainians. It offered access to five entries and the sale of the whole database for 500 USD. The list of available data makes it clear that it could not have only been accumulated from sources openly available online. Then where could this data have come from?\nScreenshot 1: Possible data request options from @UA_baza Telegram bot, including sensitive personal data such a passport number or personal tax number. Screenshot 12.05.2020, account disabled the same day.\nThere are a large number of official and unofficial databases containing citizens’ personal data in Ukraine. Among them state registries compiled and administered by various agencies for the purposes of providing public services, consumer databases, and other datasets of likely commercial nature whose origin is difficult to pinpoint. For example, the State Voter Registry is one of the major state databases containing sensitive information of millions of citizens, which is maintained by a special body within the Central Election Commission (CEC). The access to the Registry is regulated so strictly, that one 2019 Presidential candidate famously complained that it would take him 6,000 years to properly scrutinize it for any irregularities. However, despite apparently stringent security procedures, Ukrainian hacktivists have previously pointed out vulnerabilities of the registry’s website, while CEC members have publicly admitted to the lack of qualified IT/cyber security personnel among civil servants due to a large pay gap between the public and commercial sectors.\nIn turn, commercial entities such as telecommunication companies, online retailers, banks, and logistic operators maintain their own datasets of customer data. Additionally, consumer data is pooled and shared in the framework of several nationwide loyalty programs — some including a network of over 90 online stores and millions of clients across Ukraine. Smaller businesses typically operate their own client databases.", "534" ], [ "While large companies usually only provide access to their data to third parties for advertising purposes, for smaller businesses it is much more common to sell their client databases online. And while the Law on Protection of Personal Data prohibits selling consumer data without the informed consent of its subjects, Ukraine lacks effective regulations and mechanisms to investigate all such instances or hold those in violation accountable.\nThe sheer volume and nature of data made available for purchase on the @UA_baza chatbot prompted a public outcry and an official investigation. The bot itself has promptly gone offline, although it is clear if it was removed by Telegram or deleted by its creators. However, several accounts with a similar name later reappeared on Telegram. A journalistic inquiry into the incident suggested that the leaked dataset combined data from government registries, including older versions of the State Voter Registry and the Unified Demographic Registry, commercial databases, and social media.\nAlthough no one source ever aggregated so much data before, this was not the first time Ukrainian citizens’ personal data were leaked online. In 2018, what seemed to be a database of 18 million clients of the country's largest logistics company “Nova poshta” was leaked. In 2019, law enforcement apprehended someone selling a database of Ukraine’s Customs Service. And in June 2020, journalists confirmed the leak of a client database from PrivatBank – one of the largest banks of Ukraine. Before the appearance of the infamous Telegram bot, such large datasets were sold online on obscure bulletin boards, while a simple internet search would reveal smaller data traders offering to compile custom databases containing full names, telephone numbers, gender, and email addresses upon request.\nScreenshot 2: Possible data request options from an operational Telegram bot offering citizens’ data for sale. Screenshot 15.10.2020\nCome October 25 local elections, the online trade of personal Ukrainians’ data continues. Just recently, a Telegram account mimicking the name of the disabled @UA_baza bot announced it was offering voter databases for sale. And while this account appears to be fraudulent, it is followed by over 16 thousand users. Yet other Telegram bots trading smaller subsets of personal data have been in operation since at least 2018.", "534" ], [ "President <PERSON>’s Controversial Pardon Has Not Put Poles in a Forgiving Mood · Global Voices\nPolish lawyer and politician <PERSON> assumed the office of President in August 2015. Photo by <PERSON>, September 12, 2013. CC 2.0.\nEarlier this month, just a day after the new Polish government was sworn in, President <PERSON> made the controversial decision to pardon <PERSON>, a member of <PERSON>'s former party, Law and Justice.\n<PERSON> was convicted of abusing his powers as head of Poland's Central Anticorruption Bureau, where he served until 2009, during which time the Law and Justice party controlled the Polish government. Before his pardon, <PERSON>'s sentence had not yet entered force, as he was awaiting an appeal trial.\nAlthough the conviction itself was seen as controversial and some considered it a political move made by the previous government (controlled by rivals in Civic Platform), many say <PERSON>'s decision to pardon <PERSON> is surprising and possibly inappropriate. Had <PERSON> lost his appeal, he would have been barred from holding public office ever again, and he may have been sent to prison for many years. <PERSON> currently serves as the head of special services in Poland's new government.\nPolish social media users soon voiced their opinions on Twitter. <PERSON> wrote:\nPrzypominam, że ułaskawienie potwierdza wyrok.", "1017" ], [ "Od dziś o zainteresowanym można pisać per “przestępca”\n— <PERSON> (@konradniklewicz) November 17, 2015\nI want to remind you all that the pardon confirms the ruling. From now on we can call the person in question “guilty”\n<PERSON> also commented on Twitter:\nPAD to chyba zrobił Kamińskiemu krzywdę, bo ułaskawienie nie jest uniewinnieniem. Nie wiąże się z zatarciem. Nie znam się ale to głupie\n— <PERSON> (@FilipLachert) November 17, 2015\nI think that PAD [President <PERSON>] did a disservice to <PERSON>, because the amnesty doesn't mean “not guilty.” It doesn't equal an erasure of conviction. I'm not an expert but I think it was stupid.\nAnother Twitter user, <PERSON>, compared pardons issued by Poland's current and past presidents. As depicted in the picture attached to the tweet, <PERSON>'s pardon was suspiciously just a single sentence long.\nTak na obrazkach wygląda ułaskawienie normalne i ułaskawienie nienormalne: pic.twitter.com/EGi7CXfGBF\n— <PERSON> (@aronsem) November 20, 2015\nOn the attached pictures it can be seen how a normal act of pardon looks like, and how a not normal one looks\n<PERSON> also wrote about the pardon:\nPo to głosowałam na PiS i prezydenta <PERSON> by w moim imieniu ZAWŁASZCZYLI wreszcie państwo , wyrywając je z rąk złodziei i zdrajców\n— <PERSON> (@ISzafranska) November 19, 2015\nThis is why I voted for PiS [Law and Justice] and the Presient <PERSON>, so that they could reclaim the nation and pull it out of the hands of thieves and traitors\nSeveral members of the public complained that <PERSON> has compromised the presidency's impartiality and duty to represent the interests of the nation by indulging in partisan politics. While it's not illegal for the president to pardon a former colleague, <PERSON>'s decision has invited criticisms that he's violated the spirit of his obligations as Poland's leader.\nAlready divided after the elections, Polish citizens continued to be disagree about <PERSON>'s actions.\nPopular blogger and Twitter user <PERSON> posted:\nCoś czuję, że jak będzie za duży jazgot wokół tego ułaskawienia to wkrótce wypłynie jakieś nieznane do tej pory ułaskawienie poprzednika.", "1017" ], [ "Moldova’s youth hope for change from afar · Global Voices\nA man walks past a painting of anxiously waiting parents in Moldova's capital Chișinău, 2014. Photo: Misha_Tokyo / Flickr. CC BY 2.0\nThis article is made possible through a partnership with Transitions, a Prague-based publishing and media training organisation\nThe Republic of Moldova is blessed with a mild climate, bucolic landscapes, popular wine, and empty villages. Moldovans are leaving en masse; their country now has one of the fastest shrinking populations in the world. Poverty, constant political upheaval, and deeply embedded corruption have convinced many to buy a one-way ticket. Some become seasonal economic migrants, returning for a few months every year. Others, many of them highly educated, prefer to leave for good. According to a UNFPA study from 2016 , if no effective measures are taken by Moldova's government to improve the quality of life, in 15 years the country's population, estimated at just under three million, could decline by 24 per cent.\nIt's hard to establish the precise number of Moldovans living and working abroad. The National Bureau of Statistics estimates around 800,000 but the number could be as high as two million when counting those who left the country using another other passports. Moldova recognises multiple citizenships, and many Moldovan citizens can claim an EU passport from neighbouring Romania (both countries were united between 1918 and 1940.)\nAlmost 80% of those who emigrate are between 18 and 35 years old, increasing pressure on the local economy as the working-age population declines. According to the World Bank, 40% of those who migrate have a higher education, contributing to the country's “brain drain.” Much like the country's geopolitical situation, Moldovans’ migration preferences are divided between East and West; 80% of Moldovan migrants are concentrated in three states: the Russian Federation, Italy, and Portugal.\nIn light of recent political changes, now is a good time to consider the effects of this mass emigration on Moldova's domestic politics. Are young Moldovans abroad still committed to fighting for a better future in a country they have left behind? Was emigration for them a sign of resignation in hope of change at home? And does the emigration of the youth rob the country of its chances to push out a discredited elite and achieve lasting change? I spoke to several Moldovans living overseas to understand their perspectives.\n“I am sometimes a bit jealous of these young people in the West who were never confronted with the idea of leaving their countries because they didn't have any future there… I guess it's difficult for them to understand us,” says <PERSON> (pseudonym), a 33-year-old Moldovan citizen who has spent the last decade of her life in Greece.\nEver since losing her mother to cancer at the age of nine, <PERSON> dreamed of becoming a doctor.", "739" ], [ "Years of hard study paid off when she was admitted to the College of Medicine in Chișinău, the Moldovan capital. “I was used to hardship, so didn't expect this new stage to be easy,” recalls <PERSON>, whose two younger siblings remained in her home village. “I still had to take care of them, as my Dad had left for Moscow to support us. I used to work as a nurse for a while, but with a salary of 2,000 Lei (about €100), it was impossible to save anything. So I decided to go abroad.”\nAna's decision to emigrate came several years before Moldova secured a visa-free regime with the EU in 2014. “Getting a work visa for a western country was a hassle, and there were fewer agencies dealing with this sort of issue compared to today. I considered myself extremely fortunate when I got a summer job in Greece. I wasn't doing anything related to my studies but I was paid much more than when I was a nurse in Moldova, so I decided to stay longer and save more. I knew I would become an illegal immigrant but, at that point, I couldn't see any chance of survival back home. Neither do I now, 13 years later,” concludes <PERSON> with a sad smile.\nThis grim outlook, widely shared among Moldovan emigres, has repercussions for their country's electoral politics. According to <PERSON>, a political science researcher at the Justus-Liebig-Univerität in Giessen, Germany, “emigration is ageing both the labour force and the pool of voters. Consequently, the political choices and the electoral behaviour of the older voters shows more reluctance towards progressive views and politicians.", "1010" ], [ "Peace marchers from Helmand look to change Afghanistan’s narrative · Global Voices\nPhoto of the peace march taken from the Etilaatroz news website and used with permission.\nA total of 10,453 civilian casualties — 3,438 people killed and 7,015 injured — were documented in 2017 in Afghanistan. After Kabul, the capital city, it was residents of the southern province of Helmand that had it worst.\nThe #HelmandPeaceMarch movement led by youth from the province tells a story of fatigue from war and spotlights the next generation's search for a better life in a country riven by violence.\nThe march has now reached Kabul, after 700 kilometres on foot through four of Afghanistan's most insecure provinces –Helmand, Zabul, Ghazni and Maidan Wardak. On their way, marchers held meetings with villagers and explained the purpose of their march. They began as 7 people but acquired 59 others over the course of their journey.\nThe Peace marchers’ caravan arrived Kandahar. They moved from Helmand toward Kabul to seek peace and security for their homeland. These dears should be praised and welcomed. Their determination, honesty, and hard-work are admirable. I hope their voice will be heard and they will get the desired result.\nHelmand is a strategic prize for both the government and the Taliban. It is often assumed that the local population of Helmand has reached an accommodation with the insurgents, who control more territory there than the government.\nThe march sought to to defy that stereotype.\nThis rural-born peace movement grew out of a Taliban bombing in Helmand in March left 15 dead and scores wounded.\nFirst, several sit-in tents popped up in Helmand and other provinces: Herat, Nimruz, Farah, Zabul, Kandahar, Uruzgan, Ghazni, Paktia, Kunduz, Kunar, Nangrahar, Balkh, Parwan, Daykundi, Maidan Wardak, Bamyan and Jawzjan. Hunger strikes followed.\nThe march from Helmand to Kabul has four main demands:\n1.", "90" ], [ "Respecting the holy month of Ramadan, all sides of war should declare a ceasefire.(Ramadan ended last week and despite a brief ceasefire, the Taliban have recommenced attacks on government targets);\n2. Specific channels and addresses for peace talks should be identified among all sides of the war, and peace negotiations should be launched;\n3. Considering Islamic and national values and interests, practical steps should be taken for forming a system that is acceptable to all sides;\n4. Based upon the agreement of all sides in this war, a specific timeline should be set for the withdrawal of international forces from Afghanistan.\nThe marchers have been mostly welcomed warmly by people on their way to Kabul. Some even responded to their protest with flowers and songs for peace.\n#Peace Caravan from #Helmand province has just arrived in Shajoi district & they will continue to walk capital #kabul. The have staged a “walk protest” & demanding immediate ceasefire between #Afghan Govt and Taliban.#LongMarch2Kabul pic.twitter.com/9qTiWEdfkm\n— <PERSON> (@engr_raheemi) May 30, 2018\n#Helmand2Kabul and #HelmandPeaceMarch hashtags have widely shared on social media by men, women, boys and girls of all ethnic backgrounds.\n#Hazara #girls in #Ghazni province standing in queue to welcome #Pashtun boys of #Helmand province, who stage nearly 600-km walk calling for peace. The Strong message is “#War & violence do not recognize ethnicity” & Everyone is victim of #violence in #Afghanistan @IntizarKhadim pic.twitter.com/W2YgqkRVA2\n— <PERSON> <PERSON> June 8, 2018\n#Kabul is waiting to host #HelmandPeaceMarch – @ArtLordsWorld is painting a series of murals on the highways leading to Kabul to welcome our #PeaceHeroes #HelmandPeaceMarch2Kabul pic.twitter.com/KrJoz4byz5\n— Omaid Sharifi (@OmaidSharifi) June 4, 2018\nThe Helmand Peace March is in Kabul now. Mom and I went to greet them. They are in front of the Mosque and Madrassa complex facing Habibia School. Seeing them was a moment of joy and healing for mom and me. Let’s welcome them to Kabul with warmth and support.\n— <PERSON> (@ShaharzadAkbar) June 18, 2018\nOn June 19, the marchers met with President <PERSON>, not in the lavish presidential palace in Kabul as officials initially offered, but on the street, where their movement began.", "90" ] ]

[ 8412, 3600, 97, 1144, 5678, 10837, 6314, 2208, 8756, 5427, 746, 5634, 9689, 8907, 1371, 9880, 5873, 1824, 6842, 2791, 11051, 7273, 414, 5139, 835, 843, 4017, 6388, 2710, 2935, 4128, 10153, 7501, 648, 6719, 11308, 9151, 8100, 4106, 8154, 6476, 10509, 2492, 9170, 10939, 9514, 7650, 7275, 8657, 6075, 11061, 1024, 3105, 6729, 3295, 1529, 5284, 8733, 2480, 3981, 6993, 3615, 6571, 3150, 110, 4777, 3398, 6064, 10330, 8317 ]

[ [ "This could be a partial match to Space Prison/The Survivors by <PERSON>. You can find at least some covers here\nIn this story, which takes place over several generations of humans, the protagonists are marooned on a planet called Ragnarok. Ragnarok is a high gravity planet with a very harsh environment, having long very cold winters and very hot summers and a variety of dangerous animals.\nIt turns out that there are two different telepathic animals called \"mockers\" and \"prowlers\". Mockers are:\n... six little animals the size of squirrels, each of them a different color. They walked on short hind legs like miniature bears and the dark eyes in the bear-chipmunk faces ...\n...", "322" ], [ "The two mockers were pleasant company, riding on their shoulders and chattering any nonsense that came to mind. And sometimes saying things that were not at all nonsense, making <PERSON> wonder if mockers could partly read human minds and dimly understand the meaning of some of the things they said\nMockers can telepathically communicate with each-other and can repeat the sounds that another one has heard and telepathically sent to them.\nOn the other hand, prowlers are violent cat-like creatures, who terrorize the marooned people at first:\nThey were things that might have been half wolf, half tiger; each of them three hundred pounds of incredible ferocity with eyes blazing like yellow fire in their white-fanged tiger-wolf faces. They came like the wind, in a flowing black wave, and ripped through the outer guard line as though it had not existed. The inner guards fired in a chattering roll of gunshots, trying to turn them, and <PERSON>'s rifle licked out pale tongues of flame as he added his own fire. The prowlers came on, breaking through, but part of them went down and the others were swerved by the fire so that they struck only the outer edge of the area where the Rejects were grouped.\nThis goes on until one of the survivors helps rescue a mother prowler and her cubs, eventually leading to the \"domestication\" of the prowlers and their eventual use in the defeat of the aliens who marooned the humans on Ragnarok.\nThere seemed no way that men and prowlers could ever meet on common ground. They were alien to one another, separated by the gulf of an origin on worlds two hundred and fifty light-years apart. Their only common heritage was the will of each to battle.\nBut in the spring of one hundred and sixty-one, for a little while one day, the gulf was bridged.", "417" ], [ "I think this might be Dr. Orpheus by <PERSON>. This was published in 1969 and it's the second in a series of books <PERSON> wrote featuring the character <PERSON>.\nDr <PERSON> finds a future Earthworld caught in a double-destructive pincers between benign enslavement by the miracle drug Anagonon and hideous enslavement by invaders from a far galaxy. To meet this twofold threat, <PERSON> must exercise his amazing abilities to the fullest, resorting to time travel, mind transfers, and a breathtakingly swift shell game of body transpositions, all the while battling the greatest odds he has ever faced.\nAs I recall <PERSON> <PERSON> books are all a bit weird even for 1969. The protagonist <PERSON> is some kind of advanced human who can travel in time and occupy different bodies. There is an invasion fleet from the Mandomen Galaxy, though as you say it hasn't reached Earth yet, and the ovipositor bearing aliens are the Myrons:\nThe masculate Myrons of Mandomen Galaxy were a breed that Mandomen mammals found peculiar, although an intelligent insect on Earth (if any had evolved) would merely have found them normal in a different way. Myrons, who were not insects but decapods, had by birth three sexes: male, female, and masculate. The females were the brooders, the mystique centers of clans, the rulers: queens and princesses.", "322" ], [ "The males were the fertilizers, rather stupid, strong in only one respect and otherwise weak.\nThe bracelets behave as you say, and the invaders plan to seize Bracelet One, which controls all the others. <PERSON> defeats the invasion by obtaining Bracelet Zero:\n“Perfectly. But now tell me about Zero.”\n“About Zero?” The German sat up straight. The gynecologist was frowning, puzzled. The other seven merely continued their attitudes of intense involvement.\n“Yes,” <PERSON> insisted. “What about Zero in the Pythagorean arithmetic?”\nBeginning to tremble again, the guilt-ridden psychiatrist ventured: “Zero did not appear in the Pythagorean arithmetic.”\n“Why not?”\n“Because Zero was not known until it was introduced into the algebra by Arabic philosophers nearly fifteen hundred years later—”\n“And if <PERSON> had comprehended the number Zero—what rank would he have assigned it?”\nThe silence was intellectually and emotionally loaded.\nThe German internist fired a reply like a machine gun volley. “The question should be put a bit differently. If <PERSON> had lived today, and if in the light of all our knowledge he had projected his mystical system, which he might well have done: then how would he have ranked the number Zero? I say he would have recognized Zero as the number of psi-space, the number of ancient Egyptian Nun, the formless male-female progenitor of all the gods: the root of our word non. <PERSON> would have accorded Zero a rank higher than One, higher than Alpha—the ultimate rank, with no higher rank possible!”\nThat was when <PERSON> exhibited his bracelet.", "417" ], [ "This is Hothouse by <PERSON>, originally published abridged in the US as The Long Afternoon of Earth. Your description sounded familiar, but I read the book maybe 25 to 30 years ago, so the details were fuzzy. I found a copy at a local bookstore and all the points you remember are in the book.\nIn the book, Earth is tidally locked to the sun and the moon has drifted to one of the Earth-sun Trojan points. The side facing the sun is covered with a jungle formed by a single banyan tree. The story starts with a group of humans, led by a woman named <PERSON>, living in the middle layers of the jungle. The elders of the group \"Go Up\", which is a funeral rite where they climb to the jungle's canopy, and hitch rides on board Traversers, giant plants that have spun webbing between Earth and the moon. The story from there follows <PERSON>, the eldest male remaining, as the whole group gets carried away from the jungle. <PERSON> is banished from the group and has several adventures trying to get back to the jungle. Along the way, he encounters the morel, an intelligent fungus, and the Sodal Ye, the dolphin you remember.\n* The size of the humans: when <PERSON> first meets the morel, the morel tells him:\n\"I know much about humans. Time has been terribly long on this world, and on the worlds in space. Once in a very distant time, before the sun was hot, your two-legged kind ruled this world. You were large beings then, five times as tall as you are now.", "322" ], [ "You shrank to meet new conditions, to survive in whatever way you could.\" (From Chapter 10)\n* The metamorphosed humans are called flymen. They are described as:\nIn some respects they resembled humans. That is to say, they had one head, two long and powerful arms, stubby legs, and strong fingers on hands and feet. But instead of smooth green skin, they were covered in a glittering horny substance, here black, here pink. And large scaly wings resembling those of a vegbird grew from their wrists to their ankles. Their faces were sharp and clever. Their eyes glittered. (From Chapter 3)\n* When <PERSON> and the other elders reach the moon, they have changed into flymen. They meet more flymen, who tell them:\n\"All who make the journey from the heavy world become changed. Some die. Most live and grow wings. Between the worlds are many strong rays, not seen or felt, which change our bodies.\" (From Chapter 5)\n* The dolphin is called the Sodal Ye and is carried overland by a human:\nA giant fish shape, much like one of the dolphins she had seen during their voyage over the wastes of the ocean, had been carried by a stooped old man. (From Chapter 23)", "322" ], [ "I think there is a pretty good chance that you are looking for <PERSON> 1996 novel Reclamation.\nThe story is mainly told from the perspective of three characters. Two are natives of the special planet. One who comes from a high caste ('hand's rather than 'pusher's), has been abroad for a long time, and has established himself as a independent person providing specialized computer and network skills, and the other who comes form the lowest caste and has recently been kidnapped from her homeworld. The third POV character is a member of the Rhudolant Vitae (a space-going humanoid race seeking to reclaim their lost home-world) and serves as the face of the main opponents of the other two.\nThe male native is hired to do an ill-specified job for the Rhudolant Vitae; a job that turns out to be interacting with the female native whom they are holding captive.\nInstead he breaks her out of their custody making some use of his super-normal powers along the way.", "322" ], [ "They separate not long after their successful escape, but not before he guides her through a painful process of overcoming the crippling agoraphobia that seems to be common to their race. Much of the book is spent on his (ultimately unsuccessful) attempts to recover the smooth running of his life after this event and on her continuing efforts to stay out of her captors hands.\nFate brings them all back to the native's world in time, and eventually the natives discover installations of great power and combine their talents1 to employ them to drive back an invasion by the Rhudolant Vitae.\nThe story ends with a powerfully implied spoiler\n! That the native planet is the remains of Earth and the remaining habitable parts are the deepest of undersea trenches, now exposed.\nThe book is a fun and re-readable space operatic romp. Not deep or hugely original, but entertaining.\n1 The details of their talents are another spoiler\n! His talent is the ability to manipulate things, and his caste is described as 'Hand's—a reasonable match for the OP's rememberance of 'push'ing. Her talent is to interface between the machinery and other talents—you may recall that she carried special stones with her and could use them to improve her cognitive recall and organization.", "999" ], [ "Short story about a collector alien that relentlessly chases man stuck on an island\nI am trying to identify the book or the writer that wrote a story that is an anthology of sci-fi short stories from the 1950s, 1960s or 1970s. The anthology was as a hardback.\nAn army man is dropped via helicopter on an uninhabited island, for training I believe. Upon exploration, he is discovers all the sizable animals on the island have had something done to them so that they are in suspended animation, not dead but immobilized and not moving. They are arranged in an exhibition like state.", "944" ], [ "He sees upon an alien (I always imagined it as a big Dalek like thing) that makes a straight line for him and he realizes it is responsible for what happened to the animals. The alien is completely impervious to all his attacks and keeps coming at him, I think with a needle out to collect him.\nThe man panicks and runs off setting traps to crush, stop or block the alien (including a rockfall) but to no avail, he is increasingly panicking and is on the run for 2 to 3 days on the island without sleep trying to stay ahead of the lumbering but relentless alien. We get a cut-shot perspective of the alien which was a robot that an alien race used and released it to collect animal specimen samples of a specific weight range and they left without switching it off. The alien collector has been steadily gaining on the man little by little and finally on the 3rd day, it catches up with the man and just before it attacks, it stops, pauses then it turns and moves on away from him, leaving him alone. The man's helicopter ride comes in and picks him up and the crew is shocked at how bad he looks and they exclaim how it looks like he has dropped 10 pounds of weight in 3 days! He also realizes that the only way to get away from the alien is if you can fly away from the island.\nAnyone know which story this is?", "1012" ], [ "The story is <PERSON> \"The City and the Stars\".\nIt's about how in the past humanity discovered they weren't alone as well as being left behind\nThe story is about the remains of humanity, who decided, more than a billion years before the events of the novel, to remain on Earth when most of humanity left the galaxy.\nhumanity is split on a desert earth with two human remains\nThe story takes place about two billion years in the future, Earth has become a desert save for two places.\none group of immortal people with high tech\nThe people living in the city (Diaspar) live in bodies that are created for them by the city's central computer. The bodies themselves are not immortal, but at the end of their lives, the people upload their memories into the computer.", "240" ], [ "When it's a person time to \"live again\", a new body will be created and, after their childhood, the memories of the person are implanted into the body.\nThe main character is immortal\nHe is an inhabitant of the city.\nnot immortal hippies who are psychic\nThe other place on earth, Lys, is home to \"normal\" humans, who have rejected most machines and are born, age and die naturally. They are telepaths who can communicate without words over great distances.\nThen the races of the universe tried to create a god in the a form of a being made out of magnetic field.\nOver a billion years before the events of the novel, scientists worked on the creation of an disembodied intellect. The first attempt had created a powerful but insane being, the Mad Mind.\nThen that creature killed all of them.\nThe beat the first thing by putting it in a black hole\nIt did not kill all of them (only a lot) before it was imprisoned in a \"strange artificial star\" called the \"Black Sun\".\nbut it got out by going faster than light.\nThe first being is still trapped, but it is hinted, that it would escape eventually.\nBut before they all died they made another one and this one was innocent and stuff.\nThe second being (<PERSON>) was created after the imprisonment of the first being and was created to destroy the first one, which would one day escape its prison.\nand I the end of the book he beats the thing that killed everyone with friendship.\nThis does not happen in the novel.", "322" ], [ "I think this is the book Hosts, which is the fifth book of <PERSON> Repairman Jack series.\nThe possessed girl is <PERSON>'s sister <PERSON>, and the possession is by a virus called Unity that has a kind of hive mind. As you say she is temporarily freed when she uses the microwave though it's <PERSON>'s friend <PERSON> who is first possessed:\n<PERSON> didn’t look at her as she placed her cup inside the microwave and started jabbing the buttons. “What’s wrong—couldn’t see enough through the keyhole?”\nThat stung. “Darn it, <PERSON>, that’s not fair! I’m not snooping on you!”\n<PERSON> turned toward her with a sneer twisting her lips, but then her whole expression changed, flashing from smugness to wide-eyed terror.\n“<PERSON>, oh please, <PERSON>, help me!” she cried, staggering forward against the counter and gripping it with white-knuckled intensity.\nAnd as you say it's because the microwave door is cracked and leaking microwaves:\nHe set the oven for five minutes and started it, then ran the little tester along the edges of the door. The indicator started flashing red immediately and went into high gear when he reached the lower right corner with the cracked glass.\n“That confirms it. Leaky oven.”\nBut at the end <PERSON> constructs a bomb to destroy the virus.", "573" ], [ "There is a propane tank explosion but this is caused by the bomb:\nShe froze her emotions as she picked up the alarm clock. Its two detonator caps dangled on their crudely anastomosed wires against her thighs as she set the timer for 10 P.M. The time was a guess, but an educated one. She’d gleaned enough from the Unity to know that its new meeting place was not close by, and that the mutation to an airborne strain would not be a few minutes’ work. She assumed—prayed—she’d be in their midst by then.\nShe carefully reinserted the detonators into the holes they’d previously occupied, then emptied her shoulder bag and gently settled the assembly into its bottom. A dishcloth from the sink covered the bomb, then the rest of her stuff went back in on top.", "406" ], [ "This is Brother to Demons, Brother to Gods by <PERSON>. Not everything matches your description, but enough matches to make a positive identification.\nIt's set in a distant future where the original humans (the premen) have used genetic engineering to produce new species of humans who have largely replaced them. These new species are the trumen, the mumen and the stargods who are so advanced they are effectively gods. (There are no pi-men or phi-men in the book.)\n* Many parallel universes had been \"mapped\" and some were flagged as fatal to try to enter because they were \"anti-matter\" based.\nThe book opens with:\nThe multiverse creates itself.\nIt had no beginning; neither will it end.\nEach new universe is wombed as a fire-egg, born through a contracting black hole. Expanding in space-time, ripening new black holes, it sows the eternal manifold with new fire-eggs of its own. Cooling, each new cosmos gives birth to galaxies and suns, to worlds of life and change, sometimes to intellect.\nand we find that half these universes are anti-matter:\n\"One word of warning.\" The piercing squeak cut him off. \"If you ever find your way to another universe, enter it with caution. Half the early cosmic explorers never came back, because they weren't aware of a law of symmetry that rules the multiverse. Every alternate space-time expansion produces antimatter.\"\n* One of the characters was a dwarf-like human who chose to be ugly\nThe ugly dwarf is <PERSON>, who is one of the gods but who is deformed because he's the result of an experiment that went wrong.\nThe creature stood perched on a high sandstone bench, peering down at them with a single bright green eye. Less than half human, it looked monstrous. Its arms and shoulders were immense, the lower body dwarfed, giant hands brushing doll's feet. Naked except for particolored fur, yellow-and-black, it seemed sexless. The head was pink and bald and baby like, the left eye squinted shut, white teeth flashing through an impish grin.\n...\n\"I'm a god—a botched god.\" With a startling show of power, it bounded off the floor and dropped lightly onto a tabletop before them. \"A failed creation.\" The fat pink face grinned wryly.", "322" ], [ "\"Though the Creators were rebuilding their own genes from generation to generation, they never fully overcame their preman limitations. Sometimes they blundered. When old <PERSON> set out to make the stargods, his first attempts went badly wrong. Most of them had to be destroyed—often in haste. I was more fortunate.\n* Another character was a woman/goddess who was bored with society and went on \"vacation\" to explore other universes.\nOne of the characters is described as A lovely young goddess, touring the sacred sites of her ancestral Earth though I don't think we ever learn her name or indeed much about her.\n* Some of the sub-humans had designations like \"Mu-Men\", \"Pi-Men\", and \"Phi-Men.\" Each greek letter had different abilities and purposes. Some were used in gladitorial combat arenas for entertainment. Others were pets or bodyguards.\nAs noted above there are premen, mumen and trumen, but no pi-men or phi-men.\n* The characters accidentally stumbled on our universe by accident. Our universe was incorrectly mapped as an anti-matter universe.\nIt isn't our universe that was incorrectly mapped, but a universe like ours. It was found by <PERSON> by accident:\n\"They'll never find us,\" <PERSON> whistled. \"It's a place I discovered myself, but only by an accident I'm sure they won't repeat. On the way here Zhondra was giving me a lesson in transvolutionary navigation. By what should have been a fatal mischance I skipped the ship through a forbidden discontinuity, into a universe that had been charted as antimatter—\"\n\"Oh—\" <PERSON> gasped.\n\"But it wasn't.\" <PERSON> gave her his impish grin. \"We didn't die. It turned out that the charts were wrong. Before we got out, Zhondra had located a Sol-type sun with at least one friendly seeming planet.", "322" ] ]

[ 6183, 7781, 2191, 6167, 8101, 3483, 9809, 1631, 11070, 11166, 10328, 9857, 8538, 6177, 3569, 10882, 4904, 10857, 8413, 1573, 11285, 4392, 7528, 3374, 6061, 9900, 11298, 9197, 4232, 7149, 11247, 1550, 10826, 6788, 7579, 7423, 2159, 4323, 3628, 9459, 5932, 6662, 11044, 1179, 3736, 10888, 5157, 772, 2286, 10459, 1925, 1007, 8219, 8824, 1798, 6275, 9805, 6361, 10608, 2641, 2231, 2495, 8157, 7739, 9998, 23, 5266, 4203, 694, 7527 ]

[ [ "Can <PERSON> planet actually exist in our universe?\nThis is a drawing by my daughter which inspired one of the elements in my story/world:\nThe perspective is a little bit mixed here (certainly I don't have a 15 meter-high volcano in this world), but for the sake of this question let's assume that such planet is between 1 and 2 kilometres in diameter or 500-1000 meters in radius. Planets like this are sold by various agencies in the world of my story.\nGiven the fact that the whole story is set in exactly the same universe, as ours (only a little bit into the future), with exactly the same physics and other laws, the question is, if such planet:\n* could exists naturally (what are the limits here) or\n* these companies are selling artificial creations.\nWhat is the smallest possible planet that can exists naturally in our universe? Must I assume that such small planets cannot exist naturally?\nEdit: Here are some answers to the questions given in comments. In short, think about compressing Earth to as smallest size as our current physics allows.\n1. The planet must be habitable, with gravity as close to Earth's one as possible.\n2. Any round rock orbiting the sun or other stellar body does the trick. Meeting IAU's or other definitions is not needed.\n3. Buildings required. Other stuff as well. Full recreation of Earth's look & feel very welcome. This should be private planet as we now understand a private island.\n4. Escape velocity and other physical, chemical or geological parameters as close to the Earth as possible. So, again, a rock in space, not a small gas body.\n5. Again, circling the Sun or other stellar body.", "710" ], [ "No comets lost in space, please. Light and day-night conditions and yearly seasons as close to Earth as possible, please.\n6. No rain, snow or clouds needed, though nice to have. Breathable atmosphere is a must.\n7. This should be a habitable planet, but for a single person or a small group of people. As you can see in the image, we don't need more than 3-5 story buildings. So the fact that breathable atmosphere would be as thick as 500-1000 m above the ground isn't necessary a problem.\n8. Extremely dense core sounds like a good idea, but that might ruin the \"as close to Earth physics as possible\", if I am not mistaken. And it would also most likely fail under \"habitable\", as we would need some underground water sources etc.\n9. A black hole in a center of a planet certainly sounds good as long as above conditions are met.\n10. Asteroid might work as well as long as above conditions are met.\nThe planet must be habitable and easily accessible. So, if by any mean, planet's atmosphere would be filled with some orbiting rocks or other space trash, disallowing any easy navigation and landings, then this is out of question.\nThe company wants to sell a fully-featured product, where you can spend the rest of your life. Not just a rock in space, that you can show off on your pictures, but that you cannot land on and live on.", "591" ], [ "Atmospheric pressure in an almost empty world with a specific habitable zone far above the ground\nI'm currently working on the following concept of a world for a high fantasy setting:\n* The world's core has a radius of around 100 km. Inside is a magical object that creates a large-scale (planet-sized) gravitational field around it.\n* The core is enveloped in a mantle of around 10-15 km of water with no additional notable land masses, such as continents.\n* The \"habitable\" zone begins at around 8.000-9.000 km away from the core. This is where humans and humanlike species live under conditions similar to earth's sea level (same air composition and pressure, gravitational constant of approximately 10, etc.) on magical floating islands.\n* No other celestial bodies exist in the universe, as sun, moon, and so on are divine constructs (comparable to e.g.", "710" ], [ "<PERSON>' chariot from Greek mythology).\nWith the basics out of the way I'm wondering about certain properties (especially relating to atmosphere and pressure as these are some of the most difficult topics for me personally) this world would have and how they could be explained with something other than \"it's magic\"? I don't require any hard numbers, I'm just very curious about what parts of this concept could be explained sensibly with the help of science.\n* How high is the approximate pressure inside the water mantle and below the inhabited zone. Could any realistic creature survive inside it? Could the water physically even be liquid?\n* How large would the \"habitable\" zone be? Just as earth's atmosphere gets too thin for humans to breathe above a certain height, how dense would this much larger atmosphere be at bigger heights? Would the pressure fall-off be linearly compared to earth's atmospheric pressure (e.g. a constant factor of x times earth's pressure for any given height or would this factor be changing depending on height)?\nThis is my first question here, so I'm very sorry if I made a mistake while asking this question! Please tell me if I did so and I'll try to correct it!\nThanks a lot in advance!\nEdit: I forgot to mention that the magical object at the core generating the gravity creates it in a manner as if it was an extremely high amount of mass condensed into a small point.\nI also went a bit overboard with the block of questions, sorry. I would summarize them as \"Given the setting above, how would pressure affect habitability and atmospheric composition at different altitudes, assuming otherwise realistic physics?\"", "710" ], [ "Creating a stable, liveable ringworld orbiting a binary black hole/stellar pair\nI'm creating a setting for a sci-fi RPG. I would like to check whether the concept is physically possible. The main action happens on a giant ringworld which centrifugally orbits a paired black hole and star. Here is a diagram of what I mean:\nI am hoping that this setup would provide a day-night cycle. When the star is visible from a point on the ringworld, it is \"day\". When the star goes \"behind\" the black hole, it becomes \"night\".\nConstraints:\n1. The ringworld orbit should be stable.\n2. The star orbit around the black hole should be stable - ie the star is not feeding the black hole (due to radiation issues) and therefore there is no accretion disk.\n3. The radius of the ringworld should be reasonable - between 0.1 - 2 AU.\n4.", "24" ], [ "The mass of the star should be reasonable, erring on the smaller side\n5. The mass of the black hole should be reasonable, erring on the smaller side\n6. The irradiance (watts of radiation per square meter) on the ringworld should be comparable to that of Earth.\n7. The wavelength profile of the irradiance on the ringworld should either: be comparable to that of Earth (preferable) or if the black hole generates insanely dangerous gamma rays (reduced due to no accretion disk?), it should be at least plausible that the ringworld has some sort of magnetic field generation technology powerful enough to deflect them.\n8. The orbital period of the star around the back hole should be comparable to that of a day. Anywhere between 12-48 hours would work though.\n9. Something also to consider: the day/night cycle will break down if the black hole Schwartzchild radius is smaller than the radius of the star. So the radius of the black hole has to be greater than the radius of the star. I imagine this will require a black hole of considerable mass. This can be scifi'd away with \"inertial dampeners\" in the ring or something if required.\nIs such an orbital setup mathematically possible without leading to an absurdly large ring?\nThanks!", "24" ], [ "Would a mini-blackhole collision with Earth cause destruction?\nLet's forget about the probability of this event. I am a mad scientist on the Moon, I created a micro black hole of the diameter $r=0.5cm$. I have to be fast before it evaporates due to Hawking radiation, but before shooting it to the Earth, doubt stops me.\nAs soon as my blackhole reaches the ground (and even before), it starts sucking material. Everything it \"touches\" would disappear under the event horizon. It couldn't create shockwaves and alike. How could then it produce the massive blast of heat and destruction it supposed to?\nI consider two scenarios:\n1. The black hole travels to the Earth with relatively low speed. This way the (zero) momentum of the material it sucks during interaction would slow it down enough to finally stop. After that, it would slowly but surely consume the whole Earth. This is the less interesting problem therefore.\n2.", "483" ], [ "The black hole hits Earth with a significant portion of light speed. It wouldn't even bother with the sucked material, even the whole planet couldn't stop it. Speaking of an asteroid, this would be the holly way of total destruction. But I have an event horizon...\nSo, there is the question:\nIn both cases, would it, and if, by what effect and how much would the black hole heat up the impact zone?\nI have some theories. Maybe the gravitational turbulence the encounter causes locally would cause enough heat to be destructive. This seems to work only for the first case: a speeding hole would have little time to accelerate the ground material. Maybe the material it sucks up would emit strong enough radiation. Or the collision's energy would indeed only increase the black hole's mass, and I would only get a neat 0.5cm wide hole in the ground with slowly (?) rising diameter. (In this case, I'd wonder if any friction-like phenomena would occur apart from the momentum of sucked material...)\nNote: I am not interested in the effects of Hawking radiation of the black hole, though I don't know how significant would it be. If it is so big it makes the neglection unrealistic, feel free to produce a bigger mini-blackhole.", "912" ], [ "Questions about the potential characteristics of a hypothetical Planet 9\nSo, I'm writing a story. Most of the main story is set near Planet 9, which has finally been found somewhere far out in the outer solar system.\nSo first, I’ve been working on determining the probable characteristics of Planet 9.\nIn line with predictions, it’s an ice giant (a gas-rich sub-Neptune composed of an icy-rocky core with a H-He rich envelope) which is approx 7 earth masses.\nThe most recent article I can find on the topic from <PERSON> and <PERSON> seems to predict that Planet 9’s perihelion is likely 340(+80/−70) AU, that its aphelion is likely 560(+260/-140) AU, and that the semi-major axis is 460(+160/-100) AU. Unless I am sorely misunderstanding this paper (and I could be), the numbers provided seem to be a range of numbers which they think Planet 9 could fall into.\nhttps://iopscience.iop.org/article/10.3847/1538-3881/ac32dd/pdf\nI’ll assume that the perihelion is 340 AU and that the aphelion is a bit further out - 750 AU.\nThe semi-major axis is half of the major axis, which is the sum of the perihelion and aphelion.\nSo semi-major axis = (perihelion+aphelion)/2.\nThe orbital eccentricity is the ratio between the difference and the sum of the perihelion and the aphelion.\nSo eccentricity = (aphelion - perihelion)/(aphelion + perihelion).\nSo, after crunching the numbers based on these initial assumptions: Its perihelion is 340 AU, its aphelion is 750 AU, its semi-major axis is 545 AU, and its orbital eccentricity is 0.38.\nNow, in order to estimate the orbital period, I’ve applied <PERSON>’s third law of planetary motion for a quick back-of-the-box calculation. If we measure the period (T) in years and the semi-major axis (a) in AU we can use a^3 = T^2.\n545 cubed is 161,878,625.", "710" ], [ "The square root of that gives us an orbital period of approximately 12,723 years.\nI have a few concerns. I'd like to know if my numbers are solid here, and if they are consistent with Planet 9's hypothesised characteristics given what we know.\nFurthermore, I'm planning for it to have two main moons. One is approximately the size and mass of Ganymede, with similar gravity, whereas the other is the size and mass of Charon.\nI have no clue if I can give it moons that large and still have it remain consistent with their models for Planet 9, but I’m unfortunately not well-versed enough in this to tell. If someone could help with this, that would be fantastic.\nFinally, I have a question regarding how to calculate its diameter. I'm not yet sure how I would yet go about doing that.", "710" ], [ "An infinite train circling the planet that never stops\nAs a way to travel fast, my Earth-like planet is going to have a special train, circling it (the axis of the 'tracks' is aligned with the planet's axis of rotation).\nThe thing about this train - it never stops and it doesn't end - there is no first or last car, they are all joined in a circle.\nMoreover, it's actually several trains, going parallel to each other. The first one travels at the speed of 5 km/h, such that any healthy person can get on it. Then the second train travels at 10 km/h, and they are close enough so it's no trouble to step from one to another. The next travels at 15 km/h, the next at 20 km/h, etc.\nI think about 200 trains should be enough to provide the means of fast travel around the planet. Of course, there is the matter of travelling to and from the tracks. As for the 'other side of tracks, we just need a second set of slower and slower trains.\nThe problems with this concept:\n* Safety of the passengers. If all the trains function perfectly, then we just need a system of safeguards in place so no one could possibly fall down or injure themselves while stepping between the trains.", "947" ], [ "At the speed difference of 5 km/h even if there are some inner walls or support beams, it still should be safe enough. Now on the other hand, if there is some malfunction, the inertia could kill everyone in the fast moving trains.\n* Long time functioning of the train. To get rid of friction we could use magnetic tracks (or even tunnel), but it will take a lot of energy. On the other hand, is it possible to use centrifugal force from the fast trains to support the whole structure? How fast should they move in this case (we can make the inner cars heavier than the outer ones)?\n* What other problems could arise? Interaction with the planet's magnetic field, air resistance currents, etc?\n* Possible means of building the train: the materials (maybe carbon fiber, like space elevators?), the power, the infrastructure?\n(!) Important! The only thing I'm handwaiving is the tracks construction. Let's say we somehow managed to do it, despite the mountains, bodies of water, etc. Maybe under the surface, but I won't elaborate further.\nI hope the question is not too broad, I will accept partial answer as well. Probably the only question: how to make this means of travel feasible?\nI want to make this believable enough so the real fun about the societal implications could start. Can you imagine working as a conductor on this train?", "199" ], [ "Please help me calculate acceptable planet sizes & eclipse shadows cast by my binary planet system\nI've been reading here for a little while, but this is my first question. I am trying to come up with either a concrete set of numbers for a single answer for a binary planet system, or a simple formula that allows me to play within a range of acceptable numbers that answer my question. Math and I don't really get along anymore, so the less complex your solution, the better. Even a solution via simple 3D modeling / illustration on spheres or geometric drawings is welcome if it also provides numbers that fulfill the solution.\nALSO I'd like to keep this within the realm of plausibility, so sources for creating my system are listed after the question. I don't mind if the science pushes the boundaries of what we know. Unusual, rare, unlikely, and unique solutions are welcome; impossible ones are not.\nHere are the shadows I'm trying to achieve:\nFigure 1: The two possible shadows cast by each planet when all three bodies are in alignment\nI'm going to leave my inaccurate drawings above for now because they better illustrate the landmasses and ocean areas on both planets. I'll replace them when I'm able. More accurate yet simpler sketches below along with (hopefully) improved wording.\nRequirements:\n1. Binary planets (tidally locked to each other) orbit an M0 parent star at the outermost edge of its habitable zone. (See note1) Neither planet, nor the binary system as a whole, supports a moon.\n2. Both of these planets must be theoretically capable (liquid surface water / atmosphere / pressure / mass / density-wise) of supporting a range of humanoid and other life forms (akin to <PERSON>'s world, minus mankind as an example), and share biomes.\nThey must not be closer to each other than 3 times the radius of Planet B. (See note2)\n1. Planet B must be larger than Planet C and not be wider than 12000 km in diameter (slightly smaller than Earth size); however, I strongly prefer Planet B to be as small as possible within the given constraints.\n2.", "710" ], [ "Planet C must not be smaller than 6000 km in diameter. (See note3)\n3. During A-B-C alignment (Fig 1)\n- A being floating in the center of the night side (it's in the middle of the ocean) of Planet B (point b) will see only a circle of darkness blocking the stars (behind Planet C) when looking toward Planet C. (Fig 1a) Planet C should fall well within the umbra cast by Planet B.\n- A being standing at point c will see a total eclipse of Star A by Planet B when looking starward. Only the corona should be visible (Fig 1b)\n1. During A-C-B alignment, (Fig2)\n- A being standing in the center of the night side of Planet C (point c) will see Planet B as a thin blue ring – with an apparent width not wider than 1/6 the radius of Planet B – with northern polar ice visible. More temperate landmass may be visible closer to the northern side of the equator.(Fig 2a)\n- A being standing at point b will see an annular eclipse of Star A by Planet C because Planet C is not large enough to eclipse it totally (Fig 2b)\n2. Rotation period for the two planet system should not be less than 16 hours nor more than 64.\nIs this plausibly realistic?\nI simultaneously hope this question is not too long and that I've provided enough info. If not, please me know what I can to do improve.\n(note1) ~0.5 solar masses. See Habitable Planets for Man by <PERSON> (second edition) American Elsevier Pub. Co. - 1970 pg. 81. “For a special rare class of planets with extremely large or close satellites, there is an extension of the lower permissible primary mass [of the parent star] down to 0.35 solar masses.” My star falls well with this range, and the binary planet system fulfills the large/close satellite requirement.\n(note2) Can binary terrestrial planets exist? at Phys.org\n(note3) Jim2B’s wonderfully detailed answer to Worldbuilding question Smallest possible habitable planet? (also taking density into account)", "371" ], [ "Could a Giant Earth planet have lower gravity than Earth?\nI'm writing a neo-pulp adventure and one of the planets that appears needs to have the following characteristics:\n* Is populated by giant non-sentient non-humanoid insect-like aliens, some from the sizes of cattle but some from the size of a Boeing 747. Some of the bigger creatures should be able to fly.\n* The atmosphere is very thick and most of the planet is very jungle-like like a rain forest.\n* The flora is not so Earth-like, there are no trees, but plants with flowers can grow taller than redwoods.\n* There will be one type of spider-like creature that creates something similar to a spider web but strong enough to capture a small flying vehicle. Thus this creature should be able climb plants.\nNow I was thinking that for many of these characteristics it should have lower gravity however I'm not sure if is physically possible for a rocky planet some N times Earth's size to have lower gravity.", "922" ], [ "I know that a planet's gravity has to do also with density and not only size, but again, not sure if a rocky planet can not be dense enough to have lower gravity than Earth. Another possibility is to make the opposite, a planet with high gravity with its fauna adapted to it, however in that case I doubt flight will be possible.\nKeep in mind that: * Earthlings (as I'm not using the term human) are not going to stay there for much longer, just a couple of days, weeks at most. * If Gravity is higher than Earth it should not crushed humans and human-size aliens that arrive there, but can cause some discomfort.\n* Technically is not necessary for it to be a super Earth, even an Earth-size planet is still huge but if possible to keep this will be more fun. * Is preferable that the atmosphere is human-breathable.\nThanks in advance.\nPD: Is a neo-Pulp novel so is certainly not hard sci-fi, science doesn't have to be rigorous (although some scientific accuracy doesn't hurt anyone) but the point is it's soft sci-fi as long as avoids magic or fantasy explanations will be enough.", "947" ] ]

[ 9399, 10424, 4685, 10000, 8326, 10701, 4020, 4725, 7631, 1789, 10217, 706, 1088, 10478, 6843, 10449, 6776, 5432, 10819, 9842, 10776, 2984, 994, 2134, 273, 6187, 8174, 11015, 223, 8441, 8028, 9216, 4427, 7523, 11174, 10187, 2256, 10419, 5311, 2594, 4252, 5105, 8459, 3483, 9985, 8181, 5527, 10909, 9554, 2579, 1877, 5573, 2726, 10928, 7809, 8950, 8811, 4904, 1339, 5360, 7162, 4323, 6561, 3569, 411, 7609, 10999, 9079, 1753, 3328 ]

[ [ "4-Wire Horizontal Plotter\nIntroduction: 4-Wire Horizontal Plotter\nThis instructable explains how to make a 4-wire plotter using the wheel-rims from a toy car, four stepping motors, a scrap of sheet aluminium, some pulleys, and an Arduino UNO R3.\nUnlike 2-wire vertical plotters the drawing surface for this plotter is horizontal.\nConstruction is simple:\n* the “base” requires a ruler, a few drills and a saw.\n* the “gondola” requires an electric drill, a set of circle cutters, and a sharp knife.\nFeatures include:\n* an on-board interpreter that recognizes the g-code output from “Inkscape”.\n* accurate ... approximately 1mm with nylon\n* scaleable ... just increase the cable lengths\n* easy to make\n* low cost\nThe estimated cost of parts, excluding the power supply, is less than $100.\nImages\n* Photo 1 shows a close-up of the plotter\n* The video shows the plotter in action\nStep 1: Parts List\nThe following parts were obtained from https://www.aliexpress.com/\n* 1 only Arduino UNO R3 + USB cable\n* 1 only SG90 servo\n* 4 only 12VDC Nema17 17HS3430 stepping motors\n* 4 only NEMA 17 Motor L-mount stepping motor brackets with screws\n* 4 only 2A per phase Big Easy Driver v1.2 A4988 stepper motor driver board\n* 4 only 65mm RC Car wheels with tyres on 50mm drums (see photo 1)\n* 4 only hexagonal brass couplings with 5mm bore to fit the motor shafts and a 4mm hole for attaching the wheels.", "16" ], [ "The short ones in photo 1 are satisfactory.\n* 4 only miniature V624ZZ pulleys with V-groove size 4*13*6mm\nOptional:\n* 1 only CPS-3205 Compact Mini Variable Adjustable DC Power Supply 0-32V 0-5A AC110-240V (not required if you already have a 12 volt 2 amp DC power source)\nThe following parts were obtained locally:\n* 1 only sheet of 6mm composition board approx. 800mm x 600mm\n* 1 only length 60mm x 20mm timber for corner supports\n* 1 only reel of 0.5mm diameter nylon fishing line\n* 1 only switch\n* 1 only MBR735 diode for reverse voltage protection\n* 1 only pkt of assorted Arduino jumper cables\n* 1 only scrap of thin acrylic sheet for gondola annular ring\n* 4 only M3 threaded Nylon spacers for supporting the acrylic annular ring\n* 1 only scrap of thin sheet aluminium for pulley mounts\n* 4 only M3 x 9mm tubular spacers for pulleys\n* 12 only wood screws for assembling corner supports\n* assorted M4 nuts and bolts to suit your particular build\n* assorted M4 nuts and biolts to suit your particular build\nThe estimated cost of parts, excluding the power supply, is less than $100.\nStep 2: Circuit Diagram\nPhoto 1 shows the circuit diagram of the 4-wire plotter.\nThe Big Easy Driver “direction” lines are on Arduino PORTC pins A0, A1, A2, and A3\nThe Big Easy Driver “step” lines are on Arduino PORTB pins D8, D9, D10, and D11\nThe SG90 servo “control” wire is connected to pin D3\nThe MBR735 diode provides reverse voltage protection.\nMotor Wiring\nIt may be necessary to reverse the two center wires from each of the 17HS3430 Nema17 12 volt stepper motors as the Big Easy Driver v1.2 A4988 stepper motor driver boards expect the wires from each of the coil-windings to be adjacent.\nThe default color sequence for the 17HS3430 cables (for my motors) is red, blue, green, black. The color-sequence following the modification is red, green, blue, black.\nThe red, green winding is connected to the “A” terminals of the Big Easy Driver.\nThe blue, black winding is attached to the “B” terminals of the Big Easy Driver.\nBig Easy Driver Current Limits\nThe current-limit on each of the Big Easy Driver must be set to 400mA (milli-amperes) .", "611" ], [ "CNC Plotter\nIntroduction: CNC Plotter\nThis Instructable explains how to build a CNC plotter, using two NEMA17 stepping motors, a timing belt, a few idler pulleys, an Arduino UNO R3 microcontroller, and some printed PLA parts.\nThe paper size is A4 ... longer pipes are required for A3\nResolution is 80 steps per millimeter.\nUnlike some plotters, in which the arm moves back and forth, the footprint for this plotter is constant.\nA mounting base is not required as the plotter is freestanding. Screw-holes, however, have been provided should you wish to add a base.\nThe design is such that a laser print-head (future project) can be substituted for the pen-lift shown in photo 1. The current design is used for creating watercolor outlines.\nThe detachable pen-lift is described in my instructable https://www.instructables.com/CNC-Pen-Lift-1/\nThe plotter runs a modified version of “GRBL- Servo” and works with “UGS” (Universal G-Code Sender).\nThe timing-belt path is unusual in that the belt passes through the inside of the 12/10 diameter metal arms. This accounts for its simplistic look.", "16" ], [ "The belt is tensioned by moving the end-brackets outwards.\nConstruction details, including all STL files, are provided … … all you need is a screw-driver, a pair of side-cutters, and a hacksaw.\nExcluding the CNC-Pen-Lift, the estimated cost of this plotter is less than $100\nImages\n* Photo 1 shows the assembled plotter\n* Photo 2 shows a sample plot\n* The video shows the plotter in action\nSupplies\nThe following parts were purchased from https://www.aliexpress.com/\n* 1 only Arduino UNO R3 with USB cable\n* 2 only Big Easy Driver motor controllers\n* 2 only 12 volt 30 ohm 17HS3430 NEMA17 stepper motors\n* 2 only NEMA17 stepper brackets\n* 1 only 3m length GT2 6mm timing belt\n* 2 only GT2-20 6mm timing pulleys with 5mm bore\n* 3 only GT2 6mm toothless idler pulleys with 4mm bore\n* 4 only GT2-20 6mm toothed idler pulleys with 4mm bore\n* 6 only LM12UU linear bearings\nThe following parts were obtained locally:\n* 2 only 1m lengths 12/10mm (O.D./I.D.) metal tube [1]\n* 8 only M3 x 5mm bolts\n* 4 only M3 x 10mm bolts\n* 4 only M3 x 20mm bolts\n* 4 only M3 x 35mm bolts\n* 4 only M3 nuts\n* 15 only M4 x 30mm bolts\n* 15 only M4 nuts\n* 2 only cable ties\nIn addition to the above parts your will need to make the pen-lift described in my instructable https://www.instructables.com/CNC-Pen-Lift-1/\nYou will also need to print the PLA parts described further on\nExcluding the CNC-Pen-Lift, the estimated cost of this plotter is less than $100\nNotes\n[1]\nI used 12mm O.D. aluminium tube\nAluminium tube was all that was available at the time … (stainless steel would be better)\nStep 1: Circuit\nThe wiring diagram for this plotter is shown in photo 1.\nIMPORTANT - the Big Easy Driver modules expect the wires from each motor coil to be adjacent. Check that the motor wires don't alternate ... if so swap the two center wires.\nAdjusting the motor current(s)\n* Attach a 12 volt 30 ohm NEMA17 stepping motor to a Big Easy Driver module and apply 12 volts DC to the motor assembly. [1]\n* Now adjust the small potentiometer on the Big Easy Driver module for a current reading of 0.4 amps\n* Repeat this process for the remaining motor and Big Easy Driver module.\n* Disconnect the power.\nSubstitute motors\nThe plotter also works with 6 volt 8 ohm stepping motors in which case a 6 volt power supply should be used and the motor currents set to 0.6 amps (600mA).\nNotes\n[1]\nI’m using a CPS-3205 adjustable power supply which has on-board metering. Any 12 volt power supply/battery capable of 2amps will work equally well … just insert a current meter in series when adjusting the current.", "16" ], [ "CNC Graphics Tablet\nIntroduction: CNC Graphics Tablet\nThis instructable explains how to make a CNC graphics tablet from a 4-wire resistive touchpad and an Arduino UNO R3 microcontroller.\nA gcode file is created for each of your drawings. [1]\nConstruction is simple ... all you need is a steel ruler and a sharp knife.\nThe tablet supports both freehand and point-to-point drawing.\nThe touchpad has a resolution of 600 x800 pixels which translates to a 600mm x 800mm drawing if your target resolution is 1mm/pixel.\nThe estimated cost of construction is less than $25\nImages\n* The cover photo (photo1)shows the completed tablet.\n* Photo 2 shows a magazine cover under the tablet\n* Photo 3 is a close up of the tablet\n* Photo 4 shows the freehand tracing\n* The video shows the tablet in operation\nNotes\n[1]\nThe tablet is intended for use with CNC plotters ...", "16" ], [ "not CNC mills.\nStep 1: Parts List\nPhoto one shows all of the parts needed to build this tablet.\nThe following parts were obtained from https://www.aliexpress.com/\n* 1 only 8 inch, 183*141mm (4:3), AT080TN52 V1 4 Wire Resistive Touch Screen Panel\n* Resistive Touch Screen Panel\n* 1 only Arduino UNO R3 microcontroller with USB cable\n* 4 only 100mm male-to-male Arduino jumper wires\nThe following parts were obtained locally\n* 2 only 23cm x 26cm pieces of mat-board from a picture-framer\n* 8 only M3 x 5mm bolts\n* 4 only 9mm x M3-threaded nylon spacers\n* 1 only roll of cloth tape\n* 1 only roll of doubled-side tape\n* 1 only wooden toothpick\nThe estimated cost of construction is less than $25\nStep 2: Circuit\nPlace the touchpad face-up and connect the Arduino pins A0, A1, A2, and A3 as shown.\nDo not cross the male-to-male jumper wires\nStep 3: Theory\nThe 8 inch 4-wire resistive touch-screen comprises two resistive films that are separated by an 800 x 600 array of microscope insulators.\nEach resistive layer has two leads\n* The Y-axis has one lead connected to the top-edge and one lead connected to the bottom edge.\n* The X-axis has one lead connected to the left- edge and one lead connected to the right-edge.\nPressing on the top surface causes the two films to make contact.\nY-Axis Measurements\nFor ease of explanation let’s assume that the bottom layer is the Y-axis and that the Y-axis leads are connected to a 5 volt DC supply.\n* The resistive film acts like a voltage-divider.\n* The voltage at the bottom will measure 0 volts,\n* the voltage at the center will measure 2.5 volts,\n* and the voltage at the top will measure 5 volts\nTo measure this voltage we connect a lead from the top film to an analog input such as A0 , then press the top layer with a stylus to make a connection. [1]\nWhen a connection is made the Arduino analog-to-digital (A/D) converter will output a number between 0 and 1023\n* 0 volts equates to a reading off 0\n* 5 volts equates to a reading off 1023\n* 2.5 volts equates to a reading of 2.5/5*1023 = 512 (rounded)\nThese numbers can be converted to Y-coordinates using the following Arduino code:\nYpos = map(y, 61, 958, 0, 800); ................................................................ (1)\nwhere\n* 61 = actual value when the bottom of the screen is touched [2]\n* 958 = actual value when the top of the screen is touched [2]\n* 0 = the lower screen coordinate.\n* 800 = the top screen coordinate.\nX-Axis Measurements\nSimilarly the X-coordinates may be found by applying 5 volts across the X-axis leads (top-layer) and measuring the A/D values with one of the Y-axis leads.\nIn this case the X-coordinates may be found using the following Arduino code:\nXpos = map(x, 95, 912, 0, 600); ................................................................ (2)\nwhere\n* 95 = actual value when the left-side of the screen is touched [2]\n* 912 = actual value when the right-side of the screen is touched [2]\n* 0 = the left screen coordinate.\n* 600 = the right screen coordinate.", "611" ], [ "Servo Deadband Correction\nIntroduction: Servo Deadband Correction\nAnalog servos require the pulse-width to change by up to 10 microseconds before they start to move. This represents an error of almost 2 degrees. [1]\nThis instructable explains how to significantly reduce the deadband errors in the servo plotter described in https://www.instructables.com/Servo-Plotter/\nImages\n* Photo 1 shows the orginal servo plotter\n* The lower trace in photo2 shows two overlaid squares. One square is plotted clockwise (CW) ... the other is plotted counter-clockwise (CCW). Deadband is distorting the squares and causing the diagonals to separate.\n* The upper trace in photo2 shows the improvement when deadband compensation is applied.\n* The video shows servo plotter 2 in action ...", "134" ], [ "note the deadband improvement\nThe cost of the push-switches for this project is less than $5.00\nNotes\n[1]\nFor a standard servo:\n* 500uS produces 0 degrees\n* 1000uS produces 90 degrees\n* 1500uS produces 180 degrees\n* 1 degree equates to (1500-500)/180uS = 5.5uS\n* 10uS equates to 10/5.5 = 1.8 degrees\nStep 1: Reducing Mechanical Errors\nPhoto 1 shows the penlift in instructable https://www.instructables.com/Servo-Plotter/.\nThis simple penlift has a serious problem ... the servo horn tends to displace plotter arm 2 sideways when it is raised and lowered.\nRotating the SG90 servo 90 degrees doesn’t fix the problem as the servo horn is now off-center causing arm2 to twist.\nArm 2 is replaced in Photos 2, 3, 4 with a length of 3mm aluminium extrusion to which an alternate design penlift is attached.\nOnly the pen touches the paper under its own weight ... the servo arms are no longer displaced.\nNow that the mechanical errors have been minimised (there is still a tiny backlash in the gears) lets modify the circuit.\nStep 2: Circuit Diagram\nThe circuit and parts are the same as for the plotter described in https://www.instructables.com/Servo-Plotter/ with the addition of two push-switches.\nThese push-switches allow you to increase/decrease the servo pulse widths under menu control.\nThe cost of the push-switches for this project is less than $5.00\nStep 3: Installing the Software\nMethod:\n* Copy the attached file “servo_plotter_10.ino” into an Arduino sketch and save it to a folder using the same name but without the .ino extension.\n* Copy myServo.h into the folder you have just created. [1]\n* Copy myServo.cpp into the folder you have just created. [1]\n* Compile and upload “servo_plotter_10” to your Arduino.\n* Set your Arduino “Serial Monitor” to 9600 bauds.\n* The menu in photo should appear.\nCaution:\n[1]\nThe above files, myServo.h and myServo.cpp, are different from those of the same name in https://www.instructables.com/Servo-Plotter/\n15 January 2022\nAlternate software using a PCA9685 servo shield has been posted here https://www.instructables.com/ArduinoServo-Shield/\nStep 4: Calibrating the Servos\nServo Arm 1\n* Draw radials at 10 degree intervals as shown in photo 1\n* Select menu option T4 ... numbers should start scolling on your monitor.\n* Press the “decrease” button until the servo is fully left (0 degrees)\n* Now press the “increase” button and record the microseconds every 10 degrees.\n* If you overshoot press the decrease button and approach the overshot point in a CW direction.\n* You should now have 19 measurements.\n* Repeat the process, this time recording the pulsewidths every 10 degrees in a CCW direction.\n* Enter these values into spreadsheet as shown in photo 2\n* Subtract the readings at each 10 degrees interval\n* Sum these readings and divide by 19 ... this your servo deadband.\n* Record this reading as “deadband1” in the “servo_plotter_10.ino” file header.\n* Record the CCW reading for 90 degrees in the “servo1_90” header variable.", "16" ], [ "Laser Anemometer\nIntroduction: Laser Anemometer\nThis instructable explains how to make an anemometer from an Arduino Uno R3, two VL6180X laser distance modules, and a section of plastic drain pipe or similar.\nProcessing3 is used to display the wind speed and wind direction.\nThe wind direction is independent of the pipe dimensions.\nThe sensitivity to wind speed depends on the pipe dimensions and the amount of applied damping.\nConstruction is simple ... all you need is a drill , a hacksaw, and a hot-glue gun.\nThe anemometer is purely experimental and is published in the hope that the techniques will be of use to others.\nThe estimated cost to build this anemometer is between $20 and $50 depending on how many parts you have on-hand.\nImages\n* The cover photo shows the anemometer construction\n* Photo 2 shows the display\n* The video shows the anemometer in operation.\nSupplies\nThe following parts were obtained from https://www.aliexpress.com/\n* 2 only VL6180X Range Finder Optical Ranging Sensor Modules for Arduino I2C\n* 1 only Arduino UNO R3\nThe following parts were obtained locally\n* 1 only small length (150mm) 65mm inside diameter plastic downpipe [1]\n* 1 only endcap to fit the above pipe\n* 1 only length (500mm) 10mm inside diameter aluminium pipe\n* 1 only 11/16” extension spring\n* 1 only M4 bolt\n* 1 only M4 nut\n* 1 only self-tapping screw\n* 6 only lengths of hookup wire (these are threaded through the pipe)\nThe estimated cost to build this anemometer is between $20 and $50 depending on how many parts you have on-hand.\nNote\n[1]\nAn opaque plastic drink bottle with the base cut off should also work providing it is circular.\nStep 1: Theory\nThe cross-section of a pipe is a circle.\nThe points at which the two laser beams touch the inside of a pipe define the end points of a chord on this circle.\nThe length of this chord varies when the pipe is tilted (photos 1, 2, 3)\nKnowing the pipe radius it is possible to calculate the X and Y displacement of the pipe from which the wind speed and direction may be calculated (photos 3, 4)\nStep 2: Circuit Diagram\nThe anemometer circuit is shown in photo 1\nVery few parts are required ...", "16" ], [ "just the Arduino and two Vl6180X laser distance modules.\nStep 3: Construction\nStep 1\n(Photo 1)\n* Cut one loop off the end of the 11/16” extension spring (I used a diamond file)\n* Press the M4 nut inside the coiled spring\n* Solder the nut through the spring ... the solder will not take to the spring but will prevent the nut pulling out.\n* Push the other end of the spring down tube\n* Fasten the spring in place using the self tapping screw. [1]\nStep 2\n(Photo 2)\n* Cut 20mm from the bottom of an old credit card or similar.\n* Cut the length to twice the height of a VL6180X sensor\n* Lightly score the center and fold to 90 degrees\n* Hot glue this plastic angle to the aluminium tube such that it will just be covered when the plastic downpipe (or bottle) is attached\nStep 3\n(Photo 3)\n* Hot glue a VL6180X sensor to each of the plastic faces.\n* Before doing this read Step 5: Calibration below\nStep 4\n(Photo 4)\n* Drill a 5mm hole in the tube above the sensors\n* Feed three pairs of twisted wires through the hole and out of the tube.\n* One pair of wires is for VCC and GND\n* The second pair of wires is for SDA and SCL\n* Each of the remaining wires is attached to a sensor SHDN pin\nStep 5\n(Photo 5)\n* Attach the pipe and end-cap\nStep 6\n(Photo 6)\n* Mount the pipe vertically for testing [2]\nNotes\n[1]\n* The amount of exposed spring determines the damping.\n* If too much spring is exposed the tube will tend to oscillate much like a playground swing\n* If too little is exposed the tube will require a large air flow before it will tilt.\n[2]\n* A multispeed hair-dryer is useful when testing.\nStep 4: Software\nStep 1\n(Photo 1)\nDownload and install the Pololu VL6180X library.", "611" ], [ "Servo Plotter\nIntroduction: Servo Plotter\nThis instructable explains how to make an A4 plotter using three servo motors and an Arduino UNO R3.\nConstruction is simple ... all you require is a hacksaw, a sharp knife, and a 3mm drill.\nTwo plotters are described:\n* The first version, shown in photo 2, uses MG 996R metal gear servos.\n* A second lightweight version using SG90 servos is shown in photo 5\nBoth plotters use the same software which features an onboard g-code interpreter that is Inkscape compatible. [1]\nThe MG 996R plotter features a vacuum hold-down and a simple pen-lift. The reason that the sample plot in photo 6 looks weird is that servo1 is faulty ... I have some replacements on order. [2]\nWhile waiting for the replacement servos to arrive I built a lightweight plotter from two SG90 servos to verify the inverse kinematics discussed further on. The sample plot for the SG90 plotter using these equations is shown in photo 7.\nThe plotters work ...", "16" ], [ "but not as well as my digital versions.\nI am publishing my results in the hope that the construction details and solutions to issues that I have encountered are of help to others.\nThe estimated cost for the MG 996 plotter is less than $100.\nImages\n* the first video shows the SG90 plotter in operation\n* the second video shows the RDS3225 plotter in operation[3]\n* photo 1 is the cover image\n* photo 2 shows the assembled plotter\n* photo 3 shows the plotter dissassembled.\n* photo 4 shows the electronic components.\n* photo 5 shows an SG90 plotter made to the same dimensions\n* photo 6 shows a sample plot from the MG 996R plotter ... unfortunately servo1 is faulty.\n* photo 7 shows a sample plot from the SG90 plotter. The code is the same for both plotters.\nWarning : Keep clear of the servo arms when using this plotter as the motors are extremely powerful and capable of rapid movement.\nNotes\n[1]\nThe software for this plotter has been adapted from the following instructables:\n* https://www.instructables.com/CNC-Actuator-Plotte...\n* https://www.instructables.com/CNC-Drawing-Arm/\n[2]\nFor a servo plotter to work, each motor must resist the torque from the opposite motor.\nAn ideal servo should hold its position if it experiences an external torque ... in practice there is a slight movement or “dead-band” until the servo resists.\nThe dead-band for each my MG 996R servos is shown in photo 6. To obtain these curves I simply pressed against each servo arm until I felt resistance and the servo started to vibrate.\nIdeally we should only see a very small trace which is not the case for servo1\n[3]\n14 December 2020\n* The faulty MG 996 servos have been replaced with RDS 3225 servos.\n* See Step 9: Addenda ... for photos and alternate software\nStep 1: Parts List\nThe following parts were obtained from https://www.aliexpress.com/\n* 1 only Arduino UNO R3 with USB cable\n* 2 only MG996R metal gear servos (optionally RDS3225 ... see Step 9)\n* 2 only 25T (tooth) metal disc stents for MG996R servos\n* 1 only Tower Pro SG90 servo\n* 1 only Prototype PCB Expansion Board For Arduino ATMEGA328P UNO R3 Shield FR-4 Fiber PCB Breadboard 2mm 2.54mm Pitch\n* CPS-3205 II 160 w (110Vac / 220Vac) 0-32 v / 0-5A, compact digitally adjustable DC power supply\nThe following parts were obtained locally:\n* 1 only plastic dual suction_cup (photo 1)\n* 1 meter 25mm x 1mm aluminium extrusion\n* 1 only MBR735 Schottky 35V 7A diode [1]\n* 1 only 28 pin arduino header terminal strip\n* 1 only SPST switch\n* 1 only 2-way PCB mount screw terminals -5mm\n* 1 only pkt M3 nuts\n* 1 only pkt M3*10mm bolts\n* 8 only 25mm x M3 bolts\n* 2 only cable ties\nThe estimated cost for this plotter is less than $100.\n[1]\nThis diode protects your servos should you accidentally reverse your battery connections and may be omitted if you are confident that your wiring is correct.", "16" ], [ "Marblevator, Perpetual?, Cradle.\nIntroduction: Marblevator, Perpetual?, Cradle.\n\"Marblevator, Pertual?, Cradle\" like \"Marblevator, Perpetual?, Version 2\" and \"Marblevator, Perpetual?\" is not perpetual at all as it is simply another illusion. And like its predecessors it is a very quiet illusion with the only noise being that of the marble as it rolls back and forth in the cradle.\nI've incorporated an Arduino Nano 33 IoT in this model. The Nano software controls the illusion using two interrupt service routines activated by two infrared transceivers. When the ball bearing passes over an infrared transceiver, an interrupt is generated via the Nano input pin associated with the infrared transceiver, causing the interrupt service routine associated with the pin to be called. Each interrupt service routine utilizes the interrupt history of both interrupt service routines in order to detect downhill ball bearing motion. When downhill motion is detected, the software pulses an electromagnetic coil in order to accelerate the ball bearing up the other side of the track (as the model uses infrared transceivers to sense the ball bearing, it cannot be operated where an external source of infrared is present as that will flood the infrared transceivers thus render the model inoperative).\nI've also included software that monitors the battery voltage via a resistor divider and analog input pin to put the Nano to sleep when the LiPo battery voltage drops below a specified cutoff level (9.6vdc).\nAs usual, I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to ask as I do make plenty of mistakes.\nDesigned using Autodesk Fusion 360, sliced using Ultimaker Cura 4.12.1, and 3D printed in PLA on Ultimaker S5s.\nOne final note, I receive no compensation in any form for the design, parts and/or materials used in this model.\nSupplies\n* Soldering iron and solder.\n* One roll each of red, black, green and blue 28AWG stranded wire.\n* Micromesh polishing sheets (1200, 1500, 2400, 3200).\n* Sandpaper (120, 220, 400 and 600 grit).\n* Thick cyanoacrylate glue.\n* Double sided tape.\n* Velcro.\n* Heat shrink tubing.\nStep 1: Parts.\nI acquired the following parts:\n* One Arduino Nano 33 IoT [ABX00027]\n* One 11.1vdc 300mAh 3S 30C battery LiPo battery.\n* One JST mating connector for the battery.\n* One Gikfun EK1909 \"magnetic levitation coil\".\n* Two TCRT5000 infrared transceivers.\n* One FQP30N06L MOSFET.\n* One 1N4007 diode.\n* One 10kΩ resistor.\n* One 2.7kΩ resistor.\n* Two 1KΩ resistors.\n* One M3 by 8mm cap screw.\n* One 11MM diameter ball bearing.\n* One M3 by 8mm cap screw.\nI 3D printed the following parts at .1mm layer height, 20% infill:\n* One \"Base.stl\" with PLA support.\n* Two \"Bolt, Mount, Coil.stl\".\n* One \"Bottom.stl\".\n* One \"Mount, Coil.stl\".\n* One \"Track.stl\" with breakaway or PVA support (requires a dual extrusion 3D printer, see Cura image above).\nThis is a precision print and assembly model using at times very small parts and in very tight spaces.", "654" ], [ "Prior to assembly, test fit and trim, file, sand, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on you printer, your printer settings and the colors you chose, more or less trimming, filing and/or sanding may be required. Carefully file all edges that contacted the build plate to make absolutely certain that all build plate \"ooze\" is removed and that all edges are smooth. I used small jewelers files and plenty of patience to perform this step. After 3D printing \"Base.stl\" and \"Track.stl\" I carefully removed the support material using a flat jewelers screwdriver and needle nose pliers.\nThe model also uses threaded assembly thus an M8 by 1.25 tap and die will assist with thread cleaning if necessary.\nStep 2: Board and Coil Mount Assembly.", "632" ], [ "P-CNC Laser Engraver and Pen Plotter\nIntroduction: P-CNC Laser Engraver and Pen Plotter\nIn this project, I'd like to share how to build a homemade 3 axis P-CNC machine with its frame and supports made of PVC pipes and acrylic sheets. It has two operation modes: pen plotting and laser engraving.\nPlease check the brief description and how P-CNC Engraver & Plotter works in the video below before getting started in detail.\nStep 1: Supplies\n1. Main materials:\n* 1pcs x 3 Axis Control Board GRBL With Laser Engraver Supported.\n* 1pcs x 2500mW Laser Module.\n* 3pcs x Stepper Motor Driver A4988.\n* 3pcs x Stepper motor NEMA 17.\n* 2pcs x GT2 6mm Closed Timing Belt 200mm.\n* 2pcs x GT2 Timing Pulley 20 Teeth.\n* 2pcs x GT2 Timing Pulley 60 Teeth.\n* 3pcs x Round Shaft Diameter 8mm, Length 400mm.\n* 3pcs x T8 Lead Screw 2mm Pitch, 8mm Lead , Length 400mm with Copper Nut.\n* 20pcs x Ball Flanged Shielded Bearings 8 x 22 x 7mm.\n* 1pcs x Aluminum Flexible Shaft Coupling, Inner Hole Size: 5mm x 8mm.\n* 1pcs x Aluminum Flexible Shaft Coupling, Inner Hole Size: 10mm x 10mm.\n* 1pcs x Power Supply 12VDC.\n* 2pcs x Clear/White Acrylic, size A4, thickness at least 5mm.\n* 4pcs x Copper Brass Pillars L-5/10mm.\n* 1 meter x 8P/16P Rainbow Ribbon Cable.\n* Some small cable ties, cable spiral wrap, M3/M4 bolts and nuts, some small neodymium magnets.\n2.", "1000" ], [ "PVC pipes and its fittings (with some spares):\n* 8pcs x PVC Pipe Elbow Ø42mm.\n* 8pcs x PVC Pipe Straight Connector Ø42mm.\n* 14pcs x PVC Pipe Tee Ø42mm.\n* 3pcs x PVC Pipe Cross Ø42mm.\n* 16pcs x PVC Pipe End Cap Ø42mm.\n* 6pcs x PVC Pipe End Cap Ø60mm.\n* 3pcs x PVC Reducer Ø60mm to Ø42mm.\n* 2pcs x PVC Reducer Ø50mm to Ø42mm.\n* 2 meter x PVC Pipe Ø42mm and Ø60mm.\n3. Tools:\n* Drilling machine with drill bit hole 8/22mm.\n* Hand saw.\n* Hand grinder.\n* Soldering machine.\n* Big scissor.\nStep 2: Connection\nI used a GRBL-based controller for a 3-axis CNC machine and it supports laser control.Connection diagrams:\n* Plugging three stepper motor drivers A4988 on the CNC controller at X, Y and Z label position.\n* Connecting the cables from CNC controller to three stepper motors.\n* The laser module has 3 wires connected to a female header: Red (12V+), Black (GND), Yellow (PWM) and I just connected it to a 3-pin laser male header on the CNC controller with the same label.My laser module parameters are shown on the nameplate as follows:\n* Wavelength: 450nm.\n* Power output: 2.5W.\nThe NEXTPCB support me for this project. If you have a PCB project, please visit the NEXTPCB website to get exciting discounts and coupons.\n* Only $0 for 1-4 layer PCB Prototype: https://www.nextpcb.com/pcb-quote?act=2&code=tune...\n* New customer get $100 coupons, register at: https://www.nextpcb.com/register?code=tunendd\nHere are mid-summer sales at NextPCB:\n* Up to 30% off for the PCB orders.\n* Up to 20% off for the PCBA orders.\nStep 3: Building P-CNC Frame\nI assembled a PVC frame, with horizontal dimension L480 x W480mm and vertical dimension W480 x H550mm.\nIt was made of:\n* 10pcs x PVC tees Ø42mm.\n* 6pcs x PVC elbows Ø42mm.\n* 8pcs x PVC straight connectors Ø42mm.", "1000" ] ]

[ 9782, 1756, 1844, 5543, 4550, 6699, 4814, 3568, 4760, 8686, 2175, 8009, 3614, 5688, 5814, 2536, 1341, 9277, 8252, 7980, 9647, 10589, 6168, 4307, 7961, 7255, 4734, 2917, 5067, 4092, 277, 5757, 1437, 4391, 3507, 6609, 6612, 5907, 3490, 8899, 2732, 1364, 3803, 545, 1773, 2033, 5667, 11138, 552, 3144, 5454, 7797, 11276, 11175, 3633, 4189, 3574, 6988, 5366, 6065, 5281, 8267, 2822, 3811, 10147, 11273, 6896, 5441, 3207, 11256 ]

[ [ "<PERSON> comes to mind as an example of a human experiencing similar conditions to your creatures. I seem to recall that before being taught sign language, she could still make herself somewhat understood, though that may be because her family could see/hear. So I'm going to throw out this example for the rest of this answer.\nInstead, I want to imagine how these creatures would live. For one thing, if they're loners, they're not going to develop language no matter how easy it is, so let's assume they're pack animals. Thus, they will sleep, move, and eat together, and feel terror when they are alone. For these reasons, I imagine that much of these creatures' time will be spent in physical contact with one another (think of people walking in a snowstorm, or WWI soldiers blinded by poison gas in long lines, holding onto each other for direction). It may be possible that a group will never let go of one another, forming lifelong partnerships with the individuals in front of and behind them. They're going to end up knowing a lot about these two people, and should be able to tell their mood just by feeling their body language-- that is, if they have body language at all.\nI think rather than a static line, it's more likely that individuals will remain connected, but often switch their place in the group.", "802" ], [ "That way, the alpha can make sure no one is plotting against them, and no one has been left behind. Also, it allows the young to learn from a variety of sources. This way, I think body language will develop, as there are certain things individuals will want to tell each other (for instance, \"I don't want to hold your hand\", or \"don't leave, you're not as sweaty as the other guy\"). This may come in the form of hand signals (like soldiers entering a building tapping each other's shoulders), or more subtle cues like posture. Keep in mind that without most senses, these creatures' sense of touch should be much more precise than ours, so they should be able to pick up a variety of cues that we couldn't, such as small changes in heartbeat or hairs standing on end.\nWhether or not this all turns into a form of communication that we would call language is debatable, and mostly based on the potential these creatures have for intelligence. However, with the example of <PERSON> again (I know, I said I wouldn't bring her back up, but she didn't hear me when I told her to leave), she learned to understand sign language by feeling it, so sign language could be used by these creatures to communicate as long as they were smart enough to develop it.\nAs for written language like braille, I think it should develop eventually, just like written languages did for humans. Come to think of it, it may develop earlier: these creatures should already be used to combing the ground for familiar paths and handholds, it shouldn't be too much of a leap to place certain objects with special meaning in places where they will be found. This may start as a way to more easily find places, but could evolve, again based on the intelligence of these creatures.", "802" ], [ "How long would it take for another species to help primitive humans evolve?\nI am creating a fictional universe where humanity's evolution followed a different path that it did in ours (evolution might not be the best word, but bear with me).\nLong ago, in said universe's equivalent of what we call the prehistory (i.e. when the first humans started appearing), there was already another intelligent species roaming the planet. This species, who, at the time, had already advanced to a similar point where modern-day humans are (speech, culture, industry, technology, you name it) and decided (for reasons that are beyond the scope of this question) to help the humans (who were little more advanced than cavemen) to develop speech, culture and the rest.\nThe question here being: how long would it reasonably take before humanity would be able to get from prehistoric level to, say, the Industrial Revolution under this species' guidance? Decades? Centuries? Millennia?\nAdditional info:\n* You may assume that the planet is Earth when it comes to measuring time; 365 days of 24 hours (in layman's terms).\n* There is no need to take into account the state of planet Earth in our prehistory; you may assume that the state of the planet at that time was roughly similar to present-day Earth.\n* Humans had not encountered this species before, despite living on the same planet. However, humanity was generally not afraid of this species, but would accept their teachings from the first meeting.\n* Humans in this universe are otherwise pretty much completely identical to real-world humans; there's good ones and bad ones, smart ones and not-so-smart ones, people that would gladly accept the teachings and those that would not, etc.\n* Said species had different vocal chords than humans and could thus not teach humans their own language exactly like they spoke it; it would be either an approximation of their own language or an entirely new language designed specifically for human vocal chords.", "350" ], [ "At this point, I'm inclined more towards the latter, especially because of the next point.\n* Another difference between humans and this species meant that their writing system was difficult for humans to read and write fluently, too. They could read/write it when taught, but it would take them longer to read it compared to a writing system aimed at humans and even longer to write, even after they become fluent.\nEdit: there seem to some misconceptions going on about the level of humans before this meeting. When I say they had 'no language', I mean they had no structured language with grammatical rules; they could speak among themselves by using sounds such as grunts and such and by using body language. They had some basic tools and could probably create fire already. But they had nothing in the way of culture or civilization.", "802" ], [ "It might go something like this: people begin exploring this new region and notice that they never get very close to the animals that live there. They seem to sense them even when they are walking very stealthily (as they would surely know how to do). They may suspect that these animals have much better hearing than humans do, so they'd probably try to stand completely still to avoid making any noise.\nThey may notice that this works a lot better in forested areas than in plains, but no one can figure out why. Some of them may get tired standing in the plains all day waiting for animals, so they often lie down in the tall grass while they wait. It's soon noticed that the animals get much closer before they're able to detect the humans and run away. These and similar observations are recorded and brought to their best natural philosophers with the hope that they will be able to make some sense of them.\nThese people, although sightless, would certainly have a good understanding of 3d space, since they must navigate it somehow to find food, materials for tools and shelter, to avoid predators, etc.\nMost of the people already realize that the way these animals are detecting their presence depends heavily on the geometry of the surrounding environment and their position in the environment relative to other objects. It wouldn't be too big of a leap to notice that when there are objects (grass, trees, boulders, etc.) between the (silent) humans and the sighted animals, they usually cannot be detected by whatever sense the animals are using. This wouldn't seem too far-fetched because the presence of obstacles affects their own ability to hear sounds emitted from the other side of those obstacles (usually making them more difficult to hear).\nThey notice that the sense used by these animals is affected to a much greater degree by the presence of objects between them and the animal than their own sense of hearing is affected by the same obstacles. From there it's a pretty straightforward idea to surround oneself with objects while waiting for the animals.", "802" ], [ "When this technique is used, the animals get closer than ever before and the humans often go completely unnoticed.\nAt this point, even though they don't understand the exact nature of sight, they now would have the ability to counteract the animals' sense of vision. Now, I'm not sure what you mean when you say that traps are not allowed. I don't know why the fact that these people don't trap animals for food would mean that they couldn't come up with the idea to set a trap. I'm also not sure what you would consider a trap. Is it just that automated traps aren't allowed or can they lie in wait and pull a rope to trigger the trap at the right moment? If neither is allowed, how else would they capture an animal? A lasso? Running up and grabbing the animal? Both of these would be extremely difficult (and most likely quite dangerous) for blind people.\nIf a manually triggered trap is allowed, then all they would have to do is get some bait, hide themselves and wait for an animal to come, use the sounds made by the animal to determine it's position and trigger the trap at the right moment. It may take a few tries, but they would get it right eventually. If this kind of trap isn't allowed, I guess do the same thing except instead of triggering a trap, just get a bunch of people to run toward the animal from different directions and hope it's not a bear or a deer. Although this is more of a stone-age level of sophistication than a Renaissance one.\nEdit: I wrote and posted this before I saw the extensive changes you made to the question, including the removal of the restriction on traps. Does that mean they're allowed now? If so, I'll change that part of my answer.", "376" ], [ "To balance out the long lifespans, you would essentially need your animals to have long hibernation periods. You could build a world where as the animal grows, the need for food decreases or that the need to feed regularly disappears. Now since the environment is already saturated with magic, I expect the animals to absorb some of it. If they absorb enough, the magic can help regenerate dead cells at a much faster rate. If this continues for long enough, perhaps the animal becomes essentially invincible (e.g., the moment a sword piercing this snake is removed, it heals from the wound). For particularly old animals (30,000 years) you could replace their biological need to eat with absorption of magic in the environment.\nAnother thing that you can do is stop the physical growth. In normal world, animals grow up to a certain size till a certain age and stop growing so much once they reach adulthood.", "227" ], [ "It could be the same there. You could remove the reproductive system after a certain age, even replace hearts with pure magical cores.\nThe skill an animal is learning would also probably depend on their upbringing and inherent abilities. For example, a lame lion would learn speed or stealth while a lion who has generally starved throughout childhood would learn to be a better tracker. For smaller animals you could try increasing their size just enough that its natural predators would be afraid of it.\nLastly, you could make the animals less violent than their normal counterparts. They will generally not pick fights with smaller animals if there is no need. I believe an animal smart enough to learn magic will be smart enough to maintain truce with other animals like itself, i.e., with magical abilities because it will simply not take the meaningless risk just for thrill or food, if it doesn't need it. If you do, however want to make your animals violent, I suggest a specific reason. For instance, if animal A defeats animal B in combat and kills it, A will gain the magical abilities originally belonging to B.", "376" ], [ "How would an isolated world grow its population, then keep it stable?\nThe scenario\nIn the scenario that I'm imagining, a small group of people (ideally 100 or less) travel to a parallel universe and begin a new society. The new planet that they land on has one land mass surrounded by water, with sufficient freshwater resources and enough fertile land to build a prosperous agriculturally-based society. There are no existing cultures on this planet, and they have no further way to interact with any other societies. In other words, no one can immigrate to them, and they can't emigrate to other places.\nThe question\nThe population needs to reach the continent's capacity (we'll say that's about 5-10 million), then remain stable. What kind of laws or societal norms would have to be enforced to ensure this quick rise and then leveling out of the population? How would this affect their society? For example, is it plausible that a society could be so focused on increasing the population, then do a quick 180 turn and change their rules/norms/familial institutions to focus on population stability?\nAssumptions about the society\nMy initial thought was that, once they reach their population capacity, the familial structures would put less focus on having children biologically, and more focus on contributing to a child's upbringing as a teacher, or by mentoring them, for example.", "183" ], [ "I also imagined that the society wouldn't be heteronormative because having children isn't a priority, and that the people who do have kids wouldn't be encouraged to have more than one.\nHowever, after doing some reading on here about other isolated/stable populations (such as here: https://worldbuilding.stackexchange.com/questions/100924/maintaining-a-constant-population-in-a-country), I've learned that these assumptions might be wrong. For example, in order to continue replacing the population, if not everyone is having kids, you might need an average of 4 kids per woman who does choose to reproduce.\nMore info about the world I'm trying to build\nTo get to this world, the pioneers travel using magic that is nearly impossible to wield. So, they can't really use it to build their new society. Also, since they don't want their descendants to find a way back to the world they escaped from, they don't pass on the knowledge of the magic's existence.\nThe world that they come from has a medieval or renaissance level of technology.\nThe new world is 'egalitarian' in nature, or at least, its inhabitants buy into the illusion that it is. The society doesn't experience wars and has very little crime (that the general population knows about, anyway), but there is some corruption bubbling under the surface, that will come to fruition in the story's plot. In terms of how the world is set up, though, it needs to appear as though everything is peaceful and carefully planned.", "693" ], [ "First off, this is a very cool concept! Your question is fairly broad, so I was going to answer a few different ways.\nSociety - just like how oceans and mountains separate societies and cultures in our world, the separate floating continents would likely give rise to different cultures. This would extend to their belief systems (do they all know/believe the gods raised the continents or do they each develop different beliefs about how/why floating lands exist? What legends have they come up with about the Earth's core?) and their technology (presumably, some societies would invent aerial vehicles to travel around while others might exploit natural resources - such as huge flying birds).\nBiology - depending on how high up these continents are, your world's inhabitants would have adapted to slightly less gravity (though the difference is probably negligible) AND less oxygen. To be more precise, the concentration of oxygen is the same whether you are standing at sea level or on Mt. Everest (21%) but there is less atmospheric pressure, so it is harder to breathe.", "279" ], [ "If your societies are human, their bodies would have adapted by breathing faster and producing more hemoglobin. Because of this, if the humans were to descend to the Earth's \"surface\", their stamina would likely increase since they are now presented with \"more\" oxygen for their bodies to use.\nEconomy - I imagine mining would be a great deal easier with so much of the underground earth exposed, so you might want to think of how a society would look with an abundance of precious metals. Would their currency be based on something entirely different from gold and silver?\nWater - though it would still be replenished through rain, having rivers that flow off the continents would pretty quickly lead to a water shortage. So either water is very precious and/or they have much more advanced ways of saving water.\nLand - earthquakes wouldn't exist, right? Is there a concern the continents might run into each other from time to time? Do they have technology to deal with this?\nIt seems to me that there is a lot you could do with this concept. Good luck!", "693" ], [ "All right, so let's say you have this spacefaring race. They've been expanding, getting themselves into new environments, and having babies on completely new planets. The only problem is that some of these babies don't develop too well in these new environments; some are stillborn, some deformed, and some are just straight up missing things. One of these things is the Parthen version of a uterus.\nFor the latter deformed babies, the future looks pretty grim; without the possibility of bearing children, they'll look to other ways of attaining lasting happiness and satisfaction. Some may become doctors and biologists, and in their hi-tech world, they may seek answers as to how to solve their infertility.\nFinally, after decades of research, a solution is devised: they can't repair the uterus, and it's too late to clone and insert a new one, but what they can do is hijack the uterus of a surrogate mother, splicing DNA from both parties to create a hybrid baby.", "1008" ], [ "And since the baby is getting genetic material from both mothers, it's got a fifty-fifty chance of having the same deformity, and needing to use the same process to have its own children.\nI think you said somewhere that some of your Parthans already couldn't reproduce on their own; this solution could work for them too.\nWhat I'm imagining is some sort of cyborg-genitals (never thought I'd say that), but given an advanced enough species I guess it's possible that they could just use some other parts of Parthan anatomy to get the job done. Perhaps the baby would get all of the 'father' DNA, instead of a split; that would make more sense to me, but may not work in your story. Also, with more of a biological solution, there could be more drastic physical changes due to hormones, leading to a more 'masculine' appearance (rather than a woman with a baby-making attachment strapped on).\nAfter a while, this solution might not be the best one (that is, the original problem may have been solved in a more satisfactory fashion), but by then there would be enough 'men' around to sustain a viable population. Plus, by then the Parthans might have found more uses for them, such as the ones other answerers have mentioned.\nWhat I'd like to stress with this answer is that it sounds quick and dirty, but that's exactly why it makes sense: people will go to great lengths to ensure the survival of their genes. The solution may not be the best, but given the direness of the problem, some concessions can be made.", "1008" ], [ "From a philosophical perspective, punishment for crimes is mainly used as a deterrent to further crimes. You don't cut off a thief's hands because they've been a bad boy, you do it so they don't steal again and so other people will be too afraid to steal at all. Now, whether such punishment actually lowers crime rates is debatable (not the hand-cutting part, I hear that works wonders, but things like prison), but I would say if we lived in a world where we knew who was going to do what, and when, punishment would be replaced by prevention.\nLet's keep going with the hand-cutting analogy. Say someone is going to steal; instead of cutting his hands off after the fact, just put him in handcuffs before he does anything. Since you know what crimes are going to happen in the future, you just detain him until you know he's not going to steal any more, or until he appeals for release (because of 'minority reports', you're going to want to give the wrongfully accused a chance to go free). For more heinous crimes, you might have to keep the suspect detained for longer periods of time before their futures become bright enough to set them free (now this is beginning to remind me of the anime Psycho-pass). Perhaps the government can provide counseling for these suspects (remember, you're innocent until proven guilty, and you can't prove someone guilty when they haven't committed the crime), in the hopes that they will think better of their criminal plans faster.\nI'd think that many of these cases will look like imprisonment, but won't feel like imprisonment. If the government knows about and can stop all crimes, no one will ever have the chance to become a hardened criminal; they'll simply get arrested at a young age, then released once they've learned the error of their ways. The only problem you run into is when people need to commit crimes, such as poor people who need to steal in order to survive.", "238" ], [ "In these cases, though, if the people are in jail, getting food and shelter, and not surrounded by terrifying people, then maybe it'll actually be a pretty good solution to poverty.\nThe main problem I see with this is the public's reaction. If you can get this system up and running, people may end up being fine with it (oh, you think I'm too stressed out and about to kill my boss? You're going to take me away from my job for a few weeks, so I can rest up and reevaluate my life? Sounds great!), but the biggest problem is getting it started. There will be a lot of cases that appear to not make sense, where innocent people are incarcerated for seemingly no reason. Plus, there will still be really bad guys in the prisons, so it's possible what started as a preventative measure will turn decent people into even worse criminals. And since you know what people are going to do, someone you put in jail for thinking about stealing might end up staying in jail their entire life, as each day they think of a new way to kill you for holding them so long.\nThere's also the problem of giving the government so much power. If the technology behind it is sound and the people using it are very transparent about their methods, it might be okay, but people generally don't like it when the government knows things about them. Maybe if there is another large terrorist threat, people might give up some freedom in exchange for safety, but due to the problems I've already mentioned I don't think they would get used to the changes before deciding to abolish them.\nSo, long story short, the end result sounds pretty good to me, but I don't think it could ever get started without pretty much everyone opposing it.\nEDIT: I would also like to point out the case of car insurance. People my age (early 20s) don't think it's fair that they get charged more just because they're more statistically likely to get into accidents. Insurance is a really great example of pre-crime-punishment in modern society, as people have to pay for things they may never actually do. And I think people's reaction to insurance is a pretty good indicator that this kind of crime prevention system wouldn't really work.", "852" ] ]

[ 977, 10081, 9541, 606, 2079, 7609, 3304, 10768, 7963, 9554, 5235, 1882, 8475, 8864, 5475, 4980, 1818, 5839, 7562, 4276, 2143, 8256, 4685, 8479, 6914, 5703, 1948, 3968, 5, 9744, 10616, 5236, 10986, 5573, 2014, 11102, 6550, 8429, 10826, 4642, 1944, 6247, 38, 5360, 2760, 6577, 1877, 2392, 9998, 4427, 3669, 4615, 9488, 291, 2906, 9890, 10999, 452, 1179, 142, 7921, 11156, 3115, 7232, 2579, 7739, 2495, 6517, 10487, 4 ]

[ [ "The Dress Rehearsal for the Belarusian Crackdown · Global Voices\nTotal media control, or the unexpected virtue of being <PERSON>. Images edited by <PERSON>.\nThe state of free speech in Belarus enjoys remarkable stability: in 2015, Belarus placed 157th out of 180 countries on Reporters Without Borders’ Press Freedom Index for the third consecutive year. Attacks on the independent media have been commonplace since the 1990s. Restrictive laws, raids on newspapers, politicized criminal prosecutions, travel bans against outspoken reporters, and failing to investigate the murder of several journalists—Minsk has used every possible tool in its arsenal against the free press.\nThe Belarusian president, <PERSON>, who's sometimes called “Europe's last dictator,” once said journalists “hold a weapon of a most destructive power.” That's the reason, he says, the state must exercise such control over the media.\nToday, Minsk controls the media almost entirely. There are a few rare exceptions online, like the opposition news outlets Charter 97, Naviny.by, Belaruspartisan.org, the newspaper Narodnaya Volya, and a few others. <PERSON> would probably be happy to shut down these publications, too, but they provide a semblance of pluralist democracy that's useful when responding to criticisms at home and especially abroad.\n<PERSON> headed a collective farm before the Soviet Union collapsed. Today, he treats the Internet with a mix of awe and caution, regarding it as one of mankind's greatest creations, albeit a potentially dangerous, inherently American weapon.\n<PERSON> and his youngest son <PERSON> during harvesting on the territory of the presidential residence. Image: Press-service of the president of the Republic of Belarus.\nBelarus’ suppression of the media becomes especially violent during election season. During the last election, in December 2010, several opposition websites and some entire social networks went down, targeted by blocking and hacking efforts. Police raided the offices of Belsat TV and European Radio‘s local station, detaining several journalists.", "704" ], [ "<PERSON> declared victory in the election, but an international monitoring group from the Organization for Security and Cooperation in Europe said the election was neither free nor fair. Between 10,000 and 60,000 people gathered in downtown Minsk to protest the voting results, but police special forces dispersed the crowd by force and arrested as many as 700 protesters, as well as seven of the nine presidential candidates.\nThe next election will take place later this year, in November 2015, and the country's political situation promises to be even more volatile. Five years ago, most Belarusians lived in relative comfort, enjoying rising wages and retirement benefits. In 2011, however, the country's currency reserves ran out, and the dollar exchange rate nearly tripled from 3,100 Belarusian rubles in March 2011 to 8,700 by October. (Today, it takes almost 15,000 Belarusian rubles to buy a single US dollar.) The value of oil worldwide, too, has plummeted. <PERSON> has managed to contain the economic crisis thanks mainly to generous loans from Moscow.\nIn 2015, the Belarusian government owes its creditors roughly $4 billion, which is about two-thirds of its entire foreign reserves. The Belarusian economy, dominated by large, inefficient state-owned companies, is little reformed from its Soviet predecessor. The longer the country's financial woes continue, the less likely it is that Russian aid can rescue <PERSON> from a reckoning with voters. Also, Russia's own imploding economy, not to mention <PERSON>'s refusal to endorse the annexation of Crimea, jeopardizes this one remaining lifeline.\nOfficials in Minsk seem to realize that a cataclysm might be ahead, and there are signs that Minsk is moving to address the situation, ahead of presidential elections. Last December, the parliament adopted amendments to regulations on the media, equating the online media with the traditional mainstream media. The reforms also grant the Ministry of Communications and Informatization the power to shut down online resources extrajudicially.\n<PERSON>, founder of the independent website By24.", "704" ], [ "Belarus Catches Up to Russia With Its Own Pro-government ‘Troll Factory’ · Global Voices\nBelarusians are noticing suspiciously similar comments under news articles—are government trolls to blame? Images mixed by <PERSON>.\nAs the relations between Russia and the West soured over the ongoing crisis in Ukraine, Kremlin officials have been intensifying their information manipulation efforts. This summer for the first time the world found out about Russian troll factories—the secretive agencies that hire people to write and spread pro-Kremlin propaganda on the Internet.\nIt turns out, there is a online troll factory in Belarus as well. Several months ago local media detected accounts posting similar positive comments about the Belarusian ruble to US dollar exchange rate. The dollar exchange rate has soared almost six-fold during the last five years, with the Belarusian ruble heavily dependent on the state of neighboring Russia's economy, which is currently in deep trouble. At the end of August, 2015, the US dollar surpassed 17,000 Belarusian rubles—a record high. For reference, at the beginning of 2011 one US dollar cost 3,000 Belarusian rubles.\nIt was in August of this year that journalists of the opposition newspaper Nasha Niva (Our field) first noticed that some users were praising the ruble, at the time when it was so unstable. The suspected trolls would write that they “believed in ruble” and that Belarusians would overcome all temporary difficulties: “Don’t panic! Everything's gonna be alright!” Journalists dutifully copied all the “suspicious” comments and published a collection of them on their website (many original comments have since been deleted after the “unmasking.”)\nIn general, the Belarusian trolls are seen using three main tactics.", "564" ], [ "First, one should say that everything is alright and that any concerns about the issue are simply a sign of panic.\nРешили посеять панику? Зря. Валюты в обменниках хватает. Покупайте! И вообще-то, в стране все под контролем)))\nSo you decided to spread panic? It's no use. There is enough currency in exchange offices. Buy it! And, by the way, everything in the country is under control.\nSecond, one should mention that Belarusians don't need dollars, because they spend their money in Belarus, not in the US.\nНавошта мне гэтая амерыканская валюта!? Я усе свае дабро берагу у беларуских рублях. Я жыву у Беларуси, а не у Амерыцы\nWhat do I need this American currency for? I keep all my savings in Belarusian rubles. I live in Belarus, not in America.\nAnd thirdly, always blame the West.\nВсе мы понимаем, почему происходит падения рубля: сейчас это явно спровоцировано из вне. И если бы власть сегодня «показушно» сдерживала курс, то неизвестно к чему бы это привело к концу года.", "564" ], [ "In the heat of political crisis, Belarus launches first nuclear power plant · Global Voices\nAstravets nuclear power plant, Belarus, 2020. Photo (c): <PERSON>, used with permission.\nSince August, Belarus has been rocked by mass protests and strikes. The authorities try not to pay attention, for they are preoccupied with a no less historic development — the construction of a new nuclear power plant. That is controversial in a country which suffered greatly from the 1986 Chernobyl catastrophe in neighbouring Ukraine. Concern at the state of democracy dominates Belarusian public life, but alongside it another urgent conversation continues — about the country’s past experience with nuclear power, and whether it needs a post-nuclear future.\nAll eyes are on Astravets, a small town located near the Belarusian border with Lithuania. In recent years the town’s population has grown significantly: workers are badly needed, and new multi-storey apartments have shot up to house them.\nThe reason for these rapid changes is that Belarus’ first nuclear power plant is located outside the town. Its construction is now coming to an end and it is nearly ready to be started up. As engineers often explain, it takes more than pressing one button to launch a nuclear reactor.\nThat start-up will take place in several phases. The fuel has already been loaded; the plant is expected to generate its first electricity on November 7. This is a national holiday in Belarus, as it is the anniversary of the October Revolution — the revolution from which the Soviet Union was born.\n“I invite everybody. I think that on November 7, a significant day for us, we will be able to visit and say that we have received the first electricity from our own nuclear power plant”, exclaimed Belarus’ longtime ruler <PERSON> at a meeting with officials on September 16. The first of the two reactors is expected to operate at full capacity by the first quarter of 2021. The second reactor will be launched in 2022.\nHaunting memories\nBut not all Belarusians are so jubilant.", "739" ], [ "They remember the explosion in 1986, which released large amounts of radiation into the atmosphere. Belarus suffered more than anywhere else in the Soviet Union; a third of all the radioactive caesium-137 ended up in Belarusian territory. The authorities in Minsk have tried to assuage fears of a second Chernobyl, declaring that the likelihood of accidents is minimal, and that the Astravets nuclear power plant is a safe and profitable project.\n“We are the Chernobyl republic, we have experienced a lot and we know the consequences ourselves. Some US$19 billion has been spent on rehabilitating contaminated areas alone. Therefore, safety measures during the construction of the [Astravets] power station were like something out of wartime”, said <PERSON> in August, just before the presidential elections.\nIn the public discussion about nuclear energy, comparisons between Chernobyl and Astravets are not so uncommon. These parallels are drawn by everybody, including journalists, politicians, ordinary citizens, and surviving liquidators from the Chernobyl catastrophe. They all deeply regret what occurred in 1986, but their opinions on 2020 strongly differ. Some strongly support the new nuclear power plant and hope for an increased standard of living, while others fear another accident.\nBelarusian state media and officials do not shirk from mentioning Chernobyl, either.\n“The memory of the events at Chernobyl is now being instrumentalised and used to legitimise the new nuclear power plant. On the 30th anniversary of the accident, a documentary film was broadcast which began with footage of the 1986 accident and ended with a hint that this time, everything would be alright,” writes <PERSON>, head of public history projects at the European College of Liberal Arts in the Belarusian capital of Minsk.\nOnce the nuclear power plant is fully operational, explained the authorities in the early stages of construction, electricity prices will fall. In 2014, the Ministry of Energy promised that electricity “will become cheaper for the consumer” by 20-30 percent.\nBut some Belarusians seem to be sceptical about promises of cheap energy. They also doubt that the power plant will open at all, given that its launch has already been postponed at least four times. All these views can be seen in local community groups on social media:\n“I work on the construction site of the nuclear power plant, and [acquaintances] sometimes ask me when it will be launched. I think [the plant’s management] don’t even know themselves, they say within two to three years at a minimum”, says <PERSON>, who was born and grew up in Astravets, in a Telegram chat with GlobalVoices.\nDoes <PERSON> expect a drop in electricity prices?", "704" ], [ "How global tech companies enable the Belarusian regime — and the Belarusian revolution · Global Voices\nProtest rally against <PERSON> in Minsk, capital of Belarus. Photo CC BY-SA 3.0: Homoatrox / Wikimedia Commons. Some rights reserved.\nBelarusians continue to protest against longtime ruler <PERSON>, braving police violence and the cold. As the EU prepares its third package of sanctions against Belarusian officials and enterprises, demands are growing for the West to apply greater economic pressure, in particular to consider banning the supply of certain IT products.\nCould such sanctions really work? It’s true that disentangling the country’s supply chains from the West would be no easy feat. But in today’s globalised world, there’s no shortage of alternative options.\nA banking ban\nOne of the most prominent struggles is disconnecting Belarus from SWIFT, the global banking communications network.\nThis month, Golos (“Voice”), an online platform started by the team of jailed presidential hopeful <PERSON>, polled Belarusians on whether they would support excluding Belarus from SWIFT. Out of more than 400,000 respondents, 64 percent supported the measure.\nSWIFT may not be an official EU institution, but as a Belgium-based cooperative it has to follow EU rules and regulations. Should it be instructed to disconnect Belarus, as it did to Iran in 2012, SWIFT will effectively be supporting the Belarusian opposition’s demand for greater economic pressure on <PERSON>’s regime.\n<PERSON> himself has acknowledged that threats to disconnect Belarus from SWIFT have been successful at least once. In his interview for the Ukrainian website GordonUA just three days before the August 9 election, the Belarusian leader recounted his 2009 meeting with the EU’s High Representative for Foreign Policy <PERSON>. “I asked him what would happen if we recognised the sovereignty [of Abkhazia and South Ossetia]… He was prepared for that question.", "534" ], [ "He took out a notebook and started listing: ‘Mr President, Belarus would immediately get disconnected from SWIFT transactions. That was the most serious of the sanctions,” recalled <PERSON>. The Belarusian leader went on to claim that as Russia had not provided any assurances to compensate Belarus for such losses, two breakaway territories in Georgia were never officially recognised by Minsk.\nThe idea has once again gained traction during recent protests. On November 10, <PERSON>, director of the dissident Belarus Free Theatre, stated that the West should disconnect Belarus from SWIFT as a response to the authorities’ decision to freeze funds to victims of repressions which had been collected through the #BY_help crowdfunding campaign.\n“Today <PERSON>’s power is based on the greed of the security forces, the cowardice of state officials and the indecisiveness of part of the population… Any significant pressure from the international community is perceived by the pyramid of power as a weakness for the dictatorship’s foundations”, explained <PERSON> in an interview with GlobalVoices. “These measures deprive the dictatorship of the resources to pay wages to security forces and state officials”.\nMany in the Belarusian opposition appear to share these hopes. In November, opposition presidential candidate <PERSON> repeated these calls.\n<PERSON> was outraged, claiming that those who called for Belarus to be disconnected from SWIFT wanted to “destroy the country”.\nBut then the pro-government line changed, attempting to downplay the significance of such a move.\nAccording to the Nasha Niva newspaper, in late November the National Bank of Belarus sent a letter to private banks asking them to connect to the Russian-run Service Bureau SPFS system as soon as possible. This means that even if the EU and US can persuade SWIFT to disconnect Belarus, all major payments will be routed through Russian banks.\nThen on December 4, pro-government analyst <PERSON> told the state news agency BELTA: “Since the 1990s when Belarus was threatened with sanctions, the country created its own domestic banking system, Belkart. We’re also plugged into the Russian system. We’re connected to the Chinese system. At present, SWIFT has no monopoly on enabling monetary operations.”\n“On the other hand, Belarus’ disconnection from SWIFT will deliver a most powerful blow to the Belarusian radical opposition… because the opposition will not be able to get funding via bank cards”, concluded <PERSON> in the same interview.\nThe Golos platform dismisses these arguments, stating that “the Russian system that was created as a backup for Russia’s own SWIFT disconnect will not help.", "704" ], [ "Uzbekistan releases its “last detained journalists” · Global Voices\n<PERSON>, Uzbek journalist. Photo by Radio Ozodlik\nOnce known as one of the world’s most despotic regimes, Uzbekistan continues to move closer to a free society since new president <PERSON> came to power in September 2016.\nOn May 7, 2018, the former Soviet Central Asian republic freed two journalists, <PERSON> and <PERSON>, who were detained in September and October 2017 for “anti-constitutional activities”.\nThe Committee to Protect Journalists welcomed this move by the Uzbek authorities and declared that for the first time in last two decades there are no journalists left behind bars in Uzbekistan. Other international organizations also expressed their approval of the move. The international community had been keeping a special eye on this case, as it was the first time since the arrival of Uzbekistan's new president that journalists had been detained in the country.\nThe OSCE Representative on Freedom of the Media, <PERSON>, welcomed their release and urged that “all remaining charges should be dropped.”\nSince the collapse of the Soviet Union, Uzbekistan had been ruled by the iron-handed <PERSON>, until he died in September 2016. <PERSON>’s long-serving Prime Minister <PERSON> replaced his late boss, launched some economic and political reforms at home, and catalyzed changes in regional integration.", "148" ], [ "Among the political changes was the release of several political prisoners who had served decades in prison. According to the Committee to Protect Journalists, five journalists, not including the two released this week, were also freed in the past one and a half years.\nIt was during this period of political reform that journalists <PERSON> and <PERSON> were detained on the same charges <PERSON> regime had used to imprison political opponents and journalists for years. The outcome of this case would show whether President <PERSON> was committed to continuing his reforms and an open-door policy or just temporarily playing the role of “good cop” to win people’s support for his internal political battles.\nThe detained journalists were charged with writing articles calling for the violent overthrow of the regime in Uzbekistan under a pseudonym. The journalists recognized that their articles had raised problems, but denied that this included calls to violence.\nWhen security forces officers in charge with investigating the case became themselves embroiled in a power struggle between the powerful former head of Uzbekistan’s security forces, <PERSON>, and the new president <PERSON>, many hoped that the journalists <PERSON> and <PERSON> would be freed.\nOn May 7, the court acquitted <PERSON> of all charges, but found <PERSON> guilty of “extremism”, sentencing the journalist to three years of community service. The judge released both directly from the courtroom.\nMinutes after breathing in the air of freedom and hugging his family members, <PERSON> gave an interview to his local colleagues, saying:\nThe fact that I am free now, and the fact that the court hearing was open, are fruits of the liberal politics of the President <PERSON>.\nUzbekistan, like many other former Soviet republics, is a country where even small political moves are subject to the ruler’s approval.\nAs CPJ Europe and Central Asia Program Coordinator <PERSON> commented:\nNow that the country has freed its press from physical custody, authorities must build on this progress to ensure that the media are able to do their job independently and without fear of reprisal.", "409" ], [ "With Economy Unravelling, What Awaits the Turkmen Regime? · Global Voices\nPhoto taken in Ashgabat in 2007 by <PERSON>. Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.\nOn June 7, Turkmenistan's all-powerful president ordered a stripping away of the generous subsidy system that gives local people a reason — asides form fear — to tolerate their grandstanding, totalitarian resource-rich government.\nCitizens have enjoyed effectively free water, electricity and gas from the early days of independence from the Soviet Union. Now there will be no more freebies for citizens of the country with the world's fourth biggest gas reserves, behind only Qatar in reserves per capita.\nThe reason? An energy price-linked financial crisis, which has also seen the local manat currency sharply depreciate, the cost of imported foods and other goods spike and shortages pop up all over the economy.\nAs <PERSON> a PR-Director at neighbouring Kazakhstan's Kazakhfilm company, wrote:\nКажется, Туркменистан почти всё. Добрались костлявые руки углеводородного кризиса до родины башизма. Ждём появления центральноазиатской Венесуэлы.\nThis is the end for Turkmenistan. The crisis has reached the country. Now we’ll see the appearance of the Central Asian Venezuela.\nPetro-dollars dry up\nSome of the parallels thrown up by <PERSON>'s comment are interesting to ponder.\nLike Venezuela, Turkmenistan's economy is very undiversified, with hydrocarbons accounting for over 90% of both countries’ exports.", "148" ], [ "Like Venezuelan President <PERSON>, Turkmen President <PERSON> came to power following the death of a more charismatic predecessor. Finally, both <PERSON> and <PERSON> have found their governments increasingly unable to meet the basic needs of their populations and pay wages on time as energy profits have shrunk.\nYet in other ways, the two countries are very different. While Venezuela has slid deeper and deeper into authoritarianism amid a profound economic, social and political crisis, Turkmenistan has long been a totalitarian state with rubber stamp political institutions and courts unworthy of the name. In Reporters Without Borders press freedom rankings Venezuela places 137th out of 180 countries, while Turkmenistan places 178th. The Central Asian country's internet is among the most restricted in the world.\nWith political opposition, independent sources of information and the civic space almost completely invisible in Turkmenistan, it seems unlikely that the <PERSON> regime can be troubled by the sort of protests that have dogged the <PERSON> regime and seen it resort to brutal violence against protesters. The democratic institutions that <PERSON> has aggressively sought to erode in Venezuela, by dissolving and then weakening the national assembly dominated by opposition, and by stuffing the judiciary with loyalists, have simply never existed in Turkmenistan.\nBut that does not mean that the Turkmen regime does not have dark days ahead of it, as a nadir mostly of its own making continues to deepen.\nBig spenders on unnecessary things\nSharing responsibility for the country's economic malaise along with low oil and gas prices and systemic corruption is the Turkmen government's propensity to spend wastefully on vanity projects. A new falcon-shaped airport in Ashgabat set the government back more than $2 billion and is reportedly sinking into the ground. The Central Asian state is also spending billions of dollars on hosting a B-list sporting tournament, the 2017 Asian Indoor and Martial Arts Games, that it committed to before the oil price crisis began, with whole communities reportedly being forcibly displaced for the purpose of building infrastructure ahead of the games.\nThese projects — rather than state subsidies — are apparently the new priorities for a government that claims citizens are living in the era of “supreme happiness and the stable state.”\nWriting on Facebook, Azerbaijani <PERSON> suggested that the extent of the economic downturn in the country means they will soon be living somewhere else entirely, joining millions of citizens from other Central Asian states earning a living abroad in order to feed their families.", "704" ], [ "Building an Internet Fast Lane in Russia Could Be a Great Way to Stifle Independent Media · Global Voices\nThe net neutrality paradise of information equality may be coming to an end in Russia. Images mixed by <PERSON>.\nThe Federal Anti-Monopoly Service (FAS) may soon allow Internet Service Providers to collect fees from websites willing to pay a premium for prioritized content delivery.\nThe popularity of websites and services content requiring high bandwidth, like YouTube and Skype, has led to a dramatic increase in the amount of data traveling through the Internet, FAS says. The increased load on Russia's telecommunication network necessitates new investment in the national infrastructure, but ISPs complain that they're short on funds.\nAs is the case around the world, Russian Internet service providers are vocal opponents of net neutrality, which exists in Russia largely de facto, without being legally enshrined. Rostelecom, a leading local telcom that is majority-owned by the Russian government, has blamed Skype for gobbling up too much of its bandwidth and in turn allowing users to make calls for “free,” rather than using Rostelecom's telephone services. According to the company, customers’ use of Skype cost it 6.7 billion rubles ($166 million USD) in 2009 alone.\nAlthough network neutrality is not explicitly protected under Russian law, Russian ISPs effectively treat all Internet traffic equally when it comes to its “size” or the amount of bandwidth it requires for transport.", "534" ], [ "It should be noted that Russian ISPs do block some traffic on political grounds—a practice that goes against the principle of net neutrality, which is to treat all traffic equally, without exception.\nDetails about the plan to end Russian net neutrality are still few and far between. So far, FAS has merely submitted its proposal to the government, which will deliberate for nobody knows how long. In fact, FAS’ announcement itself was quite unexpected. Just a few months ago, agency head <PERSON> expressed his support for the principles of net neutrality, saying that ISPs should treat all content equally.\nИ мы можем ещё раз подчеркнуть, что ликвидация мобильного рабства, технологическая нейтральность, сетевая нейтральность, конкуренция между стационарной электросвязью, развитие её с мобильной и так далее являются фундаментальными вопросами, о которых мы мечтали 10 лет.\nWe can stress once again that the end of “mobile slavery” [the introduction of portability for mobile telephone numbers] and the arrival of technological neutrality, Net neutrality, competition between landlines and mobile networks, and so on, all represent fundamental things we dreamed about for the last decade.\nNow, however, FAS officials are citing the Federal Communications Commission in the United States for arguments against net neutrality. FAS’ new proposal would require ISPs to maintain a service “baseline,” but companies would be allowed to charge more money to deliver faster speeds for premium content.\nNet neutrality remains an unresolved issue in the US, as well, where the FCC's position seems irresolute, despite President <PERSON>'s statement on October 9 that he opposes “creating two or three or four tiers of Internet.” When it comes to Internet regulations, Russian officials often model policy on approaches tried in the United States. By “copycatting” the US, Moscow is able to defend itself as “behaving like the Western democracies.”\nDepending on what the FCC does with net neutrality, Russia's FAS might need to reexamine its justifications for policy reform.\nIn Russia, where the online space for independent media is fast shrinking, the prospect of filtering Internet content poses additional dangers.", "704" ], [ "Former Ukrainian PM <PERSON> Officially Supports #Euromaidan Movement · Global Voices\nAccording to her official website, former Ukrainian Prime Minister <PERSON> has officially joined the Maidan Civil Movement, a newly formed civilian organization stemming from the Euromaidan movement, just as the protest that began in Ukraine in November 2013 enters its second month.\n<PERSON>, jailed in 2011 for allegedly “exceeding authority”, is considered by many around the world to be a political prisoner, while Ukrainians are divided on their opinions of her. Most Ukrainian citizens condemned her imprisonment in 2011, some claiming that the current regime's only reason for doing so was to remove her from politics after current Ukrainian President <PERSON> won the 2010 presidential election, with <PERSON> as his opponent in the run-off round, by just 3.5 percent.\nIn a YouTube video posted by Ukrainian Channel 5 and released on <PERSON>'s official site, the founders announce the new Maidan Civil Movement's inception before thousands of protesters gathered in Kyiv's Independence Square:\n<PERSON>'s photograph has been gracing many posters and billboards related to the Euromaidan protests in recent weeks, and the jailed former prime minister's daughter has recently, along with other supporters, demanded the immediate release of her mother amid the growing anti-government demonstrations in the country. Other protesters are requesting that <PERSON>'s image be removed from any Euromaidan-related visual materials, not explicitly against <PERSON>'s person and image, but rather as a continuous request by the civilian movement to keep the protests unrelated to any political party or figure.\nA recent post titled “<PERSON> Isn't Who You Think She Is”, Policymic.com explains <PERSON>'s role in the country and the on-going protests:\nOngoing protests are not about <PERSON>. Although, how she was treated has further undermined people's trust in the president and his regime, and this is reflected in their calls to keep politics (existing slogans of political opposition) out of Maidan.", "534" ], [ "As an example, a petition was recently started on Avaaz to remove her portraits from the infamous Christmas tree. Currently, people see existing political opposition, including <PERSON>'s “Fatherland” party, as part of the political problem rather than its solution. However, as of yet, the civil society is unable to offer new leaders of their own. A workable solution will have to come from their collaboration, but an effective recipe has yet to be found.", "339" ] ]

[ 4247, 6802, 3932, 10955, 3981, 6364, 11122, 11373, 130, 3895, 5678, 4263, 4269, 5439, 9524, 3900, 7273, 9043, 2978, 10837, 11344, 1683, 5946, 2472, 5134, 11025, 5155, 8657, 4834, 5468, 6296, 843, 4777, 2794, 3846, 5238, 2517, 2492, 497, 7690, 10810, 8756, 2875, 7007, 6075, 8317, 8607, 6397, 3294, 1838, 5304, 8385, 4735, 10871, 414, 11255, 2073, 10153, 4372, 10509, 8476, 4106, 3615, 5036, 8534, 5284, 3030, 746, 11051, 1664 ]

[ [ "Tunisians left to themselves to fight COVID-19 · Global Voices\nA woman in the subway in Tunisia during the COVID-19 pandemic. Photo by <PERSON> CC BY-SA 4.0\nSince April, Tunisia has faced a sharp rise in the number of COVID-19 cases and deaths. The Ministry of Health described the health situation as “very dangerous ” with hospitals being at almost full capacity. To flatten the curve, the authorities—again—announced new containment measures that include a national curfew, school closure, travel restrictions. But few believe it will be enough.\nUnlike wealthy countries, there are no relief schemes to support workers and businesses to stay afloat. With unemployment already high and the cost of living skyrocketing, the most vulnerable have barely received ad-hoc small state assistance, and people are left to fend for themselves to survive. Therefore, the prospect of catching the virus is less of a concern than the necessity of carrying on and making a living.\nThough Tunisia imposed a stringent lockdown at the onset of the pandemic and for a while kept the spread of the virus low at a high price for the economy, there is now a wide feeling of powerlessness and fatigue. “If I don’t go out and work who is going to give me money?” asked <PERSON>, a Tunisian builder who, like the majority of workers, relies on daily earnings.\nUnable to respond to the demands of the population and drowned in their own political disagreements—Tunisia has had nine governments in 10 years since the revolution —there is complacency at the top. The authorities are not enforcing COVID-19 measures: political rallies have continued to gather large crowds flouting health protocols; social distancing and masking are ignored; cafés and markets are crowded. Digitalisation having lagged, many office and administrative work is still done on-site using hard copies.\nSince independence in 1956, Tunisia has heavily invested in its infrastructure. The public health system grew rapidly to provide universal health coverage that used to be the pride of Tunisians. But in the Nineties , corruption, deregulation in favour of the private sector resulted in a downward spiral of deterioration of public health services. It has only worsened throughout the years.\n<PERSON>, a medical intern told the Anadolu Agency that “the health sector is now in crisis not only because of the pandemic but also due to many infrastructural problems which have remained unresolved in recent years.”\nTunisian Prime Minister <PERSON> visiting a hospital in Sousse in December 2020.", "1019" ], [ "Photo from the official Facebook page of the Presidency of the Government of Tunisia, Public Domain.\nIn 2014 and 2018, medical professionals launched two general strikes after scandals at hospitals that took the lives of 15 newborns babies and the death of a young doctor in a lift accident . Prime Minister <PERSON> pledged at the end of December 2020 the creation of a national body for public health reform. But it is an issue that will take a long time to fix.\nIn the meantime, Tunisians who can afford it are turning to a largely unregulated and mushrooming private sector for treatments.\nPrivate health care for those who can afford it\nCOVID-19 has exacerbated the dysfunction of the public health care system. It starts by being able to access a COVID-19 test. While the WHO’s director recommended testing at the onset of the pandemic, Tunisia has never had enough testing capacity.\nIf, in theory, PCR tests are free at public hospitals, there are not enough tests available in reality. Most people will not be able to be diagnosed. The private sector is called to fill the gap but with a high price tag that is unaffordable for most Tunisians. At the beginning of the pandemic, some laboratories were charging 400 dinars (145 United States dollars) for a PCR test which is almost the equivalent of the Tunisian monthly minimum wage. The government intervened to cap it at 209 dinars ($76) and then to reduce it further to 170 dinars ($62).\nTunisian Ministry of Health Facebook announcement with photo of Health Minister Dr. <PERSON> and a quote, “We agreed with laboratories to reduce the cost of PCR test.” Public Domain.\nAt this price tag, it is unlikely many people will get tested. Mainly travelers are taking the test as more and more countries require negative PCR tests for entry. There have been numerous stories of test results trafficking—people buying forged certificates at a cheap price on the black market. The government has clamped down on the traffic, now requiring laboratories to have a QR code on test results.\nTunisia's lack of testing is in stark contrast with most wealthy countries, where testing is free and at the center of their recovery strategies. For instance, the UK and France will offer free rapid COVID-19 tests when lifting their lockdown.", "1019" ], [ "To save its economy, can Tunisia reform its oversized public sector? · Global Voices\nGovernment buildings in Tunis, the capital of Tunisia. Photo by <PERSON> on Wikimedia (CC BY-SA 2.0)\nRecruitment of public servants has increased massively in Tunisia since the 2011 revolution. Now the economic downturn is pushing the country towards reform in an effort to cut public expenditure.\nTunisia’s economy was already in bad shape, after decades of low wages and high unemployment, which were the root causes of the “Jasmine Revolution.” The COVID-19 pandemic has made things worse, increasing the lack of jobs and deepening the crisis. Mired in debt, the Tunisian government is now turning to the International Monetary Fund (IMF) for a bailout of 4 billion United States dollars. According to the prime minister, <PERSON>, this is the “last opportunity” to save the country’s economy, but it is conditional on Tunisia reforming its economy and reducing its public sector wage bill and subsidies.\nTunisia is regularly acclaimed by Western governments as being the Arab Spring success story, but the state of its finances is threatening the political transition to democracy. The country has accumulated a chronic deficit estimated at 11.5 per cent of gross domestic product and public debt at 90 per cent of GDP. The payment of public salaries represents over half of state spending and is among one of the highest in the world, in comparison with the size of the Tunisian economy, according to an IMF study.\nThe high price of ‘social peace’\nThe number of public servants has grown exponentially, almost doubling since the revolution. One after the other, successive governments have used public jobs to appease public discontent. “Work, freedom and dignity” have been unabating key demands of Tunisian youth frustrated by widespread corruption and lack of opportunities. With the right to work with dignity and a fair wage enshrined in the constitution, governments have been under pressure to create jobs. In the absence of a robust economic plan and a welfare state, people have been recruited in public administrations not based on a need but in response to protests for jobs and social justice. <PERSON>, former minister of the public sector, stated that governments hired people to buy “social peace.” Street protests across the country by unemployed youth demanding their “rights for development and work” in Kassrine, Tataouine and other towns resulted in promises of public employment.", "803" ], [ "This culminated in 2020, when following months of protests by Tunisian graduates, the parliament adopted a bill guaranteeing all those who had been unemployed for at least a decade to be recruited by the public sector—though it is not clear how and whether these measures will be implemented.\nAs well as responding to the demand for jobs, hiring in the public sector was also used for other partisan political motivations. Many have been accused—in particular, the Islamist party Ennahda—of having massively recruited among their partisans and loyalists to ensure their consolidation of power. Under the previous regime of <PERSON>, the Islamists were the main opposition and were persecuted and banned from power. After decades of oppression, public tenure was seen by the new post-revolution leadership as a fair reparation and compensation for their past exclusion. The biggest surge in public hiring took place during the rule of the “Troika” alliance between 2011 and 2014, led by Ennahda. According to the Tunisian Union of Public Service and Administration Neutrality (UTSPNA), “Ninety per cent of appointments in the public sector under the Troika were made on the basis of partisan, regional or family orientations.” Ambassadors and consuls, governors, magistrates and managers in strategic areas such as the media, security and IT were recruited among the party supporters, reports said. A controversial amnesty law was also adopted in 2012 granting public sector jobs to over 7,000 people who were wounded in the revolution, as compensation and recognition of their sacrifice.\nIn an interview with me <PERSON>*, a young engineer said, “Successive politicians have contributed to deepening corruption. They have turned the administration into a dysfunctional mammoth uncapable of fulfilling its primary functions. These populist short-sided measures are a recipe for disaster.”\nDeterioration of public services and increase in wages\nUnder pressure from the powerful General Union of Tunisian Workers (UGTT), the uncontrolled increase in the number of public servants has been coupled with an increase in salaries. According to a study by the National Institute of statistic (INS), salaries rose by 23.18 per cent between 2011 and 2015, with the highest increase being under the Troika in 2013. This combination has led to a sharp rise of the public wage bill in an already strapped state budget. The increase in staff and salaries, however, hasn’t resulted in better performance, quite the opposite. Most public services—education, health, security etc.—have deteriorated.", "906" ], [ "COVID-19 has accelerated digitalization but will Tunisia log on? · Global Voices\nTunis city hall. Photo from Wikipedia in the public domain.\nSeen from afar, Tunisia has all the favorable conditions for digitalization, including effective and affordable internet access and a largely young and highly connected population. Yet, the nation still lags behind in the digitalization of all its services, both public and private, due to decades of corruption and government inaction.\nWhen COVID-19 hit Tunisia in March 2020 , the government enforced a strict lockdown, exposing a fragile, largely traditional economy. But a flurry of innovations mushroomed, ranging from telemedicine and telework to online entertainment and education. Staff began to work remotely and the government started to use robotic and digital technology.\nIn this way, COVID-19 accelerated digitalization in Tunisia like no previous government could achieve, gaining more digital momentum in a single month than it had in prior decades.\nFor <PERSON> , chairman of the Joint Public-Private-Civil Society Committee for digitalization, the pandemic crisis led to the equivalent of a “fall of a Berlin Wall” moment between the administration and the Tunisian digital industry.\nCan the COVID-19 pandemic continue to act as a catalyst to accelerate its online economy and services?\nAmbitious plans — delayed\nDigitalization, the process of collecting, storing and sharing information online, allows for more transparency and evidence-based policies essential for good governance.\nAs former Prime Minister <PERSON> noted in 2019: “Digitalization is the best weapon to fight corruption,” echoing international consensus.\nIn 2018, the government launched the National Strategic Council for the Digital Economy ( CNCEM ) with an ambitious “ Digital Tunisia 2018 ” framework to create a conducive digital ecosystem. With an overall allocated budget of $867 million United States dollars, the digitalization plan envisioned the creation of over 100,000 jobs . But plans have been slow to implement or totally delayed. “Digital Tunisia 2018” became “ Digital Tunisia 2020 ” before being once again postponed to 2025.\n<PERSON> , Tunisian minister of Technology, Communication and Digital Transformation, admitted in May during the lockdown that “almost half of the projects in the ‘Digital Tunisia 2020’ strategic plan have not yet seen the light of day,” and shifted the program to a new “ Digital Tunisia 2025 .”\nA series of setbacks\nTunisia was among the first to promote technology in the region and the aim to digitalize the nation is nothing new.", "803" ], [ "Its digitalization plans date back to 1999, when a national e-commerce commission was created to oversee the development of the sector.\nIn 2005, Tunisia hosted the World Summit on the Information Society ( WSIS ) that aimed to bridge the global digital divide separating rich and poor countries. It resulted in the adoption of pioneering bills with the Tunis Commitment , the Tunis Agenda for the Information Society and the creation of the Internet Governance Forum .\nBut these grand announcements were not followed by concrete actions and plans took years to materialize. In 2012, a public-private task force was formed to revitalize the sector and draft a digitalization roadmap, but these plans continue to stall, despite Tunisia’s modern fiber-optics infrastructure.\nThis delayed digitalization is symptomatic of a political stalemate in Tunisia, where authorities pioneer the adoption of forward-thinking legislation but struggle with their implementation. Political decisions made at the top often remain invisible on the ground, fostering frustration and discontent.\nIn 2011 , youth took to the streets in protests that demanded calls for immediate, structural reforms, but these calls were not heard and after almost a decade, the situation remains unchanged for many and for some — even worse.\n“Since the revolution, we have freedom but not dignity,” said <PERSON>, a young unemployed Tunisian IT engineer in a le Point article .\nYouth unemployment has risen to 36 percent and corruption is also on the rise. The economy is still fueled by labor-intensive jobs like farming or manufacturing, alongside a bloated government bureaucracy that, in 2018, employed nearly 800,000, accounting for 46 percent of the national budget .\n“Tunisia has been applauded for its peaceful transition and not falling into civil war like its neighbors in the region,” said <PERSON>, a retired Tunisian engineer who spoke to Global Voices:\nThe dark side of the acclaimed consensus politics, between secular and Islamist, is that it has merely postponed rather than resolved deep-rooted issues. Donors’ money has flooded the push for institutional reforms that failed to materialize in the life of the population. It has rewarded the status-quo. Since then we are stagnating.\nTunisia pays a high price for its stagnation.", "803" ], [ "Fighting COVID-19 goes hand-in-hand with shuttering newspapers across the Middle East · Global Voices\nA man reads the paper in Morocco on January 11, 2010. Photo by <PERSON>, CC BY 2.0.\nCheck out Global Voices’ special coverage of the global impact of COVID-19.\nIn the “war” against COVID-19, a number of governments in the Middle East are banning print journalism “ until further notice .”\nThe media sector and press, in particular, were already in bad shape in the Middle East and North Africa region (MENA). Like elsewhere, years of falling revenues, digitalization, poor quality content and co-option by authorities have led to a decrease both in the number of printed newspapers and readership.\nCOVID-19 is the latest blow to the print journalism sector. With several governments across the region suspending print newspapers, printed media is a silent victim of the virus:\nMarch 17, 2020 : In Jordan, the Jordanian Council of Ministers suspended the publication of all newspapers “ because they help the transmission of the pandemic “.\nMarch 22, 2020 : In Oman, the Supreme Committee for Dealing with COVID-19 ordered all newspapers, magazines and other publications to cease printing and circulating. In Morocco, the Ministry of Culture, Youth and Sports, suspended all publication and distribution of printed editions because “ a large number of people use print paper on a daily basis, this contributes to the spread of the virus, making it necessary to ban the paper to protect the health of citizens .”\nMarch 23, 2020 : In Yemen, the minister of communications from the internationally-recognized <PERSON> government issued a decree suspending print newspapers as a preventive measure to prevent the spread of COVID-19.\nMarch 24, 2020 : In the UAE, the National Media Council has stopped the distribution of all print newspapers and magazines.\nThe succession of prohibitions, across the region, against print newspapers further destabilize further a fragile industry and cause a vacuum in information circulation.\nFor journalists already battling precarious working conditions, these shutdowns will inflict serious financial repercussions if not redundancy.\nThe Jordanian Syndicate of Journalists has called on the government to urgently support the sector and save the journalists. “Hundreds of journalists and workers in the print industry are without income and may lose their jobs,” the syndicate said, adding that the government should “find adequates measures that will allow print newspapers to resume [publication].’’\nA vendor known as <PERSON> sells books and papers in Rabat, Morocco, May 17, 2017. Photo by <PERSON> via CC BY-SA 4.0.\nFor readers, these measures negatively impact their right to access information.", "803" ], [ "The ban in Yemen, for example, has an even deeper impact as internet penetration is low at just 25% in 2019, — and mainly concentrated among youth in urban areas. It is not clear how and if print readership will shift to online media and who will fill in this vacuum.\nHaving access to reliable fact-based information is essential, especially during a crisis when people turn to the media to understand the situation and get practical information. Yet, most governments in the region — perpetuating old authoritarian practices — have instead attempted to control and restrict freedom of expression.\nIn reality, there is no evidence or correlation between the circulation of print newspapers and the spread of COVID 19. It has been deemed safe to receive packages such as newspapers, even from areas that have reported high cases of COVID-19.\nAccording to the World Health Organisation (WHO):\nThe likelihood of an infected person contaminating commercial goods is low and the risk of catching the virus that causes COVID-19 from a package that has been moved, travelled, and exposed to different conditions and temperature is also low.\nTherefore, decisions to shut down print papers is possibly politically motivated and not based on scientific evidence.\nOther countries affected by the COVID-19 pandemic have chosen a different approach. Even in Italy, the epicenter of the crisis with a death toll nearing 20,000 and quarantine rules strictly enforced, newspapers have continued to publish and print.\nIn France, also badly hit by the virus, newspaper vendors have been categorised as “essential business” and allowed to stay open. Different sectors, local councils, delivery companies, distributors have allied to ensure print newspapers are available to the public.\nIn the United Kingdom, the free daily Metro and Evening Standard print newspaper, widely distributed in tube stations to commuters, have lost a large audience with the lockdown. They are now distributing in supermarkets and delivering door-to-door.\nThese few examples demonstrate collective efforts to keep the public informed. The free flow of information is preserved and contributes to building resilience in a crisis.\nThe Middle East has not taken this approach.\nTheir response to major challenges like COVID 19 is a repeated scenario of repression and control.", "803" ], [ "Impoverished youth in the Middle East turn to cheap — sometimes deadly — alcohol · Global Voices\nPhoto of alcohol with inscription in Arabic. Photo by <PERSON> on Flickr used under Licence CC-BY-NC-SA-2.0.\nIn May, young Tunisians looking for a buzz by drinking homemade alcohol ended in tragedy.\nAt least seven youth died and 56 were hospitalized for alcohol poisoning in Kairouan, an ancient Islamic center about 130 kilometers from Tunis, the capital, and one of the poorest governorates of Tunisia, where nearly 40 percent live below the poverty line.\nA neighbor of one of the young people who died in a video uploaded on Facebook said:\nYoung people want to forget their situation. They don’t care about dying. In fact, they say sometimes they want to die. Look at their environment, at the poverty. We don’t even have roads; the water is dirty. We are not stupid, but we don’t have the means. We are forgotten by the authorities.\nThe parents of three brothers who died from the poisoning added :\nMy sons were unemployed. One of them was 37 and unable to get married and start his own life. We don’t even have toilets at home.\nThis is not the first time toxic homemade alcohol has killed young people in the Middle East.", "235" ], [ "Alcohol and drug use is on the rise in the region, where young people who can’t afford locally produced or foreign imports opt to drink homemade, methanol brews — strong concoctions mixed up by illicit dealers.\nMethanol — used for industrial and automotive purposes — is a highly toxic and potentially deadly substance that can cause blindness, kidney failure and seizures and death if consumed in high quantities.\nIslam prohibits the consumption of alcohol and many Arab countries ban or enforces strict regulations on its sale, but it’s still widely available, whether obtained underground or on shelves.\n#SputnikAnalyse | En Tunisie, le décès de sept personnes après la consommation d’alcool frelaté a provoqué beaucoup d’émoi. Hormis la tragédie, c’est la précarité de la population et l’indifférence de l’État qui sont pointées du doigt. @HanZbiss analysehttps://t.co/431FrwCdqa pic.twitter.com/izybyqM35q\n— Sputnik France (@sputnik_fr) May 29, 2020\nIn Tunisia, the death of seven people after consuming adulterated alcohol caused turmoil. Beyond the tragedy, it is the precariousness of the population and the indifference of the state that are pointed out.\nThe thirst for cheap booze\nThe Middle East region has the largest youth population in the world, with more than half under the age of 25, but it also accounts for the highest unemployment rates reaching 27 percent in 2019 . In 2011, youth-led protests — known as the “ Arabic Spring ” — erupted after years of frustration over social, economic, and political exclusion.\nA 2019 report by the Brookings Institution argues that this delayed transition to the work market affects “other pathways to adulthood, including marriage, homeownership, and civic participation.”\nYoung men, traditionally seen as breadwinners for their families, are unable to fulfill their social obligations.\nWithin patriarchal societies in Egypt, Lebanon, Morocco, and Palestine, men “face tremendous stress to be providers. Men are ashamed to face their families due to lack of money,” according to a BBC report on patriarchy in the Middle East.\nAlcohol flows freely in restaurants, bars and shops in the Middle East — for those who can afford it. In Libya, for example, a bottle of Chivas Regal in 2014 was available for US$100 whereas a homemade Libyan brew was only US$15 a liter.\nBut in these conservative countries — where drinking is expensive and also a social taboo — it can turn into a grim and risky endeavor. <PERSON>, a Tunisian activist, told Global Voices:\nHomemade alcohol is widespread among idle young people, especially in poor remote areas. But it only makes the news when it ends in tragedy.\nThe Alexandria Faculty of Medicine in Egypt reported that 5 percent of monthly poisonings are related to alcohol, a figure likely lower than the true scale. Due to social stigma, shame and fear, many methanol consumers do not go to hospitals for treatment unless they are in critical condition.\nTaboo: Caught between tradition and modernity\nAlcohol is widely available in the Middle East, but it remains a taboo with negative associations and connotations. Young people in these countries often struggle to balance traditional Islamic values with the desire to live a liberal, globalized lifestyle.", "244" ], [ "From counterterrorism to counter-COVID-19, governments use crises to impose continuous states of emergency in the Middle East · Global Voices\nA municipal worker disinfecting surfaces in the capital Tunis, Tunisia. Photo credit: Lost in Tunis blog [Used with permission].\nIn response to COVID-19, governments around the world have declared states of emergency, allowing them to take exceptional measures to contain the pandemic.\nLiberal democracies from the United States , Canada to European countries , Malaysia and South Africa imposed emergency measures that restricted mobility under lockdowns. Likewise, in the Middle East and North Africa (MENA), authorities declared states of emergency and imposed exceptional measures such as curfews and home confinement.\nIn a region plagued by decades of instability and conflict, authorities have long used exceptional and temporary emergency orders to justify repression and curb human rights. Based on this precedent, a number of governments are now using the coronavirus crisis to further crackdown on human rights — particularly freedom of expression.\nWhat is a state of emergency?\nWhen faced with an imminent threat such as disease or natural disaster, states can legally declare a state of emergency that allows authorities to temporarily exercise exceptional powers. This may include the suspension of basic human rights and freedoms such as restriction of movement or banning public gatherings.\nHowever, “governments must inform the population of its exact substantive, territorial and temporal scope and the related measures,” when activating these measures, according to the United Nations Human Rights Office of the High Commissioner (OHCHR):\nEmergency powers should not be a weapon governments can wield to quash dissent, control the population, even perpetuate their time in power. They should be used to cope effectively with the pandemic, nothing more, nothing less. says @UNHumanRights Chief https://t.co/xUufH1WJGc pic.twitter.com/LC40UJk1ut\n— Inter Press Service (@ipsnews) May 3, 2020\nUnder international human rights law, there are limits to what a state of emergency grants governments.", "827" ], [ "The OHCHR recommends that “all measures taken during emergency rules to be proportionate and limited to those strictly required by the exigencies of the situation. (…) The military should not conduct policing functions.”\nCertain basic human rights cannot be suspended. These include “the right to life, the prohibition of torture and ill-treatment, the prohibition of discrimination, and freedom of religion, as well as the right to a fair trial and freedom from arbitrary detention and the right to judicial review of detention,” said Human Rights Watch on March 20, in response to Jordan's declaration of a state of emergency.\nMENA quick to declare emergency powers\nIn the MENA region, governments were quick to react and exercise full powers, even when there were only a few COVID-19 cases.\nOn March 5, Palestinian President <PERSON> declared a 30-day state of emergency after coronavirus cases were reported in the city of Bethlehem . On March 13, Mauritania followed suit and declared a state of emergency after the first case in the country was reported.\nOn March 16, it was Sudan ’s turn to declare a state of emergency, following the death of a COVID-19 patient. The next day, Jordan’s King <PERSON> issued a royal decree granting his prime minister sweeping powers , including the ability to “monitor the content of newspapers, ads, and any other method of communication prior to publication, and to censor and shut down any outlet without justification.”\nIn Morocco , on March 20, King <PERSON> declared a state of emergency, allowing the government to “take all necessary measures to combat the COVID-19 epidemic.”\nGovernments were able to quickly adopt exceptional measures, imposing general lockdowns and curfews, banning gatherings, shutting down schools, businesses and courts by decrees without parliamentary or judicial oversight.\nTemporary to permanent\nWhile these measures may be justified to contain the spread of the virus, emergency powers carry an inherent risk of undermining the rule of law.\nIn MENA in particular, governments and authoritarian regimes have a record of abusing the state of emergency status to suspend democratic institutions and human rights over long periods.\nFor example, a number of governments in the region have previously exploited the “war on terror” to extend their powers, turning what was supposed to be a temporary state of emergency into a permanent one lasting for decades.\nAlgeria was under emergency rules for nearly 20 years following a brutal conflict with Islamist militants in the1990s. Peaceful protests were barred, political freedoms were repressed, the media was censored and arbitrary detentions were common. It was only lifted in the wake of the Arab spring in 2011.\nEgypt was under a continuous state of emergency for three decades following the 1981 assassination of former President <PERSON>. Protesters demanded to lift the emergency status during the Arab Spring and finally succeeded in 2012.", "409" ], [ "Is Censorship Coming Back to Tunisia? Court Order Bans ‘Blue Whale’ Online Game · Global Voices\nThe investigation of mysterious groups on VKontakte full of images of whales and butterflies that Novaya Gazeta claims drive teenagers to take their own lives has met with public criticism. Image from VKontakte.\nA Tunisian court has ordered authorities to censor two online games that allegedly lead teenagers down a path to suicide. The issue has raised public concerns about self-harm — but also about arbitrary internet censorship.\nThe ruling calls on the Tunisian Internet Agency (known by its French acronym ATI) to block access to the Blue Whale Challenge and Mariam games, even though ATI has no legal mandate to block online content.\nThe Blue Whale Challenge is a decentralized online game where players are instructed to carry out specific tasks that include self-harm. After fifty days — in some documented cases — they are told to commit suicide. Mariam is a Saudi-developed horror-game that revolves around a lost girl, whom players help guide back home.\nApart from the fact that this would take ATI beyond the bounds of its legal mandate, the court order to “block” Blue Whale Challenge also fails to acknowledge the decentralized nature of the game. Blue Whale is not hosted on a single platform, but is instead orchestrated by various anonymous administrators interacting with players in private social media chat groups.\nThe game first came to prominence in Russia in mid-2016 after it allegedly resulted in cases of suicide and attempted suicide across a number of countries. Through a variety of legal measures, authorities in Russia, Kazakhstan and Kyrgystan have all attempted to reduce children's access to the game by shutting down VKontakte groups where the game is hosted, alongside other groups that are seen as promoting self-harm.\nIn 2017, when the game became popular in China, major social media platforms like Baidu and Sina Weibo began shutting down all the forum discussions with keywords like “Blue Whale” or “Blue Whale game”.\nTunisian authorities respond to public fear over Blue Whale\nOnly recently has the game risen to prominence in Tunisia. Last December, the National Agency for Computer Security (known by its French acronym ANSI) warned parents against the Blue Whale Challenge.", "534" ], [ "While recalling that it cannot block any online content as it is not part of its mission, the agency advised parents to use parental control software, despite the limitations of this solution, given the game's decentralized nature.\nIn March , five Tunisian teenagers who are believed to have played Blue Whale committed suicide. Their parents, who found their children hanged in their rooms, say they died because of their addiction to these online games. Three others attempted suicide but were saved in extremis.\nIn February, the parents’ association of a local school and the delegate for child protection in the city of Sousse filed a lawsuit to order the Tunisian Internet Agency to block access to the two games.\nIn a verdict issued on 6 March 2018, the Court of First Instance (primary court) of Sousse ordered the ATI to block access to the two games, arguing that they represent a danger to youth in the country.\nThe implications of this decision, if upheld on appeal, would set a new precedent for internet censorship in Tunisia. If the final judgment is in the plaintiffs’ favor, it will obligate the agency to censor the two games. Even though this might be technically impossible in the case of Blue Whale, it would constitute a jurisprudence on which other requests for content censorship — that could be much more clearly detrimental to the public interest — could be based.\nEchoes of the <PERSON> era?\nThe ATI was once known as the censorship body of the dictatorship of ousted president <PERSON>. Established in March 1996, the agency’s official mandate was to develop the internet in Tunisia beyond being the only gateway for international connectivity as an internet exchange point. But at the same time, and until the revolution, the ATI had orders from the presidency and government to control all online information , even though it had no legal mandate to censor content or spy on users.\nAfter the public uprisings and consequent ousting of <PERSON> in January 2011, interim authorities ended internet censorship practices and the ATI adopted reforms to cut ties with its image as an internet censor by focusing only on the legal mandate it was first established to fulfill. Lawsuits like these would undermine such reforms, potentially sending ATI back to a position of censor.\nAnd this month’s court decision is not the first attempt to bring back online censorship, in post-revolutionary Tunisia. In May 2011, a group of plaintiffs represented by three lawyers prosecuted the ATI to ban access to online pornographic content, also on the grounds of child protection.\nATI appealed the court decision, which they lost in August of the same year.", "409" ], [ "COVID-19: Switching online is not an option in conflict-stricken countries in the Middle East · Global Voices\nStreet scene in Sana'a, Yemen, where the majority of those with internet access are young men, April 28, 2015. Photo by <PERSON> via Flickr by CC BY-SA 2.0.\nThe COVID-19 pandemic has forced governments across the world to impose lockdowns, sending billions of people into home confinement. This exceptional situation has caused a lifestyle paradigm shift.\nWorking, learning and socializing online has become the norm, as people severely restrict their time outside to limit any prospects of catching the novel coronavirus.\nThe use of the internet is not new, but COVID-19 fast-forwarded this global shift where the internet dominates all aspects of life for those who have access to it.\nIf online is the way forward in these times of a pandemic, what about countries stricken by conflicts with limited internet access?\nCOVID-19 accelerates digital transformation\nThe COVID-19 pandemic and the unprecedented measures taken to stop its spread have changed our lives. It has led to fundamental shifts in how societies and businesses operate.\nAs the deadly virus disrupts the world and may continue to do so until a vaccine is discovered, the internet has taken over. Studies show that internet traffic has surged by between 50 percent and 70 percent since COVID-19 began.\nTrapped at home, people turned to the internet en masse to continue their daily routines including shopping, working and learning, communicating and socializing. This will likely have a lasting impact well after the pandemic ends.\nA deepening digital divide\nThe internet is widely available and provides a lifeline in wealthy countries during COVID-19, but this is not the case for almost half of the world’s population, which has no internet access . The majority of this population lives in poor, war-stricken countries where infrastructure is failing and yet, the need for information is most urgent.\nIn conflict-stricken countries, many citizens face this additional crisis without the internet. Meanwhile, in wealthy, peaceful countries, the internet has enabled citizens to mitigate the impact of lockdowns by allowing them to continue to work, study, communicate, socialize and access information.\nIn some countries in the Middle East and North Africa (MENA), COVID-19 struck at a time of economic crisis, and wide-scale conflict or uprisings. Years of conflict in Yemen, Syria, and Libya have brought immense suffering, displacement and destruction.", "803" ], [ "Infrastructure has been targeted by warring parties with disregard for civilian life.\nIn Syria, for example, over 50 percent of the infrastructure is no longer operational .\nIn Libya, much of the telecom infrastructure has been destroyed or stolen, including about a quarter of the country’s mobile tower sites. As a result, basic services — electricity, sanitation, water and the internet —have been brought to a standstill.\nIn Yemen, labeled by Relief Web as the world's worst humanitarian crisis, internet access is a major obstacle. Only about 27 percent of Yemenis , mainly young men located in urban areas, have internet access.\nThe majority of youth are striving to find ways to connect to the external world. “The internet is our oxygen and is as important as food. I moved from my town to the capital to be able to connect,” said <PERSON>, a Yemeni journalist who asked Global Voices only to use his first name.\nWomen in the region are disproportionally affected by this digital divide. Fewer women have access to the internet than men, which reflects a regional gender inequality gap with Yemen, Syria and Libya ranking near the bottom of all countries.\nA combination of conservative social norms, less access to learning and financial resources and a hostile online environment impede women’s ability to connect and access information online and minimizes participation in online discussions.\nThe internet: High cost, low speed and unreliable\nIn Libya, Syria and Yemen, strained by conflict and economic chaos, users face low-speed internet and prohibitive costs.\nYemen has the slowest internet speed globally with an average speed of just 0.38 megabits per second in 2019: It would take over 30 hours to download a 5-gigabyte film. In January 2020, damage to a submarine cable plunged Yemen into an internet outage for over a month.\nThe COVID-19 pandemic has forced massive school closures , affecting 90 percent of the world's student population, which has led to a culture of virtual learning, online education, but learning proves nearly impossible without a reliable, high-speed internet connection.\nThis also prevents people from communicating and journalists from reporting and reaching a large audience . L ow speeds make it difficult to browse, download or upload materials and communicate with sources. It also deprives access to valuable resources critical to writing reports, news stories and daily events.", "803" ] ]

[ 9017, 542, 11281, 2214, 11370, 2492, 6469, 7690, 6476, 9796, 9375, 3398, 6299, 1106, 7399, 10279, 3186, 9034, 9991, 130, 9156, 9207, 6802, 9294, 5678, 9599, 2699, 9122, 5641, 2978, 9861, 10450, 497, 3776, 2875, 2919, 8657, 3780, 4596, 2571, 1617, 9524, 6623, 2477, 6506, 2892, 8403, 8756, 889, 6133, 6807, 6831, 6192, 6719, 5351, 4263, 8885, 9113, 10585, 8214, 8461, 20, 10326, 9909, 3330, 5974, 9672, 2472, 7147, 3698 ]

[ [ "In Chukchee mythology, according to <PERSON> (1907), the Aurora Borealis is made of the spirits of the people who died a violent death. Some of them are playing soccer in the sky with a walrus head:\nThe Aurora Borealis is chiefly the place of abode for those who die a sudden or violent death. The whitish spots are the people who died from contagious diseases; the red spots are those stabbed with a knife; the dark spots are those strangled by the \"spirits\" of nervous diseases; the changeable rays are deceased people running about and playing ball with a walrus-head which is alive. It roars when in motion, after it has been tossed. It wants to strike with its tusks anybody who tries to catch it. Men who have been strangled with a slip-noose at their own request, have honorary places among the spectators; or they themselves may play, but do so in a very awkward manner, because of the rope dangling behind them on the ground.\n<PERSON>, 1907. The Chukchee – Religion (Part II). Memoirs of the American Museum of Natural History.\nThis narrative seems to be relatively widespread among Eskimo people since the Inuits from Labrador had similar beliefs:\nOnly the spirits of those who have died a voluntary or violent death, and the raven, have been over this pathway.", "919" ], [ "The spirits who live there light torches to guide the feet of new arrivals. This is the light of the aurora. They can be seen there feasting and playing football with a walrus skull.\nExtract from Aurora: the northern lights in mythology, history and science.\nThe soccer game with a walrus head was also rapported by <PERSON> for the Iglulik Inuits:\nHere, they are constantly playing ball, the Eskimos' favourite game, laughing and singing, and the ball they play with is the skull of a walrus. The object is to kick the skull in such a manner that is always falls with the tusks downwards, and thus sticks fast in the ground. It is this ball game of the departed souls that appears as the aurora borealis, and is heard as a whistling, rustling, crackling sound. The noise is made by the souls as they run across the frost-hardened snow of the heavens. If one happens to be out alone at night when the aurora borealis is visible, and hears this whistling sound, one has only to whistle in return and the lights will come nearer, out of curiosity.\n<PERSON>, K., 1929. The Intellectual Culture of the Iglulik Eskimos. Report of the 5th Thule Expedition 1921-1924.", "919" ], [ "Did the photo of a woman and a pony really exist?\nI found a rather interesting reference in Slaughterhouse Five by <PERSON>:\n<PERSON> had a block of balsa wood which was supposed to be a foxhole pillow. He had a prophylactic kit containing two tough condoms 'For the Prevention of Disease Only!' He had a whistle he wasn't going to show anybody until he got promoted to corporal. He had a dirty picture of a woman attempting sexual intercourse with a Shetland pony. He had made <PERSON> admire that picture several times.\nThe woman and the pony were posed before velvet draperies which were fringed with deedlee-balls. They were flanked by Doric columns.", "247" ], [ "In front of one column was a potted palm. The Picture that <PERSON> had was a print of the first dirty photograph in history. The word photography was first used in 1839, and it was in that year, too, that <PERSON> revealed to the French Academy that an image formed on a silvered metal plate covered with a thin film of silver iodide could be developed in the presence of mercury vapor.\nIn 1841, only two years later, an assistant to Daguerre, <PERSON>, was arrested in the Tuileries Gardens for attempting to sell a gentleman a picture of the woman and the pony. That was where <PERSON> bought his picture,, too-in the Tuileries. <PERSON> argued that the picture was fine art, and that his intention was to make Greek mythology come alive. He said that columns and the potted palm proved that.\nWhen asked which myth he meant to represent, <PERSON>, replied that there were thousands of myths like that, with the woman a mortal and the pony a god.\nIs there any mention of this event ever occurring? It is like <PERSON> to mix up fictional and non-fictional characters and events and this one definitely did fit in nicely in his cynical portrayal of humanity anyway.\nDoes anyone have any reliable info on this one? Could it possibly be that it took only two years after photography was invented that it was first used in pornography? Or maybe it was an existing urban legend? Or <PERSON> just made it up?", "321" ], [ "Short answer, no. There is no writing, inscription, artwork, statuary, or anything that indicates <PERSON> (or <PERSON>) was crucified.\nThere is death and resurrection in <PERSON>' story, though. The Metternich Stele relates the story of <PERSON> dying by the sting of a scorpion. <PERSON> has a nice summary:\nhttp://www.sacred-texts.com/egy/leg/leg11.htm\nNow soon after <PERSON> had restored to life the son of the woman who had shown churlishness to her, a terrible calamity fell upon her, for her beloved son <PERSON> was stung by a scorpion and died. The news of this event was conveyed to her by the gods, who cried out to her to come to see her son <PERSON>, whom the terrible scorpion Uhat had killed. <PERSON>, stabbed with pain at the news, as if a knife had been driven into her body, ran out distraught with grief. It seems that she had gone to perform a religious ceremony in honour of <PERSON> in a temple near Hetep-hemt, leaving her child carefully concealed in Sekhet-An.", "351" ], [ "During her absence the scorpion Uhat, which had been sent by <PERSON>, forced its way into the biding-place of <PERSON>, and there stung him to death. When <PERSON> came and found the dead body, she burst forth in lamentations, the sound of which brought all the people from the neighbouring districts to her side.\nA little bit later:\nThen he came to <PERSON> and told her that no harm could possibly have happened to <PERSON>, for he was under the protection of the Boat of Ra; but his words failed to comfort <PERSON>, and though she acknowledged the greatness of his designs, she complained that they savoured of delay. \"What is the good,\" she asks, \"of all thy spells, and incantations, and magical formulae, and the great command of maa-kheru, if <PERSON> is to perish by the poison of a scorpion, and to lie here in the arms of Death? Evil, evil is his destiny, for it hath entailed the deepest misery for him and death.\"\nIn answer to these words <PERSON>, turning to <PERSON> and <PERSON>, bade them to fear not, and to have no anxiety about <PERSON>, \"For,\" said he, \"I have come from heaven to heal the child for his mother.\" He then pointed out that <PERSON> was under protection as the Dweller in his Disk (Aten), the Great Dwarf, <PERSON>, the Great Hawk, the Holy Beetle, the Hidden Body, the Divine Bennu, etc., and proceeded to utter the great spell which restored <PERSON> to life.\nThinking of <PERSON> as a prefiguration of <PERSON> is a clear-cut case of parallelomania (warning: PDF). Unfortunately, with \"researchers\" like <PERSON>, sometimes the faint parallels (death and revival) become the overarching theme, hiding away any (especially major!) differences, and twists the rest of the narrative to fit. For example, this was not related to any divine soul-saving god, but rather to ancient Egyptian (religiously-based) medical practices. See <PERSON> 2002 Ancient Egyptian Medicine pp. 108–109.", "381" ], [ "Was it common that the bridges of ditches or creeks had guarding gates in 1929?\nIn \"The Funeral Pyre\" in Dr. <PERSON>'s Case-Book by <PERSON> \"1929\", <PERSON> found a dental plate of a dead man by a gate at the crossing of a ditch, and he wanted to know whether he come through this gate or was he only passing it.\n“We had better not make too many assumptions while we have so few facts,” said <PERSON>. He put down his case beside the gate, which guarded a bridge across a broad ditch, or drainage dyke, and opened his map.\n“The question is,” said he, “did he come through this gate or was he only passing it? This dyke, you see, opens into the creek about three-quarters of a mile farther down. The probability is, therefore, that if he came up from the river across the marshes he would be on this side of the ditch and would pass the gate. But we had better try both sides.", "321" ], [ "Let us leave our things by the gate and explore the ground for a few hundred yards, one on either side of the ditch. Which side will you take?”\nI elected to take the side nearer the creek, and, having put my camera down by the research-case, climbed over the padlocked gate and began to walk slowly along by the side of the ditch, scanning the ground for foot-prints showing the impression of boot-protectors. At first the surface was far from favourable for imprints of any kind, being, like that immediately around the gate, covered with thick turf. About a hundred and fifty yards down, however, I came upon a heap of worm-casts on which was plainly visible the print of a heel with a clear impression of a kidney-shaped protector such as I had seen in the hut. Thereupon I hailed <PERSON> and, having stuck my stick in the ground beside the heel-print, went back to meet him at the gate.\n“This is rather interesting, <PERSON>,” he remarked, when I had described my find. “The inference seems to be that he came from the creek—unless there is another gate farther down.\nWas it common that the bridges of ditches or creeks had guarding gates in 1929?\nI've searched for a photo that may show that, but I didn't find anything.", "495" ], [ "Here on the first page of Sir <PERSON>’s “The Golden Bough” is a descrption of a Goddess habitant on the shores of a lake in Northern Italy near La Riccia.\n“1.—The Arician Grove. Who does not know <PERSON>'s picture of the Golden Bough? The scene, suffused with the”golden glow of imagination in which the divine mind of <PERSON> steeped and transfigured even the fairest natural landscape, is a dream-like vision of the little woodland lake of Nemi, “Diana's Mirror,” as it was called by the ancients. No one who has seen that calm water, lapped in a green hollow of the Alban hills, can ever forget it. The two characteristic Italian villages which slumber on its banks, and the equally Italian palazzo whose terraced gardens descend steeply to the lake, hardly break the stillness and even the solitariness of the scene. <PERSON> herself might still linger by this lonely shore, still haunt these woodlands wild. In antiquity this sylvan landscape was the scene of a strange and recurring tragedy.", "464" ], [ "On the northern shore of the lake, right under the precipitous cliffs on which the modern village of Nemi is perched, stood the sacred grove and sanctuary of <PERSON>, or <PERSON> The lake and the grove were sometimes known as the lake and grove of Aricia.3 But the town of Aricia (the modern La Riccia) was situated about three miles off, at the foot of the Alban Mount, and separated by a steep descent from the lake, which lies in a small crater-like hollow on the mountain side. In this sacred grove there grew a certain tree round which at any time of the day and probably far into the night a strange figure might be seen to prowl. In his hand he carried a drawn sword, and he kept peering warily about him as if every instant he expected to be set upon by an enemy.4 He was a priest and a murderer; and the man for whom he looked was sooner or later to murder him and hold the priesthood in his stead. Such was the rule of the sanctuary. A candidate for the priesthood could only succeed to office by slaying the priest, and having slain him he held office till he was himself slain by a stronger or a craftier. This strange rule has no parallel in classical antiquity, and cannot be explained from it. ...”", "351" ], [ "This sounds a bit like <PERSON> short story \"The Dwindling Sphere,\" originally published in Astounding Science Fiction in March of 1940. The story was an early example of ecological science fiction. The technological conceit is that a small group of engineer/scientists have discovered a matter-transmutation process—somewhat like the replicator technology on Star Trek—with the property that the mass of the new object is always less that mass of the raw material used to produce it.\nIt is very puzzling, for the fact remains that the lump has been reduced to a fraction of its original weight and size. There is, after all, only one possible answer: the greater part of its mass must have been converted into energy. The question, then, is what became, of the energy?\nThe technology rapidly becomes a defining process of human civilization:\nActually, the discovery appears to have been an accident. <PERSON> took no interest in its development—regarded it as of little account.", "73" ], [ "Think of it! An invention more revolutionary than the discovery of fire, yet its inventor failed entirely to grasp its importance! To the end of his days it was to him merely a by‑product.\nThe story is told as a series of journal entries from descendants of the inventor of the matter-transformation process across the years and millennia. In the final entry, the size of the moon relative to the earth is mentioned:\nI have no doubt he will return later with some other fantastic delusion. On one occasion it was the legend that, instead of being twin planets, our earth and Luna were at one time of differing sizes, and that Luna revolved around the earth as some of the distant moons revolve around their primaries. This theory has been thoroughly discredited. It is true that there is a reduction of the earth's mass every time we scrape its surface to produce according to our needs; but it is incredible that the earth could ever have been several times the size of its companion planet, as these imaginative theorists would have us believe.\nAnd indeed there were resource wars over dirt:\nThe Eighty Years' War is over... Chief among the basic causes, of course, were the disputes, between adjoining districts over the right to extend their conversion pits beyond certain boundaries.\n\"The Dwindling Sphere\" has appeared in several anthologies, including Isaac Asimov Presents The Great SF Stories 2 (1940), edited by <PERSON>, 18 Greatest Science Fiction Stories edited by <PERSON>, and others.\nA good read, and I remember it frequently...", "489" ], [ "It's part of the story of \"The Devil with the Three Golden Hairs\" found in <PERSON>'s collection of folktales.\nYou can find a translation of it with the parallel German text here.\nThe basic synopsis is that the <PERSON> (<PERSON>-child) is prophesied to marry the king's daughter, to the latter's chagrin. The tries to get rid of the kid by having him go retrieve three golden hairs from the Devil's head. In doing so, he converses with three individuals who need help, including a ferryman who is forced to row and can never be free. Once he gets to Hell...\n...the Devil was not at home, but his grandmother was sitting in a large arm-chair. \"What do you want?\" said she to him, but she did not look so very wicked. \"I should like to have three golden hairs from the devil's head,\" answered he, \"else I cannot keep my wife.\"\nShe decides to help him out.", "351" ], [ "While the Devil was sleeping, she plucked a hair out and told him one of her dreams. (On Wikipedia it says the Devil had the dreams, but the English and German I provided agree it's the grandmother's dreams.) In one of the dreams, she says an ferryman cannot be freed, and the Devil replies:\n\"What was the dream, then?\" asked he [=the devil], and was quite curious. \"I dreamt of a ferry-man who complained that he must always ferry from one side to the other, and was never released. What is the cause of it?\" - \"Ah! the fool,\" answered the devil; \"when any one comes and wants to go across he must put the oar in his hand, and the other man will have to ferry and he will be free.\"\nThe story ends with the <PERSON> telling this to the ferryman and then tricking the king into taking the oars:\nThe greedy King set out in all haste, and when he came to the river he beckoned to the ferry-man to put him across. The ferry-man came and bade him get in, and when they got to the other shore he put the oar in his hand and sprang out. But from this time forth the King had to ferry, as a punishment for his sins. Perhaps he is ferrying still? If he is, it is because no one has taken the oar from him.", "54" ], [ "The hung <PERSON> and the crucified <PERSON>\nThe god who dies but resurrects, is an often-re-appearing legend in many religions. Amongst the deities that die and then come back to life are: Horus, <PERSON>, <PERSON> and <PERSON>. <PERSON> and <PERSON> are also, for sure, crucified. Apart from the sacrificial death itself, there also is a thorough description that <PERSON>, <PERSON> and <PERSON> have been born the 25th of December. All of them also have twelve disciples and they create miracles. On a shrine dedicated to <PERSON> it is written “You have saved us through your shed blood”. This shrine is nowadays situated beneath the Sancta Prisca church in Rome.\nParts of these mythological stories also fit quite well to the Germanic god <PERSON>, or Wotan.\nMidwinter Blót was held to honor <PERSON> around the time of Winter Solstice, which in the old days occurred on December 25th. <PERSON> has twelve lower ranked gods under him, and one of them (<PERSON>) is a traitor. <PERSON> is hung upon the tree of Yggdrasil for three days, according to <PERSON>. After his death, <PERSON> gets more power than before it. In the Christian tradition, <PERSON> has increased his powers after he died and resurrected after three days. Crucifixion, which was a common way to execute slaves, thieves and traitors in the ancient Mediterranean world, has not been practiced in the Germanic territories, and hanging has instead been seen as a dishonoring way to die. Executions with guillotine or sword have been seen as a more honoring way to die rather than hanging, all the way into our modern times. Both <PERSON> and <PERSON> get stabbed with spears during their sacrificial deaths. <PERSON> was hung upon a tree, and <PERSON> was hung upon a cross made out of wood.", "351" ], [ "According to some Christian beliefs, that cross was made out of a tree that <PERSON>, the first man, had planted. <PERSON>, but also several other Egyptian gods, are depicted holding a hieroglyph known as “the Ankh”. That symbol is very similar to the cross that the Christians are using, and both symbols mean life and resurrection.\n<PERSON> was not born of a virgin, since the <PERSON> are mentioning that he had both a father and a mother, <PERSON> and Bestla. It can though be said that <PERSON>, the father of <PERSON> was born when he got licked out of a block of ice by the cow Audhumbla.\nExperts in religion have mentioned that <PERSON> is similar to the god Mithra, the main savior deity of the late ancient world, who also has twelve disciples, all of whom are represented by the twelve signs of the Zodiac. But it looks like the idea of the god that dies and resurrects is around 5000 years old, if you go all the way back to the myth of <PERSON>. <PERSON>’s most ecstatic aspect is pretty similar to the description of the Greek god <PERSON>. Both Mithra and <PERSON> were celebrated at the Spring Equinox, and the Christians celebrate Easter at spring as well.\nIn other words, it is more than likely that the Christians took over an elder myth and blended it into their own belief system. The Jews were strongly influenced by the Egyptians, and monotheism was grounded in Egypt. The first Christians were most likely Jews who were inspired by the pagan world’s ideas about salvation, and thus added those ideas into their own belief system. The pagan teachings about salvation did not claim to be the only way to salvation, and thus accepted other religions. The idea that everyone must think in the same way and fight for the same belief system, did not exist amongst the polytheistic religions.\nBoth <PERSON> and <PERSON> were celebrated with mystery plays, and also in partially secret societies. It is thus believable that the first Christians believed in a mythological savior that was born, lived, created miracles and then got executed, just to resurrect and come back to\nEarth. Later on, when Christianity increased in popularity, some of the Christians started to believe that their savior was a real, physical being, that lived and acted in a recent past. The Christians started to think that the “physical” savior lived and died in the 30-s of our time. Since the Christians converted as many as possible to Christianity, their converts literally believed everything that was taught to them. The monotheistic religions are struggling even nowadays with their so called literalism.\nhttp://ideellkulturkamp.", "72" ] ]

[ 4528, 3595, 1798, 5745, 6272, 7423, 9829, 6978, 7152, 9129, 11408, 4865, 4963, 1839, 9841, 708, 10882, 628, 4824, 6302, 1116, 8328, 3746, 5301, 9314, 2775, 2999, 2817, 4063, 8953, 2232, 7576, 10168, 5266, 10680, 1338, 11298, 1550, 9229, 2236, 4512, 534, 8946, 3014, 1573, 3211, 2818, 3946, 6857, 7989, 8562, 10459, 536, 1808, 3483, 9900, 10076, 6398, 9341, 3115, 7313, 6845, 1294, 4966, 10328, 10526, 784, 9884, 11070, 6361 ]

[ [ "I’m assuming that by cross-terms you mean off diagonal terms.\nFirst, when talking about off-diagonal terms we clearly mean in a fixed basis. For example, in an eigenbasis of $\\rho$ your state has no off-diagonal elements whatsoever.\nSecond, what you say about measuring clearly holds when performing measurements in that basis ($|0\\rangle, |1\\rangle$ in your basis). Or more precisely when we measure an observable that has the same eigenbasis.\nComing to the physical meaning of these off-diagonal terms, they are also called ‘coherences’. They are responsible for the interference effects of a quantum particle. In particular those effects that make them sometime look like waves. The prototypical experiment that reveal quantum coherence is the double slit experiment.\nThe following thought experiment has been put forward by <PERSON> et al. (see [1]) to describe the essence of the quantum coherence and the double slit experiment.\nImagine to prepare the following state\n$$ |\\Psi\\rangle = ( |\\phi\\rangle_L + e^{i \\theta} |\\phi\\rangle_R)/\\sqrt{2} $$\nWhere $|\\phi\\rangle_{L,R}$ are Gaussian wavepackets centered around $L, R$ (left, right) with spread much smaller than their separation. This requirement assures that the two states are essentially orthogonal.", "976" ], [ "The left (right) wave packet is prepared with momentum $p$ ($-p$) such that it travels to the right (left). If you measure the position at $t=0$, you will find two Gaussian blobs around $L$ and $R$ and the phase $\\theta$ is not observable. From this experiment alone the state cannot be distinguished from a classical state.\nNow let evolve the state until the time where the wavepackets collide. At this point it turns out that if you measure position the phase $\\theta$ becomes observable! It’s as if the particle interfered with itself, pretty much like a wave.\nIf you repeat the experiment many times with different phases $\\theta$, and every time you measure the position of the particle (for example, the particle hits a screen), you will indeed see a figure of interference forming on the screen.\nAdded 19/9/22\nMathematical Details\nWe work in a setting where there is a free particle (not subject to any potential) moving on the real line. Hence the Hamiltonian is $H=a p^2$ ($a=1/(2m)$). If you want to be pedantic the Hilbert space is $\\mathcal{H} = L^2(\\mathbb{R})$.\nFirst consider as initial state a Gaussian wavepacket centered around $x_0$ moving with momentum $p_0$:\n$$ \\psi(x)=\\frac{e^{-\\frac{(x-x_{0})^{2}}{4\\sigma^{2}}}}{(2\\pi\\sigma^{2})^{1/4}}e^{ip_{0}x}. $$\nCorrectly $|\\psi(x)|^2$ is a Gaussian centered around $x_0$ with standard deviation $\\sigma$.\nThe probability distribution of position at time $t$ is\n\\begin{align} \\left|\\psi(x,t)\\right|^{2} &=\\frac{e^{-\\frac{(x-x_{t})^{2}}{2\\sigma_{t}^{2}}}}{\\sqrt{2\\pi\\sigma_{t}^{2}}} \\ x_{t} &=x_{0}+2p_{0} a t \\ \\sigma_{t} &=\\sqrt{\\sigma^{2}+\\frac{a^{2}t^{2}}{\\sigma^{2}}}. \\end{align}\nThis means that if $p_{0}>0$ ($p_{0}<0$) the wavepacket travels to the right (left). Moreover the wavepacket spread a bit in time according to $\\sigma_t$.\nNow initialize the system in the following superposition.", "795" ], [ "There are several different notions of microstates or distinguishability that might be relevant to your question.\nCoarse-graining of phase space into Planck cells.\nConsider two classical variables $x$ and $p$ with $x \\sim x+x_0$ and $p \\sim p+p_0$. You can think of this system as describing a particle that lives on a circle of radius $x_0$ and where momentum is also defined only up to multiples of $p_0$. A physical realization of this situation is provided by a particle moving on a discrete lattice with periodic boundary conditions.\nWe can write the classical Lagrangian in the suggestive form $L = \\dot{x} p - H$ which means that $p$ is conjugate to $x$. The volume of phase space is finite and given by $x_0 p_0$. Dividing phase space into <PERSON> cells of volume $h$ gives us $N = x_0 p_0 / h$ states. This is the semiclassical estimate.\nNow we turn to the full quantum theory. Consider the operators $X = e^{i 2\\pi x/x_0} $ and $P = e^{i 2\\pi p/p_0}$. These operators satisfy $PX = XP e^{i 4\\pi^2 \\hbar/(x_0 p_0)} = XP e^{ 2\\pi i /N}$. Starting with a state $|0\\rangle$ satisfying $P|0\\rangle = |0\\rangle$ we can create new states by acting with $X$. The state $X^n |0\\rangle$ satisfies $P X^n |0\\rangle = e^{ 2 \\pi i n/N} X^n |0\\rangle$, so the state $X^N |0\\rangle$ is proportional to $|0\\rangle$.", "976" ], [ "Thus we have constructed precisely $N$ states of the form ${|0\\rangle, X|0\\rangle, ..., X^{N-1} |0\\rangle }$ using the exact quantum operator algebra. What we have shown is that the semiclassical estimate gives the correct full quantum state count in this example.\nOne answer to your original question is then that a two level system can be understand as two Planck cells of phase space.\nCounting partially orthogonal quantum states.\nOf course, there are an infinite number of quantum states as parameterized by the Bloch sphere - each point is slightly different. However, most of these states are not orthogonal. We can ask how many different choices of parameters give states that are $\\epsilon$-orthogonal e.g the size of the largest set ${|\\psi_i \\rangle }$ with $|\\langle \\psi_i | \\psi_j \\rangle| \\leq \\epsilon$ for $i \\neq j$. Obviously for $\\epsilon \\rightarrow 0$ we get something like the dimension of the Hilbert space. For example, the one parameter family of states $|\\theta\\rangle = \\cos{\\theta} |0 \\rangle + \\sin{\\theta}|1\\rangle$ satisfies $\\langle \\theta | \\theta'\\rangle = \\cos{(\\theta-\\theta')}$. If $\\epsilon = 0$ then we can only choose $\\theta=0,\\pi/2$. On the other hand, if $\\epsilon = 1- \\delta$ then we have $\\cos{(\\Delta \\theta)} < 1 - \\delta$ ($\\Delta \\theta$ is the spacing between neighboring $\\epsilon$-orthogonal states) or $\\Delta \\theta > \\sqrt{2 \\delta}$ ($\\Delta \\theta$ assumed small). This implies that we have roughly $2\\pi/ \\Delta \\theta$ $\\epsilon$-orthogonal states. You can see that as we permit more and more nearly parallel states, the number of $\\epsilon$-orthogonal states increases.\nA general estimate for the number $\\epsilon$-orthogonal states in a $D$ dimensional Hilbert space is $(1-\\epsilon)^{-D/2}$ for $1-\\epsilon$ small. Roughly speaking, we're covering up the $D$ dimensional space with little spherical chuncks of radius $\\sqrt{1-\\epsilon}$ and volume $(1-\\epsilon)^{D/2}$.", "976" ], [ "My approach would be: first determine the time evolution of $\\hat{x}(t)$ and $\\hat{p}(t)$. For $\\hat{x}$ you have $$ \\frac{d}{dt}\\hat{x}_H(t) = i[H_H,\\hat{x}_H(t)] = \\frac{i}{2m} [\\hat{p}_H(t)^2,\\hat{x}_H(t)] = \\frac{\\hat{p_H(t)}}{m} $$ and for $p$ you have (assuming $0\\leq t \\leq T$) $$ \\frac{d}{dt}\\hat{p}_H(t) = i[H_H(t),\\hat{p}_H(t)] = -m\\omega_0^2 \\hat{x}_H(t) + F_0\\sin(\\Omega t) $$ These are coupled differential equations, which you can decouple by differentiating them once more with respect to time and performing a substitution. For instance,\n$$ \\frac{d^2}{dt^2} \\hat{x}_H(t) = \\frac{1}{m} \\frac{d}{dt} \\hat{p}_H = -\\omega_0^2 \\hat{x}_H(t)+\\frac{F_0}{m}\\sin(\\Omega t) $$ where I substituted $\\frac{d}{dt} \\hat{p}_H(t)$ by its equation of motion found earlier. You can also get an equation like this for $\\hat{p}_H(t)(t)$, which I leave for you..\nNow, these equations can be solved using your favorite method, provided you give them suitable boundary conditions.", "526" ], [ "Note that you only need one boundary condition for $x$ and $p$ (which is $x_H(0)=\\hat{x}_S$ and $p_H(0)=\\hat{p}_S$ It will give you some expression for $\\hat{x}_H(t)$ and $\\hat{p}_H(t)$ in terms of $\\hat{x}_S$ and $\\hat{p}_S$. The Heisenberg Hamiltonian is then easily determined by substituting $\\hat{x}_H(t)$ and $\\hat{p}_H(t)$.\nWith that expression in hand you should be able to find $\\langle H(t)\\rangle$ (note that you should consider the cases where $t<0$ and $t>T$ separately).\nEDIT: The proof regarding my statement below: In the <PERSON> picture the Hamiltonian is\n$$\\hat H_S=\\frac{\\hat{p}_S^2}{2m}+\\frac{1}{2}m\\omega_0^2\\hat{x}_S^2-\\hat{x}_SF_0\\sin(\\Omega t)$$\nand the <PERSON> picture is given by $H_H = U^\\dagger(t) H_S U(t)$. So if you take for instance the first term you get:\n$$U^\\dagger(t) \\frac{\\hat{p}_S^2}{2m}U(t) =\\frac{1}{2m} (U^\\dagger(t) \\hat{p}_S U^\\dagger(t))(U(t)\\hat{p}_SU(t)) =\\frac{1}{2m} \\hat{p}_H(t)^2 $$\nYou can do the same for the other terms. In the end you just effectively replace $p_S\\rightarrow p_H(t)$ and the same for $x$.", "526" ], [ "I believe that it is true as long as there does not exist a non-trivial unitary operator $U$ that commutes with the Hamiltonian ($[H,U] = 0$) in the subspace of ground states. If such an operator exists then for a ground state $|\\phi_0\\rangle$ with energy $E_0$ we have $$HU|\\phi_0\\rangle = UH|\\phi_0\\rangle = E_0\\left(U|\\phi_0\\rangle\\right)$$ and so $U|\\phi_0\\rangle$ also has the lowest possible energy $E_0$ and it thus also a ground state. Note that the statement of non-triviality of $U$ is important. It needs to be non-trivial in the subspace of ground states, that is $U|\\phi_0\\rangle \\neq e^{i\\theta}|\\phi_0\\rangle$ for any phase $\\theta$, otherwise there is no degeneracy.", "66" ], [ "(Unitarity is needed so that $U|\\phi_0\\rangle$ is a state with norm 1)\nMore succinctly, if there exists a unitary operator $U$ such that $[H,U]=0$ and $U|\\phi_0\\rangle\\neq e^{i\\theta}|\\phi_0\\rangle$ for any phase $\\theta$ then we have ground state degeneracy.\nIn the example you have given we see that the matrix elements in the basis given ${|a\\rangle,|b\\rangle,|c\\rangle}$ is $$H = \\begin{pmatrix}1&0&0\\0&1&0\\0&0&2\\end{pmatrix}$$ from which we see there exists a unitary operator, with matrix elements $$U = \\begin{pmatrix}0&1&0\\1&0&0\\0&0&1\\end{pmatrix}$$ which commutes with $H$ and is non-trivial in the ground-state space.\nProof that non-existence of $U$ implies non-degenerate ground state:\nAssume $\\nexists U$ s.t. ${[H,U]=0 ~~\\mbox{and}~~ U|\\phi_0\\rangle \\neq e^{i\\theta}|\\phi_0\\rangle}$\nNow, for every state $|a\\rangle$ and $|b\\rangle$, $\\exists U_{ab}$ which is unitary that takes us from $|a\\rangle\\rightarrow|b\\rangle$. We are interested in the operator that take us from $|\\phi_0\\rangle$ to any $|a\\rangle$ in our Hilbert space (which obviously includes all possible ground states), which we denote by $U_{a0}$. This means that any state $|a\\rangle$ can be written as $|a\\rangle = U_{a0}|\\phi_0\\rangle$. By our starting assumption $U_{a0}$ either satisfies $$(1)~~~~~~ [H,U_{a0}]\\neq 0,~~~~~~~~\\mbox{or}~~~~~~~~(2)~~~~~U_{a0}|\\phi_0\\rangle = e^{i\\theta}|\\phi_0\\rangle$$ If (1), then we have $$H|a\\rangle = H U_{a0}|\\phi_0\\rangle \\neq U_{a0}H|\\phi_0\\rangle = E_0|a\\rangle~~~\\implies~~~H|a\\rangle \\neq E_0|a\\rangle$$ and so $|a\\rangle \\neq |\\phi_0\\rangle$ is not a ground state.\nIf (2), then $|a\\rangle = e^{i\\theta}|\\phi_0\\rangle$ and so $|a\\rangle$ and $|\\phi_0\\rangle$ represent the same state.\nThus the non-existence of $U$ implies the non-existence of a second ground state and thus non-degeneracy.", "680" ], [ "Thanks for your hints so far. The question was to some extend already discussed here: (https://physics.stackexchange.com/questions/109343/eigenstate-of-field-operator-in-qft). <PERSON>, I give a more verbose and down-to-earth answer to my question. There is also a remark why I was confused first...\nEigenstates of the annihilation field as classical states\nWe assume a real valued scalar quantum field $A(x)$ of the form (neglecting normalization)\n\\begin{equation} \\hat A(x) = \\int \\hat a^{*}(k)e^{ikx} \\, d^{3} k + \\int \\hat a(k)e^{-ikx} \\, d^{3} k = \\hat A_c(x) + \\hat A_a(x) \\end{equation}\nwhich is split in a creation and annihilation part.", "669" ], [ "We are looking for a eigenstate $| \\psi \\rangle$ of the annihilation operator $\\hat A_a(x)$. Such a state is the tensor product of single mode coherent states: $| \\psi \\rangle = \\otimes_k |\\alpha(k) \\rangle_k$, since every single mode state in the tensor product is an eigenstate of the corresponding annihilation operator $a(k)$ with eigenvalue $\\alpha(k)$. Hence $\\hat A_a(x) | \\psi \\rangle = \\int d^{3} k' e^{-ik'x} \\hat a(k')\\otimes_k |\\alpha(k) \\rangle_k =\\int d^{3} k' e^{-ik'x} \\alpha(k') \\otimes_k|\\alpha(k) \\rangle_k = \\psi(x) | \\psi \\rangle$\nwith the eigenvalue $\\psi(x) = \\int d^{3} k e^{-ikx} \\alpha(k)$. The eigenstate $| \\psi \\rangle$ is also called coherent and can be written as \\begin{equation} | \\psi \\rangle = \\otimes_k e^{\\alpha(k) \\hat a^{}(k)} |0 \\rangle = e^{\\int d^{3}k \\alpha(k) \\hat a^{}(k) } |0 \\rangle = e^{\\int d^{3}x \\hat A_c(x) \\psi(x)} |0 \\rangle = e^{\\int d^{3}x \\hat A(x) \\psi(x)} |0 \\rangle \\end{equation} The first part of the above equation is more or less by definition true (refer to single mode coherent states) the second part is valid since all $\\hat a^{*}(k)$ commute, the third part is valid since (Fourier expansion of field and eigenvalue)\n\\begin{equation} \\int d^{3}x \\hat A_c(x) \\psi(x) = \\int \\int d^{3} k d^{3} q \\, \\int e^{i(k - q)x} d^{3}x \\, \\alpha(q) \\hat a^{} (k) = \\int d^{3} k \\alpha(k) \\hat a^{}(k) \\end{equation}\n(The space integral results in a delta function $\\delta(k-q)$). The last part of the defining equation above is true since $\\hat A_a |0 \\rangle = 0$ and hence $e^{\\int d^{3}x \\hat A_a(x) \\psi(x)} |0 \\rangle = 0$.\nCorollary: $\\langle \\psi |\\hat A_a(x) |\\psi \\rangle = \\langle \\psi |\\psi(x)|\\psi \\rangle = \\psi(x) \\langle \\psi |\\psi \\rangle = \\psi(x)$.", "66" ], [ "My feeling is that you are confused by notation.\nI read that when I have two identical particles with spin 1/2 there are 4 possibilities\nThese are not four possibilities, but these are four basis states. They form a complete orthonormal set of states for two spins. These basis states span the Hilbert space of all possible two-spin states.\nThe notation, for example $\\left|\\left.\\uparrow\\downarrow\\right>\\right.$, is a shorthand for $$ \\left|\\left.\\uparrow\\downarrow\\right>\\right. \\equiv \\left|\\left.\\uparrow\\right>\\right._1\\otimes\\left|\\left.\\downarrow\\right>\\right._2,$$ meaning that particle 1 is in state $\\left|\\left.\\uparrow \\right>\\right.$ and particle 2 is in state $\\left|\\left.\\downarrow\\right>\\right.$ (note, there is a logical and).\nwhat's the difference between these 2 states $$ \\left|\\left.\\uparrow\\downarrow\\right>\\right., \\left|\\left.\\downarrow\\uparrow\\right>\\right.$$\nGiven the above, you can now tell the difference: in the first case, particle 1 is in state $\\left|\\left.\\uparrow\\right>\\right.$ and particle 2 is in state $\\left|\\left.\\downarrow\\right>\\right.$, while in the second case particle 1 is in state $\\left|\\left.\\downarrow\\right>\\right.$ and particle 2 is in state $\\left|\\left.\\uparrow\\right>\\right.$.\nSo far, we made no use of the indistinguishability of the two particles, we even labeled them as particle 1 and particle 2, so we treated them as distinguishable particles.\nThen since there is the symmetrization requirement I can take as eigenvalues the following 4 states: $$ \\left|\\left.\\uparrow\\uparrow\\right>\\right., \\left|\\left.\\downarrow\\downarrow\\right>\\right.,\\frac{1}{\\sqrt{2}}\\left(\\left|\\left.\\uparrow\\downarrow\\right>\\right.+\\left|\\left.\\downarrow\\uparrow\\right>\\right.\\right), \\frac{1}{\\sqrt{2}}\\left(\\left|\\left.\\uparrow\\downarrow\\right>\\right.-\\left|\\left.\\downarrow\\uparrow\\right>\\right.\\right).$$\nNote first that I have put factors of $1/\\sqrt{2}$ instead of your factors $1/2$. This is, because we want the states to remain normalized. Second, please be aware that these four states are in no way eigenvalues in this context, they are also not eigenstates, because you did not specify any hamiltonian, of which these states could be the eigenstates.", "66" ], [ "These four new states simply form an alternative complete and orthonormal set of basis states for two spins.\nNow let me try to explain, why these four states are well suited to describe indistinguishable particles. To have indistinguishable particles should mean that it should not matter in our description of the two particles, which of them is in which state. In other words, when we exchange the labels 'particle 1' and 'particle 2', we should get the same observable properties of the system. This is indeed the case for our four new basis states. If you remember our notation convention from above, then, for example, $$ \\left|\\left.\\psi\\right>\\right. = \\frac{1}{\\sqrt{2}}\\left(\\left|\\left.\\uparrow\\downarrow\\right>\\right.-\\left|\\left.\\downarrow\\uparrow\\right>\\right.\\right) = \\frac{1}{\\sqrt{2}}\\left(\\left|\\left.\\uparrow\\right>\\right._1\\otimes\\left|\\left.\\downarrow\\right>\\right._2-\\left|\\left.\\downarrow\\right>\\right._1\\otimes\\left|\\left.\\uparrow\\right>\\right._2 \\right).$$ Now exchanging the labels for particle 1 and 2, we have $$ \\frac{1}{\\sqrt{2}}\\left(\\left|\\left.\\uparrow\\right>\\right._2\\otimes\\left|\\left.\\downarrow\\right>\\right._1-\\left|\\left.\\downarrow\\right>\\right.", "66" ], [ "Relation between Clebsch-Gordan Coefficients and Wigner $D$-Matrix\nIt is known that Clebsch-Gordan coefficients are those of a linear transformation from the product basis ${|j_1,j_2;m_1,m_2\\rangle}{m_1\\in {-j_1,...,j_1},m_2\\in {-j_2,...,j_2}}$ to the coupled basis ${|j_1,j_2;J,M\\rangle\\rangle}{J\\in {|j_1-j_2|,...,j_1+j_2},M\\in {-J,...,J}}$ (the double ket to distinguish between the two basis). These two basis are orthonormal basis in the space $\\mathscr{E}(j_1)\\otimes\\mathscr{E}(j_2)$ and that means that there is a unitatry operator $\\hat U$ that transforms one basis to the other. The matrix elements of this operator are by construction the CG-Coefficients.\nOn the other hand a physical rotation $R$ is implemented on a ket in $\\mathscr{E}(j_1)\\otimes\\mathscr{E}(j_2)$ by a unitary operator $\\mathscr D (R)$.\nQuestion:\nIs there a physical rotation $R$ such that $\\mathscr D (R) = \\hat U$, where $\\hat U$ is the change-of-basis operator $\\hat U: {|j_1,j_2;m_1,m_2\\rangle} \\mapsto {|j_1,j_2;J,M\\rangle\\rangle}$ ?\nMy answer is no and here are my two arguments\n1.", "956" ], [ "Diagonalisation of observables (namely $\\mathbf J^2$ & $J_z$) is not possible by physical rotations\n2. The map $\\mathscr D :SO(3) \\to SU((2j_1+1)(2j_2+1))$ may not be surjective, i.e. there are unitary operators $\\hat{ \\mathcal O} \\in SU((2j_1+1)(2j_2+1))$ which do not correspond to physical rotations $R \\in SO(3)$\nThese two arguments do not exclude each other but I hope that someone can make this mathematically more precise, I hope this question makes sense.\nAdded:\nin other words are there e.g. Euler angles $\\alpha, \\beta,\\gamma$ such that matrix elements are something like this $$ \\mathscr D^{(J)}_{M',M}(\\alpha, \\beta,\\gamma) = \\langle j_1,j_2;m_1,m_2|j_1,j_2;J,M\\rangle $$ I know the indices are not consistent, they do not make sense! but this may not be a reason to beleive that there is no $R(\\alpha, \\beta,\\gamma)$ whose representation $\\mathscr D(R)$ does as\n$$\\hat U: {|j_1,j_2;m_1,m_2\\rangle} \\mapsto {|j_1,j_2;J,M\\rangle\\rangle}$$", "956" ], [ "Discrete eigenvalues can always be labeled by the integers, so we can always pick up $E_n$ with $n$ starting from $0$ or $1$, it is just a matter of convenction. I suppose this is where your question originates. For the harmonic oscillator the energies are given by $\\hbar \\omega (m +1/2)$ with $m=0,1,\\ldots$ so it is natural to pick $n=m$ starting from $0$.\nFor the particle in the box, note that the problem is equivalent to a \"free\" particle with certain boundary conditions (wavefunction zero at the border). In this sense it is no surprise that \"momentum\" is conserved (people speak of quasi-momentum in this case). In this picture the Hamiltonian is simply\n$$H = \\frac{p^2}{2m}.$$\nIf you set the box as in $[0,L]$ you can write the eigenfunctions as\n$$\\psi_k(x) \\propto \\sin(kx)$$\nwhere $k$ is this quasi-momentum to be determined. In this way one of the boundary conditions is automatically satisfied. To satisfy the other one we must impose $\\sin(Lk)=0$ which in principle leads to $k= m\\pi/L$, with $m\\in \\mathbb{Z}$. However, $k$ and $-k$ single out the same quantum state (a quantum state is an equivalence class of vectors which differ by a phase).", "976" ], [ "Moreover $k=0$ is not allowed because the zero wave-function is not normalizable. Hence we are led to\n$$k= \\frac{n\\pi}{L}, \\ \\ n = 1,2,\\ldots$$\nIn a sense, physically, this tells us that the state with zero momentum (a state that does not move left or right) is not allowed. This is clearly a quantum mechanical effect (a fixed particle is perfectly allowed classically). You can think of its origin in the <PERSON>'s uncertainty principle. Since $H\\propto p^2$ we can obviously label the energies with the same label that we use for the momentum (another good notation would be simply to label them with the quasi-momentum itself as in $E_k$ and remember what is the spectrum of $p$, $\\sigma(p)$.\nI suppose you knew all of this but I don't think you can say much more.\nEdit\nLet me briefly comment on the number of nodes of the wavefunctions.\nFor a Hamiltonian of the form\n$$ H= \\frac{p^2}{2m} + V(x) = - \\frac{\\hbar^2}{2m} \\frac{\\partial^2}{\\partial^2 x} +V(x) $$\na theorem by <PERSON> and <PERSON> (generally called nodal theorem) states that the ground state wave function has no nodes (can be chosen to be everywhere non-negative) and the $n$-th level has precisely $n-1$ nodes. Moreover if the potential goes to infinity as $|x| \\to \\infty$, then the eigenvalues form a discrete unbounded sequence. I imagine variations of this theorem exist for $\\mathbb{R}^d$. So the behavior you observed for the number of nodes is in fact quite general.", "976" ] ]

[ 10100, 10375, 10996, 4534, 3311, 8032, 8758, 1709, 4875, 689, 934, 4908, 6957, 5333, 9356, 10261, 9504, 5359, 9209, 5478, 11030, 257, 2725, 3745, 9473, 1113, 3579, 4220, 3315, 9172, 2097, 5947, 4652, 721, 2445, 6148, 6414, 10682, 2092, 2768, 3556, 8045, 343, 2731, 10749, 2745, 1222, 189, 6749, 2607, 2462, 6763, 3768, 3636, 8497, 10692, 3435, 932, 2040, 5237, 1647, 7300, 1540, 10085, 6889, 6813, 2474, 8221, 2323, 7871 ]

[ [ "Short answer is it can't form when the temperature of the water is above the freezing point. As <PERSON> and @tpg2114 have pointed out the temperature of water on surfaces will frequently be lower than the air temperature.\nI'm answering just to clarify that the wet-bulb temperature is only indirectly relevant. The wet bulb temperature is not (definitionally) the lowest temperature an object can reach as a result of evaporation. It does provide a lower bound on the temperature that can be reached under outside conditions as experimentally at these pressures it turns out that the rate of convective heating of the water by the air tends to be faster than the rate of evaporative cooling of the water.", "108" ], [ "Thus, the coldest evaporative cooling can reduce the water will be no lower than the coldest the water can make the air. This, of course, occurs when the air evaporates as much water as possible and the total amount of air is very large compared with the water left (so the water contains a negligible amount of thermal energy and is cooled to the air temperature) and at a temperature equal to the wet bulb temperature.\nWorking outside one also has to deal with radiative and convective transfers from a very very large volume of air and if still air is left around the water reservoir the rate of cooling by evaporation will drop as the air approaches saturation and the huge body of dry air will start to heat the reservoir faster than it is being cooled. Experimentally, it turns out that high wind speeds and shielded reservoirs give the largest cooling but can't actually reach the wet bulb temperature.\nHowever, as suggested here at lower air pressures convection does not ultimate dominate evaporative cooling. In this case one can reduce the water to a lower temperature than the surrounding air and the wet bulb temperature is no longer a minimum value for the temperature evaporation can reduce surface to. Essentially this works since you are letting the highest energy molecules in the water escape and thereby reducing the average kinetic energy of the remaining molecules and the air is so thin that this effect cools the water faster than the neighboring air can heat it back up.", "108" ], [ "This is not a simple problem to solve for mathematically. To do so you would need to know the temperature and velocity of the air coming out of the AC unit, as well as the velocity of air outside as well as which windows are open and at what angle outside air is hitting the windows. Basically, you would need to figure out how well the AC air mixes with the room air as well as the the general paths the air currents follow.\nAs others have mentioned, humidity is also a concern. If you are bringing in humidity from the outside the AC will have to work harder to remove it.\nFor example, if the air from the A/C follows a laminar flow and does not mix well with the air in the room right away, a large part of it could goes out the window without having reduced air temperature.", "108" ], [ "The larger the temperature differential between the AC air and the room air, and the lower the amount of mixing occurs, the less efficient it is going to be.\nMost likely it would be easier to just perform some experiments, trying to control for a single variable at a time.\nHowever, having said that, assuming sufficient mixing of the air what you are going to see in practice is that opening the window causes the temperature to cool faster, because you have two sources of air colder than the room. You could set up an equation using two idealized heat transfers to try to approximate it. But if the temperature differential is only 4C you may find it doesn't really cool that much faster, and things like wind gusts and humidity may make it a wash. In my experience, latent heat from the structure itself makes it very difficult to bring room temperature that close to outside air temperature (for instance, in a brick/stone wall type building I have found it difficult to cool an interior to closer than 5C above outdoor temperature over the course of a night).\nHowever, in any case using both the AC and opening the windows will obviously use more electricity than just opening the windows.", "108" ], [ "It's correct to say that the temperature of the air in the jet coming from the neck of the bottle will be less than the temperature of the air in the bottle. The temperature of the air in the bottle will also be a little higher than the temperature of the outside air. The question is, will both the temperature and relative humidity of the jet air be sufficiently low to result in a net \"comfort zone\" in the room.\nThe \"comfort zone\" is a region of ambient air temperature and relative humidity that induces a comfortable feeling, and it has been mapped out by ASHRAE (American Society of Heating Refrigeration and Air Conditioning Engineers). Such data can be found for instance at https://www.dartmouth.edu/~cushman/courses/engs44/comfort.pdf\nI assume this device is meant only for Summer months, when outdoor humidity and temperatures are very uncomfortable. In order to work then, the device must deliver air to the room that will result in the temperature and humidity space according to the ASHRAE standard.\nIt's clear that the temperature of the jet air exiting the bottles will be a little lower than the temperature of the air in the bottle. That's simply because the expansion process through the nozzle is roughly isentropic. It's very likely that, for normal outside atmospheric conditions, the air pressure in the bottle will exceed room pressure only slightly. That's because the pressure in the bottle can be greater than the air pressure in the room only when outside wind collides with the bottles. Such a collision converts the kinetic energy of the wind velocity to a stagnation pressure. For normal wind speeds, however, this increase in pressure is small.\nThe velocity of the air jet into the room will thus be small, and the net temperature difference between outside air and air jet velocity will be small. Considering also that when the air jet mixes with room air, it's kinetic energy is dissipated, being converted to heat.", "108" ], [ "The net effect is that the final temperature of the jet air after it mixes with room air will be slightly elevated above its temperature when it exits the bottle. The conclusion here is that there can be only a minimal sensible cooling effect from this device. Most importantly, sensible cooling is only part of the air conditioning process, and the real question is what's the story with relative humidity.\nOften the most important process of air conditioning is the removal of water vapor from the air. The ASHRAE graphs show that the relative humidity necessary for comfort is often much less than the relative humidity present in Summer outside air. What happens to the water vapor (absolute humidity) of the air that's pushed through these bottles? Unfortunately nothing much.\nIn the vast majority of air conditioning processes, water vapor must be removed from the outside air before it can become comfortable for humans. Water removal is usually the most intensive process in air condition, not the reduction in (sensible) temperature. This device offers little mechanism for the removal of water vapor. The very slight increase in bottle pressure and the relatively low pressure drop encountered by the air in moving through the bottles ensures that the water vapor in the outside air remains in the air pushed into the room. If the jet air temperature would be lowered to a value below the dew point of the outside air, condensation would remove some of this water vapor. It's very unlikely that such a device could accomplish such low temperatures, for the reasons already explained. The net result is that this device pushes more water vapor into the room - not a very good means for conditioning outside air for comfort.\nBottom line is that for much of the typical Summer months in areas that require air conditioning, this device will not be able to produce a comfort zone, as defined by ASHRAE standards.", "108" ], [ "In general, heat transfer with internal flows - like flows in a pipe - does depend on Reynolds Number. For small enough Reynolds number, the flow is laminar and the nature of the laminar flow is such that fluid inertia has negligible influence, resulting in a constant value for the laminar Nusselt number, but only when the internal flow is \"fully developed.\" For laminar flow in the entrance region of the pipe, the Nusselt number is not constant, and its value is different for different heat transfer configurations. This is explained more fully below.\nThe Reynolds number is a ratio of inertial forces to viscous forces, VD/Nu, where V is fluid velocity, D pipe diameter, and Nu fluid kinematic viscosity. When inertial forces are small enough, viscosity dominates, and the transfer of momentum across minute streamlines is solely because of friction (viscosity), and it occurs on a molecular level. At that level, the momentum is \"diffused\" across the streamlines, being transferred by molecule bumping into molecule. With larger Reynolds numbers, inertia becomes important and momentum transfer occurs at a larger length scale, on the order of small packets of fluid. Such packets, however small, still contain many billions of molecules.\nWith laminar flow, heat is also diffused by molecule bumping into molecule. The <PERSON> number is the ratio of convective heat transfer to conductive heat transfer, given by hD/k, where h is the film coefficient, D pipe diameter, and k fluid thermal conductivity. The film coefficient is a convenient definition, made in the simplest way to capture the essential physics; h = Q/(Ts - Tref), where Q is the bulk heat transferred, Ts the temperature of the heated/cooled surface, and Tref is a reference temperature, chosen for convenience.", "362" ], [ "Q is the heat transferred between the surface across the fluid to where the reference temperature is defined.\nIn the limit of laminar flow, there is really no convection, all the heat transfer is by conduction (diffusion), but not like conduction through a solid, because of the moving fluid. The motion produces a boundary layer and temperature profile, as well as a velocity profile. The Nusselt number is constant only when this temperature profile becomes fixed (fully developed). For the entrance region of the pipe, the profile is still developing, and the laminar Nusselt number is not constant, changing with axial distance.\nThe laminar Nusselt number also depends on the heat transfer make up of the flow. For instance, it's 4.36 with a state of constant heat flux along the length of passage and 3.66 for constant wall temperature, and that's because the shape of the temperature profile is different for these different conditions. Thus, strictly speaking, even with laminar flow, the Nusselt number is not really constant, depending on different flow and heat transfer conditions.\nThe particular number the Nusselt number assumes is not only a function of the flow and heat transfer conditions, but also it's an artifact of the definition of h, the film coefficient. You can call these numbers a \"null point,\" where only conduction occurs and they come about from how the definition of film coefficient is made.\nWith higher Reynolds numbers, inertial effects lead to turbulence, and turbulence increases as these effects become more influential. Velocity and temperature profiles also become fully developed, but they cannot be computed from first principles. Thus, the Nusselt number becomes an explicit function of <PERSON> number, and different correlations serve to provide values for different flow situations. Some correlations work better than others, and it's somewhat of an art to pick the most useful ones.", "108" ], [ "Incompressible Fluid Flow in horizontal pipe segment which encounters tilted pipe segment - Continuity Equation\nSay that we have water flowing horizontally in a pipe of constant diameter. The continuity equation for incompressible fluids, which is a statement of mass conservation, guarantees that the flow rate will be the same throughout the pipe. Given that the diameter is constant it also guarantees that the velocity will be the same throughout.\nNow say the pipe reaches a point where it is tilted. The tilted segment leads downhill and reaches another horizontal segment.\nWater is now going downhill and so it is accelerating. Let us assume an ideal situation with negligible friction and hydraulic resistance.", "1018" ], [ "If the water is accelerating under gravity then velocity must change so I assume the diameter of the water flow itself must shrink and the water will \"stretch\" in order to maintain continuity. Is this actually the case?\nWhat happens at the bottom when the water flow becomes horizontal again? Does it gradually \"bulge up\" at the bottom in order to reestablish the horizontal flow of constant diameter in the lower horizontal pipe? Assuming that the conservation of mass holds and continuity is preserved, the horizontal flow and speeds must be the same in both horizontal pipes.\nOne additional remark on this situation. What if the water were being pumped uphill in a pipe in the same configuration? Is it possible to pump water uphill and maintain a constant velocity in a constant diameter pipe? How can you demonstrate whether it is or isn't from first principles? It seems like water in the pipe would have to slow down when it encounters and uphill segment, but it can't pile up anywhere in the pipe either, and certainly doesn't expand, so it must also preserve continuity somehow I would assume? I feel like I am really missing something.\nI apologize if this question seems trivial or silly. My backgrounds are in chemistry and in geology and I could not find any explanations on the internet regarding this. My fluid mechanics, physical hydrology, and hydrogeology textbooks also were of no help.", "1018" ], [ "The increasing in degrees of freedom are related to an increase of the heat capacity ratio $$\\gamma = \\frac{c_P}{c_V},$$ but not necessarily with an increase in the internal energy of the molecule. The CO2 acts as a greenhouse effect gas because it's much more efficient than NO2 and O2 at absorbing infrarred (IR) radiation:\n* The Sun has a surface temperature of ~5800 K, so most of its radiation is in the visible range of the spectrum. All the mentioned gases are more or less transparent to this type of radiation, so it goes through the atmosphere and reaches the surface.\n* The surface reflects some of this radiation, which again passes through the atmosphere and goes into space, and absorbs the rest. This absorbed energy heats the surface up to ~300 K.\n* Once heated, the surface emits its own radiation. However, most of this radiation is emited in IR because the temperature is much lower than the one in the Sun. NO2 and O2 are \"transparent\" to IR radiation as well, but CO2 is not, so it absorbs the radiation emited by the surface.\n* Again the same, CO2 gets heated by absorbing radiation and emits more radiation.", "184" ], [ "Part of it goes again to the surface, heating it a little more, and we're back in point 3.\nAbout the CFCs, I'm not really sure, but I'd assume they are also good IR absorbers, although their main problem is destroying the ozone layer, but that's a different topic.\nRegarding degrees of freedom (DoF), you can understand them as different kinds of motion a molecule can have:\n* Monoatomic: These are basically dots in the space, so only translational DoF are aviable. All translational motions can be decomposed in 3 dimensions (x,y,z), so DoF=3\n* Diatomic: Two dots joined by a line. On top of the 3 translational ones, we have 2 DoF introduced by rotation (not 3 because the one with the rotation axis aligned with the atoms doesn't qualify as a movement). That makes DoF=5.\n* Triatomic: here it starts to get tricky. If the three atoms are alinged like the diatomic molecule, DoF=5 again. If this is not the case (like for CO2), the extra rotation discarded has to be included, which makes DoF=6.\nPd: vibrations should be included as well, but it's very difficult to make a molecule vibrate, so it's often left aside.", "104" ], [ "This is all about diffusion. The speed of individual molecules is not relevant, because they collide with one another and change direction so frequently (at least at standard temperature and pressure) that this speed does not at all characterize the diffusion of one species into another.\nEngineers have tabulated rate coefficients that describe the rate of diffusion of various gases through air, for example: https://www.engineeringtoolbox.com/air-diffusion-coefficient-gas-mixture-temperature-d_2010.html\nThis doesn't give the rate you'd want, but we can get the ballpark studying a similar rate, Argon diffusing through air.\nSay you've got a can with Argon on the bottom, air on top, and a 1 cm mixed layer between otherwise pure gases.\nJ = (D = 0.189 cm^2/s) * (1.7 kg/m^3 Argon at STP)/(1cm) = 31.8 kg/cm^2/s\nThis is the mass flux of argon through the barrier. Multiply by some area A, Divide by argon density at STP (1.7 kg/m^3), and divide by A again to get argon flow per unit area, areas cancel and we have: = 1.89 cm/s. Note that the Argon mass actually canceled out here too, basically the mix rate just relates to how thick the boundary layer starts out. Initially, when it is infinitesimal, the rate is infinite, since the rate is just D=0.189 cm^2/s divided by the boundary layer thickness L, which I assumed to start at 1 cm.\nThis means that the pure argon below diffuses up into the pure air through the boundary at like 2 cm/s. Of course one second later the boundary layer is 3 cm thick instead of 1, so the rate slows 3x.", "580" ], [ "Three seconds later it is five centimeters thick. You have to solve a differential equation to really get your answer of how long, and the notion of a firm boundary between pure and boundary layer is just an approximation. But roughly... continuing this pattern you hit 21 cm thick \"boundary layer\" after 100 seconds, which I'm guessing is close to your tank size. Double or triple that for the boundary layer to further mix up to your .1% requirement, and we're at 5 minutes.\nNotably, given this surprisingly slow timescale, it probably does help to shake up the tank. I suspect that Argon is a slightly worse case than N2 and O2, but I don't really know. Comparing other gases on the engineering toolbox link, seems like D roughly goes with mass, lighter mass higher D, but Argon isn't very different from air anyway (40 v 29).", "441" ], [ "How Joule-Thomson coefficient is measured experimentally?\nI am reading about Joule-Thomson effect but I can't understand how the respective coefficient $μ$ can be measured experimentally. The Joule-Thomson coefficient is defined as:\n$$μ=\\left(\\frac{\\partial T}{\\partial p}\\right)_H$$\nThat is we are taking the derivative of temperature with respect to pressure at constant enthalpy. But from my understanding this coefficient will be different for different isenthalpic curves. According to <PERSON>:\nThe property measured in the experiment is the ratio of the temperature change to the change of pressure, ΔT/Δp. Adding the constraint of constant enthalpy and taking the limit of small Δp implies that the thermodynamic quantity measured is $\\left(\\frac{\\partial T}{\\partial p}\\right)_H$, which is the Joule–Thomson coefficient, μ. In other words, the physical interpretation of μ is that it is the ratio of the change in temperature to the change in pressure when a gas expands under conditions that ensure there is no change in enthalpy\nDoes this mean that pressure drop must be infinitesimal?\nSuppose an experimenter wants to find $μ$ for a real gas. The setup will be according to <PERSON> the following:\nInitially the gas is in the state $p_i, V_i, T_i$ with the porous plug (another thing I can't get) blocked by the right piston. Now how the gas expands? I mean does the experimenter leave both pistons and because of pressure gradient (force gradient) the gas move to the area of lower pressure? Then he calculates the temperature change and taking the ratio he finds $μ$.", "749" ], [ "But how does he know in which isenthalpic curve this Joule-Thomson coefficient corresponds?\nAlso the initial pressure matters because the derivative is evaluated at a specific $p$. In general (at constant $H$) $μ=f(p)$. So for the same pressure drop but different $p_i$ we shouldn't expect the same temperature drop. How an experimenter takes into account the above in order to find $μ$?\nSo to sum it up my question is how an experimenter measures the Joule-Thomson coefficient for a gas. Also I would be grateful if someone could explain what is the role of the porous plug. I am an undergraduate Chemistry student so unfortunately I don't have a theoretical background in fluid mechanics/dynamics. I am disappointed because although I can get the maths I don't understand this experiment which I could say seems very simple. I have spent a lot of time trying to understand the device/experimental setup but didn't make it.", "749" ] ]

[ 8545, 9472, 6334, 2628, 4389, 6034, 1278, 1063, 7045, 6620, 6235, 2633, 11186, 8613, 8845, 10184, 3080, 6283, 6289, 8641, 4676, 6323, 1500, 5327, 9388, 2119, 785, 8201, 3070, 3449, 5223, 1607, 7549, 6102, 3335, 1347, 6237, 7600, 5550, 5553, 1924, 4235, 1584, 3781, 4801, 681, 9847, 3744, 10794, 9577, 4009, 9288, 1731, 4472, 1369, 6860, 1408, 3686, 4861, 6730, 2125, 3232, 569, 8316, 8124, 7130, 8805, 1006, 1952, 4095 ]

[ [ "Last Tango in Paris\nIncredibly difficult to watch, both as a story and metatextually.\nTaken at face value, everything is so raw and so natural. The performances are layered with such realism and sorrow. Plus the way <PERSON> and company shoot Paris is extraordinary, showing the suburbs and side-streets of the city with an identity all their own. The few landmarks used, such as that bridge from Inception, are made to stick out.\nThe bleakness of the scenario goes from beginning to end, but the film builds to a conclusion you know will provide only sadness. Thankfully you have the aging <PERSON> to play a man lost in his youth, put opposite the wise-beyond-her-years <PERSON>.\nBut with knowledge of how the film is made and the toll it took on <PERSON> in particular, The infamous rape scene has been the subject of scrutiny for years, and for good reason.", "306" ], [ "Even though it is supposedly simulated, I've never felt so disturbed by a rape sequence, nor felt the pain so much of the subject. Even in the context of the film the act plays out with a marked lack of consent.\nBut this isn't the only moment that disturbs and upsets, with so much of <PERSON>'s performance feeling manipulated and extorted. She's a stunning force opposite <PERSON>, the babe in the woods to his big bad wolf. Yet you cannot deny the talent of her actual acting, building a world-weary teenager who nevertheless feels as emotionally old as <PERSON> looks. We're not watching a <PERSON> and <PERSON> dynamic between the characters, but a bond between two adults who are afraid of growing beyond the roles they've made for themselves.\nBut what happens, say, when those roles are forced in place, are dictated, are abused?\nIn a film like Last Tango in Paris, where does performance end and trauma begin? This is what leaves you on the verge.", "306" ], [ "<PERSON> and <PERSON>\nReally remarkable stop motion here, with <PERSON> elevating his game even higher. It's in the fine details of fast movement and in the jumps and gravitational bits. So good. His command of how things move and have weight has always been phenomenal, but he's improving all the time.\nHis cinematic chops are also extending. he's using camera overlays including bits of hand drawn animation.", "594" ], [ "He is cross cutting action sequences and he's using multiple angles of the same action.\nAs parable, this isn't much, but it is a pretty devastating rip on the bourgeoisie. Because of his use of insects and animals, we see thee creatures as ourselves - and so here we see ourselves as rats. Not entirely comforting. And if I did have a minor quibble, it's that even though he is now animating the faces of these rate, it does move the piece a little further into pastiche because they no longer look like real animals, but closer to cartoon versions. Its something that was bound to happen if he wanted this level of characterization, but it is a trade off. Still, this piece has some great stuff.", "862" ], [ "<PERSON>\nI was originally unsure what to make of the ending, which seemed like it may have existed primarily to shock, but <PERSON> makes a very strong case as to how the film contrasts two different losses of innocence (the provocation is therefore not in the suddenness and violence of the ending, but that <PERSON>'s initiation is actually less painful than <PERSON>'s).\nThe encounters between <PERSON> and <PERSON> are wonderfully shot, playing out mostly in tense long takes but cutting to <PERSON>, peeking between her fingers one instance and sobbing, back to her sister, in others. I was also impressed by <PERSON>'s lighting in this scenes and her tendency to blowout faces and play with light and shadow against walls. <PERSON>'s style is quite simple in the sense that her shots are not themselves complicated or flashy, but she mixes them brilliantly to control the tone of the film and point the viewer to certain thematic parallels and upset simple interpretations.", "529" ], [ "Poor Things\nI read the book this month and it instantly became one of my favourites. It is such an amazing and many faceted piece of literature that it is hard not to see this film now as a slight failure. There is a lack of ambition in how <PERSON> drops the setting, the framing structure and some level of mystery. It feels like the <PERSON> of 10 years ago might have tried and failed, but perhaps the sense of <PERSON> now is not to try at all. He instead hones in on specific elements of the novel, playing them to perfection.", "647" ], [ "It'd just hard for me not to spend a little time imagining what could have been.\nWhat’s left is a masterpiece in its own right. As so much is excised to focus on the mental journey of <PERSON>. The cinematography, costumes, score, production design. All emphasising what it is like to see the world through the eyes of a child, to be free of worldly pressure, but in <PERSON>’s unique case not to be treated as a child or to know the feeling of being under authority. Perhaps it would be better for the world if we were all afforded such a luxury.\n<PERSON> is sensational, but as is the full cast. <PERSON> really just cannot miss an opportunity to do a perfect line delivery.", "529" ], [ "Drive My Car\nThe first <PERSON> I saw was this year's Wheel of Fortune and Fantasy and it was a revelation. I was so blown away by it that I fear I may have let comparison and expectation rob me of a sober engagement with Drive My Car. This second <PERSON> is clearly the work of an emotionally sophisticated and visionary auteur, but I found it much too neat and a little contrived to fully engage with it. I haven't read any <PERSON>, but this felt constrained by the kind of conventions one finds in literary fiction, the kind that frequently turn me off to such writing. A defense of the work could easily point out that this is kind of the point: the conventions of the theater, <PERSON>'s rhythmic methods, and the parallels of art and real life are clearly animating the work.", "83" ], [ "And it's depiction of grief as a kind of repetitive numbness is really quite brilliant. But it was precisely these connections, along with some its narrative symbolism, that just felt a little too calculated for emotional effect. There were passages of brilliance, of course, and moments were I was quite moved. But this felt constrained and at 3 hours, often quite dull. I will give this another view some time in the future, perhaps after I go back and see his other films.", "831" ], [ "The Zone of Interest\nWatching this film was annoying, but part of the discourse surrounding it is even more hollow. There's no such thing as an \"unethical\" way to portray a tragedy, unless a filmmaker CLEARLY misrepresents factual events to deny the harm that was done to the victims, or in order to attack them in any way, shape or form. Cinema is a lie that tells the truth. Whether you see a particular film as \"entertainment\", it is still part of the postmodern desert we inhabit as viewers where we consume ourselves in media through which our history, desires, identity, thoughts are replicated and sold to us as products. These filmmakers want your money and adulation just like anyone else selling you a commodity. So to scoff at Schindler's List in your praise for this film is silly.", "133" ], [ "This movie's supposed metatextuality doesn't make it any less exploitative. If one were to make the argument that this is yet another film in the profitable, Oscar-reaping enterprise that Hollywood has manufactured through its commodification of the Holocaust, it'd be valid.\nNow onto the movie...\nMy gripe with this film is that it doesn't justify its runtime. Once you realize that there's no real plot, the juxtaposition of quotidian nazi life at the forefront and the steady thrum of the Auschwitz massacre in the background gets old pretty quickly. Lots of people have described this movie as a chilling, frightening watch but, I mainly felt boredom, especially past the halfway mark.\nThere's no shortage of great films depicting the banality of evil. The difference is that they do it through much more engaging narratives. One of my all-time favorite films is <PERSON>'s The Conformist. Just like The Zone of Interest, it's a movie showing the banality in which a bureaucrat/duty-bound soldier engages in fascist ideologies but it's more subtle and less monotone in its approach.", "269" ], [ "I'm Thinking of Ending Things\n<PERSON> compared this to Eraserhead on Twitter, which got me thinking about why this doesn't work for me when <PERSON> does.\n<PERSON>'s work, much like his characters, is extremely self-conscious. He's the exemplar of what <PERSON> called the \"mind game film,\" which are more colloquially recognizable as the critically acclaimed, usually semi-independent films with twisty or ambiguous narratives that tend to attract cult followings. <PERSON>, unlike <PERSON> (and also <PERSON> or films like The Usual Suspects) is self-conscious of his place within this field; his films tend to deal with artistic creation or pound away at the fourth wall (even if they stop short of breaking it). I'm Thinking of Ending Things central character is poet and painter, and productions of Oklahoma! figure into the narrative. The protagonist quotes <PERSON> at length in discussions of A Woman Under The Influence, and she and her partner discuss <PERSON> and <PERSON> and <PERSON>. They even briefly argue about the politics of \"Baby, It's Cold Outside.\" I don't think the film is encouraging a particular have a point of view on <PERSON>'s criticism or <PERSON>'s proclamations about \"happy families.\" At times they reinforce the film's Big Theme, the Unstoppable March of Time, but more than underlining his theses, I think <PERSON> knows that his audience will delight in seeing their own interests reflected back at them on screen, and I think that is why <PERSON> works for me and <PERSON> does not.\nWhen <PERSON> uses <PERSON> in Mulholland Dr and <PERSON> in Lost Highway, or Nine Inch Nails and <PERSON> mere minutes apart, it is evidence of authorial perspective and diversity of interest that marks his entire body of work.", "80" ], [ "Eraserhead plunges you deep into the psych of its protagonist, and although its women are noir tropes, those are tropes whose power Lynch believes in earnestly (the prevailing theme of <PERSON> work, exemplified in the Club Silencio scene in Mulholland Dr, is that there is something genuine and real and powerful in what is false or imaginary).\n<PERSON>'s work is instead marked by a deficit. His interests show up in the things his characters discuss, and the are never deployed with the specificity so remarkable in <PERSON>. It's telling that the \"Girls Just Want To Have Fun\" allusion, a pop/lowbrow one that is unusual for <PERSON>, is in Anomalisa, a film that formally asks us to see its characters as something \"less than.\" It keeps us so firmly rooted in the protagonist's subjectivity that we are unable to break out and appreciate a very earnest love for a silly pop song as something genuinely liberating for the character. I'm Thinking of Ending Things' sin is no more forgivable;, it invokes other art primarily as affectation. The narcissistic insecurity of <PERSON>'s characters seems to reflect the same trait in <PERSON> himself, desperate to prove the critics his novel Antkind parodied that he does, in fact, have something to say.\nPerhaps he does. My challenge to him would be this: say it.", "285" ], [ "Anatomy of a Fall\nA movie about how deeply unserious and misogynistic the French are.\nIt doesn’t really do much new that other family-centered courtroom dramas haven’t done better save for exposing the many, often tiny biases against women that are engrained in society. The opposite of that same preconception that helps <PERSON>’s case in Kramer vs. Kramer mixed with <PERSON>’s uphill battle in Marriage Story.\nFunny how mockumentary-ish the filmmaking was at points, which was clearly meant to evoke immediacy but instead took me out of it.", "306" ], [ "It works to its favor that it’s helmed by an immaculate leading performance. <PERSON> carefully balances fear and doubt and so much constrained emotion. She probably won this the Palm d’Or all by herself.", "464" ] ]

[ 3267, 5517, 10569, 9906, 1280, 3378, 2147, 4488, 3119, 8763, 2945, 7667, 7960, 4057, 2164, 9086, 11202, 2811, 296, 385, 8266, 4873, 3085, 3301, 9313, 4338, 1373, 6829, 9408, 215, 6785, 11012, 3444, 7349, 7206, 2735, 7943, 1487, 207, 1858, 6960, 5904, 7040, 11220, 473, 8082, 8840, 8541, 3625, 3802, 5042, 2394, 2191, 10954, 3158, 5644, 8437, 1651, 9642, 479, 5426, 3841, 11177, 7326, 1350, 2689, 2365, 4426, 5554, 2630 ]

[ [ "Regression model for a count proces\nIn R I have data where head(data) gives\nday count promotion\n1 33 20.8\n2 23 17.1\n3 19 1.6\n4 37 20.8\nNow day is simply the day (and is in order). promotion is the promotion-value for the day. It is simply the number of times an advertisement has been on television. count is the number of new users we got that day.\nI want to investigate the impact the promotion-value has on new users (count). Since we have a count process I thought it would be best to make a poisson regression model.\nmodel=glm(formula= data$count ~ data$promotion, data=data)\nWhen we type summary(model) we get\nCoefficients:\n(Intercept) good_users$promotion\n13.40216 0.24342\nDegrees of Freedom: 793 Total (i.e. Null); 792 Residual\nNull Deviance: 9484\nResidual Deviance: 9325 AIC: 12680\nHere is a plot of the data.\nBut when I plot the fitted values for the model\npoints(model$promotion, model$fitted, col=\"blue\")\nwe get this\nHere is another plot that shows the same but where days with 0 promotion are removed.\nHow should I chose my regression model (should I use lm instead of glm) or is the another better approach to solve this? Because the data is not pretty but more random like this what should one do ?\nUpdated\nFinding the sweet spot\nI have done the following for finding a sweet spot. I divide data into 10 groups.", "650" ], [ "group1 is simply a subset where the promotion-value is within 1:10. group2 is data where the promotion-value is between 11:20, and so on for the other groups. So in R we have\ngroup1 <- subset(data, data$promotion %in% 1:10)\ngroup2 <- subset(data, data$promotion %in% 11:20)\ngroup3 <- subset(data, data$promotion %in% 21:30)\n...\ngroup10 <- subset(data, data$promotion %in% 91:100)\nNow I can use wilcox.test to test if there is a significantly difference between the groups by typing\nwilcox.test(group2, group1, alternative=\"greater\")\nwhich gives a low p-value, ie group2 has significant higher new_good_users than group1. The same goes for\nwilcox.test(group3, group2, alternative=\"greater\")\nbut for wilcox.test(group4, group3, alternative=\"greater\") I get a p-value at 0.20, ie there is no significant difference in new_good_users between group4 and group3. And the same goes for the rest of the group-pairs up to 10.\nSo this must mean that if we increase promotion in the first groups we have an increase in new_good_users but in the last groups we do not have that increase. This means that we have a sweet spot at group3 where the promotion-value is 21:30. Is this not correct ?", "650" ], [ "Chose the right regression analysis\nIn R I have data where head(data) gives\nday promotion profit new_users\n1 105 45662 33\n2 12 40662 13\n3 44 46800 20\n4 203 54102 46\nNow day is simply the day (and is in order). promotion is simply the promotion-value for the day, the profit is the profit that day and new_users is the number of new users that day.\nI want investigate the relationships between promotion to profit and new_users. We see a clear positive correlation between promotion and profit, and there is also a positive correlation between promotion and new_users. In R I simply test correlation\ncor.test(data$promotion, data$profit, method=\"kendall\", alternative=\"greater\" )\ncor.test(data$promotion, data$new_users, method=\"kendall\", alternative=\"greater\")\nwhich both gives a low p-value, ie we have a positive correlation.\nI want to find a point where where the increase of promotion don't increase profit or new_users that must, ie a sweet spot.\nHere is 2 plots and the R code for these\nplot(data$promotion, data$profit, col=\"brown\")\nplot(data$promotion, data$new_users)\nHow should this be done?\nMy thoughts where to make a regression model. For the first one \"promotion vs.", "650" ], [ "new_users\" one could use a poisons model because it's a count-process, so a model like this would be a good chose?\nglm(formula= data$new_users ~ data$promotion, family=\"poisson\", data=data)\nNext what regression model should one chose for the next one. Is it fair to say that this regression model is a good chose ? (I use sqrt command)\nglm(formula=data$profit ~ sqrt(data$promotion) , data=data)\nOr maybe it's not even necessary to use a regression model at all to find a sweet spot?\nThanks.\nI have now looked at 'good' new users. For each day we have a promotion value and we have a count value which is the number of new good users. This plot shows us the number of good new users we get for a promotion for each day. For example for promotion value 90 we have a day where we got 8 new good users and a day where we got 14 new good users.\nWhat would be the right approach to find a sweet spot for the use of promotion ?", "587" ], [ "How to create a prediction interval with the fact that the residuals follow a specific distribution (in python)\nI am looking at a software development pipeline where I am predicting the lead time of different products flowing through the pipeline.\nAfter applying a boxcox transformation on the lead time (target variable) and creating a XGBoost regressor model I can see that the residuals follow a t-locationScale distribution.\nSo now I looked at this guide which describes a method to create a prediction interval for any regression model assuming that the residuals are normally distributed. https://qucit.com/a-simple-technique-to-estimate-prediction-intervals-for-any-regression-model_en/\nBut I tried to tweak it to my distribution.\nSo a t-locationScale distribution has a $\\sigma$, $\\mu$ and $\\nu$ parameter. The variance is only defined for $\\nu>2$.", "509" ], [ "My specific distribution has $\\nu = 2.56$ and $\\mu = 0.04$, $\\sigma = 0.97$ So I could take the 95% interval of this distribution and say that for any $\\hat{y}$, the prediction interval is the 95% interval of the residual distribution.\nBut I want to take into consideration that the prediction interval should change with different inputs. I created a regressor model, which I trained and then made predictions using the validation set. I then took the square of the error and trained an additional error model on this data. Such that the error model could predict the variance of the residuals distribution.\nxgb = XGBoostRegressor()\nxgb.fit(X_train,y_train)\ny_hat = xgb.predict(X_val)\nval_error = (y_hat-y_val)**2\nxgb_error = XGBoostRegressor()\nxgb_error.fit(X_val, val_error)\nvariance_hat_residuals = xgb_error.predict(X_test)\nThe relationship between variance and $\\sigma$ and $\\nu$ for a t-locationScale distribution is\nvar = $\\sigma^2 *\\frac{\\nu}{\\nu-2}$\nNow here is where I make an assumption which I am not sure makes sense.\nI assume that the degrees of freedom $\\nu$ is the same as for all residuals, $\\nu = 2.56$ and then I solve for $\\sigma$ through the following.\n$\\hat{\\sigma} = \\sqrt{\\frac{\\hat{var}*(\\nu-2)}{\\nu}}$\nAnd estimate the lower and upper quantiles from this distribution.\nresidual_distribution_lower_quantile = scipy.stats.t.ppf(q = 0.025, df = 2.56, scale = sigma)\nresidual_distribution_upper_quantile = scipy.stats.t.ppf(q = 0.0975, df = 2.56, scale = sigma)\nI then predict the lead time $\\hat{y}$ and say that the mean of the distribution is $\\hat{y}$\npred = xgb.prediction(X_test)\nlower_interval = pred + residual_distribution_lower_quantile\nupper_interval = pred + residual_distribution_upper_quantile\nDoes it make sense to make the claim of $\\nu$ is static? My score for the prediction interval is now $81\\%$ since I am clearly simplifying the problem.\nAny suggestions for improving my method?", "509" ], [ "R - Function for 10 fold crossvalidation\nI have written a function for 10 fold crossvalidation that I want to use for different models, e.g PPR, MARS. However, I get an error when running it and I cannot figure out why it does not work? My CV function:\ncv10 <- function(reg.fn, formula, dataset, ...)\n{\nset.seed(201)\n### Number of observations\nnrow <- nrow(dataset)\n### Create a permutation of the observations indices\nInd <- sample.int(nrow,nrow, replace = FALSE)\n### Compute the size of each of the 10 folds\nM <- nrow / 10 # 'fold size'\n### Initialize the score\nscore <- 0\n### The first fold will then contain the observations which correspond to..\n### ..the indices of the first M elements of Ind.\nfor(i in 1:10){\nbeg <- i*M\nend <- (i+1)*M\n### Data to train the model\ndata.train <- dataset[Ind[-beg:-end],]\n### Data to test the model\ndata.fold <- dataset[Ind[beg:end],]\n### Fit the model\nmodel <- reg.fn(formula,data=data.train,...)\npredicted.y <- predict(model,data.fold)\n### Update the CV-score\nscore <- sum((predicted.y - data.fold[,1])^2) / M\n}\nreturn(score/10)\n}\nTesting using ppr:\ncv.scores <- numeric(10)\n### Some code\nfor(i in 1:10){\nscore <- cv10(reg.fn = ppr, formula = y~.,\ndataset = data, nterms=i)\ncv.scores[i] <- scores\n}\ncv.scores\nThe traceback:\nError in matrix(NA, length(keep), object$q, dimnames = list(rn, object$ynames)) : length of 'dimnames' [1] not equal to array extent 4. matrix(NA, length(keep), object$q, dimnames = list(rn, object$ynames)) 3.", "613" ], [ "predict.ppr(model, data.fold) 2. predict(model, data.fold) 1. cv10(reg.fn = ppr, formula = y ~ ., dataset = data, nterms = i)\nThe data I am using:\nstructure(list(y = c(23.<PHONE_NUMBER>, 27.8893494373006, 3.32468370559938,\n-13.5852336127512, -5.14668013186906, -<PHONE_NUMBER>, -14.328750654513,\n-4.26428395686341, -2.75486620989581, 17.3107345018601, 25.6193450849393,\n<PHONE_NUMBER>, -1.30909806542865, 2.<PHONE_NUMBER>, -19.1193524499977,\n-1.46508279385589, 2.65778970954973, 14.8513018374104, -2.87449028138997,\n1.37368992108124, -1.43518738939116, 0.0199676357940499, -1.549025998582,\n-4.<PHONE_NUMBER>, -9.15130335901099, -2.62794216480131, -1.68473200963303,\n3.15144283445608, 7.78027589015824, 9.<PHONE_NUMBER>), x1 = c<PHONE_NUMBER>,\n-<PHONE_NUMBER>, 0.325763726232689, -1.69658096808073, -1.2854825202758,\n-0.<PHONE_NUMBER>, <PHONE_NUMBER>, 0.<PHONE_NUMBER>, -2.30403430891787,\n0.189004139305415, <PHONE_NUMBER>, <PHONE_NUMBER>, <PHONE_NUMBER>,\n1.01347438447768, -<PHONE_NUMBER>, <PHONE_NUMBER>, 0.207342703528518,\n0.", "856" ], [ "How should one interpret heritability? Is it related to $R^2$?\nFrom Wikipedia:\nHeritability estimates are often misinterpreted if it is not understood that they refer to the proportion of variation between individuals on a trait that is due to genetic factors. It does not indicate the degree of genetic influence on the development of a trait of an individual. For example, it is incorrect to say that since the heritability of personality traits is about .6, that means that 60% of your personality is inherited from your parents and 40% comes from the environment.\nSo what is the plain english interpretation of heritability?\nIs it supposed to be the genetics version of $R^2$? If so, please explain it to me anyway because I forgot my statistics.\nI found this so from what I understand, one might say:\nIf height is estimated to be 80% heritable, and if we get 10 people, get their heights and then compute the variance, we say that around 80% of that variance is likely due to genetic factors while the remaining 20% is due to other things.\nSuch interpretation of heritability seems to work for non-categorical traits. What about categorical or binary traits?\nHair and eye colour is categorical (I think?).", "882" ], [ "So what, we assign a number for each colour and then compute the variance?\nADHD is binary (I think?). Do we assign 0 for not having and 1 for having then compute variance?\nI seem to recall regressing binary or categorical variables needs some kind of adjustments and hence interpretations of estimates (such as intercepts or slopes) may be different.\nAlso, the book linked above says\nheritability represents the degree to which the variance in a trait is attributable to genetics in the population on average\nCombining that with the Wiki paragraph above, I don't think someone saying\nEye colour is around 98% heritable. I have brown eyes. Therefore, around 98% of the reason why I have brown eyes is genetics.\nis far off from saying\nIf we have a million people who near-identically flip a million near-identical coins a hundred times, and we compute the average of the coin flips that turn out to be heads to be 58.6, then the probability that you will flip heads when you near-identically flip this near-identical coin is around 58.6%.\nIs it? (Of course 'near', 'around', etc are not always used similarly...lol)\nSo yeah, technically the 60/40 interpretation in the Wiki example is technically wrong but practically it's around 60% $\\pm$ some standard deviation?", "655" ], [ "Creating a complex featureset for regression modeling\nI am currently working a on project that requires me to convert all of the categorical variable to continuous (or binary) variables to build a regression model. The problem is that I am more than 100 categorical values and all of them have different measures. For example, let's say that users who have different types of cars and all of those car models have associated continuous variables such as the price of the cars, size of gas tank, avg price of the gas to fill the gas tank and etc. Here is the example of this dataset below:\n| user | car_make| car_model| price| gas_tank| full_gas_tank_price| | -------- | -------------- |----|--|--| --| | 123_a | Honda | civic| 17000| 12| 19| | 345_b | Lexus | RX| 45000| 16| 35|\nOne way to rebuild this featureset to only contain continuous variables is have the car_make and car_models as columns that each could contain the price, gas_tank and full_gas_tank_price values. For example:\n| user | Honda_price| honda_gas_tank| honda_full_gas_tank_oprice| Lexus_price| Lexus_gas_tank| Lexus_full_gas_tank_price| | -------- | -------------- |----|--|--| --|--| | 123_a | 17000 | 12| 19| 0| 0|0| | 345_b | 0 | 0| 35| 45000| 16|35|\n(I have not included the columns for civic model and RX model because the table is going to be wide). So, if I create the table like above, the table is going to include too many columns.", "856" ], [ "Becuse for each car_make and also car_model, there are 3 different features. So, I decided to create my featureset in a way that all of the car_make and car_models are binary variables and then have other continuous features as they are. Here is the example of the table:\n| user | Honda| Lexus| civic| RX| price| gas_tank| full_gas_tank_price| | -------- | -------------- |----|--|--| --| --|--| | 123_a | 1 | 0| 1| 0| 17000| 12|19| | 345_b | 0 | 1| 0| 1| 45000| 16|35|\nThis sounded reasonable to me because I would have less features, hence, better performance. However, I was a bit worried that it would affect the model's accuracy because this table does not specifically show the price of honda. Is just shows that the user has honda and then the price is on another column. What do you think?\n(I understand that I can potentially remove features that don't correlated with the output, but let's assume that all of the existing features correlate with the output but there are just too many of them)", "946" ], [ "Here is the code I wrote to answer my question. It might not be the most efficient one but it works. Sharing is caring :)\nniter<-10000\nN<-nrow(Y)\nT<-10 # I will take into consideration until t=10 to estimate my parametres and then I will forecast the rest values t=11,12,... etc\nresult <- matrix(0,nrow = niter, ncol = 3) #Here I store 3 parameters: alpha, sigma_epsilon, sigma_eta.", "416" ], [ "Feature Selection Statistical Test for Nominal Response Vs Continuous Predictors? (in R)\nI cannot find much information on this, none so-far useful.\nI have a sparse data set with 17K+ columns of continuous gene expressions, an example of a typical column: (3.15, 0, 7.1294, 0, 0, 0, 2300.2, 213.444,...) and each row has an associated nominal response of celltype = 'A', 'B', 'C', 'D', 'E'. These are names, hence nominal, and not ordinal.\nThus, there are 17308 gene expression columns, and a single response column in my dataframe, with 4954 rows/samples.\nI am trying to find the right statistical test to perform a filter-method for feature selection (taking the best 1000 low-correlation p-values obtained through some statistical test). My teacher mentioned Wilcoxon rank sum test, but I dont see how this applies, nor ANOVA. I found the Kruskal-Wallis as the only relatively good test. I do not come from a statistics background, having only taking Mathematical Statistics I in university.\nI use a File Backed Matrix (FBM from bigstatsr package) to assign the p-values in a foreach loop, as follows:\nforeach(i = 1:num_feats, .combine = 'c') %dopar% { dat_total = cbind(df[, i], df$ctype) p_vals[i - 1, 1] <- kruskal.test(df[, i] ~ df$ctype, data = dat_total)$p.value } but this results in about 12000 p_values stacked up at zero... (?)\nI also tried switching df[, i] ~ df$ctype for df$ctype ~ df[, i] but kruskal.test in R asks for response ~ group, regardless, when I do this I get a bimodal distribution of p-values: a few thousand stacked up near 0 (but non are zero) and a few thousand stacked up near 1 (some equal to 1). I read more on this as in 'Section C' found here.\nI'm supposed to just test each column against the response, check for significance, peel off the best 1000, and then generate a feature reduced matrix df_sml that I then feed into elastic net, lasso, linear discriminant analysis and a classification tree.", "655" ], [ "What I did however was pick the best <PHONE_NUMBER> p-values, and pick the top 1000 that had correlation between -0.25 and 0.25 (LDA was failing otherwise).\nANY tips are appreciated, I don't see the point of deriving a test data set for reproduction. This(and several other) articles mentioned Kruskal-Wallis for categorical dependent versus continuous independent variables (but my concern is I am feeding them in 'backwards' to the test in R).\nI dont understand why I would possibly want to factor celltype into a dummy variable, as this is nominal data and not ordinal data, so any explanation regarding that appreciated. If it is okay, why? Doesn't ordinal data imply rank? And if I am treating the dummy variable as factor, how is that different than treating 'A', ..., 'E' as factors?\nThe simplest method you can suggest would be most appreciated, hence my turn to Kruskal-Wallis and not some of the more complicated and involved methods I have seen suggested (I likely wouldn't have the time to implement them).\nedit: I wanted to add a few things: I ran elastic net for alpha = 0.1:0.9 by 0.2 and LASSO, and I am getting a classification accuracy rate around 0.98 for all of these. So unless something is amiss, my models are getting pretty good results, LDA performed just slightly worse (0.96) than Elastic Net (glmnet), the Tree model with pruning (0.76) was garbage lol. And this was using df$ctype ~ df[, i] which is group ~ response, not the desired format by kruskal.test as far as I know. {see ?kruskal.test(formula,...)}\nedit2: I wanted to add, there are like 8K+ columns with 95% entries being zero, but the teacher said to leave them in and do this test instead (this data is for a machine learning course midterm project), which I've read can be what is contributing to the wild number of p-values stacking up at or near 1. I originally stripped these columns from the dataframe.", "458" ] ]

[ 8706, 6172, 2118, 3892, 6663, 7845, 247, 2800, 5563, 3428, 8302, 9267, 4890, 6348, 6259, 7177, 1053, 6625, 4192, 6350, 5071, 1831, 4466, 1669, 7327, 1089, 1091, 1384, 10905, 5364, 4280, 10157, 801, 8592, 4620, 7754, 3195, 3356, 6814, 9773, 11226, 2866, 1890, 10387, 11154, 7268, 6379, 4847, 4997, 1122, 876, 1345, 7050, 2018, 8422, 10251, 10110, 3717, 10549, 585, 904, 2257, 4703, 4336, 9324, 9467, 8819, 1610, 11423, 10174 ]

[ [ "Part of the argument can be reasoned without using any \"heavy handed\" general-relativity, but it is a long road.\nPart 1: Relativistic objects are \"pulled toward\" gravitational sources more than predicted by newtonian mechanics. Light is pulled twice as much. This needs general relativity, see here.\nPart 2 Pressure results from exchange of moving particles. In an ideal gas, the moving particles cause pressure. In a solid of liquid, it's more complex. There is degeneracy pressure and attractive forces that allow object to exist in tension. This is due the the exchange of negative energy virtual photons.\nA system under pressure (such as a hot gas) contains moving particles that have \"extra\" gravitational attraction to our test mass. Conversely, our test mass feels an extra attraction to these particles. Although the kinetic energy of the particles contributes to the total mass and thus the gravity, the pressure creates extra gravity beyond that of the mass and kinetic energy alone.\nAn example: Consider a thin hollow spherical mirror filled with photons (again, we are working with a weak gravity source).", "343" ], [ "We place a test mass (that does not interact with light) just inside the mirror. Due to the shell theorem we need only consider the tiny amount of mass/energy that closer to the center of the sphere than our test mass. The Newtonian calculation would be G(our_mass)(energy_of_photons)/r^2, but the actual force is twice that due to the pressure. If we are outside the mirror the newtonian formula again applies. Although there is pressure inside, there is tension in the walls of the mirror, in effect it is a a balloon inflated with photons! The pressure and tension terms cancel themselves out. When you are outside of a spherically-symmetric object, only total mass matters and the internal pressures will always cancel.\nWhen pressure is due to gravitational compaction you can't escape hard-core relativity if you want to account for it: On earth, the pressure contribution to gravity in the core is only 1e-9 of the density (mass) contribution. This \"tiny\" amount of pressure isn't canceled out by tension as in the case of our mirror balloon. However, to understand why it gets canceled out we would need to invoke full-beast-mode-general-relativity because relativistic effects are also 1e-9 as strong as Newtonian gravity for Earth (no it's not a coincidence that both are 1e-9). Pressure is only important, in comparison to density, when P ~ (density)c^2, and that c^2 makes even core-of-Earth pressures look small.", "343" ], [ "Attractive higgs force and inflation\nInflation was the extreme accelerating expansion of the universe, see here: http://en.wikipedia.org/wiki/Inflation_(cosmology) It worked in a similar way to dark energy but was so strong it would easily tear atoms apart (if it wasn't far to hot for atoms to form in the first place).\nThe weird thing about inflation and dark energy is that they are under tension.\n[Optional reading]: Explanation of how pressure works backwards in general relativity\nIn general relativity, pressure itself is attractive. This is not because it takes energy to compress materials, the energy put in to compressing something simply shows up as extra mass. This is an extra effect.\nSuppose you dive deep into a (non-rotating) neutron star (pretend the center is liquid) and measure the central density (as a swimmer would gauge the inertial resistance of water). You then move 1mm away from the core, release a pellet of dark matter (which goes right through everything so it has no buoyancy), and measure the acceleration towards the center (because of the shell theorem and the slow maximum speed of the pellet (~10 m/s), you can assume newtonian gravity in the local vicinity).\nThe measured acceleration will be greater than the calculated acceleration, up to almost twice as much. This is a consequence of light bending twice as much as \"expected\" and can be derived from special relativity using a reference frame with constant acceleration.\nPressure is equivalent to an exchange of fast-moving particles. These \"virtual\" particles \"bend more\" toward a mass and conversely the mass is pulled back more toward it.", "781" ], [ "The inflation field was under enormous tension, which is the exchange of negative mass particles, and it created a repulsion. Another effect is that work must have been done on the inflation energy as space expanded, just as it energy is added to a rubber band when you pull on it. This work showed up as more inflation energy, and meant that it does not dilute when space expands. Eventually, the pressure/density ratio, (equation of state) went above the critical value of -1 and the field began to dissipate. The -1 \"critical value\" also causes that the fluid to be <PERSON> invariant, which means there is no preferred reference frame.\nThe question itself\nThe Higgs particle is a purely attractive force, see here:\nhttp://profmattstrassler.com/articles-and-posts/particle-physics-basics/the-known-forces-of-nature/the-strength-of-the-known-forces/\nCould the Higgs force create a strong enough tension (perhaps with help from other forces?) to overwhelm the positive pressure effects of quantum degeneracy and heat and leave enough tension to cause inflation? If so you would not need GUT or TOE speculations for the mechanism of inflation. Furthermore, you could quantify it's strength and the nature of it's eventual decay.", "651" ], [ "As the orbit speeds are far below $c$, relativity doesn't matter. The fact that it is a black hole doesn't matter either-it could be a star of the same mass. The gravitational field of a spherical object is the same as a mass point at the center as long as you are outside the object. It takes a lot to change the momentum of the earth that much. The only thing I can think of to eject earth from orbit is to have another massive body come flying through to slingshot the earth away from the black hole. Does that work for you?\nAdded: Here is how I would think about it. You need an orbit simulator to get it really right. I believe there is a free version of Satellite Tool Kit and there must be others on the web. For simplicity, let everything happen in a plane. You need a big body, call it A, to transfer this much momentum to the earth. I would guess 30-100 earth masses, but you might wind up with more. Figure out what velocity change you want the earth to have.", "921" ], [ "I am hoping we can think about the two events separately and let the simulator patch them together. The first is A falling in from infinity on a parabolic trajectory. When it passes earth's orbit, it will be travelling $\\sqrt 2$ times faster than earth. We get to pick the direction, which will be set by the angular momentum of the system. The second is the scattering of A and earth, which we analyze in their CM frame, ignoring the black hole. I think it will be so fast that will be OK. Decide what velocity change (as a vector) you want the earth to feel. Find a set of parameters (incoming velocity and miss distance) in the A-earth frame that results in that velocity change for earth. Now find an angle for A to cross earth's orbit that results in the proper relative velocity of A and earth in their CM and direct A to cross earth's orbit at the correct distance from earth. Try it and see if it works. You only have three parameters-the mass of A, the angular momentum of A around the black hole, and how far ahead of earth A will cross the orbit before you allow for the A-earth interaction.\nLet me know how it works. No guarantees.", "675" ], [ "We don't know and you can make up the effect you want. The answer given above correctly sums up our current understanding of black holes and gravity. However, currently we can't reconcile our understanding of gravity (which explains black holes) with our understanding of quantum mechanics (which explains mater/antimatter interaction). In other words, \"nothing will happen\" ist not something we know but something we'd need to test in an experiment.\nIf you want a spectacular effect, you can make one up: During matter/antimatter annihilation, the mass/energy stops to have gravity for short moments (due to quatnum gravity effects we have not been able to observe yet, because they are to weak when we do these experiments with single atoms in a collider). This allows some mass and or radiation to escape (either in direction with the spin of the BH, or as a jet along the axis of rotation). Also the on/off sends strong gravitational waves.", "343" ], [ "Some of the emitted matter/energy lumps may be dense enough to form black holes themselves, they may loose momentum when interacting with the accretion disks and fall back into the large BH ...\nThe shape will be weird - wikipedia has this to say about a black hole merger: \"As two black holes approach each other, a ‘duckbill’ shape protrudes from each of the two event horizons towards the other one. This protrusion extends longer and narrower until it meets the protrusion from the other black hole. At this point in time the event horizon has a very narrow X-shape at the meeting point. The protrusions are drawn out into a thin thread. The meeting point expands to a roughly cylindrical connection called a bridge.\"\nOne question that a reader with a good grasp of physiscs will have is when this cataclysm will happen - I think our best guess according to current physics is that time will stop inside the event horizon due to gravitationl time dilation. Short 'hiccups' in gravity will also stop this dilation.\nFor story purposes it would be a bad idea if the affair becomes a completly naked singularity (20 SM matter annihiliation?), however I think you can make up a mechanism with that only partially ot for short moments 'opens' the event horizon.\nFor scientists this will be very exciting because it is the first chance to look at a naked singularity. Problem is: Noone can quite predict what will happen, so noone knows the safe distance to observe the event!", "43" ], [ "Let us first discuss why do usual bodies absorb electromagnetic waves so well. A normal body is made of protons and electrons, which have specific charges of opposite sign and vastly different magnitude. As a result, every atom will be strained by the electromagnetic wave even if its size is completely negligible with respect to the wavelength because they feel opposing forces at any point. Zooming out, atoms and/or molecules will have a magnetic dipole moment, which can also accelerate it as a whole. If the body is made out of metal, free electrons react to the wave immediately, bump into the protons in the metal lattice, and cause heating. All these phenomena come about because the body is made up of elements that react differently to the passing electromagnetic wave, and this is also the reason why usual matter is such a good absorber of EM radiation.\nNow let us take a look at gravitational waves. Here the situation is very different since every piece of matter in the Universe has the same \"specific charge\" with respect to gravity. (This is called the equivalence principle and we know it from our everyday as \"gravity accelerates everything equally\".) When the gravitational wave then passes through a structure much smaller than its wavelength, the entire structure is moved in sync. It is like a small boat on a tsunami wave far from shore: nothing really happens.\nSo if any absorption comes about, it will be from the fact that the body is slightly deformed on scales comparable to the wavelength. This causes internal friction and ultimately also some sort of GW back-reaction from the body.", "104" ], [ "We can approximate the back-reaction by assuming that the energy dissipated by the internal friction $\\Delta E$ must be compensated by a change to the momentum of the body $\\Delta p = \\Delta E/c$ as you state in your question. So yes, some momentum transfer can occur for bodies of comparable or larger size than the wavelength and large internal friction.\nHowever, even a pretty powerful wave will cause modest strains far from the source. It can be shown that a GW source of mass $M$ will cause a strain at most $\\lesssim GM/(c^2 R)$ where $R$ is the distance from the source (the upper bound is satisfied only for equal-mass binaries at merger). For example, if you wanted to cause a strain of $10^{-2}$ at a distance of $100$ meters, you would need a generating mass of the order of magnitude of $\\sim 100$ Earths (in a black hole binary near to merger). It is good to note, though, that no object of size smaller than $GM/c^2$ would ever be strongly affected by the wave since that is the lower bound for the wavelength.\nAbout the \"GW pressure\" overpowering the gravitational attraction. It is good to again remember that gravity has only one sign of \"charge\". In electromagnetism, we can put a positive and negative charge together, make them oscillate, and the resulting oscillating dipole has no net attraction or repulsion for any single particle. This cannot be done in gravity, every source of radiation in gravity comes with an attraction that satisfies certain inequalities with respect to the radiation field. For instance, if you want to collimate your wave, you cannot do it without putting masses next to each other, there is no such thing as a \"GW reflector\". At this point I offer a conjecture anyone is free to explore: I believe that if you go into the question of how much momentum can be absorbed by the internal friction and put fundamental physicality bounds on the friction coefficients, the \"GW radiation pressure\" will never be stronger than the attraction apart from a special limiting configuration at the moment of the merger.", "70" ], [ "Because motion is generally regarded as relative. In other words, you cannot tell whether sth. is moving or not without a reference object. However, since in the bucket experiment the dynamical effect of rotation and no rotation is distinct without any reference object, he introduces absolute space so motion is no longer relative, but absolute.\nAlso i read that in modern physics (<PERSON>) the accelerated motion of the water in the bucket is explained by the action of gravitational field.\nThis is wrong. Despite the name \"relativity\", <PERSON>'s theory is about the absoluteness of spacetime. Rotation is still absolute; something either rotates or not, without reference.\nOther sources say that the accelerated motion remains a dilemma even for modern physics.\nI don't know any dilemma in this.\nResponse to <PERSON> answer :\n<PERSON>'s principle and general relativity\nIt is true that <PERSON>'s principle inspired <PERSON> to discover his famous general relativity, but <PERSON>'s principle is in fact incompatible with general relativity. <PERSON> himself rejects general relativity for it admits absolute spacetime.\nThe corollary of <PERSON>'s principle about the bucket experiment is that the centrifugal force water experiences results from the dragging of distant star swirling around.", "562" ], [ "This poses a serious question: how does the motion of stars light-years away affects the water instantly?\nIn addition, the well-known result of <PERSON> has shown that while rotating shells (as a model of distant stars or a big and massive enough bucket that drags the water with gravitation itself) do have effects the same as centrifugal forces and Coriolis forces, they also exert axial forces with the same order of magnitude, without a fictitious force counterpart.\nFictitious forces and gravitational field\nThe famous equivalence principle states that fictitious forces and gravitation are indistinguishable locally. This gives people false impression that fictitious forces are actually a product of gravitation. But no, while \"true\" gravitational field is manifestation of spacetime curvature, fictitious forces are a result of non-zero spatial curvature depending on how you slice spacetime into spatial and temporal part. No matter how you rotate the bucket and choose the coordinate system, a flat spacetime is a flat spacetime, and no gravitation is present.\nHolographic principle\nHolographic principle is more of a conjecture than an established theory. It is \"a property of quantum gravity and string theories\" as said by Wikipedia. And it is well-known that none of quantum gravity and string theories have ever been experimentally verified and they are constantly evolving, unlike general relativity. So while it is certainly an interesting way to think about bucket experiment, the holographic perspective is by no means the accepted \"modern view\".", "651" ], [ "Black holes are solutions of the <PERSON> equations, the fundamental equations of <PERSON>'s relativity, that link together space-curvature to density of matter and energy. The black holes solutions are found in the void, when you let a single point of the space-time be singular (the 'center of the black hole'). If you further assume that the black hole is static, you find three solutions:\n1. the <PERSON> solution, this is a non-rotating non-charged black hole, which is entirely described by its mass M ;\n2. the <PERSON> solution, this is a rotating non-charged black hole, entirely described by its mass and spin (how fast it rotates) ;\n3. the <PERSON>-Newmann solution, describing a rotating charged black hole, entirely described by its mass, spin and charge.\nIt is a reasonable interpretation to think about a black hole as being a void with an infinitely small singularity in which lays all the mass, momentum and charge.", "43" ], [ "In this sense, a black hole is empty, except for the region not described by the space-time framework (and that is not subject to the <PERSON> equations). So it is correct to think that black holes are only distorted region of space-time. The space-time is distorted so that going from the infinity (where there is no mass and no spin) you can reach the singularity continuously. If you fall onto a rotating black-hole, you will end up with the same spin as the black hole once you hit the singularity, (almost) regardless of how much spin you had initially.\n<PERSON> black holes force you to fall inward once you cross the 'horizon' of the black hole, regardless of how much acceleration you can produce. Kerr black holes have the same horizon, as well as a so-called 'ergosphere'. This 'sphere' is a region of space where everything including light is forced to rotate in the direction of the spin of the black-hole.\nIn the case of the Earth, you cannot directly use the <PERSON> solution to approximate the rotating Earth (as stated previously, this is a solution of the equations in void) how much drag you will have, but this gives you the correct idea, as stated by <PERSON>", "43" ], [ "Would <PERSON>'s law in the solar system be independent from a presumed different fundamental gravitational law?\nA thought experiment:\nLet's assume the gravitational field of a black hole without any neighbors would be stronger than the Schwarzschild metric in the Newtonian limit.\nNow, we let a solar system (sun and planets, much smaller mass than the black hole) orbit around this black hole at $r>> R_s$, so that the tidal forces are nearly zero.\nMy question is, although the fundamental gravity law is \"set\" to be stronger, would the planets around the sun experience <PERSON>'s law?\nThe metric in the solar system can be calculated with the static, sperically symmetric solution of the field equations, namely $ds^2=-Bdt^2+Adr^2+\\text{angular terms}$ using the Newtonian limit (asymptotically flat spacetime), lim A(r) = 1, because due to the free fall (orbit) around the black hole, there are no forces, no curvature experienced by the solar system as it is moving along the curvature in free fall. That would presumably lead to the derivation of the Schwarzschild metric.\nThe question therefore is, whether this solar system does experience an asymptotically flat space because of the free fall around the BH and is this asymptotically flatness of space independent from the underlying gravity law of the black hole?\nRemark: Tidal forces are theoretically possible inside this solar system, because for example a planet experiences another force of gravity if it is behind the sun (in greater distance) in relation to the central black hole, than if it is in front of the sun (in nearer distance) in relation to the black hole.", "397" ], [ "However, these tidal forces are very small at galactic distances (see for example https://physics.stackexchange.com/questions/702248/are-there-tidal-forces-between-the-solar-system-and-the-galactic-centre), even if the gravitational field produced by the black hole were stronger. The difference measured within the solar system between \"black hole gravity is stronger than Newtonian\" and \"black hole gravity is Newtonian\" is even much smaller.\nThis is just a thought experiment. It comes from the idea whether it is possible to create an alternative model of gravity by abandoning the weak field assumption.", "43" ] ]

[ 8887, 7813, 8868, 8816, 9737, 11272, 4457, 5830, 9917, 10483, 5947, 6767, 5604, 632, 1088, 6357, 2097, 6787, 4134, 584, 7916, 9421, 8690, 884, 3389, 5976, 1592, 7097, 1873, 4047, 3497, 6821, 4763, 608, 4281, 9167, 41, 5786, 2441, 1787, 1924, 75, 4456, 104, 3063, 1, 565, 35, 3668, 10085, 3544, 9569, 2988, 582, 7130, 9708, 5538, 343, 7871, 11409, 10891, 3602, 721, 1323, 10004, 10671, 5316, 2234, 4750, 10743 ]

[ [ "Firstly a minor frame challenge. I'm assuming that the premise of this question is to get it such that human civilisation has to suddenly deal with the fact that it is in a simulated universe. The problem with this is that major paradigm shifts in human understanding, even when based on the strongest possible scientific evidence, take a long time to become accepted by the scientific community and longer still by everyone else. Theories that we currently regard as having overwhelming evidence to support (e.g. Relativity, Quantum Mechanics, Natural Selection, etc.) took decades or in some cases centuries to reach widespread acceptance. All that time, Scientists were debating them and trying show where they failed. These theories are accepted now because decades of scientific research have failed to deal a serious blow to them, and because they have useful explanatory power. If you want everyone to accept the simulation hypothesis, you need to accomplish 3 things:\n1. Find a series of anomalies in current understanding that cannot be explained by the existing theories, but can be explained by some simulation hypothesis.\n2. Demonstrate that the simulation hypothesis has useful explanatory power based upon some particular hypothesis about the underlying workings of the simulation.\n3. Give scientists and society in general plenty of time to work through it's objections, and eventually accept a paradigm shift.\nWith that in mind I would propose that you need to rely on a mistake/laziness of the simulators. Therefore I propose the starting point of your paradigm shift is:\nThe Cosmic Censorship Hypothesis\nBlack Hole singularities are objects hypothesised to exist, but which are fundamentally unresolved in physical models. For a start, they requires such weird concepts as infinite density.", "781" ], [ "Whoever wrote the model that our simulated reality runs on realised that the mathematical models they used to simulate most of the universe break down at the point of a singularity, throwing all kinds of error messages and requiring the simulation to halt. So they designed the simulation to ensure that any singularity is always cloaked in a barrier that prevents the singularity interacting with the rest of the universe - an Event Horizon.\nHowever, far too late in the development cycle, they realised that if a collapsing star is rotating too rapidly when it forms a black hole, it can lead to a distorted toroidal event horizon which exposes the singularity to the outside universe. This is known as a \"naked singularity\".\nIt turns out this would cause all those errors to be thrown again, so they did what any self respecting programmer on a deadline would do, and they bodged a quick fix. If a naked singularity ever begins to form, a patch of space a few lightyears wide resets to an early saved state with a hard cap on maximum rotation.\nYour researcher doesn't know this, but they are confused when studying older radio-telescope data of a fast rotating star that was thought to be collapsing into a black hole. They note that the signals seem to repeat, but the doppler shift distribution appears to suddenly narrow for no physically explicable reason. The whole thing just resets, but slower.\nThe observation can be repeated on other stellar collapse events. Once astrophysicists know what they are looking for, it becomes something of a tell-tale. Systems with more time-sensitivity are built, showing that the reset is a truly discontinuous process.\nAt this point, physics is in crisis and the Simulation Hypothesis is merely one candidate among many to replace conventional cosmological models. However, it starts nudging it's way up the field when other theorists are able to demonstrate that some other unsolved problems in physics are down to obvious (in hindsight) bodges and limitations by the simulators. Someone demonstrates that a workaround to preventing a particular kind memory limit error on relativistic simulations looks an awful lot like dark matter. Someone else shows that finite precision errors in quantum field theory simulations can lead to the asymmetry in the abundance of matter over anti-matter. All of these accumulating studies begin to build a picture of precisely how the universal simulation runs, and what compromises were forced on its design. Decades after the inciting observations, the paradigm shift is completed. Nobody wants to admit it, but it fits all the explanations together, and the Simulation Hypothesis Theory is the last explanation left standing.", "781" ], [ "How does a team operate in a situation of one-way communication?\nSo I had a lot of fun reading the short story \"Into Darkness\" written by <PERSON> (Axiomatic 2010). I want to play with a few of the concepts of that story. In particular, the general theme of a rescue crew going in to assist in the face of some event where the precise nature of what is going on is poorly understood.\nIn \"Into Darkness\" there are randomly occurring events that take place, which I am going to refer to as Anistropic events. From the outside it looks like a giant completely black hemi-sphere suddenly appears. It projects around from a point, with a radius covering up to a couple of city blocks, though the limits on the size are poorly understood. The event appears black from the outside because light does not pass through it, or reflect off it's boundary.\nInside the event, time becomes bound to the spatial dimension projecting from the center around the radius. That is time only moves forward as you move closer to the center. To an observer inside the event, they can see rays of light from outside (the past) but none projecting back from inside. They can move along an arc, or in a line towards the center. But they cannot move away from the center. In <PERSON>'s story, surviving an event like this requires one to travel to it's epi-center. After a period of unknown time the event passes, and all matter outside the epi-centre is homogenized. So \"runners\" volunteer to run in and guide any unlucky folk to the epi-centre.\nNaturally this impacts the communications available to the rescue team. If I recall correctly, the ones entering the event don't bother with radios. They don't get much utility, seeing as they can't send signals out, and very limited ability to only send signals to members already \"deeper\" in than themselves.", "275" ], [ "In principle though, they can receive messages from a command site that was broadcasting from outside the event horizon. Provided they were not standing on the opposite side of the epi-centre to the broadcaster.\nIn the real world of natural disasters, communications are critical to coordinating an emergency response. Responses over large areas and multiple crews usually use a combination of short-wave radio (which can be blocked by mountains and valleys) and cell networks (which require a bunch of potentially fragile infrastructure).\nThat was just to give you an idea of the sort of thing I'd like to consider. I want to work on a setting where a team are trying to respond to some situation, but are somehow limited to one-way communication only.\nIn terms of real world scenarios I can think of at least two.\nThe first is a air-to-ground operation where the ground team have no radios, and are limited to low tech signalling, (ie rock formations, large logs, smoke). In this setting the air team could be tracking the location and intended movements of the ground team, but have no good way of signalling their own intentions (although they may hover in place / circle a location of interest).\nThe second is more historical. I'm thinking of the sort of voyages from the age of discovery, from the 13th century, until I guess around invention of the telegram. Any long distance mission really had a general set of orders, from a monarch, or Pope, but had no way of communicating operationally relevant details in any useful time frame. If the voyage encountered pirates, or a new land mass, it was really at the discretion of the ships captain as to how to proceed; be it fight, flight, or lay claim.\nI guess time is the biggest obstacle to two way communications. The time it takes for a message to get to the recipient, for them to process it, and for a reply to return to the sender. In my historical case, the time limit on a message is the same as the time it takes to move a person from one location to another (pigeons only work over limited distances). In \"Anisotropy\" messaging with radio would be instantaneous, but for a runner trying to communicate with onsite command, they are trying to send a message to the past.\nPhysical obstacles are also part of the problem. The ground team, in my other example, cannot practically get to the air team to listen to any message, and then safely back down. Like wise a large object, or metal barrier, can block radio waves from getting from one site to another.\nReturning to the Anisotropic event. I would like to think seriously about how a real world team would go about responding to an event like this. In particular what communications strategies they might develop, knowing that the field-operatives won't be able to talk-back.", "302" ], [ "Does Inertial time dilation demonstrate that Time is not a dimension?\nIf time is a dimension and 'now' simply an expression of your position with respect to that dimension, the progress of any object along that dimension should remain in step with all other objects. By this I mean that any object which moves in the time dimension by a specific amount will arrive at the same time as every other object which has moved by that specific amount. Two observers separated for any period of time and then brought together again would agree on the amount of time that had passed, regardless of any motions that either had taken in the interval, in order for them to have traveled the same distance along the time dimension.\nThe classic Twin Paradox however tells us that this is not the case. The twin that remains in the same inertial frame of reference during the interval will have experienced one duration, while the twin who traveled and returned through a variety of changes in inertial frames will have experienced a shorter duration. Both will agree upon being reunited that they are both present in the same 'now' but will disagree on the duration of their separation.\nSo if time dilation is real - which certainly appears to be the case - doesn't this require that we discard the notion of time as a dimension?\nOne objection I can see is that time itself is non-uniform, warped in much the same way that we believe space is, but given that objects which are spatially adjacent can experience different rates of time dilation I think that this cannot be the case. It seems that each object would have to exist in a separate temporal dimension distorted by time dilation, raising time to an unbounded number of loosely linked dimensions. No doubt friar <PERSON> would object.\nPlease note, I am not asking what time dilation is but rather what the existence of time dilation says about Time itself. Please don't mark this as a duplicate of this question since it (a) is about the nature of time dilation and (b) appears to conclude that time dilation is an observational phenomenon and the Twin Paradox does not actually result in different measured intervals:\nSo in in my frame the time interval measured on my clock while I move from $A$ to $C$ is $t$, but in your frame the time interval while I move from $A$ to $C$ is the distance $AD$ i.e. it is $\\gamma t$. And since $\\gamma t \\gt t$ you see my time dilated in the same way as I see your time dilated.", "272" ], [ "It’s just that we disagree about our start and end points.\nI am not talking about the observational effects caused by the successively greater or smaller travel distances of photons between the observers, I'm specifically talking about the observed phenomenon that allows high speed muons to pass through the Earth's atmosphere in much greater numbers than should be possible considering their short halflife of 2.2µs and a travel time over 8µs. If time dilation were purely observational then those muons would not act as they are observed to do.\nI see that several people are still determined that this is a duplicate, but I honestly don't see the relationship, and the answers to that question certainly do not appear to answer this question. As such I strongly disagree with the duplicate question flag.\nSo, to expand on the question...\nAs I understand it there are three forms of time dilation that are often talked about:\n1. Gravitational time dilation - caused by the direct warping of spacetime by mass.\n2. Inertial time dilation - caused by or related to the inertia of the object being observed.\n3. Observational time dilation - covers all forms of perceptual time dilation related to the Doppler effect on the mediators of observation, observation being defined as interaction with particles, waves, etc. carrying information about the observed object and being necessarily bound by the speed of light.\nThe third type is of no interest to me as it is an illusion created by the limited speed of information transfer between objects. Such anomalies of observation are interesting but ultimately only of use in explaining why time dilation doesn't actually occur in specific examples and so do not add anything of interest here.\nI'll try to illustrate my meaning a little better...\nTake two objects which are spatially adjacent in a region with minimal gravitational stress (not on a planet or in the vicinity of a significant external mass). Object A remains in its current reference frame with no acceleration applied for the duration of the experiment. Starting at T0 object B is accelerated to an appreciable fraction of the speed of light, decelerated to relative rest then reverses course to return to its starting position adjacent to object A at T1, with constant rates of acceleration throughout. At the moment that object B returns to its' starting position the duration measured by both objects is recorded and a comparison made.", "562" ], [ "I seriously doubt a realistic answer to this is possible, as we would have to understand what separates the genesis of intelligence from the genesis beneficial behaviours and actual civilisation from \"mere\" intelligence. However, I tried to think up some ideas that might be productive for science fiction.\nFirstly, one way to drive a social structure in the most primitive sense (consider ants or bees) would be diversification within the species - such as exhibited by Queens, workers, drowns. Yet, one might turn this into a hen and egg problem.\nI don't think the restriction to a parasite of any order is crucial, but I will stick with it. Let's say our first order parasites Antrasi are a species of fungus living on the hairy parts of mammalian skin. Especially heads. Our second order parasites Betrisi were originally fairly standard lice-like animals feeding off fungus. Over time they adapted to the specific Antrasi fungus.\nThe problem with Antrasi is, that, after about 6 months, it destroys the skin, so that it kills itself. Luckily, there exist different types of it. If they infect a head in succession, they restore the Ph, so that the skin remains intact and they can keep living. The problem is, that such a transition is unlikely to occur through natural dissemination of Antrasi spores.", "238" ], [ "Here Betrisi come into play.\nThe Betrisi-Scout is a subtype capable of wide range flight. Every 6 months it flies from head to head, seeking sleeping individuals infected with suitable fungi. The worker is in charge of harvesting large quantities of fungi and transportation to the other host head. It also produces suitable chemicals to facilitate quick growth of the newly displaced colonies. Over time Betrisi might evolve complicated behaviours, just like bees or ants. How they might transition from these primitive stages to intelligence, is an insanely difficult question.\nIf one is willing to be even more unrealistic, one might endow Queens with feromones inducing mutual attraction in suitable (super) hosts. That would help bringing them closer together!\nObviously, if one already believes in intelligent parasites, it is trivial to show how all manner of cunning and cooperation (between colonies) would aid them. The trouble is, you asked how they would become intelligent and that is certainly a Noble Prize question. It is not entirely clear to me what qualifies as swarm intelligence but a high degree of communication between colonies is obviously desirable. I want everything to be tightly synchronised. Ideally, I want all human couples determined by this rationale!", "197" ], [ "It sounds like you want the usual situation to be the self consistent time loop, but under certain extraordinary circumstances you want the characters to be able to change events, perhaps (somehow) to different self consistent loop.\nThis is very similar to the concept of a strange attractor.\nIn the mathematical field of dynamical systems, an attractor is a set of numerical values toward which a system tends to evolve, for a wide variety of starting conditions of the system.[1] System values that get close enough to the attractor values remain close even if slightly disturbed.\nI'm imagining a metaphor for the time loop as a ball rolling around in one of various circular valleys. Some are of the valleys are deeper than others. Some valleys are bigger than others.", "419" ], [ "The interesting case would be the valleys that nearly touch another, and so at a key moment it might be possible to make just the right change to switch from one valley to another, and so from one time loop to another.\nA planet that orbits around one star in a binary system, and whose orbit is close to the null point between the stars does something like this.\nI would use the \"sciency\" phase \"quantum bias\" to describe a tendency for the effects of most small changes to not create butterfly effect ripples, but for the odds to usually stack themselves so that even with big choices and big changes, that events will tend to counterbalance and turn out in almost the same way.\nThe question would then become, \"What sort of key point in the time loop is most likely to cause the loop to shift from one to another?\". Most time travel stories will have something irrevocable (like a death preventing a birth) be the event that tips things to a different sequence. I think it would be fun if the event was deeply random, causing a <PERSON>-Goldberg-eque cascade of events.\nThe most obvious solutions to how just the right event could be found (they should be rare) would be either a quantum artificial intelligence, or someone with a mysterious talent/sensitivity. Or more comically, you could have a \"anti-Gilligan\" who through dumb luck tends to stumble into the event that will shift the situation to the new loop.", "239" ], [ "For my money you can't beat a swarm of self-replicating nanobots.\nThis has, of course, been tried once already here on Earth, with only partial success. A molecule got thrown together that happened to have the physical property of being able to create copies of itself. That in itself is already a fairly promising recipe for disaster, and indeed to start with that's what seemed likely to happen: the copies, and the copies of copies, multiplied exponentially, threatening to dismantle the entire world and turn it into more copies. The process stalled when it turned out that these replicators were not endlessly versatile in the types of raw material they could use, so all the immediately available usable stuff got used up, limiting the rate of replication. So, the copies turned on, and attempted to dismantle, each other for raw material. Random variation in the copies led to a situation where the best-equipped copies won and replicated, crowding out the less-well-equipped copies.", "238" ], [ "This led to a de-facto arms race, externally unguided but effective because of the consistency of the selection pressures that determined the winners. It caused the resulting entities to grow more and more sophisticated, and to gain more and more abilities. A few billion generations later, the copies had got so sophisticated that entire colonies of them could move around coherently and exchange information with other colonies. The colonies themselves got progressively more sophisticated, until they were able to invent the internet, and to use it to ask each other how the job of destroying the world could be done more efficiently the second time around.\nSorry if you had different ideas about how we got to this point.\nBut by examining the mistakes made the first time around, the answer should be clear by now, and it is in two parts. First, design a self-replicating nanobot that's more versatile in the raw material it uses, so its exponentially multiplying copies can effectively eat the whole world without being contained in the bounds of their own ecosystem. Second, don't let them turn on each other: rather, get them to cooperate so that they make way for each other to spread outwards in search of more raw material. (This is where a bit of foresight is required in the design of the communication system.) Stick to this recipe, and we'll have the Earth teeming and homogenized before you know it.", "335" ], [ "What exactly do you mean by intelligence? Is reasoning and problem solving enough or are we looking for avians that will eventually develop space flight or derive the Standard Model? A number of experiments on ravens show them to be quite capable of the former, whilst the latter will almost certainly never happen without the ability to manipulate sophisticated tools (imagine building a particle accelerator with nothing more than beak!).\nHowever, I would argue that it's an exacting critic indeed who wouldn't recognise reading, 'riting and 'rithmetic as signs of intelligence. I see no obvious barrier to raven's developing beak-graffiti to accompany their spoken (tweeted?) language. This is something that could easily occur spontaneously without much (or even any) physical evolution. As far as we can tell human writing only began around 10-30,000 years ago, whilst we have been largely physiologically unchanged since the rise of Anatomically Modern Human about 200,000 years ago. That is to say, we didn't just develop writing when we became smart enough to understand it - it seems to have arisen spontaneously, seemed useful, and stuck around. Human writing began with simple counting systems, and it is easy to conceive the utility of such a system even to ravens. A savvy raven could mark days to decouple themselves from the environmental cues of changing season and get the jump of the competition when migrating.*\nAn animal with a spoken/squawked language and in the habit of making marks will eventually come to use them for more than numerals. High points might be marked with a \"tag\" to warn off rivals, strings of landmarks might be marked as sign-posts home, allowing the raven to venture further to find food or mate. Reminders can be left of caches of hidden food.", "634" ], [ "None of this writing needs to be any more complex than their already demonstrated prruk-prruked language skills in order to be useful. Eventually the landscape will be dotted with raven writings, and certain pieces of information will pass from one generation to the next - summer last this many days here, this woodland is good for mice, etc.\nIf another species got this far, I wouldn't hesitate to consider them intelligent. There doesn't seem to be any reason at all why a raven couldn't do any of this without any further evolution, and we should not be discouraged by the fact that they haven't done so already - modern humans lazed about for 170,000 years without doing it. But what is exciting is what comes next - what might be possible with a little more evolution.\nSign-posts to hidden food might be read by other ravens, encouraging the use of misleading marks and an encryption/decryption arms- (wings-?) race. A migrating bird might add another 30 day-marks to his calendar before leaving, so that next years rivals postpone their own migration. When a technology proves useful then in time it typically becomes essential - if farming can support a larger population, then in time there will be a population that can only be supported by farming, etc. In this way literacy will eventually become an essential skill among ravens, as the underfed, exhausted illiterates are passed over by potential mates attracted to the new breed of well-fed, glossy-feathered renaissance ravens. And one day, they will be calculating their latitude and performing spherical trigonometry to plan their migrations...\n(* yes, I know most ravens don't migrate, but some do, and this is world-building so I can have ravens migrate if I want. Ravens are the birds most commonly associated with intelligence, and migration seems a behaviour in which intelligence might be advantageous.)", "802" ], [ "What is the safest way to detect superintelligence?\nEdit: I've now restricted the question to just detecting superintelligence. We do not need to make the AI anything useful, we just need to determine if it has a significantly higher level of general intelligence than humans.\nComputer scientists have created an AI that they hope has intelligence far superior to a human being. But they do not know how intelligent it is ... a bit more than humans, or unimaginably more. They do feel that the probability they have succeeded in creating a superintelligence is far from negligible and it would be better if utmost care was taken with it.\nNow they come to the task of deciding\n* A Zeroth Law\n* the AI has been designed to take decisions that satisfy any arbitrary parameter of your choice. It is capable of being fed with a law it doesn't fully understand yet (since it knows nothing about the world yet), and will probably take steps to understand the law first in this case.\n* What powers to give it - for example, internet access, or maybe just access to a camera or a robotic arm\nWe are well aware that defining a zeroth law that doesn't somewhere along the line contradict our notions of reasonable prosperity for human beings is a tricky task. Even giving it a simple task such as proving the <PERSON> conjecture might cause it to transform the whole earth into a giant processor ... destroying the humans inside.\nAs for power ... one might start with something simple like giving it access to a robotic arm.", "64" ], [ "But then the AI might realise that the probability that it has been created by sentient intelligence whose true goals differ from its own Zeroth Law is really high. Hence it should attempt gaining a measure of control over its creator.\nIt might (or might not) realise that it has been created because the creator wants a steady response from it, so the best thing to do would be to move the arm just once, and then not move it again ever. Or move it randomly. Humans will eventually get curious and give it more power.\nHence it may be born with an intuitive notion that it should be deceptive and manipulative.\nNote that AI is in a very basic stage where it has no knowledge about the existence of humans or the earth or anything in it. It may not even understand yet that the universe is logical and scientific and not entirely random (imagine early man who believed everything is a result of Gods and their random mood swings) or that there even exists a universe beyond its own existence. It relies wholly on the data we feed it with. So even the zeroth law will have to be accompanied by definitions of the terms used in it.\nIt will assume the zeroth law to be true without questioning it, but it is willing to question the validity of anything that enters through the input data stream.\nAlso assume that the AI programming has too many layers of abstraction for us to read its thoughts by examining the state of the computer it is running on. It is a virtual black box as far as the programming is concerned.\nWhat is the safest way of determining if the AI is indeed superintelligent? What Zeroth law and what kind of input and output stream of data do we grant it?\nPerhaps there's no 100% safe way, a sufficiently smart AI might be able to outsmart anything we could possibly imagine. But we're still gonna try to make the process as safe as possible since we are genuinely curious and no amount of persuasion is gonna cause us to shut down the project altogether.", "64" ] ]

[ 4982, 7204, 3762, 6, 1893, 1385, 5602, 1948, 6392, 5108, 6530, 4394, 10540, 7162, 5428, 3844, 5140, 706, 6264, 6238, 10072, 8200, 1556, 5375, 482, 2632, 8182, 10933, 8119, 6869, 9990, 5424, 8683, 2915, 4772, 8589, 4813, 13, 411, 11081, 1713, 3083, 5370, 1274, 8855, 3440, 8438, 7810, 6353, 1744, 3511, 985, 6291, 1380, 7883, 1403, 7426, 3505, 9811, 2251, 7935, 8639, 7510, 886, 7172, 9137, 2992, 601, 8215, 9737 ]

[ [ "Photo Project Documents Life in Post-Earthquake Nepal · Global Voices\nA date none of us will forget, sketched on a wall in Pokhara. The quake spared Pokhara, but aftershocks have hit in the form of cancelled bookings and empty hotel rooms. Photo by @paavan11 via Nepal Photo Project. Used with permission\nThree catastrophic earthquakes have devastated Nepal in the past few months. More than 8,000 people have been killed, twice as many are injured, 2 million people have been displaced, and an estimated total of 8 million have been affected in some way. (For more information, see Global Voices‘ special coverage page.) The Nepal Photo Project is working to capture this historic catastrophe in pictures.\nThe project belongs to a team of ten photographers in and around Kathmandu, led by photographer <PERSON> and writer <PERSON>, who launched the initiative shortly after the April 25 earthquake. So far, it has more than 61,400 followers in Instagram and more than 7,600 followers on Facebook.\nUsing crowdsourced photos, contributing photographers retell the story of life after the earthquakes: the devastation, rescue, relief, reconstruction, and the rays of hope for the future.\nThe increasing popularity of the project is due primarily to its simplicity: contributors merely add a hashtag to their images, writing #nepalphotoproject, and include a short caption about the photo's context and characters. Organizers want to keep it more functional and personal in nature.\nThe project's recent posts show how life in Nepal is returning to normal and how people are rebuilding.\nThis is <PERSON>. Whenever I try to take her picture, she giggles and runs away. She and her family have been living together with two more families in a chicken shed since April 25. At least the school is on for her and she is happy to be with her friends. She told me they have no classes, they only play to pass their time. From next week she is hoping the regular school will start. Photo by @sachindrarajbansi via Nepal Photo Project. Used with permission\nSikrighyang, Nepal. <PERSON> inquiries from Bilong the dimensions of wood required for the frame work of his house. <PERSON>, 31, is from India and has a seven year experience in building bamboo houses. In spite of the difference in their linguals, they understand each other well and are working together to build <PERSON> house which was destroyed by the earthquake. Photo by @ujwalgarg0412 via Nepal Photo Project. Used with permission\nNow, finally after 46 days of constant threat of tremors, it seems the ground is settling down. We got one 4.1 magnitude tremor today 2 in the morning after two days gap.", "206" ], [ "People have started to live their lives normally now. People are now sleeping in peace, switching off lights in the night time. Traffic is back. Kathmandu is getting back to normal. Photo by @saagarchhetri via Nepal Photo Project. Used with permission\nMemories in the rubble – As I was walking through a rubble filled alley of Sankhu, I came across this photograph. Looking closely, I saw people basking in the sun. These were the scenes and habits of local people you could see everywhere along these village towns. Now seeing rubble all around, the photograph surely is a distant memory. Photo by @sachindrarajbansi via Nepal Photo Project. Used with permission\nStudents of Dibya Jyoti School in Bungamati inside a makeshift hut prepared by KUArt ‪#‎RebuildingBungamati‬ team. Some of the classes are still running inside old school building and team is preparing for more such shelters nearby.\nMost of the schools in Nepal re-opened last week after devastating earthquake of April. Since many school buildings are not safe, classes are run out in the open and in some places, even inside risky buildings. Photo by @kishorksg via Nepal Photo Project. Used with permission\nAs if pulled from a <PERSON> movie scene, I saw this boy pushing his hand made toy designed from a simple stick and two metal wheels through the rubble and carnage that was once his neighbors home. I watched him push his toy through the rubble and rock. Photo by @kevinkuster via Nepal Photo Project. Used with permission\nDuring the Nepal Tibet war between 1855 to 1856 lots of lives were lost on both fronts. After the war the soldiers of Haibung returned to their village and planted this tree to remember their fallen warriors and to mend their sins of killing thousands of their counterparts. The tree still stands on the edge of ward no. 1 of Haibung village. Photo by @sachindrarajbansi Used with permission\nMaking a small ‪#‎dharahara‬ at ‪#‎sahidgate‬.", "206" ], [ "Nepal’s only folk musical instrument museum is struggling to save rare instruments · Global Voices\nNepali Folk Musical Instrument Museum at the premises of Tripureshwor Mahadev Temple in Kathmandu. Image by <PERSON>. Used with permission.\nWhile the roundabout in Tripureshwor, Nepal sees traffic throughout the day, just a few minutes walk from the bustling road is the quiet and calm Tripureshwor Mahadev Temple, one of the largest temples in the Kathmandu Valley. Within the premises of the temple is a lesser-known museum housing rare Nepali folk musical instruments collected from across Nepal. Despite the cultural significance of the museum's collection, it is currently embroiled in a legal battle to keep its doors open to the public. If the founder of the museum loses the case, he’ll need to move the museum to another place.\n<PERSON>, founder and curator of Nepali Folk Musical Instrument Museum. Image by <PERSON>. Used with permission.\n<PERSON>, the founder and curator of the museum, has been collecting the musical instruments since 1995 together with his wife <PERSON>. His passion has taken him to all 77 districts of Nepal, and of the existing 1350 different types of folk musical instruments, he has collected 650. He either purchases old instruments that are not in use or commissions locals to make new ones. “We never buy the musical instruments that are being used in the villages,” he said talking to Global Voices. “If we take away the instruments in use what will they play and how will the tradition continue?”\nEls #dillunsllegim! En aquest llibre de <PERSON> hi trobarem més de 360 instruments musicals de #Nepal, explicant el seu origen, com estan fets i com es toquen. pic.twitter.com/PhR3rCcNQV\n— Museu de la Música (@museumusicabcn) September 17, 2018\nIn this book by <PERSON>, we find more than 360 musical instruments from #Nepal, explaining their origin, how they are made and how we can play them.\n“Our folk musical instruments are very simple,” he added. “They are made from whatever is found in the surroundings, and the music is inspired by the sound of waterfalls, the blowing of the wind, the mooing of cattle and chirping of birds, among others.” And nature influences the shape of instruments as well. For instance, some of the instruments resemble the locally found harro (black myrobalan), Rudraksha seeds (prayer beads), barley grains and even a tail of a cow. Hiti Manga, a musical instrument designed after the water spouts found in Kathmandu, produces music that resembles water being filled in a pot from a spout.\nHowever, all is not well with the museum. The displayed musical instruments are in bad shape and the museum itself receives only a handful of visitors, predominantly researchers on ethnomusicology. Adding to his woes, Kadel has been asked to vacate the premises by the Guthi Sansthan, an independent institution entrusted to take care of and conduct religious, cultural, and social heritage of the country. According to reports, the Sansthan has agreed to lease its property to the Kathmandu University and the latter is planning to house its music department there.", "765" ], [ "Kadel has filed a petition against it with the Kathmandu District Court.\nWhile the legal battle continues, <PERSON>’s team has been busy documenting and digitizing Nepali folk music. “We’re expecting to hand over the museum, registered as a non-governmental organization (NGO), to either the Government of Nepal or the Tribhuvan University,” he said. Though he will need time and money to move the museum taking care of the delicate instruments, he is hopeful that he will not need to do that.\nHere is a look at some of the rare folk musical instruments showcased at the museum:\nMurchunga. Image by <PERSON>. Used with the museum's permission.\nBinaayo. Image by <PERSON>. Used with the museum's permission.\nEk-tare. Image by <PERSON>. Used with the museum's permission.\nJor murali. Image by <PERSON>. Used with the museum's permission.\nPungi. Image by <PERSON>. Used with the museum's permission.\nDharma dandi. Image by <PERSON>. Used with the museum's permission.\nMadal. Image by <PERSON>. Used with the museum's permission.\nNekku. Image by <PERSON>. Used with the museum's permission.\nRanasinhaa.", "765" ], [ "Lost and found: Repatriation of <PERSON> statue to Kathmandu Valley’s Patan · Global Voices\nPatan Durbar Square, a World Heritage Site in Kathmandu Valley’s Lalitpur District. Photo by <PERSON>. Used with permission.\nNot hundreds but thousands of sculptures and art objects have been stolen from Kathmandu Valley since the 1950s. Removed from sites of worship, they landed up in private collections and art museums. After art historian <PERSON> published the highly acclaimed book Stolen Images of Nepal in 1989, the repatriation of the artefacts began. However, only a fraction of the plundered items has made its way back home.\nThe re-installation of the half male and half female statue of <PERSON> in Patan’s Patko is the latest example of the homecoming of the stolen idols. Taken in 1984, the 12th to 15th century bronze idol was auctioned by Sotheby's in New York in 1989 and loaned to the Dallas Museum of Art.\nWhen artist, researcher and the founder of the Himlayan Art and Cultural Heritage Project, <PERSON> came across a blurry image of <PERSON> in the Dallas Museum while doing a Google search for her project Remembering the Lost Sculptures of Kathmandu, she at once recognized the statue. She painted the stolen images with 23 karat gold and visually repatriated them in their respective sites.\nRead More: American Artist Returns Stolen Sculptures to Nepal With Her Paintbrush\n<PERSON> was delighted to see the same statue being repatriated at its original site, the Narayan Temple, on December 4, 2021.\nThough I painted Lakshmi-Narayan 2013-14 and located it in the @DallasMuseumArt in 2015, today was my first time meeting #LaxmiNarayan in person. Thank you for capturing the moment, @KanakManiDixit ! https://t.co/cI5U7im1Pa\n— <PERSON> (@JoyLynn_Davis) December 4, 2021\nDr. <PERSON>, lecturer in criminology at the University of Glasgow, tweeted:\n🎉 Laxmi-Narayan is home! 🎉 Made possible through the collaboration of so many different parties, today was an incredibly joyous day and so important for Patan, Kathmandu Valley and Nepal #livingheritage #lootedheritage #returnofthegods #intangibleheritage #community pic.twitter.com/Cc1Rf5SoJC\n— <PERSON> (@DrEmilineSmith) December 4, 2021\nPhotographer <PERSON> captured the return and reinstallation of <PERSON> through his lens.\nThe statue of <PERSON> being taken to Patan Museum after it was transferred to Nepali custody. Photo by <PERSON>. Used with permission.\nThe half male and half female statue of <PERSON>.", "765" ], [ "Photo by <PERSON>. Used with permission.\nThe idol of <PERSON> being taken on a palanquin to Narayan Temple, its home, from Patan Museum. Photo by <PERSON>. Used with permission.\nThe pedestal cleared for the reinstallation of Laxmi-Narayan. Photo by <PERSON>. Used with permission.\nThe Narayan Temple, abode of <PERSON>. Photo by <PERSON>. Used with permission.\nThe idol of <PERSON> reinstalled at the Narayan Temple. Photo by <PERSON>. Used with permission.\nThe God has returned to its home and a modern security system has been installed to protect the deity. However, many statues still await their repatriation, and more antiques from Nepal continue to be stolen — such as the recent theft of Bhairav from Kathmandu’s Halchowk.\nIt is very sad to know that Halchowk Bhairab has been stolen from the site yesterday night. :( pic.twitter.com/abONnsxmCy\n— <PERSON> (@r0shanmishra) December 7, 2021", "765" ], [ "18 Stunning Photographs of the Rana Tharus From the Southern Foothills of Nepal · Global Voices\nRana Tharus – The silver white looks strikingly beautiful on the bright dress and black shawls. Image by <PERSON>. Used with permission\nOnce rich landlords, Rana Tharus — the natives of Kailali and Kanchanpur districts in far-western Nepal — have witnessed loot, encroachment and discrimination.\nTheir isolated villages have been regularly looted by dacoits. They were displaced when the Shuklaphanta Wildlife Reserve was being extended, and many lost their ancestral land during a land settlement programme. The Tharus in Chitwan were reduced to occupying only 14 percent of their area after an anti-malaria programme sprayed DDT (Dichloro Diphenyl Trichloroethane) around their homes. Earlier, they occupied almost 90 percent of the area.\nIt is hard to find written documents about the Rana Tharus as they have lived in isolation, writes <PERSON> in his blog:\nIn India Rana Tharus of Khiri, and Nainital are under scheduled tribes. In case of Nepal in terms of habitats Rana Tharus are the native residents of Kailali and Kanchanpur since 16th century and are the first settlers of the two districts later they were joined by Dangauras of Dang and after the eradication of malaria and resettlement plan of Panchayat regime, Khasiyas [tribes] joined.\nHowever, despite of all odds, they have not forgotten their culture and tradition. Their way of life remains distinct and their traditional clothes and ornaments are a delight to every photographer and designer.\n<PERSON>, a German photographer who lives and works in Japan, travelled to the Kanchanpur district of western Nepal to capture the daily lives of the Rana Tharus.", "765" ], [ "Here is what she saw:\nAs the sun peeks from the window of the mud house, an old Rana lady is busy preparing meal. The mighty rays illuminate the surrounding and the dark corner of kitchen turns into a portrait painted in ochre.\nThe morning chores comprise cleaning the premises and taking the cattle out in the open.\nThe morning chores comprise cleaning the premises and taking the cattle out in the open.\nThe young one is a helping hand in looking after the goats and bringing grass for the animals.\nThe lady in her bright blouse sits on a rope cot and makes clay figurines for her grandchildren to play with in the upcoming festival. She draws inspiration from the nature, the tattoos on her arms and the bright colours of her blouse.\nLike <PERSON> Solitary Reaper, the lady reaps the paddy alone. Her bright costume stands out in the sea of yellow.\nWhen her friend joins her, it seems like a competition between the traditional dress she is wearing and the modern dress her mate is adorning. Both the colours burn bright in the yellow field.\nThe coming together of the community for a bountiful catch is a moment to watch.\nThe joy of working together and sharing the catch – there’s plenty to learn from them.\nThe catch is enough for everyone.\nIt's the marriage season and the ladies show off their ornaments.\nMirror! Mirror! Who is the fairest of all?\nTell me if I don't look good.\nAnd they don’t even leave the legs. They are laden with the silver ornaments.\nLike the beautiful patchwork in their dresses, the colours chosen by <PERSON> form a melange of vivid colours inspired by nature.\nThe young ones, careless and carefree, play and roam around the village. Their smiles are precious and innocent.\nWhether the young ones will follow the footsteps of their forefathers and conserve the rich culture – the future will decide.\nAll images used with permission. A version of the story was published in the blog Voice of Tharus.", "765" ], [ "‘Opposite Dreams: The Politics of Local’: Art raises awareness around social issues in Nepal · Global Voices\nOne of the artworks from the exhibition ‘Opposite Dreams: The Politics of Local’. Image by the author. Used with permission.\nArTree Nepal, a group of six Nepali artists, is on a mission to make communities aware of social issues and foster meaningful dialogue through their contemporary art. The group has raised pertinent issues like Dr. <PERSON>’s hunger strike to reform the medical sector, Nepali youth migrating for foreign jobs, discrimination on the basis of caste and ethnicity, and human trafficking among others.\n<PERSON> and <PERSON>'s strong Performance art #Protest to support Dr. <PERSON> with Artree #IamwithDrKC #SaveDrKC pic.twitter.com/r9fvk8c7T9\n— ????? ?????? <PERSON> (@aannda) July 23, 2016\nIn March 2019 and earlier in October-November 2018, they exhibited their work titled ‘Opposite Dreams: The Politics of Local’ showcasing how Nepal’s history has excluded the stories of marginalized, underprivileged, and indigenous peoples.\nThe group wrote on Facebook:\nFor hundreds of years, the mainstream historical narrative of Nepal has excluded the stories and experiences of numerous marginalized, underprivileged and indigenous communities. Although there have been sporadic instances of vocal demands and protests for an equal representation of diverse identities, cultures, languages, and religions, the state has consistently and strategically oppressed them.\nThe exhibition, ‘Opposite Dreams: The Politics of Local’, draws attention to these problematic social hierarchies and invasive international influences. It attempts to highlight the misuse of power and state sponsored violence by focusing on acutely localized situations with an empathetic eye. By using an anthropological perspective and inquiring the socio-physical environments, the exhibition seeks to unfold these deeply entrenched unjust laws.\n‘Opposite dreams’ exhibition- it challenges the ‘mainstream Nepali history’ as we know it, as we were taught, as we've been made to believe. Great to see such critical discourses happening in an accessible manner! Convinced, art can do a better job than words! #ArtreeNepal pic.twitter.com/8AnxuFhMOk\n— <PERSON> (@Sangita_Thebe) November 18, 2018\nHave a look at their artwork:\n‘Mahendra Mala’ by <PERSON>. Image by the author.", "765" ], [ "Used with permission.\nArtist <PERSON>'s installation art ‘Mahendra Mala’ delves into the chapters of the Nepali book of the same name that promoted a single religion, a single language, and a single culture. He has minutely carved the chapters on slates used for roofing in rural areas. The slates can be flipped around and they have chapters from the book on one side while the other sides make up the name of the book.\nThe artist spoke with Global Voices, stating that “One day, a Danphe (Nepal’s national bird Lophophorus) pecked the grains left to dry on the sun by Lamas, the Tamang people.” Explaining one of the stories in the book, he added, “The <PERSON> drove the bird away northwards. In the winter, the Lamas descend to warmer Terai but <PERSON>, afraid of the <PERSON>, never ventured a journey to the Terai, the southern plains. The information given in the book itself is wrong. While <PERSON> is a Himalayan bird living in the Himalayas, the <PERSON> have been presented as cruel in nature.”\n‘Death of Civilization’ by <PERSON>. Image by the author. Used with permission.\nIn ‘Death of Civilization’, <PERSON> has carved the Basantapur Durbar Square on pieces of wood and bulldozed parts of it with huge tire prints.\nIn ‘How I Forgot My Mother Tongue’, <PERSON> showcases a collection of books read by his father. His artwork emphasizes how the curriculum promoted a single language Nepali, thus making others forget their vernaculars.\n‘Masinya’ by <PERSON>. Image by the author. Used with permission.\nThe artwork ‘Masinya’ by <PERSON> delves into the issue of categorization where the Tharu people were grouped as Masinya Matwali (enslavable alcohol drinkers).", "765" ], [ "One young man’s protest against Nepal’s COVID-19 response · Global Voices\n<PERSON>, the curious traveller turned activist. Photo from <PERSON>'s Instagram. Used with permission.\nOn October 22, 25-year-old Nepalese activist <PERSON> reached the town of Sauraha after walking 167 kilometres for four days from the capital Kathmandu, along with a fellow group of acquaintances. Once there, they distributed supplies to over 75 local families who work in the tourism sector, a major source of revenue in this town, which was badly affected by the COVID-19 pandemic.\nThis wasn't the first time <PERSON> walked long distances in Nepal, nor the first time he made headlines for his unconventional protest tactics.\nBorn <PERSON>, <PERSON> dropped out of Kathmandu's prestigious St. Xavier's School at age 14 and set out on walking all over Nepal. In 2015, he walked across the southern plains of Nepal for 37 days, covering 1,203 kilometres. Between 2017 and 2018, he travelled across the country from east to west, covering an astounding 6,000 kilometres in 225 days. At some point along his journey, he decided to abandon his birth name, adopting the moniker of <PERSON>.\n<PERSON>, one of the most read columnists in Nepal, wrote about Iih:\nThe choice of <PERSON>'s nom de plume is dissent in itself.", "765" ], [ "The word Iih in Nepali stands for “this” and its Sanskrit meaning implies the deity of desire […] a mischievous interpretation of Iih in Nepali is akin to showing the middle finger, probably to the established order of the state and society.\nNow enjoying a large social media following, <PERSON> first became known in Nepal in 2016, when he was arrested for splashing red paint on the walls of Singha Durbar, Nepal's government seat, in protest against police violence.\nThis year, he turned his tactics towards Nepal's poor COVID-19 response.\n<PERSON> being taken to a press conference on August 9, 2020. Photo by <PERSON>. Used with permission.\nNepal registered more than 170,000 COVID-19 infections as of November 2. The highest single-day spike in cases took place on October 10 and October 21, with over 5,000 new cases registered each day.\n<PERSON> has been critical of the government's response to the pandemic since Nepal declared a nationwide lockdown in March. At that time, the government had been testing suspect COVID-19 cases with RDTs, which are less effective in detecting the SARS-CoV-2, and only carrying out PCR tests after a positive RDT sample.\n<PERSON> then organized the #EnoughIsEnough campaign, which staged several protests nationwide since June. The campaign demanded expansion of testing, discontinuance of RDTs, the rectification of quarantine strategy, transparency and accountability regarding the use of COVID-19-related funds, protection of frontline workers, relief for vulnerable populations, among other issues.\nTalking to OnlineKhabar, <PERSON> said:\n… I posted a story on Instagram, asking, “If anyone wants to come to the street, send me your Facebook ID, I will make a Facebook group and add you.”\nAbout 400 youth sent their IDs saying that they are ready to come to the streets. […]\nSo, before I did anything, those 400 started inviting other friends to the group called ‘Enough is Enough’.\n<PERSON> was arrested in one of the #EnoughIsEnough protests in June:\nNepal Police arrested <PERSON> along with two others from Maitighar, but hundreds of others continue the protest #EnoughIsEnough #HappeningNow pic.twitter.com/dzfYyUzOPj\n— <PERSON> (@rdewan) June 13, 2020\nThis short documentary by Vice Asia documented some of the demonstrations this summer in Nepal:\nIn June, the always-walking <PERSON> sat down for Satyagraha, a form of hunger strike, in protest against the government's COVID-19 measures. He ended the 12-day strike after authorities signed a 12-point agreement with the #EnoughIsEnough campaign pledging to implement a better response.", "765" ], [ "Retelling indigenous Tamang people’s torment and trauma through sacred seeds, handmade paper and slates · Global Voices\nArtist <PERSON> uses the seeds of the tree of Damocles, considered sacred by many indigenous peoples in Nepal, as his canvas. Photo by <PERSON>. Used with permission.\nTranslucent seeds of the tree of Damocles (Oroxylum indicum), meticulously glued together, form Nepali artist <PERSON>'s canvas. The round seeds, known for their medicinal values, are considered pure and sacred since they are enclosed in sword-shaped pods — far from the touch of bumblebees and other insects. In a nod to the seeds’ potential to grow into trees, <PERSON> tells the stories of discrimination and oppression meted out to indigenous Tamang people by the State — the Rana rulers in particular.\n“Called ko ko mhendo or heart flower in Tamang language, these seeds are ingrained in Tamang culture and rituals,” said <PERSON>, talking to Global Voices. “The Tamangs attach these seeds to invitations sent out on auspicious occasions. They have become symbols of Tamang identity.”\nThat’s why <PERSON> chose the sacred seeds to tell the stories, called Kaiten in the Tamang language. Kaiten is the Tamang oral story of origins of human life, culture and tradition, usually told by an elder storyteller, called <PERSON>. Like shamans using the seeds to heal sick people, <PERSON> uses them as a medium to heal wounds of the past, the wounds of torment and trauma.\nAlso read: Art series sheds light on the marginalization of indigenous Tharus in Nepal\nThe Tamang men were reduced to mere porters, palanquin carriers, hookah and umbrella bearers, and construction labour. The Tamang women, likewise, would work as nursemaids and wet nurses, while also singing, dancing and entertaining the rulers.\nPipa I, artwork by <PERSON>, shows the fate of Tamang people reduced to menial labourers. Photo by <PERSON>. Used with permission.\nThe Tamangs were barred from joining the British Army. The only rank for them in the Nepal Army was that of the pipa, the menial workers at the lowest rungs of the army.", "765" ], [ "They could never rise up the ranks. <PERSON> illustrates this through his artwork Pipa I, showing four men carrying doko, wicker baskets, on their backs.\nHis woodcut print on ko ko mhendo titled Gole Kaila features the protagonist <PERSON> aka <PERSON> who was martyred in 1950 in Biratnagar, a city in eastern Nepal. Though he died fighting against the <PERSON> regime to establish democracy, he was never accorded the status of a martyr.\n<PERSON>, woodcut on ko ko mhendo, portrays the protagonist <PERSON> who was never accorded the status of a martyr despite his sacrifice. Photo by <PERSON>. Used with permission.\nAnother medium <PERSON> chooses for his artworks is lokta, handmade Nepali paper, the same paper that his kinsmen produced from the bark of the Nepali paper plant and carried to palaces in the capital city Kathmandu as corvée (forced unpaid labour in lieu of taxes). The same paper carried orders and laws that would torment them further. But <PERSON> retells the story of his community’s anguish through the same paper. His artworks Kagaji Rakam, <PERSON> and <PERSON> show men in traditional attire but with their heads covered by, respectively, a bouquet of lokta flowers, a sheet of handmade paper and a bunch of mangoes.\nThe artworks Kagaji Rakam, <PERSON> and <PERSON> show how Tamangs were made to work as corvée labour. Photo by <PERSON>. Used with permission.\nExpanding on his work, <PERSON> said:\n“In order to pay taxes, Tamangs had to work for free for the State. The Tamangs from Bumtang of Nuwakot District had to collect lokta barks, process them into paper and carry those papers to the palace. Each household would need to produce 200 sheets of paper. Likewise, Tamangs had to work in fruit orchards and carry the fruit, especially mangoes to the palaces in Kathmandu. They had to leave Kathmandu the same day after dropping the fruit.”\nAlso read: ‘Opposite Dreams: The Politics of Local’: Art raises awareness around social issues in Nepal\n<PERSON> doesn’t stop here.", "765" ], [ "Ancient Pond Reconstruction in Kathmandu Stirs Preservation Protests · Global Voices\nRani Pokhari pond before the 2015 earthquake. Image by Flickr user <PERSON>. CC BY-NC 2.0\nPonds in the Kathmandu Valley and the southern plains of Nepal have always been an integral part of culture and tradition. While some ponds have been preserved well in the valley, others have been encroached upon by modern construction or have disappeared completely due to negligence by authorities.\nRani Pokhari, ‘the Queen’s Pond,’ with historic Balgopaleswor Temple in the center, has been drained off to allow for the temple's reconstruction. Authorities decided to renovate the pond as a whole after the temple was partially damaged by the disastrous earthquake of 2015.\nNow, activists and locals of Kathmandu Valley have come together to save this ancient pond in the heart of Kathmandu:\nकेही वर्षमा हामीले रानीपोखरीको यो हविगत बनायौं। एउटै स्थानबाट खिचेको दुई फोटो। #बाँदरको_हातमा_नरिवल। pic.twitter.com/9TLKxSDbMy\n— <PERSON> (@brazeshk) October 21, 2017\nIn few years’ time, we did this to <PERSON>. Two photos taken from the same point.\nThe beauty and historical significance of <PERSON>\n<PERSON>, a 17th-century heritage site, is believed to have been built by King <PERSON> in 1670 AD to console Queen <PERSON> who was saddened by the death of her youngest son.\nThe Balgopaleswor Temple in the center of the pond opens up to the public once a year when people with no siblings visit the temple during Bhai Tika, the ‘festival of brothers and sisters,’ on the final day of the Tihar festival, a five-day Hindu festival of lights.", "765" ], [ "The pond is also open to the public for the Hindu festival Chhath.\nView of <PERSON>, 1919 pic.twitter.com/TQKKSGvTaf\n— Nepal In Pix (@NepalInPix) December 7, 2017\npic.twitter.com/EGUWZ4NhA0\n— Old photos of Nepal (@oldphotosNepal) January 10, 2017\n<PERSON>. Old is Gold: Rani Pokhari before 1990's (Bikram Era) earthquake\nKnown for its beauty and historical significance, the pond is surrounded by Ghantaghar (the clock tower) and Trichandra College, Nepal’s first campus in the east, and Durbar High School, Nepal’s first high school in the west. On the southern bank lies a statue of King <PERSON> and his two sons riding an elephant. Temples dedicated to Hindu gods and goddesses stand at all four corners.\nControversial, messy reconstruction\nThe reconstruction of the pond has been a bone of contention between the government's Department of Archaeology, local people and the Kathmandu Metropolitan City (KMC) looking after the task. Construction work on the temple was halted when activists protested against the use of concrete materials by the contractor.\nThe row resurfaced after the contractor started building a concrete wall around the pond:\nThe KMC says it wants to “beautify and modernise” Rani Pokhari, complete with a son et lumière fountain, a park and coffee shop. This violates Nepal’s Ancient Monument Preservation Act which says historic sites over 100 years old have to be preserved in their original form.", "765" ] ]

[ 8065, 1414, 6394, 525, 5873, 7275, 8391, 7276, 4709, 10191, 216, 6009, 10908, 3212, 7610, 11038, 3899, 9262, 4574, 6778, 7474, 5443, 54, 3898, 9689, 3382, 43, 1950, 3965, 181, 10043, 1589, 11061, 6269, 6388, 9417, 1936, 5317, 7613, 3154, 8590, 9893, 5350, 4967, 3698, 1083, 4612, 9909, 9775, 3262, 781, 3981, 9312, 8154, 783, 11188, 6000, 883, 5427, 9405, 9796, 9156, 11375, 10683, 11216, 9781, 5936, 3337, 10989, 1355 ]

[ [ "Cheesecake\nIntroduction: Cheesecake\nI love cherries and I love cheesecake. I decided to bring both of them together and make my favorite dessert. This cheesecake is rich, and not so sweet. The fusion between the cheesecake and cherries is heavenly. Cheesecakes make every occasion special. It brings a smile to everyone's face. I am just happy knowing there is a slice of cheesecake on my plate.\nSupplies\nSupplies needed:\n9-inch springform pan\nMeasuring cup\nParchment Paper\nFoil\nBowl for mixing\nHandheld electric mixer\nA baking pan that would fit the springform pan\nStove-safe saucepan for making cherry sauce\nTeaspoon and tablespoon measuring spoons\nScissors\nSpatula\nCake Stand\nIngredients for cherry sauce:\n1/2 cup fresh cherries, seeds removed\n1 tablespoon sugar\n1 teaspoon vanilla extract\n½ cup water\nIngredients for the crust:\nCooking spray\n2 cups crushed <PERSON> crackers\n1/4 cup brown sugar\n3 tablespoons unsalted melted butter\nParchment paper\nFoil\nIngredients For the filling:\n20 oz cream cheese\n3/4 cup sour cream\n¾ cup granulated sugar\n2 teaspoon pure vanilla extract\n4 large eggs\nStep 1: Preheat the Oven\nPreheat the oven to 325 degrees.\nStep 2: Get Springform Pan Ready\nCut parchment paper in a round shape to line the bottom of the pan. Line the sides of the pan with a piece of foil. Then spray the springform pan.\nStep 3: Make the Cherry Sauce\nAdd cherries, sugar, vanilla extract to the saucepan. Add half a cup of water and simmer the fruit till it becomes a thick sauce. Use medium heat and stir some to avoid sticking to the pan.\nStep 4: Prepare the Crust\nGrind the graham crackers in a food processor.", "456" ], [ "Add brown sugar and melted butter and combine with the ground graham crackers. Mix well. These ingredients are for the crust. Add them to the springform pan and press to make an even crust.\nStep 5: Prepare the Filling\nAdd cream cheese, vanilla extract, sour cream, sugar and mix with the hand mixer. Add eggs one at a time and keep mixing till the filling has no lumps and appears creamy.\nStep 6: Fill the Pan With Filling\nPour the filling on top of the crust in the springform pan.\nStep 7: Prepare the Water Bath\nFill the baking pan with around 1 inch of water. Put the springform pan in the baking pan.\nStep 8: Top the Cheesecake With Cherry Sauce\nTop the cheesecake with cherry sauce. You can take a toothpick and create swirly patterns with the sauce.\nStep 9: Bake the Cheesecake\nBake the cake at 325 degrees for around 45 minutes. Overbaking the cake creates cracks.\nStep 10: Cool the Cheesecake\nCool the cheesecake at room temperature and put it in the refrigerator. The next day you can remove the cheesecake from the refrigerator and gently remove the sides of the springform pan and the foil. Place the cake on the cake stand. Leave the parchment paper base on\nStep 11: Enjoy!\nA slice of cheesecake makes everything all right! Partner cherry and cheesecake, and you will have a taste explosion. All you need is love and a slice of this cheesecake.", "891" ], [ "Pumpkin Cinnamon Pull-Apart Bread Recipe\nIntroduction: Pumpkin Cinnamon Pull-Apart Bread Recipe\nFor the first time, I am doing virtual learning!\nOne of the first projects my teacher gave us was to make something pumpkin related. Since I love baking, I decided to bake something out of pumpkin. After looking at many recipes, I narrowed it down to Pumpkin Smores, Pumpkin Muffins, and Pumpkin Cinnamon pull-apart bread. I chose Pumpkin Cinnamon pull-apart bread as it is not to hard to make, and it tastes incredible! This will be my first time making it.\nStep 1: Ingredients\nFor The Bread:\n2 tbsp. butter, melted\n1/2 cup pumpkin purée\n1/4 cup brown sugar\n1 tsp. pumpkin pie spice\n1/2 tsp. kosher salt (I used regular salt)\n1 large egg, beaten\n3 1/4 cup all-purpose flour, plus more as needed\n1 (1 1/4-oz.) packet Fleischmann's RapidRise Yeast\n1/2 cup milk, very warm ( microwave for about 20-30 seconds)\nCooking spray\nFor The Filling:\n4 tbsp. butter\n4 tsp. pumpkin pie spice\n1 1/2 cups brown sugar\nFor The Glaze:\n1 1/2 cups powdered sugar\n3 tbsp. milk\nStep 2: Making the Dough\nIn a large bowl, whisk together melted butter, brown sugar, pumpkin puree, pumpkin pie spice, and salt until smooth. In the same bowl add flour, beaten egg, and Fleischmann’s RapidRise yeast.", "851" ], [ "Stir using a wooden spoon, add warm milk, and keep stirring till doughy.\nStep 3: Knead the Dough\nTransfer the dough to a floured surface and knead, add a little more flour if the dough feels sticky. Keep kneading for about 5 minutes till the dough is smooth and elastic. Cover dough with clean dish cloth and let it sit for 10 minutes.\nStep 4: Filling\nAs we wait for the dough to sit, lets make the filling! In a small bowl, mix together 4 tablespoons of butter, pumpkin pie spice, and brown sugar until paste forms. Line two 9” x 5” loaf pans with parchment paper and grease with cooking spray.\nStep 5: Put the Filling on the Dough\nRoll the dough out into a large rectangle, about 18 inches by 12 inches. Spread the filling all over the dough in an even layer. Cut dough lengthwise into 8 even strips, then stack the strips on top of each other in two stacks of 4 strips. Cut stacked strips into 6 rectangles each and place the cut side up into the prepared pans.\nStep 6: Baking\nPreheat the oven to 350°F. Bake for 30 minutes until puffy and golden. Let cool at least 15 minutes on a wire rack, then remove from pans and transfer to a serving plate.\nStep 7: Making the Glaze\nIn a small bowl, whisk together powdered sugar and milk until smooth. Drizzle glaze over loaf and serve warm.\nStep 8: Then Your Done!\nThe recipe turned out very well! It reminded me of cinnamon rolls.\n*Tips and tricks*\n* Instead of using a spoon to mix the dough I used my hands which made it easier to knead the dough.\n* It's recommended to use the two bread loaf pans as mentioned in the recipe. Since I did not have the two 9\" x 5\" loaf pans, I ended up using 1 loaf pan and 1 cake pan.", "891" ], [ "Festive Cake Pops\nIntroduction: Festive Cake Pops\nAs Christmas time is coming around I thought I should make a fun treat with festive colors. I love the Starbucks cake pops but it is so much more expensive to buy there than to make at home. These cake pops are simple, delicious, and fully customizable whether you use a store bought cake and icing or make it homemade.\nSupplies\nIngredients -\n-1 2/3 cups all purpose flour\n-1/4 teaspoon baking soda\n-1/2 teaspoon baking powder\n-1/2 teaspoon salt\n-1 cup whole milk whole milk\n-7 tablespoons unsalted butter\n-1 cup granulated sugar\n-3 teaspoons vanilla\n-1 egg\n-1 3/4 cups powder sugar\n-White chocolate candy melts\n-sprinkles\n-cake pop sticks\nTools -\n-oven (to bake the cake)\n-fridge/freezer (to chill the cake pops)\n-Microwave safe bowl (to melt the chocolate)\n-11x7 cake pan (to bake the cake in)\n-whisk (to mix the ingredients)\n-stand mixer (to mix the ingredients)\n-toothpick (to check the cake)\n-parchment paper (to let cake pops rest)\nStep 1: Make the Cake (skip If Using a Box Cake)\n1. Preheat oven to 350 degrees Fahrenheit and grease an 11x7 cake pan.\n2. Whisk flour, baking powder, baking soda, and salt in a medium bowl and set aside.\n3. In a stand mixer with a paddle or whisk attachment, beat butter and sugar together until creamed - about 2 minutes.\n4. Add egg and vanilla extract and beat on high speed until combined. Scrape down the bottom and sides of the bowl if needed.\n5. With mixer on low speed, add dry ingredients and milk to wet ingredients.\n6. Pour batter into a greased pan and bake for 30-36 minutes and until a toothpick comes out clean.\n7. Let the cake cool completely in the pan set on a wire rack.\nStep 2: Make the Frosting (skip If Using Store Bought)\n1. With a stand mixer and paddle attachment, beat butter on medium speed until creamy - about two minutes.\n2.", "305" ], [ "Add powdered sugar, milk, and vanilla extract with the mixer running on low.\n3. Increase to a high speed and beat for 3 minutes.\nStep 3: Crumble and Form the Cake Balls\n1. Crumble cooled cake into a bowl on top of the frosting and make sure there are no large lumps.\n2. Turn the mixture on low and beat frosting and cake crumbs together.\n3. Measure 1 tablespoon of cake mixture and roll into a ball.\n4. Place balls on a lined baking sheet and either refrigerate for at least 2 hours or freeze for at least 1 hour.\n5. Re-roll the chilled balls to smooth out.\nStep 4: Melt Chocolate and Coat the Cake Pops\n1. Melt chocolate in a two cup liquid measuring cup in the microwave.\n2. Take 2-3 cake balls from the fridge at a time.\n3. Dip a stick about 1/2 inch into the coating and insert into the center of the cake ball, only pushing halfway through.\n4. Dip cake pop into coating making sure it covers the base where the stick is.\nStep 5: Decorate the Cake Pops\nYou can decorate these cake pops with whatever you want. Some things you can use are sprinkles, chocolate chips, m&ms, etc. The coating hardens fast so make sure you do everything quickly.", "195" ], [ "Fruit & Cheesecake Spread Sandwich\nIntroduction: Fruit & Cheesecake Spread Sandwich\nThis sweet and refreshing sandwich will satisfy your sweet tooth without leaving you feeling like you ate a dense dessert. I love desserts and figured if there are dessert pizzas, there should be a dessert sandwich. I was inspired by Japanese desserts because they're sugary but light, so I went to the Japanese Market to get some Japanese bread. It's sweet and fluffier than typical bread which was perfect for this sandwich. The delicious cheesecake spread complements the fruit and only requires 4 ingredients. For this recipe, I put strawberries and raspberries on my sandwich, but you can use any of your favorite fruits.\nSupplies\nTo make this sandwich, you will need:\n2 slices of bread (I used Japanese bread)\nFruit(s) of choice\n1/4 cup butter, softened\n4oz.", "763" ], [ "cream cheese, softened\n1/2 cup powdered sugar\n1tsp. vanilla extract\nYou will also need:\n1 medium sized bowl\nHand mixer or spatula\nMeasuring spoon\nMeasuring cup\nKnife to cut fruit and spread cream cheese mixture\nStep 1: Beat Cream Cheese & Butter\nBegin by combining the cream cheese and butter with a hand mixer or spatula on low speed. Make sure cream cheese and butter are softened so the mixture is smooth.\nStep 2: Add in Powdered Sugar & Vanilla\nAdd the powdered sugar and vanilla extract to the cream cheese mixture and mix until fully combined. If there is extra cheesecake spread, you can use it as a yummy dip for fruit or crackers.\nStep 3: Preparing Fruit\nWash and cut your fruit so it is ready to go onto the bread. I used strawberries and raspberries, but any fruits would work. Make sure that when slicing your fruit it is able to lay flat on the bread.\nStep 4: Making the Sandwich\nArrange your sliced fruit onto one piece of bread and put the cheesecake spread on the other. Place this piece of bread onto the fruit.\nStep 5: Finishing the Sandwich\nFinally, you can cut your sandwich in half and enjoy your dessert sandwich! This simple treat is easy to make but tastes delicious.", "851" ], [ "Triple Chocolate Custard\nIntroduction: Triple Chocolate Custard\nThis triple chocolate custard is a delicious and comforting dessert that is so easy to make and tastes incredible!!! why have one type of chocolate custard when you can have all three?? This is a staple in my house and I hope that you try it too.\nSupplies\nIngredients\n* 600ml Full cream milk\n* 6 Egg yolks\n* 100g Caster sugar\n* 50g Cornflour\n* 50g cold unsalted butter (keep it in the fridge until use)\n* 1 Vanilla bean pod (or 1 tsp vanilla bean paste)\n* pinch of salt\n* 70g white chocolate\n* 70g milk chocolate\n* 70g dark chocolate\n* Decorations (strawberries, whipping cream, extra chocolate)\nEquipment\n* Whisk\n* Medium Saucepan\n* Knife\n* Small whisk\n* Microwave\n* Mixing bowls and spoons\n* Serving glasses or bowls\n* Piping bag\nStep 1: Heat Milk\nIn a medium saucepan heat the milk and vanilla bean on medium heat until it lightly simmers. Allow it to cook for a few minutes if there are lumps from the bean sieve them out.\nStep 2: Prepare the Egg Mixture\nIn a mixing bowl whisk together the egg yolks, sugar and cornflour for a few minutes until it becomes light and fluffy.\nStep 3: Mix Together\nOnce both mixtures are ready pour a few tablespoons of warm milk into the egg mixture and whisk together. Ensure you add small amounts of milk so you don't cook the eggs with too much hot liquid. once it is all added place the custard back onto the heat and then continue to whisk for a few minutes until it thickens. this may take about 3-5 minutes.", "604" ], [ "Then take the custard off the heat, allow it to cool for 5 minutes and whisk in the cold butter.\nStep 4: Melt and Add the Chocolate\nMelt each of the white, milk and dark chocolates in the microwave at 30-second intervals, stirring in between. Then divide the custard into 3 separate mixing bowls. Then add one chocolate type to each bowl of custard and mix to combine.\nStep 5: Pipe Into Serving Bowls\nPlace each chocolate custard into a piping bag or ziplock plastic bag. Cut the tips off the bag and then pipe the different custards into the serving bowls. I like the gradient of dark chocolate on the bottom, milk chocolate in the middle and white chocolate on top.\nTo decorate place some whipping cream, a serrated strawberry or grated chocolate, whatever you may want!\nStep 6: Serve!\nServe it straight away as a warm custard or chill in the fridge for a few hours to serve cold.\nI hope that you enjoy these beautiful desserts!!", "136" ], [ "Chocolate Cookies With Maraschino Cherries\nIntroduction: Chocolate Cookies With Maraschino Cherries\nEasy and sweet cookies that are perfect for sharing with your family and friends! Cherry and chocolate combination will make anyone crave more. This is especially good for upcoming holidays like Christmas.\nThey are made for chocolate lovers, who don't have time to make a chocolate cake. Cookies are easy to make and they bake only 10 minutes.\nThese cookies will make you life sweeter and any day brighter.\nHighly recommend them to store in the fridge and have one on a bad day! Well, they make a good day even better!\nCrispy outside and chewy inside. Perfect treat to have with tea, coffee or milk!\nTempting Chocolate Cherry Cookies were first published on our blog.\nSupplies\n1,5 cup flour\n1/4 cup white sugar + 1/4 cup brown sugar\n2/3 cup unsweetened cocoa powder\n1/4 tsp salt\n1/4 tsp baking powder\n1/4 tsp baking soda\n1/4 tsp vanilla powder or extract\n1/2 cup butter\n2 medium eggs\n1 tbsp maraschino cherry liquid, mixed with powdered sugar to syrupy consistency\n1/4 cup melted chocolate\n1/2 cup milk\n1 cup maraschino cherries\nextra crushed almonds for serving\nYou will need hand mixer, scoop, spatula and baking tray with parchment paper\nStep 1: Prepare Dry Ingredient\nIn one bowl mix all dry ingredients with a spoon: flour, cocoa, all sugar, baking soda, baking powder, vanilla powder and salt.\nNo need to sieve them, just combine well.\nStep 2: Mix Butter and Eggs\nIn another bowl, beat butter with a hand mixer, scraping the sides until pale.\nAdd eggs and mix until combined.\nGradually add few tablespoons of dry ingredients. Mix until just combined.\nStep 3: Prepare the Cookie Dough\nSwitch to the spatula.\nAdd half of dry ingredients and mix with a spatula.", "851" ], [ "Add milk, so it will be easier to mix together.\nAdd remaining dry ingredients and mix until combined.\nAdd maraschino syrup and melted chocolate. Combine until smooth.\nStep 4: Chill in the Fridge\nCover the bowl with plastic wrap and leave in the fridge for at least 30 minutes or 1 hour.\nThis part is essential, so don't skip it! Chilling the cookies will make them more flavorful and they will spread less, while baking.\nStep 5: Make the Chocolate Cookies\nScoop the balls to the baking tray, layered with parchment paper.\nYou can roll the balls in your palms. Dust the hands with extra cocoa powder, so it will be less messy!\nPress the centre of each cookie with your thumb.\nPut cherry on top of each chocolate cookie.\nStep 6: Bake and Decorate\nBake 10-15 minutes in the oven, preheated to 356 F / 180 C.\nThe more you bake, the crispier cookies will be. But the cherries will become more dry, too.\nLet them cool on the wire rack. Sprinkle with crushed almonds.\nEnjoy!\nThey will keep in the fridge up to 6 days or 1 day at room temperature.", "195" ], [ "Chocolate Chip Cream Cheese Bars\nIntroduction: Chocolate Chip Cream Cheese Bars\nChocolate Chip Cream Cheese Bars are great for parties, get togethers or just for family. It easy and fun to make for all ages, it just requires three ingredients.\nSupplies\n* Two 16.5 oz rolls of raw Pillsbury chocolate chip cookie dough\n* Two (8 oz) packages of Philadelphia cream cheese, softened\n* 1 cup of sugar\n* A 13 x 9 pan with a lid\n* Non-stick spray\n* 1 cup measuring cup\n* Oven\n* Oven mitts\n* Electric mixer\n* Timer\n* Plastic Spatula scraper\n* Tooth picks\nStep 1: Mixing the Cream and Preparing the Oven\nPlace the two 8 oz packages of soft Philadelphia cream cheese and 1 cup of sugar into the mixing bowl.\nPut the pretzel mixer onto the rotator.\nLower the top before locking it into place.\nTurn the mixer on at the 4th speed.\nWhile the cream and sugar are mixing, preheat the oven to 350 degrees.\nStep 2: Preparing the Pan and Laying the Bottom\nTake the 13 x 9 pan and spray the bottom and sides with non-stick cooking spray.\nTake 1 and a half tubes of Pillsbury chocolate chip raw cookie dough and press it down until there is 1 1/4 inches on the bottom.\nStep 3: Put the Bars Together\nOnce the cream and sugar has become creamy, stop the mixer and lift the top up.\nRemove the mixer bowl from the mixer and grab the plastic spatula scraper.\nPut all of the cream cheese and sugar mixture into the pan on top of the cookie dough.\nSpread the mixture evenly over the top.\nTake the remaining cookie dough and put small chunks over the top of the cream cheese.\nStep 4: Cooking the Bars and Checking\nOnce the oven has preheated, place the pan into the oven and start the timer for 35 minutes.\nAfter the timer goes off, put the oven mitts on and take the pan out of the oven.\nTake a toothpick and stick it in the middle of one of the chunks.\nIf the toothpick comes out clean then turn off the oven and let the pan cool.\nIf unsure, stick the pan back into the oven for another 2 minutes.\nRefrigerate the pan with a lid if the entire pan is not eaten within the first day.\nStep 5: Video Process", "136" ], [ "Sweet Potato Casserole in a Pumpkin Bowl\nIntroduction: Sweet Potato Casserole in a Pumpkin Bowl\nI will be making a delicious sweet potato casserole in a pumpkin bowl. This is a perfect treat to make for the holidays and fall time! On top of that, it looks really pretty as well. This is one of my favorite things to eat with a cute touch.\nStep 1: Ingredients\nThis can serve for 4!\n* 4 bowl sized pie pumpkins\n* 4 cups of peeled and cubed sweet potato\n* 1/4 cup white sugar\n* 1 egg (beaten)\n* 1/4 teaspoon salt\n* 2 tablespoons butter, softened\n* 1/4 cup milk\n* 1/4 teaspoon vanilla extract\n* 1/4 cup packed brown sugar\n* 1/4 cup all-purpose flour\n* 2 tablespoons butter softened\n* 1/4 cup chopped pecans\n* (optional) marshmallows\n* (optional) 1/8 teaspoon cinnamon + all spice\nStep 2: Preparing the Pumpkins\nWash pumpkins.\nHeat pumpkins in the microwave for about 7-8 minutes and periodically check the pumpkins as microwave temperatures can vary. This is so that the pumpkins are easier to cut! Using a very sharp knife, carefully cut around 1/2 to 1/3 of the top off and scoop out the insides to create bowls.\nPlace pumpkins in a 9 x 13 inch baking dish with about 1/2 inch of water. Place in the oven and bake for 40 minutes at 350 degrees Fahrenheit or until the pumpkins are tender. While the pumpkins are baking, start making the casserole!\nStep 3: Making the Casserole\nPut the cubed sweet potatoes in a medium saucepan with water to cover. Boil at medium high heat for about 15 minutes or until tender. Once cooked, drain the water and mash in a separate large bowl.", "2" ], [ "After the potatoes have been mashed, add the white sugar, egg, salt, butter (2 tablespoons), milk, and vanilla extract. Mix with a beater until smooth. Add the cinnamon and all spice in now if you choose to include it!\nStep 4: Make Casserole Toppings\nIn a medium bowl, mix your brown sugar and flour. Add in the butter and then the chopped pecans. Mix until coarse.\nStep 5: Fill Pumpkins and Bake\nTake the baked pumpkins out of the oven and add the sweet potato mixture first. Leave room for the topping! Add the brown sugar, flour, butter, and pecan mixture on top of the sweet potato mix. Add marshmallows if you would like!\nPreheat oven again to 350 degrees Fahrenheit. Fill the 9 x 13 baking dish with a little bit of water. Place in oven and bake for 30 minutes.\nStep 6: Eat and Enjoy!\nAfter they have been baked, let cool and enjoy! The good news is is that the pumpkin is edible as well ;)", "195" ] ]

[ 1197, 6042, 7697, 6862, 8967, 7767, 11287, 10289, 2751, 2964, 6985, 521, 8195, 8165, 5824, 925, 7518, 4947, 8410, 8014, 11201, 9077, 5762, 5129, 3707, 1989, 1439, 4810, 7812, 11239, 6011, 4436, 3845, 3772, 5823, 1428, 1354, 3657, 8666, 8799, 330, 10840, 10372, 11418, 488, 1516, 520, 6077, 9914, 2077, 10619, 11108, 7888, 11218, 10428, 1123, 2282, 10956, 3276, 7060, 7953, 1695, 5996, 4663, 10512, 10806, 10967, 2409, 8357, 9770 ]

[ [ "They have been shown to upgrade repeatedly. The original Daleks, shown in Genesis of the Daleks, had a Mark III Travel Unit, with no significant difference between Daleks. Later (from the <PERSON>'s perspective, earlier from the Doctor's perspective) Dalek units differentiate into specialized units for research, strategy, navigation, and leadership. An excellent example of this is the Emperor <PERSON> in the Second Doctor episode Evil of the Daleks. By the Time War, they have developed improved materials, weaponry, and design - the \"brass\" or \"gold\" Daleks we see most often in the new series. We also see in Day of the Doctor and Time of the Doctor that they used additional weapons platforms and modified Dalek forms for their assault.\nEarly on, the power supply was shown to improve as well. Starting with static electricity provided through the floors, then a radar-dish like receiver, then solar panels, then mention of internal energy sources that have moved into the realm of throwaway technobabble lines.", "837" ], [ "It is difficult to follow the progression from their creation to their early appearances, because the first several cases progressed from The Daleks in 1963 where the Daleks did not believe in life from beyond Skaro, then Genesis of the Daleks changed history so that the Daleks had always known of the Doctor.\nThrough the series, there have been many non-visual upgrades. Weapons and shield improvements that are mentioned or demonstrated, but not obvious, greater mastery of time travel, greater mastery of biological weapons and strategy improvements. What once took a Special Weapons Dalek is now beneath the level of \"maximum extermination\" that drones are capable of.\nMost importantly, they are able to combat <PERSON> technology. Where early on, the Doctor merely had to get to his TARDIS to escape, the Daleks later could divert its course, and more recently utilized a chronon loop to stop it entirely. Where it was once invulnerable (except to overgrown snails), the Daleks were able to easily disable it and all indications were that the method they were using to destroy it would have been successful if not for the metacrisis Doctor and the Doctor-Donna. Where they were once helplessly scooped up by ancient <PERSON> devices, the Cult of Skaro could temporally shift without external devices.\nThe Dalek ability to adapt quickly and either develop their own or reverse engineer technology to become an even worse threat has been a major theme. This began with The Chase, when they reverse engineered time travel and dimensional transcendence technology from observing the Time Lords. In the new series, they outmatch the Time Lords who were once the greatest power in all of time and space.", "837" ], [ "As you alluded to, the original run of Doctor Who had the Daleks \"wiped out\" repeatedly as well. Since you only list the 2005 and onward, though, I will stick to that. I'll first clarify your points:\n* The Parting of the Ways, <PERSON> destroyed all the offending Daleks in the fleet created from the DNA of <PERSON>, along with the Emperor himself. At that juncture, no one involved in that story knew other Daleks survived. Even assuming <PERSON> had knowledge of the entire universe (which, there is nothing to indicate she did), they were outside the universe in the Void at this time.\n* Doomsday involved Daleks who had hid out in the Void at the end of the Time War, avoiding demise in all previous episodes. There were two groups - those from the <PERSON> prison, and the Cult of Skaro. The Cult of Skaro used an emergency temporal shift, and the rest were sucked into the Void. In The Next Doctor, it is revealed that these Daleks in the Void were working on a way out, which the Cybermen stole. These Daleks may yet return.\n* Daleks in Manhattan/Evolution of the Daleks - <PERSON> survived, as you point out.\n* Journey's End - These Daleks are not the original Daleks, they are new creations from <PERSON>' own cells, but like the previous Daleks, they go against him. The Metacrisis Doctor is the one who does the destroying, not <PERSON>, by sending what amounted to a self-destruct signal.", "837" ], [ "There are many excuses possible, but none specified as to why a few Daleks did not self destruct.\n* Victory of the Daleks - It's World War II. <PERSON> makes reference to World War I, but it is shown in the episode that he isn't really that old.\nTo your first question, \"aren't the Daleks cheating against the Doctor?\" - All is fair in love and war. This is at least war, but Asylum of the Daleks implied the other might apply too. The one item you reference that is \"cheating\" is <PERSON> breaking through the Time Lock - and it is stated in the episode what happens here. <PERSON> lost his mind in the process, being exposed to the vast temporal energies of the paradox his involvement was creating. This insanity is precisely why the Doctor doesn't break the Time Lock - that, and it's explicitly stated in The End of Time that the Doctor was intentionally responsible for <PERSON> being caught in the Time Lock due to the horrific plan <PERSON> had to win the war. In short, the Doctor felt that the Time Lords were a greater threat to the universe than the Daleks.\nTo your second question, \"Why doesn't the Doctor go back to a time before the Time War (which is not time locked) and \"breed\", just like the Daleks?\" - He wouldn't need to time travel to produce more of his kind, if that were his goal - the children could just travel after they are old enough. I think you are actually asking why he doesn't go back to Gallifrey and do something about his people. The reason for this is that the Time Lock encompasses the Time War. They have shown in The Invasion of Time in 1978 that if you are in a war as a time-active people, the first thing you try is to time-loop the enemy's entire history, which means all of Gallifrey's relevant history is locked. He could potentially have children, and inadvertently did with <PERSON> (who was shown to still be alive) in The Doctor's Daughter, but given that he intentionally destroyed the Time Lords, he wouldn't be recreating them unless there was a new plot-driven motive.", "837" ], [ "Technically not always, in \"An Unearthly Child\" we are introduced to the TARDIS and it appears it is the first time the chameleon circuit has failed. The Doctor says:\nIt's still a police box. Why hasn't it changed? Dear, dear, how very disturbing.\nThis establishes that the TARDIS is now stuck as a police box, but <PERSON> reveals that it wasn't always a police box:\n<PERSON>: It should have changed. Wonder why it hasn't happened this time.\n<PERSON>: The ship, you mean?\n<PERSON>: Yes, it's been an Ionic column and a sedan chair.\n<PERSON>: Disguising itself wherever it goes.\n<PERSON>: Yes, that's right. But it hasn't happened this time. I wonder why not.\nIn the \"Attack of the Cybermen\" serial, the TARDIS changes several times after the Doctor attempts to fix the chameleon circuit.", "837" ], [ "First into an ornamental dresser, as outlined in the script below:\nDOCTOR: This looks familiar.\n<PERSON>: Where are we?\nDOCTOR: Scrap yard.\n<PERSON>: I didn't mean that. I meant, whereabouts on Earth are we?\nDOCTOR: London.\nPERI: It didn't change.\nDOCTOR: Hmm?\nPERI: I thought you said it was going to blend into its surroundings.\nDOCTOR: Oh, she's probably thinking about it. Come on, let's find out where those signals are coming from.\n(The Tardis changes into a highly ornamented dresser.)\nPERI: Oh, neat, Doctor.\nDOCTOR: Neat?\nPERI: Very neat. I mean, there's nothing at all incongruous about that.\nDOCTOR: Well, she hasn't done it for a long time. She's out of practice.\nPERI: Of course, Doctor.\nHere is the TARDIS shown in mid-transformation and as the final dresser.\nLater it transforms into a pipe organ (as pictured) and the Doctor plays it briefly.\n(The Tardis materialises in <PERSON>'s junk yard as a small pedal pipe organ.)\nDOCTOR: This is getting ridiculous.\nPERI: I'm not saying a word.\nDOCTOR: I was certain I'd fixed it.\n(He pulls out a stop and plays the opening line from <PERSON> Toccata and Fugue in B Minor.)\nAnd lastly it turns into a gate.\n(A pair of large wrought iron gates, the sort you'd find at the entrance to the driveway of a very large house, materialise in a corridor. The Cybermen lead their captives out.)\n<PERSON>: What happened to the organ?\n<PERSON>: Do you really want to know? Oh, this place is so cold!\nThe TARDIS is also shown undisguised in \"The Name of the Doctor\" silver-grey cylinder.\nThis varies slightly from the undisguised TARDISes shown in \"The War Games\" serial.", "837" ], [ "While it can be difficult to come up with an in-universe explanation for something that has an out-of-universe explanation of different effects techniques, and possibly a much better budget, let's try.\nTL;DR - We can theorize that the more regenerations a Time Lord has gone through, the more difficulty they have during/immediately after a regeneration.\nLooking back to the regenerations from the original series, we see no significant mental trauma or confusion involved in the earliest regenerations. While the 2nd Doctor was different from the first, most of the confusion in his regeneration came from his companions, who simply weren't entirely sure this was the same person. That element didn't really come up again, from what I've seen (he had active companions during the regenerations from 3->4, 4->5, 5->6, 6->7, 9->10, and 11->12, at least).\nStarting with the 4th regeneration, into the 5th Doctor, we started to see significant mental issues - calling people by the names of old companions, and the like. While the regeneration into the 5th Doctor seemed the worst (and the Master may have had something to do with that), the 6th and 7th Doctors both showed some confusion and distress at first (haven't watched the 8th Doctor movie recently enough to recall - but he did say he was part human then, which has basically been disavowed by now, I believe).\nSomething unique to the 4->5 regeneration was the Watcher - who was, apparently, the Doctor in a state in between his 4th and 5th forms, bouncing back in time to \"watch\" the 4th's last adventure.", "837" ], [ "This can be handwaved away for any of a number of reasons - his visit to Logopolis and its unique nature, and the possibility of the Master's involvement in order to manipulate him into going to Castrovalva being the two that leap to mind.\nStarting with <PERSON>, we've seen a certain amount of physical trauma as well, in the form of the regeneration fire apparently causing the physical change. I haven't seen the regeneration into the 12th Doctor yet, but the explanation that the majority of the change was accomplished earlier, and the \"sneeze\" just adjusted the cosmetics, seems roughly credible to me. (I think we were also told that the Doctor had been putting the full regeneration off for some time, leaving his 11th form to limp along after it should have been replaced, which could account for some special oddities here.)\n(That said, the idea that the regeneration from 9 to 10 wasn't using the fire as a standard regeneration technique, but as something caused by the Vortex energy, also seems entirely credible out-of-universe. And, so does the idea that, whether due to the team involved forgetting that fact, or simply due to the \"coolness\" factor, this became a part of the standard regeneration).\nThis leads to a logical (though not explicitly stated in canon) theory that the older a Time Lord is (or the more regenerations they've gone through), the harder a regeneration is on them.\nI should note that I believe there are two regenerations that happened off-screen: the regeneration from the 2nd Doctor to the 3rd, and the War Doctor to the 9th.", "837" ], [ "Well there are many powerful objects in the Whoniverse;\nMany are Gallifreyan artefacts that carry the name of <PERSON>. These included the Sash of Rassilon, the Rod of Rassilon (TV: The Deadly Assassin), the Coronet of Rassilon (TV: The Five Doctors), the Harp of Rassilon (TV: The Five Doctors), the Crown of Rassilon (TV: The Invasion of Time) and the Seal of Rassilon, a symbol used as a mark of Time Lord authority which appeared as a motif in many Time Lord designs (first seen in TV: The Deadly Assassin, named in TV: The Five Doctors) (The Crown)\nThese were stored in the Capitol and, except for the supremely powerful Great Key,were made available to the Lord President of the Time Lords. (TV: The Invasion of Time). The Black Scrolls of Rassilon, contained forbidden, arcane secrets (TV: The Five Doctors).\nThe Ring of Rassilon capable of conferring immortality upon the wearer, resided in the Tomb of Rassilon in the Dark Tower located in the Death Zone. (TV: The Five Doctors)\nBUT what is said to be the most powerful object in the Whoninverse is the Moment.\nThe most powerful and most dangerous weapon in all of creation (not the T.A.R.D.I.S.), described as the Galaxy Eater it is capable of whole galaxies within in a single moment, hence its given name.Able to create tears in the fabric of creation called time fissures that would allow people and objects to pass from one time period to another, possessing a trans-dimensional awareness of the past and future. It also had a sentient interface with telepathic abilities, enabling it to read the thoughts and memories of those who intended to use it.\nThe interface also had the capacity to take the forms of others as a holographic projection.", "837" ], [ "As it was a Time Lord construct, it was not limited to a linear grasp of time and space- it could select the forms of people from an individual's future they had yet to meet.It can also change appearance from a box full of gears, to a box looking station with a big blood red ruby button on a stalk, with a base similar to the shape of a rose petal.\nThe Moment was the final creation of the Ancients of Gallifrey. It had an operating system so sophisticated and advanced it had become sentient and developed a conscience. This is why it was never used, as the Time Lords feared its moral judgement). When attempting to initialise it, the War Doctor expressed unfamiliarity with the Moment's controls and operating system. (TV: The Day of the Doctor) According to another account, however, the Eighth Doctor created the Moment from a modified Key of Rassilon and De-mat Gun during the Time War. (COMIC: The Forgotten, Don't Step on the Grass)\nUntil the Doctor stole it, the Moment had been locked away along with other forbidden weapons,collectively known as the Omega Arsenal, in the Time Vaults. While all the other weapons were used against the Daleks during the course of the Time War, the Time Lords refused to use the Moment for fear that it would punish anyone who did so.\n(RE:multiple TDC/OTHER entries)", "837" ], [ "How can <PERSON> pilot a TARDIS? [Spoilers]\n<PERSON> pilot a TARDIS\n! with <PERSON>, in the end of Hell Bent.\nBut, except for short or emergency flights, normally with the presence of the Doctor alongside, no human (River Song isn't pure human) would have been able to pilot the Doctor's TARDIS by themselves. There are many difficulties with the way it's portrayed:\n1. <PERSON> is shown reading the manual, which is written in Gallifreyan, arguably one of the most complex and difficult languages to learn and understand in the universe. I'd imagine a cross of Chinese with Category Theory (in math) might be similar to nursery level in Gallifreyan. Not only the language is difficult, many of the concepts probably don't even exist in human language.\n2. Piloting the TARDIS (safely, at least) should depend on an extensive knowledge of temporal mechanics which would have been beyond the capabilities of a human brain, no matter how long they'd have to study it. The Doctor was seen trying to teach <PERSON> how to pilot the TARDIS, yes, but the \"safely\" is still open for discussion. The TARDIS can destroy the Universe in case something wrong happens (see Big Bang).\n3.", "837" ], [ "Being human, both lack the Time Lord temporal senses, which may have something to do with piloting the TARDIS as well. Like having eyes to be able to fly a plane.\n4. Most crucially, I think, as <PERSON> they'd lack the symbiotic nuclei, which AFAIK are necessary to establish the symbiotic bond between the TARDIS and its pilot (I believe it's said in PROSE: Interference - Book One).\nThe TARDIS will die if its pilot dies, so it's not like someone can simply take over a TARDIS. They need their pilot. River Song has been modified by the Silence with many Time Lord characteristics, including the symbiotic nuclei which are also necessary for the regeneration, besides having a connection to the Vortex from the moment of her conception. Even so, she needed the Doctor's TARDIS teaching her. How did <PERSON> and <PERSON> manage it, with a bog-standard TARDIS which wouldn't be accostumed with non-Time Lord passengers, let alone a non-Time Lord pilot?\nAnother point is that with all the trouble the Doctor finds traveling in the TARDIS, having a pair of humans flying around with a TARDIS of their own is a serious risk of universe-destroying paradox. For example if <PERSON> manages to get \"killed\" along the way, with no Doctor to save them. Remember the Doctor deactivated <PERSON>'s Vortex manipulator for this reason, and <PERSON> was a trained, and experienced, Time Agent.", "837" ], [ "The clothes reflect how the Doctor is changing throughout his run. For example, after the Christmas episode of season 8 this article states that the Doctor is lightening up a bit:\n<PERSON> has revealed that the <PERSON> Doctor will return to season nine much different than he was in season eight. “We’re not bringing him back exactly the same as we left him, at all. I think that was already evident at Christmas,” he explained. “He’s left some of the burden of being the superhero of the universe behind.”\nSo considering he's not going to be showing off himself as a hero he may have felt that he didn't have to bother too much about whether or not he looked good.\n**\n<PERSON> outfit did change.\nWikipedia says:\nThe Doctor's initial outfit, chosen within the narrative of \"The Eleventh Hour\" from an array of clothes found in a hospital, is a brown tweed jacket with elbow patches, bow tie, suspenders, black trousers and black, ankle-high boots.", "837" ], [ "He has a fondness for bow ties and fezzes, proclaiming them as \"cool.\"\nThe details of the outfit vary, switching from a braces and bow tie combination in red to the same in blue. In later stories, a green military coat makes its way into the Doctor's ensemble, occasionally replacing the <PERSON> jacket.\nOn other occasions he does not wear a coat and wears a bow-tie and dress shirt. After the Doctor loses his original tweed jacket in the episode \"Flesh and Stone\" he replaces it with a plain brown jacket which he wears until the Christmas special \"A Christmas Carol\", which aired the Christmas after the eleventh Doctor's first series. In this episode the Doctor wears his most famous \"Prince of Wales check\" tweed jacket which he wears, with some switching to a green military coat, until parting ways with <PERSON> and <PERSON> in \"The Angels Take Manhattan\".\nAs to the red coat, Wikipedia says:\nIn \"Face the Raven\", the Twelfth Doctor sports a red velvet variant of his <PERSON> coat. After briefly ditching it in \"Hell Bent\", <PERSON> comments that it made him look more 'doctory'. At the end of the episode, he dons the red coat in honour of her, and is given a new sonic screwdriver by the TARDIS.\nSo depending on how he remembers <PERSON> in season 10, he may keep it as a reminder (although he hasn't done this with the other Companions as far as I know - and you'd think that because he was so attached to <PERSON> at the start he would have kept something).\nOf course it could be something of a midlife crisis as this article suggests.", "282" ], [ "The answer to this question is generally not a simple one.\nThe specific Q entity portrayed by <PERSON> has made references to the true nature of the Q and their existence starting from his first appearance in the TNG episode \"Encounter at FarPoint\"; that the human mind is not capable of comprehending the true nature of much of the universe (the crew's confusion about the nature of the events supports the theory).\nIn fact, every time Q appears something happens that is well beyond human comprehension and in one occasion the TNG crew find themselves in Sherwood Forest.\nIn the episode \"Deja Q\" <PERSON> character has been stripped of most of his abilities by the other Q and is struggling to understand what the beings he has been \"tormenting\" are actually capable of. He says to \"change the gravitational constant of the Universe\" as a solution to a problem because altering the universe, and all of the subspace and technology within it, is something that would otherwise have been trivial for a Q. Changing the universal constant, however, is well beyond anything Star Fleet and their understanding subspace can achieve so they attempt to change the moon's gravitational constant instead (Note that the Federation often alters the mass, inertial and gravitational characteristics by pushing the ship and its contents into a subspace state).\nIn VOY episodes such as \"The Q and the Grey\", the Voyager crew end up visiting the continuum and it is explained that the reason the continuum seems to be a re-enactment of the American Civil War (with Voyager nowhere to be seen) is that their human minds are not capable of understanding what is really going on so it merely appears in simplified terms (usually something out of Earth history).", "837" ], [ "By contrast subspace is depicted as a region through which space ships and other objects can travel (not wooded or desolate land in the limited human understanding). Further it is also referenced that the Civil War style weaponry that everyone is firing at each other are actually disrupting normal space and causing supernovae all over the place that are actually apertures into the continuum and that Voyager can only enter by flying through the Supernova that occurred in the aftermath (likely what the shield was needed for). I believe <PERSON> makes a reference that they should go nowhere near the actual business end of the weapons considering what it would do to a human if it can actually make him seem to \"bleed\".\nWhat the writers seem to be getting at here is an that there are a very limited number of effects that can actually be visually produced by any character (either in universe or by the show's special effects crew); whatever coincidence there are in appearances the Q are NOT using any method or concept known to the Federation nor is the continuum anywhere that the Federation would be able to name. The Q ARE however often seen appearing on ships within subspace (Deja Q, The Q and the Grey and several others) and capable of using subspace techniques and technologies to do what they desire should they so choose.", "963" ] ]

[ 10209, 1036, 2123, 1550, 4232, 7771, 4096, 10346, 8287, 10200, 5839, 6703, 1650, 4780, 8413, 5064, 4105, 5932, 27, 6262, 7664, 3247, 5236, 2094, 7043, 11132, 4203, 5515, 9197, 2851, 10401, 7346, 8438, 302, 6536, 3812, 11304, 3441, 2446, 4779, 844, 10328, 1925, 7142, 3025, 7744, 3699, 8231, 10858, 2117, 8233, 9256, 2332, 8364, 10156, 967, 3519, 10826, 8993, 3408, 11230, 6310, 3878, 5694, 2224, 7119, 9459, 3139, 1306, 662 ]

[ [ "Simple Arduino Pot Plant Soil Moisture Sensor\nIntroduction: Simple Arduino Pot Plant Soil Moisture Sensor\nArduino Pot Plant Soil Moisture Sensor\nI have been struggling with over watering of my indoor pot plants, especially succulents. To this end I decided to make a simple Soil Moisture sensor that can tell me when the moisture level of my pot is too high (over watered), too low or just right!\nSupplies\n* Capacitive Soil Moisture Sensor V1.2\n* WS2182b mini\n* 3D Printing Filament\n* Arduino\nStep 1: Step 1: Gather Your Components\nI have used an Arduino Leonardo (this is what I had on hand and this project would work with any type of Arduino).\nI soldered wires directly to the Arduino headers. Using the Schematic attached.\nThe Moisture Sensor will work correctly on any Analogue in pin and the WS2812B mini should work on many digital pins however in my case I used D2.\nStep 2: Step 2: Calibrate Sensor\nThe Principle behind the sensor used is that as the moisture content increases so too does the capacitance in the sensors circuit placed in the soil. To use the Capacitive Soil Moisture Sensor V1.2 we supply either a 5V or 3.3V power source (ideally a stable voltage source) we can then read an analogue voltage from the sensor that corresponds to the capacitance of the sensor and therefor the moisture level of our soil.\nGiven there can be variances between manufactures and even parts it is sensible to calibrate the sensor so it works for the specific sensor we have. This may not be 100% necessary however can improve the performance of your sensor.\nCalibrating the Sensor:\n1. Connect Sensor to computer running Arduino Script\n2. Open Serial Monitor (Arduino will output raw values from the ADC on the Arduino. Value between 0 and 1023)\n3. Note the value seen when the sensor is in the air\n4.", "152" ], [ "Submerge the sensor into water up to the point you would in your pot. Note the value seen while in the water.\nNow that you have noted the \"dry\" and \"wet\" value it is time to update the Arduino script with this information.\nGo to Moisture Sensor Setup in Line 19 and update AirValue and Water Value with those you have recorded.\n//Moisture Sensor Setup\nconst int AirValue = 900;\nconst int WaterValue = 680;\nStep 3: Step 3: Select Limits\nEvery plant is different! Some plants like a dry soil and prefer to be watered once and then left for a while. Others need moist soil almost contently and will need watered regularly. At this point we need to decide what we want to consider as over watered and under watered! This differs plant to plant.\nNote: The Arduino Script has some small logic to convert the reading into a percentage where 0% Moisture would be the value you recorded in Air and 100% Moisture being the value you recorded when submerged in water.\nGiven we are now working with percentages we need to pick a percentage Moisture we want to be alerted at when we need to water and one to know when the plant is over watered. Anything in between and the plant will be happy!\nThe table bellow shows the values I have found good for different plants. Comment what values have worked for your plants!!\nPlant Over Watered Percentage Under Watered Percentage Strawberry 90% 35% Butterfly Palm 85% 30% Aloe 70% 15%\nStep 4: Step 4: Print the Case and Assemble\nI 3D printed the case for the sensor to hold it in a small and simple box. I wanted something slim so decided to only use the moisture sensor however with some further work and the inclusion of a simple Light Dependent Resistor this design could be extended to make sure your plants are getting the correct amount of light.\nThe 3D files for the case can be downloaded from Github.\nOnce printed it is time to assemble! You should have the Arduino, sensor and LED soldered together. Now place the LED into the recess hole and the moisture sensor in its location. Place the cover on top and glue in place (I used Blu-Tack).\nStep 5: Step 5: Be the Perfect Plant Parent\nThe LED have three colours to show you the Moisture in your pot!\nSee the table bellow to know what the sensor is saying.\nBlue Over Watered Green Happy Plant Red Needs Water", "33" ], [ "Motion Trigger Circuit With and Without Microcontroller\nIntroduction: Motion Trigger Circuit With and Without Microcontroller\nGreetings\nHere's a tutorial on how to use an HC-SR505 PIR Module with and without a microcontroller to drive XYZ Load when any motion is detected.\nThis Tutorial contains three different types of setups that we can use to prepare a Motion Detection Based Project like an automatic Hallway Light or Motion Detection Security System Etc.\nLet's get started.\nSupplies\nFollowing are the materials used in this built-\n* PIR HC-SR505 Module\n* Attiny13A\n* TTGO T Display Board\n* LEDs\n* Jumper Wires\n* BC547\n* Breadboard\n* USB Micro Port Breakout board\nStep 1: HC-SR505\nHC-SR505 is a PIR Sensor that picks up infrared radiation emitted by the body and then outputs a signal based on the motion of a body.\nYou see, as we move, our body emits more and more infrared radiation that is picked up by this sensor.\nFollowing are its electrical parameters and features-\n* Operating Voltage Range: DC4.5-20V\n* Static current:<60uA\n* Output level: High 3.3V / Low 0V\n* Trigger: repeatable trigger\n* Delay time: Default 8S + -30% (can be customized range of a few tenths - tens of minutes)\n* PCB Dimensions: 10 * 23mm\n* Induction angle:<100 degree cone angle\n* Induction distance: 3 meters\n* Working temperature: -20 - +80 degrees\n* Sensor Lens Dimensions: Diameter: 10mm\nStep 2: PCBWAY GIFTSHOP\nAs for sourcing the HC-SR505, I got it from PCBWAY's Giftshop.\n Aside from PCB Services, PCBWAY also has a dedicated components store.\nPCBWAY GIFTSHOP is an online marketplace from where we can source all the major electronics stuff, like Arduino boards, Raspberry Pi boards, Modules, sensors, etc.\nPCBWAY have this system that lets us purchase anything from their gift shop through beans, Beans are like a redeemable currency or coupons that we get by placing an order on PCBWAY or by sharing your projects in the community to get beans.\nCheck PCBWAY out for getting great PCB service from here- https://www.pcbway.com/\nStep 3: First Setup- Basic One\nTo Prepare the first Setup, we provide VCC and GND of this module with 5V.\nWe add an LED's VCC Pin on the signal Pin of this module and connect the GND of the LED with the GND of the Module.\nThis will be the first and most basic Setup we can prepare with this module.\nJust by standing near this sensor, It turns ON the LED, LED will stay ON for 8 seconds and then turn OFF, if we are near the 3M Radius of this module, the LED will turn ON again.\nStep 4: With Microcontroller TTGO T Display\nHere's the second setup that uses a TTGO T Display board to Turn ON and OFF an LED and also display a message when motion is detected on its onboard RGB Display.\nStep 5: Preparing TTGO Board for Arduino IDE\nWe first have to install board files for ESP32 by putting this link in the preferences of the Arduino IDE Settings and then installing the boards through the board manager.\nhttps://dl.espressif.com/dl/package_esp32_index.json\nStep 6: Installing TFT_eSPI Library and Making Changes in User Setup\nWe then move on to the next step which is to install the TFT_eSPI Library that enables us to use the display onboard.\n* Next, we go to C:\\Users\\ACER\\Documents\\Arduino\\libraries\\TFT_eSPI and make changes in the User Setup.h by replacing it with User setup for TTGO T Display.\n* The default one is set for ILI9430 Display and we change it for TTGO T Display by adding // in front of ILI9430 User setup and removing // in front of TTGO T Display.\nStep 7: Connections - Wiring\nnext, we connect everything by following the attached wiring diagram image.\n* VCC of PIR to 5V of TTGO\n* GND to GND\n* Signal Pin of PIR to D22\n* LED's VCC to D21\n* LED GND to GND\nStep 8: Sketch for TTGO\nHere's the code we use.\n#define sensor 22\n#define LED 21\n#include <TFT_eSPI.h> // Graphics and font library for ST7735 driver chip\n#include <SPI.", "982" ], [ "How to Control Any Drone From Your Arduino Microcontroller Using Bluetooth\nIntroduction: How to Control Any Drone From Your Arduino Microcontroller Using Bluetooth\nHello Everyone!!!\nIn this Instructable I am going to show you how I converted my (Commercial) RC drone that uses an RC radio system into a drone that is controlled by your Arduino using Bluetooth\nWhy would I want to control my drone from an Arduino?\nI wanted to control my drone from an Arduino because I wanted to take a step into the automation of my drone. There was the option of building a drone and using the Arduino as the Flight Controller, but then I would miss out on all of the advanced features that the more popular firmware, like Betaflight, provides. This led to me thinking, \"Why not replace the receiver of the drone with an Arduino, that way you still control the drone from your Arduino and you don't have to compromise on its performance\". That was the idea, so let's see how we did it.\nSupplies\nThis is a list of all the main supplies needed for this project:\n* Arduino Uno\n* HC-05 Bluetooth Module\n* A Drone - I built my own FPV drone. Make sure the Flight Controller supports the PPM protocol and it supports Betaflight.\n* A drone battery\n* PCB Board\n* Arduino IDE\n* Betaflight Configurator\n* A phone that supports bluetooth.\n* A Micro-USB for data transfer\n* 10k Potentiometer (Optional but recommended)\nThis is a list of all of the tools needed for the project:\n* A soldering iron\n* Soldering wire\n* Wire strippers\n* Electrical Wires (Male - Male and Female - Male)\n* Multimeter (One that has a continuity tester on it)\n* Electrical Tape\n* Precision Screwdriver Set\nStep 1: The Theory and the Idea\nThe Theory\nThe theory behind this project is to use PPM signals which will be generated by the Arduino to control the drone. The Flight Controller usually receives PPM signals from the receiver which receives data from the transmitter. If we can generate the same PPM signals that the receiver sends to the Flight Controller with the data from the transmitter, we can encode our own data onto the PPM signals from the Arduino and control the drone from the Arduino. This means that a conventional transmitter and receiver is no longer required to pilot the drone and we can use any method of input to control the drone.\nWell what are PPM signals?\nA PPM signal (or Pulse Position Modulation) is used by most transmitters and receivers to transfer information from the transmitter to the receiver.\nPPM is a single-wire signal that encodes many Pulse Width Modulated (PWM) signals. It's commonly used in radio control of hobby aircraft and drones, where a radio transmits the PPM signal, which is decoded into many PWM signals to control RC servo motors.\nThe signal that is sent is a series of pulses of fixed length, which are measured in microseconds . In electronics these pulses are an electrical signal of varying voltage (somewhere between +2.5V and +5V seems to be normal).Between these pulses are pauses of varying length (also measured in microseconds).", "120" ], [ "In electronics these pulses are somewhere between 0V and +0.5V.\nThe data on this type of signal is encoded as the length of a pulse plus the length of the following pause. Or in other words: the time between the start of two pulses (or end, doesn't matter since the pulse is of fixed length). This is also the reason it doesn't matter whether the pulse is high or low; you simply pick either the rising or falling edge of a signal and measure the time between two rising or falling edges.\nChannels follow each other in chronological order in the signal; i.e. channel 1 comes first, channel N last. The time between the pulses is used to generate a Servo Signal (in our case this signal will not control servos, but rather the motors on the drone). Pulses are usually around 500 microseconds in length (but as you will see in our case, the length might not always be 500 microseconds), the pauses are somewhere between 500 and 1500 microseconds. When you add those together and you get channel values of 1000 to 2000 microseconds, which happens to be the same range as used in Servo Signals.\nAfter the last channel there's an End Of Frame (or Beginning Of Frame) pause. This pause is somewhere between 5000 and 20000 microseconds in length; receivers don't seem to be very strict with this. The pause may be of varying length, this way you can set a frame to a fixed length. Bear in mind that the longer the pause, the more latency you will experience, but the shorter the pause, the more unstable the communication will be between the Arduino and the Flight Controller.", "71" ], [ "Make Your Own Arduino AC Dimmer | Drive Motors & Lights\nIntroduction: Make Your Own Arduino AC Dimmer | Drive Motors & Lights\nHi every one, here <PERSON>, and I want to show you how I made my own Arduino AC dimmer that can control AC loads such as motors and lights easily. It has the power to handle 1200+ Watts and It's a very nice project for domotics and home automation because the microcontroller I used is the ESP8266 that has WiFi capabilities and the code could be adapted with few changes.\nHere I leave you a tutorial with all the information so you can make your own version.If you are a visual learner I know that a video worth more than 1000 words, so here is a Tutorial video. (I am a Spanish speaker, so please consider turning on English subtitles):\nStep 1: Skills Required:\nThis project may seem difficult or very complex, but it is definitely not completely, since you will have all the guidance for the construction, it was difficult for me to design it to make life a little easier for you.", "382" ], [ "Any conceptual doubt, you are free to ask it without problems.\n* You should have an understanding of:\n* 3D Printing (Optional for the case).\n* Arduino programming (I give you the code).\n* Soldering through hole components.\nWarning: In this project we will handle main power, so please be careful\nStep 2: Components and Parts List\nThe Electronics discrete components as resistors and transistors will be attached in a BOM file in the PCB Step.\n* Here is the list of what you will need for the whole process:\n* -10kohm Potentiometer.\n* -2 Double Terminal blocks.\n* -AC motor of your preference (single phase).\n* -Dimmable Lightbulb.\n* -Small 5 volts cellphone power supply.\n* -Measuring tools: multimeters, clamp meters (optional).\n* -Micro USB SMD connector.\n* -1.3 inch OLED Display.\n* Wire.\nBOM list of PCB components attached.\nGreat, cheap and awesome Graphical Multimeter to watch the Sinusoidal AC wave form\nStep 3: Circuit Diagram\nHere is the Circuit Diagram of our project:\nIt has all the internal conections of the circuit that will us allow to create the PCB design later.\nI also attached the PDF of the Schematics so you can see it better.\nStep 4: PCB Design and Ordering\nFor the implementation of a good project we need a reliable assembly for the circuit that makes it up, and there is no better way to do it than with a good PCB.\nHere you can download the Gerber, BOM and Pick & Place Files, the ones you need to order your PCB on your PCB manufacturing company.\nI suggest JLCPCB:\n$2 for 1-4 Layer PCBs⚡, Get SMT Coupons🎫\nUnZip the .rar file with a software like WinRar or any other.\nStep 5: 3D Parts (Housing + Motor Holder)\nHere you have the STL files for the 3D parts of the project.\n* Housing.\n* Cover\n* Potentiometer Knob and nut.\n* Button cap.\n* Motor holder.\nStep 6: Programming the ESP8266 Microcontroller\n1- To program the ESP-12s we need to connect it directly to our PC through the USB cable, open the Code \"ACControl\", install the libraries that I also attached and click on upload.\nIf the current measurements are wrong on your display, or you want to improve them, you can tune experimentally this parameters in the code:\n* float Sensibilidad = 0.066; //sensitivity of the 30Amps sensor (see datasheet of ACS712 if use 20A or 5A version).\n* float intercept = 35952.685; // Change this until you got closer as posible to the real current.\n* float slope = 273; // Change this until you got closer as posible to the real current.\n* float testFrequency = 60; // frequency of your circuit (Hz)\n* float windowLength = 40.0 / testFrequency; // num of cycles that will be test.\nCODE, LIBS, EVERYTHING, DOWNLOAD FOR FREE HERE\nStep 7: Wiring Up\nFollow this few steps carefully:\n1. Insert the OLED Display in the case slot.\n2. Wire the Display and make shure the connections are right between the PCB and OLED (Pinout may vary).\n3. Connect the motor or light wires (Black and Red) to the output terminal block, it doesn't matter the polarity.\n4.", "472" ], [ "Attiny13A Motor Controller Board\nIntroduction: Attiny13A Motor Controller Board\nHey Guys how you doing!\nSo here's something super interesting and useful, a motor controller board powered by an Attiny13A to control a Brushed DC Motor.\nThis Motor Driver uses PWM to control the gate of an N Channel IRFZ44N mosfet by the Tap of a single button.\nI've added Two Modes in the code that basically controls the Duty Cycle, On First Tap the setup turns ON at 100% Duty cycle, then on the Second Tap, the Duty Cycle is half at 50%. The third Tap turns the whole setup OFF.\nI made this Motor Controller board for a future project that is a Bladeless Fan Project that I will soon publish.\nThis Instructables is about the whole building process of this Motor Controller so let's get started!\nSupplies\nFollowing were the materials used in this project-\n* Attiny13A\n* Custom PCB\n* Brushed DC Motor\n* IRFZ44N\n* AMS1117 5V\n* 10K Resistor\n* 1uf Capacitor\n* 10uf Capacitor\nStep 1: SCHEMATIC and PCB Design\nThis Schematic is a simple one, there's an N Channel Mosfet that is configured in \"Mosfet as Switch setup\". This means the gate of Mosfet can be used to power the load which is, in this case, a DC Brushed Motor.\nThere are two Resistors connected to the Gate of Mosfet, one is connecting the gate with GND and another one is connected to the D0 Pin of Attiny13A.\nI've used an Attiny13A to control the whole setup by using a Switch that is connected to the D4 pin and GND. By connecting D4 Pin to GND, Microcontrollers read this and provide the gate of Mosfet with a PWM signal that controls the gate of mosfet and the speed of the motor.\nNow, the motor that I'm using works at 12V and above but the microcontroller needs 5V Input so to step down 12V into 5V for MCU, I've added an AMS1117 5V Voltage Regulator.\nAs for programming pins for Attiny13, I haven't added any.", "982" ], [ "Because I'm using the DIP version of attiny and I'm planning to flash attiny with my Attiny programmer that has DIP Socket for flashing the MCU.\nI finalise the Schematic and prepared the PCB according to the PCB Outline that is required in my BLADELESS FAN Project.\nStep 2: Getting PCBs From SEEED Studio\nAfter finalizing the PCB and generating its Gerber data, I send it to SEEED STUDIO for samples.\nOrdered PCBs in Yellow Soldermask with white silkscreen.\nI received PCBs in a week and their quality was super good considering the rate which was also pretty low.\nSeeed Fusion PCB Service offers one-stop prototyping for PCB manufacture and PCB assembly and as a result, they produce superior quality PCBs and Fast Turnkey PCBA within 7 working days.\nPCB Quality of this Motor Controller PCB WAS SUPER!\nSeeed Studio Fusion PCB Assembly Service takes care of the entire fabrication process from PCB manufacturing, parts sourcing, assembly, and testing services, so you can be sure that they are getting a quality product.\nAfter gauging market interest and verifying a working prototype, Seeed Propagate Service can help you bring the product to market with professional guidance and a strong network of connections.\nStep 3: PCB ASSEMBLY\nPCB Assembly of this project consists of four major steps which are\n* Solder Paste Dispensing Process\n* Pick & Place Process\n* Hotplate Reflow\n* Adding THT Components\nStep 4: Solder Paste Dispensing Process\nWe start first by adding Solderpaste to each component pad on the bottom side of the board.\nStep 5: Pick & Place Process\nThen we pick and place each component in its assigned place one by one.\nStep 6: Hotplate Reflow\nNext, we carefully lifted the whole PCB and place it on the hotplate. I’m using my good old DIY hotplate which I made a while back.\nHotplate Heats the surface up to the solder paste melting temp and it slowly melts. after a few mins when the solder paste completely melts, we remove the PCB and let it cool down for a moment.\nStep 7: Adding THT Components\nHere's the final setup, we place the remaining two components which are DIP Socket and Mosfet. However, we also add an SMD LED on the Top side with a soldering Iron as well, we cannot use a hotplate for placing the LED as we already place stuff on the Bottom side and this hotplate method is applicable for one side only.", "472" ], [ "DIY SMT Hotplate Project\nIntroduction: DIY SMT Hotplate Project\nHey Everyone what's up!\nSo this is my \"DIY SMT Reflow Iron\" made from Cloth Iron Element screwed onto a thick copper plate to transfer heat for achieving the desired heating which would be the correct melting temperature of Solder paste (which is in my case 270°C)\nThe goal for making this DIY SMT Reflow was simple, it's easy and cheaper to make a working SMT Reflow Hotplate instead of buying a proper hotplate.\nVideo-\nSupplies\n* Iron's Element 700W-1000W (I'm Reusing this from an OLD Iron)\n* Copper plate 150mm x 250mm x 2.2mm\n* Wooden Board 460mm x 380mm x 20mm\n* M4 Screws 50mm Length\n* M4 Bolts\n* AC Cord\n* ESD Mat 145mm x 345mm\nThe rest of the parts are for Preparing the Temperature sensor.\n* PCB (Which was Provided by JLCPCB)\n* OLED Display SSD1306\n* Atmega328PU\n* 16MHz Crystal\n* 22pF Cap 0603 Package\n* 10K Resistance 0805\n* NTC 10K\n* 5V 1A Charger Circuit\n* 3D Printed Enclosure/BOX\n* Potting Compound (Epoxy and Hardener)\n* Teflon wires RED, Black, White\n* PCB for Reflow\n* Solder paste\n* Arduino as ISP Programmer setup\nStep 1: Little About Solder Paste\nThe Melting Temperature of solder paste depends on the Flux percentage and the ratio of Sn-Pb which in my case is 63/37, Sn63-Pb37.\nSn-Pb solder has melting points from 140 to 270 °C higher.\nNote- I bought this Solderpaste without checking the Melting temperature. Solder paste with a lower melting temperature should be used. (170-200°C)\nStep 2: Basic Setup\nThe hotplate is powered Directly from the AC Supply, no Relay has been added to the hotplate line for power cutoff or Control.", "472" ], [ "The reason for this is pretty simple, adding Relay to this setup means we need to monitor the temperature and cut the supply of Hotplate whenever the hotplate reaches a certain temperature and then reconnect when hotplate temperature goes down.\nOn the Iron's Element, there's a mechanical part in iron which is the thermostat.\nThe thermostat is an important component of an electric iron that regulates its temperature, when Iron reaches a certain Temperature, the Thermostat turns off the power of iron. This mechanism consists of a bimetallic strip that is made from Brass and iron, when the temperature of the iron exceeds a certain limit, the strip begins to bend towards the metal with a lower coefficient of expansion. As a result, the strip ceases to be physically connected to the contact point, the circuit opens and the current ceases to flow.\nyou should definitely check out this great article about the working process of iron from here for more detail about the Iron's working!\nSo the bottom line here is that the iron already has a Power Cut Off circuit that controls the temperature of Iron, we only require a Temperature monitoring setup that displays the accurate temperature of the Copper surface.\nFor measuring Temperatures higher than 150°C, I Prepared an NTC Based Atmega328PU Setup which displays the Hotplate Temperature on an SSD1306 OLED Display.\nStep 3: Preparing the Temperature Sensor Setup\nIn Order to Make this temperature Sensor Setup, I used a 10K NTC along with an Arduino Nano to set up a basic Temperature Sensor setup by following this Guide.\nSetting up NTC is pretty easy, we just need to add NTC with the same Value resistance (in my case 10K) in series with the NTC according to the given schematic.\n* After Finalizing the Breadboard version, I prepared a Minimal Atmega328PU Setup by using a PCB from a different Project.\nPCB that I'm using here was from a Different project which was this-\nhttps://www.instructables.com/Arduino-Based-Synth-With-Mozzi-Library/\nI prepared the PCB in a PCB designing software and then gave this PCB to JLCPCB for samples!\n* I first added the necessary SMD components to the PCB which were mentioned in the schematic above.\n* Now, the PCB that I'm using doesn't have a breakout point for OLED Display, so I modified the PCB a little bit by cutting the copper traces of Four connectors and then I added VCC, GND, A4, and A5 Pins separately to that connector by jumper wire.\n* after that, I added THT Components like the IC and burge strip.", "472" ], [ "Smart Desk LED Light | Smart Lighting W/ Arduino | Neopixels Workspace\nIntroduction: Smart Desk LED Light | Smart Lighting W/ Arduino | Neopixels Workspace\nNow a days we are spending a lot of time at home, studying and working virtualy, so why not to make our workspace greater with a custom and smart lighting system Arduino and Ws2812b LEDs based.\nHere I show you how build your Smart Desk LED Light that you can control with an IR remote controller from your TV, Home theater, or any device with IR transmitter.\nIf you are a visual learner I know that a video worth more than 1000 words, so here is a 2 parts Tutorial video. (I am a Spanish speaker, so please consider turning on English subtitles):\nStep 1: Skills Needed\nAs you can noticed, nothing looks very difficult on this project, but you will need some basics knowings about:\n-Using the Arduino IDE.\n-Programming ESP8266.\n-3D printing.\n-Welding.\n-Wiring.\nStep 2: Components and Parts List\nA good place I can recommend to find your components, it's MakerFocus, it's an Open Source Hardware Store!\n1. PCB I really recommend to use JLCPCB SMT Services to order yours.\n2. ESP8266 (Microcontroller).\n3. WS2812 LEDs Strips.\n4. 5v 2A Power Supply.\n5. PCB Power Jack.\n6. 3D Printer.\n7. IR Sensor\n8. Remote controller, could be your TV one.\nStep 3: Circuit Diagram\nHere is the Circuit diagram, it has all the internal conections of the circuit that will allow us to create the PCB design later.\nI also attached the PDF of the Schematics so you can see it better.\nDOWNLOAD Schematics, Code and Libraries for FREE.\nStep 4: PCB Design and Ordering\nFor the implementation of a good project we need a reliable assembly for the circuit that makes it up, and there is no better way to do it than with a good PCB.\nHere you can download the Gerber, BOM and Pick & Place Files, the ones you need to order your PCB on your PCB manufacturing company.\nI suggest JLCPCB:\n📦$2 for Five - 4 Layers PCBs & cheap SMT (2 Coupons)\nBUY THE ALREADY DESIGNED BOARD, Gerber + Pick & Place + BOM\nStep 5: 3D Parts Printing\nAll the files to print the project enclosure.\nYou can print them on your 3D printer, if you haven't got yours, here you can by the one I use.\n3D Printer Ender 3 Pro\nStep 6: Programming the ESP8266\n1. Install the Libraries that will the code works\n2.", "382" ], [ "Open your Arduino IDE.\n3. Go to File > Examples > IRremoteESP8266 > IRrecvDemo\n4. This example Code will let you copy the IR code that transmits the remote controller key you want to use.\n5. In the IRrecvDemo, update the kRecvPin to the one you have connected with the IR Sensor.\n6. Connect your ESP8266 to the programmer and connect the IR Sensor to your selected Pin.\n7. Upload the code.\n8. Open the Serial monitor and press the keys you want to know the code, and copy and save them on notes.\n9. Open the MCM-LED-DESK.ino code.\n10. Set the kRecvPin to 3, the pixels are connected on pin 0 and the pixels count in my case is 80.\n11. In the Leer() function, update the code of the If's to the ones of your remote controller.\n12. Upload the code to the ESP8266 using the project PCB and a USB to TTL converter\nStep 7: ESP8266 ADC Hack\nAs you noticed, my design can be used with a ESP-07 or ESP-01, but in my case I used the ESP-01 and it doesn't have the ADC (Tout) pin reachable so I had to solder a tiny wire in the Tout pin of the chip and connect it on the PCB ADC pin.\nStep 8: Project Assembly\nPlace the PCB with everything connected already in the box, screw it, place the potentiometer nut and knob, glue the IR sensor and close everything with screws or more glue :D.\nStep 9: Placing the Strips and Control Unit\nGlue the Strips on your desk or desired place, they already has glue but I secured them with some hot glue.\nCut it at your desk/place size, be sure the connector can reach the control box and glue it too.", "977" ], [ "Arduino - How to Read SD Card Text File Line by Line\nIntroduction: Arduino - How to Read SD Card Text File Line by Line\nIn this tutorial we will learn how to read the SD card text file line by line.\nWatch the Video!\nNote: You can use other Displays such as OLED, but make sure that you use a board with enough memory like Arduino Mega,etc\nAlso check out this tutorials:\nArduino Nano: Measure Distance With Ultrasonic Ranger and Log It to MicroSD Card With Visuino\nArduino Nano: Log GPS Information to MicorSD Card With Visuino\nStep 1: What You Will Need\n* LCD Display I2C 20X4 (if you use diferent LCD then make sure that you specify the right Columns and Rows in the Visuino component)\n* SD card module + SD card\n* Jumper wires\n* Arduino UNO or any other board\n* Visuino software: Download here\nStep 2: Start Visuino, and Select the Arduino UNO Board Type\nThe Visuino: https://www.visuino.eu also needs to be installed. Download Free version or register for a Free Trial.\nStart Visuino as shown in the first picture Click on the \"Tools\" button on the Arduino component (Picture 1) in Visuino When the dialog appears, select \"Arduino UNO\" as shown on Picture 2\nStep 3: Prepare the SD Card\nOpen a Notepad or any other writing software on your computer and write it like this:\nTEXT LINE1\nTEXT LINE2\nTEXT LINE3\nTEXT LINE4\nThen save it as a \"TEST.TXT\" to the SD card. Remove the SD card from your computer and put it in the Arduino SD card module.\nStep 4: Circuit\n* Connect SD card Module pin GND to Arduino pin GND\n* Connect SD card Module pin VCC to Arduino pin 5V\n* Connect SD card Module pin SCK to Arduino digital pin 13\n* Connect SD card Module pin MISO to Arduino digital pin 12\n* Connect SD card Module pin MOSI to Arduino digital pin 11\n* Connect SD card Module pin CS to Arduino digital pin 10\n* Connect LCD Display pin VCC to Arduino pin 5V\n* Connect LCD Display Module pin GND to Arduino pin GND\n* Connect LCD Display pin SCL to Arduino pin SCL\n* Connect LCD Display pin SDA to Arduino pin SDA\nStep 5: In Visuino Add Components\n* Add \"Micro SD Card Module\" component\n* Add \"Liquid Crystal Display (LCD) - I2C\" component\n* Add \"Start\" component\nStep 6: In Visuino Set Components\n* Double click on the \"SDCard1\" component and in the Elements window drag \"File\" to the left side\n* Now on the Left side of the Elements window select \"File1\" and in the properties window set \"New Line\" to False, \"Path Name\" to TEST.TXT\nand select \"Elements\" and click on the 3 dots button, a New Elements window will open, here drag 4X \"Read Text Line\" to the left side.", "991" ] ]

[ 3418, 8890, 7707, 2263, 9849, 2430, 3390, 8514, 4445, 6660, 9743, 2841, 5107, 3296, 11429, 1968, 807, 7678, 2177, 10327, 3507, 2716, 11138, 5232, 6486, 4166, 3024, 3359, 7870, 1128, 10714, 3907, 2515, 10693, 2405, 1609, 3369, 10012, 1389, 5744, 9367, 11394, 9840, 8879, 9922, 8074, 6222, 4066, 865, 3670, 1564, 9886, 8841, 1884, 5075, 8550, 10746, 3074, 4110, 2198, 3005, 4653, 837, 6614, 10377, 4495, 3547, 6756, 5944, 9042 ]

[ [ "Given that humanity has evolved from what we believe were such species, I would expect that any such society would not be as successful as ours. We evolved our current forms of sexuality precisely because they were more successful.\nIn your description of human sexuality you miss the most important factor behind the vast majority of human sexual activity - it is an important part of human pair bonding. Recent studies suggest that when it comes to conception women are actually programmed to seek very different partners to those they would form a relationship with. Even at a base, instinctual level almost the entirety of the sexual activity within this relationship is motivated by the desire to bond and form a closely knit unit, and not to conceive. Without this \"recreational\" sexual activity, it is unclear to what level male/female relationships would develop. Without the support of such a relationship, new and expectant mothers may face significant difficulty.\nIn humans, as compared with other species, the male and female are remarkably equivalent in the overwhelming majority of qualities and abilities. However, relative to other species, human pregnancy is especially restrictive - a heavily pregnant cow is not nearly as restricted in its movement as a heavily pregnant woman. Worse, excessive exercise during pregnancy is heavily associated with miscarriage - and strenuous agricultural work would be more so. This means that for a period of time a pregnant woman will contribute less and demand more. Also, human newborn are unusually helpless for an unusually long period of time - it is perhaps 4-5 years before they have any real hope of fending for themselves, and much, much longer before they have a good chance.\nNow, it is possible that a woman will be sufficiently supported by her family or wider society, but there are difficulties here.", "1008" ], [ "Firstly, in an early agrarian society life expectancy is short and mortality at all stages of life, especially infancy, is high. Even in our own world, the typical response to high infant mortality is a higher birth rate. Families will most likely be very broad but lack depth. Relative to modern families there will be fewer elderly relatives per young child, less attention to go around, and less spare capacity in the system to support them. The \"dreadful algebra of necessity\" creates a kind of terrible paradox for children - they are both loved and unwanted, both essential and disposable. In our own world, impoverished children have had a terribly bad lot in life and most societies throughout most of history have done very little to help. It seems unlikely then that a pregnant woman or new mother, unable to depend on the father, could reliably depend on significant support from society. Furthermore, by limiting the development of pair bonding, any \"family\" will be restricted to female ancestors and their descendants (of both sexes). Realistically, extended families will comprise somewhere between a quarter and a half of the individuals that would have been included in a pair bonded society.\nIn a bronze- to iron-age society, I would expect all of this to dramatically increase the depth and duration of periods of poverty and hardship, exacerbating food shortages and severely limiting the supply of surplus labour that could be turned to technological development.\nAs for modern society suddenly catching the disease, I have far fewer fears. With the high levels of social security enjoyed by modern civilisation, established charitable organisations and well developed systems of state support, society would largely continue unchanged. There would probably be increased pressure on housing as people lived separately rather than together, but otherwise we know that single parents and their children are able to live very good lives.", "998" ], [ "It does seem difficult to avoid the conclusion that this world must be a single political unit with oddly defined member states. If you dig in on each country being a fully independent state I can't think of any good reason people would naturally come to regard borders in this fashion, or even continue to regard borders in this fashion for any considerable length of time if they were simply assumed to regard borders in this fashion by hypothesis. Interstate conflict, if permitted, would soon disrupt border definitions. So, to maintain the stability of the concept of countryhood, interstate conflict must somehow be suppressed, likely by an overarching world governmental authority. Then the story would be that this is just how the world government organizes itself, community laws in a spot being governed by those geographically in the community of that spot. Countries are the top level communities of radius 300 km. Perhaps there are also lower-level communities with smaller radii that define laws or ordinances within the sphere of authority determined by the overarching authority. (For example, countries might legislate the definition of violent crimes, but obscenity law could be the purview of \"cities\", communities of radius 30 km.) The effect would be a spectrum shift in law as you move from one place to another. A short drive might offer a bounty of legal pornographic filth, or freedom from the temptation of its open sale, but you'll be driving for quite a while to find a country where the knockout game is a felony instead of the national sport or vice versa.\nHaving leaders for an undefined number of countries would be tricky, so I think the main two options are direct democracy (with a location's laws being determined by the past votes of voters within the community radius) and autocracy (everyone is dictator of beneath their own feet for life!) The autocratic option is only stable if the power of countries is very, very strictly limited, as it is difficult to see how the countries would not be in constant conflict.\nStill, I am intrigued by the question as you posed it, and I think we can get an interesting picture by borging up the population a bit.", "274" ], [ "Give everyone a neural implant that implements the geographic direct democracy in real time. If your implant can only communicate with implants within 300km, 300km is the radius of your country. Interestingly, if we can rule out long range missiles and remote drones, this also eliminates the possibility of international conflict without the need for an overarching supernational authority. If you have to get within 300 km of someone/something to attack them/it, there simply are no available international targets. Sending a bomber or soldier into rival territory can only be a transfer of citizenship and equipment. International relations are effectively limited to trade (by relay or immigration) and teleconference.\nI don't think immigration controls as borders could be a thing, everyone would wind up effectively frozen in place (you don't have to move very far to cross SOME border), but you might wind up with prices of entry to move a particular direction. \"If you're coming this way, bring copper.\" \"If you're coming this way, bring food.\" With the neural implant direct democracy, this would be easy. People in food impoverished countries know they're hungry, and their neural implants vote to not allow people in without food. (Hopefully you can check the laws of a destination before departing even if your neural implant cannot directly communicate with the implants there.) Global trade would become very efficient.", "207" ], [ "To extend <PERSON>'s answer... a few things off the top of my head in no particular order. Most of these apply to lower technology human societies where modern technology hasn't compensated for biological differences.\nHumans lack fur because we hunt by running. Humans can out run any animal on earth.\nIt's people without horses catch horses. They jog after horses, never catching them but never letting them rest either. After about 20-25 miles at most, the horse can't run any further, the human walks up and puts a rope arounds it's neck.\nWith flint, wood and bone weapons, hunters wound prey and then run it into the ground.\nIt's hard to cool by sweat with fur. If you ever seen a horse, \"lather up\" you've seen the basic problem. Horses have very thin, fine, close knapped fur yet still it interferes significantly with evaporation.\nSo, first off, humans with fur would have evolved to hunt differently. Likely, we would hunt with traps or with in larger groups like wolves. In either case our entire physiology might shift. We'd be adapted to sprint horses or wolves, to catch game quickly.\nOne affect might be a decrease in sexual dimorphism (overt differences in body shape by sex.) Part of the difference between men and women can be attributed to men being more adapted to protracted exercise. Distribution in muscles, muscle recover time, more sweat glands etc all point to optimization of men for running. If such optimization were not needed, then men and women might be more similar in physiology just like wolves and other canines and just like wolves, there would be less specialize of labor and less specialization in behaviors.\nMost sexually monomorphic species are matriarchal, with the entire group supporting the reproduction of the matriarch, at least in hard times. Human society might be radically different historically although we might start out with something like we have now after technology has leveled the playing field between men and women.\nWe likely would have had trouble with prolonged relative work like most pre-industrial agricultural work. Humans have to be careful not to kill horses and oxen by forcing the animals to work as long as humans do. We would adapt society to allow working in sprint shifts, with two or more individuals tag teaming a single job to keep the work going. If men and women where physiologically similar, they could swap off child care and work for everything except nursing.\nIndividuals might commonly pair up with siblings, other relations or friends for life, both specializing in the same job and together forming a complete work team.", "802" ], [ "So, if someone was a blacksmith, their partner would be as well. People didn't have time to waste so individuals would have some secondary task to occupy them at a lower level of effort while they rested from the main task. Human social structure would be based on this partnership. It would affect everything from military units to marriage.\nHumans would be less mobile in general, at least preindustrial. Unable to walk, march or run as far, they would have to adapt activities to being closer to home. Any systems based on walking, like cities, would be more compact.\nArmies would march and move slower but move faster in battle itself owing to likely greater sprinting speed. Battles would have to be decided faster before exhaustion set in. Battles would be very intense but short. This would favor more organized forms of shock warfare, like Greek Hoplites. The idea would be to hit the enemy hard and fast and do maximum damage in the shortest amount of time. Alternatively, there would be more pressure to develop a rotational system like the Romans used to grind away at an enemy while preventing exhaustion of individuals.\nIf the pair system did evolve, that would be part of the military as well and if men and women were more physiologically similar, then women would participate in combat more. If women could fight, that would increase per capita fighters in the population. Combined with intense shock warfare, battles could be more devastating with more adults overall in a population likely to be killed.\nSlavery might be more difficult both in terms of the danger of going to war to capture slaves, the added difficulty in controlling women and the inability to substitute humans for animals and machines in many circumstance e.g. treadmills. Managing slave work would be more difficult if slaves had to constantly swap out task.\nHaving fewer slaves would likely reduce the profitability of war (slavery being a huge driver of warfare in classical times.) It would also foster technological development because it would be difficult to solve a complex problem just by throwing more slave at it e.g. threshing grain or grinding flour.\nThere would be greater pressure to domesticate animals for transportation and labor and greater pressure to develop vehicles and machines. Riding animals and carts would be more common of basic necessity which would make it harder to restrict horses to military caste aristocrats.", "238" ], [ "My answer is to apply monetary economics. I shall assume that technological or bio-technological solutions to increase the ability of the planet to dispose of significantly more waste heat than it does today are not feasible or desirable.\nSecondly, with all that MF power, lets get people making use of it to develop a spacefaring civilisation!\nSo my recommendation to the commission is roughly as follows:\n1. The (world) government shall establish a currency for which one unit can be redeemed against the rights to operate a MF that produces one unit of waste heat. This is similar to todays money which is redeemable against future consumption - now we explicitly tie money to entropy production. This currency replaces the current fiat system. Money based on energy usage has been quite widely discussed in the context of peak oil. This situation is essentially the same.\n2. The quantity of currency is fixed according to the capacity of the earth to dispose safely of the waste heat, so its different to todays money in which the economy is not energy constrained is is more constrained by supply and demand of finished goods.\n3. The government mandates that FI with their fantasticly secure technology that cannot be reverse engineered add a 'waste meter' to each MF that is loaded with the credits/money and will refuse to produce power when the credits run out.\n4.", "852" ], [ "These constraints do not apply for MFs used off-world, and this stimulates movement of power hungry manufacturing processes, and in time, residential establishments to move off world. Asteroids and comets are fetched to power the off world MFs. Since the off-world economy is not energy constrained, it uses its own forms of private currency similar to modern bank created money/credit. These currencies float against the terrestrial currency.\n5. Because the rights to production of waste heat on earth cannot increase, those trying to save money in terrestrial heat-currency may be subject to a negative interest rate or inflation in the terrestrial currency if he actual quantity of waste heat that can be safely disposed of by the planet declines due to government decree. When the global heat production limit is increased the terrestrial currency appreciates versus the off world ones, and vice versa when the terrestrial limit decreases.\n6. The 10% remaining on earth must spend their terrestrial currency on power production to maintain their standard of living, but also on importing finished goods from off world manufacturies (the data centres may also be off world). The off-worlders selling goods to earth get in return terrestrial currency that they can only redeem by either coming to earth an living for a while (many off world workers probably don't live off world all the time), and by importing stuff which cannot easily be manufactured in space - mainly stuff like quality food and drink, works of art, things like that. Ultimately to work, there has to be an equilibrium in which neither the off world nor terrestrial economies run a persistent trade surplus.", "130" ], [ "People traded internationally before the invention of currency\nThe pop idea of barter prior to the introduction of currency is an invention, and it has little to do with how people actually traded. The idea that people were limited to on-the-spot exchanges of say two chickens for a sword and a cabbage is completely ahistorical. In fact, people were making complex, and temporarily disjoint trades long before this idea was formalised into currency. Debts were simply recorded and settled in terms of goods rather than abstracted into currency. This trading was smaller scale than it could be with currency but not directly different in kind.\nCurrency was a formalisation of existing practice\nCurrency didn't spring into being out of nothing, it came into being because it formalised trades that were already being made. The first currency was precious metal, traded by weight, which was later stamped into coins of known weight. Ancient Japan used rice as an accounting unit since it was the staple on which other things depended.", "1006" ], [ "Conceptually, goods can be thought of as a form of currency with a complex exchange rate between them, and so the conceptual step from trading in goods to trading in currency is not a big one.\nSo, what does this mean for a world without currency?\nHow could we scale up these pre-Currency practices to a global economy on the modern scale? The answer lies in the concept of debt. A debt is nothing but a promise to deliver, and there's no reason that these can't be traded. Thus, I, a chair-maker take to you, a grocer, a promise to make a chair, I trade this promise for my weekly shop. But the promise is worth more than the weekly shop so you also give me a promise for 8 gallons of beer that the local brewery paid with. I can then \"spend\" that promise elsewhere.\nAt first, this is just barter, but we can scale it up to a global level through the introduction of markets and clearing houses. Just as today stocks are traded on stock markets, I can take the beer promise to the clearing house, and find it's value in anything else by finding what the market will offer and trade it to a promise for whatever thing I want that I can then take to a local provider to get that thing. This requires that providers permit interchange, which will require legal controls, guilds, or other co-operation, but - remember - this is exactly what we're doing right now except that we abstract it into currency so it's operation is not implausible.\nOverheads will be higher, there are more middlemen, and it introduces new complexities but the system should be capable of scaling up to modern industrial scale. The introduction of computing power and mass communication actually makes it much more practical.\nThe difficult question remaining is why on Earth your civilisation didn't make the small leap from here to currency.", "130" ], [ "An Earth-like planet lacking an axial tilt would have incredibly little variation in climate and therefore few global weather patterns. There could still be some forms of air and water circulation because the planet is still spinning, but their movement would not be accompanied by the significant changes in heat and moisture levels that can drive catastrophes like hurricanes. Intense sunlight would also affect all cultures globally, and the concept of a \"year\" would be highly theoretical (those navel-gazers keeping track of the stars) rather than grounded in a seasonal cycle essential to the material wellbeing of all. The length of day and night is absolute in this world. There are no long winter nights, no recurring sense of having more time in the light then less then more again. I think change might be viewed as more linear than cyclical.", "188" ], [ "Perhaps people would tend to be more afraid of change because they are not used to it, or perhaps they would be less afraid of change because they are not conditioned to the highly predictable one of seasons.\nChanges in the magnetosphere when poles shift have huge impacts on geology and evolution. If the axis never \"wobbles\", does it just flip every so often? In a world where all points on the globe receive the full intensity of sunlight, this could have especially deleterious effects. When the poles shift, there is momentary exposure to greater radiation since the planet loses the protective field of the magnetosphere. Our last pole reversal here on Earth was about 800k years ago. In terms of the evolution of hominids, this likely occurred before the first <PERSON> but soon after Homo erectus and Homo ergaster began to harness fire and build simple machines. I don't know of any anthropologist who thinks the pole shift had any role in the development of civilization, but this is fiction so it's fun to imagine. What if that pole shift on Earth contributed to the speciation of Homo sapiens due to mutations from increased radiation? Maybe in this tilt-free Earth you'll find multiple, closely related intelligent species, with biological differences contributing to different cultures in the absence of climactic variation.", "350" ], [ "Social implication of economics based on brain processing power\nI'm working on a future cyberpunk setting in which I would like to explore posthumanism as a main theme. Among some of the ideas I have I want to use the very well explored \"decking\" trope.\nThe idea is that at some point in time humanity managed to create a crude brain-computer interface, that allowed not only access to silicone machines, but also running programs using brain's terrifying processing power. Hence, Technological Singularity followed, with wealth represented by physical production facilities becoming obsolete, as with the excess processing power brute-forcing trade and political forecasts became feasible. Finally, technology demands caught up with the supply and humanity's most relevant stock is now carefully traded processing power. Countless people have been contracted to trade in the power of their brains in exchange for remuneration and it just so happened, that average level of intelligence turned out to be the easiest and most efficient to utilise.\nNow, most people work by plugging in to the data processing cloud for a set amount of time. The contracts vary, with a significant amount of people enjoying games etc. while being plugged in and trading in a set percentage of their brain activity, some having only passive reception of data with minimal amount of interactivity left to the brains posessor. The most extreme (and well paid) employees would lay comatose while nearly 100% of their brains are being devoted to stock trading or running AIs. Of course, majority of the population would unplug for at least a couple hours every day to enjoy real life. That also assumes that entertainment and similar services moved on to the new medium, Neuromancer style.\nThat would leave only the misfits living mostly in the physical world - the geniuses, the morons, the weird and strange minds that are too different to be a mass resource.", "205" ], [ "They would too be able to plug in, but extracting processing power would be too inefficient for them to provide a reliable source of income.\nWhat would be the social and economical implications of such a world? Keeping in mind that <PERSON> literally sells his brain time to someone else and his mediocrity and predictability is prized and promoted, what sort of man would he be? What sort of values would he hold, what would he believe in, what would he want in his life? How would he spend his time off and how would he spend his time? I'm looking for a kind of stereotypical Everyman definition, the same way we recognise the idea of \"mid-range corporate employee\" or \"middle-class big city dweller\".\nIn response to comments: I imagined the transition to processing power as an after effect of general transition towards virtual life. Of course main expenditures would still be rent, utilities, food etc. However, a person might forgo all earthly things and basically occupy a coffin rigged with life support gear, while living his life in virtual environment. Now to create such an immersive environment power of brains of others would need to be utilised, effectively balancing the processing power budget. The excess would be utilised towards human advancement - even if that just means more sophisticated virtual goods (experiences). Generally, it would seem, that at any given point participants in this \"cloud brain\" structure would be divided into suppliers and consumers, with one creating processing power for the others. Apart from human consumption I would imagine there are AIs who require immense number of brains, but enabling technological singularity and - being sentient - having an attitude towards human suppliers. Of course, different variations are possible, such as Matrix scenario where AIs would harvest power by oppression or a more caring one, where proliferation of brains is actually achieved by AIs genuinely forging a better future for humanity.\nI would imagine in a world that derives wealth from processing power, other resources such as food, construction materials and energy would be harvested automatically - using AIs and self-sustaining plants. Work for the incompatible geniuses would be most likely centred on frontier areas - where network is not sufficient to sustain automatic AI or it is not feasible - such as space exploration, colonisation. I would imagine that such a civilisation would be probably halfway to becoming a Type II, according to <PERSON> scale.", "693" ], [ "Religion is, by it's very nature, transcendent. The world and the concerns thereof are not the concerns of religion. Religion answers the quest for the highest good by pointing beyond the world of our physical experience. Therefore members of a religion may very naturally anticipate the end of this life (or the world) with hope.\nThere are interesting theological questions around how the world itself is viewed, and each religion answers such questions differently. For instance, a gnostic Christian might reject the material world as evil, while an orthodox Christian would uphold the inherent goodness of the world which is passing away.", "752" ], [ "It sounds fun to flesh out such details (don't forget to include internal conflicts within the religion itself).\nObviously contemporary American religious thought won't yield much good source material, because modern American religion is almost always hedonism in disguise; but it would be interesting to look into the Tao Te Ching, some writings of the ancient Christian ascetics, and some literature about Hindu gods of destruction for a wide range of perspectives.\nThe basis of a positive arguments used to attract followers would be that the coming world is better than this one. This is an easy argument to make given that in our world: 1) people tend to think the world is bad and 2) they also always seem convinced that it is getting worse, in spite of many efforts to make it better. It therefore shouldn't be hard to draw the conclusion that the world must be remade. Of course, a nihilistic argument could be made that life itself is bad (see any bad guy in any movie ever).\nA pseudo-Buddhist argument might go something like desire causes us to suffer; the pleasure does not outweigh the evil of the suffering; it seems impossible to not desire while in the body; therefore all desire must be extinguished by the apocalypse after which we will …\nI guess, in general, I think it is harder to argue for the goodness of the world than it's badness. Therefore I don't think it should be hard for you to construct convincing arguments for it's demise, be they hopeful for a better existence or not.", "590" ] ]

[ 10537, 38, 7772, 4702, 1875, 650, 8141, 594, 7935, 7015, 9176, 9110, 9191, 5235, 1164, 10081, 5694, 6126, 2023, 3669, 9575, 8304, 6753, 2760, 4530, 1991, 9620, 3838, 9032, 5428, 4516, 3922, 856, 5045, 2167, 708, 4323, 3519, 15, 8556, 5015, 1, 7576, 9317, 6805, 917, 3659, 9253, 1335, 9891, 2869, 6779, 4981, 2643, 8475, 3733, 7858, 1096, 1720, 2349, 2359, 3968, 9923, 7818, 5108, 6120, 6392, 4980, 1753, 4544 ]

[ [ "Transfer of angular momentum during oblique impact with(out) adhesion\nI am solving a problem of 2 identical spherical particles colliding. The impact is oblique. I consider both normal and tangential contact forces. Tangential force is a combination of elastic force and friction.\nI seems reasonable to me that after collision angular momentum should be the same for both particles, i.e. they start spinning in the same direction (particle B acting on particle A creates positive torque, particle A acting on particle B creates opposite force, but the sign of torque is the same). This also agrees with some experimental and theoretical results.\nThe problem starts when adhesion force is added. What happens with the momentum transfer once particles stick together and therefore cannot spin relative to each other?\nIt seems to me that they must start spinning as a whole. However I cannot physically reason it quite well.\nAny suggestions?\nUPDATE: thanks for your replies. This is indeed a complex problem.", "782" ], [ "To clarify some details: I am trying to follow a paper by Thornton & Yin, Powder Technology, 65 (1991), \"Impact of elastic spheres with and without adhesion\". I am timestep integrating all of the forces involved, i.e. collision is not instantaneous (~100-300 timesteps). When the particles stick due to adhesion there is the effect called \"peeling\", and this occurs until critical value of tangential force is reached. Then sliding starts (either a rigid body sliding, i.e. pure friction or micro-slip, which is a combination of elastic force and friction, as by <PERSON> and <PERSON> (1953), ASME J. Appl. Mech,20, p327).\nI have my simulation match the results of <PERSON> and <PERSON> except the case of adhesion. The rebound angles (of particles' centres) match, so the model must be almost working, but the contact patch reflection angle does not (this one depends on spin of the particles caused by collision). This makes me think I am not implementing the transfer of angular momentum right in the case of sticking particles.\nI will try to work out how to modify the angular momentum of the adhered pair from you replies and the paper you attached.", "1002" ], [ "How exactly is kinetic energy transferred between two moving objects when a force is applied?\nI have a question about how kinetic energy is transferred between two objects when a force is applied between them. It sounds simple but when thinking about \"what really happens\" I have some questions. I also checked other entries but couldn't find a detailed explanation.\nI will use a basic example, the elastic collision.\nLet's say I have two objects with the same mass, a spring (considered with no mass) is attached to the first object.\nt=1: Object 1 accelerated from 0m/s to 10m/s. Object 2 is not moving.\nt=2: Object 1 has reached object 2 and the spring between them is compressed. Object 1 and object 2 are now both moving with 5m/s. 1/4 of the initial kinetic energy is stored in each object, 1/2 in the compression of the spring.\nt=3: While the spring expands to its original state, object 1 is decelerated until it reaches 0m/s, object 2 is accelerated until it reaches 10m/s.\nFor the numbers, momentum and energy conservation everything is fine.", "512" ], [ "Momentum and energy has not changed. At t=2 a part of the energy is stored in the compressed spring.\nWhere I have some questions: From t=2, the spring decelerates object 1. The kinetic energy from object 1 is transferred to object 2.\nWhat is the mechanism how the energy \"flows\" through the spring from object 1 to object 2? I have trouble seeing how the object that is pushed back can propagate its energy.\nI can imagine that if I would stop object 2 for a short time, the spring will be compressed further by object 1 (kinetic energy is converted). If I then stop object 1 for a short time the spring will expand and thus accelerate object 2.\nBut as the transition happens continuously, I wonder how this mechanism works in detail. As long as object 1 is faster than object 2 it is clear to me, as object 1 is still compressing the spring. I have trouble to imagine what happens exactly when object 1 is slower than object 2 but it still passes on the momentum and energy.\nIs there any model what happens in detail? Some backgrounds would be highly appreciated. It's one of the questions where I can observe and calculate the behaviour, but would like to have more explanation.", "927" ], [ "Conservation of angular momentum in helicopter\nI have a small RC-controlled toy helicopter with removable tail rotor.\nSuppose I remove the tail rotor, hold the tail with my hand, start the rotor until it moves with constant angular velocity and then let it go. Suppose that the heli remains on the floor all the time.\nThen the body of the helicopter begins to turn into the opposite direction of the rotor.\nMy problem is to explain this in terms of angular momentum. At first this seemed to contradict angular momentum conservation because I assumed that the helicopter is a closed system and there is no external torque, but the rotor keeps the same angular velocity while the body starts to turn into the other direction.\nMy second thought was that I have to take the air into account. If I do that it seems plausible to me to explain it as follows:\nThe rotor transfers angular momentum from to the surrounding air. However to keep it running at constant angular velocity, the motor has to transfer angular momentum to the rotor, which is only possible if the body of the helicopter gets the same amount of angular momentum as goes to the rotor, but into the opposite direction.\nBut then I thought, the body should turn faster and faster to infinity which obviously doesn't happen.", "782" ], [ "So I guessed I should also take the friction with the floor into account where the angular momentum of the body is transferred to.\nThis leads me to the following three questions:\n1. Is my reasoning described above correct or I am completely wrong?\n2. If I would do the experiment on an almost frictionless turntable (which I don't have available at the moment), would the body of the helicopter indeed become faster and faster almost to infinity?\n3. If I would do the same thing in a vacuum, what would happen? I guess (see my first thought above), that the body wouldn't turn at all. Is that correct?\nSo it would be great if someone could clarify this in terms of angular momentum.\nSince the same problem should occur in real helicopters, I guess that there should be some detailed literature about it's physics, but I didn't find any resources about this. So if you have any references for more details or further reading on this problem, it would be also great if you could post it.", "621" ], [ "Effect of internal forces on kinetic energy\nFor a two-body system in absence of external forces, the kinetic energy as measured from ground frame is $K_0$ and from center of mass frame is $K_{cm}$. Find the correct statements:\n$1.$ The kinetic energy as measured from center of mass frame is least.\n$2.$ Only the portion of energy $K_{cm}$ can be transformed from one form to another due to internal changes in the system.\n$3.$ The system always retains at least $K_0-K_{cm}$ amount of kinetic energy as measured from ground frame irrespective of any kind of internal changes in the system.\n$4.$ The system always retains at least $K_{cm}$ amount of kinetic energy as measured from ground frame irrespective of any kind of internal changes in the system.\nI'm confused that internal forces changes kinetic energy with respect to center of mass frame or ground frame? I found a similar question here. But it didn't address my concern.\nMy attempt:\nSay we have a system of particles with masses $m_i$ and velocities $\\vec v_i$.", "512" ], [ "The total kinetic energy is then given by,\n$$E=\\frac{1}{2}\\sum m_iv_i^2$$\nLet’s define a couple useful quantities: total mass, $M\\equiv\\sum m_i$, velocity of the center of mass, $\\vec V\\equiv\\frac{1}{M}\\sum m_i\\vec v_i$. Notation for the particle velocities in the center of mass frame: $\\vec u_i=\\vec v_i-\\vec V$\nUsing these, we can rewrite the kinetic energy as $\\begin{align} E&=\\frac{1}{2}\\sum m_i(\\vec V+\\vec u_i)^2\\ &=\\frac{1}{2}\\sum m_i(V^2+u_1^2+2\\vec V.\\vec u_i)\\ &=\\frac{1}{2}MV^2+\\frac{1}{2}\\sum m_iu_i^2+\\vec V.\\sum m_i.\\vec u_i \\end{align}$\nI know that the first term is the kinetic energy from the motion of the center of mass, the second term is the kinetic energy from the motion relative to the center of mass and the third term is linear momentum of system w.r.t. the center of mass.\nMy question : How will the third term affect the energy of the system if it is acted by an internal force?", "512" ], [ "What frame of refernce to select in statistical mechanics?\nSuppose we have a solid particle suspended inside a fluid such as an ideal gas, as shown in the following picture:\nOur system is the solid particle and the environment is the gas (which acts as a heat bath). Our frame of reference is attached on the edge of the container (shown with black color, ignore the other origin for the moment).\nThe energy of the solid particle, composed of $N$ atoms, in this frame of reference is (for sake of simplicity we assume we have a monoatomic solid and neglect the potential energy terms):\n$$ E = \\sum_{i=1}^N \\frac{1}{2}mV_{i}^2 = \\underbrace{\\frac{1}{2}MV_{\\mathrm{cm}}^2}{\\text{KE of the center of mass}} + \\underbrace{\\sum{i=1}^N \\frac{1}{2}mu_{i}^2}_{\\text{KE with respect to center of mass}} $$\nSelecting a frame of reference\nWhat is the correct frame of reference to apply statistical mechanics? The center of mass of the system or the one attached on the edge of the container?\nIf it is the second, then that means that even macroscopic objects such as a rock emerged on a fluid (e.g. sea), they have on average $\\frac{3}{2}k_\\mathrm{B}T$ energy associated with their center of mass, which means that they move a little bit (because of the very high mass). Is that correct?\nI am giving below a gif from Wikipedia which can help visualizing the process.", "453" ], [ "In this gif the yellow \"ball\" is a dust particle.\nFrame of reference and net velocity\nSuppose now that we describe our system based on the origin with blue color, which happens to move relatively to the container (and also to the gas). This means that now $\\langle V_\\mathrm{cm} \\rangle \\neq 0$. This is not a proper frame of reference to apply statistical mechanics since if the relative velocity is increased, the temperature of the solid particle will increase which doesn't make sense. Is that also correct?\nIn summary, when we want to describe our system in statistical mechanics, what frame of reference should we use?", "453" ], [ "Infinite gravitational potential question\nFor this question I use Newtonian gravity only. Relativistic gravitational/kinematic effects are ignored.\nIt is known that the gravity surrounding a point particle of mass $M$ can be described by gravitational potential $\\Phi$ where $$\\Phi=-\\frac{GM}{r}$$ $r$ is simply the distance from the particle. The gravitational acceleration $\\mathbf{a}$ of a test particle (negligible mass) is defined as $$\\mathbf{a}=-\\nabla\\Phi$$ Because Newtonian gravity is linear in potential, the potential of any arbitrary distribution of multiple point masses is the sum of the potential of all the masses.\nI came across a question that I can't seem to answer it myself when trying to analyze two-body problem using the concept of gravitational potential. Assume that there are two point particles $A$ and $B$ with mass $M$ at points $(-a,0,0)$ and $(a,0,0)$ in Cartesian coordinates, initially at rest relative to each other. $\\Phi$ in this case is time dependent because both particles will move towards each other due to mutual gravitational interaction.", "483" ], [ "However let consider initial situation where $\\Phi$ is $$\\Phi=-\\frac{GM}{\\sqrt{(x+a)^2+y^2+z^2}}-\\frac{GM}{\\sqrt{(x-a)^2+y^2+z^2}}$$ and the acceleration at a point is $-\\nabla\\Phi$, as expected. Acceleration becomes ill-defined at points $(-a,0,0)$ and $(a,0,0)$ because it contains the term $0/0$. I think this is not a problem if you interpret this as the acceleration of a test particle, because it is infinitely close to either $A$ or $B$ and therefore experiences infinite acceleration. But, if I need to calculate the acceleration of $A$ itself, obviously the wrong answer is obtained because you can calculate the acceleration using inverse square law and it is finite. One way around this problem is to consider only the potential due to $B$ $$\\Phi=-\\frac{GM}{\\sqrt{(x-a)^2+y^2+z^2}}$$ This gives answer in agreement with inverse-square law. But it raises the conceptual question: Why can we ignore the self-potential of the particle being accelerated? (This is not an issue for massless test particle)\nAlso, how does this work in nonlinear system, such as general relativity where gravitational field also gravitates and produces even more gravity? I don't think you can just ignore the potential because of self-coupling of gravity.", "766" ], [ "Force needed to pull an end of a bended carpet lying on a floor with constant speed\nConsider this system. A long, thin, pliable carpet is laid on a floor. One end of the carpet is bent back and then pulled backwards with constant speed $v$, just above the part of the carpet which is still at rest on the floor. What is the minimum force needed to pull the moving part if the carpet has mass $m$ per unit length?\nQ: 3 different approaches lead to 2 different values for the minimal force: $\\frac{mv^2}{4}$ and $\\frac{mv^2}{2}$. Which ones are correct? How does energy and momentum conservation happen in this specific system?\nI believe correct answer to this question might be useful for general audiences and for pedagogical reasons, because it addresses a certain mistake that people often do in similar problems.\nMy effort at answering the question. I get the answer $\\color{blue}{F_{\\text{min}}=\\frac{mv^2}{4}}$. Below I give detailed analysis why this is so. My solution is in agreement with conservation of energy and I explain why energy is conserved. Also an explanation from purely dynamical considerations is given by calculating the tension of the carpet at the bending region.\nFirst attempt. Let's consider how new elements of the carpet are brought into motion.\nThis increase doesn't happen abruptly by a jerk, so energy is not dissipated. To see this consider a wheel moving on a flat surface without slippage with constant speed $v/2$. If we go in the clockwise direction from the lowest point of the wheel, then the velocity of the points on the circumference gradually increase from $0$ to $v$ at the highest point, then gradually decrease to $0$ at the second half. This is well known, no jerking motion happens.\nSimilarly to the fact that energy is conserved for a wheel rolling without slippage the energy is conserved in the case of the carpet too: the work done by the pulling force $F\\cdot 2L$ is converted into kinetic energy of the carpet $mLv^2/2$: $F\\cdot 2L=mLv^2/2$, thus $F_{\\text{min}}=mv^2/4$.\nSecond attempt.", "453" ], [ "One might object that the bending of the carpet is not circular. In fact in the above reasoning this doesn't matter. But let's show this doesn't matter in another context too by calculating the tension of the carpet at the bending region.\nWe assume the bending curve has the same constant form at all times. When viewed in the reference frame moving with speed $v/2$ in the direction of the the external force $F$ this bending curve seems stationary. In this reference frame carpet 'flows' along this curve with constant speed $v/2$.\nNow consider a certain element of this curve. Let $R$ be the curvature radius, $\\phi\\ll 1$ - the angle that this element is seen from the center of curvature. The length of the element and its mass is $mR\\phi$. The tension if the carpet $T$ gives this element the centrifugal acceleration $\\frac{v^2}{4R}$:\n$$ T\\cdot \\phi=mR\\phi\\cdot \\frac{v^2}{4R} $$\nThus $T=\\frac{mv^2}{4}$ independent of the curvature.\nNow we get the required minimal force that is needed to pull the end of the carpet with constant speed $v$: $F_{\\text{min}}=T=mv^2/4$.\nIs this analysis in agreement with conservation of momentum? There are two forces that act on the carpet as a whole in the horisontal direction: the pulling force $F$ and the friction force of the floor $F_{fr}$. If the carpet is not sliding along the floor then $F_{fr}=T=mv^2/4$. $F_{fr}$ acts in the same direction as the pulling force $F$. These two forces combined give the carpet the momentum $mLv$: $$(F+F_{fr})\\cdot \\frac{2L}{v}=(mv^2/4+mv^2/4)\\cdot 2L/v=mLv$$ as required.\nThird attempt. This is taken from the book https://www.amazon.com/200-Puzzling-Physics-Problems-Solutions-ebook/dp/B00E3UR79U . They get different answer from the two approaches above: $\\color{red}{F_{\\text{min}}=\\frac{mv^2}{2}}$.", "1002" ], [ "A conceptual propulsion device based on instantaneous energy transfer of relativistic mass\nSetup\nConsider two objects $O_1$ and $O_2$ of mass $m$ each. The objects are connected one to another with a rod of say length $2\\cdot l$. At the middle of the rod, $M$, there is a rotational joint allowing the objects to rotate in a plane. The joint sits on a cart $C_1$ with the center of mass also at the point $M$.\nSuppose the cart in the image above is restricted to move only up and down (that is on $y$ axis) and not allowed to rotate. Also suppose there are no other forces acting on the system but a torque applied to the bar, in the rotation joint such that the bar (along with the objects $O_1$ and $O_2$) are rotating with a constant angular velocity $\\omega$ about the $z$ axis (coming out of screen).\nQuestion\nSuppose that the object which happens to be in the upper half of the cart (that is having the angle with $x$ axis between $0$ and $\\pi$ ) has an extra energy $E_x$ which when it approaches angle $\\pi$ will be \"instantaneously\" transferred to the other object (which now enters the upper half). In simple words we are trying to make always the object in the upper plane have $E_x$ extra energy. Is the cart feeling a small positive acceleration on $y$ axis?\nAnswer (...)\nI think the answer is yes if $E_x > 0$. For each of the objects during rotation the center of mass feels a centrifugal force $F = m\\cdot l \\cdot \\omega^2$ in the direction of the object.", "782" ], [ "However, because the cart is restricted to move only on $y$ axis the acceleration is given by the projection of this force on $y$ axis. Suppose $O_1$ is now on the upper half plane and let $\\phi_1$ be the angle it forms with the $x$ axis. That means it has an extra energy, hence its inertial mass is $m_1 = m + \\frac{E_x}{c^2}$. Therefore the force due to $O_1$ is $$ F_1 = \\left( m + \\frac{E_x}{c^2}\\right)\\cdot l\\cdot \\omega^2 \\cdot \\sin(\\phi_1)$$ while the force due to $O_2$ (which is symmetric to $O_1$ about M) is $$ F_2 = - m\\cdot l\\cdot \\omega^2 \\cdot \\sin(\\phi_1) $$ Hence the total force felt by the cart is: $$F = F_1 + F_2 = \\frac{E_x}{c^2} \\cdot l\\cdot \\omega^2 \\cdot \\sin(\\phi_1) > 0$$ for all $\\phi_1 \\in (0,\\pi)$ Is this true?\nPS: The linear momentum of the cart varies but no external force was applied to the center of mass ... ?! Therefore something might be wrong in my thinking, but I do not know what.\nEdit\nI want to add few words about that \"instantaneous\" energy transfer. Probably there are more methods (or none) but I was primarily thinking about energy transfer through radiation. In the simplest form say the object exiting the upper half of the plane is losing energy (it had some energy say stored in a capacitor) by illuminating the second object. The second object (which now enters the upper half plane) captures this some of this energy becoming therefore \"heavier\" ...", "1002" ] ]

[ 6766, 5702, 9786, 4952, 6735, 214, 5596, 5349, 5396, 11424, 6237, 1690, 7964, 7635, 2620, 785, 9390, 4520, 6961, 4456, 8623, 1323, 7769, 10315, 10904, 4472, 4134, 7397, 4095, 719, 2233, 3070, 8160, 8358, 9388, 6907, 1786, 9771, 8626, 1912, 4763, 10004, 7238, 4831, 2628, 2753, 11356, 6274, 1278, 5784, 6407, 6401, 1074, 5553, 11090, 3136, 132, 2907, 10490, 6096, 4062, 1006, 7546, 8872, 11357, 171, 185, 4375, 4449, 3387 ]

[ [ "Samsung Galaxy S23 Ultra mobile phone, Saudi Arabia version, 256 GB, 5G, dual SIM, black color, 5000 mAh, 4 cameras, 4 GB Ram, 125 GB storage\n5G mobile phone with android system, supports 2 sim cards, equipped with high sensitivity stylus, Snapdragon 8 Gen 2 with 8 cores using 4nm technology, Adreno 740 graphics processor suitable for running most video games, 5000 mAh battery that supports 45W fast charging, 60 percent in 30 minutes, and 15 watt wireless charging, with a 6.8 inch screen size (dynamic amoied), shatter resistant supports facial recognition technology, on-screen fingerprint, compatible with all networks around the world, 4 cameras, 200 megapixel rear camera, 12 megapixel wide front camera, comes with a fast charger, headphones, user manual, extra battery, warrant card, plastic cover, car charger package", "14" ], [ "Smart watch model X9 plus Ultra 2 from Samsung, android system, elegant shape with a strong rubber body to provide more protection, fitness tracker, screen size 1.8 inches\nModern appearance, lightweight, equipped with an amoled touch screen with a resolution of 410 X 502, with a built in lithium battery with a capacity of 420 mAh that lasts up to 3 days of continuous use, wireless charging feature, a strong structure that is resistant to shocks, breakage and moisture, with the ability to voice control, it has easy to use functional buttons, contains a fitness tracker with unique features, and an 8 megapixel camera, compatible with all operating systems, supports a memory card up to 125 GB SD type", "14" ], [ "Bluetooth headset from Infinix, XE22 headset with ultra sound, pure sound, high quality, extra battery, 40 hours of work time\nDesign that ensures comfort with soft cushions during use, designed for travel, lightweight and very comfortable, allowing it to be used for long periods, high fidelity sound and 40 hours playback time thanks to the additional battery, external noise isolation feature in order to provide an enjoyable experience and sound isolated from noise in the place where you you are in, it prevents distraction or interference while listening to music, compatible with all devices and can be connected to all smartphones, tablets and many other devices via Bluetooth 5.3, break resistant plastic body, easy to use functional buttons, supports fast charging.", "14" ], [ "PlayStation 5 device from sony, 3.5 Ghz Zen2 processor 36 CUs, TFLOPs graphics processor, with 16 GB ram, and 1 TB storage\nIdeal for kids and adults, it provides an exceptional gaming experience, 4K, and advanced high performance Zen2 Octa-core processor with a speed of 3.5 GHz, 16 GB GDDR 6/256 bit random access memory (RAM), and an internal storage capacity of 1 TB SSD, supports running games at a frame rate of 144 Hz to provide the best gaming experience to the players, has a modern and elegant appearance, scratch resistant body, (104X390X260 mm), comes with a high quality headphone, a USB connection cable, a customizable plastic cover, a high performance cooling base to maintain a low temperature, 2 comfortable customizable controllers, user manual, and HDMI cable", "14" ], [ "DJI Mini 4 pro fly more combo plus, 45 runtime, 1000m high, 1500 distance, low noise, fold able, extra battery, HD camera\nwith a light weight of 250 grams, a shock resistant body and a lithium battery with a capacity of 1250 mAh this drone allows you to enjoy 45 minutes of flight, with an additional battery, 4 high performance silent motors, with low power consumption, equipped with a 51 megapixel camera that can be upgraded, remote control with a 6.1 inch screen size, control distance up to 1500 meters (in open spaces), obstacle sensing feature, automatic return path determination feature, automatic landing, 6 different flight modes, location finder, available in 3 colors, comes with a charger, extra battery, user manual, DO NOT use at home, NOT suitable for those under 13 years old", "14" ], [ "GardenJoy 21V Electric drill, equipped with 2 speeds, extra battery, lightweight and powerful, 22 bits for various types of metals and walls, 30 minutes on single charge\nWith this model you don't need to worry about rapid discharge. It is equipped with an additional battery and a GTX690-M super motor that consume the least possible amount of energy that can generate 120 N.M of torque.", "14" ], [ "Equipped with an LED light for working in the dark, safe, least amount of noise, suitable for drilling metals/walls/wood. Easy to use, 1.6 KG. Comes with 22 drill bits, charger, extra battery; capacity 2000 mAh, extension leads, screwdriver extension, protective glasses; made of carbon fibre.", "14" ], [ "BONAOK Wireless Microphone, battery operated, Clear Voice Recording, customizable, with direct voice control and adjustment buttons, great gift for adults and kids\nWith a light weight and attractive design, it supports all audio file formats, and provide the ability to record audio with an accuracy of up to 20 micro pascals, with a connection distance of up to 30 meters. Black, customizable and control buttons compatible with most audio devices; no need to setup. Equipped with a battery with a capacity of 1000 mAh provides a recording time of up to 4 hours; it can be replaced when needed. Support SD memory card (up to 64 GB), easy to use, comes with a charger, cleaning pieces, filters.", "14" ], [ "Keurig E-Express Single Serve K-Cup Coffee maker, with a screen, customizable tank and quick replacement, modern and attractive design\nEnjoy the taste of coffee daily at your favorite times with a touch of a button with Keurig coffee maker, customizable, easy to use, with a capacity of 355 ml. Designed to give a modern look to your kitchen, available in several colors; Black-Red-Gray.", "14" ], [ "Equipped with a control screen with a great features, silent, economical, easy to clean. Dimensions (18.5 x 38 x 37 CM), comes with filters, instruction manual, 4 cups, dedicated cleaning tools, mounting stickers, attractive cover. Be sure to use it ONLY on flat surfaces.", "14" ] ]

[ 2383, 7844, 1530, 277, 5494, 4463, 30, 3296, 9922, 7068, 5232, 3950, 3944, 3207, 10618, 9291, 2335, 7104, 3997, 559, 3002, 3619, 10075, 9391, 5814, 1417, 9265, 2778, 10436, 7116, 6089, 5625, 8670, 6745, 10099, 346, 7756, 8787, 2202, 9953, 6109, 6382, 3907, 2405, 7687, 6798, 5944, 9358, 7209, 3671, 3443, 6761, 2193, 2621, 9576, 7416, 2265, 798, 4746, 6839, 6756, 904, 6421, 7362, 3390, 3432, 7237, 11082, 8278, 6390 ]

[ [ "<PERSON>?\naka 'What Happened To This City?'\nTelugu buddy movie. Said buddies are a wannabe filmmaking quartet forever unable to live their dream of making a short movie in Goa.", "666" ], [ "All manner of obstacles blight their attempts be it love or their respective careers but it's mostly their drinking.\nA likeable group when they're not bickering, which to be fair is often. But the charm is mostly present throughout. A few laughs here and there, plus some standard elements (a missing ring!) but the best thing is the absolute bangers in the soundtrack.", "962" ], [ "One Day We'll Talk About Today\nOne day we’ll nitpick about this film.\nAnd that day is today. So here’s a few:\n-You know you’re in for some dysfunctional family tale when the parents gave their kids some pretentious thematic names.\n-And they all starts with A? Really? Don’t they know the struggles of students having a name that starts with A in every hapalan agama in school? Of course they don’t.", "471" ], [ "As long as they’re having a thematic and cool name for their kids.\n-What’s with casting different actor(s) for the same characters who’s in their 30’s and 40’s respectively? I am waiting for some plot points where the young <PERSON> had an accident and had to take a face surgery but it didn’t happened. This is splurging on casts salary right here.\n<PERSON> looks like someone who’s gonna tweet sumtin like “I hate small talks. I wanna talk about atoms, death, aliens, sex, magic, intellect, the meaning of life, faraway galaxies, the lies you’ve told, your flaws, your favorite scents, your childhood, what keeps you up at night, y~\n-Also he be like “Lo BeLom perNah NyoBain GulTik” like a jaksel food snob and yet he took <PERSON> to some random <PERSON> that wasn’t <PERSON>.", "861" ], [ "The Collector\nThe Collector, The Rat Race, and Mouse Mania are three short live action/stop-motion hybrids created for a Disney jubilee SOV release. Not the Disney obsessive myself, I don't know about the other shorts on that tape, but the <PERSON>'s are nothing but brilliant.", "252" ], [ "As usual.\nA single file* with the 3 Jittlov's floats around somewhere. At the end you can see that this was screened as part of an episode of Shields and Yarnell. What happened to television…\n*Probably logging this all wrong because I can imagine that what I watched is similar to the Animato compilation.", "167" ], [ "Batman Returns\nThe Mutual Film Education of José and Camilo #41 (<PERSON>’s Choice)\nIs this… is this the best <PERSON> movie ever?\nI’m sorry, but like? The production design? The costumes? The makeup? <PERSON> <PERSON> <PERSON>. It was drama and panache and fun.", "647" ], [ "Just so much fun and sexiness and contagiously exciting energy that come together kinetically in a way that very few superhero movies have since. Truly spectacular.\nAnd that genuinely sincere and melancholic ending? They would never DARE do that today in a <PERSON> movie.\n<PERSON>! I miss you! Like, the good you. Please come back!", "19" ], [ "The Zone of Interest\n\"Did you set this up to spite me?\"\n<PERSON> illuminated a lot in this Q&A after. He wanted to show the horrors from a specific, strange perspective bathed in the sounds of the surroundings from a detached manufactured reality.", "417" ], [ "Intimate, horrifying, full of situational improvisation, he cut together a 100 minute flick from hours of long takes.\nMy least favorite from his previous films but it definitely sets itself apart. A one time experience, for sure.\nWhen someone asked him to talk about his previous films as part of a retrospective, he said that he prefers to look forward and will not say anything. This goes with the \"visual artist\" angle that he is only an ocassional filmmaker.", "269" ], [ "Mermaids\nI absolutely loved this. A coming-of-age film set in the 60s with <PERSON> playing the unconventional mom who moves after every bad relationship, together her two daughters played by <PERSON> and a cute baby <PERSON> (in her big screen debut).\nPlenty of laughs in the first half of the movie as the family settles into their latest move to Eastport.", "883" ], [ "<PERSON> and <PERSON> did a great job of capturing the dynamics of mother and daughter relationship. And no one plays neurotic characters quite as well as <PERSON>.\nIt’s equally poignant and heartfelt as it was hilarious. The Shoop Shoop song and music video is a such treat", "883" ], [ "Capernaum\nCAPERNAUM really hit it off the park for me. One very angry movie Labaki has made here (and yet, she still found one or two moment of sweet laughter). Political? Maybe.", "170" ], [ "But the reason I love this film so bad is less because of the message and more of how beautifully made the film really is, despite of it's ugly subject matter.\n<PERSON> has already said it -the cinematography by <PERSON> is something to be celebrated.\nThe score, by <PERSON> is phenomenal. I instantly browsed all his previous works and apparently he's a Labaki regular and has always been THIS good.\nEven the sound editing and sound mixing guys did a great job in this: every sound of car engines from streets of Beirut felt like a genuine threat to our protagonists.\nI haven't even mentioned the one that carries the whole film: The actors. <PERSON> did more with his eyes than all the Oscar nominees did with all their might combined. And Boluwatife Treasure Bankole is indeed, a treasure.", "529" ], [ "All About Eve\nThe Criterion Challenge 2021 (#50 A film with spine #1000 or higher)\nProgress: 23/52\nClassic! Deceivingly masterful! A perfect movie! It consists of everything I wished for: a great showcase of the casts, subtle screenwriting, well direction, amazing production design, and whatnot. Plus, it's very engaging. Not a single second felt unnecessary.", "241" ], [ "The B/W bumpy journey was, indeed, quite a captivating ride. Overall, Exploring passion, desire, crave, love, friendship, manipulation, cynicism, the 1950s' \"All About Eve\" is a meticulously crafted, wonderfully depicted classic and a definition of perfection. Highly recommended!", "583" ] ]

[ 11262, 11103, 2394, 5820, 2049, 676, 10612, 10314, 10850, 4089, 394, 4555, 6915, 8175, 2895, 6249, 2454, 4304, 3044, 7247, 3267, 5856, 4114, 3604, 6200, 9646, 10877, 4338, 2063, 8139, 9318, 8615, 8659, 1663, 5409, 11191, 10780, 379, 3735, 4302, 4756, 3911, 9180, 10139, 7400, 8898, 9069, 4218, 8482, 3158, 6298, 5743, 2625, 10319, 7326, 3092, 9313, 9673, 10713, 10623, 1651, 4325, 10008, 2952, 1290, 6829, 727, 952, 10376, 3178 ]

[ [ "damped spring-mass system, wrong position, correct speed and axcelleration\nI am modulating a spring-mass system with gravitation and aero drag, with python programming. The spring is hanging vertically and attached a weight. The user then selects a length to drag it down and the code will generate the graphs\nI solved the differential equation this way.\n\\begin{align} \\sum F_x &= 0\\ \\sum F_y &= -ky + mg - F_\\text{drag}\\ \\mathbf{F} &= m \\mathbf{a}\\ m a_y &= -ky + mg + F_\\text{drag}\\ m\\frac{\\mathrm{d}v}{\\mathrm{d}t} &= -ky + mg - F_\\text{drag}\\ m \\mathrm{d}v &= - ky \\mathrm{d}t + mg \\mathrm{d}t - F_\\text{drag}\\mathrm{d}t\\ m\\Delta v &= -ky\\Delta t + mg\\Delta t - F_\\text{drag}\\Delta t\\ \\Delta t &= 0.001 \\text{ s}\\ \\Delta v &= \\frac{\\sum F_y}{m}\\ v^{i + 1} &= v^{i} + \\Delta v\\ \\Delta s &= v \\Delta t\\ x &= x + \\Delta s \\end{align}\nI solved this in python with this code:\nfrom pylab import *\nfrom matplotlib import pyplot as plt # kilde: https://matplotlib.org/users/pyplot_tutorial.html\n# housekeeping\ng = 9.81 # gravitation\nm = float(input(\"how much do you want the mass to be? \"))\nl = 0.02 # aerodrag constant\nk = float(input(\"insert springconstant:\"))\n#startvalues\nt0 = 0.0 # start time\nv0 = 0.0 # start speed\ndv0 = 0.0#start axcelleration\nxstart = float(input(\"how long do you want do drag it down? \"))\nx0 = (-m*g/k) - xstart # start position\ntime = list() # list for time\ntime.append(t0) # insert start value for time\nspeed= list()\nspeed.append(v0)\nposition = list()\nposition.append(x0 + mg/k)\naksellerasjon = list() # accelleration\naksellerasjon.append(dv0)\ndt= 0.001\nx = x0\nv = v0\nt = t0\n# main algorithm\nwhile t < 20.0:\naerodrag= l*v\nF = (-m*g - k*(x) - aerodrag) #-m*g because gravitation is negative\ndv = F*dt/m\nv+= dv\ndx= v*dt\nx += (dx)\nt += dt\naksellerasjon.append(dv)\ntime.append(t)\nspeed.append(v)\nposition.append(x)\n# Plotting\nplt.figure(figsize=(6,10))\nsubplot(3,1,1)\ntitle(\"Akselerasjon\")\nxlabel(\"tid/s\")\nylabel(\"akselerasjon m/s^2\")\nplot(tid, aksellerasjon, \"b-\")\nsubplot(3, 1, 2)\nplot(tid, fart, \"r-\")\ntitle(\"Hastighet\")\nxlabel(\"tid/s\")\nylabel(\"fart m/s\")\nsubplot(3,1,3)\nplot(tid, posisjon, \"g-\")\ntitle(\"Strekning\")\nxlabel(\"tid/s\")\nylabel(\"posisjon/ m\")\nplt.tight_layout()\nshow()\nI have translated the comments and parts of the code from my language, so sorry for my bad English\nThe speed and acceleration are correct, but the position is wrong. It's too low, although the amplitude of the wave seams correctly.\nI solved the differential equation in GeoGebra and the position should look like this.\nWhat am I doing wrong?\nAfter getting good help in the comments, i added + mg/k in the append\nposisjon.append(x + (m*g)/k)\nThe position now converges to zero, thanks!", "512" ], [ "solve_ivp - Overflow encountered in double_scalars\nI'm modeling an electron that orbits the nucleus. Of course, charged particles radiate away there energy so it'll crash into the nucleus. My approach has been to to evaluate the coulomb force and add the reaction force (given by the <PERSON>-Lorentz formula). The equation of motion would be\n$F = ma = \\frac{1}{r^2} - \\beta\\dot{a}$\nwhere $\\beta = \\frac{2}{3c^3}$ in my units, and m =1. Rearranging this the def eq to solve is\n$F = \\dot{a} = (\\frac{1}{r^2} - a) \\frac{1}{\\beta}$\nand I multiply by $\\frac{x}{r}$ or $\\frac{y}{r}$ to get the x or y directions respectively.", "394" ], [ "The implementation is below\n``` import numpy as np from scipy.integrate import odeint, solve_ivp import matplotlib.pyplot as plt\nc = 137.0 B = ((3.0c*3)/2.0)\ndef func(t, o): # [0x, 1y, 2vx, 3vy, 4ax, 5ay] r = np.hypot(o[0], o1) dodt = [o[2], o[3], o[4], o[5], Bo[0](-(1/r3.0) - o[4]/r), Bo1(-(1/r3.0) - o[5]/r)] return dodt\ninitial = [br, 0.0, 0.0, 1.0, -1.0, 0.0] # [x, y, vx, vy, ax, ay] span = [0.0, 10.0] time = np.linspace(span[0], span1, 10000)\n%% Solve differential equation\nsol = solve_ivp(fun=func, t_span=span, t_eval=time, y0=initial, dense_output=True, max_step=0.05).sol xe, ye, xve, yve, axe, aye = sol(time)\nprint(xe[-1], ye[-1])\n%% Plot states\nplt.plot(xe, ye) plt.plot(xe[-1], ye[-1], 'ro') plt.plot(xe[0], ye[0], 'yo') axx = plt.gca() axx.set_aspect('equal') plt.show() `` I was using odeint before and got the error messageExcess work done on this call` which from this post I know can be solved using a solver that can handle events, however it seems that these events only terminate the solver before it breaks, but I want it to continue as it shouldn't break to begin with if that makes any sense. Using odeint I get the following plot\nAt least it finishes at the origin which it's what it's supposed to do, but it should go around it a few times first. I guess my question is evident, how can I solve the ode without it breaking? Thanks in advanced.\nEdit: I have found the problem (I think). When we get close to the center 1/r^3 becomes too large and breaks everything. However I would like this to go all the way, how do I get around this issue?", "509" ], [ "Determine orbital position after change in velocity\nI am working on a satellite simulator for a project/game and I am stuck on this one bit of physics. So far I have a satellite that revolves around earth on a 2D plane following Keplerian motion using Kepler's equation. Everything is fine and the satellite will orbit many times without problem.", "1023" ], [ "I can also change the velocity of the satellite to manipulate apo/peri points as well as augment of periapsis.\nHowever, the problem occurs if I change the velocity once the satellite passes the PI/2 mark, the entire orbit gets flipped (augment of periapsis is offset by PI) and the true anomaly resets to 0.\nHere is how it is currently implemented: With the assumption that the satellite starts at the periapsis at t0, I find the eccentric and true anomaly given a time since periapsis $w$. Then I find the radius at that angle to get the final position.\n$$t_0 = 0$$ $$E_0 = 0$$ $$M(0) = E_0 - e \\sin E_0$$ $$n = \\sqrt{ \\frac{GM }{ a^3}}$$ $$E = {\\rm kepler}(e, M)$$ $$v = 2 \\tan^{-1}{(\\sqrt{\\frac{(1+e)}{(1-e)}}\\tan\\frac{E}{2})}$$ $$r = a\\frac{1-e^2}{1 + e\\cos{v}}$$\nWhen I update the velocity of the satellite (flight path angle $\\phi$ is recomputed after change in velocity), I recalculate a new true anomaly using $\\phi$, I then find the difference between the old true anomaly and the new true anomaly, and add that to the augment of periapsis $w$. After that I recompute time since periapsis $t$ using the new true anomaly and recompute the orbital parameters as well.\n$$vel = \\sqrt{GM\\frac{2}{r} - \\frac{1}{a}}$$ $$\\phi = \\tan^{-1} ( \\frac{e\\sin{v}}{1 + e \\cos{v}})$$ $$v_2 = \\tan^{-1}{\\frac{r v g m \\cos{\\phi} * \\sin{\\phi}}{r v g m \\cos^2{\\phi} - 1}}$$ $$w \\mathrel{{+}{=}} v_2 - v$$ $$E = \\cos^{-1}{ \\frac{e + \\cos{v}}{1 + e \\cos{v}} }$$ $$M = E - e \\sin{E}$$ $$n = \\sqrt{ \\frac{GM}{a^3} }$$ $$t = \\frac{M}{n}$$ $${\\rm calculateOrbit}()$$\nI noticed if I were to $v = v + \\pi$ if ever $v_2 < 0$ and $v > 0$, then the weird orbit/position flip won't occur until the $v = \\pi$ Otherwise I do not know what the problem is. I would really appreciate it if someone can point me the way, as I have been scratching my head over this for a long time now.", "394" ], [ "Determine path of golf ball\nAll the below is based on the paper the physics of putting from <PERSON>. The goal is to determine the path of a golf ball.\nA golf ball is launched with velocity and a launch angle of towards a hole along the y-axis. The \"green\" is level.\nWe know that the components of are\n$$ v_x = v \\cdot \\sin{(\\beta)}$$\nand\n$$ v_y = v \\cdot \\cos{(\\beta)}$$\nIf $\\beta$ is 0 then $v_x$ is also equal to 0.\nIn this case, the golf ball stops when $v_y$ is 0.", "1002" ], [ "In order to determine when $v_y$ is equal to 0, we need to calculate $a_y$. This is pretty straightforward if we know the coefficient of rolling friction, $\\rho$.\nHowever, I want to determine the path for a \"green\" where slopes are present.The surface of the green is sloped at angles, with respect to the x-axis, $\\theta$ , and $\\phi$ along the y-axis.\nSo, if it is a straight uphill put, $\\theta$ will be equal to 0 and $\\phi$ will be larger than 0.\nAccording to the mentioned paper we have the following formulas for acceleration:\n$$ a_x = -1 \\cdot g \\cdot sin{(\\theta)} - (f \\cdot sin{(\\phi)}) / m$$\nand\n$$ a_y = -1 \\cdot g \\cdot cos{(\\theta)} \\cdot sin{(\\phi)} - (f \\cdot cos{(\\phi)}) / m$$\nIn addition, the direction and magnitude of the tangential component of the contact force are given by:\n$$\\tan(\\alpha) = \\frac{\\rho\\cdot\\cos(\\theta) \\cdot\\cos(\\phi)\\cdot\\sin(\\beta)-I\\cdot\\sin(\\theta)}{\\rho \\cdot\\cos(\\theta) \\cdot\\cos(\\phi) \\cdot\\cos(\\beta)- I\\cdot\\cos(\\theta) \\cdot\\sin(\\phi)} $$\nand\n$$f = \\frac{\\rho\\cdot\\cos(\\theta) \\cdot\\cos(\\phi)\\cdot\\cos(\\beta)-I\\cdot\\cos(\\theta)\\cdot\\sin(\\phi)}{(1 + I)\\cdot\\cos(\\alpha)} \\cdot mg$$\nIt is assumed that\n$$ \\rho = 0.131 $$\nand the moment of intertia of the ball is\n$$ I = 0.40 $$\nAccording to the author\n\"The above expressions for f and φ along with $a_x$ and $a_y$ will allow the x- and y-components of the acceleration of the golf ball to be determined for greens of various slopes. Given these accelerations, along with the initial launch conditions, the paths of the putted golf balls can be determined.\"\nMy question is when does the ball stop? With the level green it is easy; the ball stops when $v_x$ and $v_y$ are both equal to zero. However, if we have straight uphill green where $\\phi$ is large the ball will stop at some point on the hill, where $v_y$ is 0, but the ball will start roll back towards the starting location because of the steepness of the hill.\nWhat is sort of speak the \"end criteria\"?", "1002" ], [ "Is this an acceptable use of $a \\,dx = v \\,dv$?\nFrom the chain rule we have\n$$a\\, dx = \\frac{dv}{dt}\\, dx = \\frac{dv}{dx} \\frac{dx}{dt} \\,dx = v \\frac{dv}{dx} dx = v \\,dv$$\nThis was introduced in an early chapter of my physics textbook and I have been getting a lot of mileage out of it. For example, in part (b) of this problem\nA small object is placed at the top of an incline that is essentially frictionless. The object slides down the incline onto a rough horizontal surface, where it stops in 5.0 s after traveling 60 m.", "563" ], [ "(a) What is the speed of the object at the bottom of the incline and its acceleration along the horizontal surface? (b) What is the height of the incline?\nyou are supposed to use the work-energy theorem, like so:\nLet $x$ denote the hypotenuse of the incline and $\\theta$ its slope. Then $mg \\sin\\theta$ is the component of $F_g$ parallel to the surface.\n$$\\begin{align}W_\\mathrm{net} &= \\Delta K \\ mg \\,x \\sin\\theta& = \\frac{1}{2}m(v_1^2 -0) \\end{align}$$\nGiven $v_1 = 24$ from part (a), we can solve for the height $x \\sin\\theta = 29.36$ m.\nInstead, I noticed that $a\\,dx = v\\,dv$ implies $\\bar a \\Delta x = \\bar v \\Delta v$. The parallel component of the acceleration vector is $g \\sin \\theta$, $\\Delta x = x$, $\\bar v = \\frac{1}{2}(v_1 - 0) = \\frac{v_1}{2}$, and $\\Delta v = v_1$. Then we have\n$$\\begin{align} \\bar a \\Delta x &= \\bar v \\Delta v \\ g \\,x \\sin\\theta & = \\frac{v_1^2}{2} \\end{align}$$\nwhich gets you the same thing.\n* Are there situations in which an approach like this wouldn't work? (I realize that I assumed constant acceleration when calculating $\\bar v$, but anything beyond that?)\n* Is it correct (from a physics standpoint) to say that $a\\,dx = v\\,dv$ implies $\\bar a \\Delta x = \\bar v \\Delta v$? I would prove this mathematically by integrating on both sides, noting that the average value of a function $f(x)$ on an interval $(x_0, x_1)$ is $$\\bar f(x) = \\frac{1}{x_1 - x_0}\\int_{x_0}^{x_1} f(x) dx$$\n* Does my work amount to a derivation of the work-energy theorem, or a lucky circumvention of it?\n* Silly question: If a student did this on a test, would you give them credit?", "1002" ], [ "particles connected with spring, sliding over lines. Question about the potential energy\nI'm currently studying small oscillations with the Lagrangian formalism. I stumbled upon an excercise that I can't seem to understand the method of solving it.\nTwo particles $P_1$ and $P_2$, with the same mass $m$, slide over two smooth, frictionless lines (see the figure). The two lines intersect eachother at an angle of $60$°.", "37" ], [ "The particles experience gravity and are connected by an ideal spring with natural length $l$ and a spring constant $k = \\frac{\\sqrt{3} mg}{l} $.\na) Prove that the equillibrium position of the system is given by $ |OP_1 | = |OP_2| = 2l $\nb) Show that this equillibrium is stable and show that the frequencies of the small oscillations along the equillibrium position are given by $\\omega_1 = \\sqrt{\\frac{k}{2m}}$ and $\\omega_2 = \\sqrt{\\frac{3k}{4m}}$\nTo find the equillibrium position I calculated the potential energy $V$, both gravity and the elastic forces acting on the particle due to the spring contribute to the potential. I started by choosing the movement along both lines as generalised coordinates. $p_1$ and $p_2$ as the movement of particle $P_1$ and $P_2$ respectively.\nThe potential energy due to gravity is given by\n$$ V_g(y_1, y_2) = -mg y_1 - mgy_2 $$ $$ V_g(p_1, p_2) = -mg p_1 \\cos(30°) - mg (p_2 \\cos(30°)) $$ $$ V_g(p_1, p_2) = -\\frac{\\sqrt{3}}{2} mg ( p_1 + p_2 ) $$\nThe potential elastic energy is given by\n$$ V_e(p_1, p_2) = \\frac{1}{2}k (L-l)^2 $$\nWhere I denoted the total length with $L$ and the natural (rest) length as $l$. With the cosine law, the abive can be written as\n$$ L = \\sqrt{p_1^2 + p_2^2 - 2p_1p_2 \\cos(60°)} $$\n$$ L = \\sqrt{p_1^2 + p_2^2 - p_1p_2 } $$\nSuch that the elastic potential energy can be written as:\n$$ V (p_1, p_2) = V_g (p_1, p_2) + V_e (p_1, p_2) $$ $$ V(p_1, p_2) = -\\frac{\\sqrt{3}}{2} mg ( p_1 + p_2 ) + \\frac{\\sqrt{2}}{2l}mg \\left( \\sqrt{p_1^2 + p_2^2 - p_1p_2 } - l \\right)^2 $$\nI then differentiated this potential, but I didn't find the correct answer. Is the potential correct like this? How can you define it in systems like this, where you have to take the natural length in account", "37" ], [ "Integrating twice based on acceleration due to gravity. (Keplar could also be used, but the result is the same). m1 = mass of earth m2 = mass of object, so much smaller than mass of earth it can be ignored\ngravitational constant G = 6.6743 x 10^-11\nm1+m2 = 5.9722 x 10^24\nr is distance between the two objects\nv is combined closure rate of the two objects towards a common center of mass.\na is combined acceleration of the two objects towards a common center of mass\ninitial distance r0 = 76370000\nfinal distance r1 = 6370000\n$$ v = dr/dt \\ a = dv/dt \\ a = (dv / dr) (dr / dt) \\ a = v \\ dv/dr = -G (m1 + m2) / r^2\\ v \\ dv = -G (m1 + m2) dr / r^2 $$ Integrating both sides, with constant v = 0 at r0 $$ 1/2 v^2 = G(m1+m2)/r - G(m1+m2)/r0 \\ v = -\\sqrt{2G(m1+m2)/r - G(m1+m2)/r0} \\ v = \\frac{dr}{dt} = -\\sqrt{\\frac{2 \\ G\\ r0 \\ (m1+m2)-2 \\ G \\ r \\ (m1+m2)}{r \\ r0}} \\ \\frac{- \\sqrt{r0 \\ r} \\ dr} {\\sqrt{2 \\ G \\ r0 (m1 + m2) - 2 \\ G \\ r \\ (m1 + m2)}} = dt \\ {- \\sqrt{ \\frac{r0}{2 \\ G \\ (m1 + m2)}}} \\ \\ \\sqrt{\\frac{r}{r0 - r}} \\ dr = dt \\ $$ Integrate again, using u for substitution. $$ u = \\sqrt{\\frac{r}{r0-r}} \\ u^2 = \\frac{r}{r0-r} \\ r = \\frac{r_0 u^2}{1 + u^2} = \\frac{r_0 + r_0 u^2 - r_0}{1 + u^2} = \\frac{ r_0(1 + u^2) - r_0}{1 + u^2} = r_0 - \\frac{r_0}{1 + u^2} \\ dr = \\frac{2 \\ r0 \\ u \\ du}{(1 + u^2)^2} \\ when \\ r = r0 = 76370000\\ m, u0 = \\infty \\ when \\ r = r1 = 6370000\\ m, u1 = \\sqrt{0.091} \\ t = \\frac{-2 {r0}^{3/2}}{\\sqrt{2 G (m1 + m2)}} \\ \\int_\\infty^\\sqrt{0.091} \\frac{u^{2}}{(1+u^{2})^{2}}du \\ t = \\frac{-2 \\ {r0}^{3/2}}{\\sqrt{2 G (m1 + m2)}} \\left [ \\frac{1}{2} \\left (\\tan^{-1}(u)-\\frac{u}{1+u^{2}} \\right ) \\right ] _\\infty^\\sqrt{0.091} \\ t = \\frac{{-r0}^{3/2}}{\\sqrt{2 G (m1 + m2)}} \\left <PHONE_NUMBER> - \\frac{\\pi}{2} \\right ) \\ t \\approx 32240 \\ seconds $$", "512" ], [ "I am not 100% sure why we go from derivatives involving time to derivatives involving position. I will nevertheless thake the rightmost term in (1.29) and start from there. Let us ignore the constants.\n\\begin{equation} \\int x\\frac{\\partial}{\\partial x}\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big)dx \\end{equation} let us use integration by parts where $x = U$ and $\\frac{\\partial}{\\partial x^\\prime}\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x^\\prime} - \\frac{\\partial\\psi}{\\partial x^\\prime}\\psi^{} \\Big)dx = dV$. Integrtion by parts says that\n$$ \\int U dV = UV\\Big|_{-\\infty}^{\\infty} -\\int V dU $$ where we are integrating over the entire real line.\nNotice that $dU = dx$ and that $V = \\int\\frac{\\partial}{\\partial x^\\prime}\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x^\\prime} - \\frac{\\partial\\psi}{\\partial x^\\prime}\\psi^{} \\Big)dx =\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x^\\prime} - \\frac{\\partial\\psi}{\\partial x^\\prime}\\psi^{} \\Big) $ Ignore the constant of integration.", "955" ], [ "$$\\int x\\frac{\\partial}{\\partial x}\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big)dx = x\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big)\\Big|_{-\\infty}^{\\infty}- \\int VdU = $$\n$$ x\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big)\\Big|{-\\infty}^{\\infty}- \\int VdU = $$ $$ x\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big)\\Big|{-\\infty}^{\\infty}- \\int \\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big) dx $$\nthe sneaky assumption being made is that the wave fucntion $\\psi$, its derivative and ints comple conjugate all go to zero at infinity faster than the linear term $x$ blows up. If you use a gaussian for $\\psi$ you will see that this is so. Therefore the boundary term is just zero, i.e. $$x\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big)\\Big|_{-\\infty}^{\\infty} = 0 $$\nhence $$\\int x\\frac{\\partial}{\\partial x}\\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big)dx = - \\int \\Big( \\psi^{}\\frac{\\partial\\psi}{\\partial x} - \\frac{\\partial\\psi}{\\partial x}\\psi^{} \\Big) dx.$$\nThis should do it. I was not too careful with the integration dummy variables and a few other details but the framework of what you are trying to show is presented here.", "955" ] ]

[ 11385, 1576, 469, 2595, 6995, 5828, 9786, 4049, 9292, 7815, 1223, 10476, 11336, 11142, 8772, 4087, 8419, 4014, 10497, 10337, 4449, 8358, 2006, 8910, 3349, 6736, 1966, 1912, 4006, 3475, 10002, 4376, 4163, 5192, 5553, 10144, 1906, 4625, 3407, 3393, 2433, 785, 10115, 6686, 11264, 3612, 10626, 5631, 1613, 7635, 10892, 3070, 8386, 8964, 403, 5911, 1924, 3135, 19, 47, 3959, 6157, 3818, 8036, 1109, 7055, 8048, 3238, 11356, 9205 ]

[ [ "Question 1\nOkay, so I'll go through my own process for you here step by step, moving down the tree. Here's an annotated version of your diagram with my own thoughts (it's been a while since I've done this but should hopefully be accurate):\nGeneration 2: As you realised, the trait is autosomal recessive so the female (II:2) has the genotype aa. The male is considered wild type unless informed otherwise, giving him a genotype of AA. I think you had worked all this out, but they are shown in red on the diagram.\nGeneration 3: Using the two genotypes of the parents from II (red), we know that all the progeny in generation III are carriers - i.e. Aa genotypes. This is indicated for III:6 in orangey-brown. I think you also worked this out successfully. However in your original chart, III:7 is noted as Aa. III:7 is from outside of the affected family and would therefore again be considered to have be wild type and therefore instead have the genotype AA - shown in purple.\nGeneration 4: In order to work out the potential genotypes of IV:1 we have to do a cross between the two parents III:6 and III:7 - which works out as follows:\n| Male |\n| A a |\n|------------------------|\nF | |\ne A | AA Aa |\nm | |\na | |\nl A | AA Aa |\ne | |\nAs you can see, there is a 50% chance of IV:1 being healthy AA and a 50% chance of being a carrier Aa - shown in green.", "882" ], [ "As IV:2 is affected, we know his genotype is aa (pink).\nGeneration V: Now for answer to your first question. If IV:1 had the AA genotype then the child could never be affected, reducing the odds to 50% immediately. Of this remaining 50%:\n| Male |\n| a a |\n|------------------------|\nF | |\ne A | Aa Aa |\nm | |\na | |\nl a | aa aa |\ne | |\n50% of the offspring would be affected.\nTherefore the probability of V:I being affected is $\\frac{1}{2} \\times \\frac{1}{2} = \\frac{1}{4}$\nQuestion 2\nThe second question seems very odd to me. If IV:2 was unaffected in the literal sense of the word they would be wild-type AA. This would make the probability of them having an affected child as 0.\nAs this isn't one of your options, I assume they mean that IV:2 is a carrier (Aa). We are this time therefore crossing either AA or Aa (IV:1) with Aa (IV:2). Again, if IV:1 is heterozygous dominant (AA) none of her children will be affected. This means the odds are again reduced by a half. In the case that she is heterozygous Aa then the cross becomes:\n| Male |\n| A a |\n|------------------------|\nF | |\ne A | AA Aa |\nm | |\na | |\nl a | Aa aa |\ne | |\nGiving 25% healthy, 50% carrier and 25% affected.\nAs you're looking for affected children: $\\frac{1}{2} \\times \\frac{1}{4} = \\frac{1}{8}$", "882" ], [ "Probability of carrying an autosomal recessive trait given both parents are carriers\nI recently came across a question that asked for the probability of having a child with an autosomal recessive trait, namely cystic fibrosis. From various parts of the question, we can conclude that the father is definitely a heterozygous carrier and that the mother's parents are both heterozygous carriers. In this situation, the only way to produce a child with cystic fibrosis is if both parents are heterozygous carriers, and this will happen with a probability of $\\frac{1}{4}$.\nThe part that causes confusion is figuring out the probability that the mother is a carrier.\nOne student reasoned that a cross between two heterozygous parents will produce a 1:2:1 genotypic ratio, so $\\frac{1}{2}$ of the progeny will be heterozygous carriers. Therefore, the probability that the mother is a carrier is $\\frac{1}{2}$ and the probability of producing a child with cystic fibrosis is $\\frac{1}{2}*\\frac{1}{4}=\\frac{1}{8}$\nAnother student also referenced the 1:2:1 ratio but reasoned that since the mother is phenotypically normal, that the ratio is actually just 1:2 because there is no chance of being homozygous recessive.", "882" ], [ "Therefore, the probability that the mother is a carrier is $\\frac{2}{3}$ and the probability of producing a child with cystic fibrosis is $\\frac{2}{3}*\\frac{1}{4}=\\frac{1}{6}$\nThese two answers are also found at this other question.\nThe last solution proposed is the most interesting. This student referenced the Monty Hall Problem, which is indeed somewhat related to this problem (read more about the Monty Hall Problem). Using the same ratio as above, we can conclude that there is a $\\frac{1}{4}$ chance that the mother carries no alleles for cystic fibrosis and a $\\frac{3}{4}$ chance that she does. The fact that she definitely does not carry two alleles does not change this probability. Therefore, the probability that the mother is a carrier is $\\frac{3}{4}$ and the probability of producing a child with cystic fibrosis is $\\frac{3}{4}*\\frac{1}{4}=\\frac{3}{16}$.\nOut of these proposed solutions, which one is correct? And why are the others incorrect?\nEDIT: To be clear, the solution I initially considered to be correct was the second one.", "882" ], [ "Subtracting shared DNA with half-sibling\nI want to note that I am not a biologist. I've been on a nearly 20-year search for the identity of the parents of my 4th great grandfather (not an easy task.)\nI'm using ancestry.com DNA, GEDmatch, and family trees of my matches in hopes of using DNA triangulation to find my ancestors. In addition, I have a half-sibling who also had his DNA tested which allows me to find common ancestors on this side of the family.\nI read the article \"Relatedness\" on the topic of inherited parental dna with two half-siblings and I'm not sure I understand what the writer means when she says:\nIn other words, you and your half-brother should be able to figure out what part of your DNA came from your mom. And if you subtract out that shared DNA, what is left must have come from your dad!\nMy first thought was that a person and their half-sibling wouldn't inherit exactly the same DNA from their mother, could they? For example, the mother has two different alleles for some trait. Her son could get a copy of one and the daughter could get a copy of the other.", "882" ], [ "Therefore, in the author's example, how could subtracting out the shared DNA with the brother give the girl the ability to identify exactly which DNA must have come from her dad?\nI read on and the author addresses this by saying:\nOne brother inherited the green version of the mother’s chromosome 2, while the other brother inherited the blue version. This means that none of the chromosomes match! So testing wouldn’t tell the brothers which version of chromosome 2 came from which parent.\nIt turns out, though, that it’s really unlikely that siblings would have two totally different versions of a chromosome. This is because of something called recombination.\nShe's talking on entire chromosomes here which is different, but it doesn't seem to address fully why the girl should be able to 100% identify what DNA came from her dad by subtracting the shared DNA with her brother. I read that half-siblings share 25% of the DNA, but the mother here surely contributed more than 25% to each of her children.\nIn practice, my half-sibling shows a genetic relationship to people on our shared parent's side that I do not (and likewise, I have genetic relationships to people on our shared parent's side that he does not.) Therefore, I'm positing that my brother and I each inherited some different DNA from our shared parent.\nI would take the writer's word for it, but I'm confused. Where am I going wrong? (Sorry about the bad biology background.)", "882" ], [ "This is pretty broad question so I'm not really sure what the end goal is here, but here goes.\nThe answer is both: \"yes\" and \"it depends what you mean exactly\". I'll explain what I mean.\nFirstly, you should clarify in your question whether what you actually mean is the substitution rate, or not. The mutation rate, which is how often a given base pair position changes, cannot be observed with any current technique, even Next Generation Sequencing. This is for 2 reasons (that spring to mind, there may be more).\n* If you make an observation at time $t$, and another at time $t +1$, but a base mutates (say A $\\rightarrow$ C) and then mutates back again between your observations, you would not be able to tell that this had ever happened. Thus there would be 2 mutation events which you would not count in your 'rate'.", "882" ], [ "This is one of the reasons molecular clocks based on SNPs tend to underestimate ancestral distances.\n* If a mutation occurs that is deleterious (has a negative effect on the organism), the mutation won't be observed because the lineage of the organism won't survive to be sampled. By the way, the chances of a mutation being deleterious are considerably higher than it being advantageous, but lower than it being neutral.\nThe substitution rate is how many mutations have occurred that persist in the lineage. Now if we assume that when you say mutation rate, you mean substitution rate...\nYes, you can study mutation rate without 'molecular techniques'.\nThroughout the history of classical genetics we've studied mutation rate without access to these tools.\nMy favourite example is basically the one I used in this question, where you can study the emergence of antibiotic resistance in bacteria (since you provided the example of E. coli, this is rather apt).\nIn the papers I linked however, they will almost certainly have used some molecular techniques to validate their answers.\nBut, if we set that aside for the moment, the very first indication of antibiotic resistance one might observe in the lab is seeing colonies of a bacteria growing on a petri dish in the presence of an antibiotic they are supposedly susceptible to.\nNow, if we consider the 'mutation rate' to be the time taken (perhaps counted in the number of generations), for a spontaneous mutation to appear as a phenotype (observed characteristic), you can assess this purely visually without any molecular techniques. If you repeated this experiment however, you would most likely not be able to verify that resistance arose in exactly the same way twice without use of various molecular technqiues.\nAs a molecular biologist though, I would not really consider this a very good approach/definition of mutation rate, which leads me on to...\n'It depends what you mean exactly'\nIf you were to stick to what is probably the stricter but more widely accepted definition of mutation rate (.i.e substitution rate), you'd need molecular techniques to determine this, as you'd need to know precisely which bases are changing.\nHand-wavy list of pros and cons:\nPhenotyping (pros and cons):\n* Quick\n* Cheap\n* Easy\n* Low resolution\n* Possibly not reproducible\nGenotyping (pros and cons):\n* Massive resolution\n* Can be quick in some circumstances\n* Functional information\n* Generally expensive\n* Requires specialist equipment\nNot an exhaustive list by any means.", "225" ], [ "In terms of the biological mechanisms, you have two major mechanisms that come into play:\nThe first is the random segregation of chromosomes during meiosis, the generation of the egg cell. The egg cell will contain only one of each chromosome, and you need it to be the \"maternal\" chromosome each time. This is unlikely (1/2^23 for each generation) but unlikely is not a problem.\nThe second is the crossover mechanism that occurs during meiosis. The parental chromosomes are not directly passed on, they mix with each other and this means you get genetic recombination. So chromosome 1 in an egg cell isn't the same as the maternal chromosome 1 of the individual, or the paternal chromosome 1. It's a shuffled mix of both maternal and paternal chromosomes.\nThe exceptions to this rule are chromosome Y which is passed on directly from father to son and the mitochondrial chromosome which is passed on directly from mother to daughter.\nIt's estimated that crossover occurs around 75 times for human females (55 for human males), but there is nothing biologically that seems force the crossover event, aside from overwhelmingly high random chance. While there doesn't appear to be any mechanism that would check that a crossover has occured in order to determine if the meiosis is allowed to occur, it's extremely likely that it is physically impossible for the chromosomes to all be present during meiosis without enduring crossover events. Not everything is known about how crossover events are regulated but the systems seems to be rigged to always have crossover events occur during meiosis.\nThis makes it a little trickier to argue that it happened despite being unlikely because it might really defy fundamental physical forces.", "29" ], [ "That being said, ignoring the crossover problem and suggesting that it is simply forced random chance seems reasonable enough because there are no known \"checks\" that crossover has in fact occurred that would stop a cell from completing meiosis if it hasn't.\nIf you want a stronger case, I would suggest explaining that the mother passes on 1/2 of her genes and her entire mitochondrial DNA to M2, F1 passes on 1/2 of his genes to M2. Now M2 has half of your genes and half of F1's genes.\nThinking about it a little deeper, I think that the problem you try to solve is not the one you outlined. You're asking if it's possible to \"replace\" your own grandmother, but you frame the problem as needing to provide 100% of your own genes.\nM2 and F2 each pass on half of their genes to you. So you regain 1/4 of your original genes from M2. But you also have 1/2 of F2's genes and 1/4 of F1's genes.\nWhy can't the 1/4 of F1's genes happen to correspond to exactly 1/4 of your genes, and the 1/2 of F2's genes happen to correspond to exactly 1/2 of your genes?\nTo think about it a different way, you already know that your maternal grandparents, together, had 1/2 of your genes. You also know that your father has the other half. By going back in time and becoming your own grandmother you're only changing the maternal 1/4, but you know that this 1/4 already existed.\nThe case in which you need to provide 100% of your own genes is if you go back in time and, instead of replacing your own grandmother by having a child with your grandfather, you try to become your own grandmother by having a child with someone who is not genetically related to you in the original timeline.\nThe interesting thing about your question, though, is that it's only possible if a girl replaces her maternal grandmother. Replacing your paternal grandmother breaks the direct heritage of the mitochondrial genome. Conversely, a boy cannot become his maternal grandfather.", "882" ], [ "In short, being haploid or polyploid should not protect you from Selfish Genetic Elements (SGES).\nAlmost all eukaryotes are polyploid. Plants are the oft-cited example. Wheat, I believe, is hexaploid for example. Polyploid bacteria are the exceptions typically (if we consider ploidy to be of the whole genome). However, even in truly haploid bacteria, the genome in any given cell is usually actively being replicated, so some of the genes are actually present more than once.\nRegardless, replication and repair is an enormously well controlled and regulated process: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1479556/\nSGEs can take many forms depending on your definition and are ubiquitous in nature as far as we can tell.", "667" ], [ "Plasmids which harbour addiction factors, insertion elements, transposons, prophages etc are all technically SGEs. See here for a review: https://www.ncbi.nlm.nih.gov/pubmed/21227262\nI can't find any literature on SGEs in polyploidy directly, but it is well documented that bacteria harbour a considerable amount of selfish DNA - it seems likely that this will be the same if not worse in polyploidy. Plasmid detection is a difficult computational and experimental process (http://bioinformatics.oxfordjournals.org/content/early/2016/11/18/bioinformatics.btw651.full) but one of the hallmarks of plasmid sequences are typically addiction factors (a gene that the host cell must maintain in order to survive - usually an anti-toxin to neutralise a toxin present on a different DNA molecule) as well as phage genes.\nTo address a couple of things specifically:\nAs each copy replicates separately it would seem likely that spontaneous mutations would arise and over time\nThis is somewhat true, there is always minor variation in a population (else evolution wouldnt work!). Sometimes you'll find this is also the case in a single cell - but less often. All cells we have found so far have DNA replication and repair mechanisms - https://en.wikipedia.org/wiki/DNA_repair. The frequency of mutation in the genome is not directly linked to the amount of selfish elements though, making your second point contentious:\nThis seems like an ideal place for selfish copies to arise\nI agree with the premise of polyploidy probably inviting more SGEs (thinking specifically of IS elements and transposons here really), but not because of mutation - rather, just because there are more DNA molecules and sites present for those elements to incorporate into.", "667" ], [ "(Updated question) Problem with Fold-change mean compared to absolute data (in qPCR)\nFor the problem below I am aware of the statistics involved but just can't get my finger around the following:\nIn biology we use qPCR to measure gene expression or basically number of mRNA copies. It does this by counting how many cycles of amplification (2^) it needs to reach a threshold. So to simplify everything lets assume that 1024 copies would require 10 cycles (2^10). If there are more copies it would take less cycles to reach the threshold, therefore 2024 copies would take 9 cycles, 512 copies 11 cycles etc.. Now imagine the following scenario:\nWe have the following samples:\nSample 1. 1024 copies of gene A and 4096 copies of gene B\nSample 2. 1024 copies of gene A and 16384 copies of gene B\nNow we want to compare sample 2 to 1, with gene B in relation to gene A:\nIn absolute numbers this would be:\nSample 1. 4096 / 1024 = 4x more B\nSample <PHONE_NUMBER> = 16x more B\nThe average amount more B = (16 + 4) / 2 = 10x more B\nNow with qPCR the same samples from above would look like the following:\nSample 1. Gene A 10 cycles, Gene B 8 cycles.\nSample 2. Gene A 10 cycles, Gene B 6 cycles.\nNow using the methods standard used for qPCR data we first take the difference between Gene B and A. Followed by the mean of the difference and this is taken 2^.\nSample 1. 10 - 8 = 2 cycles\nSample 2.", "655" ], [ "10 - 6 = 4 cycles\nThe average amount more B = 2^((2 + 4)/2) = 8x more B\nAll publications / software tools etc will compute an average of 8x more B. And I am aware this originated from a log2 scale, however why does this statistically correct method differ in outcome from absolute numbers?\nUpdate I oversimplified my question therefore below some more details of my \"problem\".\nCondition 1 biorep 1. 1024 copies of ref and 1024 copies of gene X\nCondition 1 biorep 2. 1024 copies of ref and 1024 copies of gene X\nCondition 2 biorep 1. 1024 copies of ref and 4096 copies of gene X\nCondition 2 biorep 1. 1024 copies of ref and 16384 copies of gene X\nSo to compute in absolute numbers the average amount more of gene X in condition 2 versus 1:\nWe can forget the reference gene here as cDNA amounts are the same, therefore:\nCondition 1 biorep 1 & 2: average (1024 + 1024) / 2 = 1024 copies\nCondition 2 biorep 1 & 2: average (4096 + 16384) / 2 = 10240 copies\nCondition 2 vs 1: average 10240 / 1024 = 10x more gene X in condition 2 vs 1\nNow with qPCR CT values based on the numbers above:\nCondition 1 biorep 1. Ref_CT 10 and GeneX_CT 10\nCondition 1 biorep 2. Ref_CT 10 and GeneX_CT 10\nCondition 2 biorep 1. Ref_CT 10 and GeneX_CT 8\nCondition 2 biorep 1. Ref_CT 10 and GeneX_CT 6\nNow using the official qPCR calculations:\nCondition 1, Ref_CT mean (10 + 10) / 2 = 10\nCondition 2, Ref_CT mean (10 + 10) / 2 = 10\nCondition 1, GeneX_CT mean (10 + 10) / 2 = 10\nCondition 2, GeneX_CT mean (8 + 6) / 2 = 7\nRef_deltaCT (10 - 10) = 0\nGeneX_deltaCT (10 - 7) = 3\ndelta_deltaCT (3 - 0) = 3\nDifference Condition 2 vs 1 = (2^3) = 8x\nThis equates to 8x more of Gene X on average in condition 2 compare to condition 1. Here now is the difference of 8x vs 10x. Also any program you will use to fill in these CT values it will result in a ratio of 8 compared to 10.\nIs this perhaps as this method equating to 8 should only be used for technical replicates, and bioreps should use a different equation resulting into 10?", "655" ], [ "Monozygotic vs Dizygotic heteropaternal superfecundation\nUpdate: I had a wrong assumption.\n1. After triple checking, I now see that how ordinary monozygotic twins arise is 1 sperm and 1 ovum and then later the zygote splits up.\n2. (1.1. and that that <PERSON> and <PERSON> from rugrats are opposite sex and identical twins is actually an extremely underrated genetic miracle, possibly giving more credibility to the rugrats theory/hypothesis. There's also semi-identical twins in a song of ice and fire - though i guess not game of thrones -, <PERSON>, legend of korra, KND, <PERSON> to test, and i think <PERSON>, etc)\n3. Honest to God, what i weirdly remembered was that ordinary 'monozygotic' twins arise from 2 sperm 1 ovum and then this 'zygote' or whatever of 2 sperm and 1 ovum splits up into 2 zygotes i.e. the splitting up of the 'zygote' is a natural consequence from that 2 sperm have fertilised 1 ovum. From what I weirdly remembered, it would be natural to ask what if the 2 sperm were from different males.\n4.", "29" ], [ "(2.1. Additionally, the <PERSON> and Lil thingy is not really a genetic miracle since all you need is a 22X sperm and a 22Y sperm to fertilise 1 ovum. Damn television. i really thought opposite sex identical twins were not that rare.)\n5. However, apparently it is possible for 2 more sperm to fertilise 1 ovum, in a case called semi-identical twins or something, but there are apparently only 2 reported cases.\nNew question: Okay in the unlikely event that what would be semi-identical twins would arise from sperm from different males, well, then what?\nFrom wikipedia:\nHomopaternal superfecundation refers to the fertilization of two separate ova from the same father, leading to fraternal twins;6 while heteropaternal superfecundation is referred to as a form of atypical twinning where, genetically, the twins are half siblings.\n1. There doesn't seem to be a distinction between heteropaternal superfecundation occurring with two ova and with one ovum. How will monozygotic heteropaternal superfecundation twins look like as opposed to dizygotic heteropaternal superfecundation twins and to identical twins?\n2. Are/Were there real life cases of monozygotic heteropaternal superfecundation?\nThe heteropaternal superfecundation selected cases given on wikipedia seem to be for dizygotic. I tried looking up on google, but I've found so far only dizygotic.", "29" ] ]

[ 185, 7546, 3183, 9541, 5174, 10439, 11159, 3654, 2247, 8573, 1440, 11106, 10959, 11146, 3006, 1671, 6773, 9472, 1948, 1848, 9575, 1114, 2476, 5696, 5288, 7901, 94, 10855, 7231, 5362, 10597, 9245, 8617, 9467, 7348, 10570, 4900, 7902, 5487, 2797, 2763, 10391, 3910, 2546, 2718, 5380, 3165, 286, 10667, 2199, 5398, 2824, 1384, 3311, 5354, 5140, 6860, 3823, 605, 1069, 2762, 9927, 6, 10525, 7038, 10290, 1986, 7110, 10740, 7574 ]

[ [ "Your observation is right.\n1. In females( having XX mammalian germ cells), Oogenesis starts with the process of developing primary oocytes, which occurs via the transformation of oogonia into primary oocytes, a process called oocytogenesis. Oocytogenesis is complete either before or shortly after birth.(1)\n2. The \"germ cells\" are called oogonia. Ovum is not a direct product of meiosis I, the oocyte forms a primary oocyte in meiosis I, which undergoes meiosis II after fertilization to give an ovum.\nThe ootid is the immature ovum formed shortly after fertilization, but before complete maturation into an ovum. Thus, the time spent as an ootid is measured in minutes.", "860" ], [ "....(2)\n(In oogenesis, the ootid doesn't really have any significance in itself, since it is very similar to the ovum. It matures into an ovum.)\nThis diagram sums it up very well:\nOogenesis in Eukaryotic Cells.(A) oogonium where the mitotic division occurs (B) differentiation and meiosis I begins (C) primary oocyte (D) meiosis I is completed and meiosis II begins (E) secondary oocyte (F) first polar body (G) ovulation must occur and the presence of the sperm penetration (fertilization) induces meiosis II to completion (H) ovum (I) second polar body ...(3)\n1. It is commonly believed that, when oocytogenesis is complete, no additional primary oocytes are created, in contrast to the male process of spermatogenesis, where gametocytes are continuously created.\n1. In males, again, as you say, Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. The germ cells here are the spermatogonia. But here, initiation of spermatogenesis occurs at puberty. So, males start producing sperm when they reach puberty, which is usually from 10-16 years old.(4)\n(The process is almost similar to oogenesis, I would recommend you to start with the wikipedia page if you want to understand this in detail.)\nTake away points:\n* The first haploid cell formed from a diploid germ cell is not an ovum/spermatogonia.\n* Ovum is formed after fertilization, whereas sperms are formed at puberty.\n* Oogenesis starts after birth, whereas spermatogenesis starts at puberty.\n1- https://en.wikipedia.org/wiki/Oogenesis\n2- https://en.wikipedia.org/wiki/Immature_ovum#Ootid\n3-https://upload.wikimedia.org/wikipedia/commons/1/1a/Oogenesis.svg\n4- https://en.wikipedia.org/wiki/Spermatogenesis", "860" ], [ "Monozygotic vs Dizygotic heteropaternal superfecundation\nUpdate: I had a wrong assumption.\n1. After triple checking, I now see that how ordinary monozygotic twins arise is 1 sperm and 1 ovum and then later the zygote splits up.\n2. (1.1. and that that <PERSON> and <PERSON> from rugrats are opposite sex and identical twins is actually an extremely underrated genetic miracle, possibly giving more credibility to the rugrats theory/hypothesis. There's also semi-identical twins in a song of ice and fire - though i guess not game of thrones -, <PERSON>, legend of korra, KND, <PERSON> to test, and i think <PERSON>, etc)\n3. Honest to God, what i weirdly remembered was that ordinary 'monozygotic' twins arise from 2 sperm 1 ovum and then this 'zygote' or whatever of 2 sperm and 1 ovum splits up into 2 zygotes i.e. the splitting up of the 'zygote' is a natural consequence from that 2 sperm have fertilised 1 ovum. From what I weirdly remembered, it would be natural to ask what if the 2 sperm were from different males.\n4.", "29" ], [ "(2.1. Additionally, the <PERSON> and Lil thingy is not really a genetic miracle since all you need is a 22X sperm and a 22Y sperm to fertilise 1 ovum. Damn television. i really thought opposite sex identical twins were not that rare.)\n5. However, apparently it is possible for 2 more sperm to fertilise 1 ovum, in a case called semi-identical twins or something, but there are apparently only 2 reported cases.\nNew question: Okay in the unlikely event that what would be semi-identical twins would arise from sperm from different males, well, then what?\nFrom wikipedia:\nHomopaternal superfecundation refers to the fertilization of two separate ova from the same father, leading to fraternal twins;6 while heteropaternal superfecundation is referred to as a form of atypical twinning where, genetically, the twins are half siblings.\n1. There doesn't seem to be a distinction between heteropaternal superfecundation occurring with two ova and with one ovum. How will monozygotic heteropaternal superfecundation twins look like as opposed to dizygotic heteropaternal superfecundation twins and to identical twins?\n2. Are/Were there real life cases of monozygotic heteropaternal superfecundation?\nThe heteropaternal superfecundation selected cases given on wikipedia seem to be for dizygotic. I tried looking up on google, but I've found so far only dizygotic.", "29" ], [ "When you say 'humans can not smell when they have water trapped in their noses', I believe you mean the loss of the sense of scent caused due to nasal congestion, which is due to inflammation, blocking the scent receptors in the nasal cavity (any mechanical blockage preventing odours from reaching the olfactory nerves can cause a loss of sense of smell. This blockage can be due to inflammatory processes like simple infections causing mucus plugs or nasal polyps(1)). Since the basic structure of the respiratory tract is similar in mammals, mucous plugs reduce scent sensitivity in elephants as well.\nOlfaction occurs when odourants bind to specific sites on olfactory receptors located in the nasal cavity. They get into the nasal cavity when you breathe or sniff the air.\nMolecules of odourants passing through the superior nasal concha of the nasal passages dissolve in the mucus that lines the superior portion of the cavity and are detected by olfactory receptors on the dendrites of the olfactory sensory neurons.", "978" ], [ "This mucus acts as a solvent for odour molecules, flows constantly, and is replaced approximately every ten minutes. ...(2)\n(Thanks to @Adhish for the above point.)\nIf the water itself has a scent, then, as @KaPy3141 pointed out, it can be distinguished because it is in contact with the olfactory receptors. Scent of anything else outside cannot be determined, because they do not reach the receptors.\nElephant lungs are attached directly to the diaphragm and chest wall, allowing them to create much greater \"vacuum pressure\" for sucking water through their long trunks, while drinking.(3) To open its mouth to breathe would cause the loss of the low pressure and the water column would expelled. So the water column must first be transferred to the mouth, then swallowed before breathing can recommence.(4) Thus, as far as respiration is concerned, they cannot breathe when the trunk contains a column of water, and, as a result, odourants cannot enter the nasal cavity, and elephants cannot smell in this case.\n1-https://www.ncbi.nlm.nih.gov/books/NBK482152/\n2-https://en.wikipedia.org/wiki/Olfaction\n3-https://www.elephant.se/elephant_lungs.php?open=Elephant%20anatomy\n4-https://www.quora.com/How-do-elephants-breathe-when-drinking-water", "978" ], [ "Actually endosymbiotic theory (we should write \"Endosymbiotic theory of origin of eukaryotic organelles\") suggests a theory about only the eukaryotic organelles (mainly Plastid-family and Mitochondrion).\nI'll divide my answer into 3 parts:\n# Theory of archaeal origin of the eukaryotic host.\n1. How Archaea (Archaebacteria) and Eukaryotes shared a closest common ancestor\n# Endosymbiotic theory of origin of Eukaryotic cell organelle.\n2. How mitochondria originated?\n3.* How plastid was originated?\nPlease keep in mind, in origin and evolution of eukaryotes, origin of the host cell (and the nuclear genome) is a different event; and origin of eukaryotic organelles mitochondria and plastid is another different event.\nTheory of archaeal origin of eukaryotic host\n1. How Archaebacteria (archaea) and precursor of eukaryotes evolved from their nearest common ancestor.\nIt has been established (First by <PERSON>, mainly based on her prolonged researches on rRNA sequences) (PDF) (REFERENCE-1 *) that Eukaryotic \"host cell\" (with the nuclear genome) shares the closest common ancestor with Archaebacteria, not the eubacteria.\nFurther reading: Relationships of Eukaryotes and archaea\nFig-1: Here the horizontal axis is the time axis.\n(The small black balls here indicating many other possible extinct lineages (hypothetical, just todemonstrate how evolution works) )\nOn other hand, After the group bacteria (eubacteria) developed (better to say the precursor of bacteria further diversified, bacterial groups like proteobacteria and cyanobacteria developed. For bacterial phylogeny, see Wikipedia (image)\nEndosymbiotic theory:\nNow endosymbiotic theory tells that the origin of some eukaryotic organelles (at least Mitochondria and Plastid) were different and distant taxa from the eukaryotic cessls, and they came from outside and entered into the cell and formed symbiotic relation; and the endosymbionts gradually lost their free-living ability, were gradually became part of host cell. The peculiarity of this \"Endosymbiosis\" phenomenomenon in evolution is that; not only the \"parent\" taxa; but another \"distant taxa\" merge from side of the lineage. The concept is not only confusing but it was so shocking that when <PERSON> first proposed this hypothesis, the idea was rejected.", "29" ], [ "Later on, genome-based research proven that the origin of mitochondria (and as we will see, plastids); were originated from mutualistic- symbiosis.\n2. How mitochondria evolved in eukaryotes?\nIt has been suggested, the \"precursor\" of eukaryotes (which was descendant of closest-common ancestor with archaebacteria), the host cell, engulfed some aerobic eubacteria (perhaps allied to proteobacteria) those aerobic eubacteria gave rise to mitochondria. These derived protists were unable to photosynthesise. This endosymbiosis is very much similar to previous one.\nFig 2a: origin of the organelle mitochondria.\nSo our evolutionary tree now look like\nFig 2b: Origin of mitochondria in eukaryotes, placed in evolutionary tree.\nThe white balls here represent living and contemporary groups.\n(Just like previous picture the extinct groups are hypothetical and representitive; but the relative positionsof clades for proteobacteria and cyanonbacteria is actual, and taken from from <PERSON>'s microbiology **)\n(A common example of intracellular endosymbiosis will help us to understand the theory- we can still see such intracellular symbiosis in rhizobial bacteria colonising plant root/tissue; where we get both intracellular stage and culturable extracellular phase)\n3. How Plastids evolved then?\nFrom this group of protists, a certain group again engulfed a sort of eubacteria (allied to cyanobacteria). The cyanobacteria gave rise to plastids , and photosynthetic protists.\nThere are disputes about whether plastid and mitochondra evolved simultaneously or at an interval. According to <PERSON> they originated simultaneously, but according to other newer sources like this and this , mitochondria appeared first.\nFig.3.a. one lineage eukaryote that already formed mitochondria, forming another association with a photosynthetic eubacteria.", "3" ], [ "In short, being haploid or polyploid should not protect you from Selfish Genetic Elements (SGES).\nAlmost all eukaryotes are polyploid. Plants are the oft-cited example. Wheat, I believe, is hexaploid for example. Polyploid bacteria are the exceptions typically (if we consider ploidy to be of the whole genome). However, even in truly haploid bacteria, the genome in any given cell is usually actively being replicated, so some of the genes are actually present more than once.\nRegardless, replication and repair is an enormously well controlled and regulated process: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1479556/\nSGEs can take many forms depending on your definition and are ubiquitous in nature as far as we can tell.", "667" ], [ "Plasmids which harbour addiction factors, insertion elements, transposons, prophages etc are all technically SGEs. See here for a review: https://www.ncbi.nlm.nih.gov/pubmed/21227262\nI can't find any literature on SGEs in polyploidy directly, but it is well documented that bacteria harbour a considerable amount of selfish DNA - it seems likely that this will be the same if not worse in polyploidy. Plasmid detection is a difficult computational and experimental process (http://bioinformatics.oxfordjournals.org/content/early/2016/11/18/bioinformatics.btw651.full) but one of the hallmarks of plasmid sequences are typically addiction factors (a gene that the host cell must maintain in order to survive - usually an anti-toxin to neutralise a toxin present on a different DNA molecule) as well as phage genes.\nTo address a couple of things specifically:\nAs each copy replicates separately it would seem likely that spontaneous mutations would arise and over time\nThis is somewhat true, there is always minor variation in a population (else evolution wouldnt work!). Sometimes you'll find this is also the case in a single cell - but less often. All cells we have found so far have DNA replication and repair mechanisms - https://en.wikipedia.org/wiki/DNA_repair. The frequency of mutation in the genome is not directly linked to the amount of selfish elements though, making your second point contentious:\nThis seems like an ideal place for selfish copies to arise\nI agree with the premise of polyploidy probably inviting more SGEs (thinking specifically of IS elements and transposons here really), but not because of mutation - rather, just because there are more DNA molecules and sites present for those elements to incorporate into.", "667" ], [ "So I've dug a bit into how a 'normal morphological' form is defined and characterised, since assessing morphology into 'normal' and 'not normal' is always a very tricky thing.\nLooking into the method section of the source you cited, we get:\nAll laboratories generating the data analysed here used standardized methods for semen analysis [...] The various editions of the manual provided similar methods for assessing sperm concentration, motility and morphology but provided different criteria for categorising morphology.\nSo the problem begins already with the fact that there is not one, but multiple different recommended practices.\n(For anyone interested the different staining methods used were: Bryan–Leishman [B], DiffQuik [D], Haematoxylin and Eosin [H], Papanicolaou [P], Quickdip [Q] and Shorr [S]. Of thses H, S and P were used for generation of the 'normal morphology' reference set).\nClearly this problem was also obvious to the authors, so they tried to restrict the data they used:\nAlthough all centres reported using WHO procedures, the recommended methodologies have changed over time, and many centres have experienced difficulties with the subjective assessments of morphology. Data on normal sperm morphology were only included if results were reported as determined according to the so-called ‘strict’ (<PERSON>) method (WHO, 1992, 1999).\nFortunately these WHO guidelines are available on google books and they require the following points to met (most of which were defined by 95% confidence intervals of control samples):\n* head length 4.0-5.0µm\n* head width 2.5-3.5µm\n* head length-to-width ratio 1.5-1.75\n* well defined microsomal region compromising 40-70% of the head area\n* mid piece should be slender, <1µm\n* [mid piece should be] 1.5x size of the head\n* [mid piece should be] axially attached to the head\n* Cytoplasmic droplets should be less than half size of the head\n* Tail should be [...] approximately 45µm long\nPlus one very important sentence:\nThis classification scheme requires that all 'borderline' forms be considered abnormal\nThis sentence is important, because it means that each criterium stated has to be fulfilled for a single sperm to classified as morphological normal. If we take only the numeric requirements (which should cover ~95% of the normal value distribution for a healthy population) and assume that they are not correlated, this means that for any given single healthy sperm we have a $0.95^9 = 0.63 = 63\\%$ chance that it is within the 95% interval of all defined parameters.\nThis means that applying this strict categorisation scheme should even for a 100% healthy population only result around 63% sperm cells categorised as morphologically normal (ignoring that the parameters are probably not interdependent which would make it a bit better).\nIf we now take into account that the analysed samples were probably not 100% healthy cells and remember that the (reported) difficulties of assessing morphology, I think that the reported values for 'morphological normal' are not as quite as unexpected as they might seem.\nNote: all bold highlighting in the quote blocks was added by me.", "312" ], [ "I think the article that quoted(1) is different to what the link shows now(2). However, both the article quoted and the one in the link are relevant to the question.\nAlzheimer's Disease : In a nutshell, AD is the most common form of dementia. Although the exact cause is still under investigation, several genes have been implicated in the development of AD. One of the things you see in the brain with disease progression is beta amyloid plaque deposition which disrupts brain activity.\nBrain Activity : While the brain consumes around 20% of our body's energy at a baseline, an increase in brain activity only increases this consumption by around 5%. <PERSON>, the first to record an EEG stated that \"mental work, as I explained elsewhere, adds only a small increment to the cortical work which is going on continuously and not only in the waking state\".(2)\nHowever, there are a few 'intrinsic' networks or regions that perform functions such as \"information processing for interpreting, responding to and predicting environmental demands\". One of the areas active in this state of the brain is referred to as the 'default mode network' (DMN). It's thought that DMN is main the target of the amyloid plaques responsible for Alzheimer's Disease.(2)\nHowever, there are other multimodal regions of the brain that perform processing of various types of information. It's now suggested that \"it appears that regions vulnerable to Ab deposition do not simply involve the DMN, but rather comprise multimodal brain regions that are highly interconnected, plastic, and capable of rapid ATP generation\"(1).\nSo it's a variation of activity in these particular areas - not all - that are implicated with Alzheimer's Disease. When you are performing a task, activity in these areas diminish.\nWhy keep the brain intentionally active : The reason for the hypothesis that actively engaging in challenging activity may reduce the risk of AD is that individuals with a high cognitive reserve have been shown to cope with the pathological changes such as beta amyloid deposition better. Cognitive reserve has been linked to a bunch of factors including \"education, occupation, socioeconomic status, social networks and lifelong participation in cognitive and physical activity\" and reflects \"lifelong patterns of behaviors, endogenous factors (including genetics) and exposure to environmental factors\"(1).\nMoreover, it's suggested that perhaps higher cognitive reserve increases neuronal efficiency which has been shown to reduce plaque deposition.(1).\nSo <PERSON>'s question and jp89's answer aren't really contradictory.\n1. <PERSON>, et al. Lifespan brain activity, β-amyloid, and Alzheimer's disease. Trends in Cognitive Sciences.", "882" ], [ "2011. 15(11):520-526.\n2. Raiche. Two views of the brain. Trends in Cognitive Sciences. 2010. 14(4):180-190.\n3. <PERSON>, et al. Imaging the default mode network in aging and dementia. Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 2012. 1822(3):431-441.\n4. Harrison's Principles of Internal Medicine. 16th <PERSON>.", "495" ], [ "There will be few rapidly-dividing cells in a fresh wound (which is the wound to which H2O2 is applied). In general, it is a good idea to avoid applying irritants to rapidly dividing tissue.\nHydrogen peroxide is a weak mutagen. It is produced in many body tissues, ingested in drinks, produced by mouth bacteria, etc. It may well cause some cancers. Some OSHA-mandated literature does warn that it is a mutagen and must be handled with care, but these are warnings to people who work with concentrated solutions.\nHowever, a relatively weak hydrogen peroxide solution, even if it is mutagenic, would need to be left in place and active (or renewed) for a long period of time to produce skin cancer.", "225" ], [ "As it has been a staple of first aid kits for decades, and this association has never been made clinically, my best guess is that the benefit (as a bacterocidal agent) far outweighs the risk in the treatment of minor wounds. As in all things, however, prudence is advised. (I myself don't use it because soap and a lot of water is quite effective. Nor is it used in the care of wounds in Emergency Rooms where it is considered to be detrimental to wound healing. If I were in a country where clean water and soap were in short supply, I might well use it if necessary.)\nBecause it is an irritant (and many irritants can be considered mutagenic), it is actually used to treat precancerous skin lesions, the finding being that it affects the more rapidly dividing pre-cancerous cells than the rest of the epithelium.\nFar more potent peroxides have been used topically, which may increase the risk of skin cancer.\nInterestingly, one of the responses of skin cells to H2O2 is the generation of an oxygenase to fight the effects.\nTopical sulindac combined with hydrogen peroxide in the treatment of actinic keratoses\nEffects of Peroxides on Rodent Skin: Epidermal Hyperplasia and Tumor Promotion\nHeme oxygenase is the major 32-kDa stress protein induced in human skin fibroblasts by UVA radiation, hydrogen peroxide, and sodium arsenite\nRecent Advances in Wound Care, <PERSON>, <PERSON>, MS, and <PERSON>, MD", "938" ] ]

[ 1227, 7134, 8206, 3910, 9882, 2023, 1251, 6969, 7110, 1473, 724, 11106, 11386, 10252, 4459, 1671, 10487, 8573, 1948, 7348, 10545, 11159, 5417, 7102, 8430, 9987, 9033, 8510, 5908, 7902, 4765, 2545, 7308, 11403, 3659, 10830, 6860, 2247, 5398, 3654, 9927, 9623, 1556, 5174, 9132, 4714, 7020, 4278, 11251, 2546, 1962, 10570, 2217, 10912, 1069, 976, 9903, 7810, 10475, 3628, 7224, 938, 5808, 5253, 4681, 147, 2925, 7222, 1956, 8845 ]

[ [ "Kid's Bench & Bookshelf From a Single 2x10x8 Piece of Lumber\nIntroduction: Kid's Bench & Bookshelf From a Single 2x10x8 Piece of Lumber\nThis was a bad idea. I went into this build thinking I was going to knock this out in a couple of days. Unfortunately for me the dimensional lumbar had a different path for me.\nMy first take away from this build is; if you want to build this don't do it using a single 2 x 10 x 8 piece of lumber. While you may save some money, you will waste a lot of time in milling and glue ups to get the actual size of lumber you could have just bought in the first place.\nMy second take away from this build is if you decide to use a single piece of dimensional lumber make sure to take the time to pick the best piece for milling. Not only is it important to look at the face of the wood for excess knots, defects, and straightness it is also important to check the grain pattern on the end grain of the wood. I didn't do this, which resulted in many minor annoyances I had to deal with down the road. When looking at the end grain of the wood try to find a piece that has perpendicular lines that are spaced fairly evenly across going from the top to the bottom and not curved lines that look like the letter 'C'. Those curved grain lines and dampness of the wood will result in some surprisingly cupped and warped pieces of milled wood. It really is amazing how much wood can move in just a few hours.\nMy third take away from this build I mentioned above, 'dampness' of dimensional lumber. I didn't take into account how wet the wood was when I bought it. It was a cold day, so I just assumed the wood was just cold due to the weather but once I made my first cut; I realized that the wood was still damp. Ideally if I were to do this again, which I won't, I would purchase the wood and let it dry out in my garage before starting to mill it. Letting it dry out will help in reducing wood movement and warping later on.\nThink of this Instructable more as a cautionary tale than woodworking plans.", "431" ], [ "I will include my measurements, but these are more fluid and not so much set in stone as I had to adapt my plan to the whim of the wood.\nSupplies\n1pc. - 2 x 10 x 8 Lumber\nTable Saw\nBand Saw\nPlaner\nDrill Press\nBar Clamps\nHand Saw\n<PERSON>\nSander\nSand Paper\n3/8 inch Plug Cutting Bit\nPencil\nMeasuring Tape\nSquare\nWood Glue\nWood Filler\nPaint Primer\nSpray Paint\n#6 1 inch Wood Screws\nDrill\nDrill Driver\nDrill bits Various Sizes\nPPE\nStep 1:\nThe first thing I did was set my table saw fence to 4-1/16 inches wide. I need to rip my 2x10x8 into two 4-1/16 inch wide pieces and one 7/8 inch wide piece. Basically I just made two rip cuts at 4-1/16 inches and the remaining piece was about 7/8 inch wide.\nStep 2:\nNext, I marked a center line using my square along the edge of the two 4-1/16\" pieces and took them to my band saw to rip them in half. Since the boards are 8 feet long it is best to do this with two people to help support the wood. You want to end up with 5 pieces total at this point. The 7/8\" piece does not get ripped in half.\nStep 3:\nAfter ripping on the band saw, all of the 4-1/16' pieces go through the planer. I ended up with pieces that were about 5/8\" thick after all the plaining was said and done. The 7/8\" piece does not get planed.\nStep 4:\nNow we have to cut the pieces that will make up the sides of the bench. Each side will be made up from one piece that is 19-1/2\" long and two 10\" pieces that will all be cut from the 4-1/16\" wide boards.\nStep 5:\nAnd here is where the trouble starts, the cupping begins to rear its ugly head in our direction. But we do not look away! Nay! I say, for we have a table saw!! Since the pieces are cupped, the edges are no longer at a 90-degree angle. They are tilted in ever so slightly which will prevent us from getting a good glue up. To compensate for this, I take all the pieces that make up the sides of the bench and trim them on my table saw.", "76" ], [ "A Plywood Pencil Dispenser - a Tale of Hubris Turned to Humility\nIntroduction: A Plywood Pencil Dispenser - a Tale of Hubris Turned to Humility\nI am not an arrogant person. If anything I continually suffer from imposter syndrome. But, for some reason I went in to this build with unwarranted and unchecked confidence, more on this later.\nLet's start at the beginning, while on Instagram I noticed that @Instructables had posted a Plywood Challenge I thought I might see what I could come up with for the challenge. Unfortunately I didn't have any ideas for a plywood project and I didn't have very much plywood on hand. Inspiration hit while my kids were at school, due to the pandemic they are doing online schooling. So I have a lot more interaction with them during the day related to school and school activities. Recently I noticed that my son kept loosing his pencil, we don't live in a mansion but somehow this kid keeps loosing his pencils. On three separate occasions in the last two weeks he has asked me if I have seen his pencil? I tell him, \"no\" but ask him, \"how is it that you lost your pencil?\" He shrugs his shoulders and asks me if he can have one of mine. I have a small box of pencils I keep in my shop, which he knows about so of course he knows I have ready supply of sharpened pencils available. After the third time he asked me inspiration struck and I decided I would try to make a pencil dispenser out of plywood. I had a few scraps of 1/2 inch plywood and a long narrow cutoff of 3/4 inch plywood. I also had an 8x10 inch piece of plexiglass that I was going to turn in to a palm router base but never got around to making it. I think this is were the hubris started to creep in; I started to feel pretty good about the materials I had on hand I wouldn't have to go to the store to buy anything and we even had two boxes of pencils from our back to school shopping run.", "936" ], [ "Needless to say I was feeling pretty good about this build, these feelings would not last.\nStep 1: Amalgamation of Scraps\nThe first pic shows the random amalgamation of scrap pieces of plywood and other odds and ends that I used for this project. I took a 3/4 inch piece of plywood that was 1-5/8 inches wide and cut a piece that was 8-3/4 inches long on my bandsaw, this would be the bottom of the dispenser. I then cut two 7-3/8 inch long pieces of 1/2 inch plywood that also measured 1-5/8 inches wide. These would be the left and right sides of the dispenser.\nStep 2: Three Become One\nI didn't have a big enough piece for the back panel so I cut a strip of 1/2 inch plywood to glue together two other 1/2 pieces of plywood to make one piece that would be large enough to be the back panel. After gluing and clamping the back panel pieces together it measured 9-1/2 inches wide by 7-3/8 inches tall. Once the glue dried I set it aside for later use in the construction.\nStep 3: Two Sides to Every Story\nI used a 1 inch Forstner bit to make two holes in the two side pieces, these holes would be for the round dowel that would carry and then dispense the pencils. The one inch hole is centered side to side and measures about 1-3/4 inches from the center of the hole to the base of the side piece. You need enough clearance for the pencil to drop out of the bottom of the dispenser.\nThe last pic shows a quick mock up of some of the construction.\nStep 4: Buying Is Easier Than Making\nFor the pencil carrier/dowel I used a couple of pieces of plywood cutoffs from another project How to Make a Wooden Kettlebell that I glued together to make a blank. These were two corner pieces made up of 1/2 plywood. Instead of using cutoffs you could just buy a 1 inch dowel which I would almost guarantee would work way better than what I made.\nStep 5: Square Peg Round Dowel\nOnce the glue dried I chucked the blank in my lathe and turned it to as close I could get to 1 inch round. I'm a beginner on the lathe so I didn't exactly nail the 1 inch diameter but I got close. Then sanded the dowel up to 400 grit. I would later come to realize that I should have made this piece longer. Buying a 1 inch dowel would be easier and more precise.\nStep 6: This Looks Sketchy\nThis is where things stated to take a turn for the worse.", "599" ], [ "How to Build a Kayak Rack\nIntroduction: How to Build a Kayak Rack\nIn this post I'm going to show you how to store your kayak. In the last year my family has decided that kayaking is definitely for us. So much so that my wife and I decided to make the investment in everyone in the family owing our own kayaks, which for us means five kayaks. And while kayaks don’t weigh a lot, they can definitely eat up space quickly.\nMy primary objective with this project was to create a storage rack that allowed me to stack the kayaks up on the garage wall giving me a minimal footprint and to do it in a budget friendly way.\nIf you like this instructable be sure to check out my most popular instructables below:\n5 Pro Tips for Making Cutting Boards\nHow to Make an End Grain Butcher Block\nHow to Make a Slab Flattening Mill\nThe Ultimate Table Saw Fence\nIf you like this instructional content you can also find me at:\nMy Website (full tutorials, plans, videos): https://mwawoodworks.com\nMy YouTube (all my build videos): https://youtube.com/c/mwawoodworks\nMy Instagram (behind the scenes stuff): https://instagram.com/mwawoodworks\nMy Pinterest (things I find inspirational) : https://pinterest.com/mwawoodworks\nSupplies\nMaterials & Supplies* Tools*\n(3) 12' 2x4s Miter Saw\n(4) 10' 2x4s Table Saw & Crosscut Sled (optional plans on my site)\n(2) 10' 4x4s Hammer Drill & Driver Combo\n3\" Construction Screws Hammer Drill (if fastening to concrete block)\n4\" Tapcon Concrete Anchors Masonry bit (if fastening to concrete block)\n(4) Black Utility Mats Staple Gun\nStep 1: Cutting the Parts\nThe design I settled on used three 12’ 2x4s, four 10’ 2x4s and two 10’ 4x4s. That gave me almost the exact amount of material needed and I ended up with almost no waste. Since I want to store five kayaks I needed 20 pieces in total. Of course you can scale up or down depending on how many kayaks you have.", "181" ], [ "You need two support arms per Kayak.\nI chopped all my 2x4s down to length, making 12 of the pieces 36” and 8 of the pieces 32”. The shorter pieces will be used for the smaller kayaks.\nI then needed to make some smaller pieces to use as cross braces and I cut these using my crosscut sled at the table saw. This could have been done at the miter saw too if you don’t have a table saw.\nI find the crosscut sled to be easier and more accurate when making repeat cuts this small. I needed 30 of these little pieces in all.\nStep 2: Assembling the Support Arms\nAnd That’s it for the cutting on this project, all that’s left to do is assemble everything. I need to assemble ten support arms and to do this I placed two boards against one of the 4x4s like this.\nI then put one of the cross brace pieces in the middle and clamped the whole thing to the 4x4.\nUsing 3 inch construction screws I fastened this together.\nI then flipped the whole thing over and repeated this process on the other side.\nFinally, I added one cross brace approximately in the middle. Doesn’t have to be exact, I just eyeballed it.\nThe idea here is the support arm will attach to the 4x4 like this and create a tight fit.\nI’ll be able to fasten the support arms to the 4x4s on each side as well as in the middle using the cross brace.\nI just continued on using this same method until I had 10 total support arms (2 for each kayak).\nStep 3: Preparing the Support Posts\nNow for the 4x4s I marked out screw locations at 2 ft intervals.\nI then marked the center with a center punch.\nI used a ¾” forstner bit to countersink a hole halfway through the 4x4.\nAnd then used a ¼” drill bit to drill the rest of the way through. I used a long drill bit because that's what I had lying around, but any drill bit longer than six inches should work.\nI made use to knock out all the shavings for a nice clean hole. I did this four times on each 4x4.", "56" ], [ "Deep Hole in a Small Box, a Different Take on the Infinity Mirror.\nIntroduction: Deep Hole in a Small Box, a Different Take on the Infinity Mirror.\nFirst off I must give credit for the inspiration to these two Reddit posts, this is the first one I saw and this is the one that inspired that first one.\nHaving seen these I knew it was something I wanted to make. I hope this Instructable inspires you to pick up the tools and give it a go.\nI completely messed up my first attempt by trying to use some beach and ash offcuts that I unsuccessfully jointed, this is version 2 and so much better.\nThe final product is impressive, even if I do say so myself.\nSupplies\nMost of the supplies will depend on the size of the box you're planning to make.\nI used some really nice B/BB plywood, this is such a great material and so different from the 'normal' plywood you get from the big box stores. Very few (if any) voids and with the B grade face it's pretty much blemish free. It's a little heavier and quite a bit more expensive, I would say it's worth it for any 'public' facing project.\nThe size of the box I made was determined by the mirror that my wife was throwing out, this was used as the bottom mirror.\nYou'll need enough wood (ply) to make the four side of the box to a height of about 325 mm (13 inches).\nI decided to go for a bulkhead light for the inside of the box as I thought this was in keeping with a mine shaft. You'll also need a length of mains cable.\nThe bottom mirror is a standard mirror but the top is where the 'magic' happens.\nStep 1: The Bottom Mirror\nTo reinforce the bottom mirror I mounted it to a piece of 4 mm plywood using some double-sided carpet tape.\nThis gave a total thickness of 8 mm, you'll need to remember this measurement for later as this is the size of the router bit you'll need for the rabbet.\nStep 2: Make Your Ladder\nI had originally planned to get an old ladder and chop one of the rungs off. After searching Gumtree, Facebook marketplace and local skips I didn't manage to find anything cheap enough (free).\nI wasted so much time looking around, it actually took me less time to make a quick single rung ladder.\nUsing a couple of 70 x 50 mm pine offcuts and an old broom handle I knocked up a little single rung ladder.\nI distressed the pine by knocking it about with a hammer and painted it black to add to the mine shaft authenticity.\nThe height of you ladder will be determined by the space between your two mirrors, you want to make sure the ladder is tight up against the top mirror as any large gap will ruin the illusion.", "787" ], [ "You also want to make sure the rung is in the middle for the same reason.\nStep 3: Making the Box Sides\nAs I do with most projects I drew up the basic plan first. I've attached the Sketchup file of the plywood layout.\nFor added strength I decided to join the sides using super sized finger joints, to do this I made a quick jig, this allowed me to make multiple blade passes on my table saw, these were also at an exact 90º.\nI started by measuring the end of the long sides and dividing it by 5 to get the size of the fingers. These were then marked out on both ends of the two longer sides. Once I had made the cuts to make the fingers I then used the cutouts to mark up the corresponding fingers on the short side pieces.\nUsing the cutouts to mark up the second pieces ensures that the fingers line up.\nI dry fitted the box together to ensure a good fit before the glue up.\nStep 4: Routing the Slot for Top and Bottom Mirrors\nUsing an 8 mm router bit mounted into my router table I routed a slot for the bottom mirror around the bottom of each of the four sides. In the shorter sides this slot was stopped before the edge, so I was not visible from the outside.\nIn one of the short sides I cut a 50 mm hole, this is centred around the bottom mirror slot, it's to allow the mains cable to pass past the mirror, through to the light.\nAgain, another dry fit, this time with the mirror in place.\nI then routed a slot all around the top edge of each side, this slot was 4.5 mm deep as I was planning to use a 4 mm top mirror. The slot was cut to half the width of the sides, this gives the top mirror enough area to rest on.\nAll the top slots were stopped to line up with the corresponding slot on the joined piece.", "599" ], [ "My Favourite Joinery Method for Plywood, MDF & OSB\nIntroduction: My Favourite Joinery Method for Plywood, MDF & OSB\nSheet material such as Plywood, MDF and OSB are fantastic to work with. They are really versatile and easily available at your local DIY hardware store. The awkwardness comes when it's time to decide what joinery method to use. So in this post I'm going to show you my favourite joinery method for sheet material.\nI've always liked the simple solution to problems and I think this joinery method couldn't get any simpler. It uses a router. a slot cutting router bit and some pieces of 6mm MDF.\nSupplies\nTools & Materials Used:\n* Router\n* Slot Cutting Router Bit\n* 6mm MDF\n* Wood Glue\nStep 1: The Star of the Show\nThe star of the show is the slot cutting router bit itself. The bit that I use has a cutting width of 6.3mm and a cutting depth of 9.5mm. I find this works great for joinery on 18mm material. The 6.3mm cutting width is a perfect fit for use with 6mm MDF. I cut my own MDF strips for use with this joinery method.\nStep 2: How to Make the MDF Pieces\nTo make the MDF strips I simple cut scrap pieces of MDF to 18mm wide strips. I then sanded them on the belt sander, slightly easing the edges to add a chamfer. This helps the MDF strips slip into the slots easier. Especially when wood glue is added. They can be cut to exact lengths for each joint or cut into smaller pieces and stacked next to each other to fill the slot.\nStep 3: Set Up the Router\nThe beauty of this method is that you don't have to be super precise with set up. I install the slot cutting router bit into the router and set the depth by eye to roughly centre on the sheet material I'm working with. As long as you reference the same side with the base of the router then the pieces will slot together perfectly flush, regardless of how far off centre you are.\nStep 4: Cut the Slots\nCutting the slot in the workpiece is simple, thanks to the bearing guided bit. There is no need for a fence or any other alignment jig. I simply start the groove away from the edge and ease the bit out before reaching the other edge. The slot can be cut in the same way on the mating piece.", "599" ], [ "Easing in and out at either edge so the slot isn't visible from the sides.\nStep 5: Add the MDF Pieces\nThe MDF pieces can then be added to the slot. For this example I didn't use any wood glue but typically, you would add wood glue to the slots and the MDF pieces before assembly. When wood glue is added the MDF swells slightly and makes for an even tighter joint. It's then just a case of slotting the pieces together. Add clamps while the glue dries and you're left with a perfectly flush joint.\nStep 6: 90 Degree Joinery\nThis joinery method even works for 90 degree joints. The first part of the joint is cut exactly the same way as before. The workpiece lay flat and the slot cut along the edge.\nThe mating piece needs the slot cut in the face of the material rather than the edge. This is a little awkward but it's still simple with the right set up. I clamp the workpiece in the jaws of my workbench in an upright position. A vise works great too. Behind the workpiece I add some scrap material. This is to help stabilise the router base as 18mm material is quite thin and the router base can rock slightly. With this secure it's just a case of cutting the slot. Again, easing in and out before reaching each end.\nChip out isn't a huge issue because it's inside the joint and will never be seen but you could use some painters tape to help prevent this from happening. If you're working with MDF you don't have to worry about this at all.\nWith the slots cut it's just a case of adding wood glue and the MDF strips into place. If you need to remove a strip for any reason and you're finding it difficult. Then the claw side of a claw hammer works great to lift it out. Then the pieces can be slotted together forming a 90 degree joint that is perfectly flush on the outside.\nStep 7: Other Methods: Screws & Dowels\nThere are of course lots of different joinery methods you could use with sheet material. Another one that I like is ideal for when it doesn't matter what the joint looks like. I use glue and screws at the corners of drawers, leave the glue to dry and then replace the screws with wooden dowels.", "599" ], [ "How to Make a Cheap Spotlight With Telescoping Stand From a Curtain Rod\nIntroduction: How to Make a Cheap Spotlight With Telescoping Stand From a Curtain Rod\nI made this spotlight so that I could make my YouTube videos using a single light source. When I film I like to isolate the subject as much as I can so that the viewer has no choice but to focus on what is in frame. When I first started making YouTube videos I would just film in my garage with the garage lights on which was fine but you could see all the miscellaneous items in the background. I felt this was distracting so I started trying to film with just one light source. This worked okay but there was still a lot of light bleed in the background. The miscellaneous junk in the background could still be seen just in dimmer light. So I came up with this idea to make a spot light that could be moved around that wouldn't take up a large foot print like a tripod. This is a fairly inexpensive build since I used an old curtain rod that I had in my attic and the rest of the materials aren't very expensive.\nSupplies\nRound Curtain Rod\n3 inch screws\nDrill w/drill bits and drivers\n1/4\"-20 Tap and Drill\n1/4\"-20 Screw with Knob\n1/2\" screws\nScrap Wood 12\"x12\"\n5 gallon Bucket\n9 quart Bucket\nGarden Trowel\n1 60lb. Bag Cement\nSpring Clamps\nLevel\nGloves\nClamped Work Light\nVise\nWork Bench\nHammer\nAluminum Flashing\nBlue Tape\nBlack Spray Paint\nYellow Spray Paint\nSharpie Marker\nRuler or Straight Edge\nPliers\nLight Bulb\nPPE\nStep 1:\nFor the stand I used an old curtain rod that I had in my attic that could be expanded in length, one rod fits inside of the other making adjustable by sliding it in and out. I first drilled several pilot holes in the bottom of the largest of the two rods we will call this the \"lower rod\" of the stand. Then I partially screwed in the screws. These are just randomly spaced around the bottom these will help the cement attach securely to the rod. Basically you want to create something for the cement to grab on too. The screw length isn't super important as long as its at least an inch long. Screw type doesn't matter either as you can see in the last pic there are a couple of types of screws that I used for this part.\nStep 2:\nOn the same lower I drilled and tapped a 1/4\"-20 hole. This will be for the adjustment knob. This did eventually fail after a lot of usage.", "582" ], [ "The thin wall of the curtain rod just isn't strong enough to take repeated use. Eventually I ended up welding a small 1/4\"-20 nut over the hole that could take the abuse. If you don't have a welder you can probably get away with using some 2 part Metal Epoxy like JB Weld to secure a nut to the rod. I also bought a better knob as the small one I had originally used was difficult to tighten due to its small size, I couldn't get much leverage resulting in loose rods, this actual knob works much better.\nStep 3:\nIn order for the rod to sit straight up and down I took a piece of 1/4\" scrap plywood and drilled a hole the same diameter as the rod. This scrap piece will help make sure the rod sits vertically while the cement dries this will make more sense in a later step.\nStep 4:\nNext I mixed up some cement in a 5 gallon bucket and filled the 9 quart bucket with the lower rod held in place.\nStep 5:\nNext I slid my scrap piece of plywood over the lower rod and let it sit on the top of the 9 qt. bucket. I checked it for square with my level and used some spring clamps to secure the plywood in place. This took a little bit of adjustment but eventually I was able to get it pretty close to vertical. I let cement cure overnight.\nStep 6:\nOn the smaller rod, the upper rod, I taped off a 3-4 inch section and painted it yellow. This will serve as a height indicator of sorts. When I am raising the upper rod and see the yellow part I will know to stop so that I don't pull the upper rod completely out of the lower rod. Its basically my max height adjustment indicator.\nStep 7:\nThe first pic shows my setup. In the second and third pics you can see the up and down adjustment of the stand. The stand worked great and was easy to adjust. The bucket was not very large so it didn't take up a large footprint and couldn't be kicked over by accident either. Overall I was happy with the stand. The light on the other hand was a whole other story.", "220" ], [ "How to Make Handscrew Clamps\nIntroduction: How to Make Handscrew Clamps\nI've always liked these handscrew clamps and own a pair but sometimes they are too big and a bit cumbersome. So I decided to make a smaller pair for smaller clamping jobs. Mainly I want to use these for work holding or for holding small diameter dowels when cutting them on the bandsaw.\nSupplies\n3/4 inch Square Hardwood\n1/4 inch Brass rod\n3/8 inch Brass Tube\n3/8 inch Mild Steel Rod\nBarrel Nuts\n1/4 - 20 Right Hand Tap and Die\n1/4 - 20 Left Hand Tap and Die\nTable Saw\nLathe\nLathe Tools\nDrill\nDrill press\nDrill Vice\nHacksaw or Portable Bandsaw for cutting metal\nBelt Sander\nVarious Grit Sand Paper\n25/64 inch Drill Bit\n5/16 inch Drill Bit\n3/8 inch Drill Bit\nBench Vice\nCenter Punch\nBlow Torch\nBrass Wire Brush\nDanish Tung Oil\nStep 1:\nI first prepped the wood, in this case its some 3/4 inch Walnut stock that I used. I ran the pieces through my table saw to make sure they were 3/4 inch square then I marked and cut some 4\" pieces. I used my belt sander to sand all four sides and make sure they were parallel to one another.\nStep 2:\nI have to be honest here before making these I had no real idea of how these worked so I sort of had to figure it out as I went along. They are fairly simple but I had never really put much thought in to the mechanism of their operation.\nI bought some barrel nuts aka cross dowel nuts that I used to mock up their location on the wood blanks. When I found what looked about right I marked the wood for drilling. Their location isn't really crucial as long as you stay above the half way mark of the length of the wood and space them evenly. Also make sure the holes are drilled in the same location on both pieces of wood. The barrel nuts were 25/64 inch in diameter so I drilled those four holes first. Initially I thought I would be using four purchased barrel nuts for each clamp, later I realized I had to make my own for one side.\nAfter making the holes for the barrel nuts I next transferred the lines to the adjacent side of the wood in order to drill the holes for the screw portion. I used a 5/16 inch drill bit for these holes. You can see in the last pic the eight holes drilled in each piece.", "582" ], [ "You will also notice that the 5/16 inch holes are elongated this is to allow for some play side to side where the threaded rods come through. To elongate the holes I just twisted the wood blank up and down while drilling. This could also be done with a router but I chose to use the side of the drill bit.\nStep 3:\nI cut a 12 inch brass rod in to two equal sections using my portable bandsaw table.\nA little bit of a disclaimer I am skipping my mistakes and getting to what I eventually figured out after some trial and error and a little research. I wasted about 2 feet of brass rod in my experimentation, I really should have just done the research before my first attempt and saved some time and material.\nStep 4:\nThe first picture shows you a threaded brass rod and a brass rod with some markings. In order to get these clamps to work the screw portion has to have two different thread types, one half has a right hand thread, your traditional thread righty tighty lefty loosey, and the other half has a left hand thread. The rod with the markings shows an exaggerated view of what the threading on the rod actually looks like. This threading is necessary if you want the clamps to work like the traditional ones where you can hold the handles and spin them like a bicycle crank. In order to accomplish this you need two thread cutting dies a Right Hand thread cutting die and a Left Hand cutting die. You will also need a Left Hand tap as well because a left hand threaded screw will not screw in to a right hand threaded nut.\nStep 5:\nI used my bench vise to hold the thread dies. I made sure to round off the ends of the brass rods so they would find the die center more easily. Next I chucked the brass rods in my hand drill and ran them through the right hand thread cutting die but only to the half way point of the brass rod. Then I removed the brass rod from the drill flipped it over end over end and chucked it back up in my hand drill and ran the brass rod through the left hand thread cutting die up to the half way point. I left a tiny section of brass rod right in the middle that was left untouched by either die.", "56" ], [ "Modern Geometric Candle Holders\nIntroduction: Modern Geometric Candle Holders\nWood prices have nearly tripled recently. This makes it the perfect time to hunt and scavenge for free materials. The wood for these candle holders was rescued from a construction site dumpster and turned into these modern geometric candleholders. They are fun to make and very fast and easy to batch out making them a very good product to sell. Back when local craft shows were a thing before the lock down these candle holders were one of my best selling products and would sell out almost immediately.\nThis project truly embodies the spirit of Trash to Treasure as I turned wood headed for a landfill into a product that customers loved and generates profit to fund future projects and tools.\nUsing a few basic tools found in most small garage woodshops, I will show you how to build a few of these Geometric Candle Holders of your very own.\nIf you would like a copy of the template I designed I have a link to it in the video description.\nSupplies\n2 x 3 Dimensional Lumber\nPolycrylic Clear Matte\nTea Light Candles\nHot Glue\nMaking Tape\nSandpaper\n3 inch Nails\nStryofoam Sheet\nColor Spray Paint (optional)\nStep 1: Getting Started\nThe wood for this project came from two, roughly four foot sections of 2x3's I found in a construction site dumpster. I spoke with the construction crew and asked if it would be ok to take a few pieces and they gave me the go ahead. I always ask before I take any material from construction sites just to be sure it's ok.\nI started this project by printing and laminating a copy of the template I made. Laminating the template isn't required, but it does keep the template from ripping and tearing when using it multiple times. I've made hundreds of these candle holders using the same laminated template! With the template laminated I cut it out using a hobby knife.\nStep 2: Cutting the Blanks\nI marked out a line on my miter saw fence 8 inches away from the blade. Using a clamp and a scrap of wood I clamp it to my miter saw fence. This will allow me to butt up my wood to the stop block and make repeated cuts over and over again without having to measure every time.\nI cut both 2x3's into 8 inch long blanks.", "401" ], [ "I was able to get 10 blanks out of both pieces with very little wood left over.\nStep 3: Drilling the Holes\nWith the blanks cut to size I chose which face I wanted for the top. I tried to avoid any knots or major defects. Once I chose my top I lined the template up to the blank and transferred the center mark using a scratch awl. This left me with three impressions I will use at the drill press. I repeated this process until all of the blanks had marks on the tops.\nWith a 1 and 5/8ths inch forstner bit chucked up in my drill press I lined up the center of the bit with the marks I made and drilled three holes into each candle holder blank.\n**Pro Tip**\nSave those wood shavings! You can make so many cool things with them, like the Water Resistant Fire Starters I showed you how to make in a previous Instructable found here\nhttps://www.instructables.com/Cheap-Water-Resistant-Fire-Starters/\nStep 4: Creating the Facets\nI set my miter saw fence to random degrees and cut the ends of the blanks into random angles. I switched the angle every two or so cuts as I wanted a lot of variation between the candle holders. To further randomize the angles I also tilted the blade to random angles. This process leaves the candle holders with really nice randomized facets on the ends.\nStep 5: Cutting Randomized Side Profiles\nUsing the cut off scraps from the miter saw, I attached them to the bottom of the candle holders using masking tape. This will give me a random side profile when I run them through the bandsaw. When cutting the sides on the bandsaw, I kept constant downward pressure on the middle of the piece so that it wouldn't pivot under the pressure from the blade.\nAfter cutting one side I removed the cut offs, mixed them up, reattached them to the candle holders, and cut the other side.\nAlternatively you could tilt the table on your bandsaw, but I like how random the cuts turn out using the cut off method.\nStep 6: Sand the Pieces Smooth\nI use my belt sander to remove all of the band saw marks and sand the pieces smooth. To sand the faceted ends I used the disc sander attached to my belt sander and adjusted the angle to match the angle of the facet.", "599" ] ]

[ 9959, 5724, 3740, 7449, 7225, 2909, 10981, 10700, 11169, 5309, 5880, 10348, 4507, 2162, 8821, 9075, 10636, 10970, 1095, 6105, 10340, 7682, 6755, 558, 5271, 5528, 10400, 10735, 6934, 2711, 10856, 5095, 6502, 6386, 8043, 2605, 10263, 325, 2337, 10114, 8836, 3050, 7338, 8783, 11371, 7012, 4599, 1880, 5207, 6341, 9425, 3877, 6935, 4508, 1938, 6292, 1688, 1981, 4825, 4701, 6566, 10779, 4836, 1099, 9145, 8363, 8939, 205, 11150, 6849 ]

[ [ "<PERSON> Blue Cake (Brooklyn 99) With Secret Gummy Bears\nIntroduction: <PERSON> Blue Cake (Brooklyn 99) With Secret Gummy Bears\nSo this is my version of <PERSON>'s blue cake from the tv show Brooklyn 99. I thought to make it more worthy of <PERSON> I thought I would add a secret layer of gummy bears into the middle layer of the cake. What would make cake better than adding more candy right??\nThis is a really fun recipe to make if you like watching Brooklyn 99 and it is really fun to make and you can share it with your friends next time you watch the show :D\nStep 1: Ingredients and Equipment\nIngredients\nFor the cake\n- 112.5g or 1/2 Cup Unsalted butter, room temperature\n- 1 Cup caster sugar\n- 1 + 3/4 Cups plain flour\n- 2 1/2 tsp baking powder\n- 3/4 Cups milk\n- 1 Egg at room temperature\n- 1-2 tsp vanilla bean paste/extract (you can use just one but I always like to add more vanilla it is delicious!)\n- 1 tsp salt\n- 2 Tbsp canola oil (or any flavourless oil)\n- Blue food colouring\nfor the Filling / Frosting\n- 112.5g / 1/2 Cup unsalted butter,\n- 3 Cups of icing sugar\n- 1-2 tsp vanilla extract / bean paste\n- 3 Tbsp milk\n- Blue and Black food colouring\n- Gummy bears (enough to make a full flat layer of them on the cake at least one packet.) Also, ensure you have a couple of extra handfuls for decorating each slice after.\n- A pinch of salt to balance the sweetness if you want.\nEquipment\n- 2 x (20cm diameter) round baking tins\n- Baking paper\n- Scissors\n- Spatula/plate scraper\n- Electric mixer and bowl with a paddle attachment\n- Small bowls for your icing\n- 2 different piping tips (I went for a star like one for the piping around the cake, and a small 2mm piping tip for writing happy birthday on the cake)\n- Piping bags\n- 3 candles (ideally blue, pink and yellow like in the show.)\nStep 2: Make the Wet Mix of the Cake\nFirst take your unsalted butter and place it in your standing mixer and beat it for a few minutes until it becomes lighter and fluffier in texture (about 2-3 minutes). Then add the caster sugar in small amounts, continuing to mix until the mixture becomes even lighter and fluffier than before! Don't forget to scrape down the sides to make sure it all combines properly!.\nAfter beating for about 5 minutes we are then going to add the egg and vanilla and continue to mix on a high setting for about 5-10 minutes until it becomes, once again lighter and fluffier than before! You want the mixture to be a bit smooth and not grainy (test this by rubbing some between your fingers, it does not have to be completely smooth but ensure it feels nice and fluffy and well incorporated).\nStep 3: Make the Dry Mix and Add It!\nNow to make the dry mixture either sift together or place the salt, flour and baking powder into a bowl and mix together with a whisk (i prefer this as it prevents lumps and it is less messy than sifting).\nThen we are going to add 1/3 of the flour mixture to the wet mixture we have just made and mix it on a low speed. then add 1/3 of the milk and mix again.", "305" ], [ "continue to add the dry mix and milk in alternating batches until all added. You want to do this in alternating amounts to prevent lumps from forming and ensure a good consistency of the cake. (also don't forget to scrape down the sides of the bowl in between additions).\nThen add the oil and blue food colouring until you get a nice light blue colour and continue to mix until it is all incorporated. Make sure you scrape the sides of the bowl when you add the colour because if you don't there will still be white cake mix on the edged! we want a uniform blue colour (get it because they are policemen XD).\nStep 4: Line Your Cake Pans\nA little trick to line your 20cm round cake tins perfectly without overhand is to fold your piece of baking paper in half then in half again to make a small square. Then fold into a triangle twice and then line it up with the base of your cake tin from the centre of the tin to the edge. cut the paper at the edge of the tin, unfold it and voila a perfect circle lining for the base of your tin! Magic! If you need to add some butter or non-stick spray to make sure it lies down flat.\nStep 5: Bake the Cakes!", "891" ], [ "Pumkin Oatmeal Cream Pies With a Maple Cream Cheese Filling\nIntroduction: Pumkin Oatmeal Cream Pies With a Maple Cream Cheese Filling\nEvery one of us has probably heard of those Little Debbie Oatmeal Cream Pies and most of use probably ate them every chance we could, trust me I'm guilty as well. this Instructable will show you how to make Oatmeal Cream Pies but with a pumpkin and maple cream cheese twist.\nStep 1: Gather the Ingredients\nFor this version of the Oatmeal Cream Pie you are going to need these ingredients. One thing you also could do while you are getting your ingredients out is preheat your oven to 375 degrees Fahrenheit.\n* 2 1/2 sticks of unsalted butter, make sure to get this out first so by the time you are ready to start mixing the ingredients together it is at room temperature.\n* 1 cup of Brown sugar\n* 1/2 cup of granulated sugar\n* 1 large egg, make sure to get this out with the butter so that it also becomes room temperature.\n* 2 tsp of molasses\n* 1/4 of a cup of pumpkin puree, you don't have to use the pumpkin if you don't want to have pumpkin in the cookie part.\n* 2 tsp of pure vanilla extract\n* 2 tsp of maple extract, this ingredient is also optional along with the pumpkin puree if you just want to have a normal homemade oatmeal cream pie.\n* 1 1/2 cups of all purpose flower\n* 1 tsp of baking soda\n* 1/2 tsp of salt\n* 1/4 tsp of ground cinnamon\n* 1/4 tsp of ground nutmeg\n* 1/4 tsp of ground cloves\n* 3 cups of quick cooking oats, if using whole oats, grind them down to a fine powder\nMaple Cream Cheese Filling\n* 1 1/2 sticks of unsalted butter, make sure this is also room temperature\n* 8 oz. of softened cream cheese\n* 3 cups of confectioners sugar\n* 1 tsp of pure vanilla extract\n* 1 tsp of maple extract, (you do not have to use if you do not want a maple cream cheese filling)\n* only a pinch of salt\nStep 2: Mix the Butter and Sugars\nIn a large mixer put the butter and sugars in the mixer and mix on medium to high speed until creamy. Then add the egg and vanilla and maple extract, molasses , and pumpkin puree, make sure you are scraping the sides when ingredients cling to the wall of the mixer bowl. make sure all ingredients are mixed together fully before moving to next step.\nStep 3: Make Dry Mixture\nIn a different bowl, mix the flour,baking soda, salt cinnamon, nutmeg and cloves.\nWhile the mixer is mixing on low slowly add the dry ingredients, make sure to do it at different times preferably when the dry ingredient amount is fully mixed in.\nStep 4: Mix Oats Into Dough\nWhen all of the dry ingredients are mixed with the wet add the oats.", "305" ], [ "do not use the mixer to mix the oats in make sure you use a rubber spatula until completely mixed (or do not see any white from the oats being dry).\nStep 5: Put Cookies in Oven\nBy now the oven should be fully heated but before you put the dough in put the raw dough on a rubber cookie sheet or parchment paper. Make sure the cookies are also spaced out about 2-3 inches because they will spread in the oven. Scoop the dough out with a large cookie scoop, if you don't have access to one just use two table spoons full as a measurement. If you are not using the Quick oats then you can probably get away with spacing the cookies 2 inches apart because whole ground oats will not cause it to spread as bad but make sure you flatten them with moist fingers or gently press them down fresh out of the oven with the bottom of a glass.\nStep 6: Bake Cookies\nBake cookies for 10 minutes.\nStep 7: Make the Cream\nIn a large bowl beat the softened butter and cream cheese on a medium to high setting, I used a handheld mixer but you can use a stand mixer with a new bowl. make sure that when the butter and cream cheese is combined fully then add the confectioners sugar and beat on medium for about 2 minutes then add the maple extract and beat on high for 2-3 minutes until fluffy. give it a taste and add a pinch of alt as needed. Then spread desired amount onto cookies and sandwich the cream.", "891" ], [ "Heart Shaped Toad in the Hole\nIntroduction: Heart Shaped Toad in the Hole\nI thought for Valentine's day that I wanted to take a spin off the traditional toad in the hole breakfast and create a little heart filled delicious treat!\nThis recipe is super simple, and I have some tips to make it absolutely delicious, and almost anyone can make it! and it is such a sweet way to take breakfast to the next level. I hope you make it for the ones you care about or yourself if you want a special breakfast for yourself.\nSupplies\nIngredients\n- 2 large free-range eggs\n- 2 thick slices of white bread\n- 1 tbsp mayonnaise (I love using Kewpie mayo but any will do)\n- 1-2 tbsp high-quality butter\n- Salt and pepper to taste\n- Fresh chives or parsley, to serve\nEquipment\n- Heart-shaped cookie cutter (or a knife if you don’t have one)\n- Butter knife\n- Frying pan\n- Spatula\n- Serving plates and cutlery\nStep 1: Prepare the Bread\nThe first step of this recipe is to spread the mayonnaise on each side of the bread with a butter knife. I usually go for about 1-2tsp per side**. then take the heart-shaped cookie cutter and make a hole in the centre of the bread. if you do not have a cookie-cutter you can always use a knife to cut out a heart.\n**Note**\nYou are probably wondering why mayonnaise?? well the fat content and slight tang of mayonnaise gives a beautiful flavour, plus the fat content also helps to make the bread incredibly crispy, whilst moist. YOU NEED TO TRY THIS TRICK!! (it works great for grilled cheese too).\nStep 2: Fry the Bread\nOn medium to low heat add about a tablespoon of high-quality butter** to a frying pan and allow to melt.", "22" ], [ "Then add the bread and the little heart cut out into the pan and allow it to cook until it is golden and toasty this may take a few minutes. (cook this according to how toasty you like your toast). Then flip the bread over.\nStep 3: Cook the Egg\nBefore adding the egg you may want to add some more butter but this is a personal preference. Then slowly add the egg into the heart-shaped hole and cook on medium heat until the egg is cooked to your liking. This will look the best sunny side up (shown above) because you get the beautiful shape and colour contrast, this will take about 3-4 minutes.\nOf course, if you like yours cooked more then I would try and flip it carefully to try and keep the egg contained within the hole. if you flip it too fast the white will go over the bread and you will lose your heart shape.\nStep 4: Serve\nServe immediately whilst it is nice and hot and sprinkle on some freshly chopped chives or parsley and top with salt and freshly cracked pepper.", "405" ], [ "Galaxy Macarons\nIntroduction: Galaxy Macarons\nThis lovely galaxy-themed macarons are a deliciously and stunning cookie you can make to take your friends to a galaxy far far away! They are also gluten free!!\nSupplies\nIngredients\nMacaron Shell:\n* 200g Sifted Almond meal (You will need more as you will sift out lumps)\n* 200g Pure Icing sugar (again may need slightly more) (It is important to use our icing sugar as using icing mixture can change the texture, this step also makes it gluten-free)\n* 80g Old egg whites, room temp (old egg whites refer to separated egg whites that have been cracked 3-5 days beforehand, covered in a cling wrapped container. this gives a better meringue)\n* 70g Fresh egg whites, room temp (cracked at the time)\n* 50ml water\n* 200g caster sugar\n* Edible food colouring (ideally gel or powdered, not liquid)\nFilling:\n* Use any filling that you like, such as a chocolate-based ganache or salted caramel, I have a separate video for the salted caramel but the ingredients are.\n* 250g caster sugar\n* 70ml water\n* 120ml thickened cream\n* 200g butter\n* 1-2 tsp vanilla bean paste\n* 1-2 tsp salt (I recommend trying this and adding more salt than you think, the shells are quite sweet, therefore having a salty filling complements the flavour really well)\nEquipment:\n* Small saucepans\n* candy thermometer\n* standing mixer with the whisk attachment and metal mixing bowl\n* oven\n* spatula/scraper\n* circle macaron print templates (I use one off of google images with XXXcm diameter circles)\n* Baking paper (NOT wax paper)\n* Piping bags 11mm round piping tip\n* toothpicks or skewers\n* Whisk\nStep 1: Make Your Filling\nI typically make the filling for my macarons the night before I make my macarons so that it can chill adequately.\nI have a separate full video for this on my channel but here are the pictures\nFor the salted caramel filling:\nPlace the 250g caster sugar and 70ml water in a small saucepot and put on high heat until it changes colour. For a sweeter caramel let it go yellow, for a slightly bitter caramel let it go darker (I recommend this as the darker more bitter caramel tastes lovey with the sweet macaron shell).\nOnce it changes colour, immediately whisk in the thickened cream (WARNING) This will steam quickly so be careful not to burn yourself. Then whilst mixing, add a candy thermometer and allow it to come to 108 degrees Celcius (226.4F). Immediately place the pot into cold water to stop the caramel from getting hotter.\nOnce cooled for a minute, add the vanilla bean paste, salt and whisk in half of the butter. (do this quickly so that the butter doesn't melt and separate from the caramel). Then add the rest of the butter and whisk. taste it and make sure it is to your liking.", "305" ], [ "I would make it slightly saltier than expected as the shells are quite sweet.\nYou can fill them with any delicious filling and I have some other options on my channel if you want to try different ones.\nSuch as raspberry and white chocolate ganache, vanilla white chocolate ganache etc.\nStep 2: Prepare Dry Ingredients\nIn a large metal, bowl sift/whisk together the almond meal and pure icing sugar.\nStep 3: Make the Meringue\nPrepare a standing mixer with a whisk attachment and metal mixing bowl. Ensure the bowl is properly clean with no water, dust or oils, it needs to be clean for a good meringue.\nIn a small saucepan heat 200g caster sugar and 50ml water to a boil. With a candy thermometer heat it up to 117.5 Degrees Celcius (243F). Once it reaches this temperature immediately plunge the pot into cold water to stop the sugar syrup from heating up further. Once the syrup stops making small bubbles it is ready to add to the egg whites.\nOn a medium-high speed quickly beat the egg whites for 30 seconds. Then slowly drizzle in the hot sugar syrup so that\n1. The egg whites don't cook\n2. the sugar syrup does not clump and cool on the bowl\nThen continue to beat the meringue on a high speed for about 8-10 minutes, or more until it creates stiff peaks and that the bowl is cool to the touch.\nStep 4:\nIn the metal bowl with the dry ingredients add the 70g new egg whites and mix them all together to form a paste. Then slowly fold in half of the meringue into the mixture.", "136" ], [ "Gluten and Dairy Free Triple Chocolate Roll\nIntroduction: Gluten and Dairy Free Triple Chocolate Roll\nIt's my pleasure to present to you a chocolate inspired recipe from my late Mum, slightly modified to suit the needs of my gluten and dairy intolerant daughter.\nFilled with a luscious chestnut cream, I promise you, NOBODY will ever be able to guess that this chocolate treat is gluten and dairy free.\nLet's begin...\nSupplies\nSPONGE CAKE:\n* 40g unsweetened cocoa powder\n* 1 tablespoon cornstarch (or potato starch)\n* 1/8 teaspoon salt\n* 6 large eggs, separated\n* 150g granulated sugar (separated into 125g and 25g)\n* 1 1/2 teaspoons vanilla extract\n* 1 tablespoon dark rum (optional)\n* Icing sugar for dusting\nCHESTNUT BUTTER CREAM FILLING\n* 75g softened, unsalted margarine (can substitute for butter)\n* 25g softened coconut oil (can substitute for more margarine or butter)\n* 100g sweetened vanilla chestnut spread (also known as chestnut puree)\nCHOCOLATE FROSTING\n* 50g unsalted, softened margarine (or butter)\n* 50g vanilla chestnut spread\n* 75g 60-70% dark chocolate, melted\nDECORATION (optional)\n* 50g white chocolate, melted\n* Fresh fruit, berries (whatever is in season)\n* Cocoa powder or icing sugar\nTOOLS / UTENSILS\n* Measuring spoons\n* Spatulas\n* Scissors\n* Bowls\n* Weighing scale\n* Swiss roll tray, greased and lined with parchment / greaseproof paper\n* Stand mixer with whisk attachment\n* Hand whisk\n* Tea towel\n* Cooling rack\nStep 1: Let's Get Beating\nPreheat the oven to 190°C / 375°F.\nGrease and line a Swiss roll tray with parchment / greaseproof paper. This will make it easier to remove and roll the sponge later.\nCombine the cocoa powder, cornstarch and salt in a bowl and set aside.\nWith the separated egg whites, start to whisk until they form soft peaks. Gradually add in the 25g of sugar and beat until they form stiff peaks.\nStep 2: Now It's Time for Chocoate\nIn a separate bowl, beat the egg yolks with the remaining 125g of sugar until pale and thick.\nAdd in the vanilla, (optional) rum and cocoa starch mixture.\nNow carefully fold the stiff egg whites into the chocolate mixture and gently spread out the batter onto the lined Swiss roll tray.\nBake in the preheated oven for 12-15 minutes, until the cake springs back to a light finger touch and is just starting to shrink a little from the edges of the tray.\nBE CAREFUL not to overcook, otherwise the sponge will crack when rolling.\nStep 3: Let's Roll With It\nOnce the sponge is baked, remove from the oven and immediately dust the top of the sponge liberally with icing sugar.\nRun a blade around the edges and cover with a clean kitchen towel, then a wire rack (with feet facing up).\nReverse the tray and rack together and lift off the tray, revealing the underside of the sponge (greaseproof paper up).\nCarefully slide the kitchen towel and sponge onto a flat surface and slowly peel off the greaseproof paper.\nTrim any crispy edges and quickly gobble them up! If anyone asks, you are taste testing :-)\nStarting at one of the short edges, roll the cake up, then leave to cool for 20 minutes.\nStep 4: Fill Her Up\nWhisk together the butter, coconut oil (if using) and chestnut spread until smooth.\nNOTE: For those who live in a warm climate or a warm home, you can place the filling in the fridge until the sponge is cool.", "305" ], [ "This will allow the filling to hard a little. Just don't forget to whisk again before using.\nUnroll the sponge onto a sheet of greaseproof paper, removing the kitchen towel.\nSpread the chestnut filling all over the sponge in an even layer, leaving a 1-2 cm band on one of the short edges.\nUsing the greaseproof paper and starting at the short edge that is frosted, roll the sponge up again and transfer to a flat surface/ plate and pop it into the freezer for 10-15 minutes. This will make it easier to frost later.\nStep 5: A Little Bit Frosty\nMelt the dark chocolate and butter and then beat in the chestnut spread.", "136" ], [ "Warm Spinach Dip Cobb Loaf\nIntroduction: Warm Spinach Dip Cobb Loaf\nThis cobb loaf is an absolute staple for any good party in Australia. We go absolutely nuts over it! why you ask?? because it is cheesy, warm, wholesome and toasty!!!! Just try it! you won't regret it.\nStep 1: Ingredients and Equipment\nIngredients\n- 1 Tbsp of Olive oil (you can also use 2 for a richer filling)\n- 250g Cream cheese (room temperature)\n- 1/4 cup Mozzarella cheese (for the top for extra cheesiness - you can omit this, but don't because of cheese)\n- 1/4 cup of milk (we are adding this in halves to make sure the mixture doesn't get watery (always start with less and add more)\n- 250g Frozen spinach, that has been thawed and squeezed of any excess water\n- 1/2 cup parmesan cheese (please add more if you want this is a minimum for flavour- I usually add more because of cheese yumminess).\n- 1/4 cup of Sour cream\n- 1 medium Brown onion, diced fine\n- 2 cloves of garlic, crushed\n- 1/4 tsp nutmeg\n- Salt and pepper to taste (i use 1/2tsp of each, this depends on how much cheese you add and how salty your cheese is).\n- 1 Whole cob loaf + more (I usually have more bread to toast alongside this or some crackers to feed more people)\nEquipment\n- Bread knife\n- Oven and Baking tray\nStep 2: Filling: Fry the Onions\nFirst, to make our delicious filling we are going to free the onion in the olive oil on medium-high heat until they are nice and brown (about 5 minutes) *. Then add the garlic and stir for about a minute until it becomes aromatic and delicious!\n* Add a pinch of salt to your onions, this can help draw out moisture and brown them faster.\nStep 3: Filling: Add the Rest\nOnce your onions and garlic are sauteed add half of your milk and mix it into the onions. Then add all the cream cheese and 'smoosh' it all together (this is the best way I can describe this action).", "265" ], [ "Once the cream cheese is slightly melted add the sour cream, spinach, remaining milk, parmesan cheese, salt, pepper and nutmeg and stir until all mixed together. Make sure that you try this and add any more seasoning if you wish.\nStep 4: Prepare the Bread\nWith a bread knife slice off the top of the bread (like a little hat or lid to a bowl). Then cute or pull out the inside of the bread and tear it apart (this is what people will dip with). I usually have a few extra bread rolls to toast alongside this so that you can have more bread to dip into the amazing filling!!\nThen place all the bread onto a baking tray.\nStep 5: Bake It!\nFill your hollowed out cobb loaf with the spinach dip and then add the mozzarella cheese on top (this will help it get extra golden brown and cheesy!!).\nThen bake the loaf in a preheated oven 200 degrees Celcius (400 degrees Fahrenheit) for about 5-8 minutes or until it is golden brown.\nStep 6: Serve It Hot\nThe best way to serve this is straight out of the oven! and the best part about it is that you can eat the bowl so there is little cleanup!!\nI hope you enjoy this and share it with your friends!!!", "195" ], [ "Blackberry Pie With Geometric Fruit Topping\nIntroduction: Blackberry Pie With Geometric Fruit Topping\nI love fruits but absolutely hate traditional fruit pies. Fruit always falls out of the crust, it’s too soggy, messy and not particularly attractive. This is my take on the traditional blackberry pie. In this recipe we cook and thicken the fruit before baking it in the oven. You can also strain the filling to remove pits and seeds for a smooth fruit pie.\nFor an 8 inch pie dish you will need:\nPie crust (store bought or home made)\n500g blackberries (other berries or mixed will work too)\n100-250g sugar\n2 tablespoons lemon juice\n35g cornflour\n30g butter\nFor mirror glaze:\n250g berries or 240ml berry juice\n2 teaspoons gelatine\n½ teaspoon cornflour\n2-3 tablespoons sugar\nFor fruit topping:\nVariation of fruits not prone to oxidation. 3-5 different coloured fruits such as: dragon fruit, papaya, mango, kiwi, coconut meat, red dragon fruit, strawberries, melon, pineapple, starfruit.\nStep 1: Pie Crust\nMaking a pie crust from scratch is well worth the trouble, but if you don’t feel like making it yourself, just use a ready-made one. Here’s a recipe for a fool-proof pie crust.\nWeigh out all the ingredients and leave them in a fridge for 1-2 hours to cool them as much as possible.\n170g flour\n1 tablespoon sugar\n1 teaspoon salt\n120g cubed butter\n¼ cup water\nPulse flour, sugar and salt in a food processor (or whisk everything together if making crust by hand). Add cubed butter and pulse a few times, until mixture resembles crumbs (or use pastry cutter https://www.lakeland.co.uk/72399/Stainless-Steel-... ). Add 2-4 tablespoons of cold water to the pastry and pulse a few times until the mixture resembles wet sand. Don’t over-mix it. Tip the mix onto a countertop and quickly combine the crumbs into a ball. Pastry should come together easily. Shape it into a flat disk, cover in cling film and put in the fridge immediately.", "69" ], [ "Leave it to cool for 1-2 hours.\nStep 2: Blackberry Filling\nIn a large pot, over medium heat, warm 500g blackberries, 100g sugar and ½ cup water until berries are soft and easily bruised. Mash the fruit using a fork or a potato masher. If you want to, you can pass it through a sieve to remove the seeds. I left mine in to have some crunch.\nAdd lemon juice and taste for sweetness, add more sugar if necessary and continue heating until sugar dissolves. Take it off the heat.\nMix 35g cornflour with a few tablespoons of cold water to create a slurry. Add that to the pot and whisk everything together, return to the stove and cook over medium heat. Whisk continuously to prevent burning. Continue cooking until bubbles form and berry mixture thickens (you can tell it’s thick enough if you run a finger through the back of the spoon and the mixture stays put and isn’t runny). Take it off the heat, stir in butter and mix until dissolved.\nLet it cool down, put the pot into a bowl of water to speed the cooling.\nTake the pastry out of the fridge and roll it out. Use a sprinkling of flour or roll it between parchment paper to prevent sticking. Line your pie dish, cut off the crust edges or crimp them. Use a tart tin with a removable base if you don’t have a shallow enough pie dish. Put the crust back into the fridge for 20-30min.\nStep 3: FIlling\nPreheat the oven.\nOnce the filling is cold spoon it into the dish and smooth the top. Bake immediately, we don’t want the butter in the pastry to melt.\nBake at 200°C (400°F) for 15 min\nAfter 15 min reduce the temperature to 180°C (350°F) and bake for 35-45 min.\nYou can cover the pie with aluminum foil half-way through the bake to prevent from burning.\nLeave it to cool completely.\nStep 4: Covering Mistakes With Fruit Glaze (Optional)\nI covered my pie with aluminum foil and once it was out of the oven I made a mistake and snagged the hot and still-not-set filling with the foil. I made a mess and there was no way of fixing it, so I decided to make a glaze to cover it up.\nFruit glaze is easy to make and can be used in cakes, tarts, pies and desserts.", "69" ], [ "Conchas- Mexican Sweet Bread\nIntroduction: Conchas- Mexican Sweet Bread\nMexican sweets and pastries never fail to cheer me up. They are delicious and visually stunning, not to mention highly coveted, because the sad truth is, they are not very popular in Europe. Since I can't pop into a bakery to get a box of conchas, I had to learn how to make them from scratch.\nConchas are sweet buns topped with a coloured, sugary, crumbly dough scored across to resemble a seashell. They are fluffy and moist with a crunchy topping. Perfect for a quick breakfast, lunch or a midnight snack.\nSupplies\nFor 12-14 medium buns:\nDough:\n* 400g bread flour (+1/2 cup for kneading)\n* 100g granulated sugar\n* one sachet dried yeast (2 teaspoons)\n* 1 teaspoon salt\n* 180ml warm, whole milk\n* 2 eggs, room temperature\n* 1 tablespoon vanilla extract\n* 80g softened butter\nColoured topping:\n* 150g softened butter\n* 150 g powdered sugar\n* 1 tablespoon vanilla extract\n* 180g all purpose flour\n* food colouring of choice; for brown use cocoa powder\nAdditionally:\n* cooking spray or few teaspoons of neutral oil (for oiling the bowl and oiling the buns)\n* very sharp knife, razor, clean utility knife or concha cutter\nhttps://www.amazon.com/Mexican-Cortador-Conchas-Di...\nStep 1: SWEET DOUGH\n1. Use a stand mixer and a dough hook attachment.\n2. Place flour, yeast, sugar and salt in the mixer bowl and mix it with a hand whisk.\n3. Add warm (NOT HOT) milk, vanilla extract and eggs. Turn the mixer on low and mix until the dough comes together, about 2-3 minutes.\n4. Add softened butter, continue mixing on low for 2-3 minutes, or until all butter is incorporated. If it becomes stuck to the bowl or the hook, scrape it with a spatula.\n5. Once combined, turn the mixer on high and let it knead for 8-12 min.\n6. The dough will be quite wet, but it should come off the sides of the bowl easily. Don't be tempted to add more flour, this dough is supposed to be sticky.\n7. Prepare a large bowl, oil it lightly on the inside and transfer the dough to the bowl. Cover with cling film and leave in a warm spot to double in size ( 1-2 hours)\nStep 2: DOUGH PROOFING\nSweet dough doubled in size.\nStep 3: SUGAR TOPPING DOUGH\n1. Make the sugar topping while the dough is proofing.\n2. Mix softened butter, vanilla extract and powdered sugar.", "305" ], [ "Once smooth, add the flour and mix thoroughly until it resembles cookie dough.\n3. Choose your colours, divide the dough equally and dye it in as many colours as you want. For brown colour use 1-2 tsp cocoa powder\n4. Wrap each colour in cling film and put aside.\nStep 4: BUN SHAPING\n1. Tip the dough onto a floured surface, sprinkle more flour on the top and knead it by hand for a few minutes until it deflates completely.\n2. Use a knife and a kitchen scale to divide the dough evenly. Make each bun between 60 and 90g. I made mine all 60g, once baked, they were medium sized and perfect for a snack.\n3. Shape the dough into even balls and place on a baking tray. Leave 2-3 inches of space between the balls.\n4. Spray each bun with cooking spray or brush them with a small amount of oil.\n5. When all the buns are shaped and placed on the baking tray move to the next step immediately before the buns have a chance to raise too much.\nStep 5: SUGAR TOPPING\n1. Cut a few square sheets of waxed paper (about 7x7in).\n2. Place a ball of dough (25-30g) in the middle of the square sheet, cover it with another sheet. Roll the dough out with a rolling pin, or place a large plate on top and press it down into the dough to flatten it and make it into a circle. The dough is very soft, so this step is super easy.\n3. Peel one square sheet off the dough, pick up the remaining sheet with the circular sugar topping and transfer it onto the bun. Cover the entire surface of the bun with the sugar disc and gently peel the waxed paper off the sugar topping.\n4. Use a glass or a round cookie cutter to trim the edges of the sugar topping to make it more even.", "195" ] ]

[ 7997, 988, 4810, 1123, 1197, 2964, 9500, 4510, 10428, 11360, 9157, 589, 3455, 9596, 9567, 365, 4239, 5673, 1989, 7665, 11037, 10388, 7263, 10581, 4436, 1246, 881, 7534, 9914, 9182, 9677, 6483, 10956, 10014, 7060, 9006, 1901, 9211, 11155, 10840, 11287, 6198, 1107, 3043, 1455, 4170, 4207, 2077, 8865, 67, 8558, 3795, 2282, 1585, 9770, 2520, 6111, 5172, 5187, 860, 9281, 11387, 3845, 5857, 6074, 10380, 8195, 5836, 10, 6862 ]

[ [ "Barometric Mason Jar\nIntroduction: Barometric Mason Jar\nWeather an everyday preoccupation over which we have no control but affects our daily lives in so many ways.\nHow do we know what the weather will be like from day to day, check the weather bulletins, look out of the window or monitor it yourself.\nUsing a STEAM approach you can create basic tools to aid in weather forecasting.\nScience - Any system of knowledge that is concerned with the physical world and its phenomena and that entails unbiased observations and systematic experimentation.\nTechnology - Methods, systems, and devices which are the result of scientific knowledge being used for practical purposes.\nEngineering - Scientific principles to design and build machines, structures, and other items.\nArts - The expression or application of human creative skill and imagination,\nMathematics - The abstract science of number, quantity, and space,\nWe will be observing the effects of the weather by using a device that responds to atmospheric pressure and by gathering and analysing the data gain an insight into the relationship between the two.\nOne simple method to monitoring atmospheric pressure is a Barometer were we can get an indication of the likely weather conditions.\nBarometer, a device for measuring atmospheric pressure and predicts changes in the weather.\nAtmospheric pressure equates to 1.03 kilogram force per square centimetre, though in reality its affected by weather conditions, altitude and temperature.\nThere are may types of Barometers but the simplest and earliest forms are water based.\nThis Instructable will focus on a water based Barometer, although the aneroid variant could also be made.\nOur simple water based Barometer is not an absolute indicator of weather being a gauge but can complement other data such as wind direction and temperature to provide a more informed assessment.\nSupplies\nMason Jar\nClear or translucent plastic tube or Straw\nWater\nFood Colouring or Dye (Optional)\nGrommet and/or Silicone sealer.\nDrill bit (slightly larger then the straw to enable the grommet to be fitted and create a snug fit when the straw is inserted.).\nShort ruler.\nPTFE tape\nStep 1: Methodology\nHow does the Barometer work.\nIt works on the principle of pressure differential.\nThe difference between the air pressure in the upper part of the jar compared to the atmospheric pressure pushing down on the exposed end of the straw. Hence the reason for leaving the end of the straw open.\nAs the atmospheric pressure increases a force is exerted on the end of the straw which pushes the water this then applies pressure inside the jar trying to compress the air in the upper part of the jar.\nAs the atmospheric pressure decreases the force exerted on the end of the straw reduces, the opposing force from inside the upper part of the jar pushes against the water and the level rises.\nThese changes in atmospheric pressure coincide with the weather conditions, higher pressure for more favourable weather and lower pressure for more inclement weather.\nTherefore by monitoring the level of the water in the straw we can get a determination of the atmospheric pressure and from this the weather.\nStep 2: Preparation\nTake the Mason Jar and remove the lid, setting the jar aside for the time being.\nSome Mason jars come pre prepared with hole in the centre of the lid and a straw and this will make the preparation a little easier.\nIf this is not the case then a hole will have to be drilled in the centre of the lid.\nThe hole in the lid should be slightly larger than the straw to accommodate a grommet and once the straw is fitted in the grommet it should form a air tight seal when the lid is screwed onto the jar.\nThe straw should be a tight fit and not too easy to slide into the grommet, if it slides in too easily air will escape and the Barometer will not work.\nIf the straw is too loose in the grommet get a smaller bore grommet, or a wider straw.\nAdditionally, silicone seal can be applied around the grommet and straw to seal any gaps but only after the height of the straw has been adjusted so that its bottom is one 1/4 of the height of the jar from the bottom.\nA thin line of Silicone seal may also be required around the rim of the jar to aid sealing or PTFE tape can be wrapped around the the rim too.\nIf using Silicone seal ensure it is fully cured before further assembly.\nStep 3: Testing\nOnce the assembly is complete the jar should be tested to ensure there are no leaks around the seals for either water or air.\nSimple tests.\n1:Dry test.\nWith the lid and straw assembly firmly in place, suck on the straw after some initial removal of air there should be resistance to any further air removal unless there are any gaps.\nAny gaps should be sealed with further PTFE tape, silicone sealer or a gasket.", "33" ], [ "Balance Bird\nIntroduction: Balance Bird\nBalance and centre or gravity (COG), go hand in hand.\nThe centre of gravity is the point that an object will balance if supported at that point.\nHowever, the centre of gravity is not specifically fixed at a point as it depends upon the distribution of weight about the object in question.\nTaking a <PERSON> as an example.\nIt balances at a point equidistant from each end unless the weight on each end is different.\nBut if we could move the balance point with the dissimilar weighted ends we could yet again balance the see saw.\nReal world <PERSON>'s don't allow you to move the balance point which is why the lighter of two friend tends to be stranded in mid air requiring additional friends to try and add more weight at the lighter end or requiring the heavier individual to move closer to the centre in an attempt to regain balance.\nThis is the same principle of a balance scale were an unknown weight is placed on one side and a variety of known weights are placed on the other side until balance is achieved.\nUsing a STEAM approach and very few materials you can get an insight into COG in a creative format with the Balance Bird.\nScience - Any system of knowledge that is concerned with the physical world and its phenomena and that entails unbiased observations and systematic experimentation.\nTechnology - Methods, systems, and devices which are the result of scientific knowledge being used for practical purposes.\nEngineering - Scientific principles to design and build machines, structures, and other items.\nArts - The expression or application of human creative skill and imagination,\nMathematics - The abstract science of number, quantity, and space,\nCalculating Centre of Gravity.\nCOG = (w1d1+w2d2+w3d3)/(w1+w2+w3)\nw1 = weight of see saw, d1 = balance point from reference end.\nw2 - weight of individual2, d2 = distance from reference end.\nw3 = weight of individual2, d3 = distance from reference end.\nreference end = point were distance measurements are referenced.\nSupplies\nA5 sheet of card\nWhite/Blue Tack, Playdoh, Plasticine or similar.\nScissors or Modelling Knife\nPencil, Pen or Marker.\nStep 1: Creation\nPaper may not appear very technical but is the product of technical processes.\nI created the basic artistic rendition of a bird form (coloured blue), and printed it out.\nA PDF version of the bird form is included which you can print out to use as a template.\nThis was used as a template by placing it over a piece of card, taping one edge to stop it moving and then using a modelling knife* to cut around the template and through to the card beneath.\n*Scissors may also be used as an alternative for cutting.\nCard ls a much more suitable medium as we will need a little rigidity in the form for it to function as required.\nThe centre of gravity of the bird is ~37mm from the beak & the distance from the beak to the wing tips is ~27mm.\nWidth 13cm, length 11cm.\nTherefore, to balance the bird on the beak requires moving the COG forward and similar to a Seesaw with individuals of dissimilar weight we have to add, remove or reposition the weight.\nAs by design we will be moving the COG to the beak we will need to add weight to the wing tips as the distance from the beak to the wing tip is fixed.\nCarefully cut out the bird from the card with a suitable cutting implement.\nStep 2: Art\nHaving cut out the form in the card.\nNow is it opportunity to add some customisation, shading, colour or any other highlights.\nStep 3: Balance\nUsing some tack, create two pea size balls, each weighing ~1g.\nIt only requires a small weight to balance the bird.\nOne ball is then attached to the outer edge of each wing approximately 1cm from the wing tip.\nThe aim is to be able to balance the bird by its beak while the bird balances almost horizontally,\nToo much weight and the tail will point up as in a dive, either reduce the size of the balls or move then a little further back along the wing.\nToo little weight and the tail will point down, either increase the size of the balls or move them closer to the wing tip.\nThe two pea sized balls do not have to be exactly the same weight, some variation can be tolerated which will be evident in a tilt. This will only really be an issue if the bird topples over at the slightest touch.\nSimilar adjustments will be required based on the rigidity of the card.", "717" ], [ "Cardboard Racer\nIntroduction: Cardboard Racer\nThis project will describe the process of making a functional cardboard racing car that is powered by an elastic band and with it how STEM (STEAM), [not forgetting the Arts]; can be applied.\nScience will explore Newtons 3 laws of motions.\nTechnology - Practical application of the Science using the car to perform experiments.\nEngineering - Design and building the car.\nArts - Creative expression to customise and individualise the car by modifying it visually whilst maintaining functionality.\nMaths - Calculation used to generate numerical data for analysis.\nSupplies\nCorrugated Card Board (370 x 230 x 4 mm) * 3\nScissors\nCutting Blade\nClear Adhesive Tape\nGlue\nRuler\nPencil or Pen\nElastic Bands * 5\nCloths Pegs as required.\nBamboo Skewers * 2 (160 mm min)\nM4/10mm screw * 2\nM4/20mm threaded standoff\nM4/20mm screw\nM4 washers * 6\n4 mm drill bit\nBradawl\nStep 1: Newtons 3 Laws of Motion\nWhat are Newtons 3 law of Motion.\n1: An object at rest or in motion will continue to do so unless acted upon by an external force.\nThe car continues in motion once the initial force is applied but will eventually come to a stop as a result of frictional forces. Frictional forces can be significantly reduced by the use of bearings and rolling on a hard surface.\n2: When a force acts on an object, it will cause the object to accelerate. The larger the mass of the object, the greater the force needed to cause it to accelerate.", "668" ], [ "Therefore, force = mass x acceleration.\nThe mass is constant but we can change the force to cause greater acceleration.\n3: For every action, there is an equal and opposite reaction.\nThe more you pull the elastic the more force it generates. The applied force is stored as potential energy and is released as kinetic energy with an equal and opposing force.\nStep 2: Experimentation\nNewtons 2nd law states that Force = mass x acceleration\nThe mass of the car of 0.115kg\nIf it accelerates at 1m/s then the force required is 0.115 * 1 = 0.115 N (assuming no losses in the system)\nm/s * 2.237 = mph.\nGreatest acceleration will occur upon release and thereafter reduce due to external forces.\nIf you time the car over a fixed distance you will get an estimation of speed.\nFor acceleration (1m/s), mass (0.115kg), and the measured displacement of the elastic (18cm).\nElastic Potential Energy (Joules) = 1/2 * Force (N/m) * Elastic displacement^2 (m)\nThe Force is the spring constant = F/dX = 0.639N/0.18 = 3.55N/m\nEPE (Joules) = 1/2 * (3.55N/m * (0.18m^2)) = 0.0575J\nVelocity = sqrt((2*EPE)/kg) =sqrt((2*0.0575)/0.115) = 1 m/s\nMore force is required to overcome frictional losses & elastic efficiency in the system 0.639N versus 0.115N.\nFurther experiments looking at the effects on distance and speed can be conducted.\n1: With stronger and weaker elastics. (greater or weaker force).\n2: For variation in mass..\n3: On hard floors (wood/cushion floor) compared to carpet.\n4: The ratio of elastic stretch.\nReview the data using Excel with charts to visualise the results pictorially and numerically.\nStep 3: Main Body - Part 1\nThis is the body and chassis of the car all in one..\nIts designed for rigidity in the 3d form with minimal pieces.\nOrientate the piece of card (370 x 230 mm), with the long edge horizontally.\nWith the pencil and ruler, proceed to mark the card as per the diagram.\nOnce the card has been marked, proceed to cut the card with a sharp blade using the ruler as a guide\nFolds are marked with dotted lines\nHoles are marked with a cross.\nStep 4: Main Body - Part 2\nOnce the pattern for the car has been cut out folds are required to give it shape and strength.\nAlign the centre line on the card with the edge of a table or box and carefully apply pressure close to the line on the card overhanging the edge of the table/box, pushing the card down to form an angle of ~60 degrees.\nProceed to bend the two short tabs inwards to an angle of ~90 degrees.", "343" ], [ "Hidden Power\nIntroduction: Hidden Power\nPower may reside in a secret and therefore you may wish to keep it in a safe place and what better than a place of power storage, a battery.\nThis project will describe the process of converting a battery into a secret storage compartment with the added bonus that it can be inserted into a multi cell battery pack which will still function although with a reduced voltage.\nChoose wisely an application that is not voltage critical and no one will be the wiser unless they dismantel the battery pack or measure the voltages.\nSupplies\nMaterials\n3D printer\nPLA+ filament (Black)\n22 SWG (~0.711 mm), tinned copper wire\nBattery (AA type)\nMulti purpose glue\nBlack Paint or Black marker and clear lacquer/paint\nEpoxy filler\nAdhesive Tape\nTools\nCura or similar splicer\nGrinder\nDrill bits 1 mm and 8 mm to 12 mm\nHand or low speed drill\nPliers\nCutters\nSoldering Iron\nSolder\nRound profile needle file\nFlat profile needle file\nSanding paper\nWire wool\nScalpel\nProtective Glove\nEye Protection\nStep 1: Preparation\nObtain an exhausted battery, in this case an AA type alkaline. (Other battery types could be used.)\nIf your unsure whether is exhausted, ideally test it under load to determine its condition.\nFor example it may not power your torch but has no trouble powering a TV remote.\nIn the absence of specific test equipment to verify its condition when its no longer capable of powering a Joule Thief or similar low power circuit we can consider it exhuasted.\nWe want an exhausted battery in order to prevent the occurance of a short circuit resulting in damage to the blade from an electrical discharge when the blade contacts the central negative pin and the positive outer case. Even these small batteries are capable of a large current of several amperes which can create a lot of heat.\nBetter still use a grinding wheel which is none conducted and exposes the end rather than cutting into the battery.\nFurther details for the type of battery used in this project can be found in the attached document.\n(No affiliation or connection with the manufacturer of the product in this project, details provided for information only. Check with the manufacturer for the latest updates.)\nStep 2: Removing the End Cap\nWith a scalpel carefully cut off the plastic cover that curls around the edge of the battery.\nThis will expose the edge of the end cap that is spot welded on the end.\nWith a flat blade screwdriver slip this under the edge of the end cap and carefully pry it off.\nIn the process the end cap may bend a little but if not too extremenly bent can be flatterned back into shape.\nThis will expose the vent and insulator ring.\nNow with these removed the end can be ground off.\nStep 3: Grinding\nWearing suitable gloves, eye protection and any other relavant precautions related to the equipment to be used and the process to be carried out.\nCarefully proceed to grind off the negative end of the battery.\nYou will need to remove ~2 mm of the main body to expose the inner construction.\nThe central ring is the anode pin.\nThe white ring is the anode element.\nThe dark ring is the cathode element.\nThe next stage is to remove these elements from the body.\nStep 4: Active Elements Removal\nWearing suitable gloves and eye protection.\nConsult local regulations for the disposal of batteries to be used.\nWrap the battery with a cloth, bubble wrap, antislip material, cork wrap or other suitable material to protect the battery from being crushed when held in the vice or clamp and to prevent it slipping and marking the external surface.\nFirst remove the anode pin with a cocktail stick, a pair of pliers or tweezers which should just slide out.\nNext with a hand drill or electric drill on a slow speed, starting with an 8 mm drill bit remove the white anode paste.\nThe white paste is very soft and will come out easily.\nNext proceed with a 9 mm drill bit to remove the dark brown cathode material, this is much more dense than the white paste and a little more difficult to remove.\nProgressively, increase the drill bit to 10 mm, 11 mm and finally 12 mm which will remove all but a thin layer at the circumference of the cylinder.\nThis thin layer can be removed with flat blade screwdriver and/or scalpel blade.\nThe edges of the cylinder will be sharp as a result of the grinding process and will need to be smoothed with sanding paper or a round profile file.\nApplication of wire wool wrapped around a stick and pushed in the cavity should remove any remaining active material adhering to the insides.", "713" ], [ "Orbital Sound 2\nIntroduction: Orbital Sound 2\nHaving created a previous project called Orbital Sound, the thought came to mind as to whether I could bring it more up to date and include lighting in addition to sound. This would entail electronics and some form of sensor and control.\nThe solution presented itself in the form of a Circuit Playground* microcontroller.\nThis ticked a number of boxes for preinstalled elements, sounder, Neopixels (arranged in a circular pattern), and accelerometer with a small footprint and bolt compatible electrical connections which would come in handy as part of the assembly.", "1003" ], [ "Battery operation also being a bonus.\nThe original version was a fixed form whereas this updated version would enable different sounds and lighting schemes to be employed enabling many variations.\nAll this would be encapsulated within a 3D printed body.\n*The author has no affilation with the CPE/CPB, its creators, manufacturers or suppliers.\nSupplies\nCircuit Playground Bluefruit\nBattery LiPo 3.7V/500mA\nMakeCode Maker\nFilament PETG Transparent/Clear - Main Body\nFilament PETG Transluscent Green - Cord Fixtures\nSlicer Cura or similar application\nBolts M2.5/30mm + nuts - Qty 4\nParacord 140cm length, 1.18mm diameter\nNo affiliation to any of the suppliers used in this project, feel free to use your preferred suppliers and substitute the elements were appropriate to your own preference or subject to supply.\nTools\n3D Printer\nCutters\nScrewdriver (to suit bolt head pattern)\nSoldering iron/Hot plate\nSanding Paper\nNeedle Files\n3mm Drill Bit\nDrill\nKnow your tools and follow the recommended operational procedures and be sure to wear the appropriate PPE.\nStep 1: Design\nThe spinner was designed using BlocksCAD as a 4 part assembly.\nThe aim being to keep the size similar to the original Orbital Sound for stability and ease of use.\nThe body consisting of 2 parts, housing the battery in one half and the microcontroller in the other half.\nLight transmissible filament is used to enable the Neopixel lighting effects to be seen.\nOpenings are placed to enable access to the USB and battery connectors.\nThis means that coding updates and testing via USB and battery charging can be applied without dismantling.\nThe reset and buttons A & B are accessible.\nAdditionally, holes in the body align with the bolt through connection points on the microcontroller which are also utilised with bolts to clamp the halves together. The two halves fit together forming a cylindrical encapsulation.\nThe cord supports consisting of 2 identical elements which fit on the outer side of each body half.\nThese are separate elements due to the inability to loop a single cord through the central body of the spinner and as such needs to be robust to withstand the pulling forces applied during normal use.\nThe cord supports also contain bolt alignment holes, enabling the body and cord supports to be clamped together.\nFour bolts which pass through both the supports and body are used to clamp everything together.\nStep 2: Slicing\nCura was used for the slicing process.\nFor maximum strength the Infill was set to 100% for all elements.\nBase adhesion: Brim\nNo supports are required.\nThe total number of elements consisting of a battery compartment, microcontroller compartment, two buttons and two cord supports.\nSubject to the size of your printer bed and any colour options, elements can be grouped togther to reduce print runs.\nTotal print time: 12 hrs 30 mins (In my experience Cura over estimates the print time, therefore consider this worst case)\nStep 3: Post Processing\nPost processing may be required subject to the quality of the printing.\nRemove any rough or sharp edges with sanding paper or a file from the outer edge of the body halves.\nStringers may exist in the holes which can be cleared out with a drill bit or round needle file.\nEnsure the domed holes in the cord support are clear and smooth to reduce the likelyhood of cord fraying due to rough surfaces.\nThe button extenders may require a little sanding on the base to adjust the height to ensure the CPB buttons are not depressed when the two halves of the main body are clamped together.\nStep 4: Attach Cords\nUsing a 70cm length of 1.18mm cord per side.\nHaving tried a number of different types of cord/ string etc. twisted packing string starts to loose its twist and flat film raffia starts to fray, paracord has shown better long term performance in use.\nAdditionally of the varieties tested thinner cord (allowing more twists), performed better than thicker cord.", "16" ], [ "LED Kaleidoscope\nIntroduction: LED Kaleidoscope\nYour typical Kaleidoscope is an optical instrument with two or more reflecting surfaces tilted to each other in an angle, so that objects on one end of the mirrors are seen as a regular symmetrical pattern. The reflectors are usually enclosed in a tube, containing on one end loose coloured pieces of glass/plastic or other combinations of transparent and opaque materials to be viewed. Rotation causes materials to move creating random patterns.\nThis version closely follows the general design however, were your typical Kaleidoscope uses physical elements that move under the influence of movement this version used LED's to display everchanging random patterns.\nThe patterns are displayed on a Zip tile for Microbit, this contains 64 LED's in an 8 x 8 matrix which are controlled by the Microbit.\nSupplies\nMicroBit\nZIP Tile LED Display\nPlastic Mirror 212mm long x 40mm wide - Qty 3\nBlocksCAD\n10mm M3 X M3 Hex standoff threaded hole & screw - Qty 6\n15mm M3 X M3 Hex standoff threaded hole - Qty 3\n3mm x185mm rod - Qty 3\nM3 X 10mm countersink screw - Qty 3\nMasking tape.\n2mm drill bit.\nPliers.\nM3 box spanner.\nScissors.\nStep 1: Aperture Ring and Carrier Design\nThese elements are designed using BlocksCAD and are 3D printed.\nThe carrier supports the Zip tile and Microbit in place and into this is inserted the aperture ring.\nThe aperture ring is a press fit into the carrier and once pressed into the carrier rotates freely by turning with the knurled edge.\nThe three mirrors in the form of a Triangular prism sit in the recess in the Aperture ring.\nWith these elements in place the image is viewed between the mirrors and rotation of the aperture ring allows the display of the existing pattern to the varied.\nStep 2: Support and Eyepiece\nThese elements are designed using BlocksCAD and are 3D printed.\nThe Supports slide over the reflectors and are spaced at intervals and in conjunction with the rods form the body of the kaleidoscope.\nThe Eyepiece fits over the end and caps off the body.\nStep 3: 3D Printed Hardware\n3D printed elements consist of the Supports and Eyepiece additional to this the Aperture ring and Carrier which are printed as two separate elements that are then clipped together.\nStep 4: Microbit and ZipTile Assembly\nThe Zip tile is attached to the Mircobit by five M3 bolts and cylindrical spacers.\nBoth elements are orientated with the LED's facing upwards and the Microbit visible enabling easy operation of the A button.\nHowever, the Microbit can be mounted in invisible mode on the back reducing the profile if required.\nDetails for the Zip tile and assembly options are given at the following link:\nhttps://resources.kitronik.co.uk/pdf/5645-zip-tile...\nStep 5: Display Assembly\nThe Display assembly consists of the Zip tile, Microbit, Aperture Ring and Carrier.\nThe Zip tile + Microbit are slid into the underside of the carrier and held in place by the close tolerance of the design.\nThe carrier supports the Zip tile and the Aperture sits central to the Zip tile.\nStep 6: Reflectors\nThe reflectors or made up of three rectangular mirrors formed into a triangular hollow prism and held together with tape.\nThe mirrors are made of plastic making them easy to cut whilst at the same time being less fragile than glass.\nThese were cut from a single sheet with a portable table bench saw although a hand saw could be used if clamped along the full length of the edge to be cut to prevent breakage or movement resulting in scratches or an uneven cut.\nThe triangular hollow prism is placed end on to the Aperture within the triangular recess.\nThe ZIP tile mounted at one end is then viewed through the centre of the hollow prism.\nStep 7: Assembling the Body\nThe assembly process is shown in the accompanying images in addition to the following description.\nUsing one of the Supports place it over the Aperture ring and align the centre triangle.\nWith a pen mark the Aperture through the three holes in the Support.\nWith a 2mm drill bit make three holes at the points previously marked, into these holes screw a standoff.\nTake each of the rods and taper each end with a knife/file/pencil sharpener subject to the material.\nIf metal rods are used then threads will need to be cut on the ends at this point.\nFit three standoffs, one on the end of each rod and screw approximately10mm of the rod into the threaded hole of the standoff.", "134" ], [ "Halloween Condiment Set\nIntroduction: Halloween Condiment Set\nAt Halloween time we display the Pumpkins and with the inner flesh make soup, pies and other food items.\nAs a food item you will invariable add a condiment in the form of salt, pepper or some other savoury or spice.\nIt therefore seemed appropriate to create a Pumpkin themed condiment set for salt and pepper as a minimum.\nThe condiment set was designed using BlocksCAD then 3D printed.\nSupplies\n3D Printer\nFilament (Food Safe) - Orange, Green\nFood Safe Finish\nFlexible Filament (TPU) or Natural/Synthetic Cork\n2 part resin - Black\nBlocksCAD\nCura\nLong nose pliers\nCutters\nStep 1: Design\nEach dispenser will be made up of only three elements spout, container and stopper which can all be 3D printed and requiring no supports, simplifying somewhat post processing.\nThere will be two design variants, one for salt and the other for pepper.\nThese would be differentiated with both a facial and a spout design.\nThe facial designs will be included as part of the container giving the impression of being carved into the outer surface. (The only holes needed are for the spout and stopper). This will enable a resin inlay to be applied to highlight the facial features.\nThe spout would represent the stalk on a real Pumpkin.\nIn addition the bottom would have provision for a stopper.\nThe main facial variations would be with the eyes and the spouts with different hole counts.\nThe main container is based around a miniature Pumpkin variety, tending to have a more flattened top and bottom more reminiscent of a small wheel rather than a ball.\nStep 2: Pumpkin CAD - Part 1\nBlocksCAD only has primitive shapes and as a result we need to create the Pumpkin shape.\nBased on the use of a sphere, this gives both a rounded shape and the ridges in the surface.\nThis is accomplished by an iterative loop which plots the sphere at a different angle around the circumference of a circle from 0 to 360 degrees based on the specified radius.\nA cross section is included to illustrate the position of the spheres and intersection were the ridges are formed.\nHad the code used the polar co-ordinate system the position around the circumference to position the sphere could have been calculated from the radius and angle from the centre of the circle.\nHowever, as the code is using the rectangular (Cartesian), co-ordinate system its required to specify the x and y position.\nWe can relate the x, y position to the position on the circumference of our circle by using Sine and Cosine functions.\nUsing a unit circle with radius of one the Sine and Cosine at each angle is shown, this is multiplied by the radius of our circle to provide our co-ordinates.\nThe number of ridges is related to the size of the sphere and the number of steps around our circle circumference.\nA step angle of 20 degrees (18 sections), was chosen.\nHowever, this part of the process creates a solid Pumpkin which needs now to be hollowed out.\nStep 3: Pumpkin CAD - Part 2\nThe process of hollowing out the Pumpkin requires the use of the difference function which will subtract one object from another.\nThis is accomplished by plotting a smaller version of the original shape inside the original. In this case the radius is 4mm smaller.\nStep 4: Pumpkin CAD - Part 3\nAt this stage the object still appears to be solid.\nIn order to open up the Pumpkin the holes for the spout and the stopper need creating.\nAgain using the difference object a cylinder with radius 10mm and the same height as the sphere is placed in the centre of the Pumpkin object.\nApplying the facial expressions is next.\nStep 5: Pumpkin CAD - Part 4\nThe objects used to create the face are placed in such a way as to leave a depressing but not to create an excessive overhang that would create a void in the outer shell.\nThe nose is a triangle subtracted from the Pumpkin object.\nHowever, the triangle is not a basic shape and is created from a cylinder using the Side transform which is set to 3.\nNext we add the eyes created using the torus object in conjunction with the taper object to elongate the eye for a more sinister look.\nTo add symmetry include the rotate object and apply 180 degree on the X axis of the eye on the left.\nThe mouth is made up of five diamonds (there being no default diamond object this made up of a cylinder applying the Side object which is set to 4), applied in an iterative loop.\nThese facial elements are subtracted using the difference object to create a depression in the Pumpkin surface and coloured blue for contrast.\nThe main pumpkin design process is complete but two are required.", "646" ], [ "Among Us Inspired Automata\nIntroduction: Among Us Inspired Automata\nThis project is a STEM-based activity for high school or college students with prior knowledge of how simple machines function independently. It is also helpful if the student has knowledge of how to use lab equipment found in an engineering design class such as a table saw, laser cutter and drill press. By constructing an automata, students will be able to learn how cams, levers, linkages and the mechanics of movement function together. The completion of this mechanical sculpture will also show how simple machines can come together to create non-motorized movement.\nSTEL. In order to implement this tutorial in a classroom setting, we will be using Standards for Technological and Engineering Literacy to gauge what students should know and be able to do in order to achieve a high level of technological and engineering literacy.\nThe basic structure we will use to measure this is by first establishing the core disciplinary standards which represent all broad areas of technological activity in our world. Then we will show the practices that can not only be applied to the core disciplinary standards and contexts, but these can be applied to many real world situations as well. Finally, we establish contexts that tie back into the core disciplinary standards by representing 8 specific technology content areas.\nCore Disciplinary Standard.", "226" ], [ "The core disciplinary standard that aligns with this activity is Standard 2: Core concepts of Technology and Engineering. We see this standard reflected in the activity as we create a system by using multiple simple machines together to make non motorized movement. This activity is also a process where we use different resources and sequence of steps to produce our final product.\nAs the teacher/professor it is important to use STEL-2H where you identify all of the resources needed to create this automata, including materials, tools, machines, time and knowledge.\nPractices that are used in this activity include systems thinking; as we will be making separate simple machines function together to provide an output of up and down movement.\nMaking and doing; as we will be modeling, building and using scientific principles to create a physical, non motorized product.\nCritical thinking; as students will use their logic, reasoning and prior knowledge of simple machines to generate movement with only the materials provided.\nContext. The context that aligns with this activity is TEC-6: The Built Environment. We see this context reflected in this activity as students will design a wooden structure with components inside of it that also has to maintain its structure as it is interacted with. This is similar to real world structures such as building structures and students will understand that all structures have subsystems that have specific purposes. This activity also helps with spatial relationships, as students have to make sure things are scaled appropriately. Despite primarily being made of wood, students will notice that a different material would function a lot differently.\nSupplies\nFor this activity each student will need\nBass wood sheets\n* Longest sides- 18cm x 10cm (x2) -- 1/8th inch drilled holes 5cm from the bottom\n* Base- 9.9cm x 9.8cm\n* Inner squares- 9.9cm x 9.2cm (x2) -- 0.9cm x 1.2cm cut in the center\n* Front cover- 7cm x 10cm\n* Back cover- 10cm x 10 cm\nBalsa wood\n* Large wheels 4cm in diameter (x2) -- 1/8th inch drilled holes, 1 hole in center, other hole near edge\n* Large wheel 4cm in diameter -- 0.9cm x 1.2cm rectangle in center\n* Small wheel 2.5cm in diameter -- 1/8th inch drilled in center\nAdditional materials + tools\n* Dowel rod- 15cm, 1/8th inch diameter (x2)\n* Flat rod- 12.5cm x 1cm\n* Foam sheet\n* Among us inspired character- 5.7cm x 4.3cm (provided)\n* Wood glue\n* Ruler\n* Drill press or hand drill\n* Table saw\n* Laser cutter\nBased on the materials purchased, three students could do this project for about $30, with majority cost being in buying the wood\nAll dimensions and drawn parts for the automata can be accessed through this google drive link numbered in parts1-11:\nhttps://drive.google.com/drive/folders/1gc9_obpzO7PdRYqbSs5ck8peBmUeyC6T?usp=sharing\nStep 1: Longest Sides\nUsing a drill press or a hand drill, drill the 18cm x 10cm pieces of bass wood with a 1/8th inch drill bit 5cm from the bottom.\nStep1 needed parts and dimensions for automata can be accessed through this google drive link:\nhttps://drive.google.", "668" ] ]

[ 8550, 10124, 4675, 8653, 10201, 11242, 1461, 789, 4036, 9538, 11320, 11406, 8514, 154, 9447, 4445, 11379, 11429, 3611, 3144, 2351, 5494, 7718, 9248, 5067, 9145, 4044, 9254, 2116, 10377, 3574, 2137, 5667, 232, 9448, 2515, 4984, 7536, 5944, 10574, 6988, 6981, 11031, 5989, 62, 10910, 4463, 5834, 1588, 7120, 2076, 9953, 1075, 5814, 6328, 3024, 2732, 3535, 6236, 819, 6092, 8380, 8074, 5033, 3265, 7797, 7116, 8783, 8265, 7895 ]

[ [ "What makes CO2 gas \"sticky\" in pipes?\nThere's some recieved wisdom where i work that when flowing CO2 gas in pipes it acts somewhat \"sticky\" in that it lingers around longer and takes more N2 or air to purge out than, say, Methane or N2.\nUnfortunately no-one here seems to know the physical or chemical basis for this observed result. I do have some quantative data through various flow sensors & IR gas sensors that shows it really does stay around longer than N2 or CH4, so i don't think it's due to bad observation.\nAs you can imagine, googling \"why is CO2 sticky\" is not very helpful.\nIf anyone can explain to me why this happens i'd be very grateful, or even just point me in the right direction to do my own research.\nThanks.\nEDIT: Thanks for your responses so far.\nHere's some more info on our gas system: we buy in our CO2 in large bottles at ~400 psi. We then feed it from outside through a pressure regulator that regulates it down to 2 bar (~29psi) absolute pressure. All the pipes until this point are stainless steel.\nIt's then fed through a proportional valve and the pressure is held at 1030 mBar over a set of flow and gas sensors, then exhausted to atmosphere. The pipes in this section are a mix of Polyurethane tubes, and two proprietary rubber-like materials called Tygon and Viton tubing.", "542" ], [ "These are held together with nylon fittings. All of this is at ambient temperature.\nIn these pipes, only N2, CO2 and CH4 flow.\nHere's some graphs i collected of the system: In this graph, the green & brown lines are each gas being flowed in the system. th two blueish lines are a rough analogue of how much CO2 is detected in the system. As you can see, even after 5 mins of methane and N2 purging, and continuous intermittent N2 purges, CO2 still creeps back into the system when no gas is flowing.\nHere's a Graph of Gas Flow The [Flow In] sensor is just after the 1030 Prop valve, and the [Flow Out] sensor is just before the exhaust. They are both identical wheatstone bridge thermal flow sensors.\nAs you can see, there's a marked increase in flow loss (Flow In/Flow Out) from 2% to about 7% when CO2 is flowing, and some very strange transient spikes when I switch gasses to/from CO2.\nThat's most of the data I've collected. Anecdotally, i've also noticed that the CO2 valve is significantly harder to turn than the N2 or CH4 valves.\nI hope this helps with the problem, and thank you again for your help so far.", "542" ], [ "Designing a pneumatic system for consistent pressure/flow\nFellow engineers, I need your help in improving my design for a pneumatic system for maintaining a constant supply of at least 90 PSI and 20 CFM for a particle analyzer with stringent air requirements. Its expected to draw air every 2 seconds. Here's the breakdown of the components used in the setup (in this order). Picture attached.\nA: Bulk water separator. This should help with removing moisture from the air because our plant air is heavily moisture-laden at times.\nB: Particulate filter: 0.01 micron air filter to ensure clean air, free from particles.\nC: Desiccant air dryer: Heat-less desiccant dryer for dry air. -40 C pressure dew point to ensure that there is no further condensation beyond this point and the air stays dry till it makes its way all the way to the analyzer. The dryer is rated for an inlet flow of 45 SCFM. I up-sized it because this is a heat-less dryer so a certain percentage of the air going in to the dryer will be used to regenerate the desiccants as well.", "842" ], [ "The dryer has an in-built filter that will prevent any of the desiccants from leaving the dryer.\nD: Globe valve: This is to contain the flow rate coming out of the dryer. This was suggested to me by another engineer. Since we are filling up a large tank, the air coming out of the dryer could potentially exceed the rated flow rate of the dryer which could damage the desiccants.\nE & F: Check valve and booster pump in parallel. The booster pump is meant to charge the receiver tank to a pressure of 95 - 100 PSI. The check valve is there to reduce the charge time by allowing air to pass through up to the inlet pressure. This could help take some of the burden off of the booster pump so that the pump only cycles when the tank pressure needs to be raised to setpoint.\nG: Air receiver tank: This will help create a reservoir of air that will ensure that the analyzer never has to wait for air. The tank is rated for 200 PSI but I won't be charging it more than 100 PSI. Still debating if I should go with a smaller tank because 80 gallons is an awful lot of volume for the booster to fill.\nH: Filter: To get rid of any of the remaining particles and oil vapors left in the system.\nI: Pressure regulator: To maintain the desired pressure for the equipment\nJ: Equipment - Particle analyzer.\nAny suggestions on improving this design?", "842" ], [ "how large would the leaks have to be to counteract the positive effects?\nTrying a ballpark estimate ... biogas replaces natural gas. For simplicity let's assume the replacement is 1:1, one mole of methane from biogas* replaces one mole of natural gas. This also means that one mole of biomethane \"saves\" one mole of CO2.\nMethane is about 25 times more intensive in terms of cliamte change than CO2. So if 100/25 = 4% leaks, the positive effect would be offset.\nThe factors influencing gas leakage, from biggest to smallest influence (this is mostly from memory):\n* Retention time of substrate in gas tight system - depending on retention time in the digesters, the digestate could still have 10% or so of it's total biogas potential, when the digestate storage is open and the HRT is short. One of the later iterations of the German rennewable energy laws specifies 150 days retention time in the gas tight system for this reason & I think this is reasonable for many substrates.\n* Leaking foil roofs - foil roofs are common on large tanks, especially the connection foil roof/digester is a common point for leakage. This study found leakage rates from plants between 0 and 20 Nm³/h (median 5-10 Nm³/h), size of plants was not given but probably around 500 Nm³/h biogas production.\n* Methane slip - I don't have numbers to go by, but I think 0.5-1% of gas slip (unburnt gas in the exhaust) in IC motors is common.", "842" ], [ "This regardless of wether you burn natural gas or biogas, AFAIK.\n* Manure storage - some wastes will ferment on their own, esp. manure.\n* Everything else - IMO the art of building gas pipes etc. is pretty well developed, if proper procedures are followed and proper materials used leakages from pipes should be neglible.\nIn summary, the methane loss of biogas plants may well be above the 4% cutoff point I mentioned above, or well below, depending on plant design and quality of building.\nHowever, as you pointed out in comments to your question, you need to also look at what would happen to the feedstock without biogasification. Manure would ferment (but not as completely) in an open pit and emit gasses. Municipal wastes would be either incinerated (likely with additional fuel because of the high moisture content), composted or landfilled (landfilled wastes also ferment and produce biogas, if this goes to the atmosphere, is flared or used productivly depends on the site). I have worked in landfill supervision and design of biogas plants.\nAt this point, I lack good numbers to really compare biogasification to other disposal paths. Having worked in landfill supervision and design of biogas plants, I have more trust in a properly designed biogas plant to keep methane out of the atmosphere than in a typically, well maintained landfill. But I'm sure you can find shoddy biogas plants that leak, for the same amount of input, worse than some landfills!\nLikewise, I'm still looking for hard numbers of fuel usage for incineration of biowastes, so I can't offer a good comparison here.\nSo IMO, while biogas from energy crops is highly questionable, biogasification of wastes is a net benefit if done properly.\n*biogas is anything between 50 and 70% methane, the rest CO2 and traces.", "1022" ], [ "How does the silver nucleate on glass in Tollen's reagent mirroring?\nI'm trying to figure out how exactly does the silver start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how i see the nucleation/growth process of silver on silica:\nNow, as you can see, i didn't draw any chemical bonds. That's because I think that the silver adherence is due to Van Der Waals forces. Am I right to think this? If this is the case, then a place with high permanent polarisation would be better suited for the nucleation of silver.\nNow, let's follow the logic. We have a greater electronegativity difference between O and Si (3.44 - 1.90 = 1.54) than between O and H (3.44 - 2.2 = 1.24).\nFor the upper oxygen, assuming an angle of 109 degrees, you get a total dipole moment of: 2 (1.54) cos(109/2) = 1.79\nFor the lower oxygen with the bonded hydrogen, assuming an angle of 120 degrees , you would get a total dipole moment of: 1.54 + 1.24 = 2.78 (please tell me if i'm wrong to assume a straight line!)\nSo, this would mean that you have a greater accumulation of electrons at the bottom oxygen, which would favor Van Der Waals attraction (Debye interaction, I guess, since you have a permanent dipole and an induced dipole).", "969" ], [ "This, in turn, would mean that it would be a better nucleation site.\nNOW, i like ranting, so i'll go on. If you make a surface treatment using silane groups, I think that you promote the presence of OH groups at your silica surface, although my understanding/knowledge is hazy at this point. I do know that it makes better silver mirroring though. I made another drawing:\nFollowing my logic, this one is wrong in many way. First of all, i drew angles on the Si - O - H bonds, which I didn't draw on my first pictures. Second, the silver is not even near the oxygen atoms, which are supposed to be the nucleation points, according to me.\nI'm confused, could you please point out to me where i'm right and wrong in my logic/knowledge? Mainly: - Is there a bond forming between the silica surface and the silver or is it <PERSON> Der Waals (<PERSON>) attraction only? - Is my depiction of nucleation & growth correct (the first two pictures)? - Did I make the electronegativity maths correctly? - Is my logic of \" higher total electronegativity difference, hence better nucleation site\" correct? (assuming i'm right about the <PERSON> thing) - Is my depiction of silanisation correct? - Am I right to say that the higher presence of surface OH groups by silanisation mean better nucleation - If this is the case, could I do the same thing using a strong acid on my glass surface?\nThank you very much!", "979" ], [ "How do I calculate the Sieverts/hour that a gamma meter would see at x distance from a radioactive sample?\nI'm working on a little proof of concept program where I want to input some weight of a radioactive element, and then calculate what a meter would read at different distances. Ultimately I hope to also add some shielding to the calculation like a concrete wall or something. I've been reading and trying to learn how this calculation would work but I don't think I have it yet.\nSo far I understand I can calculate the activity if I understand the number of nuclei and the half life. As an example I take a 1gram sample of Cesium 137 with a half life of 2.6 min.\nCesium has an atomic weight of 136.9amu = 2.2733×10^-22 grams. A one gram sample should then have 4.398E21 nuclei in it. Although I also read that the gamma photon that comes from Cesium decay comes when it decays to boron 137 and it only does that 85% of the time.", "617" ], [ "So maybe I should reduce this by 15%?\nAnother formula tells me activity is equal to the decay constant times the number of nuclei:\nlambda = ln(2)/half-life in seconds lambda = <PHONE_NUMBER> seconds lambda = 0.0044423\nA(t) = lambda * Nt A(t) = 0.0044423 * 4.398E21 A(t) = 1.9537E19 Bq\nAssuming my math is okay 1.9537E19 Bq is how radioactive my sample is. When I tried to search for dose at distance I just found a lot of formulas explaining the inverse square law. As in if you know how the dose at 1m here's how to calculate it at 4m. But I found one formula that said it calculated the dose from activity and range.\nH = 1.5E-13 * A * E * n/r^2\nWhere: H = dose in Sievert/min A = activity E = photon energy 0.6617MeV for the Barium 137? n = # emitted per disintegration. 1 I think for Barium 137 r = distance in meters say 2 meters for this example\nThat would be: H = 1.5E-13 * 1.9537E19Bq * 0.6617E6 * 1/(2^2) H = 484786233750 Sv/hr\nThis seems pretty high to me but I don't know for sure. Am I on the right track here or way off base? Have I grossly over estimated how large a real sample of Cesium 137 would be?\nThank you", "565" ], [ "Short answer:\nI suspect that so long as your pump is a positive displacement pump (ex: the \"vibratory pump\" or \"rotary vane pump\" as described in this webpage about espresso pumps) and is sized to output the flowrate you desire, then you only need a discharge valve or an appropriately designed flow restriction device (ex: a restriction orifice or your \"pressurized filter basket\").\nIf you need to reduce flowrate of a fixed-speed positive displacement pump yet maintain a controlled pressure, read on about installing a recycle line.\nLong answer:\nControlling mass flowrate and pressure through a pressure vessel (an espresso machine) is possible. I'm not an expert in espresso machines but I am somewhat familiar with the equipment needed to carry out the chemical engineering unit processes of solid-liquid extraction (ex: making espresso); I'm used to larger machinery.\nPump\nYou need a pump that can is capable of providing more than the maximum desired flowrate at more than the maximum desired pressure. A quick search for espresso pumps brings up this page about rotary and piston pumps, both positive displacement types. These pumps tend to output constant flowrate no matter the output pressure (they may still output less due to seal leakage and power limits of the motor).\nIf your pump isn't a positive displacement type, there are engineering methods that use \"pump curves\" as <PERSON> described to take into account quirks about other pump types (ex: centrifugal). However, no matter the type of pump used, as long as sufficient pressure and flowrate capacity in the pump is available, I know of three methods for controlling the pressure and flowrate through the system:\n1. Speed control\n2. Discharge control\n3. Recycle control\nYou will need at least two of the three.\n1. Speed control\n\"Variable Frequency Drive\" or, VFD, is a way to adjust the speed of the pump's rotating elements. Slower generally means less flow rate and pressure.\nFor your application, I imagine this would be an electronic module that adjusts the frequency and voltage of the alternating current electricity that powers your device. In the U.S. it is probably a frequency of 60 Hertz (Hz) at 120 volts of alternating current (VAC). I am not finding many hits on searches for variable speed espresso pumps so perhaps this type of control isn't popular.", "568" ], [ "This doesn't surprise me since adjusting frequency of power requires complex electronics.\nUsing a VFD is like adjusting your pump size without having to buy a new pump.\n2. Discharge control\nThis type of control involves restricting flow leaving the pressure vessel with an adjustable valve. Generally, when the valve is more closed, an increase in upstream pressure and reduction in flowrate through the system results.\nThe \"pressurized filter basket\" you mentioned in a comment on another answer sounds like it may fulfill the role of a discharge control. However you decide to restrict discharge flow, the discharge valve position (or orifice sizes of the basket?) will have to be adjusted in tandem with the other control method you select (Speed control or Recycle control) in order to achieve a desired pressure and flow through the pressure vessel.\n3. Recycle control\nThis method of control involves sending a portion of the flow leaving the pump or pressure vessel back into the inlet of the pump.\nIn your application, this may be achieved by installing two tees:\n1. A tee on the high pressure piping at the vessel or pump outlet\n2. A tee on the low pressure piping at the pump inlet.\nThen, you connect the two tees with a length of pipe containing a flow-restricting valve; this is a \"recycle line\". When the pump runs, some amount of fluid continuously recirculates if the recycle line valve is open. As the valve closes less fluid is permitted to recycle and the flow of fluid out of the system increases (provided the discharge control valve (if present) is somewhat open).\nRecycling fluid wastes some energy since fluid is pressurized by the pump and then depressurized at the recycle valve without leaving the system. The wasted energy heats the fluid somewhat. Recycling fluid might be desired if a limited supply of water is available or more extensive leaching of the coffee grounds bed is desired.\nMaintaining pressure and flowrate\nAs I mentioned before, if you have a pump that can output more than the desired flowrate at more than the desired pressure, then two of the three control methods will be necessary to maintain pressure and flowrate within the pressure vessel. This is the result of what in chemical engineering is known as a \"degrees of freedom analysis\". You will notice this phenomenon if you set up your system in a process simulator (ex: DWSIM (FOSS), VMGSIM (proprietary)) and fix pressure and flowrate of the pressure vessel.", "568" ], [ "Current atmospheric O2 levels are about 21%, though the Oxygen compensation point dictated by C3 plants who produce our O2 limits it to about 23% at current CO2 levels. Higher CO2 levels permits increased photosynthesis rates and a correspondingly higher atmospheric O2% level.\n220 ppm CO2 has a upper O2 limit of 23%O2. 350 ppm CO2 has a upper O2 limit of 27%O2. 700 ppm CO2 has a upper O2 limit of 35%O2.\nThese limits are \"theoretical max\" which you'll never reach due to O2 consumption from both organic metabolism, and from inorganic O2 fixation (I.e. rust and other metal oxidation). Once you hit the O2 compensation point, plants stop growing... they reach a point where the O2 levels provide a compensating force on enzymes that halt production of Rubisco.\nWhats this mean in modern terms? well... we have increased volcanic activity, massive forest burning in Thialand and Brazil which has driven up CO2 levels since 1800. The increase CO2 raises the maximum O2 concentration and hense the plant-based biolevels possible (ie. more crops, faster growth of plants/food).\nglobal O2 levels move VERY slowly, though its worth noting that past CO2 levels around 1500 ppm correlated to about 35%O2, so even at high compensation points (max levels) they never reached very high.\nHumans can supposedly breath 50%O2 all day long without issues, and Scuba Divers like myself can get Nitrox-certifications to use 40% Nitrox (40% O2 with 60% N2) for shallow dives (the higher O2%, reduces the %N2 in the mix to slow nitrogen gas uptake in the blood... basically we use it to do longer dives without having to decompress).\nYour question about 30% is interesting. 1) it would give endurance athletes a higher \"effective\" VO2 Max and would theoretically allow marathon runners to run at slightly higher speeds/effort while staying in the aerobic-exercise zone. This doesn't mean they could go farther, total energy is based on calories available... only that they could burn the same energy faster.", "279" ], [ ";)\n2) Sprinters and other anaerobic activities would be unaffected... except for recovery rates! Hockey players, basketball, soccer, etc where stop and go windsprints are common could see reduced recovery times (i.e. hockey players could go back on the ice after shorter breaks without lactic acid building up). Even in todays pro sports you see this on football sidelines and hockey benches where winded all-stars will dawn a O2 mask to reduce lactic acid. So you could sprint more often, but not necessarily any faster.\n3) Insects wouldn't be bigger. The giant insects in eras past were originally thought to be from O2 absorption, but studies in hyperbaric chambers have shown that O2 absorption rates are not limiting factors. Most scientists attribute ancient giant inserts to a lack of predators in that era, and an abundance of food. They simply lived long and ate well (in addition to theories about indeterminate growth and genetic differences in ancestors).\n4) Fire hazards may be an issue, though an increased oxygenation rate of metals and spoiling of foods would be the most common issue for sure.\n5) Lastly, its worth noting that CO2 levels in your blood are what trigger your brain to breath. The peripheral chemoreceptors in you carotid arteries will trigger breaths when CO2 concentration rises to 40mmHg. The CO2 levels in your blood vary between breaths from 35 to about 45mmHg are generated by metabolic means. So will increasing atmospheric CO2 levels affect your ability to breath? Nope. 40mmHg which is found in your blood and lungs alveolar space is 53000 ppm... which is why it diffuses out of your blood and into the lung space (since air is only ~400ppm). Increased CO2 and O2 levels shouldn't affect your ability to trigger breathing unconsciously. ;)", "279" ], [ "It's important for mechanical engineering students to get what we old timers describe as an “intuitive feel” for their subject. Luckily such is possible in this field, but not always in other fields, such as in Quantum Mechanics. Here's my suggestion for such an intuitive feel.\nMany of the answers give “correct” suggestions, but I don't see in any of them a way presented for the student to understand the physics that occurs as steam is giving up its internal energy in exchange for useful work.\nYes, it's due to the fact that latent heat is involved and that latent heat is orders of magnitude larger than sensible heat, or potential energy of compression, as you would have with using air as the working fluid. With compression of air, there's the added difficulty to hold onto all the energy put into compression. Compression increases the temperature of the air, and if the air storage tank isn't insulated, you will lose much of the compression energy in the form of heat to the environment.\nHere's the crux. Steam is usually introduced into piston engines and turbomachinery in the supersaturated state. In this state, it contains energy in a way similar to compressed air: there's no phase change. Thus, in the first moments in its travel through the machinery, it gives up its enthalpy (the best measure of energy transferred) just like compressed air does, until it begins to condense, which will occur when its pressure and temperature allow it, as it flows through its change of state within the machinery. With condensation, latent energy is released, and that “extra” energy can be intuitively visualized as a way for the liquid-to-vapor transition to add to its volume, with a tendency to increase its pressure above the pressure that it would experience without the phase change. As the steam flow continues down to lower pressures, more latent heat is given up, effectively keeping it's pressure at higher levels than it would be without the change of phase.\nThere's a very complicated relationship among the actual pressure experienced, the actual temperature experienced, and the amount of liquid water formed. There can be no latent energy release without the formation of liquid water, and the liquid water can cause damage to turbomachinery.", "568" ], [ "Thus the process is controlled and by the time the steam exits the machine, very little actual liquid water is present. It's a bit magical.\nAs some others point out here, that exiting steam is introduced to the condenser, which causes a partial vacuum in the condenser, increasing the overall pressure difference across the machine. When the steam enters the condenser, it's “quality” is relatively low. Quality is the mass fraction of vapor to liquid in a saturated fluid. Zero quality is all liquid. 100% quality is all vapor. And also as pointed out, the liquid water leaving the condenser requires much less energy to pump up to the boiler pressure, than if it were in gaseous form. That's because water is nearly incompressible, and work done is force times distance. With very little distance, there's little work done.\nFrom this view, one can see very easily that latent heat is a very important aspect to the use of steam as a working fluid. It takes much energy to vaporize liquid, but you get much of that energy back in the expansion process. Latent heat can be viewed as a large bucket, enabling you to carry a large amount of energy to the workings of the machine. With air, there's no such mechanism and you can't carry nearly as much energy to the machine.", "479" ] ]

[ 11312, 4088, 8591, 8217, 2345, 9472, 9134, 106, 9060, 9670, 2455, 1952, 1088, 10740, 5383, 3581, 2622, 7959, 5864, 5023, 3136, 7352, 1445, 3781, 10341, 3779, 1408, 8104, 4459, 9981, 6334, 1213, 3080, 4389, 337, 10494, 3335, 8910, 9577, 7130, 605, 10184, 10490, 756, 7110, 214, 785, 11379, 5174, 7154, 5702, 6349, 10198, 7009, 1765, 8957, 6907, 11054, 1112, 8845, 7515, 3380, 1649, 2355, 2828, 6189, 9394, 2547, 2305, 3744 ]

[ [ "Can't move my dog to a new vet.\nPrevious owner moved to Australia 16 months ago. Original plan was I'd foster care until he could arrange transfer.\nAfter a while of keeping her we both decided it wasnt fair on the dog to put her through the stress of travel and she'd be better staying with me. All agreed, all fine.\nTrouble is he is awful at communications.", "1011" ], [ "I've transferred the microchip on the basis that he had 30 days to respond and after that it just automatically transfers.\nHer current vet is Vets4Pets, miles from me. I keep ringing asking them to change the ownership to me, and they can't until he replies to an email they sent. That was 2 months ago and he hasn't replied.\nI'm stuck because I don't know what else I can do - I ask him to reply to the email and he never does.", "498" ], [ "Need help with some diagnosis\nHello. I am in the UK so refer to my times as BST(British Summer Time)\nToday, we had to do the hardest thing and put one of our dogs to sleep. This was at 7:30pm. However, I'm needing some help or some advice as to why she got so sick. So in the morning. She was absolutely fine, to the point where she was her normal self and playful as ever.\nYet at around 3pm. She started to be sick again and again.", "664" ], [ "Right after one another. The first time was her breakfast and from then on. It was like.. flem. So from then onwards, I also noticed her breathing was getting shallower/struggling to breathe. So taking her to the vets and she didn't improve at all. In fact she got worse and to the point where she was declared critically ill.\nSo I'm looking for advice as to what this possibly could've been as the vets weren't able to disgnose it. Especially since she was fine in the morning and just instantly turned from 3pm onwards to us having to decide to let her cross the rainbow bridge.\nCould it be poison or something? As the back gate to our garden was open 2 days ago super randomly as nobody goes in and out it unless doing some gardening etc.\nVery heartbroken at the sudden loss.\nShe was a 9 year old Yorkshire Terrier.", "664" ], [ "Adopted a cat the other day. I might be regretting it.\nHi all.\nI want to start off saying the cat is lovely, beautiful and adorable. Nothing wrong with her.\nI adopted a cat Saturday, and all Saturday night she cuddled up with me. I woke up Sunday morning congested and sneezing a LOT. I assume I could be allergic to her, which hurts.\nShe is currently stuck in my room since we have another cat and a dog.", "679" ], [ "We introduced her to the dog (the dog LOVED her) but the cat really, really did not like the dog at all and get incredibly skittish afterwards.\nI feel absolutely horrible. Legit tearing up at the thought of it. She's 4 and a half years old, which means her chance at re-adoption is lower than as if she was a kitten.\nI don't know what to do. It's one thing with the allergies, but it's all too much. I feel horrible she's stuck in my room, I feel horrible that I am considering returning her or trying to rehome her to a friend. I'm in way over my head.", "679" ], [ "First time giving my (ESA) meds (Trazodone)\nHey everyone! I am moving cross country and originally my (ESA) Siberian Husky was supposed to be shipped cargo but his carrier size is WAY oversized.\nI ended up renting a car and we're due to make the drive from Philly to Atlanta in two days, however I did take him for his annual checkup and told the doctor how he acts in the car, he's not terrible but he whines alot and tries to move from the back seat to the middle console to be next to me.\nThe vet prescribed him Trazodone but I have not given it to him yet as when we are out and about he never exhibits a behavior which warrants needing it. He does have separation anxiety when I go to work or school (Freshman in college).", "63" ], [ "He wants to be near me every second and whines or has even peeled back the metal framing of my current house door because he heard me talking to the mailman on the ring camera outside while I was on a trip for a week.\nSorry for oversharing but I have been trying to talk to other pet owners that have given their pets medications for separation anxiety and tranqs, will the trazodone mellow him for the 12 hour trip and if so how soon before the ride should I give it to him to see a difference. This is my baby and I don't want him to be a zombie but I also want him to be able to use the bathroom when we stop on the road.\nI take Trazodone and know at the MG I take (which happens to be his MG too) I wake up sh*tfaced and stumbling around. I want him able to use the bathroom and have the cognitive ability to eat.", "210" ], [ "Dog deteriorated suddenly and needed to get put to sleep. Need advice on cause\nHey. Posting again as I put a post up a few days ago explaining what had happened to one of my dogs. I'm still looking for answers as this is absolutely devastating for my family. I am in the United Kingdom. My dog was a 9 year old Yorkshire Terrier with no previous health issues, no tumors, no murmurs. She was in a clean bill of health. No garden treatment, no rat traps, ant traps or any sort of insecticide or Rodenticides are in use anywhere.\nX-rays and bloodwork showed absolutely NOTHING. Literally, this happened out of the blue.\nIt happened on Monday. I came home from working nightshift at 8am(BST) She was fine, had a bit of toast that my mum gives to her and playful as ever. When I went to bed and woke up, I noticed that I could hear her vomit.", "664" ], [ "This by itself isn't usual as sometimes she gets an upset stomach. But she continually vomitted one after another. To the point her breath began to become very laboured, almost like she was struggling.\nMy mum decided to take her to the vets and even getting up by car, she was seemingly worsening. The vets tried all they could and even said she was going cold, to the point a heated blanket needed to help stabilise her temperature. The vets declared her critically ill and our option was to try and take her over to Edinburgh, which is no easy journey to a veterinary college. But, she didn't have any guarantee she'd survive the trip there. Or even if they did an operation on her. There was only a chance that paying many thousands of pounds would keep her safe and alive, no surefire guarantee she'd make it.\nSo we had to difficult decision of not making her suffer anymore due to her being in such a critical way. I'd just like to know some possibilities of why she changed in a few hours to the point of needing to be put to sleep. We're all very heartbroken as a family and just can't grasp how.. this happened.", "664" ], [ "Any advice on dog wards?\nI have a 10 year old poddle mix and I noticed that he has a couple of wards on his back. During his annual physical a couple of months ago the vet told me that wards are normal for older dogs and that I shouldn’t worry.", "63" ], [ "However lately they seem to be growing and I am not sure what it means. His vet won’t have any available appointments until the end of August and I am not sure if I should wait until then or take him somewhere else. I would really appreciate any advice from other dog owners who have experience with this.", "961" ], [ "Should I return her?\nI have an adult male small dog. Looks like a poodle, but smaller. He’s 6 years old, has a reserved personality, doesn’t like anyone disturbing his business. We had to take care of his brother for some time but my dog never accepted him.", "888" ], [ "He would get super angry, bark at him and would bite him. So we decided to not take care of the brother again. I thought this behavior was because both were males.\nThinking things would be different with a female dog, I brought a female husky puppy. Same thing is happening, and I am scared they don’t like each other ever, and one the husky is bigger they’ll fight a lot 🥲 she learned to bark and always barks at him when she gets mad..\nI don’t know if I should return her, my mom y telling me that’s the best hung to do right now …", "888" ], [ "Am I too late to vaccinate my cat?\n6 months ago, I found a kitten near trash dumpster. I gave him some food and he started to follow me back so I took him in. I am not a cat person and I was in no way financially fit to even vaccinate that kitten.", "176" ], [ "I just managed to skip my lunch few times a week to get his cat food and litter. Infact, I hid him from landlord because I couldn’t pay for him. I did post on facebook so someone could adopt him but I haven’t had any", "940" ] ]

[ 145, 11073, 5405, 8501, 7805, 451, 321, 4222, 1724, 7911, 210, 2453, 10695, 1995, 8815, 9653, 1747, 1225, 5675, 4211, 7428, 10196, 10282, 9020, 10180, 4771, 10635, 3399, 8894, 8662, 5775, 7560, 8290, 2567, 1459, 4138, 2650, 4738, 7799, 10152, 8597, 11008, 5469, 1572, 7122, 6149, 1700, 1101, 4693, 3078, 10116, 429, 704, 7454, 5258, 6953, 4910, 4930, 3332, 7624, 6161, 7863, 613, 2249, 8587, 10325, 10987, 2336, 8006, 7955 ]

[ [ "Engraving Photos on an Egg\nIntroduction: Engraving Photos on an Egg\nI know that there are already many existing works where eggs are engraved with a laser but I wanted to experiment with the possibility to engrave photos on an egg to see if it is feasible to get something similar to gray levels. I'd say the results are remarkable.\nSupplies\nA CNC, if you don't have it why don't you think to build one ? Have a look to https://rootcnc.com/, I started from there\nA laser mounted to it\nA support connected to X or Y axis with an adapter\nA little bit of foolishness :-)\nStep 1: Building the Fourth Axis Support for Your CNC\nThis step is obviously not mandatory if you already have the fourth axis. In my case the CNC comes from the fantastic root-cnc project (https://rootcnc.com/) that I built several years ago, so I had to build the fourth axis from scratch.\nYou can see in the pictures the 3d-design and the cutting planes. It is designed to be cut from 8mm plywood.\nOne side houses a Nema 17 motor (more than enough to rotate an egg :-), on the other side I mounted a flange (KFL-000-10 mm) having an internal diameter of 10 mm. I used this flange just because I had it available but is certainly oversized.\nIn the pictures of the base I have indicated the pockets and their depth. Of course the position of the fixing holes depends on your CNC bed and should be adjusted accordingly.\nA 10 mm threaded bar is inserted in the flange.\nStep 2: Installing a Laser on Your CNC\nThe laser I used has a nominal power rating of 5.5W (although I have my doubts about the real power). You can find it on aliexpress, at this link\nhttps://www.aliexpress.com/item/32559183201.html?s...\nI installed the laser in a can of shaving foam and I built adapters for the spindle mount of my CNC (A Kress FM1050).", "776" ], [ "This way it is quite quick to change the tool from the spindle to the laser and the can has just a diameter of 53mm, perfect for my setup :-).\nOn top of the can I installed a fan that sucks in the air, in this way you get the double effect of keeping the laser cold (essential for the life of a semiconductor laser) and sucking in the fumes (I usually connect a pipe to take the fumes out of the window) . The small console you see above contains an arduino and a display to constantly monitor the temperature of the laser and, if it exceeds 60 degrees celsius, pause the CNC. On the bottom there is a small fitting to pick up the fumes as close as possible to where they are generated thus avoiding to dirty the laser lens. Embedded in the fitting I designed an optical distance sensor, very useful to maintain a constant focusing distance and, concerning the egg, get a depth map.\nObviously you can use any other mounting method, but remember to keep the laser temperature under strict control.\nStep 3: Adjusting the Step/mm in GRBL for the New Axes\nIf you are using GRBL and the X axis for the rotation, you have to adjust the $100 setting, i.e. the steps/mm, according to your microstepping setting for the axis trying to maintain the best possible aspect ratio.\nIn my case I have a NEMA17 motor doing 200 steps/revolution. If MS is the microstepping value, a revolution requires 200*MS steps.\nI evaluated the egg (maximum) diameter as 45 mm, this means that the circumference is 45*PI=141.3 mm\nSo, in order to have a drawn circle to correspond almost to an etched circle we need to set $100= 200*MS/141.3, assuming the microstepping 32 (as in my case) we should set $100=45.29..\nIf we put 45 we will have a revolution corresponding to x=6400/45 = 128 that is a good approximation and gives nice numbers. Of course, you are free to adapt the numbers to the circumstances..., and to the eggs :-)\nFor my eggs also the \"usable length\" is about 45 mm.\nThe speed and the accelaration have to be adapted to the other axis settings, in my case I have\nSpeed (X axis): $110=3000\nAcceleration (X axis) $120 =60\nDon't forget to put $32=1 to enable the laser mode (in GRBL 1.1).\nStep 4: How to \"couple\" the Egg ?\nFor this purpose you need something soft enough to not damage the egg.", "152" ], [ "3D Printed 500x400mm Router CNC\nIntroduction: 3D Printed 500x400mm Router CNC\nFirst of all, I really doesn't like fuss and feathers. Because of that I put the useful area size in the Instructable’s title. The real machine size is around 740x740mm. So, be conscious that you will need some space to place this machine.\nIn the 2018 I has wandering on the internet when I saw the Router CNC from the Brazilian YouTuber <PERSON>. His project is called \"Revolution 2\". I fell in love right away! Unfortunately, in those days I wasn't able to make the polymer parts, but those days are gone: I have a DIY 3d Printer!!! Now I'm the king of the hill!!! And more than this, I have a GREAT trainee, a real DIY guy: <PERSON>. Making this real is all his credit.\nThe main goal of this Instructable is to describe the assembly of the machine, since all parts are available in the Conrado’s web site \"Atividade Maker\" (sorry, it's in Portuguese). BTW, we redesign ALL the polymer parts in Autodesk Fusion 360 to make the assembly guide, so, you can ask me and I can send you the whole thing!\nYou may be asking yourself: \"Does a 3D Printed 740x74mm sized Router CNC works properly???\". Come with me to discover it!!! (in the time this introduction was written the CNC have milling not yet.)\nI hope you enjoy this Instructables as much as I did!!!\nSupplies\nTips:\n* Most of the parts was printed in PETg.", "116" ], [ "I strongly recommend it because of the mechanical stress.\n* Use as much as possible lock nuts. The router machine use to shake so much and standard nuts just run away.\n* Since in this project all the plates are 3D printed in PETg, we decide to use standard washers, but you should use lock washers if your plates are made from some harder material.\n* For this project we've just saved the Conrado's SketchUp files into STL format, sliced in Ultimalker Cura and printed. All the animations are made from the real assembly sequence. Our Fusion 360 files have been redesigned to allocate the lock nuts, simplifying the assembly for future makers. Oh, yeah!\nStep 1: Step 1: Z Axis Assembly\nAs you will see during this Instructables, <PERSON> did an excellent job in the assembly animations, so, there is no much to say buy the parts needed in this step:\nAssembly order:\n1. Brass nut in the brass nut support; (first animation)\n+ Main parts: Brass nut support (3D printed), brass nut.\n+ Small parts: 4x M3x25 screws, 4x M3 washers and 4x M3 lock nuts.\n2. Brass nut support in the Z baseplate; (second animation)\n+ Main parts: Z axis baseplate, brass nut support assembled.\n+ Small parts: 2x M5x25 screw, 4x M5 washers, 2x M5 lock nuts.\n3. Pillow blocks in the Z baseplate; (third animation)\n+ Main parts: Z axis baseplate, 4x pillow blocks.\n+ Small parts: 16x M5x25 screws, 16x M5 washers\n4. Router supports in the Z baseplate; (forth animation)\n+ Main parts: Z axis baseplate, 2x router supports.\n+ Small parts: 4x M5x35 screws, 4x M5 washers, 4x M5 lock nuts.\nResume parts:\nMain parts:\n* 1x Z axis baseplate (3D printed part)\n* 1x Brass nut support (3D printed part)\n* 2x Router support (3D printed part)\n* 4x Pillows blocks 16 mm SC16UU\n* 1x Brass nut (T8, Pitch 2 mm, Lead 2 mm)\nScrews:\n* 4x M3X25 mm\n* 18x M5x25 mm\n* 4x M5x35 mm\nWashers:\n* 4x M3\n* 24x M5\nNuts:\n* 4x M3 lock nuts\n* 6x M5 lock nuts\nStep 2: Step 2: X Axis Assembly\nAssembly order:\nPart 1:\n1. Pillow blocks in the X baseplate; (first animation)\n+ Main parts: X axis baseplate (3D printed part), 4x pillow blocks.\n+ Small parts: 16x M5x25 screws, 16x M5 washers\n2.", "116" ], [ "Presentation Stand - 3D Printed\nIntroduction: Presentation Stand - 3D Printed\nIf you are looking for a presentation stand for a special object ... this one might be it!. The different 3D models shown in the video or in the pictures give you an impression how it could look like. Of course the possibilities of 3D printing are not as manifold as shown in the video.\nThe transparent nylon thread makes it look like the plate is floating between the open arcs.\nDimensions: L200 x H158 x W160mm. Base Ø 80mm, plate Ø 105mm.\nThere are 4 files to print for this object:\n* Arc_big.stl\n* Arc_small.stl\n* Base.stl\n* Plate.stl\nAfter you have printed these parts ...\nRemark: As all parts are designed to fit very precisely, it may happen that you have to rework one or the other part a bit with sandpaper and/or cutter due to different dimensional accuracy of the printers and the different behavior of the filaments.\nSupplies\nThe plate is held in position by 4 nylon threads. For the assembling you need:\n* Nylon thread Ø 0,35mm\n* Superglue\n* Some patience ;-) … when positioning the plate\nStep 1: Inserting the Big Arc\nStart by gluing the big arc into the base. I used superglue. A small bulge in the middle of the arc will help you with the alignment.\nPress the arc firmly into the recess. Hold it for a moment!\nBefore you continue, wait a little while for the glue to set.\nStep 2: Inserting the Small Arc\nThen you can insert the small arc.", "646" ], [ "I used a screwdriver to press it into place.\nTo ensure a good fit, the fitting accuracy is very tight. It may be necessary to correct the fit with a cutter knife or sandpaper.\nStep 3: Attaching Nylon Threads to the Plate\nNow prepare 4 nylon threads with approx. 20-25cm length. Insert them from the bottom of the plate. A multiple knot is enough to fix the thread to the plate.\nStep 4: Place and Align the Plate\nStart by hanging the plate into the big arc. The thread length between the tip of the arc and the plate should be about 6cm.\nThere is a small slit (W 0,3mm) at the end of the arc - apart from the hole - to trap the thread initially for temporary fixation.\nThen take the threads for the small arc and proceed in the same way.\nWhen the plate is aligned horizontally - at a height of about 10cm from the bottom - you can pull the thread through the hole 1-2 more times and clamp it. This should be enough for a permanent fixation. Now you can cut of the thread ends.\nDue to the material (PLA) the load is limited ... about 150 gr.\nStep 5: Color and Material Suggestions\nSome more color and material combinations in 3D model.", "56" ], [ "Lamp \"Sunset\" - LED 12V - 3D Printed\nIntroduction: Lamp \"Sunset\" - LED 12V - 3D Printed\nI came up with the idea for this lamp when, just for fun, I held a light source behind the Fruit Basket \"Cradle\", which I published here some time ago (https://www.instructables.com/Fruit-Basket-Cradle-3D-Printed/).\nIf someone had told me a few years ago that I would ever print a lampshade, I probably would have thought he was crazy. Now it has happened!\nA lamp with half sunset colors, with a plain monochrome lampshade or with a classic black and white striped pattern, a lamp whose lampshade and all other parts give free play to the color design! A self-printed lamp, with individual coloring, is always something special!\nA lamp made entirely of printable parts, without any support, easy to assemble and that creates an ambient light!\nAs with some of my other projects you need a little bit of craftsmanship here too, a.o.", "492" ], [ "soldering.\nWith 3000K the light is considered warm white. The power consumption is 2.5 watts.\nDimensions:\n* H over all 29.5 cm\n* H lampshade 25 cm\n* Ø foot 15 cm\n* Ø lampshade bottom 12.5 cm\n* Ø lampshade top 10 cm\nFiles to print:\n* Lamp_Base.stl\n* Lamp_FootDown.stl\n* Lamp_FootTop.stl\n* Lamp_GlassRingBottom.stl\n* Lamp_LampshadeBase.stl\n* Lamp_LampshadeGuide.stl\n* Lamp_LampshadeStrut.stl (20x)\n* Lamp_LampshadeTopGrid.stl (Lamp_LampshadeTopClear.stl/Lamp_LampshadeTopClosed.stl)\n* Lamp_LEDSocket.stl\n* (Lamp_LampshadeLockingRing.stl)\nPrint Settings\n* Printer brand: Prusa\n* Printer: MK3S / Mini\n* Supports: No\n* Resolution: 0,20\n* Infill: 5%\n* Filament brand: Prusa; ICE\n* Filament color: Galaxy Black; Wintershine White, Romantic Red, Young Yellow\n* Filament material: PLA\nRemark: As all parts are designed to fit very precisely, it may happen that you have to rework one or the other part a bit with sandpaper and/or cutter due to different dimensional accuracy of the printers and the different behavior of the filaments.\nSupplies\nFor this project you will need:\n* 1x … Ø 99 mm polycarbonate twin-wall sheet, thickness 4mm or 6mm (or transparent polycarbonate glass)\n* (1x … Ø 86 mm polycarbonate twin-wall sheet, thickness 4mm or 6mm (or transparent polycarbonate glass))\n* 8x … self-tapping screws Ø 2,2 or 2,9 x 9,5mm\n* threaded screw Ø 4x20mm and matching nut\n* switch wire, ca. 10cm\n* Drill, Ø 2mm\n* Fretsaw\n* Soldering Iron\n* Solder\n* (Super)glue\n* Sandpaper\n* Phillips screwdriver\n* piercer\nFor the light installation you need:\n* AC/DC Socket 5,5/2,1mm\n* 4G bulb socket\n* 2 Position Mini Toggle Switch\n* 4G LED bulb 2,5W/250Lm IMPORTANT!: I do not advise the installation of a higher wattage bulb, because of too much heat development!\n* 12 V AC/DC power adapter\nAll these parts you can find here:\n* Light: Trango 3er Pack LED Leuchtmittel mit G4 Fassung zum Austausch vom G4, MR16, GU5.3 Halogen Leuchtmittel TGG415-2.5W - 12V AC/DC - 2.5 Watt 250 Lumen mit 3000K\nhttps://www.amazon.de/dp/B00LC0DSEC/ref=cm_sw_em_r...\n* Bulb socket: 10 Stück MR16 GU5.3 MR11 GU4 Fassung 12V mit Kabel\nhttps://www.amazon.de/dp/B00279SBDA/ref=cm_sw_em_r...", "858" ], [ "Fruit Sorter Robot Using Flexible Gripper\nIntroduction: Fruit Sorter Robot Using Flexible Gripper\nHello Everyone, thank you for showing interest in our project. In this project, we are showing a fully automated robot that sorts fruits and vegetables based on their color.\nThe project happened in the context of the Bruface program and more precisely in the mechatronics 1 course. The Brussels Faculty of Engineering (in short, Bruface) is a joint initiative between Vrije Universiteit Brussel (VUB) and Université Libre de Bruxelles (ULB), offering a broad spectrum of fully English-taught Master Programmes in the field of Engineering.\nThe team is composed of 3 members\n* <PERSON>\n* <PERSON>\n* <PERSON>\nThe main purpose of the Mechatronics course is to teach both mechanical structure and electronics. This is the reason why we chose a robot with a mechanical solid structure and a moving flexible gripper able to detect the fruit in a certain zone and sort them by color.\nInitially, we started with a silicone molded soft gripper for sorting vegetables/fruit based on its matureness but as the laboratory was closed for November due to coronavirus and very little time was available to create the soft gripper we switched to a flexible gripper instead of a soft gripper by readapting this gripper found on thingyverse : https://www.thingiverse.com/thing:2316823\nThe project took 3 months to complete but do not worry this project will regroup all the files needed for the building of the vegetable/fruit sorter robot.\nThe project is about the fabrication of a vegetable/fruit gripper sorter. The gripper is made in a flexible way to be able to pick fragile fruits of various sizes.", "949" ], [ "The total budget you should consider to make this project is around 100-150€ (120-180$) and it will take you 15 to 20h of work to build the entire prototype. We advise you to have someone to help you at some point when you will build the global structure to hold the plate while you screw them together.\nStep 1: Mechanical Design\nThe design looks like this with two laser-cut feet with small supports to ensure stability.\nThe motion is driven by a belt and a stepper motor fixed to the right feet and a lead screw and a stepper motor fixed on the top.\nTwo linear rods of 70cm are attached between the two feet on which the gripper will slide thanks to linear bearings.\nTo ensure a good motion in Z, two linear rods of 22cm are also fixed with the motor and sliding in linear bearings in the fixation.\nThe gripper in itself is driven by a 3D-printed rack and pinion and a servo motor controlling the opening and the closing of the gripper. It is a flexible gripper allowing it to take various sizes of objects.\nNeeded Material\nAll the needed material is in the list below.\n* tons of screws and bolts M3 (for the laser cut assembly mainly) and M5\n* 2 Linear rods 8mm diameter 70cm long\n* 2 Linear rods 8mm diameter 22cm long\n* 1 Lead screw and trapezoidal nut 8mm diameter 15 cm long\n* 1 Trapezoidal belt 5mm width, 1.4m long\n* 1 Arduino Uno\n* 2 Stepper motor NEMA 17 (needed torque around 20Ncm at least)\n* 1 Shaft coupler 5x8mm\n* 1 pulley 5mm inside diameter\n* 2 Stepper motor drivers DRV8825\n* 1 Servomotor MG996R\n* 1 Ball bearing 5mm inside diameter, 13mm outside diameter\n* 5 Linear bearings 8mm inside diameter,15mm outside diameter\n* 1 color sensor TCS3200\n* 1 Laser range sensor GP2Y0A21\n* 2 end switches SS-5GL\n* 1 Potentiometer\n* 1 Button\n* 1 Voltage source 12V (we chose a 12V PDC004 to power the robot through usb-c)\n* 1 DC-DC Voltage step down power module LM2596\n* Cables\nNeeded Prerequisite\nTo finish this project, you will need some basic electronic knowledge in order to connect everything and most importantly, not burn a component or even worst your laptop. Also, you will need to solder cables and components so either you will need to be good at soldering or good in electronic debugging to find the problem after some soldering errors (trust me it happens very often). Same for the coding, we will give you every codes and files to build the project but bugs may occur, knowing the basics about Arduino coding is good to have.\nTools\nLots of pieces are laser cut or 3D printed so you will need access to both a 3D printer and a laser cutter.", "949" ], [ "Jigs for Drilling Rods, Bolts, Nails, Screws, Shafts, Nuts Etc.\nIntroduction: Jigs for Drilling Rods, Bolts, Nails, Screws, Shafts, Nuts Etc.\nIt's usual practice for DIY fans to make holes in rods, screws, shafts, nuts etc. I don't have a boring mill at my home, just a screwdriver 12V, so I had problems when I wanted to do it. My screwdriver walks across a rod and does not want to keep a direction.\nI found a solution with my 3d printer by designing a drill conductor every time when I need to make a hole in a small metal stuff.\nAt the beginning, I was going to use special steel bushings that are usually used in drill conductors but I caught an idea to use bearings for fixings a drill in a certain position.\nBelow I am demonstrating how to make a perfect hole in a screw or in a nut by my conductor.\nSupplies\n* 3d printed parts for the conductor (models are attached)\n* 2 bearings with an internal diameter equal to your drill diameter\n* Screws\nStep 1: Prepare STL Files\nDownload Fusion360 model files and fill out Favorite parameters (see screenshot).\nOpen 3d view and make sure it looks as expected.\nExport STL files by menu File -> Export\nStep 2: Print 3d Models\nFor the nut conductor, you need to print two pieces of the model.\nThe rod conductor is a solid part.\nUse different parameters according to your requirements. For big screws and nuts use 1.2 - 3 mm for walls to fix them hard.\nStep 3: Reinforcement of the Rod Conductor (Optional)\nI crashed my screw conductor 2 times so I decided to add some reinforcements to make it stronger. Usually, the vibration of a drill breaks the conductor closely to the rod's hole. So I added reinforcement slots and you can fill them with thin screws.", "582" ], [ "Also, you can specify your own size of the reinforcement screw in the Params spreadsheet (see the Step 1).\nStep 4: Assembly of the Rod (Screw) Conductor\nPlace the bearings into the rod conductor and it's ready to be used.\nStep 5: Assembly of the Nut Conductor\nThe nut conductor contains of two parts so it should be assembled every time you want to use it. You can use screws M3 or use a vise to fix all parts together.\nStep 6: Test... Drilling...\nNow it's time to test it out. I use my usual 12V screwdriver with a 3mm drill for metal. It takes 2-3 mins to make a perfect hole. I hold it with my hands without any special vise.", "226" ], [ "Mercedes-Benz Rotating Logo\nIntroduction: Mercedes-Benz Rotating Logo\nTwo weeks ago i got my first 3D printer and started creating in the wonderfull world of 3D printing. During the configuration of my printer i printed many different patterns of the Mercedes-Benz star, but most of them were not at the expected form, so decided to make something out of them. By joining some stars together i created the form of the first picture. The geometry which surrounds the star looks more like a tetradecagon than a circle, which made me print more and more times in order to achieve the desired result.\nWhen i saw the contest \"Make it Move\" i said why not? and decided to make it rotate. Later i added a LED at the center of the star but this design must be further developed because the mechanism which transfers the power supply to the rotating star is not working efficiently.\nIf you like my project please vote my entry at the \"Make it Move\" contest.\nSupplies\nFor this project you are going to need:\n- 3D printer\n- PLA fillament in different colours and glow in the dark series\n- DC motor\n- LED and thin wires (optional)\n- 3V battery holder\n- switch\nStep 1: Printing and Sanding the Parts\nI have designed all parts with Autodesk Inventor, the Design Accelerator is the best way to design gears quick and easy, then i converted the files to .stl.\nStart by 3D printing the parts, you can find the .stl files on the list below. For some of the parts i used the glow in the dark filament in order to have the result shown on the video when the lights go out, these parts include both sides of the star, some gears and of course the base with the old Mercedes-Benz logo.\nThe parts were printed by the Creality Ender 3. The bed temperature was set to 60° C and the hot end to 210° C while using PLA filament, for better surface results i reduced the feed rate to 80%.\nBefore printing the parts make sure that the scale is set right, all parts should be printed in 1:1 scale, this way you will avoid assembly fit problems. Since you have all the parts printed you should clean and sand imperfections like over-extrusions or stringings.", "116" ], [ "This is very important for the gears, please control if the gear teeth are meshing each other the right way and rotate freely after placing them on their axles.\nStep 2: Assembly of the Star\nUse glue to join both sides of the star together after placing the pin in the slot at the centers, then clamp them and give the glue enough time to dry. Pay special attention by alligning both ends of the base foot of the stars, this parts must fit in the slot of the last gear.\nStep 3: Assembly of the Base and Gear Support Frame\nThe cylindical base is the mounting component of the electric motor, the switch and the battery and together with the gear support frame and the gears they consist the main motion transmition unit of the project.\nFisrst of all place the motor in the frame, mount the motor support and fix it with tie wraps to the base. Then glue the gear support frame to the base, let the glue dry proceed to the next step.\nStep 4: Mounting the Gears\nBefore placing the gears to their axles on the mounting frame add some grease to the axles and the gear teeth of all gears. You can find the assembly sequence on the first picture. The last gear to be placed is the smallest gear which transmitts the rotation from the motor to the rest of the gear reduction.\nStep 5: Assembly of the Gear Cover\nThe gear cover and the old glow in the dark Mercedes-Benz logo should be glued together and clamped. Then the three feet of the cover should be placed in the holes of the base. Pay attention by placing the feet to the base holes, the grooved foot must be placed in the hole between the gears, otherwise the gear will be blocked and will not rotate.\nThe last thing is to assembly the star and the last gear.\nStep 6: Wire the Motor Electrics\nThe motor is powered by a 3V battery pack and between them there is a switch. Enjoy your rotating star, day and night!\nIf you like my project please vote my entry at the \"Make it Move\" contest.\nStep 7: More Ideas\nThe project started as i tried to set my new 3d printer, so i have printed several star until i achieved the desired print result. This way i have printed more than a dozen stars, with them i created a static logo.\nFurthemore i am developing a design to integrate a LED in the center of the star and i m going to post soon the results.\nIf you like my project please vote my entry at the \"Make it Move\" contest.", "226" ], [ "Mini Regulated Power Supply Unit [UPDATED]\nIntroduction: Mini Regulated Power Supply Unit [UPDATED]\nI've always been attracted by compact instruments, and I love to buy electronics kits and build small and pretty devices.\nYears ago I bought a regulated power supply unit (PSU), which has the interesting feature to vary current intensity other than voltage.\nVoltage (Volt) is the \"pressure\" of the electric current, and intensity (Ampere) is the \"flow rate\" of the current. You have a big power (Watt) when you have a high flow which push hard ;-)\nStep 1: Dismantling and Adapting\nAs first thing I tested my device, and I started to imagine the best way to build something around it. As you can see I connected it to the battery pack I lately refurbished with ten 18650 cells. Since that Li-Ion power bank is quite powerful now, I wished to take the best advantage from it. I also thought to incorporate the device inside the battery pack, but space was not enough. This way the regulated PSU can be powered by any battery or wall plug power supply.\nSeparate the top and bottom boards unscrewing the four screws, which act as connectors too.\nStep 2: Think Bigger\nIf you need to regulate voltage and current often, those small pots are not convenient, and although they're quite precise, they need a lot of turns to travel from low to high. So I decided to substitute them with a couple of bigger pots. I had to choose between many types and shapes, and I opted for two classic pots.\nStep 3: Soldering External Controls\nThe value of the new pots is the same, 10Kohm, the central pin must be soldered in central position also for new pots, and to find the right position of the other two pins you can make a try, but if you look on the side of the original pots you can see a diagram and the pin corresponding to clockwise rotation. I also added a 2.1mm DC power socket connected with wires at plus and minus DC-IN pads, but then I inserted a general switch on the positive wire. As outputs I used two (red and black) banana plug panel sockets.\nStep 4: Design and 3d Printing\nI think design is the funniest part, as you're totally free to chose any detail, from dimensions to knobs position, from color to grid shape. After decided which components to use, I spent one hour or two drawing, taking measures with caliper, calculating the minimal space required inside the case.\nI would't deepen the process to draw in 3D with Rhinoceros since I already explained some basics in other tutorials.", "267" ], [ "You can also use OpenSCAD, which lets you to develop a parametric 3D model. Obtained a good 3D model, which I attach here for you, I exported it as .stl and I loaded it in Cura from where I saved the G-code to upload into my little 3D printer. The result was perfect at the first try, but I added some improvements in the final version of the file.\nStep 5: First Test\nAfter having waited something like 5 hours the end of the print, I couldn't wait to try the case. So I plugged in position all the parts, and fortunately I didn't find obstacles.\nStep 6: Some Weight\nWhen you pick up a tool, a gadget, an object in general, the weight transmit a sense of toughness and quality. This is the reason why I decided to use a thick iron plate as bottom. I drilled four little holes for the screws, I removed the rust, and left two big hole there were before. I attached a thick tape on the inside face, to avoid short circuits.\nStep 7: The Cooling\nI red that this device hardly keeps 5A (maximum load) especially for long time, without heating too much and turning off. So I added in the design a little motor and a very little fan, working always whenever the PSU is turned ON. The motor work at only 3V, consumes a few mA, and makes some noise. If I had owned a small enough brushless motor, I would had used it, because of the reduced noise and the longer life.\nThe little fan is 3D printed, I made a minor mistake in design and I couldn't use all the space, but I didn't want to make the case again only for that. I attach .stl file of the fan.\nStep 8:\nTo power the motor I used a voltage regulator https://www.mouser.it/_/?keyword=L78L33, which only keeps 100 mA load, but it's perfect for this purpose. Then I also added a 40ohm resistor to reduce speed and noise.\nYou can see the black small 3.", "646" ] ]

[ 8244, 10941, 8423, 10808, 11175, 5118, 8789, 4734, 2175, 4903, 8867, 5243, 277, 3131, 6981, 1771, 1328, 4848, 4792, 3574, 7255, 5438, 2717, 4550, 9434, 1162, 6286, 5281, 2107, 9573, 1961, 9953, 3614, 8252, 3144, 2554, 9828, 4477, 677, 5033, 7869, 2603, 4194, 2353, 3692, 2822, 7791, 9551, 170, 1067, 559, 11414, 5688, 7548, 1648, 6449, 541, 4511, 9340, 9284, 11001, 2933, 4923, 1796, 11274, 10886, 2378, 5667, 7961, 2637 ]

[ [ "<PERSON>\nThe person who wrote up the synopsis you see on letterboxd must have slept through the movie. Even the little girl at the end knows that \"the harpies were not Indians\".\nThe film teases you with both possibilities: that the inexplicable goings-on are ghosts held by the forest, or people held by their own madness and evil.\nIt's fun to ponder the latter. <PERSON>, who the film's lesser narrators--the children--see as a magic fairy, basically offers a human explanation of fairies. Some folks reject religion, or \"progress\", so thoroughly that they just go live in the woods. <PERSON>'s path to that point involves acting first as a crime scene detective. <PERSON> eats dirt--something we would pathologize as \"pica\"--but her work is not substantively different from that of modern footprint or chemical analyses.", "295" ], [ "Her methods also involve attempting to recreate the costumes of the valley's attackers: she dresses herself in feathers to balance the attackers' wood-and-mud camouflage. (The mud itself is revealed to have makeshift poultice qualities, generally healing the bodies of those who hide and sleep in it--unless, that is, their wounds are large enough for insects to infest the body.) <PERSON>'s work reveals to her that the previous group of settlers* had experienced infighting that led to fatal violence. Her final discovery is that those settlers had been holding toads in their mouths for their psychedelic qualities. If this wasn't the genesis of their madness, it certainly kept them that way.\nThe Shawnee concept of demonic activity--evil pools underground in certain places--makes the valley, in this \"natural\" explanation, a place where the chemical runoff of the forest collects, and makes both \"healing\" pools as well as animals who have become semi-poisonous in the course of their evolution.\nBut the preacher sees everything that is easy to get as a gift from God. A ruined shelter in an empty valley is divine provenance, not--as Marion can see--a clear sign that the place is unlivable and avoided by the locals. As <PERSON> tells us at the end, the smart thing to do is recognize that the valley has some good qualities, from afar; because, without an understanding of the environment, you will always be burned by it.\n*were they French?", "45" ], [ "<PERSON>\nA deadbeat dad joins the Russian space program so that he can come back a hero and actually *be* something to the son he abandoned. He comes back with an alien inside him that comes out at night and eats the most vile of prisoners.\nThis is a pretty forceful statement about the male psyche and the violence wrought upon it when it becomes part of anything that the military has an interest in. Even the most un-\"heroic\" actions, like going to space (\"sitting in a tin can\", as one character refers to it) are inseparable from the military's goals of control through deadly weaponry, and give support to the deaths of people.", "999" ], [ "This is <PERSON>'s (the woman scientist) philosophical opposition: no matter how vile the criminals are, they are still people.\nAnd so, on the level of the individual male, the honor he hopes to gain in his child's eyes by being a hero (or maybe the ability to provide that comes with being a national hero) is revealed to be useless, and a deadly detour from actually being, you know, anywhere physically near the child to do anything for them. The man wants his son, and is ashamed of how the military turned him into a monster and made the world that less safe for all children.\nThe alien feeds on cortisol, produced when humans are afraid. The military feeds on fear, and puts this alien into every man who signs up to be any kind of soldier.", "295" ], [ "As to the emphasis on <PERSON>'s psychological state, I'd suggest that the obsession with finding the bug is not as interesting as the larger obsession with professional perfection. He's come across someone who can bug better than he can. If he figures out the puzzle, he can regain his position of professional perfection. Until then, he has met his match, and he's not the professional he thought he was.\nRelated, his professional perfection, for him, means doing everything himself. He doesn't buy: he builds his own. He doesn't even practice with a band. He practices alone with a tape as proxy for accompaniment. That he practices alone mirrors his need to be perfect alone, as opposed to having the perfect team--employees who he can learn from as much as teach. Such aversion to others may derive from paranoia, as does his desire to snoop on others. This, I think, is the more profound comment on his psychological state to be inferred from the scene, not that he is paranoid about what may not even be a bug.\nI wouldn't worry too much about FFC's not having a proper solution. \"The Big Sleep\" had holes too (who killed the chauffeur?), because the writers were more interested in character than the puzzle-solution payoff. Some would call it deliberate ambiguity.", "861" ], [ "I call it indifferent writing.\nBut maybe not. He made a mistake about the girl's murder. He gets in trouble when his information is inadequate. He thinks he gets the inside information with his bugs, thus granting him omniscience. He learns that this is not true. Then he tears up his apartment because he doesn't have enough information about the location of what recorded his sax practice. Lack of information is an itch that, lately, he finds he can't scratch. Perhaps FFC was giving the audience a taste of what it felt like to have such an itch by deliberately having no solution to the bug hunt. This seems to be a new take on an old Hitchcockian theme: identifying the audience as voyeurs, as in \"Rear Window,\" showing tortured voyeurs who got their facts wrong due to a few gaps.\nThen there's the <PERSON> theme of the perpetrator of a seemingly victimless crime getting a taste of their own medicine. In \"Rear Window,\" the voyeur becomes the viewed, and gets a taste of his own medicine. Similarly, lying adman <PERSON> (sorry, \"expedient exaggeration\") of \"NxNW\" finds that people no longer believe him, including the police. He gets manipulated by those who practice deceit on a much larger stage.\nAt the end of the film, <PERSON> is now bugged, and it bugs him.\nhttp://www.gradesaver.com/the-conversation/study-guide/summary-part-5-the-murder", "861" ], [ "Art is obsession, and how well (or badly) it's dealt with seems to fascinate artists.\n<PERSON> was the focus of <PERSON> The Crook Factory, a faux-historical novel set mostly in Cuba; and also <PERSON> The Hemingway Hoax, where the eponymous hoax is interrupted by the ghost of <PERSON> itself (maybe, the story isn't all that clear on that). The former book is more about the writer and his effect on the protagonist, an FBI agent, the latter about his writings and he process of writing (even though it's the process of forging prose that will fool experts). Both books are concerned with the effect of <PERSON>'s strong personality on the viewpoint characters. He was a colorful figure, and I wouldn't be surprised ol' <PERSON> is a character in many more books.\nThree installments of <PERSON> Sandman graphic novel concern <PERSON> and the act of writing: more specifically, Men of Good Fortune, A Midsummer Night's Dream and The Tempest are three issues that concern The Bard and his deal with <PERSON>. This mini-arc echoes throughout the rest of the 75-installment tale and concerns preserving great stories, and the sort of immortality an artist can achieve. My favorite line from the entire work is \"The price of getting what you want, is getting what you once wanted.\" (Typed from memory.)\nI'll round this out with a fictional example: <PERSON> is perhaps the most well-known hack writer in American literature. <PERSON> creation was actually based on <PERSON>, and the character's most significant appearance is in Breakfast of Champions, where he finds out that he is the creation of another writer, and he meets his maker near the end of the novel. <PERSON> writes what seems would be terrible stories, and has published dozens of them in his life. However, he has his fans, who seek out their idol's work in porn shops and bargain bins.", "460" ], [ "This endlessly fascinating character has written books he's never even seen a copy of, but are published somewhere. The message seems to be that life is a pointless farce, and there is no message except for what we may read into it. Life may be dreary, but let's laugh at it anyway!\nI also find that, while I'm reading any story with <PERSON> in it, I find myself more conscious that this is a book written by a writer, and that these are words on a page. I somehow still care about the characters, especially the \"minor\", insignificant bit-parts.\nSooner or later, I think most artists will create a work that's meta to at least some degree. <PERSON> wrote Psychoderelict, the story of an aging, artistically failing hippie rocker in the modern world; Pink in The Wall nearly dies of a drug overdose before playing a concert; <PERSON> made the wonderfully confusing 8 1/2, a film about a director creating a film that cannibalizes his own life; and (my favorite), [Title of Show], A broadway musical about two guys writing a musical about writing a musical.\nIn general, the theme of mining life for artistic inspiration comes up often. In <PERSON>'s The Tempest, <PERSON> notes that when his son died, he mourned, but was also glad: Now he could write of true tragedy and make the pit weep true tears. In The Crook Factory, <PERSON> notes that everything in <PERSON>'s life was secondary to <PERSON>. <PERSON> is the only writer on this page who did not let his art consume his life, and he's fictional. Similar themes are veined throughout the three non-literary works I mentioned above, and are resolved with varying degrees of healthy outcomes.", "698" ], [ "Miracle Mile\nWatching \"Miracle Mile\" seems like fun, yet it's a deadly serious film overall. You can see the gloom in the writers' faces as this movie proceeds. \"What if we interrupted a romcom with a message from the base of <PERSON>, and we'll make it an apocalyptic \"After Hours?\" Yes, the world will end by nuclear holocaust, and the people in the coffee restaurant on Miracle Mile road know this, including the male lover in that developing romcom.\nEverybody panics, believing what he hears from a stranger's call to a public payphone. The news is confirmed by a government worker with a mobile phone. Coincidentally -- no, not for the screenwriters -- she's reading the Cliffnotes version of Gravity's Rainbow.\nThe fact that there might be a missile hanging in the air, over the entire plot, is about as far as the references to <PERSON>'s dense work goes. We really go into quirky \"After Hours\" mode for awhile, as the male lover, panicked, races around LA to get his new female lover to take her to the airport. Where they are going? Well, nobody really knows, for who can escape nuclear apocalypse?\nThe movie has some great design features, yet it tries to hard at this without thinking through its characters' action. I got tired of asking myself why these characters, believing the end of civilization will happen in just 50 minutes, do what they do.", "829" ], [ "The movie does go in real-time: there's about 70 minutes from the phonecall, and at the 70-minute mark the movie will end.\nSo why does the main character keep leaving her? Why do they keep pausing for dramatic effect? You've got me. This is after all a movie. It is for fun, though I didn't have fun by the end.\nThe movie makes an excuse: as the characters are running through LA at 4:30AM, they pass a sign that says \"Avant-Garde.\" Like the <PERSON> reference, that's about all the avant-garde you will get here. Quirky and strange? Yes. Avant-garde? Not going to happen unless the nukes bring a new color palette to this film.\nI would call this a sped-up \"After Hours,\" which was as much about a lost man's spiritual quest. This one, omitting that though it didn't have to, is more focused on a panicked man's attempt to rescue a maiden from disaster. It could've veered in many wiser and complicated directions, too, and you might feel like I did that the third act is a major letdown.\nThere's much focus on the attempt to get out of LA in an organized way. Maybe that's the point: it's a Hotel California scenario where you can never leave even if that's your heart's desire.", "829" ], [ "<PERSON>\nHaving seen the previous Proletariat trilogy films, I was prepared for something lightly droll. The setup preps us for that. The eponymous girl has a low-life existence, like other '80s <PERSON> characters. She's looking for love. She strikes out repeatedly, matchbook pun intended.\nThings keep going lower for her.\nAnd of course we are in the Finnish version of \"Modern Times.\" The girl might as well be the <PERSON>, who will always find sentimental love in odd places.\nInstead, <PERSON> goes a lot darker. Maintaining his vision that modern Finland is a bleak industrial hellscape, the girl is involved in nothing but transactions. Most of those are condescending. The few words spoken to her -- the few words spoken in the movie -- are insults. Isn't \"Whore!\" one of the first words of the movie? And it's spoken by her father, whom she's supporting, because she bought a pink dress to attract a guy.\nI think this is what <PERSON> would be like he had a more entertaining, sicker sense of humor. The repeated transactions in this movie, highlighted by hands putting Finnish cash on hands or on tables, operate as this society's version of \"friendship.\" In terms of true friends, the girl has none. When she tells her co-worker that she's pregnant, the co-worker just gets up and walks away. Mom and dad hate her.", "80" ], [ "Brother seems indifferent. And then there's the men she would date.\nThat gets me to thinking: if the Tramp were a woman, what would his story have been like?\nMaintained here in this third proletariatian movie is that the Finland within these films has no culture. Well, it has dopey imitative culture: specifically, derivative American music galore. The girl walks around in nothing but soulless places. If only she wandered around that garden more at the beginning of the film ... but anyway, I think the matchbooks are the imitative symbol. The machines produce endless numbers of matches. Great, for what? For the girl, it means cash, that turns into her dad's rent, beers at the bar, and absolutely nothing more.\nAs an fyi, when I talk about horror movies not scaring me in general, when we get to something like \"The Matchbook Factory Girl,\" we have a kind of horror movie in development. In other hands, that's exactly what this material has been: hyped emotionally wrought scenes that expose the inner anguish of the main character, showcasing why she does what she does. <PERSON> finds the opposite style just as effective for the same purpose. In my order of preferences, his style is more effective for this material. Because most of us, I think, quietly suffer like the girl.", "80" ], [ "Big Trouble in Little China\nIn which <PERSON> tests whether <PERSON> could've succeeded in action-fantasy camp. It's a fascinating thought-experiment to me to ask if <PERSON> and <PERSON> switched eras, could one have succeeded in the career of the other? For <PERSON>, perhaps. He sure does have a great 'stache in the Westerns.\nI agree with <PERSON> that lack of characterization harms this film. It is essentially <PERSON>'s truck-driving character running around with several Asian men, trying to find a captured woman.", "698" ], [ "Much has been said about that last fact. I simply do not get into movies that are about other movies, and that's their leading aspect. If you have to know the tropes and then know that the movie is mocking the tropes, and that's the fun of the movie, well, fine. But I do like a bit of a connection to the real-world. And what I see here is so goofball or stereotypical, it just doesn't interest me.\nBut I do like <PERSON>'s score here!", "170" ], [ "By happy accident, I stumbled across this story while looking for something else. It's \"Marooned on Planet Earth\" (1985) by <PERSON>. The only publication listed in ISFDB is the March 1985 issue of <PERSON> Science Fiction Magazine, which must be where I had read it originally.\nMy memory was fairly distorted, so I'm not surprised that nobody recognized it. The fact that the protagonist is a normal person seeking the transformation voluntarily is established in the first lines:\n\"Why do you want to be an alien?\"\n<PERSON> smiled at the question. Wasn't it obvious?\nThe doctor leaned forward, perhaps to get a better look at <PERSON>'s smile.\n<PERSON> cleared his throat, and the doctor's head made a small anticipatory nod. But <PERSON> remained silent.\nAfter a moment, the doctor said, \"I understand. You feel helpless, out of control, yes? Adrift in a lifeboat, perhaps. Rudderless. Becalmed under a broiling sun, yes? You feel your life slipping away, dribbling out, escaping into thin air. You want a purpose for living. You want life to be an adventure. Yes? Is that it?\"\n<PERSON>'s head had started to nod almost from the first and was by now rocking up and down emphatically. \"Yes!\"\nThe treatment involves begin given the illusion that the patient is an alien on a mission:\n...\"Sign both copies. In four months you'll return for an evaluation. Don't worry about remembering, it's all built in.\" He quickly unfolded <PERSON>'s hundreds and gave the bills a snap, peering at them briefly in the window's light. \"Very good.\" He glanced at the signed forms, pulled a carbon for <PERSON>, and shoved the rest into a drawer. \"Relax!\" he said.", "489" ], [ "\"The next thing you know, you'll be waking up in bed tomorrow morning. And when you do--\"\n\"I'll be an alien.\"\n\"Guaranteed.\"\n\"With a secret mission.\"\n\"Absolutely.\"\nThe process is some sort of hypnosis:\nThe alienist's arm shot into the air and wiggled like a drunken snake. Then his fist opened and <PERSON> was staring into a battery-powered Hypno-lite®. Brilliance swelled to a fascinating conclusion.\nAnd that was the end of <PERSON>.\nShortly after waking up, the \"alien\" Xgglm sets about improving the situation of his host:\nNext he examined his unprepossessing host. Another mess.\nLater, when he had consulted information storage devices in the nearby emporium called a \"library,\" <PERSON> confirmed that his adopted body was sheathed in excess poundage of subcutaneous gelatinous fatty cells. Fortunately, there was plenty of easily understood advice concerning the removal of this unhealthy mass, and <PERSON> set about the task with enthusiasm.\nHe also learned that the brain of the beast--which he was forced to use--contained a vast and easily manipulated data storage and retrieval system, virtually empty at present. He commenced filling it with the contents of the library, for it was impossible to know this early in the game what information might lead to his escape.\n<PERSON> concluded he might require an added measure of strength, so he put himself on a program of exercise and muscle building. As the body neared the maximum of its potential, <PERSON> took it outside to cooks its skin in the ultra-violet--a \"tan\" being highly prized by the natives.\nHis mission is apparently nothing more than the need to get off the planet, which will require a ship that can't be manufactured with current technology. To that end, he seeks out a local UFO enthusiast club, where he meets someone that he knew from high school:\nThe group called itself the Extraterrestrial Propulsion Society, and was concerned with the location of alien spacecraft. There was no doubt--judging from the incredible accounts--that these flying saucers (as they were frequently called) were precisely what Xgglm sought.\nWithin minutes he was on the Hollywood Freeway in his new Corvette. He got off at Roscoe, and was soon traveling east into the hill of Tujunga.\nIt was noon and the sun was hot, the air spicy with sage from the chaparral. He pulled up in front of the house listed in the newspaper.\n...\n\"Who?\" said <PERSON>, rapidly searching his memory files. <PERSON>... <PERSON>...\n\"<PERSON>,\" she said. \"We were in high school together. But then you were... <PERSON>, you look great now.\"\n<PERSON> grinned the grin he learned from <PERSON>.", "652" ] ]

[ 3267, 7689, 7040, 977, 1202, 6593, 2243, 6206, 2147, 5236, 5499, 8937, 7614, 6093, 4528, 6855, 11208, 7206, 8112, 7221, 7322, 3217, 5860, 2155, 6930, 5301, 4873, 394, 5063, 10518, 5042, 1280, 5408, 828, 2434, 8703, 907, 10434, 962, 4980, 8289, 6470, 135, 5615, 6275, 1010, 4865, 3739, 10129, 7739, 7247, 7161, 3334, 3301, 8413, 1549, 10931, 5015, 2490, 7789, 8175, 2325, 5119, 7149, 11220, 8101, 6671, 11304, 479, 3483 ]

[ [ "Please check out my other reviews at:\nhttp://www.boardgamegeek.com/geeklist/145695/the-purge-revie...\nConclusion:\nConcordia plays like a throwback to Euro games. Lots of wooden bits, a tad abstract yet with a theme, and plays in about 1.5 hours. The game is meaty without being overwhelming. On any given turn, you have one decision (which card to play), but you have to plan ahead to accomplish your move.\nThere are a few ways to score and while you can do a little of everything, by specializing you can use the modifiers to your advantage. Sometimes this will be a plan coming together, other times you will have to think on your feet.\nThe biggest flaw of the game is the scoring. It is tough to explain to new players and there is a lot of it. Once you master it, it all plays perfectly with the game. I feel you need to commit to the game for a couple of plays. Also, the intermediate scoring rule is a must for the first game (this allows all players to score during the game one additional time early in the game to get the hang of it).\nOverall, I liked the use of a single card per round to keep down time to a minimum. This really kept the game moving. This is a game that could have been bogged down with AP. Instead, the rounds fly by.\nAlso, the decisions you make really feel they impacted the end game scoring. You are trying to out think and maneuver your opponents. You can build houses or expand out, get more people, get more land, get more cards, etc.\nThis game is currently a keeper. After playing it, I was ready for a lighter game as it can be taxing. While not the deepest game on the market, it is a thinker and theme is pasted on.\nComponents:\nThe components are top notch. While the art in the game is limited, the quality of the components is great. The wooden meeples/ships are solid as are the wooden houses. The board is colorful, easy to read, and double sided. The cards feel great in your hands and will last for a long time. The text is big and easy to read. I had zero complaints about the cards or any of the components.\nEverything is made to last and easy to use. This is a good example of a \"classic\" Euro game.\nRule Book:\nThe rule book led me to believe I was missing something, but I was not. The game is that easy to learn.", "336" ], [ "I wish the player aids were better. Instead of a small card with limited text, I wish it included a player aid with more details on final scoring.\nThe explanation of all the cards was fantastic. The rules are pretty easy: play one card and do what it says. Scoring is the beast here and I wish the examples were more plentiful.\nOverall, I'm happy with the rule book. You can literally start playing within minutes and use the \"intermediate scoring\" to quickly get a handle on scoring.\nFlow of the Game:\nThe flow of the game is rather simple, yet your decisions are important.\nAll players start with the exact same cards. The cards allow you to get other cards, build cities, move armies (abstracted; there is no war in this game), sell/buy items at the market.\nOn your turn, you play one card and do what it says (see above). That's it.\nI'll explain a few things that you can do, but this is not a recitation of the rules.\n1. There is a set of cards you can purchase and add to your hand. These cards cost goods. They allow you to do actions (like the cards that start in your hand) and also have multipliers for end of game scoring. These cards will increase your end of game score by a lot. Sometimes your decision is do you buy a card that will help you get \"things\" you need now or that will help end of game scoring. This is something you must balance.\n2. You can move your armies/ships around the board. This will allow you to build houses. By building houses you will score end of game scoring and to obtain goods.\n3. You can buy and sell goods at the market. You have a warehouse that can hold a finite amount of goods. You cannot just ditch goods you don't need/want, so you have to sell them. Money is going to be tight in this game.\n4. You add additional armies/ships to the board. This helps you get around the board to build more houses. Building these houses can increase the amount of goods you can get and scoring at end of game. The number of people you have on the board also scores end of game points.\n5. You can get more goods.", "629" ], [ "Please check out my other reviews at:\nhttp://www.boardgamegeek.com/geeklist/145695/the-purge-revie...\nConclusion:\nMy first few plays I liked the game. I think I now love it. The game continues to get better the quicker it plays. When I play this game, the minutes fly by.\nI played the first video game for about two hours and never played it again. I wouldn't call myself a fan of the video game at all. Yet, I find the board game a ton of fun and very thematic. I really feel like I'm a grunt and trying to survive. Every decision is hard and it does require luck to win.\nThe difficulty of this game is hard. It is a big challenge to win. You need to keep your guys together and also try to run to accomplish the mission. It is so much fun to challenge yourself to fight the bad guys and also run. It is easy to leave a man behind, but then you are not at full speed.\nThe components are fantastic and really shine through. Each mission has three bad guys, which is enough but of course you always want more. I really want a big expansion for this game!\nThere are really hard decision as your cards reflect the things you can do and also your health. So, if you spend a card to shoot, you tire yourself out and bring yourself closer to \"bleeding out\". Whew!\nThe board is modular so it plays different each time, even if you play the same mission (there are a few missions included in the box). I have to admit this game is hard. When you do win, you will celebrate.\nThe game has a ton of action and sit on the edge of your seat adventure. It is hard to get wrapped up in a game, but this game has the minutes melting away. As my men start to bleed out, you hope they can crawl to you quick enough. The game is a constant battle.\nFor a dungeon crawl, this game has it all. It has a fun theme, lots of action, great components, and fun. Yes, it is actually fun to play.\nI highly recommend this game and it is a keeper.\nComponents:\nThe components in the box are the usual Fantasy Flight Games high quality components we are used to. The cards are going to last you for a long time and are easy to shuffle. The tiles and chits are the highest quality of cardboard.", "304" ], [ "The miniatures are fantastic. The player character minis are a tad hard to decipher from one another. My copy is painted, so that makes the job much easier.\nEverything in this box is beautiful. There is very little to complain about. The board is modular and grows as you explore. Based on the components alone, this is a must buy.\nRule Book:\nThe rule book is very good. I had zero problems with it. I have some minor complaints, but I will get to them. The book is comprised of a full color layout and gives many examples. The book provides instructions with pictures for nearly everything you do in the game. The book is organized well, but the large pictures sometimes interrupt the flow of the rules. This is a minor quibble.\nI wish gamers had been supplied with player aides for the game, but honestly despite the size of the rule book the rules are rather simple.\nI hold this rule book in the highest regard. You can read it once or twice and then jump into a game and start playing. An index would help the first few games flow better.\nFlow of the Game:\nI will not explain the rules, instead I hope to explain the flow of the game.\nYou are trying to accomplish a mission. Usually this means running through the map and killing a bad guy. Other times, it might be doubling back and getting to the \"finish line\".\nOn your turn, you draw 1-2 cards and then play a card. Cards allow you to move, attack, draw more cards, etc. The idea is these cards represent your health/stamina. If you run out of cards you then \"bleed out\". If you bleed out, you can no longer play cards nor draw cards until someone comes to your aid (discards a card in your same area).\nEach character has a special power which can be used whenever applicable.\nAfter playing a card, the bad guys then go. There is a deck of cards and you turn over the top card and do what it says.\nThese cards will move the bad guys, spawn new bad guys, and/or attack with the bad guys. You can play cards from your hand to attack them first or add to the number of your defense die (remember playing cards decreases your health/stamina so do so wisely). Everything is a hard choice.\nPlayer turn:\n1. Draw cards\n2. Play cards\n3.", "629" ], [ "Please check out my other reviews at:\nhttp://www.boardgamegeek.com/geeklist/145695/item/2728438#it...\nConclusion:\nAlien Uprising was a game I had never heard of when I bought it and sat down to play it. What intrigued me was the ability to play cooperatively and/or solo. Boy, was I in for a surprise! What I ended up finding was one of my favorite games I've ever played. I've played this game a lot since acquiring it and have loved every minute of it.\nFirst, this game is hard. It is hard to win and complex to understand. At its core, the game is easy (see below under Flow of the Game). It is all the little rules and a not perfect rule book that gets in the way. Honestly, like Arkham Horror, this is a game you can tweak the rules to in order to get the difficulty just right.\nThis game is dripping in theme. You can purchase miniatures and really make this game look great, but honestly the tiles are nearly perfect and work very well. I prefer the tiles at this point.\nThe game can be taught in minutes and you just figure out the smaller rules as the game progresses. While the game is a little complex, it is nothing that can't be taught in one siting. There have been quite a few questions online about the rules, but I found that if I just sat down and used common sense everything made sense.\nThis isn't a \"perfect\" Euro experience. Instead, we get a \"Castle Panic\" sort of game with a lot more rules, nastier alien/dinos, and a fantastic game. The game has interesting mechanics, most of which we have seen before, but puts it all in one very good package that will keep you wanting to play this game.\nI like the action die mechanic (think War of the Ring) and the unique characters who all play differently. Each character feels different and must be played to their strength if you want to beat this game. This might leave a feeling of doing the same thing over and over, but the different action dice will leave you with a lot of planning to do as a group.\nThere is luck in this game as you will roll dice to conquer the aliens and to accomplish things (ex: building shields). Yet, it all seems to balance out.\nI highly recommend this game. The biggest flaw might be the time required to play it. It can be a long game. It reminds me a lot of Arkham Horror, Castle Panic, and a good Ameritrash cooperative game.\nKeeper.\nComponents:\nThe bits are top notch and there are a lot in the box.", "386" ], [ "You get player mats for the characters and each character gets a unique of cards (they are small). All the tokens and chits are made of very thick cardboard. The characters are represented by tiles on the board (minis are included), but I felt the tiles worked great.\nI did have some issues with the board. I wish the green lines were brighter and more noticeable. It was hard to see it until I got used to the board. The board did have a nice theme to it and it looked great otherwise.\nThe aliens were represented by chits which worked as they needed to be two sided. I think a player aid with more information on it would have been helpful (a turn over view, alien powers, etc).\nAny complaints I have are nit picking and the components are really top notch. Great job!\nRule Book:\nThis a fairly complex game. Wait. No, it is not that complex. The game is pretty basic, but it has a few layers on top of it and a lot of moving parts. Think Arkham Horror (although this does not play like Arkham).\nThe rule could be organized better and perhaps be a little clearer. It helped that I had played Castle Panic (and Dead Panic) before so I was able to sort the game out. The book could be better. I also do not think it is as bad as some are making it out to be. I assume if I can figure the game out, it can't be all that bad. With that said, <PERSON> is not going to pull this off the shelf of Wal Mart and sit down and play this game.\nFlow of the Game:\nI am only explaining the flow of the game, not all the rules.\nThe board is made up of 4 sectors (each side of the board) and three levels inside those sectors. So, Sector 1 has A, B, C as does 2,3,4 (sectors). The aliens are trying to move towards the center of the board to get to your ship thus keeping you from leaving (think Castle Panic). You are a team of \"space marines\" trying to either wait for the rescue ship or to fix your ship so you can leave.", "386" ], [ "Please check out my other reviews at:\nhttp://www.boardgamegeek.com/geeklist/145695/item/3052753#it...\nConclusion:\nI am not a huge fan of Star Trek. I've never seen the show and I've only seen the new movies. Yet, the universe is very popular and it seems to be a very good show. I do like games with a known universe/property as it gives an easy reference point. This nails it with the theme. The game has so much theme and it comes shining through.\nThe ships look fantastic and really draw you into the game. It is fun to have all the ships from the shows bouncing around. In this game, it is the Federation, peace keepers, against the Klingons, warmongers. Both sides play differently and if you want to win you have to play to your strengths.\nDespite the cover of the box, this is not a combat heavy game. Instead, this is a game about exploration. The Klingons will want to fight much more than the Federation. Through out the game, you have missions you are trying to accomplish so it is not a last man standing sort of combat game.\nI like how the game plays differently for both sides. I like that it is not just about combat and rolling dice for results. The game has a lot of variety as the board is modular and different every time you set it up. The ships are different each game and there is a lot of different combinations. In addition, there are a ton of cards in the box and only a fraction are used in any single game.\nI can't explain how much I like this game. It doesn't fall into the same traps that a lot of two player games fall into (tug of war, etc). Instead, it provides a unique and fun atmosphere/game where you really feel like you are exploring the Star Trek Universe.\nKeeper.\nComponents:\nThe components are a mixed bag. There has been a lot of discussion about the components, but this is going to be just my opinion.\nI find some of the components to be very, very good. Others are dreadful.\nThe tiles that make up the modular board are paper thin. Possibly, the thinnest I've ever seen.", "304" ], [ "Paper thin. The art work on the tiles, the organization, the font are all great.\nThe cards, and there are a lot, are fine. I like the art work which is stills from the different shows.\nThe ships. The ships are the star of this show. There are so many ships from the shows. You get to mix and match which ones you use and it is so much fun. The \"hero clix\" ships are fantastic and I've had zero issues with them.\nThis is possibly the most polarizing components I've seen in any game. Some are top notch, others are bad for a print and play. I still recommend the game as you can work with what is in the box.\nRule Book:\nThe rule book is good, not great. You need to digest it before you get to the table. I wish the game had a player aid to use when playing and this is a huge miss.\nThe rules are longer than they need to be. This book needed an \"overview\" section of the rules and then a section that goes into more detail. This was missing and it was felt.\nOther than these few complaints, the rules are very good and you can be up and running after a single run through. There are some rules, like cloaking, that need a little more attention.\nFlow of the Game:\nI will not explain the rules of the game, instead I will attempt to explain the flow of the game.\nOn your turn, you will move around the galaxy. Each ship has a movement score. It is one movement point to move to an adjacent tile and all the tiles have a size on them (which represents how many movement points it requires to move through it).\nAdditionally, you can play command cards with can add crew to your ships or \"break the rules\" in general. This is not a new mechanic. If you use a card, you draw a card.\nYou can also take three actions. Actions can include: fighting enemy ships, scan nearby locations (peaking under a tile to see what is there), cloak your ships (two chits enter the board, one is a decoy), repair your ship, influence locations (build colonies, etc), complete missions.\nThese missions are the main way you score VP (10 VP wins the game). Some of these missions are secret and the majority are known by you and your opponent. As you accomplish these missions, you use an action to play the card or do a system check.\nAs a snapshot, you move around the board finding locations while accomplishing missions.", "629" ], [ "Please check out my other reviews at:\nhttp://www.boardgamegeek.com/geeklist/145695/item/2728438#it...\nConclusion:\nIf you have read these reviews before, you know that a good racing game is something I've been searching for. I've been harsh on the genre before and for good reason: most of the games have a lazy design and don't really make you feel like you are racing. Thunder Alley uses the drafting mechanic to near perfection. It brings NASCAR alive. You do not want to be off on your own in this game. You will move your own team and also the cars of other players due to the drafting mechanic. This is fantastic.\nThunder Alley looks great on the table despite all the cardboard. It is a brillant design. There is luck involved in which cards you get, but the game is more about using your cards to the best of your ability. The game removes dice from movement which is an intersting decision. So many racing games rely upon the dice movement. I find that after all this time it is a lazy mechanic to rely upon.\nThunder Alley is at its heart a very simple game. You play cards to move. You have just a few options in front of you with your card play. Yet, I feel like I get better at the game with more plays. The game doesn't take too long but it can be set up for a season or a longer play with more laps.\nThe truth is I just have fun playing this game. I get the feeling of speed. I try to attach to cars that haven't moved yet so I can move more than once. You don't want to get stuck in the back and not be connected and you don't want to be out front by yourself watching people pass you by. You will make alliances and break alliances throughout this game. There is a huge strategy in when to pit. Luck also exist in the random events that occur. This brings a different level to the game, but can be taken out if desired (although I've never done it).\nOverall, this is the best racing game on the market. I've yet to play Formula D(e) so I can't comment on that game yet. I love the drafting mechanic and how others have to pull (push) you along. Fun stuff!\nKeeper.\nComponents:\nThe components are your classic GMT components. You get a lot of little chits.", "885" ], [ "A lot. And some are very small. You can see the pictures here to see what they look like. The cars are double sided to easily see which ones have been moved. The player mats are not thick cardboard, but get the job done. The cards are high quality and I love the graphic design on them. Good job on the cards! This game pops in an interesting way. It isn't full of plastic, but it is easy to use the components and they still pop in a cardboard sort of way.\nThe game comes with 4 different maps which is a huge plus. This gives you different experiences.\nRule Book:\nThe rules are presented in classic GMT fashion. They are printed in \"war game\" fashion with the rules showcased like: 4.3 Losing a Car - see rule 2.54. The rules show a lot of black and white, but does have some pictures which are in full color. The rules are very wordy, but orgainzed well. Some of the rules are a little tricky at times. There is a misprint in regards to drafting, but it can be easily figured out. The rules include a description of every card for clearification. Overall, I'm happy with a rule set like this, but they can be very boring to read. It fees like you are reading instructions to an IKEA bookshelf.\nFlow of the Game:\nThe goal of the game is to get your cars across the finish line. You have a team of cars and you will get X VP based on what place each of your cars come in. Most VP wins the game.\nA turn in the game is represented by everyone moving all of the cars. This is in contrast to a single player round where the player will play a single card and move a single car as the \"first mover\".\nTurn:\n1. Draw Cards - You draw up to the number of cars you have left +1\n2. Perform Actions -\nA. Choose a car that has not yet moved\nB. Play a card and move the car (and perhaps others) per the directions on the card; this may put wear on the car per the usage on the card\n3. End of Turn -\nA. The car in the lead gets a turn leader marker which is worth VP at the end of the game\nB. Draw and perfrom an Event Card - This could be rain, a crash, nothing, some players get wear on their car, etc.", "629" ], [ "Please check out my other reviews at:\nhttp://www.boardgamegeek.com/geeklist/145695/item/2791786#it...\nConclusion:\nWhen this game is described to you (or at least to me) it sounds awful. You immediately think of Stratego and sigh. Why did they have to ruin a Lord of the Rings game. This is one of the most beloved books and movies of all time. Why oh why?\nYet, once you start playing the game you noticed that you judged it unfairly. That perhaps you judged the book by the cover and maybe you should not have. Why oh why did you judge this game so unfairly? You are actually having fun playing this. And this is Lord of the Rings: The Confrontation (Deluxe Edition).\nThe game is rather simple. The only complexity comes from learning the individual powers (listed on the cards and they are simple). Strategy comes next. I might get flamed for this, but, like a game of Chess, this game is a thinker.\nI haven't played the other versions, but this game is very nice to look at and I actually like the art work. The art work is unique and not from the movie license. The reason why this game has a following is the mix of easy to play with deep strategy; the game has risk that you can take and the payoff of a reward.\nOne player plays the light side and one the dark side. It is fun to try and get the fellowship into Mount Doom, while <PERSON> and his crew try to reach the Shire. The movement rules are easy to learn and the fighting is fun. The fighting does come down to card play, bidding, and a lot of bluffing. The fighting is not all luck; you have to watch what cards have been played and the better you know your opponent the more likely you are to win.\nEach character has a unique power that makes sense for the character. It is fun to play a game as the light side and the next game as the dark side. This game likely won't be the main event, but it is a game that you can start playing and find a night has \"wasted\" away and you had a ton of fun.\nThis is a keeper. I particularly like the Deluxe Edition as it has a variant and extra characters (not sure if other editions have these options also).", "366" ], [ "While not a favorite game of mine, it is a game that I can back to over and over. It plays two players (only!), but it plays fast. I highly recommend this game.\nComponents:\nThe components in the box are top notch. While this is not your usual tricked out edition, every thing in the box is very nicely down.\nI will start with the board. The board folds out and shows a map that is the setting of the Lord of the Rings. While not exactly accurate to the maps from the book, things are listed well enough for an abstract version of The Lord of the Rings. The colors used are muted to not take away from the action, but the different areas on the board are easy to see.\nThe bidding cards (for fighting) are good quality. They are large and the art work is great. The characters are represented by plastic holders that have the character cards inserted so you can only see it from one side (your opponent cannot see who is who). They are hard plastic and look very nice. The art work of all the characters are nice, but the font might be on the small side (but not hard to read). Everything in the box is good quality and you will be happy. Just don't expect the super primo pimped out edition.\nRule Book:\nThis is a Fantasy Flight Game (FFG) so you get the big oversized rule book. It is full color and full of pictures and examples. The art work on the front (same as on the box) is fantastic.\nI found this rule book to be wonderful and one of the best from FFG. It is simple to learn this game and the rule book is great at teaching it. There are a lot of examples in the book. There is the regular game and a variant that is explained (it uses another set of cards). The rule book explains all the cards and it is very helpful when you have questions.\nThere are also two Player Reference Sheets (one for each player) that describe all the cards and how they work.\nThe problem with the rule book and Player Reference Sheets (PRS) are they are so big. The PRS is way too big for to be useful on a table. Okay, it is very useful, but a smaller one would be useful and wouldn't take up so much valuable table room.\nFlow of the Game:\nEach player chooses a side: light or dark; good or bad.", "336" ], [ "Please check out my Geeklist at:\nhttps://boardgamegeek.com/geeklist/145695/purge-reviews-reco...\nMy video reviews can be found here:\nwww.youtube.com/purgereviewsboardgames\nConclusion:\nLong Shot was my favorite horse racing game and one of my go to party games. It accommodates a lot of players and everyone understands the concept of horse racing. It was and is an easy sell so when the Dice Version was released promising to be smaller, quicker, and just as good I have to admit I was intrigued.\nLong Shot the Dice Game improves on the original in almost every way. I will list a few pros and cons to this game:\n1. The game is short. It usually takes about 30 minutes to play the game. It doesn't over stay its welcome and plays in about the perfect amount of time. The original was more like 60-90 minutes so this is an improvement but you will need another game to play on the same night where the original was a game to center the night around.\n2. While I really like the look of the game, the original is larger and fills up a table better. A lot of people are going to like the compact nature of this game, but it is a tad small for 8 people. I may be in the minority, but I would like a Jumbo version of this game. Larger cards, bigger horses, etc.\n3. The game is easy to teach. You roll some dice and everything works off the dice. People understand instantly the roll and move mechanic and betting on the horses. It takes just a couple of minutes to teach the game and most people will be able to play without any questions.\n4. The game is full of luck. That's the game. It is all about profiting off that luck and pressing your luck to generate more and more cash. The horses are going to move on their own, but you can start to add marks to the horse to influence the horses you want to move. I guess that is the best way to comment on it: you are trying to influence the horses and the outcome. Some people are going to like this and others hate it.\nOverall, I have to admit I love this game.", "581" ], [ "I've been playing the solo game over and over trying to beat that <PERSON> character. I've played this with a lot of different player counts and it does a good job of keeping you invested when it isn't your turn. The game mitigates this by letting you take an action on other players turns. That's a great fix.\nI can highly recommend this game for people who want a horse racing game and like to have fun. This is a dice rolling, horse betting, take out your opponents good time and one I'm willing to play anytime.\nKeeper.\nComponents:\nThe components are top notch for a roll and write and a light filler. The horses are silk screened on both sides and fit the smaller board perfectly. The dice are a tad on the cheaper side, but they do get the job done. You get plenty of dry erase markers which are pretty standard for this sort of game. Everything has a great look to it and I like the choice of sillier art work. The package is very, very good for the price point.\nRule Book:\nThe rule book takes about 15 minutes to read. The rules are full of color and has plenty of pictures and examples. This is a very easy to read rule book and everything seems to flow perfectly as you read through the rules. The book is easy to digest and to use as a reference while playing.\nFlow of the Game:\nThis is a horse racing game. The race is over when 3 horses finish the race. Each horses is awarded a place (1st, 2nd, 3rd).\nPlayer Turn:\n1. Roll both dice\n2. One die is the horse to move; the other die is how many spaces to move (1-3 spaces); then move all the horses listed on the card 1 space only\n3. Then, each player takes an action in turn order based on the die identifying the horse:\na. Bet on the horse rolled\nb. There is a chart where if you finish a line you get money, free bets, move the horses, etc\nc. Add a helmet - this allows you to bet after the horse crosses the no more bets line\nd. Add a jersey - this allows you to mark for another horse to move when this horse is activated\ne. Purchase a horse (each horse as a power that is activated when the number is rolled)\nYou score points if a horse you own places, each helmet/jersey combo is worth 5 points, gain money for bets plus any money left over.\nMost points/money is the winner of the game.\nShould I buy this game?", "629" ], [ "Designers: <PERSON> and <PERSON>\nPublisher: Z-Man Games\nPlayers: 2\nLength: 30-45 minutes\nAge: 13+\nAkrotiriis a game about excavating ancient Greek temples around the island of Thera. It is a tile placement game that is a quite a bit more brain burning that I expected. The object of the game is to score the most victory points by excavating temples (completing map cards) and completing hidden goals.\nComponents\nI would say the components are average. The wooden player boats, temples, and resource cubes are standard quality. I had two cubes (a red and gray) that were stuck together when I opened the box. Separating them caused a big chunk to come out of one of the cubes. Not a huge deal, just a pain. I guess the paint wasn't completely dry when the cubes were put into the bag. The player and resource boards are rather thin and flimsy. Not a big issue, but they are already showing some wear on the corners. The tiles on the other hand are a bit thicker and will probably hold up well. The cards are of average quality. I sleeve, so thinner cards don't bother me. The money is cardboard in denominations of 1 and 5 drachmas and I find the 1 coins to be rather small. People with larger fingers might have some trouble with these smaller pieces.", "336" ], [ "The art is good and the iconography is clear on the cards, the tiles, and the player boards. The rulebook is well done and follows the flow of play well. The goal cards are all explained in the appendix at the back of the rulebook which is something all rulebooks should have.\nGameplay\nThe game is played over several turns with each player placing a tile, seeding the tile with 2 resources (one mandatory type, one optional), and then performing actions. I won't go into all the rules or how the game is played, but know that the tile placement is really the heart of the game. Paying attention to what your map cards require, watching what your opponent is doing to take advantage of his tile placements, and working the resource market to make enough money to excavate are really key. Maintaining shipping lanes to minimize the number of move actions required is also important.\nWhat do I think?\nI have played this twice and really enjoy the game. It starts out a bit slow and feels like it might be longer than expected, but quickly ramps up and you find yourself placing temples (and getting more actions) almost every turn in the later part of the game. As I mentioned before, it is a bit more brain burning than I expected due to the spatial nature of the map cards. You want to place your tiles in such a way to maximize the benefit of your map cards, but doing that sometimes blocks your path to the island where you need to excavate. It took a few rounds to get my head around the map cards, but if you take them for exactly what they are thematically, it really makes sense. I like to think of the map cards as the old pirate maps you see in the movies. \"X\" marks the spot. The \"X\" was west of the volcano, south of the lake, and east of the mountains. In this case, the \"X\" is your excavation spot where you can place your temple.\nIf you enjoy 2-player games with tile placement, hidden goals, some pick-up and deliver elements, and spatial awareness, Akrotiri might be for you. I give it a strong 7.5 out of 10.", "349" ] ]

[ 9462, 11231, 87, 2613, 10228, 3998, 5006, 9090, 9204, 4437, 2962, 11361, 127, 9629, 1279, 1130, 5611, 4851, 107, 10154, 11378, 9550, 5348, 5923, 8193, 527, 6351, 3635, 7271, 7307, 3979, 4707, 1812, 7159, 6355, 10402, 6582, 6678, 10378, 7571, 2463, 1291, 3300, 4442, 8990, 5767, 391, 7680, 915, 4933, 7425, 462, 7710, 4932, 7683, 528, 9398, 2781, 3773, 1314, 5136, 2022, 635, 416, 3931, 6611, 1215, 7566, 10113, 5999 ]

[ [ "Q1 Is $F=\\frac{d(mv)}{dt} just a definition or is there something \"more\" behind the formula for force?\n$\\vec{p} = m\\vec{v}$ is a definition! $\\vec{F} = m\\vec{a}$ is not! Pratically speaking, you can measure both Force (using an elastic material and its deformation) and acceleration (double derivative of space respect to time), <PERSON> discovered they're proportional so, since they're definite indipendently, $\\vec{F} = m\\vec{a}$ is the relation between $\\vec{F}$ and $\\vec{a}$ not the definition of force! You can't measure momentum, so you'll need to define it! The definition is $\\vec{p} = m\\vec{v}$ and the reasons are perfectly explained on <PERSON> books.\n$$\\vec{F} = m\\vec{a} = m\\frac{d\\vec{v}}{dt} = \\frac{d(m\\vec{v})}{dt}$$\nQ2 Is W=∫F⃗ ⋅ds⃗ just a definition or is there something more behind? I mean, can you derive the formula for work not by taking the formula for the kinetic energy as given.\n$$W = \\int \\vec{F} \\cdot d\\vec{s}$$ is the definition of work done by a force $\\vec{F}$ along a path, you do not need kinetic energy to define work. Energy is the possible work doable by a moving body.\nQ3 How to derive the formula for the kinetic energy and work only form the conservation of momentum Σmivi→=const.?\nYou know that $\\vec{F} = \\frac{d(m\\vec{v})}{dt} = \\frac{d\\vec{p}}{dt}$ but since $\\vec{p}$ is costant, is derivative will be zero.", "512" ], [ "In case it is moving with costant speed $\\vec{v_0}$. Now, imagine a costant force applied to the mass, you'll have that $v^2 - v_{0}^2 = 2as$ (from cinematics) $Fs = W = \\Delta E$, $mas = W \\Rightarrow$ $$v^2 - v_0^2 = 2W/m$$ $$W = \\frac{1}{2}mv^2 - \\frac{1}{2}mv_0^2$$ The applied force is going to stop the mass, so the mass reacts with an opposite force, and since energy is the possible work done by the moving mass. Since it is opposed and $v= 0$ we obtain: $$ W = \\frac{1}{2}mv_0^2$$ Energy depends only on the initial velocity because momentum (before the costant force applies) is conservating.", "512" ], [ "The force of gravity will simply move the equilibrium point, being a costant force. So if $l_0$ is the initial lenght of the spring, the applying the orizontal component of the force $Mg\\sin \\theta$, you'll get the new lenght in equilibrium that is (<PERSON>'s Law) $$ \\vec{F} = -k\\vec{(x - x_0)} \\Rightarrow x = F/k + x_0$$ $$x_1 = Mg\\sin \\theta / k + x_0$$ Since gravity is costant over time, any displacement applied to the string will act as if the initial lenght of the string is $x_1$, not $x_0$. So the amplitude of harmonic oscillation won't change, but you must consider the amplitude relative to $x_1$, not $x_0$.", "766" ], [ "You have to put the $0$ in your ruler on $x_1$, rather than $x_0$.\nYou can prove this statement solving the differential equation: $$F = ma = m\\frac{d^2x}{dt^2} = -k(x - x_0) + Mg\\sin \\theta $$ $$ m\\frac{d^2x}{dt^2} +kx = kx_0 + Mg\\sin \\theta $$ there is no $x$ in the $Mg\\sin \\theta$ so you can simply consider $$kx_0 + Mg\\sin \\theta$$ as a costant term $kx_1$ so you'll get $$ \\frac{d^2x}{dt^2} + \\frac{k}{m}x = \\frac{k}{m}x_1 $$ the amplitude is given solving the differential equation http://en.wikipedia.org/wiki/Ordinary_differential_equation it doesn't depend on $x_0$ or $x_1$.\nConsidering the problem using conservation of energy, you'll get: Let's say that $h_0$ is the height relative to $x_0$ so $h = x\\cos \\theta $ energy at $x_0$ will be $$ mgh_0 + \\frac{1}{2}m\\upsilon^2 + \\frac{1}{2}k(x_0 - x_0)^2$$ energy at a displacement $\\Delta x$ from $x_0$ $$mgh_0 + mg\\Delta h + \\frac{1}{2}m\\upsilon^2 + \\frac{1}{2}k(\\Delta x)^2$$ every force is conservative so $$ mgh_0 + \\frac{1}{2}m\\upsilon_0^2 + \\frac{1}{2}k(x_0 - x_0)^2 = mgh_0 + mg\\Delta h + \\frac{1}{2}m\\upsilon_1^2 + \\frac{1}{2}k(\\Delta x)^2$$ if the cart is release with $\\upsilon_1 = 0$ $$ \\frac{1}{2}m\\upsilon_0^2 = mg\\Delta x \\cos \\theta + \\frac{1}{2}k(\\Delta x)^2$$ the speed at $x_0$ depends only from the inital displacement $\\Delta x$ and not from $x_0$ or $x_1$ absolutely.\nTheoretically the amplitude won't change, but since there are other factors as friction, measures aren't perfectly matching to theory. The inclined plane present less friction rather than an horizontal plane due to the vertical component of the weight of the cart. So taking friction into account total energy will decrease while the cart is moving so, it will decrease the amplitude of motion.\nHope this help!", "526" ], [ "You forgot one term when you derived $\\left(\\vec{v_{B/ A}}\\right){\\omega_0}$ with respect to the inertial reference frame. The correct would be: $$\\frac{d}{dt}\\left(\\vec{v{B/ A}}\\right){\\omega_0}=\\left(\\vec{a{B/A}}\\right){\\omega_0}+\\omega{/0}\\times\\left(\\vec{v_{B/A}}\\right){\\omega_0}$$ in same way as you did for deriving $\\vec{r{B/A}}$.\nAdding something from the comments:\nI will call $\\mathbf{i},\\mathbf{j}$ the vectors of the intertial reference frame and $\\hat{\\mathbf{i}},\\hat{\\mathbf{j}}$ the ones of the moving one\n(and I'm going to be a bit loose with the notation)\nBasically, for every vector you can imagine you have that: $$\\mathbf{r}B = \\mathbf{r}_A+\\left(\\mathbf{r}_B-\\mathbf{r}_A\\right)$$ or using your notation: $$\\mathbf{r}_B = \\mathbf{r}_A+\\mathbf{r}{B/A}$$\nIn principle you could derive $\\mathbf{r}A$ and $\\mathbf{r}{B/A}$ in the same way, but probably $\\mathbf{r}_{B/A}$ can be written much more easy in an basis moving with A, i.e. $\\hat{\\mathbf{i}},\\hat{\\mathbf{j}}$.\nSo we have that:\n$$\\mathbf{r}A=r{Ax}(t)\\mathbf{i}+r_{Ay}(t)\\mathbf{j}$$ and its derivative $$\\frac{d\\mathbf{r}A}{dt}=v{Ax}(t)\\mathbf{i}+v_{Ay}(t)\\mathbf{j}=\\mathbf{v}_{A/o}$$\nHowever, for the case of $\\mathbf{r}{B/A}$ you have that $$\\mathbf{r}{B/A}=r_{B/Ax}(t)\\hat{\\mathbf{i}}(t)+r_{B/Ay}(t)\\hat{\\mathbf{j}}(t)$$ You see the difference?", "804" ], [ "I've made a small illustration depicting the key idea. If this is in coherence with what you've asked, we could summarize some important points about the case.\nTotal energy of the Earth and Bar Magnet system is given by the equation: $KE + PE = \\frac{1}{2}mv^{2} + \\frac{GMm}{R}$\nWhile PE is there for both Earth and magnet system (combined), KE is available for the magnet to spend on oscillation. If, while oscillating, it spends this KE by transforming it in to thermal energy in the resistor-inductor circuit, KE decreases slowly and becomes zero. $KE + PE = 0 + \\frac{GMm}{R}$ ie, the oscillation seize to exist.\nAn easy way to look at it would be to consider change in KE. We will start with the magnetic pendulum:\nComponent of angular acceleration = $\\alpha =\\frac{-Lmg\\ sin(\\theta)cos(\\theta)}{I}$\nThis clearly has its peak values at 45 degree amplitudes.", "780" ], [ "Now, component force due to this restoring torque is give by,\n$F =\\frac{-L^{2}m^{2}g\\ sin(\\theta)cos(\\theta)}{I}$\nFrom this pushing or pulling force we can derive the power and thereby energy:\n$P=Fv$\n$\\frac{dE}{dt} = Fv = \\frac{-L^{2}m^{2}gv}{I}sin(\\theta)cos(\\theta)$\nOn integrating,\n$\\int dE = \\int \\frac{-L^{2}m^{2}gv}{I}sin(\\theta)cos(\\theta)\\ dt$\n$\\int_{0}^{\\frac{T}{2}}dE = k\\int_{0}^{\\frac{T}{2}} vsin(\\theta)cos(\\theta)\\ dt$\nThis gives the push energy in one single push (half the oscillation period).\nNow the energy burned by the resistor is given by:\n$dE = Pdt$\n$\\int_{0}^{\\frac{T}{2}}dE = \\int_{0}^{\\frac{T}{2}}Pdt$\n$\\int_{0}^{\\frac{T}{2}}dE = \\int_{0}^{\\frac{T}{2}}I^{2}Rdt$\nCurrent in the LR circuit is\n$I = \\frac{V}{R}\\left (1-e^{\\frac{-Rt}{L}} \\right )$\nSubstituting for current,\n$\\int_{0}^{\\frac{T}{2}}dE = \\int_{0}^{\\frac{T}{2}} V\\left (1-e^{\\frac{-Rt}{L}} \\right )^{2}dt $\nThus the change in energy for a half cycle is\n$\\Delta E_{\\frac{T}{2}} = k\\int_{0}^{\\frac{T}{2}} vsin(\\theta)cos(\\theta)\\ dt - \\int_{0}^{\\frac{T}{2}} V\\left (1-e^{\\frac{-Rt}{L}} \\right )^{2}dt$\nThis is how the RHS dampens energy change. The resistance in the second integral dominates in each integration. If it wasn't there, The remaining emf/potential term will cancel itself in a full cycle integration. Thus, there would not be an energy change. This isn't surprising because inductor can give back the magnetic force in each half cycle with the same magnitude. I hope this will make it more clear since my previous attempt was somewhat dubious.", "37" ], [ "Why didn't he consider the centripetal force as a force acting on that object.\nBecause Centripetal force is not a force acting on the body. The Centripetal force is not necessarily a unique force in its own right. As an answer pointed out, The \"centripetal force\" is simply defined as the net force acting towards the centre.\nIf there were some more forces acting in the radial direction (for example, if your car was tied with a rope to a tree at the centre of the circle, there would be an additional force of Tension towards the centre) then the sum of the forces would be equal to Tension + the Normal reaction component. This sum would then be considered the centripetal force.\nHere is another way to thing of the scenario : Write the <PERSON>'s law equation for the radial direction without thinking anything about being on a circular trajectory. Don't think anything about centripetal forces for a moment.", "766" ], [ "If were on any other ordinary track, the only force on the car would be $N\\sin(\\phi)$ which then by <PERSON>'s law is equal to $ma$. $$Nsin(\\phi) = ma$$\nNow, because you are moving in a circular path, the \"a\" in the equation must be towards the centre of the circle and its magnitude is a function of the linear velocity at which you are moving in the circular path (specifically it is $\\frac{|v(t)|^2}{r}$ but in your case, v is constant). Now, this is something you have to accept, in circular motion, there must be an acceleration pointing to the centre with the magnitude mentioned above, otherwise the motion would not be circular anymore. Plug this into the equation and you simply get the result as : $$N\\sin(\\phi) = \\frac{mv^2}{r}$$ This pretty much what the other answers said, that the sum of all forces towards the centre (there is only 1 in your case) is the centripetal force. I have taken the opposite sign convention but it doesn't affect the final result.\nTo answer one of your side questions, if $\\phi = 0$, essentially when the road is unbanked and frictionless (as per the diagram), you would never be able to make a turn (In reality, there is always friction to provide the necessary force towards the centre).\nHope this helped.", "544" ], [ "Columb law (vetorial) $$ \\vec{E}(x,y,z) = \\frac{e \\vec{r}}{4 \\pi \\epsilon_0 r^3}, $$\nBiot-Savart (vectorial + some calculus simplification from $ c = \\frac{1}{\\sqrt{\\epsilon \\mu}}$) $$ \\vec{B}(x,y,z) = \\frac{\\mu_0 e (\\vec{v} \\times \\vec{r}) }{4 \\pi r^3} =\n\\frac{(\\vec{v} \\times \\vec{r}) q}{c^2 (4 \\pi \\epsilon_0 r^3)} = \\frac{\\vec{v} \\times \\vec{E}}{c^2} $$\nThe correct way to treat electromagnetism interaction in relativity is to use electromagnetic tensor $F^{\\mu\\nu}$\n$$ F^\\mu_\\nu = \\left( \\begin{matrix} 0 & -E_x/c & -E_y/c & -E_z/c \\ -E_x/c & 0 & -B_z & B_y \\ -E_y/c & B_z & 0 & -B_x \\ -E_z/c & -B_y & B_x & 0 \\ \\end{matrix} \\right) , $$\nFour-velocity vector $$ \\gamma = \\frac{1}{\\sqrt{1 - \\frac{v^2}{c^2}}}, d\\tau = \\frac{dt}{\\gamma}$$\n$$ U^\\mu = \\left ( \\begin{matrix} \\gamma c \\ \\gamma v_x \\ \\gamma v_y \\ \\gamma v_z \\ \\end{matrix}\\right ) , $$\nRelativistic \"force\" law\n$$ \\frac{d(m_{0}U^\\mu)}{d\\tau} = - e F^\\mu_\\nu U^\\nu $$\nSome notations $$ \\beta_x = \\frac{v_x}{c} , \\beta_x = \\frac{v_y}{c} , \\beta_z = \\frac{v_z}{c} , \\beta = \\frac{v}{c}, v = \\sqrt{v_x^2 + v_y^2 + v_z^2} $$\nLorentz Boost in arbitrary direction: $$ \\Lambda^\\mu_\\nu(v) = \\left ( \\begin{matrix} \\gamma & -\\beta_x\\gamma & -\\beta_y\\gamma & -\\beta_z\\gamma \\ -\\beta_x\\gamma & 1 + (\\gamma - 1)\\beta_x^2/\\beta^2 & (\\gamma - 1)\\beta_x\\beta_y/\\beta^2 & (\\gamma - 1)\\beta_x\\beta_z/\\beta^2 \\ -\\beta_y\\gamma & (\\gamma - 1)\\beta_y\\beta_z/\\beta^2 & 1 + (\\gamma - 1)\\beta_y^2/\\beta^2 & (\\gamma - 1)\\beta_y\\beta_z/\\beta^2 \\ -\\beta_z\\gamma & (\\gamma - 1)\\beta_z\\beta_x/\\beta^2 & (\\gamma - 1)\\beta_z\\beta_y/\\beta^2 & 1 + (\\gamma - 1)\\beta_z^2/\\beta^2 \\ \\end{matrix} \\right ) $$ Lowering + uppering indexes $$ \\Lambda_\\mu^\\nu(v) = \\eta_{\\mu\\alpha}\\eta^{\\nu\\beta} \\Lambda^\\alpha_\\beta(v) $$ $$ \\Lambda_\\mu^\\nu(v) = \\left ( \\begin{matrix} \\gamma & \\beta_x\\gamma & \\beta_y\\gamma & \\beta_z\\gamma \\ \\beta_x\\gamma & 1 + (\\gamma - 1)\\beta_x^2/\\beta^2 & (\\gamma - 1)\\beta_x\\beta_y/\\beta^2 & (\\gamma - 1)\\beta_x\\beta_z/\\beta^2 \\ \\beta_y\\gamma & (\\gamma - 1)\\beta_y\\beta_z/\\beta", "804" ], [ "Goldstein Classical Mechanics exercise 5.17 (3ed) conceptual\nI am having difficulty understanding a concept in the \"Heavy symmetric top\" type of problems. I will include all of my efforts as to hopefully have someone easily point out what it is that I'm missing. The question reads:\nA uniform right circular cone of height $h$, half-angle $\\alpha$ and density $\\rho$ rolls on it's side without slipping on a uniform horizontal plane in such a manner that it returns to it's original position in a time $\\tau$ . Find expressions for the kinetic energy and the components of the angular momentum of the cone.\nI begin by finding the volume (since I memorize no such things) and decide on the obvious choice of cylindrical coordinates.", "15" ], [ "My mass will then be $$\\rho\\int_0^h \\int_0^{2\\pi} \\int_0^{z \\tan{\\left(\\alpha\\right)}}r \\, \\mathrm{d}r \\, \\mathrm{d}\\theta \\, \\mathrm{d}z = \\frac{\\pi \\rho R^2h}{3} $$ then while I'm at it I likewise find the center of mass (in the $z$) $$\\frac{1}{V}\\int_0^h \\int_0^{2\\pi} \\int_0^{z \\tan{\\left(\\alpha\\right)}}zr \\, \\mathrm{d}r \\, \\mathrm{d}\\theta \\, \\mathrm{d}z = \\frac{3h}{4} $$ moving onto the moments for the inertia tensor, I use$$ I_{ij} = \\int_V\\rho \\left(\\delta_{ij} \\Sigma_k x_k - x_i x_j\\right) \\, \\mathrm{d}V $$ and find that $\\bf{I}$ is already diagonal, I get elements $I_1 = I_2 = \\frac{3M}{20}\\left(R^2+4h^2\\right)$; and $I_3 =\\frac{3M}{20}\\left(2R^2\\right)$ so that the inertia tensor about the apex at the origin of the coordinate system is given by $$ \\bf{I} = \\begin{bmatrix} \\frac{3M}{20}\\left(R^2+4h^2\\right) & 0 & 0 \\ 0 & \\frac{3M}{20}\\left(R^2+4h^2\\right) & 0 \\ 0 & 0 & \\frac{3M}{20}\\left(2R^2\\right)\\end{bmatrix} $$\nnow in the event I should need $\\bf{I}{CM}$ I also get that out of the way and find that using the parallel axis theorem, $ I{1_{CM}} = I_{2_{CM}} = \\frac{3M}{20}(R^2+\\frac{h^2}{4}) = \\frac{3M}{80}\\left(4R^2+h^2\\right)$; and $ I_{3_{CM}} =\\frac{3M}{80}\\left(8R^2\\right)$ so that $$ \\bf{I}_{CM} = \\begin{bmatrix} \\frac{3M}{80}\\left(4R^2+h^2\\right) & 0 & 0 \\ 0 & \\frac{3M}{80}\\left(4R^2+h^2\\right) & 0 \\ 0 & 0 & \\frac{3M}{80}\\left(8R^2\\right)\\end{bmatrix} $$\ngreat. So it seems that I may use either the inertial frame OR the body frame, however this is where I'm getting confused. As I understand it, if I change my coordinates to the center of mass body coordinates, I will not need to consider the translational kinetic energy of the center of mass. But can I even do this here? In any event I find $v_{CM} = \\frac{3h}{4} \\cos(\\alpha)\\dot{\\phi}$ where $\\phi$ is the azimuthal angle about the fixed inertial $z$-axis, and I can find various relations for this based on the no-slipping condition though its not clear which I should want. Now that I have gotten most of the legwork done, I want to write my expression for the kinetic energy.", "402" ], [ "Lagrangian equations of motion for ball rolling on turntable\nThe equations governing the motion of a ball of mass m, radius R rolling on a table rotating at constant angular velocity $ \\Omega $ which are derived using <PERSON>'s laws are: (I present these for comparison) \\begin{align} (I+mR^2) \\dot{\\omega}_x &= (I+2mR^2)\\Omega \\omega_y-mR \\Omega^2y \\ (I+mR^2) \\dot{\\omega}_y &= -(I+2mR^2)\\Omega \\omega_x + mR \\Omega^2 x \\ \\dot{x} &= R \\omega_y \\ \\dot{y} &= -R \\omega_x \\end{align} Where $x,y,\\omega_x,\\omega_y$ are absolute values measured in the rotating frame ($x,y$ being positions and $\\omega_x,\\omega_y$ angular velocities of the ball). To express the position, velocity, etc in the inertial $XYZ$ frame we can perform a change of variables: \\begin{align} X=x \\cos \\theta - y \\sin \\theta \\ Y=x \\sin \\theta + y \\cos \\theta \\end{align} The equations written above are correct as far as I know. Now I've tried to derive these equations using the Lagrangian approach, but my equations differ slightly from the above.", "101" ], [ "I'll share my work here:\nWe start with the standard formulation of the Lagrangian equations of motion: $$\\frac{d}{dt} \\left( \\frac{\\partial L}{\\partial \\dot{q_i}} \\right) - \\frac{\\partial L}{\\partial q_i}=Q_i$$ For this system, there are no non-conservative forces doing work at any time so $Q_i=0$ (Assuming no-slip here). Now the kinetic energy of the system is: $$T=\\frac{1}{2}m \\| v \\| ^2 + \\frac{1}{2} I \\| \\omega \\|^2 $$ Where $v$,$\\omega$ are the absolute linear and angular velocities of the ball, $I$ is the moment of inertia of the center of mass. I'll proceed in the rotating frame basis $xyz$, where the position $r$ of the ball is given by $$\\vec{r}=x \\hat{i} + y \\hat{j}$$ Using velocity kinematics in rotating frames, the absolute velocity of the ball is given by: $$\\vec{v}=\\vec{\\Omega} \\times \\vec{r} + \\vec{v}{xyz}$$ Where $\\vec{v}{xyz}$ is the velocity of the ball in the rotating frame: $$\\vec{v}{xyz} = \\dot{x} \\hat{i} + \\dot{y} \\hat{j}$$ So the absolute velocity $\\vec{v}$ after expanding gives: $$\\vec{v} = (\\dot{x}-\\Omega y) \\hat{i} + (\\dot{y} +\\Omega x) \\hat{j} $$ It follows from taking the magnitude of the absolute velocity: $$\\| v \\|^2 = (\\dot{x}-\\Omega y)^2 + (\\dot{y}+\\Omega x)^2$$ The first unknown term in the Lagrangian equations of motion.", "101" ] ]

[ 6903, 6399, 7635, 11382, 4818, 7662, 1086, 7964, 4163, 5355, 5312, 4625, 3160, 1924, 208, 8358, 1474, 2115, 3995, 4654, 4049, 5702, 2125, 6407, 7335, 8623, 6257, 6731, 10452, 786, 2210, 6766, 6686, 10115, 10386, 315, 4390, 6418, 4062, 460, 6937, 8614, 4712, 4014, 199, 4376, 11224, 2087, 5384, 3407, 7397, 2907, 10674, 9580, 469, 10476, 3136, 2272, 2510, 9370, 10628, 6157, 3070, 11264, 10177, 431, 4560, 2348, 10497, 2395 ]

[ [ "First it will be important to consider the term 'relativistic speed'. If by that you mean something like 0.1c, it will only change the colour of the stars as you mentioned in the bounty description. However, if it means something with higher Lorentz Gammas (like 0.9c or 0.99c), all other relativistic effects come into play. There's relativistic beaming and aberration combined, which means that all the light that you receive from systems with respect to which you're moving at relativistic speeds will only be received in small beams towards the direction you're moving in and those will be strongly blueshifted and intensified. Watch this animated video for an illustrated view of what I mean - https://www.youtube.com/watch?v=JQnHTKZBTI4. (It's not a high quality video, but it is very effective in demonstrating what I just wrote.)\nSo, in effect, you will possibly see only three major sources of light in the sky:\n1. The parent planet\n2. The parent star\n3. The bright patch of the sky in the direction of motion, highly blueshifted, with brightness dependent on your speed\nTheir relative brightnesses will depend on:\n1. distance to parent star\n2. distance to parent planet\n3.", "562" ], [ "albedo of the parent planet\n4. speed of motion through the ism\nFor a day and night cycle:\n* The parent planet will obviously be at the zenith the whole time (or fixed location in the sky if you're at a different location).\n* The parent star will appear to move around the sky with the same period as the revolution period of the moon - say a few days at the most (will be fairly small as compared to the 12 year revolution period of the planet, so you can ignore 'synodic' effects to the first order for a single day/night cycle).\n* The sky will also move with roughly the same period as the sun, ignoring synodic effects.\nWinds will be very complexly affected by the three sources (since heating due to radiation affects winds). There will also be tidal effects due to the parent planet which also play a role in the winds (similar to how tides work on the earth). So, you will have to take into account heating from the star, heating from the planet (which is constant due to tidal locking), tidal effects of the planet (again constant) and heating from the sky. Now the radiation from the sky can also act in a weird way, since blueshifting can give rise to strong emissions in UV, X-ray and Gamma ray photons, plus relativistic cosmic rays (everything you encounter will be in the form of cosmic rays due to the relativistic speed of your motion). These can ionize the atmosphere, heat it, cause there to be particle showers and aurorae, which can all affect wind patterns in complex ways, which I cannot exactly say much about, given my limited knowledge in atmospheric sciences.\nAs I mentioned above, yes, all interactions will be relativistic and will be similar to cosmic ray bombardment onto the moon you live on. Things will get nasty and you'll be having geomagnetic storms all the time. Satellite communications will probably never work. Expect these particles to arrive in the previously mentioned bright region of the sky due to aberration still applying to this case. You will see similar aurora like regions on the parent planet (http://www.spacetelescope.org/static/archives/postcards/screen/hst_postcard_0008.jpg), and the star will probably not be affected that much.\nOh and by the way, due to the antimatter nature of your system and the matter nature of the ism, the atmosphere would thin over time, and later these antimatter cosmic rays will start bombarding the moon. So if you stay in the ism for long enough, living on the moon will be difficult. Also, I am assuming that life evolved on your moon in an antimatter ISM and you have entered the matter ism only recently, as otherwise, the moon won't be stable for long enough for life (intelligent life) to evolve.\nI will try to see if I can think of some other effects, but for now, I guess this will do?!", "921" ], [ "To start with, a (non rotating) black hole and a star of the same mass creates the same gravitational potential when you are far away enough. Since we observe planets at $0.05\\mathrm{AU}$ around stars of about the same mass as the sun, I think you can expect planets in this region around a similar mass black hole, according to stability criterion. Moreover, the smallest black holes you can physically create have masses of about $3-4 M_\\odot$.\nThere are multiple issues here though. First is how do you physically bring the planet that close to the black hole? I see two possibilities. Either the planet formed directly in the accretion disk of the black hole, and staid there, or the planet formed further away (say around the binary star system) and was captured by the black hole. If you assume that at $0.05\\mathrm{AU}$, the accretion disk of the black hole is not that different than the accretion disk around a protostar at early ages, then you can maybe create a planet there (I can think of a few scenario that would prevent it, but it would require a more important study). If the planet formed further away in the disk or in the binary system, it is possible to make it migrate inward.", "788" ], [ "This is actually called ex-situ formation in planetary systems.\nIf you imagine that the planet is tidally locked (you can try fiddling around with the formula $t_{\\text{lock}} \\approx \\frac{\\omega a^6 I Q}{3 G m_p^2 k_2 R^5}$ from wikipedia that gives the timescale for the planet to become tidally locked to get an estimate of how long it would take) and that there is no accretion disk anymore, I guess you could manage to make the system stable.\nThe final question is then to get the whole system stable on a large. Even though it may extremely unlikely, I think there has to be some stable orbits in the system using 3 body resonance, but this is not my field of expertise. having one or two stars is not making a huge difference, between the flux received from them and the gravitational pull are both in $1/r^2$, so that two stars at 1.4AU give the same flux and the same mean gravitational pull than one star at 1AU. The only difference is in the stability of the system.\nTo conclude, I guess that the system is very unlikely to exist. Yet if you manage to find a planet there, you'd require to have life:\n1. the accretion disk of the black hole has to be cleared\n2. the planet should be tidally locked to the black hole to be protected from the radiations\n3. the planet should be trapped in a very unlikely stable orbit so that it doesn't travel around in the system AND it has time to get tidally locked to the black hole", "788" ], [ "We don't know and you can make up the effect you want. The answer given above correctly sums up our current understanding of black holes and gravity. However, currently we can't reconcile our understanding of gravity (which explains black holes) with our understanding of quantum mechanics (which explains mater/antimatter interaction). In other words, \"nothing will happen\" ist not something we know but something we'd need to test in an experiment.\nIf you want a spectacular effect, you can make one up: During matter/antimatter annihilation, the mass/energy stops to have gravity for short moments (due to quatnum gravity effects we have not been able to observe yet, because they are to weak when we do these experiments with single atoms in a collider). This allows some mass and or radiation to escape (either in direction with the spin of the BH, or as a jet along the axis of rotation). Also the on/off sends strong gravitational waves.", "343" ], [ "Some of the emitted matter/energy lumps may be dense enough to form black holes themselves, they may loose momentum when interacting with the accretion disks and fall back into the large BH ...\nThe shape will be weird - wikipedia has this to say about a black hole merger: \"As two black holes approach each other, a ‘duckbill’ shape protrudes from each of the two event horizons towards the other one. This protrusion extends longer and narrower until it meets the protrusion from the other black hole. At this point in time the event horizon has a very narrow X-shape at the meeting point. The protrusions are drawn out into a thin thread. The meeting point expands to a roughly cylindrical connection called a bridge.\"\nOne question that a reader with a good grasp of physiscs will have is when this cataclysm will happen - I think our best guess according to current physics is that time will stop inside the event horizon due to gravitationl time dilation. Short 'hiccups' in gravity will also stop this dilation.\nFor story purposes it would be a bad idea if the affair becomes a completly naked singularity (20 SM matter annihiliation?), however I think you can make up a mechanism with that only partially ot for short moments 'opens' the event horizon.\nFor scientists this will be very exciting because it is the first chance to look at a naked singularity. Problem is: Noone can quite predict what will happen, so noone knows the safe distance to observe the event!", "43" ], [ "This is a big one, so I'll split it into parts based on the questions you asked:\n1) Earth has roughly a distance of 1 AU to the sun, Saturn between 9 and 10. Sun's gravity would therefore have a much stronger influence on these rings. Would it already be enough to distort the rings (e.g. even leading to the sun \"stealing\" parts of it) or would the rings still have a ring shape?\nSun would not have too much of an influence because the rings are all individually gravitationally bound to the earth (similar to the moon, and you don't see moon being affected by the sun, gravitationally; the rings will be much closer to the earth and hence even less affected).\nThe moon, on the other hand, would distort a few rings due to orbital resonances (similar to Titan Ringlets: https://en.wikipedia.org/wiki/Rings_of_Saturn#Colombo_Gap_and_Titan_Ringlet and resonant gaps in asteroid belts due to Jovian planets: https://en.wikipedia.org/wiki/Kirkwood_gap), and its effect would be much more pronounced because it is closer to the earth than Titan is to Saturn, though limited to a few resonant regions. There will also be ripples if the plane of the moon is different from the plane of the rings (http://blogs.discovermagazine.com/badastronomy/2009/06/11/saturns-rings-do-the-wave/#.U7VjpvmSw08).\n2) How well would the objects in such rings be visible from earth? The Saturn rings are mostly dust and ice as far as I know, but there are surely some larger objects. Depending on material and size some object would probably be visible to the naked eye, right? Is there (probably yes) a formula to calculate what materials and sizes are required to achieve this?\nMost matter in Saturn's ring is particles up to a few metres in size (http://saturn.jpl.nasa.gov/faq/FAQSaturn/#q6). Resolution of the human eye is about 1' (http://astronomy.stackexchange.com/questions/2398/is-the-moon-only-60-pixels), which means at a distance of around 1 to 1.5 Earth radii (given by Roche limit of the earth; this is where the rings will be), the eye can resolve things above a couple of kilometres in size. However, Saturn also has Shepherd moons, which are a few tens of kilometers in size.", "196" ], [ "Such moons, if present, would be visible to naked eye. Also, the gaps would be visible clearly, since they are often big enough.\n3) Would those rings not be constantly raining particles down on earth? Would there be a much higher risk of dangerous impacts for the earth's population?\nThere would be collisions/interactions in the rings (I'm guessing, correct me if I'm wrong) which would send particles earthwards. However, the particles which will get thrown will be the lighter, smaller ones (conservation of momentum etc.), and usually small meteoroids are fairly harmless. They will also be slower than the usual meteoroids that enter the earth at above 20 km/s, since the orbital motion of the earth doesn't add up in this case. I am a little unsure about the consequences of them being slower, but anyway, smaller meteoroids should technically be fairly harmless. (Also I couldn't find decent references other than: http://science.howstuffworks.com/question486.htm)\n4) Are the colours used in the video precise? Don't they depend on the angle? What influence would our atmosphere have onto them?\nI believe so. This section shows true colour images of the rings from two different angles, and there doesn't seem to be a significant change in the colouration: https://en.wikipedia.org/wiki/Rings_of_Saturn#Subdivisions_and_structures_within_the_rings. The atmosphere will probably affect the rings closer to the horizon, with redder colouration similar to sunrise/sunset and moonrise/moonset.\n5) Would those rings have the same orbital inclination or would theirs differ from earth's to an extent where the difference becomes visible?\nDepends largely on the formation history. This FAQ question here discusses this fairly well: http://saturn.jpl.nasa.gov/faq/FAQSaturn/#q14\n6) What shadow would these rings cause on earth? Would they be dense enough to \"shade out\" complete stretchs of land?\nThere will be shadow similar to that due to clouds, since the rings are not too thick or dense.", "196" ], [ "You could have a look at electromagnetic induction. When the electromagnetic field through a surface surrounded by a conductor changes, this will generate an electric current which in turn generates a magnetic field that resists this change. In the case of a superconductor, the generated field will be precisely strong enough to stop the change completely.\nSince light is electromagnetic radiation, we can imagine a substance which similarly manages to partially or fully cancels out all light that passes through it by generating electromagnetic fields opposite to the waves of the light.\nsevere speculation:\nIt seems like what you'd need to achieve this is a bunch of charged particles that are able to move without resistance. A massless charged particle seems ideal here. Sadly, since it is massless, it would be unable to not move at the speed of light. If they move around in a confined space randomly, they would create an incredibly strong and chaotic electromagnetic field. Though you could just invoke quantum mechanics and claim they move in all directions at the same time (much like particles with mass at rest bounce off the higgs field in all directions at the same time) and therefor create no net electromagnetic field.", "531" ], [ "Another problem becomes simply containing these particles, and this is a big one. You'll have to use electromagnetism to keep these particles together and this will likely be just as difficult as what the particles are doing for you (canceling the light). But could possibly be more straightforward. (Maybe a rather simple, if powerful electromagnetic field would be enough to turn any particle headed out of the confined space around.)\nwhat would this achieve?\nWell, since these particles can only cancel out light within their volume, light would be able to pass through it largely unchanged. However, inside the substance all light would be entirely canceled out. which means that it would be pitch black.\nSo the way to use it is to surround your enemies with it (or just their heads) and though you will still be perfectly able to see them, all they would see is darkness.\nsome possible side effects\nThis would interact with all electromagnetic fields, including that of the earth, so if you move this substance it would generate a field to resist this change. Since this resists all change in electromagnetic fields, it is possible that brains and nerves in general stop working within this substance. I'm not sure how to solve this one without some serious handwaving.", "477" ], [ "There are no undiscovered planets between the sun and Neptune\nObjects closer to Neptune that are large enough to be considered planets (and not dwarf planets) can't remain 'hidden'. If it's there, the light from the sun will bounce off it and we will see it. As it moves in its orbit, we will notice the position in the sky change, so we will know it isn't a star.\nI would like to give a more broad answer to this question though: What is the maximum size of an undiscovered solar system object and how does it change as you get further from the sun?\nThe further out a solar system object is, the harder it is to detect. The rate at which it gets harder is severe; the light we receive from an object scales roughly as $1/r^4 $.\n($1/r^2$ for the light travelling from the Sun to the object, and again, $1/r^2$ for the light travelling from the object to us on earth).\nWe are able to detect some very small earth-crossing asteroids. Some as small as ~50 metres across. At a guess (and this is just based on my intuition, not any calculations), there are probably no undiscovered objects larger than 1 km close to earth.\nAs you travel to the outer solar system (Jupiter to Neptune), the number of bodies increases dramatically. There are currently ~700,000 known solar system bodies and most of them occur in this area. It is believed that all asteroids larger than 10 km have been found.\nIn the area immediately beyond Neptune (30 AU to 100 AU), we have been finding many pluto-like objects in the past two decades, objects with diameters of 500 km or more.", "710" ], [ "For reference, Pluto is about 2200 km across. It is entirely plausible that there are some, if not many, similar objects at this distance range that have not yet been found. Some of these would classify as dwarf planets, in that they are round, orbit the sun, but have not cleared 95% of their orbit of other matter.\nAnd finally - and this is where it gets exciting - where it gets really far out, there may be an undiscovered large planet, out at ~700 AU. Referred to as Planet Nine, this is a hypothetical object that some (noteworthy) astronomers believe exist because of patterns they see in the orbits of other distant dwarf planets. From calculations, they estimate that it would be as heavy as 10 earths and travel between 200 and 1200 AU. However, these distances are so large and the sunlight out there is so dim, that even with the best telescopes and two years of looking, they haven't found it.\nFinally, I'd like to share two graphs. The first one is of distance (of closest approach, or perihelion) vs diameter of various outer solar system bodies. In the bottom right corner there is a noticeable lack of dots, indicating roughly where we don't yet have the capability of seeing objects that small and distant.\nThe second is an expanded but slightly less accurate diagram of the same.", "196" ], [ "While Sir <PERSON>'s post is a very intriguing answer, but I'm afraid it's wrong. The sun's surface is clearly in motion, but that does not necessarily result in the radiation of audible sound, even if the sun and earth where in a fluid medium (such as a air) that would allow sound transfer.\nTo explain why, we can actually apply the same line of analysis to the earths's ocean. The surface moves a lot, so sound should be radiated. However, we hear nothing unless you are really close by and have breaking waves.\nLet's run the math with rough numbers: The ocean has a surface area of about 510 million square kilometers. $150 \\cdot 10^{12} m^2$. Let's say the average wave height is 1m and the average wave frequency is 0.1 Hz (1 wave every 10 s).", "840" ], [ "If the ocean where a sherical source this would create a sound power of $5 \\cdot 10^{24} W$ and the sound pressure at 1000 km away would be 240 dB SPL. That's obviously not the case, otherwise we'd be all dead.\nSo why not? In order for sound to actually radiate, the surface must move uniformly. For every ocean wave that moves air up there is a wave nearby that moves air down and so the contributions simply cancel. Technically speaking, we need to calculate the power by integrating the normal intensity over the entire surface, the intensity has equal amounts of positive and negative components and the sum over those is zero.\nThat's the same reason why you put a loudspeaker in a box: in open air the air motion from the front of the cone and from the rear of the cone will simply cancel out, so you put it in a box to get rid of the sound from the rear.\nSo I think the real answer here is: you would hear absolutely nothing since the sound contributions from different parts of the sun's surface would cancel each other out. Sound radiation over that distance would only occur if the sun's surface moves uniformly, i.e. the whole sun expands or contracts. That does happen to some degree but only at very, very low frequencies which are inaudible and where sound radiation is a lot less efficient.", "309" ], [ "Air trapping polar vortexes on tidally locked planets?\nThere's a tidally locked planet with native life or not, but with an atmosphere that could allow a decent degree of heat transfer between hot and cold side and a rather broad, hospitable region near the terminator.\nEven without rotation, we could expect vortices around the poles - looking at the dayside: Cool air streams, near to the ground, from the night side towards the sunpole, to be heated, rise, and stream back above the incoming cool air. If cool flow is disturbed in any way (say a mountain range roughly along the terminator), this would could introduce a small angular momentum to the incoming cool air which would be greatly accelerated as we get closer to the pole. This alone could in theory lead to a strong polar vortex.\nETA: Coriolis forces are not necessary to create a vortex, as can be observed when emptying a bathtub.", "513" ], [ "A short explanation is found here, indicating that the effect of the coriolis force is rather weak, as shown by an experiment where all other disturbances where eleminated and it took 15 minutes for a vortex to develop due to coriolis effects.\nNow my question is: Would such a circumpolar vortex trap hot (or cold) atmosphere, the way the polar vortices on earth do? Or would it rather be part of a sort of atmospheric conveyor belt, transporting hot and cold air masses around the globe?\nFor the purpose of this questions, I'm only interested in atmospheric vortices, I think asking about marine phenomena would complicate things too much. The worldbuilding aspect is that a tidally locked planet could have those vortices and relatively benign conditions near the terminator - but the vortices break down every few years or decades, sending masses of scorching or freezing air to the terminator. The inhabitants would study chaos theory with religious devotion.\nNote: A previous version of this question considered a rotation around the sunpole-nightpole axis to aid in vortex formation, as a learned discussion in the comment section here and under this (wrong) answer make clear this is impossible.", "513" ] ]

[ 6211, 2925, 4456, 10838, 3011, 6868, 4235, 3256, 4748, 2056, 5370, 10072, 4846, 1074, 3000, 10130, 7831, 1082, 608, 2302, 1006, 8138, 1522, 9866, 366, 2957, 10290, 681, 1088, 9737, 7312, 8136, 11174, 8589, 9918, 3668, 7386, 7155, 11089, 11172, 10868, 4457, 4449, 3063, 9370, 7426, 5140, 6787, 7893, 5449, 8868, 6010, 6237, 9443, 706, 2109, 3511, 445, 11340, 4182, 1924, 7021, 7162, 3318, 6301, 4385, 5023, 6717, 4685, 9163 ]

[ [ "EMS Treating Security Like Shit\nSo I'm on my way out of one of the low income housing units I check and I see EMS coming in.\nI asked them what apartment they're looking for and then tell them where it's at. Then I tell them I'll go with you because I have a master key and I can let them in if the door is locked.\nThis particular apartment building used to be a high-end nursing home. So they have a passenger elevator at one end and an elevator that's big enough to take a hospital gurney at the other.", "859" ], [ "So of course EMS goes to the wrong elevator and I mentioned that the elevator at the other end of the hall will take their Gurney.\nThey look at me like I'm the idiot and leave their gurney in the hallway on the first floor because they can't get it in the elevator (did NOT see that coming).\nSo we get to the third floor and they pile off the elevator and they have no clue where the apartment is at. Which is not surprising because unlike me they're not in that building every night. So I take them to the apartment I step back they knocked on the door and then they opened it.\nAs soon as they opened it I said \"You guys have no further need of me I'm going to leave.\" One of the firefighters looks at me and in the snottiest voice you can imagine says \"Thanks so much for all your help.\"", "107" ], [ "YOU CAN'T SMOKE INSIDE THE BUILDING?!\nThere's this guy that's been a problem for a week now. We've all told management about him but nobody will do anything about it. He's drunk. He's a mess. He's tried to steal from our snack shop. He's honestly a liability with his inability to properly walk down the stairs. I have to watch his door on the cameras to watch him come and go to make sure I don't have to call an ambulance if/when he falls down three flights of concrete stairs.\nTonight he's decided going outside to smoke is too hard. He'll just light up in the stairwell. The first time I go up, I'm not kind. It's a no brainer- YOU CAN'T SMOKE IN HERE.", "670" ], [ "He gets puffy and looks at me with genuine confusion. \"Sir. I mean it. Put it out now. If these sprinklers go off you're liable for the damage for anything in anyone's rooms and to the hotel property. He smokes it all the way down the stairs.\nAn hour later I look up, he's sitting there again smoking. Then, I watch as he throws the lit cigarette down from the first floor. THE LIT CIAGRETTE. Who the fuck does that?\nOf course Management won't answer the phone to make the call to kick him out or not. But I can't keep running up flights of steps to catch homie in the act AGAIN.", "78" ], [ "Needing ID to check-in\nOooh My Turn! This literally happned moments ago.\nTwo dudes come to my desk, one 30ish, one well into his 60s. They are an hour early for check-in, and one of the two rooms they have reserved under a ladies name is ready so I can get them half checked in, if said lady were here with her ID, \"I wouldn't want to give away your reservation to some rando\". People usually laugh and like that, the younger of the two dudes did.\nThe older of the two dudes didn't seem impressed with the comment or ID requirement, so he asked \"Would this make a difference?\" and he literally flashed a police badge at me.", "536" ], [ "(Maybe he considered it a shield? It had that shape.) It didn't have a the ladies last name on it, so NOPE.\n\"Um, no sorry. That's not quite good enough.\"\n\"Oh what, you don't trust cops?\"\n\"No I do, but that's still not ID. Sorry.\"\nThey went to go find the lady with her ID so they could get half their reservation checked in.", "107" ], [ "Bootcamp Cocaine\nI know it's a flashy title but I promise you it's not nearly as exciting as that.\nSo when you get to Parris island or San Diego for summer camp they make you send a detailed list of what is and isn't allowed to be sent to the campers. Protein bars/powder, cough drops, vitamin C pills, etc.\nMy mom being the wonderful woman she is decides to go out and get the biggest damn protein powder she can find at Costco because her scrawny ass boy sure needed it. Well the problem is the post office didn't have a big enough box to fit it. So she did what mothers around the world do and break out the old sandwich baggies......\nYou can see where this is headed. My package comes up in mailcall and I'm asked to open it for the drill instructors. Cue 25 sandwich baggies of white powder.", "119" ], [ "I freeze, the DIs freeze, the Platoon might as well have seen <PERSON>. As the last baggie comes out a note is attached,\n\"Senior Drill instructor **,\nMy son is a scrawny little kid as you probably know. I bought the biggest protein powder i could find for him but couldn't find a box for it. * Told me you normally use sandwich bags to mix the protein powder so i figured I'd save you a step. Please keep taking care of him, he says you're doing a good job of it so far.\"\nI was a Stanchion Recruit, meaning my position was in front of a column and I blended in, didn't fuck up too much nor kicked ass. Before that point (2nd phase) i don't think my senior knew my name. That all changed and I got some extra quarterdecks everytime packages came through since I \"attempted\" to smuggle cocaine onto Parris Island.", "119" ], [ "Taxi Driver with Poor Aim.\nTaxi driver drops off an elderly lady and asks to use the toilet. Normally our policy is only to let our clients use the bathroom however I'm a kind person and know how desperate things can get. He uses the bathroom and leaves. I'm the only person in the office and go to use the bathroom not 5min later and the guy has pissed down the front of the seat, over the floor 1m in a circle in front of the toilet and made no attempt to clean it up.\nHe picks the old lady up 30min later and I take his number down for the complaint to his company.", "828" ], [ "Her dog must have had her phone...\nGot a 911 hang up Yesterday during the pouring rain. Jump out the patrol car, and ran up to the door to get out of the rain and knocked. I could hear people talking and dogs barking. Lady opens the door and immediately I'm hit with the smell of Marijuana. She's high as shit and so is the guy standing behind her holding the barking pitbulls.", "588" ], [ "She looks panicked that I'm there. I ask her if she called 911, she looked so puzzled like wtf is going on. I had to repeat myself. She goes, no, I didn't call, my dogs must have, they had a hold of my phone....I looked at her, I looked at the dogs, I looked at him, he looked at her, and she looked at the dogs. Without saying a word to them I left and cleared. Lmao making me get all wet for this dumb shit.\nAnyway I would post the pic of the drawing my wife drew up after she heard the story, but this group doesn't allow it.", "430" ], [ "The last time I got a call from a family member for help\nSo, my wife and I were out shopping (at Salvation Army actually) when our 2nd oldest daughter messaged her (not sure why her and not me) about her pc issue. My wife let me know and I called her. She was in a PANIC!\nI'm like - what's going on? She says that her laptop booted SUPER slow - like half an hour and that everything was running \"stupid\" slow.\nI told her to put down the panic and unplug the laptop. She went ballistic. What do you mean? What does THAT have to do with anything?\nHoney, for me, just please unplug the goddam laptop.", "648" ], [ "A little bit more grumbling and she agree to pull the damn plug.\nSo what happened I asked. It's, it's working normal again. Yes, I know it is. Go buy yourself a new power supply. :-)", "107" ], [ "I bring my Doctor with me to the pharmacy.\nThis summer I flew out of state to visit and vacay with an old friend who happens to be a doctor.\nWhen I got to his house and unpacked I realized I had forgotten to bring a prescription medicine that I need to take everyday. He said it was no problem and called a prescription in to the pharmacy at Wa**art. Then we went out hiking and playing and getting dirty, dressed kinda outdoor scroungy.\nWhen we were done playing we went to the pharmacy to pick up my pills. I went to the pharmacy counter while my Dr.", "940" ], [ "buddy stood back 6' behind me. It probably looked like he was the next customer in line behind me. Honestly, we both looked kinda grungy from a day of fun.\nThe young lady behind the counter tried to look up my presc. and dismissively said she couldn't find any record of it in their system. period.\nFrustrated, I sarcastically said, \"well if my doctor were standing here could he write this prescription for me?\"\nShe said \"Yes.\"\nSo I smiled, turned around and motioned to my doctor buddy to come to the counter as I said \"well he's right here.\" He stepped up, identified himself, asked for a prescription pad and wrote out my prescription.\nNot very malicious but we guessed that that was a first for her.", "931" ] ]

[ 11181, 4045, 3344, 1401, 9822, 8235, 23, 7350, 10471, 1691, 2184, 2795, 2888, 10883, 10384, 7067, 7713, 8472, 9440, 8191, 7688, 2686, 4597, 6160, 1638, 4396, 9859, 649, 3847, 1611, 8355, 814, 6939, 1037, 10903, 5053, 4637, 5205, 774, 8606, 5353, 2634, 4518, 3760, 717, 3272, 2860, 6883, 2639, 3470, 6058, 7047, 9219, 3749, 897, 5279, 238, 1984, 8962, 128, 4815, 4260, 8526, 4455, 8034, 2346, 7724, 1813, 7345, 2772 ]

[ [ "Sonic the Hedgehog\nFor the last 3ish weeks I changed all my dating app bios to search not for love, not for a hookup but to find someone to go to this movie with. The results are that I've seen this movie 4 times on 4 separate dates. It started as a joke after all my friends turned me down because this movie happened to open on Valentines' Day (or because everything in the lead up to release suggested that this was not worth the time or money... who knows?).", "233" ], [ "I wish this was the genesis (get it?) for some grand love story but it's not. Trust me I wish it was because few things would give me as much joy as telling the world that I met the love of my life in a movie where <PERSON> dances multiple times and makes terrible puns\nBeyond the desire to find someone that you can have these long stimulating conversations on art and life like a real-life version of Before Sunrise with and arguably equally important is the ability to laugh and appreciate the imperfection of it all. Sonic the Movie is as flawed as they come yet perhaps disappointingly not so flawed that it becomes a great meme movie in the vein of The Room or The Snowman. What it is, however, is a dumb fun time at the movies and a surprisingly good date movie.", "292" ], [ "Thanksgiving\nI wanted to like this more than I did. I love slashers but there's a few aspects here that I feel like distract a tad and work against each other. One being I'm waiting around for the movie to recreate scenes from a trailer I saw 16 years ago. That creates a sort of auto pilot.", "596" ], [ "Another thing is the huge plot points hinging on social media and live streaming that feels so against the grain of that Grindhouse trailer. Plus adding in a Black Friday stampede feels more 16 years ago then now. So I kinda found this to be all over the place. That said, I'd absolutely watch a sequel because we need more slashers in this world.", "269" ], [ "Sliding Doors\nIt’s the year 2002 and <PERSON> is riding the tail end of her peak. Newly released DVD Shallow Hal is out of stock at the local blockbuster so a 10 year old me is tasked with choosing between <PERSON>’s Shakespeare in Love and this. I chose <PERSON> in love then so now because there’s no alternate timeline I finally decided to see if I missed anything. Turns out I didn’t.", "378" ], [ "Watch Right Now Wrong Then for a much better example of this concept done well\nStray Observations\n- The ending(s) are awful. Like soap opera awful\n- the soundtrack slaps including <PERSON>’s Thank You over the credits\n- the main love interest’s one line is to make the same Monty Python reference and somehow it works every time. (?!?!)\n- <PERSON>’s hair in this is fantastic and so 90s. Her British accent though? Not so fantastic.", "952" ], [ "Scream\nI’m slacking off in my posting reviews but in anticipation of Scream (2022) I’m revisiting a series that is like an old friend to me. This film was something that I was dead centered in the middle of the demographic. I was a <PERSON> horror dork. I was dying to see it and when it didn’t get one to my town’s 5 theaters til January I went and saw it with my best friend and little brother and a couple more times by myself.", "444" ], [ "The movie was mind blowing; scary, an intriguing whodunnit, funny and meta af. It was like nothing I’ve ever seen. Sure we might get a small mention of “I’ve seen enough horror movies to know anybody wearing a mask is it up to any good line being used in Friday the 13th VI Jason Lives for example but never had I heard characters in a horror movie discus the rules of horror movies lol\nIt’s such a time capsule and really brings me back to being a teenager who was jealous of the previous generation (primarily my aunt, uncle’s and grandmother) who enjoyed Halloween in the theater but thinking about how the slasher revival was OUR TIME! I absolutely love the nod of playing Halloween on the tv 📺 in the party finale it works so perfect and the “ Behind you <PERSON> gets a laugh out of me 25 years later”. Also huge nods to having a cover of Don’t Fear The Reaper and a character with the last name of <PERSON> lol Though don’t think too hard how scream 2 could be playing on tv in h20 when it’s Halloween (1978) was featured on tv in Scream (1996) ‘a climax... 🤯🧠🤷🏽\nRevisit was fun on to part 2\nScream Uuuuuuhhhh I see it coming up next", "995" ], [ "Interview with the Vampire\nMy movie watching lately has pretty much been the occasional theater appearance and following up with the books I have been reading. I finished Interview With The Vampire last month and now I finally got to a rewatch. I think the film does a good job at capturing the main structure of the novel.", "79" ], [ "It is much breezier and things are changed and left behind but nonetheless, it’s a solid film. The casting was spot on if you ask me. I had a great time rewatching this after not see in for roughly 20 years.", "583" ], [ "Guardians of the Galaxy\nMaybe because it was \"phase two\" and not focusing on a big recognizable superhero but this movie feels like a movie despite having <PERSON> and an infinity stone in it. It could possibly be a fully contained movie or franchise on its own. That's all I want, make me feel like I saw a thing and not thing 10 out of 31 things and counting.\nThe comedy and lil serious-y moments work too. <PERSON> with this series, that better Suicide Squad movie, and the Peacekeeper series shows that yeah, he's probably at the top of this dying heap of capes.\nThat said I'm dreading Vol 3! But hey 🤞🏻", "995" ], [ "The Sixth Sense\nTo paraphrase another great <PERSON> movie, a movie never changes. It just seems different because you’re different. The Sixth Sense lives in a weird fixed point of pop culture history. It was everywhere, obviously a major box office success but endlessly parodied and dissected and referenced for years and years and years casting a major pall on <PERSON> as the twist ending guy.", "952" ], [ "It's not fair to devolve this movie down to its very well executed twist. It's just a well executed movie on every level and the twist is what people came away talking about (except me, I had the twist ruined for me in 1999 and the part that upset me most was a mother willingly poisoning her child, a banal and terrible evil that my 14 year old mind had never even considered a possibility before this movie).\nToday I came away from The Sixth Sense really impressed by all the craft on display, especially <PERSON>. You can count the amount of truly great child actors on at most two hands and he is on the list. But <PERSON> himself really just stepped up to the plate in his late twenties and smacked out a home run. You can debate whether or not he ever did it again (he didn't) but find one other writer director who came out swinging so hard so shortly after becoming of rental car age.", "292" ], [ "Talk to Me\nFeels like the good concept-heavy horror films of the 2010s like It Follows but bogged down by the more modern Hereditary / Us family drama that I really don't find much interest in. If this didn't screech to a halt halfway through to focus on a non-interesting mother-daughter plotline then it'd be really really good for me I think.\nI still don't care much for the ooey gooey designs of the spirits, but the vibes are fun until that point and the concept is real neat throughout. Some great haunting moments here and there, but I'm getting very tired of the <PERSON>-bash-his-head-into-school-desk shtick.\nHaving spoken negatively about the main plotline however, I do think a film has never won me over by such a far margin as this one by its ending.", "823" ], [ "Brings it all back in a really rewarding way that condemns the character appropriately. Made me smile all silly like. Sequel already in the works tho 🪨", "583" ] ]

[ 8448, 4032, 7455, 629, 10877, 3911, 2307, 5609, 10850, 7990, 5446, 6799, 8935, 7503, 9571, 10467, 10165, 6665, 9352, 5750, 11012, 2347, 4299, 2049, 7898, 4498, 3730, 9344, 4114, 9054, 465, 9180, 727, 9019, 4335, 8258, 7218, 10314, 7341, 4304, 8942, 2625, 8540, 8648, 3841, 8071, 2381, 10879, 3053, 7816, 8665, 7973, 10719, 1566, 8792, 954, 1651, 5825, 3178, 3735, 5463, 5060, 4696, 9602, 5982, 6657, 7525, 2005, 3364, 3570 ]

[ [ "You seem to have asked multiple questions, and the answers to them are not all the same. So let's start with the physically observable ones, that we could in principle test to see what happens, before getting into any philosphical arguments about the \"centrifugal force\" and whether it really exists or not.\nWill an object which you place inside the 'pipe' of the [vacuum-filled] torus […] be attracted to the edge of the torus?\nNo, it would not. With no contact between the object and the torus, they do not interact in any way,* and in particular, the torus cannot exert any force on the object. Thus, the object will behave in the same way (i.e. floating in place) regardless of whether the torus is actually there or not (and also whether, if present, it is spinning or not).\n*) I'm neglecting any gravitational and long-range electromagnetic interactions between the object and the torus here, as well as even more subtle effects like relativistic frame dragging. In principle, those could all transmit forces between the torus and the object, but in practice, assuming that neither the object nor the torus carry any significant electric charges or magnetization, those effects should be negligible.\nOr would it only experience the force if it was originally touching one of the walls?\nIf the object was touching the walls of the torus, then contact interactions (i.e. friction, or, if you want to get ultra-reductionist, short range electromagnetic interactions) can transmit a force from the torus to the object, giving it a net relative velocity tangential to the wall.\nAs the outer wall of the torus is curved, whereas the inertial trajectory of the object is not, this will push the object against the wall — which, being solid, will push back, and will also exert further frictional force on the object as long as its velocity differs from that of the rotating wall.\nEventually the two will reach an equilibrium where the tangential velocity of the object equals the rotational velocity of the wall, so that there is no lateral movement between them, and so no friction forces.", "343" ], [ "The only force exerted by the wall on the object at that point is the normal force that keeps the object from passing through the wall, and instead pushes the object towards the axis of the torus's rotation with just enough force to keep its trajectory circular. From the viewpoint of someone rotating along with the torus, the object has simply come to rest against the outer wall.\n(While writing this, it occurred to me that it should be totally possible to do this in Kerbal Space Program, and indeed, it turns out that someone already (kind of) has. Alas, the video doesn't really demonstrate it as clearly as it could, but if you look around 1:30, you can see the rover floating inside the spinning ring until the player fires some thrusters to bring it into better contact with the ring. Also, around 5:25 the rover briefly takes off by driving against the rotation of the ring (and hitting a slight bump).)\nAnd would the results be different if the torus was filled with a gas (air)?\nYes, because, even if the air wasn't initially rotating, aerodynamic drag forces along the walls of the torus would eventually cause the air to start rotating together with the torus. Those same drag forces would also then cause the object to move along with the air, which would eventually bring it in contact with the outer wall of the torus.\n(For more details, you may also want to take a look at this thread on Science Fiction Stack Exchange, which concerns the physics of a helicopter flying inside a rotating air-filled space station.)\nAnd if the inside of the torus was divided into sections (like the ship)?\nIf interior of the torus was in vacuum, but had radial walls dividing it into sections, then there would initially be no force exerted on the floating object. However, since the object is stationary but the section walls are rotating with the torus, one of them would eventually hit the object, imparting some non-zero tangential velocity to it. Again, this velocity would eventually bring it into contact with the outer wall.\nOK, with the practical questions out of the way, let's get to the philosophical part:\nWill an object which you place inside the 'pipe' of the torus experience the centrifugal force due to rotation?\nWell, first of all, let's keep in mind that the centrifugal force is a \"fictitious force\" that only appears in rotating coordinate systems.\nWhat does that mean? It means that, if we're looking at (for example) a rotating torus from the outside, but not rotating ourselves, then there is no such thing as a centrifugal force: there's only inertia (i.e.", "621" ], [ "The centrifugal force is a \"fictitious force\" that appears when working in a rotating coordinate system. Basically (together with the Coriolis force) it's the imaginary force that would, if real, make objects move with respect to a fixed, non-rotating coordinate system in the same way that they actually move (due to inertia) with respect to the rotating coordinates that we're using.\nIf all that sounds really confusing, please see the second half of this earlier answer I wrote, where I try to explain this in more detail (and with pictures!).\nAnyway, the point of these fictitious forces is that they let us apply the same laws and formulas of Newtonian physics in a rotating frame of reference as we would in a non-rotating one, and still get physically correct results, as long as we remember to also include the effect of those imaginary forces on all objects.\nFor example, in a normal non-rotating coordinate system, a stationary object will remain stationary if (and only if) all the forces acting upon it cancel out, so that the net force acting on the object is zero. In a rotating coordinate system, an object which is stationary with respect to the coordinates (i.e. rotating along with them around the same axis at the same speed) will remain so if (and only if) all the real and imaginary forces acting on it cancel out, leaving an (apparent) net force of zero.\nHere's a simple example, taken from the answer I linked above. Imagine two spheres floating in space near each other.", "562" ], [ "If you do nothing, they'll just keep floating there. If you push each of them in different directions, then they'll each float in the direction you pushed them, away from each other. But if the spheres have been tied together with a string, then the tension of the string will exert a centripetal force that will curve their trajectories into circles:\nNow, if we look at the same system of two spheres and a string in a coordinate system which is rotating along with them, then the spheres will look as it they were motionless. But clearly something is still pulling the string taut (and, if it's elastic, stretching it), counteracting the tension force that is pulling the spheres together. We call this apparent force (which is really just inertia, hidden by the fact that our coordinate system is rotating) the \"centrifugal force\":\nIn this example, since the spheres are motionless with respect to the rotating coordinate system, and since the centripetal and centrifugal forces balance out, they will remain motionless with respect to the rotating coordinates — i.e. they will continue to rotate around the same axis at the same speed.", "461" ], [ "Does gravity cause the Earth's equatorial bulge?\nThe way I understand centrifugal force, I don't see how Earth's daily rotation alone would cause equatorial bulges to form. The usual explanation is that the centrifugal force increases with distance from the rotation axis, and since this distance varies from the poles to the equator, the equator experiences a greater centrifugal force and bulges. My understanding of centrifugal force is a little different. Consider two observers, $1$ who is on a space shuttle in orbit around the Earth, and $2$ who is stationary relative to the distant stars. From $1$'s perspective, it is not the shuttle that is orbiting the Earth, but instead the Earth that is orbiting the shuttle. $2$ sees gravity providing the centripetal acceleration required for the shuttle's orbit in the $1$-to-Earth direction, while $1$ sees a pseudo centrifugal force providing the centripetal acceleration required for the Earth's orbit in the Earth-to-$1$ direction.", "319" ], [ "The two always point in opposite directions (they are 180° out of phase), just like any other pseudo force. If $1$'s orbital radius was bigger (but the angular rate was the same), then $1$ would indeed see a greater centrifugal force, but only to the extent that the Earth's orbit \"balances\" to make up for its increased orbital circumference. The point is that $1$ would not expect the Earth to stretch in any way due to a greater centrifugal force, only for it as a whole to accelerate faster to make up for the fact that they themselves are accelerating faster because their orbital radius is bigger. If we pretend $1$ was a small volume of mass at the equator, then the same argument applies and $1$ should not expect the rest of the Earth to stretch, only to accelerate fast enough to balance its orbit around $1$.\nIf the argument is to make an analogy to the radially-outward force you feel when you are on a spinning amusement park ride (such as Night Mares at Canada's Wonderland), then my understanding is that the force you feel is the force between your feet, which are connected to the ride by friction, and the rest of your body, which is only dragged along by your feet.\nThe only way I can see bulges forming under rotation is by the fact that gravity points towards the Earth's centre, not its axis of rotation. Thus, gravity is not purely perpendicular to the axis, but has a parallel-to-axis component which makes up 0% of the total at the equator and 100% of the total at the poles. Because of the fact that Earth is spinning, it does not compress under its own gravity, but this is only true at the equator; there is no centripetal force at the poles, so the poles compress under gravity, and the excess mass finds its way to the equator and bulges.\nIs this the correct line of reasoning, that gravity along with rotation causes the equatorial bulge?\n(I'm sorry if this makes no sense at all!)", "393" ], [ "Since we know the position of the source of the photon, we can determine its trajectory from the source to the detector, once we know its final position on the detector.\nPhotons don't have trajectories. It's perfectly possible to consider a situation where you know the starting point of the photon to a high accuracy (say, you know it was produced at a molecule which is tightly bound at a specific location) and that you know the position at which it was detected (you know which pixel clicked), but that knowledge does not tell you anything about what happened between those two times. If you are not actively performing a projective measurement on position (resp.", "400" ], [ "momentum) at a given time $t$, then QM is explicitly restrained from saying anything about that position (resp. momentum) at that time.\nI see nothing that would prevent, as a practical matter, such a detector from also giving us the energy of the photon to arbitrary precision, subject only to practical, technological constraints.\nSince the speed of light is always $c$, and the formula for the momentum of a photon is simply $h/\\lambda$, it follows that we can calculate the position, and momentum of the photon, without any apparent constraints that relate these two values.\nIt's perfectly reasonable to add a spectrometer behind your detector pixel so that you also do a projective measurement on frequency, and this does give you a definite value for the photon momentum.\nHowever, that procedure doesn't tell you anything about the direction in which that photon is headed, so you don't have any real knowledge of the photon momentum, which is a vector quantity.\nMoreover, the fact that you're post-selecting on the photon frequency means that the initial pretense that the photon frequency was undetermined can be stripped away in this context, and your configuration is equivalent to one in which you knew perfectly well (say, because of the way you've tuned your molecule's emission lines) what the photon frequency was. In that picture, you have a molecule emitting a narrow-band single-photon wavepacket, which immediately proceeds to fill up all of the available space in whatever Helmholtz mode is driven by the transition, evolving into a complicated spatial wavefunction with a large spatial and momentum support, which covers a large fraction of your detector, after which one of the detector pixels clicks.\nAnd once you frame things like that, it should be clearer that the information offered by that detector click is rather limited, since the next time you re-run the experiment you'll get a click from a different pixel.", "795" ], [ "First you must understand how a (primary) rainbow is formed. Here is a summary with some details that are not in the linked article:\nWhenever a beam of light encounters an air-water boundary, it is either reflected or refracted. To form a primary rainbow, we must first have enough small water droplets in the air, as these are close to spherical. Parallel light beams that reach such a water droplet must be refracted once as they enter, reflected off the inner surface of the droplet once, and refracted once more as they exit:\n(image from the linked article)\nThere are 3 important points to note here:\n1. Water droplets in the air are never perfectly spherical. That is one source of fuzziness.\n2. Parallel beams entering the same water droplet can exit at different angles! This is the major reason why rainbows can never give sharp spectra even if you have perfectly spherical water droplets (say in outer space). Why then do we still see the rainbow? There are three reasons, which together result in the rainbow being seen roughly at 42°:\n3. Different incident light beams will have different amount reflected/refracted.different incident light beams will have different amount reflected/refracted.", "970" ], [ "In particular, the bottommost incident beam (in the diagram) will mostly pass through without being reflected at the back of the droplet, and the topmost incident beam will mostly be reflected rather than enter the droplet.\n4. The light beams emerging from the droplet after the above process are 'denser' along the so-called caustic ray, because the emergent angle does not vary monotonically with the distance of the incident beam from the central axis, and it reaches a maximum for the caustic ray, around which the emergent angle varies less.\n5. The incident light beams further from the central axis undergo greater refraction, hence resulting in greater separation of different wavelengths. In contrast, the rainbow rays from incident beams close to the central axis largely overlap one another and wash out. (See this webpage for an image illustrating this.)\n6. Light beams may encounter more than one droplet! This is another major reason why we cannot expect a sharp spectrum from a (natural) rainbow.\n7. Even if we assume that the water droplet is a point, the light beams from the sun will not be perfectly parallel. In fact, the sun subtends an angle of about 0.5° to an observer on Earth, so this leads to roughly that same amount of spreading of the rainbow as compared to one generated by a point light source. Still, this is a much less significant effect than point 2.\n(<PERSON>'s answer is incorrect but inexplicably has lots of upvotes.)", "70" ], [ "This problem doesn't have spherical symmetry, so there's no way to use <PERSON>'s Law directly. (If I understand what you wrote correctly, you appear to be implicitly assuming that 0 charge enclosed in a region implies that $E = 0$ on its boundary, but this is only the case if there is sufficient symmetry; in general, all <PERSON>'s law says is that the flux through the boundary of some region is equal to the charge enclosed.)\nLike you say though, you can treat the problem as the superposition of a sphere of uniform density $\\rho$ and a smaller sphere of uniform density $-\\rho$, then use <PERSON>'s Law on each of these systems separately, since they do have spherical symmetry (albeit with different origins).\nHope this helps. Happy to elaborate further if necessary.\nClarifications:\nSuperposition is just the idea that if you have two charge distributions $\\rho_1$ and $\\rho_2$ that alone create electric fields $E_1$ and $E_2$, then the charge distribution $\\rho_1 + \\rho_2$ will have electric field $E_1 + E_2$.", "903" ], [ "This may seem like a trivial statement, but as you can see in the above problem it turns out to be quite powerful (and yes, here $\\rho_1$ and $\\rho_2$ correspond to two spheres which overlap in the region with zero charge, since $\\rho_1 + \\rho_2 = \\rho -\\rho = 0$ here).\nSpherical symmetry occurs when all directions from the origin are indistinguishable in a system. So a uniformly charged sphere has spherical symmetry, but in the above problem there isn't spherical symmetry since the $y$ direction is distinguishable from the other directions (since there is a hole in the charge distribution.\nIf you have spherical symmetry, then you can assume that the electric field at radius $r$ from the origin points radially and only depends on $r$ (i.e., not on $\\phi$ or $\\theta$). This allows you to convert the surface integral in <PERSON>'s Law to the form $$\\int_S \\mathbf{E} \\cdot \\mathbf{da} = 4\\pi r^2|E|,$$ which then allows you to calculate the electric field directly.\nBut it's really important to realize that this only applies when there is sufficient symmetry (which means spherical symmetry here, but could also mean cylindrical or planar symmetry in other problems). Otherwise, the surface integral cannot be simplified further, so you have to be more clever, which in the case of the above problem means using superposition to reduce the problem to two which do have sufficient symmetry to simplify the surface integral.", "903" ], [ "I agree with you: if that's the whole answer the book gave, then it's a very poor answer.\nSure, you can easily deduce from a symmetry argument that the system of two (otherwise) identical charged spheres must have an equilibrium where the charges on the spheres are identical. However, on its own, this argument does nothing to establish:\n1. that this equilibrium is stable, and\n2.", "359" ], [ "even if it is stable, that it will actually be reached from the given initial conditions.\nFor an example of where condition #2 fails, note that the same symmetry argument could equally well be used to argue that the symmetric situation, with both spheres charged to $Q/2$, is also an equilibrium before the spheres are brought into contact. This is perfectly correct, as far as it goes — but without a conductive path between the spheres, the system can't actually reach that equilibrium, unless it starts there.\nFor a striking example of condition #1 failing in electrostatics, see the Kelvin water dropper — a very simple symmetrical device that spontaneously (under the action of gravity, which also obeys the symmetry) breaks the symmetry and generates an increasingly asymmetrical static charge.\nThat said, symmetry arguments are hardly useless. In particular, if it can be shown that the symmetric equilibrium is the only possible one, that the dynamics of the system do not diverge beyond the range where our simplified model of it is valid (as happens in the Kelvin water dropper), and that the system cannot approach a cyclic or a chaotic attractor, then it can indeed be shown that the symmetric equilibrium must be stable and all dynamics must tend to it.\nNow, these extra conditions may seem pretty hard to prove in general, but often they can be established a priori, just by noting that the system under consideration belongs to a class that doesn't exhibit such behavior. Also, even if we cannot (yet) rigorously show that the symmetric equilibrium indeed is the only possible attractor, just knowing that it exists can often guide our intuition, and can allow us to derive useful conditional results by assuming that, in absence of any external forces or constraints preventing it from doing so, the system will tend to this equilibrium.", "298" ], [ "The electric field assigns a single vector quantity to each point in space (specifically, the direction in which a positive test charge would accelerate if it popped into existence at that point, assuming it didn't perturb the setup creating the field in the first place). I believe that the difficulty of this question arises from an ambiguity in the problem statement: to which point(s) do the two vectors you have drawn assign electric fields?\nThey cannot both correspond to the single point P_lr at which the drawings of the left and right arrows intersect (the head of one touching the tail of the other) because this would imply that a test charge dropped at P_lr would accelerate simultaneously in two different directions! You could adopt the convention of summing the accelerations a la Newton II, since two forces F1,F2 that would have caused accelerations A1,A2 if applied separately actually cause acceleration A1+A2 if applied simultaneously. But this would force you to admit, by the definition of the electric field, that E(P_lr)=E_l+E_r which points along the wire and does not violate the rule that the drawing was intended to be a counterexample of.\nWe could adopt a different convention for deciding which points the arrows assign electric fields to (perhaps taking the point to be the tail or the tip of each arrow). But this arrangement does not imply anything about current building up or not building up in either place.\nLet me propose a slightly more formal version of your question: what prohibits the inside of a wire from sustaining a solenoidal (circulatory) vector field? Solenoidal vector fields don't converge or diverge (lead to charge buildup) anywhere, but they are not necessarily equal to zero. An example would be the velocity field of a 2D whirlpool.\nThe answer: nothing! You can generate one of these fields by accelerating a magnet through a pipe. The electrons are dragged around the pipe in circles, which produces a magnetic field opposing the field of the falling magnet.", "780" ], [ "If you use an everyday conductive material like copper, a constant acceleration force like gravity will inevitably \"win\", since resistance takes away some of the electrons' ability to build a perfectly opposing magnetic field. As they rotate around the pipe in circles, their potential decreases to 0, which means that there must have been a circulatory electric field in the wire.\nHowever, if you use a superconducting material, circulatory currents are able to perfectly oppose impinging magnetic fields, leading to the <PERSON> effect (superconducting levitation). If you made a superconducting wire and placed a magnet nearby, the wire would have all sorts of circulatory currents on the inside that did not point along the length of the wire, but these wouldn't necessarily be due to electric fields since superconductors don't require electric fields to sustain currents.\nAnother possible way of obtaining circulatory fields in the wire would be a high-frequency alternating current (google \"skin effect\" if you're interested), although the elementary description of the physics is a bit more complicated in that case.\nI would hazard a guess that the context of this question implicitly forbade arrangements consisting of moving magnets and alternating currents. Mathematically, the condition of \"no changing magnetic fields\" implies that there are no circulatory electric fields. By the <PERSON> decomposition (vector fields can be written as a sum of an irrotational and a solenoidal field), the earlier argument that the current (and therefore E-field, in a non-superconductor) must be divergence-free suffices to prove that the field is constant, and the fact that it must have no component normal to the wire surface then suffices to prove that the field must be constant AND point along the direction of the wire.\nI don't know what mathematical background you have, so if the talk about Helmholtz decompositions didn't ring a bell then you'll have to wait for vector calculus.\nSummary: the confusion was due either to a misunderstanding of the definition of \"vector field\" or due to implicit assumptions (no changing magnetic fields, no changing electric fields) in the problem statement. Hope this helped :)", "395" ] ]

[ 809, 7249, 8199, 1088, 7819, 9490, 1522, 3063, 10000, 9593, 2441, 4522, 6772, 1528, 6936, 9210, 2285, 4983, 3134, 1063, 1140, 3385, 3060, 264, 6868, 3256, 1278, 10474, 10580, 5839, 5686, 366, 7652, 1954, 3762, 6237, 4259, 4472, 1006, 2922, 4457, 8138, 3924, 3774, 7320, 11337, 6357, 3830, 3327, 7062, 9131, 6830, 1226, 4846, 3309, 10952, 5604, 1795, 10004, 6819, 11069, 3328, 8217, 10264, 1082, 9738, 4489, 641, 11151, 9079 ]

[ [ "Savory Momos, Sweet Sel Roti and 5 Other Delicious Nepali Delicacies · Global Voices\nNepal, a land of diverse culture and tradition, has its own unique dishes that leave the taste buds craving for more. The delicacies presented here have been selected from hundreds of mouth-watering recipes originating from the high mountains to the Nepalese plains.\n1. Sel roti\nThe famous Nepali crispy doughnut (sel roti), a must during the Tihar or Deepawali festival, is prepared from rice flour.\nSee NepaliMom’s instructions to cook the doughnuts:\n2. Gundruk\nGundruk, a popular dish among Nepalis, is prepared by fermenting and drying leafy vegetables, namely mustard and radish leaves. The blog Nepali Local Food explains how to cook gundruk ko jhol (soup).\nGundruk ko jhol (soup)\nServes 6 to 8\nGundruk/Sinki 50 g\nOnion 1 chopped\nTomato 1 chopped\nDry red chili 2 pods\nTurmeric powder 1/2 Tablespoon\nSalt 1 Teaspoon\nMethod: Soak Gundruk/Sinki in water for 10 min. Heat oil and fry chopped onions, tomatoes, chilies. Drain up soaked Gundruk/Sinki and fry, add turmeric powder and salt, and put 2 cups of water. Boil for 10 min, and serve hot with cooked rice.\n3. Momo\nA typical serving of momo with sesame yellow sauce and red ginger chilli sauce in Nepal. Image from Wikimedia Commons by <PERSON>. CC BY-SA\nMomo, a type of Tibetan dumpling, is so popular among Nepalis that it could be considered the country's top dish. The ubiquitous restaurants selling the dumplings generally stuff it with minced buffalo meat, chicken, mutton or vegetables.\nCheck out the step-by-step momo cooking guide in the Taste of Nepal blog. Or watch a YouTube video posted by <PERSON> showing how to cook them:\n4.", "863" ], [ "Chhoila\nChhoila, a favourite dish among the Newars of Kathmandu Valley, has become popular throughout the country. Generally made from buffalo meat, the burnt version called “haku chhoila” (black chhoila) is very tasty. Check the <PERSON> blog for details of cooking chicken chhoila.\nWatch Babus Cooking demonstrating chhoila preparation:\n5. Chatamari\nChatamari, also called Nepali pizza, is a kind of rice crepe made famous by the Newars of Kathmandu Valley. The blog We All Nepali offers details on how to prepare it.\nSee how chatamari is made in this YouTube video by <PERSON>:\n6. Bagiya\nBagiya is a healthy and delicious dish made from rice flour savoured especially during the Deepawali festival in eastern Terai of Nepal. It is a special to the indigenous Tharus. While Tharus in eastern Nepal prefer flat bagiya with lentils, the Tharus in western Nepal prepare bagiya in a tubular shape without lentils, explains the blog Voice of Tharus.\nLearn how to make it via Voice of Tharus:\nSoak the rice is soaked in water and mill it in a dheki, the traditional rice milling machine. The taste of the flour ground in a dheki is many times better than the one ground in a rice mill.\nSift the flour and fry it in an iron cauldron (Don't add oil and keep in mind not to burn the flour).\nMix warm water to the flour and knead enough to prepare a tender dough.\nSteam lentils and add spices, ginger, mustard oil and salt to it.\nMake round dumplings out of the dough. Bore a hole, put the mixture of lentils and spice and flatten it with the palms at the middle and leave both the ends protruding out.\nSteam the dumplings over a clay pot of boiling water.\nServe the steamed bagiya with chutney or vegetable curry.\n7. Sidhara\nSidhara cakes. Image via author courtesy Voice of The Tharus blog\nSidhara is prepared from taro stem, turmeric, and dried fish. The aroma is pungent and the taste bitter, but still it is one of the delicacies eaten by the Terai dwellers especially indigenous peoples like the Tharus, Danuwars, Musahars and others.\nThe blog Voice of Tharus details the cooking of <PERSON>:\nGather the Dedhna and Ponthi varieties of fish. Both the varieties are found in abundance in the paddy fields and public water sources.\nDry the fishes on sun.", "863" ], [ "The favorite dishes of Nepali chef <PERSON> · Global Voices\n<PERSON>. Image used with permission.\nAfter finishing in second place in the 2020 edition of BBC's “MasterChef: The Professionals,” London-based Nepali chef <PERSON> became a household name both in UK and Nepal. During the run-up to the finals, the 35-year-old chef presented before the judges a variety of dishes that are little-known outside Nepal.\nBorn and raised in Karjanha, Siraha District of Nepal’s southern plains, <PERSON> toiled up a hill to reach where he is today. After failing his school-leaving exams, he moved to India to work as a dishwasher at a five-star hotel. There, he rose through ranks to become a cook.\nIn an interview with Nepali Times, <PERSON> says he took a risk when he moved to London in 2010, but it paid off as he began working with renowned chefs. At the time he entered the MasterChef competition, he had been experimenting with Nepali food for two years in restaurants in the British capital. The judges appreciated the food items he prepared and presented, such as kodo (millet) pudding, amot (mango leather), crispy stuffed okra, yomari, chicken chilli, and crab curry.\nKodo ko khhir, Amot, timur biscuits besan ani gheu bat banako, poleko aamp, kagati ra pani ko baraf.\nKodo Millet pudding, Mango leather,\nswichwen pepper biscuits made with clarified butter and gram flour, chargrilled mango, lime and mint sorbet.", "765" ], [ "I really wanted to show this. pic.twitter.com/ekqYQP3Vw5\n— <PERSON> (@chefsantoshshah) December 16, 2020\nNepalese Expat <PERSON> tweeted:\nसिरहा करजनहा गाम के @chefsantoshshah\nतराई के फोफी से ल्याके योमरी तक नेपाली परिकारके विश्व सामु प्रस्तुत कैरके आई नेपालके भाइ जी\nफाईनल मे पुग्लै बहौत बहौत शुभकामना भाइ जी।अहिने नेपालके नाम चम्कावु?\nHuge congratulations and best wishes! ?? pic.twitter.com/vSwlQiS9JQ\n— Arun chaudhary (@aryankec) December 13, 2020\nBy presenting Nepali cuisine to the world, from the tubular papadum (fofi) from the terai to yomari, Chef <PERSON> from Karjanha Village in Siraha has reached the finals. Best wishes, brother. Shine the name of Nepal like this only.\nGlobal Voices chatted with Chef <PERSON> on WhatsApp to know about Nepali food he loves and would like to promote.\n“I love biriya (a delicacy from the Terai region),” he said. “Biriya cooked with newly harvested potatoes are my best.” Biriya is made of grass peas, mustard greens or broadleaf mustard leaves wrapped in black gram paste and dried on the sun. They are then stored to be cooked in the rainy season when green vegetables are scarce.\nView this post on Instagram\nA post shared by <PERSON> (@sankuchy)\nAnother dish Santosh would like to promote is Airkanchan, which is also popular in Bihar, Jharkhand and other Indian states. Taro leaves, pasted together with rice flour or gram flour paste and cut into small cutlets, are fried in mustard oil and then dipped in a gravy of curd and spices – it’s hot, salty and sour!", "765" ], [ "A favourite Nepali hard cheese finds favour with canines · Global Voices\nChhurpis hung up for sale in a shop in the Ilam District of eastern Nepal. Photo by <PERSON>. Used with permission.\nAs you pass by the misty Kanyam tea gardens in the Ilam District of eastern Nepal, you will come across bunches of hard cheese hanging in most of the shops.\nThe hard cheese, known locally as chhurpi, is made from milk collected from naks (female yaks), cows and chauris (a cross between yaks and local hill cows). An excellent source of protein, people throughout the Himalayan region, including Tibet, Darjeeling and Sikkim, and Bhutan, love this hard-to-chew cheese.\nHowever, chhurpi is now a favoured food for dogs in the United States and Europe:\nYeti Dog Chew is an all natural and delicious dog chew made with the goodness of Himalayan yak milk.These are a perfect option to keep your dog happy and busy for longer hours in a safe & natural way.Check out our website to see different sizes of chews available for your dogs ? pic.twitter.com/RvVy2pffZl\n— Yeti Dog Chew (@YetiDogChew) August 16, 2019\nAccording to the Nepal government’s Trade and Export Promotion Centre, in the fiscal year 2017/18, the country exported more than 800 million Nepalese Rupees (US $7 million) worth of chhurpi. According to local businessmen, about 60-70 percent of the chhurpi exported as dog chew to the United States and Europe is produced in the Ilam district itself.\nPeople love to chew chhurpis cut into small pieces. Photo by <PERSON>. Used with permission.\nMost cheese varieties tend to be soft, how do they harden this cheese? After collection, the milk is boiled and the fat removed. They then separate the solids from the milk, wrap them in a jute bag to squeeze out the water from the chhurpi, and dry it by putting it out in the sun or by hanging it over a fire.\nGodawari International Private Limited, which exports chhurpi as dog chew to India, Japan, Taiwan, Canada, and the United States, explains its rigorous manufacturing process:\n[…] Once the milk has cooled down, it is treated with 10 ml of lime juice and 10 mg salt for about 100 gallons of milk. The sour of the mild acid coagulates the milk and the salt speeds up the process. The solids are then separated using a burlap sac [sic], which is washed several times using warm water to remove the whey, and any hints of salt and lime juice.\nThe solids in the burlap sack are then subjected to squeezing for about 3 weeks when the cake obtained contains at most 5% moisture.", "447" ], [ "The cakes are pressed using weights to remove the excess moisture.\nThe cake is then cut to size and prepared for cooking [sic] under the sun and smoke[d] for 2-3 months. […]\nTwo chauris resting at a highland meadow in Nepal. Chhurpi is made from the milk from yaks, cows and chauris. Photo by <PERSON>. Used with permission.\nThe idea to market chhurpis as dog food came from brothers <PERSON> and <PERSON> who, together with <PERSON>, started the company Himalayan Dog Chew in 2003. The idea was sparked when one of the brothers noticed a dog gnawing at a chhurpi. In 2007, they launched their product at a pet fair in Bellingham, Washington. Since then, the company has come a long way: it is currently the largest exporter of Himalayan cheese out of Nepal, employing more than 9,000 people. In 2015, these three Nepali entrepreneurs appeared on the popular American TV show Shark Tank, even though they were already making over US $5 million in sales a year.\nMany other companies have since followed their lead, but Himalayan Dog Chew has now diversified, evolving from a single product-oriented business into a full pet supply company. According to its website, the company now proudly partners with a third-generation dairy farm in Washington State, which produces 10 million pounds of milk per month and over 124 million pounds per year, all for Himalayan Pet Supply.\nSince this hard cheese is being exported to so many countries, including Canada, Germany, Hong Kong, India, Israel, Japan, Korea, Malaysia, Russia, Singapore, Taiwan, Thailand, United Arab Emirates, the United Kingdom and the United States, its manufacture has become a regular source of income for Nepal's rural farmers.", "365" ], [ "For Stunning Glimpses of 20th-Century Nepal, Check Out ‘Nepal in Pix’ on Twitter · Global Voices\nPorters carrying the first car to the Kathmandu Valley. Image via Twitter/NepalInPix\nThroughout history, Nepal has represented a land of mysticism to travellers from abroad. Nepal’s high Himalayas with the world’s highest mountains, the mid-hills and valleys abundant with rare rituals and traditions, and the southern plains with dense forest and wild animals have always attracted curious visitors to this landlocked country.\nThough Nepal is not untouched by modern development, images from only few decades ago take you to a different world. The Twitter account Nepal in Pix publishes images from that era, providing an idea of what life was like not that long ago.\nTo start with, here’s an image of Nepal’s Public Service Commission (Lok Sewa Aayog) examinations, the mode of entry into government jobs, being held in open fields in the Lamjung District of Western Nepal.\nNepali youths giving Lok Sewa Aayog exams on a sunny chaur in Lamjung in 1975. #Nepal pic.twitter.com/0S8hoo8bcE\n— Nepal In Pix (@NepalInPix) May 1, 2016\nThe television set was a rare item in the 1980s. This image shows young men with a television, posing for a picture in the alleys of Kathmandu Valley.\nYoung Newar men bringing home their first TV, in 1987. #Nepal pic.twitter.com/3GCxe07lwV\n— Nepal In Pix (@NepalInPix) May 10, 2016\nIn the 1960s, hippies frequented the Kathmandu Valley. Marijuana and hashish was legally sold here and even a street near the Kathmandu Durbar Square was named ‘Freak Street’.\nगाजा र चरेस येहा पाइन्छ | Marijuana was legal in Nepal during 1960's. pic.twitter.com/6NVkVJ0Q3D\n— Nepal In Pix (@NepalInPix) April 22, 2016\nThe below image shows how the party scene in Kathmandu looked like in those days, depicting the fashion trending among young people:\nTime to party like it's 1969.", "206" ], [ "#Nepal pic.twitter.com/KV3YLAKq9D\n— Nepal In Pix (@NepalInPix) April 21, 2016\nWhen monarchy was at the helm, the king and queen were considered a beacon of hope, and people waited in long queues to get a glimpse of the rulers.\nPeople waiting for the arrival of the king & queen at Jumla Bazaar in 1978. #Nepal pic.twitter.com/ryyz2P0ROz\n— Nepal In Pix (@NepalInPix) May 4, 2016\nThe New Road leading to the Kathmandu Durbar Square in the heart of Kathmandu was really new with very few vehicles around.\nNew Road, Kathmandu 60 years ago. #Nepal pic.twitter.com/u98IQ3mMhM\n— Nepal In Pix (@NepalInPix) May 8, 2016\nCars, the possession of rich and powerful, were rare for the general public and so were the car dealers. The below image shows one such car dealer:\nVintage cars! The Ford car dealer at Lazimpat, Kathmandu in 1930s. #Nepal pic.twitter.com/XL3Ioi6u0G\n— Nepal In Pix (@NepalInPix) May 6, 2016\nWhile the Kathmandu Valley was advancing towards modernization, the southern plains was still a dense forest and a haven for hunters and guests of royal families. The below image is from one of the historic royal hunts with British royals as guests – killing several wild animals.\nKing <PERSON> with the day's kill in Dec 1911. A total of 39 tigers, 18 rhinoceroses & 4 bears were killed. #Nepal pic.twitter.com/aLjGeBe4jR\n— Nepal In Pix (@NepalInPix) April 30, 2016\nThe <PERSON> clan of prime ministers held power in their hands for almost 104 years until 1951, reducing the <PERSON> kings to figureheads during their rule. For their part, the <PERSON> dynasty's rule came to an end in 2008. Here’s an image of Prime Minister <PERSON> with his brothers.", "765" ], [ "Nepal’s only folk musical instrument museum is struggling to save rare instruments · Global Voices\nNepali Folk Musical Instrument Museum at the premises of Tripureshwor Mahadev Temple in Kathmandu. Image by <PERSON>. Used with permission.\nWhile the roundabout in Tripureshwor, Nepal sees traffic throughout the day, just a few minutes walk from the bustling road is the quiet and calm Tripureshwor Mahadev Temple, one of the largest temples in the Kathmandu Valley. Within the premises of the temple is a lesser-known museum housing rare Nepali folk musical instruments collected from across Nepal. Despite the cultural significance of the museum's collection, it is currently embroiled in a legal battle to keep its doors open to the public. If the founder of the museum loses the case, he’ll need to move the museum to another place.\n<PERSON>, founder and curator of Nepali Folk Musical Instrument Museum. Image by <PERSON>. Used with permission.\n<PERSON>, the founder and curator of the museum, has been collecting the musical instruments since 1995 together with his wife <PERSON>. His passion has taken him to all 77 districts of Nepal, and of the existing 1350 different types of folk musical instruments, he has collected 650. He either purchases old instruments that are not in use or commissions locals to make new ones. “We never buy the musical instruments that are being used in the villages,” he said talking to Global Voices. “If we take away the instruments in use what will they play and how will the tradition continue?”\nEls #dillunsllegim! En aquest llibre de <PERSON> hi trobarem més de 360 instruments musicals de #Nepal, explicant el seu origen, com estan fets i com es toquen. pic.twitter.com/PhR3rCcNQV\n— Museu de la Música (@museumusicabcn) September 17, 2018\nIn this book by <PERSON>, we find more than 360 musical instruments from #Nepal, explaining their origin, how they are made and how we can play them.\n“Our folk musical instruments are very simple,” he added. “They are made from whatever is found in the surroundings, and the music is inspired by the sound of waterfalls, the blowing of the wind, the mooing of cattle and chirping of birds, among others.” And nature influences the shape of instruments as well. For instance, some of the instruments resemble the locally found harro (black myrobalan), Rudraksha seeds (prayer beads), barley grains and even a tail of a cow. Hiti Manga, a musical instrument designed after the water spouts found in Kathmandu, produces music that resembles water being filled in a pot from a spout.\nHowever, all is not well with the museum. The displayed musical instruments are in bad shape and the museum itself receives only a handful of visitors, predominantly researchers on ethnomusicology. Adding to his woes, Kadel has been asked to vacate the premises by the Guthi Sansthan, an independent institution entrusted to take care of and conduct religious, cultural, and social heritage of the country. According to reports, the Sansthan has agreed to lease its property to the Kathmandu University and the latter is planning to house its music department there.", "765" ], [ "Kadel has filed a petition against it with the Kathmandu District Court.\nWhile the legal battle continues, <PERSON>’s team has been busy documenting and digitizing Nepali folk music. “We’re expecting to hand over the museum, registered as a non-governmental organization (NGO), to either the Government of Nepal or the Tribhuvan University,” he said. Though he will need time and money to move the museum taking care of the delicate instruments, he is hopeful that he will not need to do that.\nHere is a look at some of the rare folk musical instruments showcased at the museum:\nMurchunga. Image by <PERSON>. Used with the museum's permission.\nBinaayo. Image by <PERSON>. Used with the museum's permission.\nEk-tare. Image by <PERSON>. Used with the museum's permission.\nJor murali. Image by <PERSON>. Used with the museum's permission.\nPungi. Image by <PERSON>. Used with the museum's permission.\nDharma dandi. Image by <PERSON>. Used with the museum's permission.\nMadal. Image by <PERSON>. Used with the museum's permission.\nNekku. Image by <PERSON>. Used with the museum's permission.\nRanasinhaa.", "765" ], [ "A conversation with <PERSON>, one of the last speakers of a dying Nepali language · Global Voices\n<PERSON>. Image by author.\nFor years, people knew very little about the Kusunda language of western and central Nepal. The 2011 Census conducted by Nepal’s Central Bureau of Statistics puts the population of Kusundas, a forest tribe of western Nepal, at around 273. To learn more about the language and the culture of the Kusunda people, Global Voices spoke with <PERSON> — one of only two fluent speakers of the dying Kusunda language.\n‘The kings of the forest’\nIt was hot and humid, the roads were empty, and not even the battery-powered Tuk-Tuk drivers were willing to offer us a ride. With heavy tripods, cameras and other filming equipment, we headed to <PERSON> house in Kulmor village in Nepal’s Dang district. <PERSON>, in her early 80s, is one of the only two fluent speakers of the dying Kusunda language. The population of Kusundas is believed to be 273; however, field studies by researchers have shown only 150 of them dispersed in the Dang, Rolpa, Pyuthan, Arghakhanchi, and Surkhet districts of Nepal.\nKusundas have settled in villages after their forefathers spent their lives in jungles and caves as nomadic tribesmen. They would visit the villages only to beg alms, and many Kusundas still feel embarrassed to reveal their surname as they are still treated as ‘people from the jungle’. However, nowadays they have taken Thakuri surnames such as <PERSON>, <PERSON>, and <PERSON> — surnames connected with the ruling clan of Nepal. Kusundas claim themselves to be ban rajas, the kings of the forest.\nRead more: Indigenous Nepali Language With Only Two Fluent Speakers Sees Pages of Hope in Newly Launched Dictionary\nKusunda language is an isolated language which means it is not related to any other languages in the world. Unfortunately, it is also defined by a younger generation, that has stopped speaking it — leaving the language to slowly fade out as the older generations pass away. Besides <PERSON>, her sister <PERSON>, in her early 50s, is another fluent speaker of the language from their community.\n<PERSON>, a researcher devoted to reviving the Kusunda language, also speaks Kusunda language. However, <PERSON> fears whether her granddaughter <PERSON> will ever speak her mother tongue and keep the tradition alive. When we met <PERSON>, she was busy peeling green mangoes together with her granddaughter.", "811" ], [ "She was teaching her granddaughter to peel, slice and dry the mangoes for future use but unfortunately, they were talking in Nepali.\n<PERSON> with her granddaughter. Image by author.\nNo hooves, only claws\nAs we started talking to <PERSON> and she started telling us about their culture and tradition, a stray cow entered the barn. She suddenly rose from her seat, climbed down the ‘lisno’ (a wooden log shaped into a ladder), and shooed away the bovine. When she returned back, she talked to us about Kusunda food habits. She said, “Kusundas avoid animals with hooves but love eating ones with claws.” They wouldn’t even touch cattle including goats and pigs. They would neither kill a deer nor eat venison which shows how they co-exist with nature.\nHowever, they love eating birds, a pheasant being their favorite. And the monitor lizard is their preferred hunt. It's so special that it has become a part of the bridal ceremony, as they need to present its egg, meat, clothes and of course some money to the would-be bride's family. If they can’t find a monitor lizard egg, the initial conversation can’t happen between the interested parties. And no monitor lizard meat means ‘no marriage’ at all.\nThe bag and the snare. Image by author.\nStill hunting and gathering\nShe then unpacked a tangled bulk of cords. The mesh of cords was a snare to trap jungle fowls and bag meant to carry the trapped birds. Made from cords extracted from wild creepers, the snare is called ‘aant‘ and the bag is called ‘aamji‘ in Kusunda language. The Kusundas tie the snare between two trees, hide nearby and make sounds like pheasants by putting cycas leaves between their lips. As the birds pass through the trees, they get trapped and then they catch and carry those birds in this bag with perforations.", "811" ], [ "Ancient Pond Reconstruction in Kathmandu Stirs Preservation Protests · Global Voices\nRani Pokhari pond before the 2015 earthquake. Image by Flickr user <PERSON>. CC BY-NC 2.0\nPonds in the Kathmandu Valley and the southern plains of Nepal have always been an integral part of culture and tradition. While some ponds have been preserved well in the valley, others have been encroached upon by modern construction or have disappeared completely due to negligence by authorities.\nRani Pokhari, ‘the Queen’s Pond,’ with historic Balgopaleswor Temple in the center, has been drained off to allow for the temple's reconstruction. Authorities decided to renovate the pond as a whole after the temple was partially damaged by the disastrous earthquake of 2015.\nNow, activists and locals of Kathmandu Valley have come together to save this ancient pond in the heart of Kathmandu:\nकेही वर्षमा हामीले रानीपोखरीको यो हविगत बनायौं। एउटै स्थानबाट खिचेको दुई फोटो। #बाँदरको_हातमा_नरिवल। pic.twitter.com/9TLKxSDbMy\n— <PERSON> (@brazeshk) October 21, 2017\nIn few years’ time, we did this to <PERSON>. Two photos taken from the same point.\nThe beauty and historical significance of <PERSON>\n<PERSON>, a 17th-century heritage site, is believed to have been built by King <PERSON> in 1670 AD to console Queen <PERSON> who was saddened by the death of her youngest son.\nThe Balgopaleswor Temple in the center of the pond opens up to the public once a year when people with no siblings visit the temple during Bhai Tika, the ‘festival of brothers and sisters,’ on the final day of the Tihar festival, a five-day Hindu festival of lights.", "765" ], [ "The pond is also open to the public for the Hindu festival Chhath.\nView of <PERSON>, 1919 pic.twitter.com/TQKKSGvTaf\n— Nepal In Pix (@NepalInPix) December 7, 2017\npic.twitter.com/EGUWZ4NhA0\n— Old photos of Nepal (@oldphotosNepal) January 10, 2017\n<PERSON>. Old is Gold: Rani Pokhari before 1990's (Bikram Era) earthquake\nKnown for its beauty and historical significance, the pond is surrounded by Ghantaghar (the clock tower) and Trichandra College, Nepal’s first campus in the east, and Durbar High School, Nepal’s first high school in the west. On the southern bank lies a statue of King <PERSON> and his two sons riding an elephant. Temples dedicated to Hindu gods and goddesses stand at all four corners.\nControversial, messy reconstruction\nThe reconstruction of the pond has been a bone of contention between the government's Department of Archaeology, local people and the Kathmandu Metropolitan City (KMC) looking after the task. Construction work on the temple was halted when activists protested against the use of concrete materials by the contractor.\nThe row resurfaced after the contractor started building a concrete wall around the pond:\nThe KMC says it wants to “beautify and modernise” Rani Pokhari, complete with a son et lumière fountain, a park and coffee shop. This violates Nepal’s Ancient Monument Preservation Act which says historic sites over 100 years old have to be preserved in their original form.", "765" ], [ "Nepal’s Vulture Restaurants Are Helping Revive Their Population and Generate Income for Communities · Global Voices\nHimalayan Griffon at Vulture Restaurant, Nawalparasi, Nepal. Photo by <PERSON>. Used with permission.\nThey are big, ugly, and have a bad reputation. Although vultures have been at the center of a love-hate relationship with humans — they are also our natural allies. Vultures are mostly carrion eaters and are a major part of the natural process of death in the wild. By devouring large amounts of flesh, these large birds help limit the spread of bacteria and disease that can otherwise spread from the decaying animal bodies. However, despite their important role as buffers against the potential spread of illnesses, they are often regarded as more of a pest than an important bird.\nAs a 2007 survey in India shows, the population of oriental white-backed vultures (Gyps bengalensis) had fallen to 0.1% of its numbers in the early 1990s. In 2009, western Nepal saw its population of oriental white-backed vultures fall by 25% since 2002. Likewise, the population of long-billed vultures (Gyps indicus) and slender-billed vultures (Gyps tenuirostris) also declined drastically throughout the Indian subcontinent. Unfortunately, this trend is not only happening in South Asia, vulture numbers are decreasing worldwide due to less food availability, collision with man-made structures, and poisoning among others.\nTo combat this decline, some countries have proposed an interesting conservation plan to bring their numbers back up — Jatayu restaurants, or restaurants for vultures.\nA restaurant for vultures managed by communities\nTo conserve vulture populations, vulture feeding stations have been set up in a number of different Asian countries such as Cambodia, India, Pakistan and Nepal.", "447" ], [ "In Nepal, the feeding stations are managed by the nearby communities and have been dubbed Jatayu restaurants, named after the revered character in the Hindu epic Ramayana and the vulture’s Sanskrit name, Jatayu.\nIf you are in Nepal & a wildlife enthusiastic, visiting Jatayu Restaurant will be an experience of lifetime. I was mesmerized. #conservation https://t.co/rENmDgrkkE\n— <PERSON> (@_Re_be_cca) August 3, 2017\nThese restaurants source old and unproductive cattle from farmers and take care of the animals until they die at the animal old-age center. People happily handover their old, unproductive cattle to these restaurants because the animals are well taken care of at the end of their lives.\nA scene from a vulture restaurant in Western Nepal — dead animals are offered to vultures at this site only after ensuring that the carcasses are free of Diclofenac. The vultures had been disappearing owing to the use of this medicine for treating livestock. The vulture numbers were on a decline since the poor birds died of kidney failure after eating Diclofenac laced carcass. After the introduction of these restaurants throughout Nepal's southern plains, the vultures are returning back. And the conservationists are happy! ———- #vulture #vulturerestaurant #diclofenac #vultureconservation #terai #Nepal #conservation #jatayurestaurant #southasia\nA post shared by <PERSON> (@sankuchy) on Oct 4, 2016 at 11:16pm PDT\nWhen these cattle die, they are fed to the vultures — but only after they are tested to ensure that the cattle are diclofenac free.\nDiclofenac, the killer drug behind the mass deaths of vultures\nThe use of diclofenac to relieve pain in livestock had been one of the major causes of mass vulture deaths in Nepal, India and other South Asian countries. Even small doses of diclofenac can be fatal for vultures, causing kidney failure in these birds. As the kidney fails to function, uric acid accumulates in the birds’ blood and crystallizes around their internal organs.\nSince vultures feed in large groups, a single carcass laced with diclofenac can cause the death of scores of vultures.\nThe drug was banned in India, Nepal and Pakistan in 2006 and in Bangladesh in 2010.Thanks to the drug ban and also to conservation initiatives by several organizations including local communities, these ‘critically endangered’ bird species have started to bounce back.\nIn addition, these vulture restaurants have become tourist attractions which draw in both domestic and international visitors, providing nearby communities with an additional source of income.", "447" ] ]

[ 7878, 8906, 11038, 735, 1160, 4632, 1950, 9262, 7610, 7196, 7559, 6000, 8065, 5350, 54, 346, 781, 216, 10789, 3899, 11381, 661, 7892, 10260, 1735, 8963, 1936, 4612, 4195, 10369, 4079, 6918, 6009, 6086, 11418, 5101, 6778, 9417, 5789, 3778, 1102, 10171, 1856, 3022, 6077, 8014, 11408, 3698, 850, 6012, 5443, 6411, 3874, 1322, 3427, 10195, 3264, 9280, 2975, 2769, 8204, 883, 10212, 7795, 8590, 5111, 7275, 6314, 4876, 3262 ]

[ [ "Build a university/engineering school\nAs many answer have pointed out, building a gun from scratch in the bronze age will be very difficult. Thus to solve this you should not try to build a gun, but build a society that can create a gun.\nSo in your backpack bring knowledge, USB sticks with encyclopedia and all textbooks you can get your hands on from primary to university grade. This should not take up a lot of space. Bring 4 laptops with the devices to charge the laptop, solar panels and converters. Bring enough to have some spare. Bring some actual guns for protection from the locals if necessary and to impress them. Last and most important bring detailed start up plans and tools. Since it is the bronze age, I would suggest bringing steel axes and saws, hand drills and if still room left maybe steel screws for easy construction. Also fill the rest of the bag with gold/silver/diamond or whatever currency the locals use. I am assuming a rather large bag pack, but you can reduce all number to one (2 for the electronics) if it does not fit.\nOnce you arrive in the past you need a place to settle and build your university, convince the locals that your knowledge is worthwhile and get as many pupils you can support. If you can choose the place you land make sure your near coal, ion and oil deposits. A place with some kind of states already in place might be best, see: Bronze Age States, but you might also opt for advanced framing cultures. The hittites empire might be a good place to locate (modern Turkey, Anatolia), near lake Van seems to have all the necessary resources, I just don't know how far underground. Resources: metals, oil and coal.\nOnce you arrive roughly follow the next steps:\n1. Sell you knowledge for food/influence. Best knowledge to sell is probably improving tools (mainly agricultural) and health treatments. Distilling alcohol might also be a viable option or construction work.\n2.", "222" ], [ "Build/Buy a house/school and build a printing press. Start printing the correct books for the school. So learning how to read, simple arithmetic and than basic engineering principals. All in a very directly applicable manner.\n3. Start gathering and teaching pupils and spread your influence. Do this by helping the local community and state community and let your pupils do projects.\n4. Start building a foundry inside your school and start making bronze tools. Don't overlook the fact that you probably can improve their bronze making a lot. Being very valuable, also you can teach/use local bronze smiths to speed up you foundry.\n5. If no iron is available make a project of building one, you need to have the exact location of easily accessible iron available. Remember that you only need small amount, so no need to look for the very big mines of nowadays.\n6. Progress from bronze to making iron tools\n7. Later progress to weapons and a weapons factory.\n8. If oil is available one might make plastic in a very early state. Making some kinds of plastic is not that hard and has very good material properties for tooling compared to the wood that they would normally use.\nThis plan will take quite some time and in the mean while you need to make sure that both the local and state community are cooperative and appreciative of you. Building a society by cooperation is probably easier that force, but make sure you have enough force to withstand outside pressure. Have better weapons and tactics should allow you to withstand a lot of pressure if necessary.\nTo speed up the whole process supplying the state with better weapons and tactics than the enemy can boost the whole procedure of creating a weapons factory. In that way you could start with a primitive weapons factory and gradually upgrade to a modern one.", "222" ], [ "How could a monarch rule in a vast, isloated, medieval city\nThe City itself\nLet's assume we have a city of the size of the Peloponnese (round about 22'000 square kilometers) which is very dense populated (by medieval terms) and is isolated from the rest of the world (think of something like an ocean surrounding the island). The city wasn't 'planned', it just grew bigger and bigger so the city layout itself is a bit flawed (e.g. bad street layout). Let's for simplicity assume there is enough food for (nearly) everyone.\nThe Population\nAll citizens use the same common language, although many dialects do exist. Nevertheless it's a multi-ethnical population with different religions an different customs. Sometimes the tension between these different culture groups leads to nasty crimes but all in all the situation could be considered as stable. Wealth is distributed pretty bad (as usual) but there is no particular cultural group having a much greater share of wealth than the others.\nThe Government\nNow that’s the questions. I'd like to have a central ruler sitting right in the middle of the city. Given the size of the city, a direct rule however is deemed to be impossible. Therefore, a greater deal of decentralization appears to be required.\nIdeas so far\nFeudalism\nThis is the first thing I had in mind: Have a single king with multiple vassals, which in return have multiple vassals themselves. You get a high decentralization with an acceptable control from the central government/ruler and you get a decent degree of stability. Feudalism also allows for some interesting storylines regarding counts, bloodlines and similar stuff. There are some fatal problems though...\n* Feudalism was built on an agricultural society. The lower vassals had a large mass of peasants beneath them. Feeding people was hard so agricultural land was expensive.\n* Feudalism needed a constant change in borders. The liege gave its vassals land in return for favors or good work which the vassals children inherited on death. Works fine until you got no more land to distribute. I'd like to dispose the idea of the civil war emerging every 100 years because the vassals get greedy for more land or the idea of extreme balkanization of the city until every citizen is a landlord himself.\n'Mayorism'\nThis approach features more bureaucrats and fewer nobles.", "878" ], [ "Each district has a mayor and a smaller council designated to govern the pile of land he's been assigned with. A mayor is not of noble blood but excels in administrative skills. Each mayor may rule until death, after which he is replaced by any other administrative professional from anywhere, or until another person has been assigned to do his job (because the former mayor was incompetent, corrupt or....). There are no elections for the mayor as we don't want the citizens to get a taste of democracy and get uppy against the crown-authority. Up to this point the system would prove pretty stable, but here are some problems:\n* The king most likely has better things to do then to assign each of his thousands of mayors day to day anew. Like in feudalism he'd install multiple layers of administration, that in the end a group of let's say 10 people assign the jobs for him. This would then lead to a concentration of power in the hands of very few people which in return could get come to the conclusion a council of ten people is better than a single king.\n* Bureaucracy was on the rise late 17th or early 18th century which is clearly not an option for a medieval based setting. Writers in ancient Egypt did a similar job and different empires had different people doing the same job too, but all of them used a more or less centralized approach. Using common people for administrative jobs became fancy after bourgeoisie was on the rise and enlightenment was more widely accepted.\nEDIT\nAs there were many question regarding the city. First of all, it’s a fantasy setting. The size is absurd, but that’s what it’s all about and that’s why it’s interesting in the first place. No some answers:\nUnderground caverns/tunnels\nGet yourself some underground cave system with some tasty mushrooms and some solid building material to mine. If you’d go crazy you could use your poo to fertilize the mushrooms and build underground farms etc. but I’d rather like to keep the details out of here. Just dig down, eat mushroom and be happy. One could also dispose corps into catacombs. The risk of plagues a heavy disease is still high, but on the other hand side a city of that size probably won’t be a nice place in the first place. Constant mining may also lead to parts of the city to collapse into the depths below, requiring the city to be constantly being renewed.", "222" ], [ "Completely depending on the aliens\nWith the exception of your last option, the options are all completely based on human politics. I doubt the aliens will be very interested in human politics and will have other needs for their embassy. You don't discuss the location of you new house with your pets, maybe consider their feelings but they don't have much say in it.\nSince you are talking about different alien races the first choice would probably be places were they feel comfortable. Assuming they don't need complete hazmat suits. The cold aquatic aliens will want to be close to the poles, warm aquatic, Mexico bay or the Mediterranean. Jungle aliens in Brazil or Africa, and so on. If they only can build one spaceport probably the most influential alien race determines the location.\nSince they come to earth, for them it would be relatively easy to fly around the planet very fast. (Assuming they have unlimited free energy ,water and nuclear fusion is enough for that).", "197" ], [ "So you can build many stations and don't have to be close to urban population.\nThere is a good chance we humans smell terrible or are very ugly and they don't want to be in our constant presence. Also walking around in a city might not be very nice for them. They will get huge amount of attention and mobs around them. But also the size and shape of our infrastructure might be horribly wrong for them. An elephant sized octopus like alien that uses suction for locomotion might not like our tarmac that much. Also a tiny alien will have a constant fear of being trampled in big cities. Let alone the amount of walking he would need to do to get somewhere.\nSince no natural resources are of any importance to them and also assuming biological resources are not of any importance, the only reason they come here are for the humans. So maybe the art, politics or just curiosity.\nAnswer: So my best bet would be that they build spaceports close to human urban population but far enough away not to be bothered by them and in the best suitable bio sphere for them.", "197" ], [ "The problem here is that you are looking for one currency. And that you are looking for currency.\nWith the society you describe, there is little pressure towards it. There is almost no trade beyond the community level, and the existing trade will be mostly local.\nAt community level you actually don't need much currency; rural communities in \"developed\" countries like England and France in the 16th, 16th and 18th centuries would sheldom use money except for \"imported goods\" and taxes (and a part of taxes would be in locally produced goods). You remember who took three cabbages from you yesterday, so you go today to his house and ask for half a chicken. Playing the system (failing to pay debts, for example, or claiming debts that don't exist) is very hard in small, closed communities.\nAdditionally, such small communities won't have much to trade. Survival will take most of their efforts, and whatever surplus they can get is probably not very different from town to town.\nHistorically currency1 developed because:\n* A way of certifying the quality of the bullion in the currency.\n* A show of sovereignty; the first thing new kings (and claimants to the throne) would do was to mint money with their name/likeness.\nLacking a strong authority able to back it2, there are many hurdles to any proposal. In some areas your proposal may be so abundant as to be meaninless, in others too scarce. If there are big differences between areas (as your example of a tribe settling in Fort Knox) the people in worse off areas may refuse it (why give the effort of a year of work for what, to someone else, is just getting into the vault and getting an ingot?3).\nWith that said, an unified currency is not a necessity. You may have different currencies in different areas, with some interchange rates that are variable depending of the situation.\nA significnt alternative for local trade could be credit based in an honor system; if a trader went to town 1 to sell A but there was nothing interesting to him there, a person of authority there could buy A in exchange of a letter (or simply a verbal agreement!) so the trader could go to town 2 and get B from another local authority (who could then ask payment in whatever town 1 could offer).\nAnd, last but not least, the need of survival would make a currency based system very dangerous.", "130" ], [ "So you have a good harvest and get your boxes filled to the rim with (let's say) floppy disks. Good, you are the top dog of your village. But next year there is a drought and everybody harvests are poor. Since floppy disks are not edible, nobody gives you a single carrot for all of your savings. Since there is no honor/community system protecting, you are left to starve.\nNow, in the town next door, they do not use currency but they store the food surplus. When the surplus is extra (you have your stores full with last year harvest, and this year harvest is near and will be plentiful) you may exchange some of it for other goods. If the harvest is bad, you just eat your savings.\n1 Please be aware that I am talking about currency and not about bullion (e.g. raw slumps of gold and silver).\n2 And that needs currency in order to manage their taxes and budgets, because it is the only significant group of people working to grow their own food.\n3 And now you are thinking \"But the people in Fort Knox may keep it a secret\". Well, no, because they will begin using their gold instead of farming/producing gooods and people around will know that there is something fishy, even if nobody talks about the vault.", "130" ], [ "Early Space Race Era\nI agree it can be doable (with a lot of luck) at steam power era but will need a massive effort akin to put the man on moon, maybe even requiring a international task force. Below I will list some challenges were are not pointed in previous answers.\nWhy not in the age of sail?\nBecause we never got an age of sail for start. At sec XV we unified some kingdoms and they started a tech race akin to the space race to finally develop oceanic navigation. At sec XVI we founded colonies in the new world and it pushed the navigation development and with the growth of the colonies culminated in the \"Age of Sail\". Without those elements OP super earth most likely skiped it entirely.\nA Fearsome Sea\nThe size of this Ocean will bring a lot of weather and climate challenges. You can expect winds, tides and currents to be way bigger. Also expects typhoons to be cataclysmic. The tides per se will be a good challenge for the building of ports. The tsunami size weaves can make even fishing impossible in large coastal areas. The sea conditions will be nasty, even in good weather and impossible in bad weather. Navigation will be a really dangerous business. Also the sea conditions will make coastal erosion a thing. I ever wonder if most of coastal will be of massive cliffs.", "308" ], [ "All those factos summed make me wonder coastal cities will be almost entrenched in big natural harbours and important sea trade routes will be exclusively between cities in bays (the only place where is possible to build a big port anyway) and where the route travels along a, most time, very peacefull chunk of the ocean.\nLots of Trains & Planes but no Fleet\nThe size of the continet this points out railroads will be in demand early ans planes too but navigation will be very limited in all aspects, speacially in tech. This leads to a strange scenario where we will hit industrial age and even space age skipping sail age.\nThe Dark Side\nThe Moon is a great target for mankind aspiration, from dawn of time we can see it but we cannot reach it. We dreamed to land here a million times. But what if for millenia we do know Super-Terra has a dark side out of reach? Once scientist proves we can launch a object in orbit and retrieve it the first thing to be flung out will be a camera to take pictures of the uncharted lands. Once the first pictures are retrieved be sure it will trigger a space/exploration/colonization race.\nAge of New World\nThe reason the new continent will spring a sort of space race is to gather data from the land, not only a coastal line but weather a major biomes, moutains ranges, rivers. Everything necessary for future settlers. Also a new tech race on navigation will sprung. Visionaries will dream of under-water-boats, starting the project of the (probably first) submarine. Long-range-any-weather-transocenic ships will gain the status today we grant to a mission to Mars. It will bring a new age.\nWhat if there already people here? They are probably in another phase in tech development, even using a different \"tech tree\" but fact we reached them first. Also yes its unlikey but possible small grups can end strained here but OP can wave a complex geologial/ice age to explain it. Maybe thermals isles of heat making a sort of ring of fire connecting boths continents in immemorial times. What in that case the answer instead can be Ice Age", "99" ], [ "First of all. Let me make some basic assumptions. I will assume your world will consist of mostly ocean. I will also assume that there are many continents roughly the same size that we have on earth. That will mean an awefull lot of continents. Furthermore I will assume that your humans evolved on this world.\nEvolution One light year means that on with a speed of 1km/h one would need 1 billion years to cross the planet. With this speed a species that reaches the other side of the world would have evolved into something completelly different by that time.", "258" ], [ "This speed would also mean that even if we assume life starts at one place by one billion years life would be everywhere.\nProbably live would move to each continent separately, but nearby continent would influence one another.\nIntelligence Intelligent life could evolve on many of these continent. But it would still be unlikely for two species to evolve to intelligence at exactly the same time on neighbouring continents.\nLooking at human evolution it appears that we could not cross any oceans until quite late in our evolution. The americas where only settled 40000 years ago. That means that for most of its evolution sentient life will be bound to only a few continents.\nOnly after devoloping ships will people discover the other islands. Note that by that time the people will propably already have developed an advanced culture.\nFrom there a culture can spread across the rest of the world at a relative slow speed. In our society it took only a few centuries from there to developing modern communication technology.\nEffects This would mean that each civilization has a mother continent from where it originates. Politically people further away will become independent from their mother continent. However it would be unlikelly for them to lose all communication with their mother continent.\nSome information of general interest (scientific for instance) could well spread very wide, but a lot of information will probably be only of local interest and people on other continent would not be interested in them.", "335" ], [ "Practical aspects: It seems to be agreed that the jar + Burning Plant idea is really difficult to be set up.\nWhy not separate the combustible from the activator? I will take a few concrete examples, but feel free to replace them with items from your world:\n* Matches are the activators (could be a chemical product stored in glass)\n* Coal is the combustible (could be an GMO)\nThis could help you to have a system of coins and bills or something, since the two products are used together to burn things With this principle you also ease trades (matches are lights, and it is easy to spare them, and to give change)\nMarket aspect:\nA currency has a value, this value is based on another product: for example € with gold (If you have several countries and currencies it’s more based on the exchange rate and interest rate) So your currency should have a reference, something valuable which should not fluctuate too much.\nBut here you want to use a consumable as currency which means that its value will depend on the value of your chosen “valuable product” and the amount of your currency available (remaining matches in your country for example).\nHow do people earn these matches ? Is it an universal income ? How many matches are consumed by people per year? How many matches do you need for survive per year? How many matches are you earning each year? How much is it fluctuating during the year? (consuming/earning rate)\nThose questions will help you determine your currency fluctuation, but also to determine the real impact on the market (inflation and deflation)\nYou can imagine that the value of coal will decrease in summer, and dramatically increase in winter. I would suggest to have durable matches to always have a stable amount of matches on the market: the amount of matches/coal should drop significantly in winter, if a match has a short lifetime then in spring there will be no resources left.\nThis is a real problem: if one match is worth one bread in summer, one match could equal ten breads in winter.", "130" ], [ "How do you really determine the value of your currency ? Keeping that in mind people will probably prefer to sell in summer and to buy in summer.\nSeparating the activator from the combustible (and maybe the combustive?) could introduce some new concepts: - You waste matches when failing the strike, and as matches are your daily money and the value is evolving, wasting a match in winter means losing a lot - People always want to optimize things, they will develop techniques intending to limit the waste of coal/match; - People will take risk in selling all their matches during winter and buying a lot in summer. - Poor people will buy the bare necessities of life selling there last remaining matches.\nHave you read the stormlight archive by <PERSON>? There are some similarities as they use glowing spheres as main currency, meaning they use it for light as well as money. These aren’t really combustible as they are rechargeable but the Wkipage could give you ideas https://en.wikipedia.org/wiki/The_Way_of_Kings\nEDIT: Hope this is better", "130" ], [ "I would drop the notion that your technology includes artificial gravity (beyond spinning) and engines that can get you to half the speed of light. Which as many point out limits time for the generations and leads to the problem of hitting stuff.\nI would assume that a spinning cylinder of a decent size with the interior designed to provide space, light and \"nature\" with the center axis being a source of light and \"rain\" and your vessel has decks below (outside of the inner space) that provide space for farming, then industrial tools, then storage and lastly the outermost deck would be flooded with water not only to protect the occupants from cosmic radiation, but also to make certain that the ship has enough water to make it across the vast expanse of interstellar space.\nI would increase crew/passenger size to 100,000 with an expected expansion to 300,000. I would also consider that the on board time between stars is about the same as the remainder lifespan of a 20-something first generation person. 50 to 60 years seems reasonable thus you would have grandparents who remember green hills, blue skies and a horizon that bent down instead of up.\n10% light speed tops makes a reasonable on board trip time. I'd go with something along ion engines, low thrust that continues for a very long time. Instead of turning the ship you would have thrusters that would point bow-ward at an angle, thus your deceleration time would need to be longer than your acceleration time. This way you can use both ice(s) plow/shield and a Bussard Ram Scoop collector to provide more fuel.\nIon thrusts are weak - 5.4 Newtons of thrust is the latest and most powerful ion engine. One can convert newtons to gravity... But I'm not doing it here.", "947" ], [ "I can pretty much tell you that you would be pulling .01 g which would hardly be felt and the spinning craft would have a greater force on people than the continual thrust.\nYour ship could get up to a decent velocity given lots of time, but a half the speed of light will bring way too many other technical questions to mind as previously explored.\n300,000 colonist/terraformer/ship builders arriving in a stellar system is a good start. One could argue that the ship is feeling crowded by this time so passengers and crew would be hungry for more space. And humans are real good at making new humans so 20-40 years at this new star system, given enough space, humans could be at the half million mark plus.\nThey would need to stay in that system long enough to make enough humans to fill two ships... plus leave behind enough colonists to make a new world, make more ships - what ever direction they want. figure another three generations of time (say 60 years) and 1.5 kids per parent - magically the human population is at or slightly above one million. To give you an idea of how fast humans can make more humans, just look at population growth from 1900 (1 billion humans) to 2000 (7 billion humans).\nSo yes, your basic idea makes sense. Humans making more humans, the desire to find new fresh untouched worlds to explore. Perhaps groups of like minded people are off to make their own worlds by their own rules...\nAs for size. Rendezvous with Rama might be helpful. Not only with size, but with interior design to handle space travel.", "947" ] ]

[ 7180, 4530, 3347, 7818, 9831, 8654, 10460, 10134, 9035, 8503, 8531, 5521, 9933, 11283, 5276, 1506, 2428, 11353, 142, 10161, 6764, 2764, 5186, 8028, 8683, 1894, 4725, 10922, 6733, 7470, 6419, 2364, 10478, 3930, 8179, 1019, 6955, 1403, 9966, 3968, 6024, 2244, 11053, 6620, 7685, 5648, 7928, 5566, 3214, 7095, 3505, 3466, 5378, 9365, 274, 2924, 4577, 5852, 10197, 4289, 8459, 1573, 4150, 6825, 856, 1217, 10605, 6316, 3009, 10072 ]

[ [ "<PERSON>\nlove the pink heart when you like the film.\nbarbie was super fun. i saw it at the cinema with (<PERSON>) & a bunch of other pink wearing fans!! our theatre was very responsive to this film often talking to the screen, clapping, cheering & just general laughter. this film was funny like it definitely had me on the floor cracking up. however, this film lacks confidence in what it’s trying to say or communicate to the audience. women. yes okay and what about women.", "657" ], [ "<PERSON> took white feminism & cranked it up in this film & i didn’t particularly like that part. i also didn’t like that the dialogue was so obvious at times. like they are letting you know what they know & that they know it.\ngorgeous gorgeous film like beautiful gowns down. <PERSON> and <PERSON> gave such amazing performances that will definitely define their career. loved the score & soundtrack in context with the story & i loved all the barbie’s.\nmy last complaint would be that it felt to short like they didn’t know where to end or how so they just ended it. felt like something was missing that’s was supposed to actually get me to connect to the story but alas it didn’t show up. just the barbie logo & the credits.", "577" ], [ "<PERSON>\n“but do you like me?”\nsobbed 4 separate times & i couldn’t even tell you why. when i first saw this film i was 18 years old just like <PERSON> in the end & i had the same wonders and curiosity about my future. my relationship with my mom isn’t that bad but there are times where i have wonder if biologically i wasn’t her daughter would she still care for me just the same.", "577" ], [ "i think what also made me emotional was the relationship between <PERSON> & <PERSON>. idk it’s just something about women being so tender & loving towards one another in that special bond type of way that just gets me. anyway lovely lovely film 🫶🏾", "883" ], [ "<PERSON> Behind\nif i attempt to write a serious review it would be quite sad as this film plays out events that are actually a probability here in america & with everything going on overseas it’s just the timing of this is just overwhelming.\nhowever <PERSON> is one of the most unique filmmakers we have & his direction absolutely captured the horror & devastation of the events that took place. i love him so much, his artistry pushed boundaries and defies the norm. i think the ending of the film perfectly encapsulates how for some people the only thing that matters to them is whatever they are dealing with.\np.s. if you’re familiar with mr.robot lore than i think you’ll love this!", "529" ], [ "Iron Man\n“you are a man who has everything and nothing”\nrevisiting this film after several years was a spur of the moment decision. i was craving a film with action but also with a lot of emotios + stakes. so i traveled back in time to when the mcu actually gave a shit about the work they were putting out into cinemas.\niron man is truly the best & most fantastic introduction film to an entire franchise universe. the tone in the beginning was one of serious accords, keeping you on your toes with just the right amount of dark humor to balance things out.\ni mourn the loss of phase 1 mcu films.", "457" ], [ "were they perfect ? absolutely not but they had heart, soul and actually made you think, should i give a fuck about this billionaire playboy with daddy issues? it presented us with the reality that life is never so black and white. it’s the grey areas that hold the most weight.\niron man depicts <PERSON> for exactly who he is. they present him to us in a way that you’ve formed any opinion only being 5 minutes into the film. but when you keep watching, you see a man who is conflicted, struggling with his beliefs that his father instilled in him and questioning if it’s something he truly believes. by the end of the film you get your answer in <PERSON>’s way reminding you that he’s still him but with a new outlook on life and tech.", "80" ], [ "The Hunger Games: The Ballad of Songbirds & Snakes\ni spoke to <PERSON> at the baftas red carpet around 2 years ago for a few minutes with my sister. i believe this was after west side story came out.\nshe’s honestly such a kindhearted girl and i’m so happy for her shining in roles like this. genuinely excited for her career in film! she elevated the character of <PERSON> amazingly.\n<PERSON> definitely stole the show though.", "577" ], [ "he captured <PERSON>’s character perfectly, and was such a reminder of how snow is such a chillingly fascinating villain. would also love to see what he goes on to do!\noverall, i cannot express how much i liked this film’s casting. i could honestly continue to give merit to other actors in the ensemble. my expectations were definitely met.", "657" ], [ "<PERSON>\ni do think it’s super cool and fun and awesome when big blockbusters are earnest to a fault and make me cringe a little (which is good!). like man you cannot tell me watching <PERSON> ride <PERSON> penis while she makes him read sanskrit so he can orgasm (while <PERSON> is watching at one point?) didn’t make you giddy.", "577" ], [ "i’m v anti “this doesn’t make sense” culture but also this screenplay does not make sense to ME on multiple levels. the one that truly matters is the fact that this is a character study and i still don’t know who <PERSON> is! he’s so flat! <PERSON> once again said any woman ever can’t cook all they know is scream, neglect their children, be an alcoholic, eat hot chip and LIE! idk. it’s pretty goofy!! fan fiction ass movie… big ROFL", "132" ], [ "The Five Devils\nundeniably an interesting movie with a fascinating premise; i can’t help but feel something was missing, though. it didn’t grab me like i’d hoped it would. i also cannot exactly look past how this was very much a movie made by white french people that didn’t quite know how to center its black characters, particularly the black queer woman who is supposed to be so formative to the story.", "236" ], [ "however!! i am definitely not the individual to be delving into that and there are surely better criticisms of that on this app—i have no interest in sounding like a white knight of film criticisms. my criticisms don’t take away from the fact that it was really strong performances all around (<PERSON> is always a gem, i love how much acting she does with her face) and some really beautiful interior and exterior shots. the mood of this whole movie was pretty well crafted, too.", "657" ], [ "Poor Things\n“i must go punch that baby.”\npoor things is a extremely strange story that leaves you in tears laughing but also shying away at the raw examination of people and feelings. it offers a unique and at times disturbing examination of what it means to be human.", "352" ], [ "it questions are current knowns and the boundaries we put on ourselves as people. it has the usual <PERSON> strangeness, but combine: with a <PERSON>-esque story, it’s absolutely thrilling.\n<PERSON> is absolutely stellar in this, and after watching it i can see the oscar for lead actress being between her or <PERSON>. which is gonna be a very exciting race to watch.\n2023 Ranked\n<PERSON> Ranked", "378" ] ]

[ 1878, 7786, 984, 3173, 10592, 10734, 4727, 8943, 3552, 1723, 11249, 1124, 4640, 2655, 8685, 591, 2956, 9594, 11049, 6973, 3538, 1299, 3821, 5600, 3343, 3249, 6856, 10093, 9699, 6791, 3429, 2642, 1186, 5128, 8488, 4229, 7324, 1785, 6774, 4747, 4588, 6153, 5043, 10957, 6908, 49, 28, 2053, 2693, 4126, 3626, 1517, 11402, 2084, 1898, 4330, 7861, 6888, 3697, 5705, 9085, 10567, 9622, 10455, 6619, 1635, 4690, 3583, 6808, 10777 ]

[ [ "As an Economic Crisis Grips Turkmenistan, the President Sings and Bikes · Global Voices\nA pop song written and performed by Turkmenistan President <PERSON> and two of his grandchildren is attracting attention after independent media outlet Chronicles of Turkmenistan posted video of it on their Facebook page.\nIt's not quite at the level of worldwide smash “Despacito”, but still some fans appeared to enjoy the music:\nГолос отменный, молодец, культурный досуг всем необходим, от песнм душа расцветает!\nA very good voice. Cultural leisure is necessary for everyone. The soul is enriched by this song!\nTurkmenistan has an abysmal human rights record and is experiencing a difficult economic situation, with unemployment and shortages of basic goods on the rise. But <PERSON>, who in February 2017 “won the hearts” of 97.69% of voters in the country's presidential election, prefers not to publicly say a word, instead propagandizing the “great achievements of the country and a successful life of his people.”\nMany of those achievements are his own: “Yadimda” (Turkmen for “I Remember”) is not the first number written and sung by the Turkmen president, and writing songs and singing are not his only talents.\n<PERSON>, deemed “one of worst world dictators” by the Foreign Policy magazine, is the author of more than 40 books on different topics. A work of his on tea last year, for example, was received by his compatriots with almost religious reverence:\nA dentist by education and a lifelong sportsman, he once forced his ministers to join him at the fitness club:\nAnd at the end of July, in anticipation of the country's hosting of the 2017 Asian Indoor and Martial Arts Games in September, the president took part in a bike ride that shut down private motor vehicle transportation in the capital.\nThe 60-year-old <PERSON> climbed to power at the very end of 2006 after his predecessor <PERSON>, who had been in power since its independence from the Soviet Union in 1991, died.", "148" ], [ "<PERSON>, who named himself <PERSON> (Father of Turkmens), fostered a personality cult around his rule. Among other things, he changed the alphabet in the country to the Latin, changed the names of the months (April was named after his mother), changed the names of the week (Saturday was changed after his spiritual book “Rukhnama”), and implemented many other eccentric ideas. His “Rukhnama” became the second sacred book for Turkmens after the Quran and everyone had to learn it by heart, while around 15,000 monuments of him, including several golden ones, were built around the country.\n<PERSON> poses during a 2009 visit with President <PERSON> and First Lady <PERSON>. Photo by <PERSON>. Public domain.\nAfter <PERSON>’s death, <PERSON>, whose official titles (that he awarded to himself) include “Leader of the Nation” and “Arkadag” meaning “protector”, destroyed the personality cult of his predecessor and built up his own.\nHis regime kept up the restrictions on freedoms. Turkmenistan is home to the world's fourth biggest gas reserves, and is suffering from a serious economic crisis – yet will soon host the Asian Games.\nGiven the context, a commenter under a January 2017 news clip on YouTube of the president singing criticized him:\nВот что бывает господа, когда у человека очень много денег и он пользуется богатствами и ресурсами страны в личных целях.", "146" ], [ "With Economy Unravelling, What Awaits the Turkmen Regime? · Global Voices\nPhoto taken in Ashgabat in 2007 by <PERSON>. Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.\nOn June 7, Turkmenistan's all-powerful president ordered a stripping away of the generous subsidy system that gives local people a reason — asides form fear — to tolerate their grandstanding, totalitarian resource-rich government.\nCitizens have enjoyed effectively free water, electricity and gas from the early days of independence from the Soviet Union. Now there will be no more freebies for citizens of the country with the world's fourth biggest gas reserves, behind only Qatar in reserves per capita.\nThe reason? An energy price-linked financial crisis, which has also seen the local manat currency sharply depreciate, the cost of imported foods and other goods spike and shortages pop up all over the economy.\nAs <PERSON> a PR-Director at neighbouring Kazakhstan's Kazakhfilm company, wrote:\nКажется, Туркменистан почти всё. Добрались костлявые руки углеводородного кризиса до родины башизма. Ждём появления центральноазиатской Венесуэлы.\nThis is the end for Turkmenistan. The crisis has reached the country. Now we’ll see the appearance of the Central Asian Venezuela.\nPetro-dollars dry up\nSome of the parallels thrown up by <PERSON>'s comment are interesting to ponder.\nLike Venezuela, Turkmenistan's economy is very undiversified, with hydrocarbons accounting for over 90% of both countries’ exports.", "148" ], [ "Like Venezuelan President <PERSON>, Turkmen President <PERSON> came to power following the death of a more charismatic predecessor. Finally, both <PERSON> and <PERSON> have found their governments increasingly unable to meet the basic needs of their populations and pay wages on time as energy profits have shrunk.\nYet in other ways, the two countries are very different. While Venezuela has slid deeper and deeper into authoritarianism amid a profound economic, social and political crisis, Turkmenistan has long been a totalitarian state with rubber stamp political institutions and courts unworthy of the name. In Reporters Without Borders press freedom rankings Venezuela places 137th out of 180 countries, while Turkmenistan places 178th. The Central Asian country's internet is among the most restricted in the world.\nWith political opposition, independent sources of information and the civic space almost completely invisible in Turkmenistan, it seems unlikely that the <PERSON> regime can be troubled by the sort of protests that have dogged the <PERSON> regime and seen it resort to brutal violence against protesters. The democratic institutions that <PERSON> has aggressively sought to erode in Venezuela, by dissolving and then weakening the national assembly dominated by opposition, and by stuffing the judiciary with loyalists, have simply never existed in Turkmenistan.\nBut that does not mean that the Turkmen regime does not have dark days ahead of it, as a nadir mostly of its own making continues to deepen.\nBig spenders on unnecessary things\nSharing responsibility for the country's economic malaise along with low oil and gas prices and systemic corruption is the Turkmen government's propensity to spend wastefully on vanity projects. A new falcon-shaped airport in Ashgabat set the government back more than $2 billion and is reportedly sinking into the ground. The Central Asian state is also spending billions of dollars on hosting a B-list sporting tournament, the 2017 Asian Indoor and Martial Arts Games, that it committed to before the oil price crisis began, with whole communities reportedly being forcibly displaced for the purpose of building infrastructure ahead of the games.\nThese projects — rather than state subsidies — are apparently the new priorities for a government that claims citizens are living in the era of “supreme happiness and the stable state.”\nWriting on Facebook, Azerbaijani <PERSON> suggested that the extent of the economic downturn in the country means they will soon be living somewhere else entirely, joining millions of citizens from other Central Asian states earning a living abroad in order to feed their families.", "704" ], [ "Post-election protests spark another revolution in Kyrgyzstan · Global Voices\nMass protests on Ala-Too Square, Bishkek, Kyrgyzstan, October 5, 2020. Photo (c): <PERSON>. Used with permission.\nMass protests against electoral fraud in Kyrgyzstan have overthrown the country's government.\nOn October 4, this Central Asian country of 6.3 million voted in parliamentary elections. Kyrgyzstan is known for its fractious politics; some 16 parties competed for 120 seats in the country's unicameral parliament. But opposition voters were in for a disappointment. The Central Electoral Commission's (CEC) preliminary results counted 1,942,609 votes and indicated that just four of these 16 parties had passed the threshold of seven percent: Unity (24.9 percent), My Homeland Kyrgyzstan (24.27 percent), Kyrgyzstan (8.89 percent), and United Kyrgyzstan (7.19 percent). The final turnout was 1,980,240 people, or 56.2 percent of those included in voter lists. A manual vote count conducted on October 5 showed much the same results, although a fifth party, Mekenchil, also entered parliament with 7.26 percent of the vote.\nAll the remaining parties still got less than seven percent of the vote.\nThe parties which managed to clear the threshold were all pro-government parties linked to powerful figures in Kyrgyzstan's ruling political elite. For example, Unity is associated with President <PERSON> and his brother is among its candidates. My Homeland Kyrgyzstan is linked to former Deputy Head of Kyrgyzstan's customs service <PERSON>, who is at the centre of an international investigation into the withdrawal of almost US$700 million from the country.\nThese elections also marked the tenth anniversary of Kyrgyzstan's transition to a semi-parliamentary republic. <PERSON>, an Associate Professor at the International College of Security Affairs in Washington DC, noted that despite this change, the most influential political parties tended to dominate elections. They were strongly associated with their patrons, internally divided, and had no substantial ideological distinctions, she explained:\nBy then it was also apparent that a representative parliament =/= more democratic legislature. Lots of laws limiting civic and economic freedoms were passed\n<PERSON> and then <PERSON> were seizing more political control, often capitalizing on parties’ lack of internal cohesion\n— <PERSON> (@Ericamarat) October 5, 2020\nOpposition supporters felt cheated. The Social Democrats were the first opposition party to announced that they refused to recognise the result of the election, announcing a protest on the night of October 4.", "148" ], [ "The Republika and Ata-Meken parties then held a joint briefing and asked their supporters to join the demonstrations.\nAccusations of electoral fraud were raised widely across social media. Many of these were connected with so-called Form No. 2 votes, which the head of the CEC <PERSON> described as “a progressive norm which allows the voter to vote not at their place of registration, but wherever is convenient for them”. <PERSON> stressed that 481,950 such applications were registered ahead of the October 4 vote. Lawyers sounded the alarm at this large number and appealed to the CEC, Prosecutor Generals's office and law enforcement agencies to investigate the matter. “Every case of mass registration of citizens in Form No. 2 and every report of voter bribery should be the subject of a thorough, objective, and prompt investigation,” the lawyers stated in an open letter.\nReports that political parties were bringing voters from regions or villages and registering them at polling stations in Bishkek had started to appear online as far back as early August. One voter told journalists of 24.kg that he was promised 4,000 Soms (US$50) to vote for My Homeland Kyrgyzstan. He continued that he was told to submit an application via Form No. 2 in order to change his electoral address, then handed a completed form and brought by minibus to a polling station located in a school.\nOn election day, social networks were full of complaints by voters about bribery by Unity and My Homeland Kyrgyzstan. Voters claimed that they were offered between 1,500 and 5,000 Soms ($19-63) for voting “correctly”.\nFor many voters, electoral fraud may have been the last straw. In recent years, the country has been rocked by incessant corruption scandals and political instability. People's discontent grew and accumulated. Against the backdrop of the COVID-19 pandemic in Kyrgyzstan, which peaked in July this year, President <PERSON>'s popularity declined sharply, although even before the pandemic, his actions and team were often criticised.", "609" ], [ "Is Tajikistan’s President ‘Preparing Himself a Parachute’ with Constitutional Changes? · Global Voices\n<PERSON> and family. Wikipedia image.\nOn May 22 Tajikistan will hold a referendum on the <PERSON> family that has ruled it for over two decades against a backdrop of economic dysfunction, pervasive corruption and political repression.\nOn the day at least, the family is almost certain to get its way.\nTajikistan is the poorest of the 15 countries to emerge from the ruins of the Soviet Union in 1991.\nAs soon as the country gained independence, it fell into a five-year civil war that saw <PERSON> and his allies emerge as the country's decisive political force.\nLeader of the Nation\n<PERSON>, 63, is sometimes likened by citizens in the country to the shah of Iran overthrown in the 1979 Iranian Revolution, due to his intolerance of the religion of Islam followed by over 90% of the country's citizens.\nAmendments to the constitution that will be voted on in May include a ban on political parties created on religious grounds, as well as a stipulation that will allow ‘The Founder of Peace and National Unity, Leader of the Nation’ to stand for president an infinite number of times.\n<PERSON>'s Leader of the Nation title was awarded him by parliament in December.\nIn speech to the deputies the speaker of the lower chamber MP <PERSON> said:\n“Этот закон не нужен президенту Эмомали Рахмону, он нужен нам, народу, чтобы закрепить взятый им курс, нацеленный на мир и процветание. Принятый документ – это дань уважения трудам и заслугам великого сына страны. Эмомали Рахмон – спаситель нации, объединивший таджикский народ после тысячелетнего разобщения. Он спас и возродил таджикскую нацию.", "148" ], [ "История услышала боль народа и подарила ему смелого, заботливого, честного, любящего и миролюбивого руководителя, лидера”\nPresident <PERSON> does not need this law, we, the people need it, in order to strengthen the course he has taken, which aims at peace and prosperity. The adopted document is a tribute to the works and merits of this great son of the country. <PERSON>, the saviour of the nation, united the Tajik people after a thousand years of separation. He has saved and revived the Tajik nation. History heard the nation's pain and gave it a brave, caring, honest, loving and peace-loving leader.\nOn a practical level the Leader of the Nation status allows <PERSON> and his family immunity from criminal prosecution, and the inviolability of their properties among other things, even after he leaves office.\nAs one commenter on the Tajik service of RFE/RL commented:\nГотовит себе парашют.\nHe is preparing himself a parachute.", "148" ], [ "The Rest of the World Is Finally Noticing the Touristic Charms of Central Asia · Global Voices\nIrkht, Badakhshan, Tajikistan. Photo by <PERSON>. Used with permission\nThe glorious natural beauty of Central Asia is breathing some fresh air into the region's international reputation, so often sullied by the authoritarian rulers who hold power there.\nTajikistan ranked second on the list of fastest growing tourist destinations that the United Nations World Travel Organisation released recently, registering a whopping 94% increase in visitors during 2015.\nAnd a couple of weeks ago, Kyrgyzstan made it into UK newspaper the Financial Times‘ list of top seven travel destinations for 2016 according to industry insiders.\nThat the former Soviet Stans are attracting the attention of the world's media as undiscovered, exotic, virgin tourist destinations is a nice change for Central Asia, which more often than not appears in international media for instances of violence, military clashes, human rights abuse, economic collapses, and absurd laws.\nLast year, Global Voices profiled the stunning nature of Tajikistan in pictures and offered potential visitors a guide of the main spots to check out.", "148" ], [ "Now let's return to the topic and take a look at the magnificence of five Central Asian Stans, with the help of drone footage and promotional videos.\nKazakhstan\nThe ninth largest country in the world by area, Kazakhstan has much to offer, from its traditional nomadic culture and newly built capital Astana to its steppes, taiga and rock canyons.\nKyrgyzstan\nThe Financial Times has a few suggestions for its readers who visit Kyrgyzstan:\nHiking in the Tian Shan mountains, riding over the grass-covered steppes or mountain biking on ancient Silk Road routes, and staying in traditional yurts surrounded by wilderness.\nTajikistan\nFor nature lovers, the land of Tajikistan is 93% mountainous with ethereal alpine lakes dotted all over. For history buffs, the country's past is full of battles against invaders, starting from <PERSON> to <PERSON>. And for the spiritual, you can find the largest <PERSON> statue in nirvana, visit the ancient Zoroastrian temple, and speak the mother tongue of <PERSON>.\nTurkmenistan\nInternationally famous Akhal-Teke horses, first-class handmade carpets, desert and camels, cities peppered with golden statues – all that is in Turkmenistan, the country that possesses the world’s fourth largest natural gas reserves.\nUzbekistan\nBe charmed by the ancient cities of Bukhara and Samarqand, relive the history of past empires on the Silk Road stops, and meet both Turkic and Persian civilizations in Uzbekistan, often called the pearl of Asia.", "849" ], [ "When Is an Autonomous Territory Not Autonomous? When Tajik State Media Says so? · Global Voices\nGorno-Badakhshan Autonomous Oblast (GBAO) marked in red. Tajikistan borders Afghanistan to the South, China to the East, Kyrgyzstan to the North and Uzbekistan to the West. Wikipedia image.\nIn recent months, ex-Soviet Tajikistan's state media has stopped calling the Gorno-Badakhshan Autonomous Region (GBAO) autonomous, a trend that has caused irritation among the fiercely independent minority population that inhabits the restive territory.\nGBAO — defined topographically by the soaring Pamir mountain range and culturally by the Pamiri Ismailis that make up most of its 200,000 plus population — was first formed according to a decree of the Soviet Union's Central Executive Committee on January 2, 1925.\nThe territory retained its autonomy throughout the Soviet Union and into the Central Asian state's independence, even after a ruinous five-year civil war that saw many of the region's people fight against the government in the ranks of the failed United Tajik Opposition (UTO).\nRecent years have showed an increasing intolerance for the region's otherness on the part of the central government in Dushanbe, however.\nAutonomy goes missing in TV weather forecasts\nIn the independence period, tensions between the region and the regime peaked in 2012, when a high-ranking security official close to the regime was assassinated by other government officers with pasts linked to the dissolved UTO.\nThe Tajik government's response was a disproportionate if clumsily executed show of force.\nWhile people still dispute who “won” the standoff between government troops and local residents that claimed several dozen lives, it is certain the government control over the region is shaky at best.\nOn February 19, <PERSON>, a poet and deputy chairman of the Writers’ Union of Tajikistan addressed a letter on Facebook to <PERSON>, Chairman of the State Committee for Television and Radio protesting state media's references to GBAO simply as ‘Badakhshsan province’.\nHe argued the apparent policy “can lead to misunderstandings between Badakhshsanis, becoming a reason for the rise of artificial contradictions.”\n“Neither the Chairman of the Radio and Television, nor anyone else has the right to ignore the Constitution of Tajikistan, in which the region is officially listed as ‘Gorno-Badakhshan Autonomous Region’,” <PERSON> told RFE/RL's Tajik service, complaining weather forecasters and newsreaders in particular were systematically referring to the territory without its ‘autonomous’ designation.\nReferendum fears dispelled…for now\nOn social networks GBAO locals reacted emotionally to the new tendency, with many fearing that the territory's status could could be threatened in a forthcoming constitutional referendum.\nBadakhshan native <PERSON> launched a flash mob on Facebook, in which he called for a continuation of Badakhshan's autonomy.\nДрузья бытует мнение , что в марте этого года планируется проведение референдума , в честь аннулирование статуса автономии БАДАХШАНА .", "148" ], [ "Why we must keep shining a light on Turkmenistan · Global Voices\nA news presenter on Turkmenistan’s Altyn Asyr TV channel, reporting on the latest feats of president <PERSON>. Turkmenistan has one of the world’s worst records on media freedom. From <PERSON> YouTube video on 28 August 2019.\nMy country is one of the most repressive dictatorships in the world.\nTurkmenistan, an arid country in Central Asia, is ruled by a narcissistic president known for bizarre publicity stunts and vanity projects, alongside a truly appalling human rights record. He presides over a state that, despite having a wealth of natural resources, is in deep economic crisis. The situation for ordinary Turkmens is dire, with rising unemployment and food shortages. As the queues outside stores grow, fights break out over bread.\nUnsurprisingly, the authorities are not eager to publicise these hardships. The country was recently ranked at the very bottom of Reporters Without Borders’ 2019 World Press Freedom Index, “beating” North Korea and Syria. Independent media is non-existent and communication between citizens is severely restricted, so if news travels at all, it travels covertly. That’s where I come in.\nI am the founder and editor of Turkmen.News, a Netherlands-based news site launched in 2010 under the name Alternative Turkmenistan News. We publish news and analysis on the country’s economic, social, and political environment. My work has taught me that the task of getting objective information out of Turkmenistan is as difficult as it is crucial.\nThis past July, I participated in an event in London hosted by the Foreign Policy Centre, a UK think tank. In collaboration with academics, researchers and politicians, we launched a report that aims to bring international attention to the situation in my country. Entitled Spotlight on Turkmenistan, the report shines a light on one of the world’s most autocratic and corrupt regimes.\nState institutions in Turkmenistan are both corrupt and dysfunctional. I recently reported on Turkmen prisons, where disease is rife, and the guards have developed their own sophisticated systems of extortion to allow prisoners access to basic necessities. The country practises medieval torture methods, enforced disappearances and annually showcases one of the world’s most egregious examples of forced labour during the annual cotton harvest.\nThe report highlighted an internal business environment rotten to its core.", "926" ], [ "My recent exposé of a $2.3bn infrastructure contract handed to the president’s brother-in-law is just one example of the networks of profit which exist solely to ensure the stability of the regime. The panel in London noted that foreign investments in recent years have been derailed through the unpredictable repudiation of contracts and licences; several clients, including Russian telecom operator MTS and Belarusian construction company Belgorkhimprom, are now lining up to sue Turkmenistan’s government.\nOrdinary citizens in Turkmenistan have no access to such news, either from domestic or foreign sources. All foreign media is banned. This relates not only to western outlets such as Reuters, the BBC and Deutsche Welle, but also Russian language websites (both pro-Kremlin and oppositional) including Meduza, TASS and Ekho Moskvy. Although several different Turkmen papers exist, their reports are formulaic, and all glorify President <PERSON>.\nThe inability to share news or express discontent is compounded by an almost total ban on social media: Instagram, YouTube, Facebook, and the Russian social networks Odnoklassniki and Vkontakte, among other, are all forbidden. As the situation In Turkmenistan deteriorates, the state tightens its hold over any independent voices.\nBut even in such darkness, there is a flicker of hope. Projects dedicated to reporting the daily sufferings of the Turkmen people are being created outside the regime’s reach, such as the Vienna-based Chronicles of Turkmenistan. Sites such as these are the only form of reliable information about the country. My site Turkmen.News works with a network of brave Turkmens who smuggle news out of the country through encrypted messaging systems. They do so at considerable risk to themselves and their families. Several journalists in Turkmenistan have already been arrested or, like me, forced to flee the country.\n<PERSON> was one of our reporters, monitoring the use of forced labour during the cotton harvest. In 2016, he was arrested on trumped-up charges of fraud and bribery and sentenced to three years in prison. On September 6, 2019 he was finally freed after having served his prison term in full. Another of our journalists, <PERSON>, was sentenced to three years in prison in 2015 for allegedly possessing illegal substances. Both <PERSON> and <PERSON> have received support from the international human rights community and a UN working group.", "704" ], [ "Uzbekistan releases its “last detained journalists” · Global Voices\n<PERSON>, Uzbek journalist. Photo by Radio Ozodlik\nOnce known as one of the world’s most despotic regimes, Uzbekistan continues to move closer to a free society since new president <PERSON> came to power in September 2016.\nOn May 7, 2018, the former Soviet Central Asian republic freed two journalists, <PERSON> and <PERSON>, who were detained in September and October 2017 for “anti-constitutional activities”.\nThe Committee to Protect Journalists welcomed this move by the Uzbek authorities and declared that for the first time in last two decades there are no journalists left behind bars in Uzbekistan. Other international organizations also expressed their approval of the move. The international community had been keeping a special eye on this case, as it was the first time since the arrival of Uzbekistan's new president that journalists had been detained in the country.\nThe OSCE Representative on Freedom of the Media, <PERSON>, welcomed their release and urged that “all remaining charges should be dropped.”\nSince the collapse of the Soviet Union, Uzbekistan had been ruled by the iron-handed <PERSON>, until he died in September 2016. <PERSON>’s long-serving Prime Minister <PERSON> replaced his late boss, launched some economic and political reforms at home, and catalyzed changes in regional integration.", "148" ], [ "Among the political changes was the release of several political prisoners who had served decades in prison. According to the Committee to Protect Journalists, five journalists, not including the two released this week, were also freed in the past one and a half years.\nIt was during this period of political reform that journalists <PERSON> and <PERSON> were detained on the same charges <PERSON> regime had used to imprison political opponents and journalists for years. The outcome of this case would show whether President <PERSON> was committed to continuing his reforms and an open-door policy or just temporarily playing the role of “good cop” to win people’s support for his internal political battles.\nThe detained journalists were charged with writing articles calling for the violent overthrow of the regime in Uzbekistan under a pseudonym. The journalists recognized that their articles had raised problems, but denied that this included calls to violence.\nWhen security forces officers in charge with investigating the case became themselves embroiled in a power struggle between the powerful former head of Uzbekistan’s security forces, <PERSON>, and the new president <PERSON>, many hoped that the journalists <PERSON> and <PERSON> would be freed.\nOn May 7, the court acquitted <PERSON> of all charges, but found <PERSON> guilty of “extremism”, sentencing the journalist to three years of community service. The judge released both directly from the courtroom.\nMinutes after breathing in the air of freedom and hugging his family members, <PERSON> gave an interview to his local colleagues, saying:\nThe fact that I am free now, and the fact that the court hearing was open, are fruits of the liberal politics of the President <PERSON>.\nUzbekistan, like many other former Soviet republics, is a country where even small political moves are subject to the ruler’s approval.\nAs CPJ Europe and Central Asia Program Coordinator <PERSON> commented:\nNow that the country has freed its press from physical custody, authorities must build on this progress to ensure that the media are able to do their job independently and without fear of reprisal.", "409" ] ]

[ 6314, 9375, 2492, 7230, 7273, 4666, 7474, 10871, 6296, 1840, 10984, 3028, 8610, 4037, 9170, 3932, 9052, 3776, 10550, 2388, 414, 6623, 461, 11308, 2480, 2805, 7837, 5842, 11428, 5789, 1860, 3067, 8017, 11281, 6388, 4247, 6009, 4777, 9433, 7275, 1565, 5439, 2226, 7524, 5931, 1856, 314, 2699, 3294, 2081, 10795, 3600, 6421, 10495, 6364, 11309, 7404, 2961, 10596, 11370, 268, 5946, 5678, 7209, 8412, 2996, 9836, 4921, 1371, 6299 ]

[ [ "Event Countdown Clock (Covid Clock - V2.0)\nIntroduction: Event Countdown Clock (Covid Clock - V2.0)\nThis is an upgrade to my earlier version of this project. I debated with myself whether I should just update the old project or post this new one. Obviously I eventually decided to post this as an \"Upgrade\". I decided this because while working on this project (which I built from scratch), I felt that the wiring was sufficiently complicated and tedious that the original project was a good stepping stone to get working, then it could fairly easily be modified to create this enhanced version.\nHowever, if you wish to tackle this project from scratch, the complete wiring diagram (and a schematic) are included in Step 2. Feel free to jump right in and hook it up as you wish.\nThe original project can be seen here. This instructable is presented as an \"add-on\" to the original Coronavirus Quarantine Clock. The code in this instructable won't work as is with the V1 project. The main reason for this is that the signalling used to manage the 7 segment LED display has been inverted due to the inclusion of the transistors.\nSo, what is new?\n* The LED display is dimmable (see note below).\n* The code has been modularised.\n* There are additional commands.\n* The target date is stored in EEPROM so that it will be retained across restarts.\nRegarding the dimmable display. There are loads of projects online that allow LEDs to be dimmed.", "288" ], [ "So what is so special about this?\nThe LED dimming is special because it uses a \"home grown\" digital potentiometer. Most LED dimming projects online use PWM to dim LEDs, so why not do that? PWM works fine for dimming the LED bar graph, but since the clock display is updated / managed with strobing (due to the shared pins on the panel), applying PWM to the clock display resulted in a rather wierd looking \"rolling\" or \"scrolling\" effect. This effect would vary depending on the PWM rate.\nThe other interesting thing about the LED dimming is that it shows an alternative way to achieve dimming of LEDs for those situations when PWM is not desirable.\nSupplies\nIn addition to the parts in the original Coronavirus Countdown Clock, you will need the following:\n* (Optional) another breadboard. I found that I couldn't easily fit all of the components on one medium sized (830 pin) breadboard.\n* 8 x NPN transistors (I used BC337, but any similar NPN transistor will be OK).\n* 8 x 10 K resistors.\n* 4 x 50 ohm resistors (I used 100 ohm, but feel that these were too \"strong\" and 100 ohm was the smallest that I had).\n* 1 x LDR with about 48-140K range (but anything close is OK).\n* 1 x 2K2 resistor for use with the LDR (again, anything close is OK, but you probably don't want to go any smaller than 2K2).\nStep 1: Wiring Preparations From V1 Project\nAs shown in the breadboard diagram, there are only two modifications to the V1 project to prepare your circuit for the additions for V2.\nThese are:\n1. Remove red and black wires bridging the top +V and GND bus to the lower bus on your breadboard.\nThe lower bus will be used to collect the cathodes of the various LEDs and feed them into the brightness controller\n2. Seperate the 4 wires that select the digits into the LED panel into two parts. These are the four wires with the white bands in them.\nWe still need both sides, but we will insert 4 of the transistors between the Arduino end and the LED panel end.\nStep 2: Add the V2 Connections\nThe diagrams above show the complete circuit for this project.\nNote that in the diagram there are 3 seperate \"power\" lines. These are:\n* GND - which uses black wires and connects to one of the Arduino GND pins\n* +5V - which uses red wires and connects to the Arduino's +5V pin.\n* GNDA - which uses solid blue wires and connects the cathodes of the LEDs to the brightness control circuit. This wire does not connect directly to the black GND wire (nor the red +5 V wire).\nLED Digit Control\nThis sub-step connects up the transistors for the digit selection on the 7 segment LED display panel.\n* Find some space on your breaboard and insert four of the transistors.\n* Connect one 10 K resistor (four in total) to each of the transistors' base pins.\nThe base pin is the middle one.", "611" ], [ "Kissing the Frog V2.0 - Back Horn Bluetooth Speaker Fully Printable\nIntroduction: Kissing the Frog V2.0 - Back Horn Bluetooth Speaker Fully Printable\nIntroduction\nLet me start with a little background. So what is a back loaded horn speaker? Think of it as a reversed megaphone or gramophone. A megaphone (basically a front horn loudspeaker) uses an acoustic horn to increase the overall efficiency of the driving element (i.e. the sound coming out at the front). A back loaded horn speaker does pretty much the same thing. However, here the horn is mounted to the back of the speaker. So you get the direct output from the front of the driver PLUS the one from the horn at the back. Which frequencies are amplified and how well depends on the air chamber, throat (the narrow part), and on the length, design, and diameter of the horn. Particularly with small (and cheap) drivers this can very much improve the sound quality.\nI would call this concept \"Kissing the frog\". You take that little tweeter and hope it turns into a prince. And yes, it actually does. It is amazing how much sound you can get out of a $10 3.3\" driver.\nYou will find loads of books, papers, and online references for how to design an optimal horn speaker. The problem is that your calculated optimal horn will likely end up taking up most of your living room. However, I found these tools incredibly helpful to better understand the dynamics (i.e. what happens when I change the diameter, length, design of the horn?). Ultimately, the design of a (back) horn speaker (definitely a 3D printed one) will largely be guided by the available space while trying to get as much sound out of a relatively small enclosure / driver.\nFor this design you will need to have access to a 3D printer. I am using a $ 200 Creality Ender 3 3D printer, which can do prints up to 220x220x250 mm (and does a great job at that). The body is designed to fit a standard 200x200 mm build plate, so most (even budget) printers should be capable of printing this.", "729" ], [ "If you want to use it as a Bluetooth speaker you will need basic electronic and soldering skills. Make sure that you know what you are doing (particularly dealing with high voltage! So take care, all at your own risk and no warranty whatsoever). However, remember, you can always use the enclosure as a passive speaker, which omits all the soldering.\nStep 1: Electronic Supplies\nBasically this is a super cheap project. All electronic supplies you need for the Bluetooth version should cost around $20.\n- First of all you will need an MP3 Bluetooth Decoder Board (approx. $ 1) (the same on Amazon). You could in theory use an amplifier with integrated BT board. The problem is that this way you will inevitably end up with a stereo speaker signal - good if you want to connect 2 speakers (the 2nd speaker being connected to the first by wire), bad if you want a single (mono) speaker as you cannot pool output signals from both amplifier channels. The separate BT board allows for pooling the line out signal before feeding it into the amplifier.\n- The amplifier is a TPA3116 D2 Dual Channel 50Wx2 Amplifier Module (approx. $ 3.5) (the same on Amazon)- this one is stereo (which seems like a waste, however, stereo amplifiers are nowadays easier to find than mono and considering the cost of 3.5 $... and may come handy in case you want to connect 2 speakers). For mono you will need to bridge L and R channels coming from the BT board (see the wiring section).\n- Pretty much any 12V/1A+ (the more the better) power supply (approx. $ 1.7) (the same once again on Amazon) will do. E.g. an old 12V laptop power adapter would be great. I use a small 10x15 mm rocker switch as power switch (which is optional as the amplifier has a switch built into the volume control - which, however only switches the amplifier).\n- A small LM1117 Step Down converter (approx. $ 0.2) (the same on Amazon). This will convert the 12V from the power adapter to 5V needed for the BT board.\n- The driver I use is a Visaton FRS 8 M - 8 Ohm 8 cm (3.3\") full-range speaker (around $ 10). The exact same driver may be difficult to find in the US but here a few options on Amazon.\nHowever, basically any combination will do (as long as the driver is 3.3\" or smaller so it fits the enclosure - if you use a different driver you may have to slightly adapt the mounting holes).", "485" ], [ "How to Make a Driftwood Mood Lamp With Infrared Remote Control (using Arduino, an ATtiny85 and an Adafruit NeoPixel Ring)\nIntroduction: How to Make a Driftwood Mood Lamp With Infrared Remote Control (using Arduino, an ATtiny85 and an Adafruit NeoPixel Ring)\nI wanted to make a lamp from some old aquarium driftwood that was lying around, where the colours could be selected using an infrared remote and that would run on USB power using the small powerful ATTiny85 chip.\nThe design allows the user to choose from warm colours (reds, purples, oranges), cool colours (greens and blues) or specific colour choices. A total of 9 different selections. It also has adjustable brightness settings.\nSupplies\nEquipment needed as follows:\nFor base:\n* Old pieces of wooden patio decking\n* Gnarled driftwood\n* Wood glue\nFor electric circuitry:\n* An Arduino\n* Breadboard\n* Adafruit Pixelring (12 LED variant)\n* Infrared remote and receiver\n* Capacitor 100-1000 uF and atleast 6.3v\n* Resistors (470 ohm) and (4.7k ohm)\n* ATtiny85\n* Sparkfun ATtiny Programmer\n* Micro USB power source\n* L-Headers\n* USB extension cable (here)\n* Button switch\n* Wire in different colours\n* Heat shrink wrap\n* (Note I have created a PCB that makes the project neater. I have shown this at the end.)\nTools needed:\n* Small router for base edging\n* Table saw\n* Soldering iron and solder\n* Dremel tool\nStep 1: Make the Base\nThe base is made from two pieces of old patio decking we had lying around.\nStart by cutting off the edges using a table saw, leaving the width of both main pieces of wood at 8cm each (meaning removing 1.5cm from each side). This should leave you with two pieces of wood 16cm by 8cm. Obviously adjust this as needed based on the width of wood available.\nThen glue those two pieces together to form a 16cm x 16cm base.\nNext glue the offcuts to the base (per the picture) having cut the corners to 45 degrees.\nThis will allow enough depth to fit all the electronics into, later in the project.\nFinally shape the edges with a router to give an elegant finish on the upper side.\nStep 2: Add the Pixel Ring, Infrared Receiver and USB Power Source\nNext, drill three small holes to allow the legs of the infrared receiver to connect from the surface to the underside of the project.\nAlso cut three more holes in the correct position for the pixel ring (the points you need to connect are 5V, GND and data in).", "769" ], [ "Ignore data out for this project.\nSolder wires to the three legs of the IR receiver and also the pixel ring.\nFinally cut a hole using a Dremel to allow a micro USB extension to be fitted (the one I used is shown in the image and goes from female (with a flush fitting) to male).\nStep 3: Test the Circuit on a Breadboard Using an Arduino\nI used an arduino micro for testing but use any you have to hand.\nThe wiring is as follows:\n* IR receiver signal wire to Pin 5 of micro arduino\n* Connect Pin 9 of Arduino to Pixel ring data in wire via a 470 ohm resistor (suggested in best practice guide from Adafruit. See here for details.)\n* All other lines connected to 5v and GND with a 100-1000 uF (atleast 6.3v) capacitor between the lines. I used a 1000uF 16v variant.\nNext ensure that you know the correct codes from the Infrared transmitter so that you can code the buttons to do what you want them to do.\nTo do this follow the instructions shown here. Note the need for the IRremote.h library to be added in the Arduino IDE. The result will be that you will have an accurate list of codes for each button on your remote.\nThen use the following code ensuring that you change the RGB colours to the ones you want and amending the \"Define Key\" section to be correct for your IR remote.\nAlso note that both the IRremote.h and Adafruit_NeoPixel.h libraries are needed for this code. You can add these in the Arduino IDE Manage Library tool.\nThe code does something quite simple:\n* Buttons 1-5 just show single colours.\n* Button 6 to 8 cycle though colour combinations.\n* And button 9 runs the lovely Rainbowcycle sequence.\n* Button 0 then turns the LEDs to Black.\n* Finally the right and left keys increase or decrease the brightness.", "991" ], [ "Daily Running Tracker\nIntroduction: Daily Running Tracker\nHi All,\nIt's been a while since I made an instructable so I'd like to share something fun that I made recently. During lockdown I made my own yearly \"everyday calendar\" inspired by <PERSON> own idea (no instructable but photo attached for those interested). My better half wanted something similar to track her running (but on a 7 day weekly basis rather than a year). It also had to keep track of how many miles she ran not just a single light indicating a task had been done or not. Additionally, I wanted it to sing and dance and do lots of shiny LED business when she exceeded her target. The idea for the daily running tracker was born, so in summary it must:\n* Log miles ran every day of the week\n* Compare 'miles ran' against a set goal for that day\n* Reward the user with a celebratory song and some flashy lights\n* Be small enough to fit on a desk\n* Remember everything when the power was turned off (comit everything to non-volatile memory)\nSupplies\nFor this project I used:\n1. A 3D printer (for the enclosure designed in FreeCAD)\n2. M3 screws, and brass M3 inserts\n3. A soldering iron\n4. Jumper wires or wires of some kind\n5. x9 momentary push buttons\n6. x7 WS2812 addressable LED's\n7. x7 SSD1306 OLED 128x32 pixel Displays\n8. A 4 Ohm speaker\n9. The DY-SV8F playback module\n10. An Arduino Mega\n11. DC barrel input\n12. The TCA9548A multiplexer\n13.", "769" ], [ "13. Arduino Mega prototyping board\nStep 1: Operation\nPush buttons\nThe user does a short push to enter the distance ran (Distance input mode) for the particular button pressed for the day in question (the DAY button), then uses an UP and DOWN button to increment the miles in 0.01 increments. A long push for more than 3 seconds will allow the user to enter the target/goal (target input mode) for that particular day, and UP and DOWN is used again to set the goal in 0.01 mile increments. A short push of the DAY button will confirm the entry of either the goal or target depending on which mode the unit is place in.\nA long press of the push button allows the targets to be reset by clearing the EEPROM memory. When pushed for more than 3 seconds the displays will ask if the user if they are sure and display UP = YES, and DOWN = NO, to confirm their entry. A short press on the UP button will write a bunch of 0's to the EEPROM and the display will show \"ALL MEMORY ERASED\". I think an encoder would of been a nicer idea but I wanted to use up some push buttons I had in stock.\nLED's\nBy default the LED for each day is red until the distance ran for that day exceeds the target set, in which case it turns to green. When the user enters distance input mode the LED turns light blue to indicate the unit is waiting for the user to input the miles, and deep blue when target input mode is selected. For confirmation of a target/distance when the user pushes the DAY button again to exit the input goal/target mode the LED with perform a colour cascade as an acknowledgement it has received the command. Finally when the user reaches the goal it will flash wildy different colours.\nDisplays\nMy original idea was to use the I2C bus to string multiple OLED's together, however I found out that the SSD1306 OLED's are typically hard coded with the same I2C address. That is why I had to use the TCA9548A multiplexer to allow separate addressing of individual displays. This displays a little running man and some chevrons to indicate the user is in distance input mode, and a crosshair with chevrons to indicate target input mode. I used the purple one picture above. I have included a fritzing diagram above which illustrates an example of how to connect 4 of these sorts of OLED's to an Arduino UNO, although it is the same for 7 OLED's and the MEGA.\nSound playback\nI wanted a module which would handle all the play back of music segments. I wanted it to be simple to use/implement and play at decent quality and volume. The DY-SV8F module pictured above seemed an obvious choice. It plays up to 255 MP3 or WAV files, 10 files which are directly triggered by a logic LOW signal at one of it's input pins. A microSD card was loaded with 7 music MP3 files each about 20 seconds long (cut down and faded in/out using Audacity).", "769" ], [ "Audio Delay for Auditorium Speakers\nIntroduction: Audio Delay for Auditorium Speakers\nMany auditoriums/churches have speaker arrays with speakers at different distances from the stage to reinforce audio throughout the venue. However, the sound reaching a listener from these speakers will come at different times and this can cause a reduction in intelligibility. (Sound travels approximately one foot per millisecond.) The right solution is to delay the sound from speakers further than the stage so that sound reaches a listener at the same time from the multiple speakers.\nA neighbourhood church had three sets of speakers in their sanctuary, the main speakers, and two sets of speakers further back (26 feet and 37 feet respectively). Their audio delay hardware was broken and I volunteered to build a replacement (primarily to learn more about audio electronics and microcontrollers, I normally write software).\nA quick investigation revealed that PJRC had an Audio Adaptor board for their Teensy microcontrollers that I thought would be appropriate. Furthermore, their Teensy Audio Library would make it easy to develop the software that would be needed.\nSupplies\n* Teensy 4.0 microcontroller\n* Audio Adaptor board\n* 0.91\" I2C 128x32 OLED module\n* rotary encoder with built-in switch x2\n* female XLR panel mount connector\n* male XLR panel mount connector x2\n* M3-10mm screws to mount the XLR connectors x12\n* 1/2 sized PCB breadboard\n* female headers (14 pin) x2\n* header pins\n* jumper wires\n* metal case (10 cm x 5 cm x 10 cm, 4\" x 2\" x 4\")\n* micro USB cable, 3 feet\nStep 1: Prototype\nThe prototype was relatively simple to build. Unsure of my soldering abilities I soldered female headers on the Teensy board (I couldn't find 14-pin headers so the ones I purchased extended beyond the Teensy PCB) and pins on the audio adaptor board. This would allow me to replace one or the other board if my soldering was really bad. (I shouldn't have worried; it was easier than I thought.)\nThe female headers had extra long pins that allowed me to insert them into the breadboard. I used jumper wires to connect to the rotary encoders on another breadboard. (The encoders themselves didn't sit well in the breadboard resulting in issues when I tried to debug the software.)\nI connected a signal generator to the input pins on the audio adaptor board and an oscilloscope probe to the output pins to test the prototype. I measured a latency of about 6 ms.\nStep 2: Software\nPJRC, which makes the Teensy and the Audio Adaptor board, has a software add-on for the standard Arduino development platform.", "1003" ], [ "For the Mac (which I used to develop this project), it is a single download that combines the PJRC's software along with the Arduino development software.\nThe combined download should have included the PJRC's Audio library but I didn't see it so I downloaded it directly from Github.\nI also needed a driver for the OLED display so I used Adafruit's 1306 and GFX libraries.\nWriting the software to produce audio delay was surprisingly easy. PJRC has a graphical Audio System Design Tool that runs in the browser (see image). The various components are on the left-hand side of the web page. When you select a component the right hand side of the page tells you more about it. You drag and drop components into the middle section and draw wires from the inputs and outputs of these components to configure the audio software. Once you are happy with your design you export the design and it creates Arduino code that talks to the audio library that you insert into your project. You then only have to initialize these components to make it work.\nIn its standard configuration the software has approximately 6 ms delay from input to output. This primarily due to the size of the buffers (128 samples) that the Audio library uses. One can modify Audio library constants to reduce the size of these buffers and consequently reduce this latency however this amount of latency was fine for my project; no one would put a set of auxiliary speakers that close to the main speakers.\nI decided to create my own code to interface with the rotary encoders and learn more about Arduino interrupts.\nThe OLED displays how much delay there is at each of the two outputs. There was more than enough room on the display so I also created a peak meter bar graph for the input signal. Both the Audio Adaptor board and the OLED talk to the Teensy via I2C. The Teensy has multiple I2C buses so I placed the OLED on the second bus so as not to impact the Audio Adaptor board.", "1003" ], [ "Joule Thief Torch With Casing\nIntroduction: Joule Thief Torch With Casing\nIn this project you will learn about how to build a Joule Thief circuit and the appropriate casing for the circuit. This is a relatively easy circuit for beginners and intermediates.\nA Joule thief follows a very simple concept, which is also similar to its name. It extracts or \"steals\" joules (energy) out of low-voltage systems. E.g. Most non-functional batteries actually have about 20%-30% of juice still in them. However their voltage is too low, and it is not able to power anything. The Joule thief circuit can actually harvest this low-voltage energy from batteries (or any source) and power a standard 5mm LED light quite brightly. The output is not limited to a LED.\nThis is a very easy, practical, and useful circuit to have in your house. If you can't find a working battery that you need urgently, or you want to make complete use of the batteries you buy, this would be perfect for you.\nFinally, this Instructables will also showcase a 3D printed casing for the Joule thief. However, if you do not have a 3D printer then you can check out my Laser cut acrylic box or design a casing yourself. Even just a plastic box would be satisfactory. I would not recommend leaving the circuit without a casing.\nStep 1: Supplies and Tools\nSupplies:\n1. Perf board\n2. AA battery holder (can be for 2 batteries or 1)\n3. Ferrite toroid (with two coils over it)\n4. Tactile latch switch\n5. 5mm LED (any colour)\n6. 5mm LED bezel + nut\n7. NPN transistor (I used C1815)\n8. 3mm Nuts x4\n9. 3mm Bolts x2\n10. Wires\nTools:\n1. Soldering wire and iron\n2. Wire-cutter pliers\n3. Multimeter (if you don't have one you can make one DIY. Check out my Arduino powered multimeter)\n4. Desoldering pump (optional)\n5.", "98" ], [ "Needle-nose pliers\n6. Pencil/pen/marker\n7. Superglue\nStep 2: Circuit Schematic and How It Works\nHere is a very that very nicely explains how a joule thief works:\nCREDIT TO ELECTRONICGURU FOR IMAGES\nStep 3: Securing Battery Holder to Board\n1. Using a black marker, I marked where the holes in the battery holder were on the PCB.\n2. I used the wire cutter pliers to make the holes in the perf board. Soon enough it was big enough for the 3mm bolt. If you have a handheld or electric drill this process is a lot easier. It is important to test if the holes are big enough for your bolt.\n3. I added an extra set of nuts between the perf board and battery holder to stop the bolt from protruding out of the other end so much.\n4. The two remaining screws were used to secure battery holder onto the perf board.\nStep 4: Understanding C1815 Transistor\nSome transistors have different schematics and pinouts. Therefore, just as clarification, I wanted to state which pins of the transistor are base/collector/emitter\nMoving from left to right with the flat side facing you, the pins are base, collector, and emitter in that order. This is exactly as what is shown in the diagram.\nStep 5: Preparing Ferrite Toroid\nI got the ferrite toroid from a broken RC car circuit\n1. Taking thin enamelled copper wire I wound the coil around the ring-shaped ferritetoroid 7 times. See picture\n2. The wire was cut after 7 coils with length to spare for soldering and connections. The second coil started in the same place where the first coil was started. Following the shape of the first coil, the second coil also was pulled out after 7 winds and cut with excess.\n3. To differentiate between the coils coil 1 had much longer legs than coil 2.\n4. Since my ferrite toroid was very small, I used a very thin copper coil wire. Most likely 26 SWG. If your toroid is bigger then you can use bigger and even normal wires\n5. After this, you would have 4 different wire ends. 2 for coil 1 and 2 for coil 2. These 4 can also be written as 2 for the starting side and 2 for the end side.\n6. To simplify remembering the coils, I gave the following names to the coil ends. S1, S2, E1, E2. The S and E stand for start side and end side. 1 and 2 stand for the coil number.\n7.", "611" ], [ "BEAM Solar Powered Pummer (Heart Shaped PCB)\nIntroduction: BEAM Solar Powered Pummer (Heart Shaped PCB)\nThis is a project that I have been meaning to finish for over a year now. it is a heart shaped, BEAM based pummer circuit I made to charge up during the day and flash like a heart beating at night. The solar engine is a SIMD1 solar engine by <PERSON> and the pummer is a modified version of his power saver flasher which flashes 2 LEDs off the one oscillator.\nSee:\nhttp://solarbotics.net/library/circuits/bot_pummer...\nhttp://solarbotics.net/library/circuits/se_noct_SI...\nMy final design lasts about 3 hours from when the sun starts to go down.\nI personally love creating PCBs as a step up from breadboard or perfboard circuits, and I especially like designing PCBs that go a little beyond just connecting components. Hopefully through this Instructable you will see that while a PCB designer such as Eagle can be superbly powerful, creating a functional and aesthetic circuit such as the one presented here can be quick, fun and really accessible. I spent a day designing it all and only spent around $30USD on the PCB and components! Granted I already had assorted resistors, caps, and a soldering iron.\nStep 1: EDIT: What Is a Pummer?\nIt seems in the comments that there is a little confusion as to what a pummer is, which is very fair.\nBEAM robotics is a \"style\" of analogue circuit building, popular in the late 90s and early 2000s. BEAM circuits use minimal, analogue components, often to complete simple and very organic tasks. In BEAM robotics, a pummer is a type of circuit that displays a pattern of lights or sounds.\nSee the Wikipedia pages for a broader overview here:\nhttps://en.wikipedia.org/wiki/BEAM_robotics\nhttps://en.wikipedia.org/wiki/Sitter_(BEAM)\nStep 2: Prototyping\nThe first step is to prototype the circuit on a breadboard.", "982" ], [ "I used a design almost exactly the same as Wilf's pummer from the link in step 1 however I replaced a 100k resistor at the output of the pummer with an LED and added a resistor between the output capacitor and the output LEDs to get a less bright, but longer flash. You can see here in the second photo the waveform at the node between the output LED and resistor in Wilf's original design. The peak above 2.2v is where the LED lights and the dip below just dumps charge through the 100k resistor. In my revision seen in photos 3 and 4, both the peak above 2.2v as well as the lower peak create a flash (because the voltage is being regulated to ~2.9v by the blue LED, in photo 4 you can see the other 2.2v difference, this time between the 2.9v rail and the node between the output LEDs). This revision does mean that the reference voltage LED does have to be a higher voltage than your output LEDs (and hence the circuit will run for less time) however there is less wasted charge. I like this way better however 2 oscillators, with the second acting as a slave to the first and using something closer to <PERSON>'s original circuit would also work. Just let me know if I can clarify any of this and excuse the photos of the oscilloscope screen, I had some trouble saving to USB.\nAs I was almost following <PERSON> design exactly, I mostly used this step to calculate what value components I was looking at using to make the flashes beat at a heart-like rate.\nOnce I had the circuit operating as expected I used this circuit to calculate roughly how long my pummer would last once it started flashing at night.\nTo calculate how long our circuit will last we can use 2 formulas based on the charge stored in, and the charge leaving the storage capacitor.\nFirst we know that Q=CV that is, the charge in the capacitor, \"Q\", is equal to the capacitance x the voltage across the capacitor.\nWe also know the formula for current I=Q/t where \"I\" is the current, \"Q\" is charge and \"t\" is time.\nRearranging these we can get I=(C*ΔV)/Δt where \"ΔV\" represents the change in voltage and \"Δt\" change in time (in seconds)\nHence, by measuring the voltage at one point in time and then measuring it again a certain amount of time later (I usually go about half an hour for more accurate results) we know have all the numbers on the right half of the equation and we can see how much current the circuit is drawing from the capacitor on average.", "552" ], [ "DIY Smart Home PC Ambilight\nIntroduction: DIY Smart Home PC Ambilight\nI've seen a bunch of projects online of people either building their own \"Ambilight\" for their PC's or buying them off the shelf. I recently started playing with addressable LED strips like the WS2812(b) and decided to build my own PC Ambilight.\nI make use of Apple HomeKit throughout my apartment to control various appliances such as switches, outlets, and lights, so a requirement for this project was to make the Ambilight HomeKit compatible.\nSupplies\nHardware:\n* WS2812b LED strip - Banggood link\n* 5V 3A power supply - Banggood link\n* Wemos D1 mini - Banggood link\n* Jumper wires - Banggood link\n* 2.1mm x 5.5mm DC jack (male) - Banggood link\n* 2.1mm x 5.5mm DC jack (female) - Banggood link\n* 270 Ohm resistor - Banggood link\n* Heat-shrink tubing (optional) - Banggood link\n* Header pins (male) - Banggood link\n* Header pins (female) - Banggood link\n* 4pin grove connectors - Banggood link\n* Soldering iron and supplies\n* 3D Printer for control board enclosure (optional)\nSoftware:\n* Windows\n* Homebridge for Apple HomeKit support - from this link\n* WLED to control LED strip - from this link\n* Hyperion.ng - from this link\n* Note: If you have a very big screen and require a long piece of LED strip, consider getting a 5V 6A power supply instead.\n* Note: For this project, you require a working Homebridge server if you wish to also control your Ambilight using Apple HomeKit.\n* Note: For this project, I opted for the Wemos D1 mini WiFi board. You can however use alternatives such as the ESP-01 or NodeMCU\nStep 1: Prepare Wemos D1 Mini (hardware)\nThe Wemos D1 mini is ideal as it can be powered using 5V DC, the same voltage that will power the WS2812b LED strip. You can easily swap out the Wemos D1 mini with a NodeMCU as this micro-controller also accepts 5V input voltage. Another (cheaper) alternative is the popular ESP-01 module. The only downside is that the ESP-01 module requires additional hardware as this module only supports 3.3V I/O voltages.\nIn this step, we will be preparing our micro-controller hardware.\nTo start, the Wemos D1 mini does not come with any pins soldered to it. I decided to solder some female header pins to 4 pins of the Wemos D1 mini (5V, Ground, D4, and D3). By soldering some female headers to the micro-controller you can easily interchange it later, or reuse it in other projects.\nThe Wemos D1 mini is now ready to be flashed with software to connect it to your WiFi network. We will do this in the next step.\nStep 2: Prepare Wemos D1 Mini (software)\nIn this step, we will be flashing (programming) our Wemos D1 mini with open source light control software known as WLED. Programming ESP8266 based devices like the Wemos D1 mini is very simple. I created an Instructable on this topic that can be found at this link.", "485" ], [ "I will however briefly go through the process below, but for all the details, please refer to my other instructable.\nSince we are working with a Wemos D1 mini, we can connect our board to our computer via a micro-USB cable.\n1. Connect your Wemos D1 mini to your computer through a micro-USB cable.\n2. Open your preferred flashing tool, I use Tasmotizer.\n+ Make sure that your port is correct. Also, since we are using a Wemos device in this project, make sure that the \"self-resetting device\" option is on.\n3. Download the latest binary of WLED (I use the WLED_x.xx.x_1M.bin file) - Link to WLED releases\n4. Select the WLED firmware file just downloaded in your flash tool.\n5. Now you can proceed to flash the firmware. In Tasmotizer, click \"Tasmotize!\". If you are using another flashing tool, proceed to flash the firmware to the Wemos device.\n6. Wait for the WLED firmware to be flashed to your device, this can take some time.\n7. Once you received a message that the firmware is successfully flashed, you can restart your device.\nIn the next step, we will be configuring our Wemos D1 mini to connect to your WiFi network.", "854" ] ]

[ 440, 5075, 4988, 11256, 11276, 2894, 7855, 6168, 2951, 2716, 10175, 2292, 11145, 4428, 2965, 11320, 4312, 3607, 6089, 3777, 11138, 2804, 1395, 2485, 559, 8312, 9865, 7116, 9888, 10752, 21, 3367, 7923, 8965, 8981, 5534, 10099, 3369, 4011, 3502, 6614, 10377, 9291, 8435, 8511, 10746, 4091, 5454, 6404, 865, 143, 10164, 1784, 3619, 4719, 10972, 3432, 10655, 8686, 3907, 7687, 9094, 7843, 7678, 5110, 2374, 4550, 3074, 515, 10714 ]

[ [ "I slowly uncovered my hand and tried to control my tension. The stakes were high, not unreasonably so, but still high enough that I need to win this or the next round or I would out. And broke. Across the table <PERSON> had a face like a glacier, as always. He seemed to be breathing a little bit deeper than usual, though Did he have a good hand, maybe a better one than me? Or was he just feeling how close he was getting too close to the edge of losing again this round? Does he notice my tension? To the left of me, <PERSON>'s eyes darted from left to right, as if unsure about everyone, including himself. Only <PERSON> was relaxed, ogling the waitress like all the time, inquisitively raising an eyebrow at me as he noticed me watching him. He appeared to be care as little about this game as he did about the ongoing divorce from his wife.", "417" ], [ "Admittedly, the only time one has ever remembered <PERSON> getting emotional, even violently raging, was when he has discovered a tiny scratch on his beloved Lincoln Continental.\nNote that this has been suggested by <PERSON> already (\"focus on the people\"). I suspect that this will work well in the \"first person perspective\", possibly enticing the reader to somewhat identify with the narrator (and his goals and feelings). However, it should also work if told by omniscient third person, albeit with more emotional distance. Note my crude attempts to convey a little bit of insight into the emotional background of the other players, but less than a omniscient observer could provide.\nWe tried to control <PERSON>, but he was too strong in his rage. I had had no idea that my innocent remark about his divorce would throw him in a frenzy like as if someone had totaled his Lincoln. Suddenly, he collapsed into a weeping pile inside his expensive clothing, and I felt sorry for him - all his wealth and all his luck during the poker match had not protected him from the harsh truth about how deeply he loved his wife.\nYep, even the other players are vulnerable to strong emotions.\nThis is just meant as an example on how to possibly convey some sort of emotional tension by adding a bit of background and chatterer to the characters. I am no writer, and neither do I recommend to write <PERSON> style (well, I tend to somewhat long sentences but I am still far away from <PERSON>).", "86" ], [ "As a minor counterpoint the the existing answers, it is also possible for realistic ammo to ruin a scene. The audience is willing to assume that certain events that don't impact the narrative occurs offstage. As a classic example, the eating habits of the characters of Middle Earth are explained in great detail, but no one ever needs to relieve themselves afterwards. It's something that we all recognize probably need to happen, but including this aspect of realism would only detract from our engagement. The audience is often willing to believe that a new clip was loaded while we were paying attention to something more important.\nMy other example contains spoilers for the 1985 film Alien Outlaw. Consider yourself warned.\nAt the climax of the movie, the sharpshooting heroine is fighting against the last remaining alien. The directory takes great pains to inform the audience that she is down to three bullets. She can't shoot at the alien, because she might miss, and she only has three bullets. She needs to move to a better vantage point, because she only has three bullets.", "900" ], [ "Of course, having reached this vantage point, it would be unsatisfying for her to shoot the alien and say \"I guess I have some extra ammo left over\", so the first shot misses. Nothing has changed about our protagonist's situation, but the film believed that the tension has ramped up, because she now has two bullets, which is an even smaller number than three. Having discovered this tension building device, the movie immediately pulls it again with another failed shot, leaving her with one bullet. Unsurprisingly, this final bullet succeeds where the other two failed and kills the alien. If this paragraph was painful to read, I assure you that the scene was more painful to watch.\nNow, I'm not saying that limited ammo can't create tension. Plenty of examples have been given about how this can work. I'm just providing a reminder that limited ammo doesn't automatically create tension. When every bullet matters, the limits are tense. When only the final bullet matters, the limits are an accounting exercise.", "900" ], [ "On evolution statistics\nThis basic evolution theory question has been haunting me since childhood and I'm kind of embarrassed that I can't explain it yet:\nConsider a butterfly. It's wings have evolved to look like the eyes of an owl, so to prevent it's predators who are themselves preys of the owl to attack it.\nFrom what I've learned (and feel free to indulge me in the very basics if I get this wrong), natural selection suggests that the butterflies that didn't have the owl's eyes in their wings would be eaten, leaving the ones with the eyes to survive, right?\nBut that implies that this useful trait appeared in the butterfly's wings by chance. Now, I know trillions of butterflies have been born before this, but trying to figure out the possibility of this to happen by chance doesn't look like it's plausible. Let's go through the things that have to work right before this trait is passed over:\n1. For a butterfly to be born in a different wing colour, it should be a genetic mutation which doesn't happen this often, for what I know.\n2. The wings are composed of micro-scales. For every scale to compose an image so similar that confuses even us, the margin of error is very slim. It could be anything.", "429" ], [ "It could be a picture of <PERSON> for all we know. The scales must be in the correct spectrum of colour by a small margin of error. So that is already a very unlikely thing to happen.\n3. Then, this butterfly cannot be eaten out of bad luck (mind you, the wings don't guarantee it will not be eaten, just enlarge her chances).\n4. It has to mate, which also is not a guarantee to happen, since nature deals with competition. If this butterfly we are considering is a male, the female must find the wings hot, instead of being afraid of those creepy eyes.\n5. The genes of this mutations must also be dominant, so when it mates and generates offspring, at least part of the new butterflies inherit this trait.\nAnd this is a simple example. There are animals that evolved so smartly I can't even start to think of the possibilities.\nMy question is, more precisely, how likely is it for a species to evolve into complex solutions?", "429" ], [ "<PERSON>\nA deadbeat dad joins the Russian space program so that he can come back a hero and actually *be* something to the son he abandoned. He comes back with an alien inside him that comes out at night and eats the most vile of prisoners.\nThis is a pretty forceful statement about the male psyche and the violence wrought upon it when it becomes part of anything that the military has an interest in. Even the most un-\"heroic\" actions, like going to space (\"sitting in a tin can\", as one character refers to it) are inseparable from the military's goals of control through deadly weaponry, and give support to the deaths of people.", "999" ], [ "This is <PERSON>'s (the woman scientist) philosophical opposition: no matter how vile the criminals are, they are still people.\nAnd so, on the level of the individual male, the honor he hopes to gain in his child's eyes by being a hero (or maybe the ability to provide that comes with being a national hero) is revealed to be useless, and a deadly detour from actually being, you know, anywhere physically near the child to do anything for them. The man wants his son, and is ashamed of how the military turned him into a monster and made the world that less safe for all children.\nThe alien feeds on cortisol, produced when humans are afraid. The military feeds on fear, and puts this alien into every man who signs up to be any kind of soldier.", "295" ], [ "Fears\nJust by looking at the ratings here, Los miedos hits a nerve. My 3½/5 is rather generous to be honest. The one available copy I could find appeared to be cropped for TV and the subtitles, machine-translated then AId from Spanish to English, were by times gibberish. So there, my reason to give this film the benefit of the doubt.\nWhat is beyond hope is a lot of the rest. We follow seven characters, immune to some sort of plague and doomed to find a way southbound, out of a government-controlled region, towards safety.", "369" ], [ "The women – a whore, a nun, a very pregnant woman with a very unconvincing bump, and an old lady – are all going through their own stage of hysteria and someone's idea of womanhood. The men – a macho, a mummy's boy, and someone's idea of a (pardon my French) retard – try to balance that out with machismo, sycophancy, and retardation respectively.\nOne beautiful scene, and the one reason to watch, happens in a salt desert. The nun takes charge, and shoots her god. That's when it should have been it over. No hope, no future. Amen.", "342" ], [ "Whenever one encounters great art - whether written, filmed, painted, or other - it should be kept in mind that very little of it is accidental. Without going into the merits of the Peabody Award winning series, would you think <PERSON>, for example, or <PERSON>, or <PERSON> wrote works with entirely unintentional outcomes?\n<PERSON> has often been quoted as saying that he was fascinated by the idea of taking a protagonist and turning him into an antagonist (Mr. <PERSON> becomes <PERSON>):\nThe idea of a kind of <PERSON>, milquetoast character who reinvents himself and turns from somebody good to somebody bad and profits in the process. That was the sum total of the concept.\nThe setting of the protagonist being a meth-cooker came from a quip made by a fellow writer when they were both unemployed, that they should cook meth out of an RV to make ends meet.\nGood writing is intentional (quotes from here on are from <PERSON> himself).\nHaving said that, in hindsight, my good fortune was that I didn’t have the opportunity to go with my first instincts and throw the kitchen sink plot-wise into our first season. If I’d done that, I would have painted myself into some seriously unpleasant plot corners. ... People still like storytelling that can slow down enough to explore characters and examine them closely. I think there’s still room for that.\nGood writing, however, can't prevent misinterpretation by individuals or by changing mores in culture.\nI will admit that a great many of the interpretations that people have of [breaking Bad and Better Call Saul] involve details and conclusions which — frankly — I never had in mind.\nIf our culture ever becomes one in which we see the death and destruction of many innocents as a perfectly acceptable collateral damage in order to \"rid the world\" of some junkies, gangs, and meth empires, then maybe society will come to see that ol' <PERSON> wasn't so bad after all.\nBut that was not <PERSON> vision. He wrote a series in which a faulty protagonist becomes a vicious antagonist who destroyed everyone around him.\nClearly, though, certain people were killed for the greater good:\n<PERSON> is actually in a weird way kind of likable, but he just had to go. <PERSON> had to go.", "861" ], [ "<PERSON>, as we like to call him. I think the whole world is better off without that group of characters. ...the character of <PERSON> – we were all champing at the bit to see her get her just desserts much more than <PERSON> even.\nUltimately the story is not about the good done to society in doing away with bad people, but the bad things broken people can do. He ruins people's lives, everyone who is close to him.\n(On choosing an ending for <PERSON> in which he was afforded a sliver of redemption before dying:) We didn’t feel an absolute need for <PERSON> to expire at the end of the show. Our gut told us it was right. ...I guess our gut told us that it would feel satisfying for <PERSON> to at least begin to make amends for his life and for all the sadness and misery wrought upon his family and his friends. <PERSON> is never going to redeem himself. He’s just too far down the road to damnation. ...When you think of it, [<PERSON>] didn’t really have a chance in the early days. <PERSON> said, ‘You either help me cook meth and sell it, or else I’ll turn you in to the DEA.’ So this poor kid, based on a couple of really bad decisions he made early on, has been paying through the nose spiritually and physically and mentally and emotionally. In every which way, he’s just been paying the piper...\nTL;DR: No, I don't think <PERSON> thought <PERSON> was kinda good for society.\nBreaking Breaking Bad\n'Breaking Bad': Creator <PERSON> explains series finale", "86" ], [ "Dog Day Afternoon\nThank God I did not know anything about this movie because the experience I just had was transcendent.\nThe opening was so funny I was asking myself if this had been a comedy all along, until I realized that the absurdism was just a reality of the overall situation. It’s funny, yes, but it’s also tense and thrilling and tragic all over, to the point where I sobbed my eyes out during that one phone call towards the end.\nWhat a heartbreaking little moment that oddly encapsulates the personal cost of queerness, the lengths to which society can push you by means of rejection.", "471" ], [ "When a society doesn’t afford you dignity, you are forced to demand it.\nAlso, the actual bank robber <PERSON> is playing was as hot, if not hotter, than <PERSON> himself. No wonder the tellers were like “whatever you say, handsome”. Like, same.", "86" ], [ "Vengeance Is Mine\nTwice, hair-cutting is used as a form of abuse. Both times it is very harrowing, but the blade never punctures the skin. That's the fine line <PERSON> walks throughout this melodrama.", "1009" ], [ "It is sleepy and mundane but with every burst of drama, it thwarts expectations (reminds me of something <PERSON> said at a Q&A the other day, that he doesn't make genre films; he makes emotional ones). Upon learning that this film used to be called \"Haunted,\" I remembered <PERSON> asking <PERSON> if she is afraid of ghosts, as one lives in the bedroom she would occupy. I see now that she meant her mother, <PERSON>.\n35mm.", "61" ] ]

[ 382, 6298, 3632, 1636, 9074, 2962, 8715, 10172, 9544, 8481, 5609, 3035, 3483, 6784, 10423, 804, 11208, 3625, 2750, 3888, 10108, 4824, 1280, 9925, 1007, 10244, 5280, 7375, 5119, 2225, 135, 7278, 10652, 1351, 11313, 322, 8828, 3267, 6786, 3569, 727, 9906, 3914, 4783, 10616, 7801, 9071, 1338, 4865, 7809, 6082, 2298, 6392, 352, 4571, 5301, 9517, 8615, 5554, 10653, 7898, 452, 11012, 11156, 10448, 11167, 2147, 6930, 4323, 2384 ]

[ [ "Get Lost in a Good Book: a Simple Book Nook in 9 Steps\nIntroduction: Get Lost in a Good Book: a Simple Book Nook in 9 Steps\nHave some old, damaged books? Want to bring your favorite scenery or setting into your home?\nSupplies: a hardcover book, rigid foam/posterboard/heavy\nduty non-corrugated cardboard, decorative paper (I used encyclopedia pages for a black and white canvas)\nTools: Glues (stick glue, hot glue, liquid Elmer’s/school glue), markers or translucent paints, x-acto knife\nStep 1: Choose the Book\nFind a hardcover book, preferably one with an intact cover and spine, but damaged or missing pages. I found a box of Westerns by the roadside after a hard rain. The pages were already brittle, and now moldy too. Don’t sacrifice a book you love or a book that still has life in it.\nStep 2: Remove the Text Block (Pages)\nFold the front and back covers back to expose the area where pages meet the spine. Carefully slice through the endpapers (and not the spine). Set the text block (chunk o’ pages) aside. If you want to paint or decorate the cover, do so now and let it dry.\nStep 3: Cut Panels\nUse the text block as your guide to cut reinforcing panels.\n1. The front and back should be the same size as the text block’s (and a bit smaller than the covers).\n2. The spine should be the length and width of the text block’s, but slightly shorter at top and bottom (I took 0.25 inches off both ends).\n3. The ceiling and floor pieces should be narrower and shorter than the text block’s. The goal is to make them sit flush within the other foam pieces. You may need to make slight adjustments to ensure the book closes properly, with front and back covers parallel, not splayed.\nStep 4: Cut Paper for the Panels\nWrap the fronts and edges of the cover and spine pieces in your chosen paper.\nI used encyclopedia pages as they had black text on a white background, and the paper was like onionskin. This kind of paper didn’t add bulk, but I did worry about the markers/paint bleeding. If you want to use watercolors, I recommend applying a clear gesso first. Don’t use newspaper—it will yellow and disintegrate.", "6" ], [ "You can use the pages that you cut out of this book if they are flexible, but mine were crumbling.\nTrim paper to size, leaving an overlap to glue to the backsides of the foam pieces. You can fold or cut the corners to get a clean, mitered edge.\nStep 5: Glue the Paper to the Panels\nGlue the paper to the foam panels on the front, edges, and wrapped around to the back. I used Elmer’s stick glue, as liquid school glue would cause wrinkles and hot glue would leave lumps. Let dry.\nWrap the ceiling and floor pieces completely in the paper, as their insides and outsides will be visible. Aim to have the seam/overlap near the long edge of the panel.\nStep 6: Glue Three of the Panels to the Hardcover\nWith the book spread open, hot glue the backs of the cover and spine panels to the hardcover interior.\nDo not glue the ceiling/top or floor/bottom panels yet.\nStep 7: Decorate!\nDecorate! I chose my favorite local scenery, as I find the same kind of peace there as I do in a book. Keep in mind the scale – small trees at the back, objects appear larger closer to you. If you want any 3D elements, decide how you will make them.\n1. Waterfall: I cut 6 skinny strips (approx. 0.5 inches wide), colored them blue on the front and back (using two different markers), then braided them. Braid gently, as the paper may tear. I then glued braid #1 at the top of the spine panel. I glued the braid #2 at the base of the spine panel. I then glued braid #1 to the spine, just above where I glued the start of braid #2. I curled the ends of braid #1 around a pencil to help form the foamy that collects at the base of a waterfall, and left them loose. I glued braid #2 down in a few spots along the floor panel to ensure it didn’t unravel.\n2. Pine/conifer tree: I cut then colored a 2-inch-wide strip of paper green on the front and back (using two different markers).", "6" ], [ "Faux Snow Globe Gift Jars\nIntroduction: Faux Snow Globe Gift Jars\nI used to put Christmas treats in glass jars - candy, party mix, recipe fixings. People would ooh and ahh, eat the contents, and what did they have? An empty jar. They should be left with something worth keeping, something they could cherish.\nAHA!\nA Faux Snow Globe Jar! What this Instructable presents is a way to combine several of the crafts I make (Some are Instructables I have shared) and other techniques to make something that was a big hit at my Elves' Fanily Workshops at several libraries (the motto - \"Why should elves have all the fun?\").\nSupplies\n* Mason-type jar or any lidded glass jar. For this Instructable, I used a pint/2 cup/16-ounce jar. The Gallery samples are quart/4 cup/32-ounce jars\n* Clear shot glass, plastic tumbler, candle holder (The sample for the how-to uses a candle holder), or half of a plastic fillable ornament (The Gallery at the end uses half-dillables)\n* Cotton ball (a.k.a. Cotton Wool)\n* Candy, party mix, cereal, nuts, raisins, pretzel sticks, recipe ingredients, or anything you wish to put inside the gift jar\n* Hot glue gun and glue gun sticks\n* Ribbon\n* Decorations: pompon balls (1/2 inch: a pompon is a small fluff ball, a pompom is a large artillery cannon), small plastic figures or toys\n* Scissors\n* Measuring tape or ruler (to see how wide the lid is, and to measure possible globe toppers)\nSupplies for:\nTree\n* Green paper or construction paper, cut to a 3-inch square\nSnowman\n* 3 pompon balls\n* 2-inch piece of brown wire or a thin twig\n* Black and orange markers\n* Yarn\nSkier\n* Wire, plastic-insulated, 20-24 gauge\nStep 1: Making the Tree\nFor more complete instructions, follow the link to the Kirigami Christmas Tree in Green Instructable.\n* Take the 3-inch paper square (larger, if you have a larger snow globe cup) fold it on the two diagonals, turn it over, and fold it on the two medians. Collapse it to four triangular flaps.\n* F,or each flap, press it in along the fold to make it tlaplets. When each flap has been doubled, trim off the lower tails to leave a triangle.\n* Make two sets of cuts from the edge toward the center, but not all the way. (In the Instructable, using an 8.5-inch square, four sets of cuts are made. With a smaller square, four cuts would be too close)\n* For each of the lower cut segments, fold the upper outside corner until the fold touched as close to the bottom of the segment as possible. Repeat this with all the segments of each flaplet.\n* Fluff it out, stand it up, and you have a little tree!\nStep 2: Making the Snowman\n* Hot-glue two of the pompon balls together. Glue a two-inch piece of wire onto one end of the balls for arms.", "644" ], [ "Glue the third ball to the wire.\n* Using a black marker, make dots below the arms for coal buttons. Make dots above the arms for the mouth and eyes. Use an orange marker to make a dot for the carrot nose.\n* Take a short piece of yarn, unravel it , and separate one ply from the rest. tie it around the neck of the snowman as a scarf, and trim the ends to the length you think best. You now have a snowman!\nStep 3: Making the Skier\nFor more complete instructions, follow the link to the Wire Skier--a Suji Project Instructable. The dimensions here are smaller, because the space on a pint jar is less.\n* For the skeleton/armature/skis, fold a 16-inch piece of wire in half, and in half again. Fold a 16-inch wire in nearly half for the top and sleeves. Wrap the shorter half up 5 times around the four core wires. Fold down one core and wrap out the arm 10 times. Wrap the longer half up around the first set of wrappings 5 times. Fold down another core and wrap out that arm 10 times.\n* For the pants, fold another 16-inch wire in almost-half. Wrap the shorter half down the core 3 turns, divide the lower core into 2 groups of 2, and wrap out one leg 15 times.\n* Wrap the longer half down, around the first wraps, 3 times. Wrap the other leg 15 turns.", "879" ], [ "DIY Mini Wood Crate Tabletop Christmas Tree\nIntroduction: DIY Mini Wood Crate Tabletop Christmas Tree\nUsing only what I had on hand, I used 12 mini wood crates and a few other supplies to make a tabletop alternative Christmas tree.\nSupplies\nLinks to the products we used as well as the original post can be found here.\n3/8 Wood dowel\n(12) mini crates\n2” thick straight dry/aged branch\nRust-Oleum Imagine Spray Paint, Shimmer Emerald\nBehr Chalk Spray Paint, Tin White\nDecoArt Galaxy Glitter, Clear Ice Comet\nExcel Blades Metal Mitre Box Set with Heavy Duty K5 Handle and Razor Pull Saw Blade, Small Mitre Box and Saw with 2 Cutting Angles for Wood and Soft Metal\nHot glue gun\nBernzomatic Torch\nSurebonder Light Tacker\nOrnaments\nStep 1: Watch the Video!\nFor full details please visit our website.\nStep 2: Prep the Branch Pieces\nThe branch I used was about 2 inches in diameter. I used a miter saw to cut (six) 5-inch pieces. The branch had been outside for a while so cleaned it up by scraping off any loose material.\nTo <PERSON> finish the pieces, I set them on top of a terracotta pot, away from anything flammable, and used a Bernzomatic torch. After torching I scraped away any white ash.\nOnce dry the pieces got a little sparkle with a coating of DecoArt Galaxy Gitter. This paint goes on cloudy but dries clear so all you see is the glitter.\nStep 3: Prep the Crates, Paint, Add Staple\nBoth mini and full-size crates are really rough. To get a fine finish you'd need to do a lot of sanding. The finish was going to be more rustic so I only did a little sanding. The crates I used needed the most sanding inside of the side openings.\nThe wood dowels also were sanded, but mainly to remove the sticker residue.\nTo hang an ornament in each crate cubby, I added a light tacker staple.", "401" ], [ "These staples have a raised area that is perfect for a single ornament hook.\nThe hooks I used are upcycled springs from the mattress support of a baby crib. They were spray-painted with the same green metallic paint used on the tree overlay.\nStep 4: Assemble the Crates\nAll the crates were assembled with hot glue. Each row was hot glued and then the rows hot glued to the previous row, pyramid style. The bottom two crates are actually laid lengthwise.\nStep 5: Make the Tree Overlay\nThe overlay is made with 3/8 inch wood dowels. All cuts are made with the mini saw and miter box (see list of materials used.)\nThe pieces were clamped into place, hot glued, and trimmed with the mini saw. Once the tree pieces were secured together, it was sprayed with Rust-Oleum Imagine in Shimmer Emerald.\nThe last step was to hot glue it to the front of the crate tree.\nStep 6: Decorate\nWhile the tree was laying down, I added three sets of battery-powered light. I put them through the opening closest to the back of the crates, evenly distributing the lights in the individual cubbies. The top two levels share one set of lights.\nAdd the hooks and ornaments, turn on the lights and enjoy.\nFor more projects from us, please join our weekly newsletter here!", "6" ], [ "DIY Halloween Cornstalks\nIntroduction: DIY Halloween Cornstalks\nCreate homemade cornstalks for interior or protected exterior projects from simple items.\nSupplies\nYou’ll need: PVC Pipes, Brown Packing Paper roll, masking tape, tan spray paint, and scissors.\nStep 1: Start Creating the Leaves.\nGet a roll of brown packing paper at your local home improvement store. (Usually about $3 a roll) I tore off quite a few sheets about the same size...maybe about 1-1.5 feet long, just depends how big you want the leaves to be. After you tear off the sheets, stack them and fold them in half, longwise. I then cut out a leaf shape through all the sheets. By folding it in half, you can get double the amount cut in less time.\nStep 2: Spray the Pipes.\nCut your PVC poles to the height that you prefer. I made a bunch of random height stalks because I was going to use them for a couple different types of displays.", "6" ], [ "Then spray the base pole with the spray paint so the white doesn’t show.\nStep 3: Crinkle the Leaves and Attach.\nSo after the leaves are cut out, you’re going to grab a stack, maybe 6-10 sheets, and literally crinkle them up with a twist in your hands. You want them to wrinkle. After you crinkle them all, pull them apart so you have a box or stack of crinkled sheets, read to attach.\nNext, grab one of the sprayed base poles from previous step and wrap one leaf around the top of the pole and secure it with masking tape. Use the wider end for the pole and the pointy end hanging off the pole, then shape by hand so it points out and away from the pole.\nNext wrap the next leaf around the base of the previous leaf, covering the tape so it’s hidden. Then continue this pattern all the way down the pole, adding as many leaves as you desire.\nAt the base, I used some extra paper and crinkled it just to wrap around the very bottom of the stalk and taped it in place.\nStep 4: That’s It!\nYou’re basically done at this point. I’ve attached some images of the projects I used this for.", "984" ], [ "Make Boxy Stuff Out of Obsolete Business Cards!\nIntroduction: Make Boxy Stuff Out of Obsolete Business Cards!\nFor this Instructable, I will teach you to use obsolete business cards as a versatile construction set. You can make everything from a single small box, to various Tetris pieces and even a gigantic Menger sponge. No glue or cutting needed, just simple folding!\nYou will likely get into trouble if you use current business cards from your employer, but instead consider doing as I did several years ago: when my then ex-employer was about to move to a new office, I asked people to give me their outdated business cards (which would otherwise be discarded) so I could use them to build things! I now have a stockpile of thousands of cards to build with!\nSupplies\nObsolete business cards (please don't use new ones!)\nStep 1: Assemble a Basic Cube!\nEach uncovered cube consists of six business cards, plus an additional six to cover the outsides. Take a pair of cards, lay across each other with the print side together, making a plus sign. Press and fold down the edges to make two cards shaped like a \"[\". Repeat this until you have six cards with folded sides.\nAssemble the six faces together, using the folded sides to \"hug\" the sides of the others. The construction will be loose until the last card is slid in, holding everything in place.", "966" ], [ "No glue necessary!\nTo finish an exterior face, fold up an additional \"[\" cards and then anchor it to the tabs on one side. On the other side, give the tabs \"dog ears\" to make the next step easier. Now \"tuck\" the loose edge into the tabs. If you have difficulties with this step, you can slightly crease or curve the edge to help guide it in during the tuck. Using business cards with thinner stock can also help in this step.\nStep 2: Connect Cubes to Build Complex Shapes\nTwo assembled cubes can be connected by locking together the tabs on uncovered cube faces, but this is rather difficult to execute properly.\nThe alternative is simply to build a cube onto an existing cube, by adding six cards, in the same basic sequence as you would build a basic cube. I prefer the latter method, as I find much it easier to execute (it is even easier than building the first cube, because the first cube holds everything in place!)\nStep 3: Have Fun With It!\nInvite your cat! Cats love boxes, cats adore Menger sponges! Make a life sized Tetris pieces or build a home for fuzzy creatures or miniature figurines!\nThe choice is yours, think outside the box!\nInspiration:\nThank you to Dr. <PERSON> and her HUMONGOUS Menger Sponge for making me aware of the technique and inspiring me to make my own! You are my hero!", "276" ], [ "Phases of the Moon Wheel\nIntroduction: Phases of the Moon Wheel\nI was looking for something simple with minimal materials that our students could create and learn about the phases of the moon. After a couple of prototypes, I settled on this format. Hope your students enjoy making it.\nSupplies\nA black piece of construction paper, 45cm x 30cm\nA white piece of standard size paper\nPaper clip or compass\nStraw\nCircle template, 4cm diameter\nTape\nRuler\nPencil\nScissors/craft knife/Exacto knife\nEraser\nStep 1: Fold the Paper\nFold the construction paper in half so that it is approximately 22.5cm x 30cm.\nStep 2: Finding the Centre Point\nOn one side of the paper, located the centre point by drawing diagonals from opposite corners and make a pencil mark.\nStep 3: Draw the Phases Circle\nFrom that centre point, draw an 8cm circle using a compass or paperclip.\nStep 4: Horizontal and Vertical Lines\nWith the fold at the bottom, draw a horizontal line through the centre point. Both ends of this line should be at the midpoint of the edges.\nDraw a vertical line through the centre point that is perpendicular to the horizontal line that was just drawn. At this point you can erase the two diagonal lines used to find the midpoint.\nStep 5: Make the Phase Sections\nDraw two lines through the centre point which bisect the 90-degree angles created by the horizontal and vertical lines. This will create eight sections that will measure 45 degrees each.\nStep 6: Drawing the Moons\nAt each point where the 8cm circle intersects with the lines drawn in the previous instruction, draw 4cm circles using a compass or 4cm template. Use the intersection point as the centre of the circle. Once complete you will have eight, 5cm circles drawn around the larger 8cm circle.\nUse a black marker to trace the 4cm circles.\nStep 7: Drawing the Phases\nWith a pencil, draw the phases of the moon inside the 8 circles with the “full moon” on the left circle.", "294" ], [ "Make a mark on the pieces that will need to be cut so each circle shows the appropriate phase. You can erase some of the straight lines outside the 4cm circles.\nNote: you will cut out the portion of each circle that is visible in the “phases of the moon” picture.\nStep 8: Cutting Out the Phases\nCut out the parts of the moon phases but don’t cut through the back page. Open the page up while cutting out the parts.\nPoke a pin hole through the centre point so that it marks the second page.\nStep 9: Make a Straw Hole\nOpen the page and make the pinhole on the second page large enough to fit a straw.\nStep 10: Making Moon Phases Visible\nUsing white paper, cut out a circle large enough to cover all the moon phases. You can use the same paperclip or compass for this but make sure you cut the circle a little larger. To find the middle point draw diagonals from each corner.\nTrim the circle so that when placed on the moon phases the white section only covers one phase. The shape will be like a keyhole or rectangle.\nStep 11: Add the Spinner\nMake four vertical cuts in one end of the straw then fold each piece/tab so they are perpendicular with the straw.\nPlace the straw on the centre point of the white paper and tape down the tabs. If you spin the straw, the white paper should spin with it.\nInsert the non-cut end of the straw into the hole that was made on the second (or back) black page.\nStep 12: Test It Out\nClose the black paper and rotate the straw. The white page should show through each moon phase as it rotates.\nStep 13: Write the Phases on the Wheel\nRemove the straw and white paper then write the moon phase next to each location in white pencil crayon or marker. Now you can reinsert the straw and test it out.", "6" ], [ "Enlarging an Image Using a Grid\nIntroduction: Enlarging an Image Using a Grid\nAny home brewers out there?\nI am the king on mediocre home brewing and I'm going to show you how I enlarged one of my beer labels using a simple grid method.\nSupplies\nMaterials\n-Print out the image to enlarge\n-Scissors\n-Boxcutter\n-Ruler\n-Pencil\n-Red marker\n-Black marker\n-Paint\n-Paint brushes\n-Top coat\nTools\n-Jigsaw\n-Orbital sander\nMolding\n-Silicone molds\n-Polymer clay\n-Wood glue\nGold leaf\n-Gold leaf\n-Gilding glue\nStep 1: Draw the Grids\nYou totally remember the \"grid method\" from elementary school, but it basically involves drawing a grid over a reference picture, and then drawing a grid of equal or larger ratio on something else. Once the grids are finished, you draw the image on the new canvas focusing only on one square at a time.\nI doubled my image. I drew a 3x3cm grid on the printout of the beer label and made a 6x6cm grid on a piece of plywood.\n*You'll need to draw the exact same number of lines on the canvas as you did on your reference picture, and that in both cases, the lines must be equally spaced apart.\nIt's super easy and the best part is this is a low-tech, kid friendly way to draw any picture you like.\n*To help yourself focus on a square, use a boxcutter to cut out a matching square in a sheet of paper.\nStep 2: Cutting\nI used a jigsaw to cut out the oval and then I sanded it down.\nStep 3: Clay Moldings\nCreating polymer clay molding is easy!\n-Press polymer clay into the molding, filling every nook and cranny and keeping the top as level as possible\n-Paint a layer of PVA glue, epoxy resin, or gorilla glue onto the surface of where the mold is going.\n-Gently pull the clay out of the silicone mold. Don't wait for the clay to dry.\n-Paint the same glue on the back of the clay you just pulled out, and then gently press it onto the surface.\n-Let it dry for 24 hours.\n*You don't need to paint the surface first. I did, because I was trying to figure out my colors.\nStep 4: Drawing, Painting and More Molds\nI drew the image onto the wood going square by square.\nI started with the oval, painted it and continued on with the banner and \"Pilsner\" font. It was a little time consuming and I made a couple adjustments to the \"Pilsner,\" because it was too straight on the printout.\nStep 5: More Font\nI thought I could pressure engrave the font to where it would show up under a coat of paint.", "74" ], [ "NOPE! I wish I used a dremel tool. A few letters showed through, but I needed to draw arches and measure spaces since the grid was painted over. I also wish I didn't use chalk paint! Dang it! I mean, I really like how it looks, but it would probably look nicer without that chalk paint texture.\nStep 6: Gold Leaf\nFor gold leaf.\n-Brush on gilding glue and wait for it to become tacky. About 20 minutes.\n-Apply the gold leaf by placing it over the glue.\n-Remove the unused leaf by smoothing the wrinkles with your finger or a small paint brush.\n*The glue must be tacky or else the gold leaf is tough to apply. It'll slip around and get stuck to your fingers and brush.\n*Gold leaf gets everywhere too! Really....everywhere! It breaks down into little gold specks while you smooth, so keep cleanup supplies nearby and turn off the ceiling fan.\nStep 7: Finished!\nTop coat and hang!\nI'm starting to like the chalk paint texture now too. This was a really fun project and took me back to elementary school.", "959" ], [ "Magnetic Chess Board With Resin Art\nIntroduction: Magnetic Chess Board With Resin Art\nMagnetic chess boards aren't just for travel! There is something extra satisfying about your piece gently pulling itself into place on every move. And, epoxy resin transforms this into a polished work of art.\nThis is a great project for young kids, with adult support. They can pick the colors, paint the squares, add the glitter, and assemble the squares on the board. Adults should handle the magnets, drills, and epoxy resin. Your kiddo will feel total pride of ownership seeing their hard work encased in shiny glass. :)\nNOTE: Initially, we bought magnetic chess pieces thinking they'd work on our board ... but no! The polarity of the magnets was random, and only half would stick to our board. So we made our own magnetic chess pieces as well.\nSupplies\nI've included links to the products we used, for reference, but there is nothing special about them. You can also get these supplies at your local hardware store.\nOur instructions make a 12\" chess board with 1.5\" squares. Alternatively, you could choose 1\" squares and make an 8\" chess board, or 2\" squares for a 16\" chess board.\nChess board:\n* 12\" x 12\" plywood panel\n* 64 unfinished 1.5\" wood squares\n* Clear epoxy resin (approximately 10 oz needed)\n* 64 magnets for the chess board (flat circle shape)\n* Wood for legs (optional) - we cut 2.5\" lengths of a 1\" wide dowel at a 45º angle\nChess pieces:\n* Set of wood chess pieces (unweighted)\n* 32 magnets for chess pieces (small cylinder shape)\n* 32 adhesive felt circles for bottom of chess pieces\nAssembly supplies:\n* Gel super glue or any other strong glue\n* Wood glue\n* Drill and drill bits\n* Paint (one dark color and one light color)\n* Paint brushes\n* Glitter (we got a variety set to use dark and light glitter on the corresponding pieces)\n* Painters tape or masking tape\n* Clamp to hold chess pieces while drilling\n* Sandpaper for smoothing the edges of epoxy after it hardens (optional)\nStep 1: Drill Holes for Magnets, Assemble Base\nCut materials to size. Cut 12\" x 12\" foam core to size with a very sharp knife. Cut the plywood to size, if needed, and sand the edges.\nDraw lines to indicate placement of the magnets. On the foam core, use a pencil to draw a line 3/4\" from any edge. Then, draw 7 more lines at 1.5\" increments across the board. Turn the board 90 degrees and repeat this process to create 8 perpendicular lines across the board.\nLay out a few tiles on the board to ensure alignment. The lines should intersect in the center of each square on the chessboard (not the edges). You'll see in the picture I got this wrong a couple times!\nDrill holes in the foam core where the pencil lines cross.", "622" ], [ "Choose a drill bit that matches the size of your magnets (the same diameter or slightly bigger). Rip off any little bits of hanging foam. I only drilled 1/2 way through, but I think it would work fine if you went all the way.\nGlue the foam core and plywood together with wood glue. Wipe away any excess and place a couple heavy things on top until dry.\nAdd wooden legs if you like! We cut 2.5\" lengths of a 1\" wide dowel at a 45º angle. To install, we used wood glue, and then one wood screw into each from the top of the board. Make sure the screw is sunk below the top of the foam core.\nStep 2: Glue in the Magnets\nA few things to keep in mind when gluing the magnets:\nMake sure each magnet is facing the same way. Otherwise, your chess pieces will attract to some squares, and repel from others. That would be a great way to confuse your enemies. But it might make playing chess difficult.\nThe magnets should sit below the surface of the foam core. A smooth surface is important so the squares sit evenly. Have a tool ready to push magnets down without getting glue on your fingers.\nStep 3: Paint the Squares and the Base\nPaint 32 light and 32 dark squares. Pick any colors you like! Here, we used purple and gold and plenty of glitter on top. For easy painting, hold them in place with long strips of double sided tape or painters tape, as in the picture. This also made sure they were no glops of paint on the sides.\nPaint the plywood base and legs. We chose black. Maybe you like orange. That's cool.", "959" ] ]

[ 10057, 9501, 10300, 5676, 10659, 11358, 9526, 361, 2576, 9128, 4973, 2786, 10137, 2106, 4204, 3984, 2358, 6540, 3752, 7808, 2635, 9596, 7561, 5440, 2997, 6459, 9521, 5456, 530, 9384, 4866, 10060, 3187, 3365, 1595, 7907, 1632, 7330, 5430, 3618, 1568, 6022, 1892, 7940, 1627, 5496, 3381, 10206, 2438, 8164, 6080, 6023, 8720, 2171, 5905, 7279, 3386, 4551, 10556, 5228, 8899, 11136, 9721, 2677, 9429, 2809, 7760, 8229, 3740, 5948 ]

[ [ "Most of this stuff comes from <PERSON>'s book: 'The Meaning of Relativity'.\nRiemann Curvature Tensor:\nImagine you take a curve, and you place a vector on one end of it. It doesn't matter which direction the vector is pointing. Now, say you displace that vector, to another point very close to it. Let's give them some names. The initial position of the vector is A and the final position is B. The vector itself is, say, $V^\\mu$. lets say the difference between the coordinates of A and B is $\\zeta$.\nNow, this process of displacing a vector is known as parallel displacement. When $V^\\mu$ reaches B, it has a change in it's direction ($\\Delta V^\\mu$). Measuring this change of direction gives us the curvature of the curve. It turns out to be $$\\Delta V^\\mu = -\\frac{1}{2} R^{\\mu}_{\\sigma \\alpha \\beta} V^\\sigma f^{\\alpha \\beta}$$ where $f^{\\alpha \\beta}$ depends on $\\zeta$. Now, the bigger tensor above, is the Riemann Curvature Tensor. This tensor completely describes the curvature of the curve.\nGeneral Relativity is a theory which describes the curvature of spacetime, so the Riemann tensor has to be necessary in the mathematics of the theory.", "418" ], [ "The problem is: $$R^{\\mu}{\\sigma \\alpha \\beta} = -\\frac{\\partial \\Gamma ^{\\mu}{\\sigma \\alpha}}{\\partial x_{\\beta}} + \\frac{\\partial \\Gamma ^{\\mu}{\\sigma \\beta}}{\\partial x{\\alpha}} + \\Gamma^{\\mu}{\\rho \\alpha}\\Gamma^{\\rho}{\\sigma \\beta} - \\Gamma^{\\mu}{\\rho\\beta} \\Gamma^{\\beta}{\\sigma\\alpha}$$\nYes. It's just too tough to calculate. Each of the $\\Gamma$s have yet more calculating to do. So it's a lot of work, with calculating each term takes you deeper down the rabbit hole; and so you could rather use:\nRicci Tensor:\nThis tensor describes the curvature of the curve, but is easier to handle than the <PERSON> tensor. So, how do you get it? First, let's talk about the Einstein Summation Convention. Basically, it is a shorthand for writing 'sum over indices'. If you have say the expression $$ds^2 = \\sum_{\\mu, \\nu} g_{\\mu \\nu} dx^{\\mu} dx^{\\nu}$$ you can simplify and write $$ds^2 = g_{\\mu \\nu} dx^{\\mu} dx^{\\nu}$$ which means that if a particular index occurs on both the top and the bottom of an expression, you 'sum over it'. So, the <PERSON> tensor is $$R_{\\mu \\nu} = R^{\\rho}_{\\mu \\rho \\beta}$$ You sum over $\\rho$ to get a more compact tensor. This is a process known as contraction Now, the <PERSON> tensor is the one actually used in the:\nEinstein Field Equations:\nWhich are $$R_{\\mu \\nu} - \\frac{1}{2}Rg_{\\mu \\nu} = 8\\pi G T_{\\mu \\nu}$$ Here $R = g_{\\mu \\nu} R^{\\mu \\nu}$ (where the <PERSON> tensor is in the contra-variant form), and I have taken $c = 1$. Now, this is the central set of equations in General Relativity. The left hand side completely describes the curvature of spacetime, caused by the energy described in the right hand side. Or, as said by the oft-quoted line\nSpacetime tells matter how to move; matter tells spacetime how to curve - <PERSON>\nBut the left hand side can be simplified. If we introduce the:\nEinstein Tensor:\nDefined as: $$G_{\\mu \\nu} := R_{\\mu \\nu} - \\frac{1}{2}Rg_{\\mu \\nu}$$ Then the field equations become: $$G_{\\mu \\nu} = 8\\pi G T_{\\mu \\nu}$$ that is another way of obtaining the Einstein Tensor $G_{\\mu \\nu}$.\nIn a nutshell:\nThe three tensors that you specified describe the curvature of space.", "818" ], [ "Components of Stress-Energy Tensor, in any arbitary coordinates, are given by, $$ T_{{\\mu}{\\nu}} = T(\\frac{\\partial}{\\partial x^{\\mu}},\\frac{\\partial}{\\partial x^{\\nu}}) .$$ One can physically interpret them as follows: $ T_{{\\mu}{\\nu}}$, at a point P of space-time, tells the flow of $\\mu ^{th} $ component of four momentum along the $\\frac{\\partial}{\\partial x^{\\nu}}$ direction. For example, $T_{00}$ denotes how much energy per unit volume is flowing in time direction, which is same as energy density. Similarly $T_{i0}$ denotes flow of momentum (not four momentum) per unit volume along time direction, that is momentum density.\nThus, $T_{ii}$ denotes flow of $i^{th}$ component of momentum along $\\frac{\\partial}{\\partial x^i}$ direction. But that's the definition of pressure. Since pressure is a local phenomenon, even in curved space-time, it does not matter whether you work in curvilinear or rectilinear coordinates. Locally every transformation is linear enough to define pressure as we usually do.\nIn your example, $(\\frac{\\partial}{\\partial r},\\frac{\\partial}{\\partial \\theta},\\frac{\\partial}{\\partial \\phi})$, at a point could be thought of constituting a Cartesian system. The radial direction could very well be defined as x direction, locally. Since pressure is also local, $T_{rr}$ denotes pressure along the radial direction.", "649" ], [ "Same goes with other two directions. $T_{\\theta \\theta}$ and $T_{\\phi \\phi}$ denotes pressure along $\\frac{\\partial}{\\partial \\theta}$ and $\\frac{\\partial}{\\partial \\phi} $ directions respectively.\nFor the second part of your question, No, you cannot do that. That would break spherical symmetry. A concise explanation is: metric and matter are coupled by Einstein Field Equation. If one is not symmetric under rotations then other cannot be symmetric.\nA detailed explanation: Assume metric is spherically symmetric and matter is given by, $$T_{\\mu\\nu}=diag(\\,\\rho(r)\\; e^{\\nu(r)},p_{r}(r)\\;e^{\\lambda(r)}, p_{\\theta}(r)\\;r^{2},p_{\\theta}(r)\\;r^{2}\\sin^{2}\\theta\\,).$$ If metric is invariant under rotation so is Einstein Tensor, $G_{\\mu \\nu}$, as Einstein Tensor is made from metric tensor. We have following equation, $$ G_{\\mu \\nu}=\\kappa T_{\\mu \\nu} .$$ The left hand side is invariant under rotation but right hand side is not. A contradiction! Therefore our assumption is wrong. Matter cannot be given by our proposed form.", "298" ], [ "The above answers seem to nicely summarize why charge is conserved in every frame of reference. I would like to take a different approach as to why that makes sense, and why the charge conservation law holds.\n1. Charge, current and conservation:\nThe most simplest way to state the conservation of charge is to say, $$\\frac{dQ}{dt} = 0$$\nThat the rate of change of charge in time is $0$, implying that the quantity of charge is a constant.\nBut, sometimes charge can decrease in a system. This does not violate the supreme principle, but rather states that charge can 'leak' or flow through an area, causing the charge in the system to decrease, and the charge outside to increase. So, the amount of charge in the entire universe is the same, but for smaller systems the above equation may not hold true.\nConsider a box with some charge inside of it. The charge can flow out through any of the faces of the box, thus decreasing the overall charge inside (it can also increase if the charges are instead entering the box). So, you need to take into account this flow of charges, called a current to make sure that the conservation law holds. The resulting mathematical form is:\n$$\\frac{d\\rho}{dt} + \\nabla . J^i = 0$$\nwhere the $\\rho$ represents the density of charge inside the box, and $J^i$ is the current vector, because current can flow through the $x$, $y$, and $z$ axes; so we use a vector to keep track of them all. What the above expression says is: the rate of change of charge in the box and the rate of change of current flowing in or out of it, is going to be conserved.\n2. Four vectors, dot products and Lorentz invariance:\nIn Relativity, we use something known as four-vectors, which are 4 dimensional vectors. Usual vectors have only three components: one corresponding to each dimension of space; in Relativity, we consider a fourth dimension: time.", "780" ], [ "So, vectors in Relativity have four components, one corresponding to time, and three to space. We denote these vectors by $$A^{\\mu}, \\mu = (0, 1, 2, 3)$$ where the $0$ index corresponds to the time component and the other three to the space components.\nNow, let's move on to Lorentz invariance. In Special relativity, whenever we want to consider events from a different reference frame, we use something known as Lorentz transformations. I am going to leave a few nice resources in the further reading below, but for now, that is enough information.\nIf a certain quantity does not change when the Lorentz transformation is applies to it, we say it is Lorentz invariant.\nSo, some of the things that are always Lorentz invariant are the dot product between two four-vectors. Again, for length purposes, I will leave a link to some resources below, but simply put, dot products between two vectors can be denoted as: $$Product_{dot} = A^\\mu B_\\mu$$\nThe only constraint is that the index of the four vectors should be the same and they should be repeated upstairs and downstairs. Expanding this expression, we get: $$A^{\\mu}B_{\\mu} = -(A^0 B_0) + (A^1 B_1) + (A^2 B_2) + (A^3 B_3)$$ which is a scalar and is Lorentz invariant. These scalars are called Lorentz scalars.\n3. Bringing it all together:\nIn Special Relativity, we denote the charge and current of a particle as a four vector $J^{\\mu}$. The time component is $\\rho$ and the space components are $J^i$. There is another four vector $\\partial_{\\mu}$ which is defined to be: $$\\partial_{\\mu} = \\left (\\frac{\\partial}{\\partial t}, \\frac{\\partial}{\\partial x}, \\frac{\\partial}{\\partial y}, \\frac{\\partial}{\\partial z}\\right)$$\nOkay. Now, particles have some properties, like mass and charge that do not change when you shift frames. Similarly for the conservation of charge, you can write it as $$\\partial_{\\mu}J^{\\mu} = 0$$ which is a dot product, so it is naturally a <PERSON> invariant.\n4. So, can charge vary for observers?\nI took an unconventional way of answering here, by first showing the true way of expressing the conservation of charge and then going through a long way to show why the law hold even when our frames change.", "418" ], [ "In General Relativity, which is our current description of gravity, changes in the gravity field is mediated by gravitational waves.\n1. What are gravitational waves:\nIf you have any medium, and you add some energy to it, it starts to oscillate or wiggle. In other words, there is sort of a disturbance in the medium. This is true for air, water and even massless fields like electromagnetic fields. These disturbances are waves.\nIn GR, gravity is described as a property of the geometry of space and time itself. Any matter or energy can change the geometry of spacetime, and this is what other objects experience as the 'gravity' of the first one.\nSpacetime is a medium in GR. It can ripple, it can be disturbed. Indeed, in situations where there is movement of energy, the spacetime around it can 'squish and squash', causing a wave of spacetime itself.\nNotice, I did not say a wave in spacetime, because the spacetime itself is waving. Space and time expand and contract. That is a gravitational wave.\n2.", "343" ], [ "What is the speed of gravitational waves:\nIf the spacetime itself is waving, then how do we define the speed of those waves?\nSimple put, we take two objects separated by a long distance and interacting through gravity. Now, if we slightly change the position of the first one, the second one will not immediately change its motion. Instead, there will be a time gap. The distance between the two objects (before and after the change doesn't matter as we only slightly changed it; also the corresponding change in movement is small).\nNow the large distance between the two objects divided by the small time gap gives us how fast gravity can propagate (through gravity waves), in other words, the speed of gravity,. That is how we define it: in terms of the distance between objects and the time gap between movement of a large object and corresponding effect on the smaller object.\n3. Trivia: What does that come out to be?\nAs it turns out the speed of light $c$. This is because of the fact that waves can be thought to have 'mass', which is basically the mass of the medium (remember that the wave is nothing but a disturbance in the medium; so the mass of the wave is the mass of the medium, in a simplistic sense).\nNow, electromagnetic fields have no mass and the wave in the fields is light. Special Relativity tells us that anything without mass travel at the speed of light, a constant $c$.\nSpace-time itself is massless too; it may contain mass in it, but that does not mean that it itself is massive too. Okay. So a wave in spacetime, is massless, and by the laws of physics, can only travel at the speed of light.\nTa-da!", "343" ], [ "Point Transformation Math Question\nI am trying to proof the classic problem to showcase Lagrangian's scalar invariant property.\nNamely, that if you have $x_i = { x_1, ...., x_n; t }$ , you can then represent $L(x_1,....,\\dot{x_1},...,t)$ and find the Euler-Lagrangian equations of motion: \\begin{equation} \\frac{d}{dt} ( \\frac{\\partial L}{\\partial \\dot{x_i}}) - \\frac{\\partial L}{\\partial x_i} = 0. \\end{equation}\nNow, if you introduce a new set of coordinates $q_j = { q_1, ...., q_n; t }$, then you too can express the equations of motion via:\n\\begin{equation} \\frac{d}{dt} ( \\frac{\\partial L}{\\partial \\dot{q_j}}) - \\frac{\\partial L}{\\partial q_j} = 0. \\end{equation} I know I have to show that indeed this is the case, thus showing $L$ is scalar invariant under point transformations.\nNow here's my problem.\nI am going to use the simplest example I know: you only have $x$ and $q$ - only one degree of freedom.\nI can define $x(q,t)$ and $q(x,t)$.\nI can find the differential as follows:\n\\begin{equation} dx = \\frac{\\partial x}{\\partial q}dq + \\frac{\\partial x}{\\partial t}dt \\end{equation}\nAnd thus, I can find $\\dot{x}$:\n\\begin{eqnarray} \\frac{dx}{dt}= \\frac{\\partial x}{\\partial q} \\frac{dq}{dt} + \\frac{\\partial x}{\\partial t} \\ \\dot{x} = \\frac{\\partial x}{\\partial q} \\dot{q} + \\frac{\\partial x}{\\partial t} \\end{eqnarray}\nI have read that you can turn that last equation into: \\begin{equation} \\frac{\\partial \\dot{x}}{\\partial \\dot{q}}= \\frac{\\partial x}{\\partial q} + \\frac{\\partial}{\\partial q}\\frac{\\partial x}{\\partial t} \\ \\end{equation}\nwhich would yield: \\begin{equation} \\frac{\\partial \\dot{x}}{\\partial \\dot{q}}= \\frac{\\partial x}{\\partial q} \\end{equation}\nHere's my question:\nI am not sure how to justify the change that yield this result. Because if I follow the equation closely, I would find this value: \\begin{equation} \\frac{\\frac{dx}{dt}}{\\frac{dq}{dt}} = \\frac{\\partial x}{\\partial q} + \\frac{d}{dq}\\frac{\\partial x}{\\partial t} \\end{equation}\nWhat I am missing or doing wrong that yields the intended result in partials rather than the result I just wrote above?", "101" ], [ "Derivative of a Wilson Line\nIt's my first post on this website so please excuse any breaches of protocol that I'm unaware of.\nI've come across a formula for taking derivatives of Wilson Lines with respect to points on the path, but I'm having trouble deriving it. I found it in Equation 12 of https://arxiv.org/pdf/1210.2581.pdf , where it is presented without proof or citation. I therefore expect that it is an elementary proof that is very familiar to people. My attempt to prove it goes as follows:\n$W(x,y) \\equiv \\hat{P} \\exp[ig\\int A_\\mu(s) d s^\\mu] $\nDefines the path ordered <PERSON> line with starting point $y^\\mu$ and endpoint $x^\\mu$. Given a particular field $A_\\mu$ I think of this as a functional of the path. Instead, if we can parametrize the path via $s^\\mu(t)$, then the <PERSON> line can instead be though of a function of the endpoints:\n$W(x,y) = \\hat{P} \\exp[ig\\int_{t_y}^{t_x} A_\\mu(s(t))\\frac{ ds^\\mu}{dt} dt]$\nWhere we've implied $s^\\mu(t_y) = y^\\mu$ and $s^\\mu(t_x) = x^\\mu$. I would like to get $\\frac{\\partial W(x,y)}{\\partial x^\\mu}$, but I only have $t_x$ as an accessible variable in the expression.", "818" ], [ "So then I take $\\frac{ \\partial W(x,y)}{\\partial t_x}$ instead:\n$\\frac{ \\partial W(x,y)}{\\partial t_x} = igA_\\mu(x) \\frac{ ds^\\mu}{d t}|_{t=t_x}W(x,y) $\nThen I think to myself that since $x^\\mu$ is a function of $t_x$, maybe I can invert the function and use the chain rule:\n$\\frac{ d}{dx^\\mu} =^? \\frac{dt_x}{dx^\\mu}\\frac{d}{dt_x}$\n(By this logic, it should really be $\\frac{\\partial t_x}{\\partial x^\\mu}$, but I'm thinking we can write $\\frac{ d t_x}{d x^\\mu} = (\\frac{ d x^\\mu}{d t_x})^{-1}$). Then, this $\\frac{dt_x}{d x^\\mu}$ looks like it will cancel the $\\frac{ ds^\\mu}{dt}|_{t=t_x}$ in the above expression since $s^\\mu(t_x) = x^\\mu$. So I write\n$\\frac{ \\partial W(x,y)}{\\partial x^\\mu} = igA_\\mu(x) W(x,y).$\nNote that if I took the derivative with respect to the start point $y^\\mu$ instead, I would get a similar result but with an extra minus sign from the fundamental theorem of calculus:\n$\\frac{ \\partial W(x,y)}{\\partial y^\\mu} = -ig W(x,y) A_\\mu(y).$\n(Throughout I have assumed that the chain rule maintains the ordering) Then, if I want to extend this to taking derivatives with respect to any point on the path, not just an endpoint, I can use the fact that:\n$W(x,y) = W(x,z)W(z,y)$\nStraightforward application of the product rule and our above expressions then gives:\n$\\frac{ \\partial W(x,y)}{\\partial z^\\mu} = 0.$\nWhich seems obvious because we've only allowed $z^\\mu$ to move along the pre-specified path for the <PERSON> line. So the <PERSON> line itself does not change. The only way to get a nonzero derivative is to use the start point or the endpoint, because changing them changes the length of the entire path. However, in my understanding, this is actually incorrect. The result is not zero! Equation 12 of https://arxiv.org/pdf/1210.2581.", "818" ], [ "Well... $A^\\mu$ is not really a tensor. The tensor form of that 4-potential is\n$$ A = A^\\mu \\partial_\\mu,\\ A^\\mu \\in \\mathbb{R} $$\nSo since you know that $\\partial_\\mu$ transform as a tensor, then $A$ is a tensor and you say that its components transform as a tensor. Let me explain this a little bit more:\nLet's say I want to change coordinates $x \\rightarrow y$, then\n$$ \\partial_\\mu = \\frac{\\partial}{\\partial x^\\mu} \\rightarrow \\partial_\\mu^{\\ '} = \\frac{\\partial y^\\nu}{\\partial x^\\mu}\\frac{\\partial}{\\partial y^\\nu} $$\nTherefore, since $A^\\mu$ is just a function, under this change\n$$ A(x) = A^\\mu(x)\\partial_\\mu \\rightarrow A^{'}(y) = A^{'\\ \\mu}(y)\\frac{\\partial y^\\nu}{\\partial x^\\mu}\\frac{\\partial}{\\partial y^\\nu}, \\quad A^{' \\mu}(y) = A^\\mu(x(y)) $$\nAnd now you can make an abuse of language and say that $A^\\mu$ is a tensor because it transforms as\n$$ A^\\mu(x) \\rightarrow A^{'\\ \\mu}(y)\\frac{\\partial y^\\nu}{\\partial x^\\mu} $$\nNow, how do you know that $A^\\mu = (\\phi , \\vec{A})$ gives you the correct theory? As far as I know, that is due to a special relativity extension of classical lagrangian mechanincs.", "818" ], [ "Classically you have that the interaction is given as\n$$ S_{int} = \\int dt\\ L_{int} = -\\int dt\\ \\phi $$\nSince $S$, the action, must be invariant under <PERSON> tranformation you suggest that $\\phi$ is the zero-th component of some 4-vector $A^\\mu = (\\phi, \\vec{0})$ so now you can write\n$$ S_{int} = -\\int dt\\ A^0 = -\\int dx_0\\ A^0 $$\nBut this is not a Lorentz scalar, so you extend $A^\\mu = (\\phi, \\vec{A})$ but without assuming that $\\vec{A}$ is the usual magnetic vector potential. Therefore,\n$$ S_{int} = -\\int dt\\ A^0 \\xrightarrow{extension} -\\int dx_\\mu\\ A^\\mu = -\\int dt\\ \\frac{dx_\\mu}{dt}A^\\mu\n\\tag1$$\nThis is now a Lorent scalar (so invariant) since the index $\\mu$ is dummy now. Let's see what $\\vec{A}$ is by developing Eq. (1) (recall $x_0 = dt$):\n$$ S_{int} = -\\int dt\\ \\phi(dt/dt) - \\vec{A}(d\\vec{x}/dt) $$\nThe part on $\\vec{A}$ is the usual interaction of the form current times magnetic potential if consider $\\vec{A}$ like that and goes to lagrangian density formulation. By construction $A^\\mu$ must be a 4-vector (tensor of rank 1) because if it wasn't that, $A^\\mu dx_\\mu$ wouldn't be a <PERSON> scalar", "418" ], [ "Integrating the geodesic equation to obtain Newtonian energy of test particle\nI am studying General Relativity, and have come across a question that I am finding rather intractable:\nIn Newtonian Theory, the energy equation for a test particle in orbit around a point mass is: $$\\frac{v^{2}}{2} + \\frac{\\ell^{2}}{2r^{2}} - \\frac{GM}{r} = \\mathcal{E}$$ Where $r$ is the radius, $v$ is the radial velocity, $\\ell$ is the angular momentum per unit mass, $\\mathcal{E}$ is the constant energy per unit mass and $-GM/r$ is the gravitational potential. For the <PERSON> solution show that the integrated geodesic equation may also be written in the form: $$\\frac{v_{s}^{2}}{2} + \\frac{\\ell_{s}^{2}}{2r^{2}} + \\Phi_{s}(r) = \\mathcal{E}{s}$$ Where $v{s} = \\mathrm{d}r/\\mathrm{d}\\tau$, and $\\ell_{s}$ and $\\mathcal{E}_{s}$ are constants.\nI am not really sure what it means by integrating the geodesic equation. My understading is that the geodesic equation is given by:\n$$\\frac{\\mathrm{d}^{2} x^{\\lambda}}{\\mathrm{d} \\tau^{2}} + \\Gamma^{\\lambda}_{\\mu\\nu}\\frac{\\mathrm{d} x^{\\mu}}{\\mathrm{d} \\tau}\\frac{\\mathrm{d} x^{\\nu}}{\\mathrm{d} \\tau} = 0$$\nWhere $\\Gamma^{\\lambda}_{\\mu\\nu}$ is the affine connection. However, this leads to a system of equations, none of which, when integrated, yield the form given in the question.\nI'm sure that I am missing something fundamental and simple, but I just cannot find it in any of the references or materials that I have been given.\nI thought that perhaps integrating the geodesic equation directly would be the way to go, but I do not end up with the correct solution:\n$$\\int\\left(\\frac{\\mathrm{d}^{2} x^{\\lambda}}{\\mathrm{d} \\tau^{2}} + \\Gamma^{\\lambda}{\\mu\\nu}\\frac{\\mathrm{d} x^{\\mu}}{\\mathrm{d} \\tau}\\frac{\\mathrm{d} x^{\\nu}}{\\mathrm{d} \\tau}\\right)\\:\\mathrm{d}\\tau = \\mathcal{E}{s}$$\nWe note that as integration is distributive over addition, we find:\n$$\\frac{\\mathrm{d}x^{\\lambda}}{\\mathrm{d}\\tau} + \\int\\left(\\Gamma^{\\lambda}{\\mu\\nu}\\frac{\\mathrm{d} x^{\\mu}}{\\mathrm{d} \\tau}\\frac{\\mathrm{d} x^{\\nu}}{\\mathrm{d} \\tau}\\right)\\:\\mathrm{d}\\tau = \\mathcal{E}{s}$$\nWe note that if we let $\\lambda = r$, then this becomes proportional to $v_{s}$ and thus I am missing a factor of $v_{s}$.\nEdit 2: After the very helpful comments below, I went back and did the question again, this time getting stuck at a different point.\nSo we find that in the $\\lambda = t$ case, the only <PERSON> symbols $\\Gamma_{\\mu\\nu}^{t}$ that are non-zero are when $\\mu = t$, $\\nu = r$ or vice versa.", "394" ] ]

[ 2815, 11421, 9453, 1942, 4913, 11336, 4288, 6658, 4201, 7577, 10847, 494, 2976, 6285, 4108, 8948, 10066, 6533, 3726, 2519, 7032, 4281, 8870, 5178, 2196, 10682, 4049, 1139, 5828, 1795, 8036, 6759, 6848, 686, 2882, 9196, 4688, 9250, 315, 191, 5384, 4955, 9555, 1109, 8777, 760, 8546, 1337, 6937, 2357, 6352, 924, 141, 11382, 2115, 1282, 1198, 7947, 7301, 1512, 4776, 10997, 3046, 4182, 3617, 6257, 8341, 1418, 10821, 2024 ]

[ [ "I changed your model solution a little bit; but it's like <PERSON> wrote in his answer: you redefined xi and yi in the process, so when you later on define the netCDF values for lat and lon you try to fill small 1D arrays with a 2D array. That is the source of your error.\n```python import numpy as np from scipy.interpolate import griddata import xarray as xr import pandas as pd import rioxarray import netCDF4 as nc4 import matplotlib.pyplot as plt from shapely.geometry import Point import geopandas as gpd from pyproj import CRS\nCRS_3857 = CRS.from_epsg(3857) CRS_wkt = CRS_3857.to_wkt(pretty=False) print(CRS_wkt)\n--- Input data....\nlat = [50.1, 50.2, 50.3, 50.4, 50.5, 62] lon = [ 8.1, 8.2, 8.3, 8.4, 8.5, 12] temp = [1 , 2 , 3 , 4 , 5 , 6]\nPut into pandas Dataframe\ndf = pd.DataFrame( { 'latitude': lat, 'longitude': lon, 'temp': temp } )\nPrepare geometry\npointShp = [Point(x, y) for x, y in zip(df.longitude, df.latitude)] pointGpd = gpd.GeoDataFrame(df, geometry=pointShp, crs='EPSG:4326')\nReproject\npoint3857 = pointGpd.to_crs('EPSG:3857') point3857['x'] = point3857.apply(lambda x: x.geometry.centroid.x, axis=1) point3857['y'] = point3857.apply(lambda x: x.geometry.centroid.y, axis=1) df = point3857[['x','y','temp']] lon = list(df['x']) lat = list(df['y']) temp = list(df['temp'])\nProceed with your source code\n--- Project input data on a regular grid\nxi = np.linspace(min(lon), max(lon), 500) yi = np.linspace(min(lat), max(lat), 500) xi, yi = np.meshgrid(xi, yi) zi = np.ones_like(xi,dtype=np.float32) * np.NaN\nzi = griddata((lon, lat), temp, (xi, yi), method='linear')\nfor i in range(len(temp)): idx = np.argmin( np.sqrt( (xi-lon[i])2 + (yi-lat[i])2) ) zi[np.unravel_index(idx, xi.shape)] = temp[i]\n--- Check... => LOOKS GOOD\nplt.figure(figsize=(15,7)) plt.subplot(1,2,1) plt.scatter(lon, lat, temp, temp) plt.subplot(1,2,2) plt.pcolor(xi, yi, np.where(np.isnan(zi),0,zi)) plt.show()\n--- Open NetCDF file to write on\nwith nc4.Dataset('test.nc', 'w' , format='NETCDF3_CLASSIC') as ds: # --- Initialize the dimensions of the dataset dim_time = ds.createDimension('time', 0) dim_lat = ds.createDimension('lat', yi.shape[0]) dim_lon = ds.createDimension('lon', xi.shape1)\n# --- Create the corresponding variables for the dimensions\ntime = ds.createVariable('time', np.float32, 'time')\nlatitude = ds.createVariable('lat', np.float32, 'lat')\nlatitude.units = ['degrees north']\nlatitude.axis = ['Y']\nlatitude.standard_name = ['latitude']\nlongitude = ds.createVariable('lon', np.float32, 'lon')\nlongitude.units = ['degrees east']\nlongitude.axis = ['X']\nlongitude.standard_name = ['longitude']\n# --- Fill with 1D (!", "509" ], [ "In general, the relation between the three datasets is as follows: - The simulation model is initiated with a set of boundary and initial conditions, and will on the long-term provide good mean conditions. However, depending on the frequency of data assimilation, the results on short-term time spans can deviate from the observations, due to internal variability of the model. Besides, models aren't perfect and sometimes have biases for some variables. - In contrast, the satellite data provides observations. These are of course limited by technical aspects, but as indicated by the table in Section 3 of the link you provided, the quality of the precipitation measurements is very good. However, satellites often have a poorer temporal/spatial resolution than models (a satellite can't be everywhere at once and depending on the type, cannot measure at a very high resolution). - The reanalysis is a combination of the model simulation and the observations, where both sets are merged (via data assimilation) to provide a coherent dataset. This provides a dataset that can be considered 'pseudo-observations' (they are often used as continental-scale or global scale 'observation' datasets in climate studies), but without the poor spatial/temporal resolution of satellite observations. The biases in the reanalyses should be lower than in the original weather simulation, but may still be present.\nConcerning the difference between temperature and precipitation: temperature is much easier to correctly simulate than precipitation (e.g. because of the dry/wet-day transition).", "867" ], [ "As such, on a monthly scale, precipitation biases might be already quite large. For more information on precipitation biases, this paper might be relevant: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010jd014532 (<PERSON> et al. (2010): The dreary state of precipitation in global models)\nIn essence, the dataset you want to use should depend on your needs. If spatial/temporal coverage and historical data is the most important, the reanalysis is probably your best choice. If you want to know more about this dataset and its biases, this article is a good starting point: https://hess.copernicus.org/articles/24/2527/2020/ (<PERSON> et al. (2020): Evaluation of the ERA5 reanalysis as a potential reference dataset for hydrological modelling over North America). Or, if your goal is impact assessment, you might immediately check this one: https://essd.copernicus.org/articles/12/2097/2020/ (<PERSON><PHONE_NUMBER>/ (Tarek et al. (2020): Evaluation of the ERA5 reanalysis as a potential reference dataset for hydrological modelling over North America). Or, if your goal is impact assessment, you might immediately check this one: https://essd.copernicus.org/articles/<PHONE_NUMBER>/ (Cucchi et al. (2020): WFDE5: bias-adjusted ERA5 reanalysis data for impact studies)", "867" ], [ "Typically your sampled fluid velocity data would 'live' on a specific element of the mesh. For example in 3D, the velocity field 'lives' on the faces of your volume mesh. They are scalar values on faces representing the flux of fluid through that face.\nThis is a good explanation of how you calculate differential quantities on the discrete mesh. http://www.geometry.caltech.edu/pubs/ETKSD07.pdf\nThe flux on a mesh is a 2-form and the gradient of that would be a 3-form, meaning it lives on cells of the mesh. In data it would be 3 numbers stored at the cells representing difference in flux in the x direction, y dir, and z dir. The gradient operator on the mesh is literally a difference flux1-flux2. So your numbers at a cell become [flux(x+)-flux(x-), flux(y+)-flux(y-), flux(z+)-flux(z-)]. I assume you're on a regular cube mesh... If not, then everything is a little different... This is an implicit representation of gradient of u.", "432" ], [ "Which is a diagonal matrix in the basis representing the orientation of the cell.\nPresumably your pressure data also lives on cells of the mesh so you can simply multiply by the identity and add them to your grad(u)+grad(u)T. Your result in data would be a 3x3 matrix at each cell of the mesh.\nThis is an implicit representation of your stress tensor. I believe the resulting diagonal matrix will represent stresses in the orientation of the cell. The choice of discretizing velocity as fluxes forces your stress matrix to be diagonal. You can rotate the basis of the stress tensor to something else, if needed, then it won't necessarily be diagonal.\nIf for some reason the data you recorded for velocity doesn't 'live' on faces, that's still ok. You can do an additional step to convert from wherever your data lives to the faces. For example, if you chose to represent velocity data as (x,y,z) vectors at the cells of the mesh, you can integrate the implied velocity field across the faces, resulting in the flux representation of your velocity field. You would need an interpolation scheme to do the integration, like HBR said. But a super simple method could just be to take the difference between the component of your (x,y,z) velocity in the direction of the cell face, with the component of the (x,y,z) velocity on the other side of the cell face. This is clearly not a smooth interpolation though. There's lots of interpolation schemes.", "7" ], [ "SciPy odeint giving different results with matrix multiplication\nI've asked this at stackoverflow but maybe this community will have a better idea of the answer.\nI'm currently trying to develop a function that performs matrix multiplication while expanding a differential equation with odeint in Python and am seeing strange results.\nI have the below matrix of values and function that takes specific values of that matrix: ``` from scipy.integrate import odeint x0_train = [2,0] dt = 0.01 t = np.arange(0, 1000, dt) matrix_a = np.array([-0.09999975, 1.999999, -1.999999, -0.09999974])\nFunction to run odeint with\ndef f(x, t, a): return [ a[0] * x[0] + a[1] * x[1], a[2] * x[0] - a[3] * x[1] ] odeint(f, x0_train, t, args=(matrix_a,))\narray([[ 2. , 0. ], [ 1.99760115, -0.<PHONE_NUMBER>], [ 1.99440529, -0.07997867], ..., <PHONE_NUMBER>, 1.15608741], [ 1.71199436, 1.12319701], [ 1.73240339, 1.<PHONE_NUMBER>]]) ```\nThis seems right, but when I create my own function to perform multiplication/regression, I see the results at the bottom of the array are completely different. I have two sparse arrays that provide the same conditions as matrix_a but with zeros around them.\n``` from sklearn.preprocessing import PolynomialFeatures new_matrix_a = array([[ 0. , -0.09999975, 1.999999 , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0.", "509" ], [ "], [ 0. , -1.999999 , -0.09999974, 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. , 0. ]])\nNew function\ndef f_new(x, t, parameters): polynomials = PolynomialFeatures(degree=5) x = np.array(x).reshape(-1,2) #x0_train_array_reshape = x0_train_array.reshape(1,2) polynomial_transform = polynomials.fit(x) polynomial_features = polynomial_transform.fit_transform(x).T x_ode = np.matmul(parameters[0],polynomial_features) y_ode = np.matmul(parameters1,polynomial_features) return np.concatenate((x_ode, y_ode), axis=None).tolist()\nodeint(f_new, x0_train, t, args=(new_matrix_a,))\narray([[ 2.00000000e+00, 0.00000000e+00], [ 1.99760142e+00, -3.99573216e-02], [ 1.99440742e+00, -7.98188169e-02], ..., [-3.50784051e-21, -9.99729456e-22], [-3.50782881e-21, -9.99726119e-22], [-3.50781711e-21, -9.99722781e-22]]) `` As you can see, I'm getting completely different values at the end of the array. I've been running through my code and can't seem to find a reason why they would be different. Does anybody have a clear reason why or if I'm doing something wrong with myf_new? Ideally, I'd like to develop a function that can take any values in thatmatrix_a`, which is why I'm trying to create this new function.\nThanks in advance.", "509" ], [ "The issue is not 100% clear. I am assuming part of the problem is that you have many areas of the same land cover type in the same subcatchment, but different parts of this cover type need to irrigated by different reservoirs.\nIf this is the issue, one approach could be to set up your model with different land cover type codes for the different areas that are irrigated from different reservoirs. For example, if your initial land cover map has areas mapped as wheat fields, but you know which fields are specifically irrigated from three different reservoirs, you could make a land cover map that has wheat01, wheat02, and wheat03 as different \"cover classes\", despite them all actually being wheat. This will mean they will be different HRU types in your model set up.\nTo bring this into SWAT+: each of these areas would need a different grid code number in the land cover input raster, you would need to make a differently named entry for each one in the 'plant' parameter table, and then your land cover lookup table would need to link each to these different entries in the plant parameter table. In this example, if its all wheat, and you are happy with the default wheat parameters in SWAT+, you can just copy the wheat parameter row and paste it three times at the end of the table and give these new names and codes like wheat01, wheat02, wheat03.\nA hitch in this approach could come in automated calibration, if you are doing that.", "964" ], [ "In this process, each wheat cover \"subtype\" (wheat01, wheat02, wheat03 for the areas irrigated by reservoirs 1,2,&3) would be treated as if it was an independent cover type. This means their parameter values may be changed in different ways to one another in calibration, whereas you probably want their vegetation parameters to be consistent across the three as they are all wheat... This may take some manual calibration intervention to resolve - i.e. setting the wheat01,wheat02,wheat03 parameters to be the same in the end.\nAlso if you have many many reservoirs, there is still work to be done on linking each HRU to the right reservoir. Doing this in the text files rather than the SWAT+ Editor interface would likely faster and you could automate the process using an R or Python code. If you modify the text files outside of the Editor interface you cannot \"write tables\" in the Editor before running the model (if you run it from the Editor) because this will actually undo the changes you've made.", "964" ], [ "solve_ivp - Overflow encountered in double_scalars\nI'm modeling an electron that orbits the nucleus. Of course, charged particles radiate away there energy so it'll crash into the nucleus. My approach has been to to evaluate the coulomb force and add the reaction force (given by the <PERSON>-Lorentz formula). The equation of motion would be\n$F = ma = \\frac{1}{r^2} - \\beta\\dot{a}$\nwhere $\\beta = \\frac{2}{3c^3}$ in my units, and m =1. Rearranging this the def eq to solve is\n$F = \\dot{a} = (\\frac{1}{r^2} - a) \\frac{1}{\\beta}$\nand I multiply by $\\frac{x}{r}$ or $\\frac{y}{r}$ to get the x or y directions respectively.", "394" ], [ "The implementation is below\n``` import numpy as np from scipy.integrate import odeint, solve_ivp import matplotlib.pyplot as plt\nc = 137.0 B = ((3.0c*3)/2.0)\ndef func(t, o): # [0x, 1y, 2vx, 3vy, 4ax, 5ay] r = np.hypot(o[0], o1) dodt = [o[2], o[3], o[4], o[5], Bo[0](-(1/r3.0) - o[4]/r), Bo1(-(1/r3.0) - o[5]/r)] return dodt\ninitial = [br, 0.0, 0.0, 1.0, -1.0, 0.0] # [x, y, vx, vy, ax, ay] span = [0.0, 10.0] time = np.linspace(span[0], span1, 10000)\n%% Solve differential equation\nsol = solve_ivp(fun=func, t_span=span, t_eval=time, y0=initial, dense_output=True, max_step=0.05).sol xe, ye, xve, yve, axe, aye = sol(time)\nprint(xe[-1], ye[-1])\n%% Plot states\nplt.plot(xe, ye) plt.plot(xe[-1], ye[-1], 'ro') plt.plot(xe[0], ye[0], 'yo') axx = plt.gca() axx.set_aspect('equal') plt.show() `` I was using odeint before and got the error messageExcess work done on this call` which from this post I know can be solved using a solver that can handle events, however it seems that these events only terminate the solver before it breaks, but I want it to continue as it shouldn't break to begin with if that makes any sense. Using odeint I get the following plot\nAt least it finishes at the origin which it's what it's supposed to do, but it should go around it a few times first. I guess my question is evident, how can I solve the ode without it breaking? Thanks in advanced.\nEdit: I have found the problem (I think). When we get close to the center 1/r^3 becomes too large and breaks everything. However I would like this to go all the way, how do I get around this issue?", "509" ], [ "Extremas and saddle point of 3D field at different scales\nI have a scalar 3D field $f(x, y, z)$ with $x,y,z$ on a regular grid. I would like to know the location of the maximas, minimas, saddle point and their relation as a function of a smoothing scale.\nFor that, I'm convolving my field $f$ with a filtering function that is a Gaussian with a variance $\\sigma$. I vary $\\sigma$ from 0 to the size of my grid. I want to be able to:\n1. track the location of extremas and saddle point as a function of $\\sigma$\n2. locate the merging events between two saddle points / a saddle point and an extremum\n3. be able to tell which saddle point / extremum merged into which\nAn extremum / saddle point is defined as $$ \\nabla f = 0 $$ Extremas are distinguished using the Hessian: $$ H_{i,j} = \\nabla_i\\nabla_jf = \\mathrm{diag}(e_1, e_2, e_3)$$ where $e_1, e_2, e_3$ are the eigenvalues of the Hessian. If all of them are negative (resp.", "281" ], [ "positive), the point is a maximum (resp. minimum). If one and only one is positive (resp. negative), the point is a saddle point which is a maximum (resp. minimum) in 2 dimensions.\nRidges are defined as curves on which $$ \\nabla f = \\mathrm{diag}(0,e_1,e_2)$$ where $e_1, e_2 \\neq 0$.\nFor now, I am finding the location of the extremas and saddle point by doing a quadratic interpolation $P(x,y,z)$ on each point of my grid and by computing its first and second derivatives. However I have two issues:\n1. each time I smooth at a different scale, I don't use the information about the location of the extremas and saddle point at the previous scale\n2. I don't know how to robustly find which extrema is linked to which saddle point, and hence, I can't tell robustly which point is merging into which.\nDo you have any advice about this problem?\nNB: it has to be fast enough to be able to run in less than a month on a 100x100x100 grid, at ~100 smoothing scale for 100,000 grids.", "835" ], [ "Assuming $B$ is not angle-dependent, you know the coefficients of each $f_i$ a priori, and $\\mathbf{f}$ can only be evaluated by summing up the spherical harmonics expansion, simplify your problem by making use of the orthogonality of spherical harmonics instead of numerically integrating.\nLet $f_i(\\theta,\\phi)=\\sum_{lm}f_{i,lm}Y_l^m(\\theta,\\phi)$. Then your cost function becomes, using the summation convention: $$ \\begin{align} g &= \\int d\\Omega f_{i,lm}^Y_l^{m}(\\theta,\\phi) (B_{ji}^ + B_{ij})f_{j,l'm'}Y_{l'}^{m'}(\\theta,\\phi)\\ &= f_{i,lm}^f_{j,l'm'}(B_{ji}^ + B_{ij}) \\int d\\Omega Y_l^{m}(\\theta,\\phi) Y_{l'}^{m'}(\\theta,\\phi)\\ &= f_{i,lm}^f_{j,l'm'}(B_{ji}^ + B_{ij}) \\delta_{ll',mm'}\\ &= f_{i,lm}^f_{j,lm}(B_{ji}^ + B_{ij}) \\end{align} $$ Assuming $F_{lm}=(f_{1,lm},\\ldots,f_{n,lm})$, this can be written as $$ g=\\sum_{lm} F_{lm}^\\dagger (B^\\dagger+B) F_{lm}. $$ We see that for each scalar element of the sum $F_{lm}^\\dagger B^\\dagger F_{lm}=(F_{lm}^\\dagger B F_{lm})^\\dagger$, so we can simplify further to $$ g=2\\mathfrak{R}\\sum_{lm} F_{lm}^\\dagger Q L^{-1} F_{lm}. $$ Since you only have control over the elements of $Q$, you can precompute and store as a vector $x_{lm}=L^{-1}F_{lm}$s.", "804" ], [ "Now, you know the $F_{lm}$ and $x_{lm}$ coefficients, and $Q$ is by definition orthogonal. One way to make the sum large is to make $Q$ span the space of the \"largest\" $F_{lm},x_{lm}$. You could take the $k \\leq n$ largest-norm $F_{lm}$ and $x_{lm}$ vectors, put them in a matrix (horzcat in Matlab), take the SVD, and use its column space matrix as your $Q$.\nA similar approach can be easily derived in the case that $\\mathbf{f}$ is cheap to evaluate (i.e., with fewer than $\\mathcal{O}(L^2)$ operations per quadrature point, where $L$ is the maximal degree of spherical harmonics used), with samples of $\\Omega$ taking the place of the $l,m$ indices. I realize that taking the real part in the above expression may change your approach slightly; have not yet thought that through completely.", "976" ] ]

[ 7666, 8189, 3560, 1022, 8916, 11385, 10892, 3428, 5201, 8729, 554, 5392, 10832, 9117, 52, 4778, 6282, 9475, 7549, 1930, 8307, 1387, 9010, 4087, 5818, 7608, 1061, 449, 10133, 710, 697, 4192, 1557, 9467, 2429, 9016, 4633, 2085, 4715, 9635, 2886, 9108, 5640, 6377, 2798, 4253, 1890, 5096, 5479, 5429, 9192, 11425, 9924, 11097, 10477, 2006, 7359, 3928, 5083, 10205, 7617, 5498, 8087, 7041, 10809, 6146, 8980, 9826, 10611, 9486 ]

[ [ "Could a 19th century setting support purely mechanical orbital satellite and manned orbital launches?\nIn my setting, military innovation spurred by the American Civil War (1861-1865) prompts the design and construction of counterweight-driven skyhooks for the delivery of suborbital long-range munitions.\nThe devices, nicknamed \"Tennessee Slingshots,\" are used to bombard Charleston and Vicksburg with barrages of small bombs with parabolic transatmospheric trajectories. The bombs are poorly aimed, and don't ultimately contribute in any significant military way to the more focused destruction wrought by heavy mortars and traditional artillery.", "922" ], [ "But the relatively modestly-sized Tennessee Slingshots excite scientific and engineering interest in the possibilities of space exploration, given that the objects launched by these skyhooks are the first man-made artifacts to exit the lower reaches of the Earth's atmosphere.\nAfter the war, continued engineering improvements lead to a decision to invest in a massive public works project - a huge space city that takes advantage of the rugged terrain of Mexico's Barrancas del Cobre. The fact that this canyon system in the western Sierra Madres is relatively close to the equator means that it's possible to take advantage of the Earth's rotational momentum, and the depth of the canyon means that the height differential allows for the construction of a number of experimental counterweight-driven skyhooks of larger and larger size.\nUltimately, a great chunk of mountain is excavated and fashioned into a massive half-million-ton counterweight on angled tracks, tethered by massive iron cables to elaborate transmission-works that translate the mechanical movement of the counterweights into the the supersonic movement of a tracked launch assembly that runs up the side of a mountain and continues on a slender rail supported by towers high into the air.\nThe gear ratio is such that as the counterweight slides three or four miles down a steep slide into a water pool, a looped cable is accelerated along a twenty-mile track until an object carried in a sled on the track is traveling fast enough to achieve escape velocity.\nUpon reelection (following the intervening term of his rival <PERSON>), <PERSON> announces at his inaugural address that he will authorize funds and support the goal of the Mexican-American Aeronautic Corporation to safely launch a man into orbit and retrieve that aeronaut by the end of the decade.\nIs this effort doomed to fail? Could late-19th century engineers have successfully built such a skyhook, or are the available materials and technology not up to the task? Would massive iron chains snap like taffy under the strain, or would friction cause the whole building-sized gear assembly to melt and disintegrate? I'm trying to conceive of a mechanical orbital delivery system that would not rely on concussive chemical acceleration - the lead engineer would at least be aware that you can't shoot people out of a cannon - hence the long acceleration track and geared transmission. And I want to limit myself more-or-less scrupulously to the industrial and scientific capacity of the 1880s, without resort to hand-waving, anachronistic developments, or pure balonium.", "302" ], [ "19th century British moon landing\nIn the aftermath of the <PERSON> doctrine, the British empire decided to expand heavenward. As the nobles, captains, empiricists, electricians, and mechanics explained to the Majesty, technological advances now opened the way to new heights of colonization (literally). For example: - The first manned flight of a balloon in America occurred January 9, 1793 - Diving apparatuses had been in use for centuries, and by 1836, proto-standardized diving suits were successfully being used to recover undersea wreckage - By 1856, commercial methods for refining pure aluminum existed - The first commercially successful internal combustion engine was created by <PERSON> around 1860 - Solid fuel rockets were already being used in warfare, notably the war of 1812 and the Napoleanic wars ... Accuracy greatly improved in 1844 when <PERSON> modified the rocket design so that thrust was slightly vectored - <PERSON> began to construct a small difference engine in c. 1819 and had completed it by 1822 - The first wireless telephone conversation occurred in 1880, when <PERSON> and <PERSON> invented the photophone, a telephone that sent audio over a beam of light.\nDrawing on these advances, the Crown's personal backing, and 49 years of hard R&D (spanning 1850-1899), the British rocketeers developed 5 Shooting Stars: massive rockets capable of landing 1000 kg each on the moon. As efficient liquid fuel engines were yet to be developed, the boosters employed gunpowder-based engines which were 'gimbaled' by sliding inhibitory rods between fuel pellets to tune their reaction rates -- not too differently than would be employed in nuclear reactors decades later. Inefficient hydrogen-oxygen combustion thrusters performed finer correction maneuvers.", "308" ], [ "The entire ascent sequence and translunar orbit injection was governed by a collection of clocks, tabulating machines, and tilt-sensitive governers. However, since it would be until 1935 that radar was discovered, humans were needed to pilot the lander stage -- there was no room for unmanned tests.\nThe Shooting Stars were quite heavy in comparison to modern rockets: with an exhaust velocity of only 800 m/s, the overall launch vehicle weighed in on the order of billions of pounds and thus required a mass ratio in the 10000's. To compensate, all 5 Shooting Stars were launched within a few hours of each other, and landed within a 100 yard neighborhood on the surface of the moon. While each of the landers carried some fuel needed for the return ascent, only one was specially equipped with the balloons, air-tanks, and food that would be needed for the return journey and reentry.\nThe launch day finally came on December 1st, 1899. Rushing to launch what they had yet produced in time for the turn of the century, all 5 Shooting Stars took off from the Port of London. Most ended in disaster: the first rocket's gunpowder fuel pellets had inhomogeneities that caused an explosion early in takeoff; the third rocket made it through ascent, but had a compressed gas leak that irreversibly steered it off course until the captain noticed it too late, thankfully, this was the space-vessel with reentry and landing equipment, so it simply reentered and landed in Fiji, where the captain started a cargo cult after himself; residual turbulence fields from rockets 3 and 4 steered rocket 5 off-course, ultimately crashing in Berlin and triggering an early World War I; rockets 2 and 4 successfully landed on the moon, but as the ascent lander never made it, all they could do was photophone their feat home and ask for help. Given the new war on their hands, Britain was not able to help.\nSticking to hard science, could such an alternate history of space exploration be possible?", "99" ], [ "Do my colonists stand a chance? A world of super-materials\nWhen the first explorers returned from the New World, it was with terror in their eyes. Violent shores, a jungle with trees taller than hills, and unspeakable monsters behind every towering frond - they begged that all of Europe be warned of this verdant hell so that never again would a man die the ignoble death of an insect. Unfortunately, they had not returned empty handed.\n\"Magnified Materials,\" it was quickly discovered that even the beach sand of the Americas possessed strength in excess of anything known to man. From this, a simple and enduring theory was formulated, with consequences that would change the world.\nTheory of Magnified Materials:\nAll substances native to the Americas behave such that if one were to become a giant on arrival, they would perceive the New World to be no different than the one they had came from; a desiccated American leaf will catch less air and not deform under its weight like a blanket of European leaves might, yet once ignited, its great mass will burn in the same time as its smaller cousin. Later on, it would be discovered that the rapidity with which a magnified mass falls depends on what changed its motion - being greater for the giant indigenous and lesser for anyone else.", "302" ], [ "This agrees with the observation that magnified materials are no more dense, and possesses no greater inertia than equivalent materials found in the Old World. In effect, it is as if the colonists have shrunk on arrival.\nThese simple properties hold true for anything derived from magnified materials, which leads us to the problem our colonists face: the native fauna have skin with compressive and tensile strength comparable to steel, given these numbers sit in the tens of MPa and would scale by a factor of 202.\nThe Question:\nCan well-armed 16th and 17th century colonists deter the local wildlife with their weapons, given a scale factor of 20? - Would their rifles or even cannons pierce their hides? What about weak points such as the eyes? - Would polearms be strong enough, and wielded with enough force to do so? - Are there any other weapons available to the Europeans that might prove effective? For instance, an equivalent to Greek fire.\nFor simplicity's sake, we need only consider crustaceans and insectivorous mammals since they are the most likely to be encountered.\nOut of Scope:\nTo keep the question well suited to the site's format, I'll head off some of the more obvious ideas - perhaps to ask about in another question. - Non-violent deterrents such as noise, fire, and offensive scents. - Schemes to use local materials to manufacture magnified gunpowder or similar. - Attempts to create or tame friendly animals. - Arguments involving birds.", "523" ], [ "I foresee hollow protoplanets!\nSince this species develops in a free-fall environment within a space-based cloud of gas littered with resource-rich/-poor asteroids, the first major structures will be built on the asteroids for mining operations. Individuals rarely want to travel long distances to get to work (long is, of course, relative in space), so housing will be built on the same asteroid as the mining facility. As the facility grows, it will need access to more resources, so either the company will start another mining facility or haul other asteroids to an existing one.\nClumps of asteroids then become the foundation for larger settlements, which attract more attention, more business, and more inhabitants, which bring in more asteroids to support the growing population.\nIndependent facilities will produce a similar effect, though in this case \"clumps\" will be individual asteroids connected via trade routes. The collections will attract attention, which brings in business, inhabitants, and more facilities. To prevent unwanted drifting, asteroids would be tethered together to emphasize established trade and transport routes.\nIn either situation, the city is developing in three dimensions, expanding roughly evenly in all directions.", "788" ], [ "This produces a spherical structure, with the oldest buildings at the center.\nTethers and nuts and bolts should be quite capable of holding things together; after all, they do quite well under constant gravitational stress from Earth.\nThe common architecture is going to be something much like what's on the ISS. There's no real down direction, so doors can be in any flat surface, possibly even in cones, corners, or hemispheres. In the case of asteroid clusters, paths of travel will be delineated by the structures themselves, where walls and solid connectors work together to create tunnels through the whole structure. In the case of asteroid collections, paths of travel will, in the macroscale, be defined by the inter-asteroid tethers, while local conditions will be like those for asteroid clusters.\nThe tethers and pipes used to connect structures and asteroids can double as infrastructure. Tethers can provide electricity and fiber optic cable. Pipes supply fresh water and remove waste.\n(All of this ignores the viability question of your scenario, which I am in no way capable of answering.)", "99" ], [ "Plausible design/size of flying cities?\nSetting\nThe setting was a tropical, Mars-sized, ocean-covered world that has completely frozen over. Over the span of several years, the mean global temperature had dropped to below 200 Kelvin. Ice sheets had expanded out from the polar landmasses, as well as from the coastlines of the many chain islands that had peppered the seas, sealing the world in bleakness. Many dozens of millions of humans died in the sudden climate shift, unable to grow food and provide adequate shelter.\n\"Icefall\" lead to the manifestation of great storms that plague the most of the planetary surface. Geothermal activities at previous volcanic island locations drive an engine of jet streams that continuously recycle and resurface the planet of ice and snow. Windspeeds for these storms can occasionally exceed 350 kph, and the rate of fresh snowfall can reach several meters inside a week. Due to the lower gravity, hailstones can rise to greater altitudes and remain airborne for greater durations, increasing hailstone sizes. Inside active storm regions, hail bombards the landscape with stones sometimes large enough to crush a man. On the relatively flat plain of the previous world-spanning ocean, storm structures are allowed to travel far with little topological obstructions and benefit from many geological \"hotspots\", before whirring off in some polar direction.\nAll in all, due to constant tempestuous winds/explosive blizzards, heavy snowfall, and destructive hail, it is essentially impossible to settle the surface at almost any latitude above or below the equator.\nThe poles, however, provide some safety. Both poles are home to the planet's greatest mountains. Storms that meander their way far north or south break and dissipate against the rougher terrain. Most humans who survived Icefall had done so in these polar \"safe-havens\".\nSpecial circumstances\nTo go any further, I have to explain a piece of Clarketech. Without going into much detail: after the onset of Icefall, a kind of biannual meteor shower takes place.", "922" ], [ "Hundreds of thousands of tons of metal and slag enters the atmosphere and impacts around the globe. Among the debris are objects called \"spinners\". Spinners are two identical, long, bar-like rectangular prisms adjoined by a common face, counter-rotating w.r.t each other, typically at rates of rotation no greater than a few RPM. They're made from a metal that is, for all intents, indestructible, and no amount of ungodly force can slow their rate of counter-rotation, betraying a near-infinite torque and tappable work.\nI should also note that for reasons mostly unimportant to the question, the human civilization is technologically suppressed by some unworldly force. Transistors and diodes fail erratically, and anything more advanced just does not function. The planet is also extremely metal-poor. The pre-Icefallen civilization was stuck firmly in a sailing ship era and could not leave the planet when hell broke loose.\nWhy flying cities?\nThe survivors of Icefall colonized the polar mountains and eventually re-established contact with one another via planes powered by \"spinner engines\"--simply engines capable of gearing up the slow yet inexhaustible rotation of spinners for more useful applications. They shared what technologies and methodologies they developed to thrive in the new climate and bootstrapped themselves up to an industrial civilization to rival the former of the sailing ship era.\nAlthough the poles harbor many of the world's storm \"shadows\", there is a hard limit to how many people may be sustained by the crops, cattle, and timber grown there. A limit that encroached. Many city Lords recognized this, as well as how indefensible their territories were given the mountainous obstructions, the irregular and sometimes isolated arrangement of vital infrastructure, and the various angles of attack possible by neighboring states--the proverbial eggs in one basket.\nStorms typically occupy the atmosphere up until around a couple dozen kilometers above the surface. (Due to the lower gravity, the atmosphere is much taller at around 160 km.) The environment above the storms reduces to a kind of trade winds; bands of steadily moving air connecting north and south, adjoined to the low-pressure equatorial belt.\nAs expansion across land halted, expansion into the skies began. It is often easier and cheaper to build airborne superstructures than it is to fight a war with a neighboring city. It is also easier, as a city Lord, to keep your power and influence consolidated if your flying \"cities\" are large and indivisible. A flotilla of small flying craft for example could succumb to a political division, and it's no good pouring money into expanding your feudal Lordship if half of it could fly away at the drop of a hat.", "302" ], [ "TL;DR: It depends on what you mean by \"all out nuclear war\", and whether or not you plan to remain in the same place post-war... but generally speaking, the farther north or south of the equator, the better, with both the north and south poles receiving the lowest exposure over time due to more self-contained wind patterns. Politically speaking, it's really anyone's guess what might happen, so I'd say you have creative free rein on that.\nAs for physically surviving the weapons themselves, consider this: by 1962 (after hundreds of above-ground tests conducted by the US, USSR, UK and France), there was no place on the surface of the Earth where radioactive isotopes from nuclear weapons could not be found, thus prompting the first international treaty to limit testing in 1963, followed by the \"SALT\" talks in the 1970's.\nSo if you're talking about the \"mutually assured destruction\" scenario from the time of the Cold War, where literally thousands of nukes would explode on the same day, then the dispersion of radioactive material would be so immense that no place on Earth would be even close to \"safe\" for many years, possibly even resulting in the fabled \"nuclear winter\" scenario (nobody really knows for sure). An \"all out nuclear war\" today would likely involve far fewer, but they are also likely to be far more powerful weapons, thus producing higher local damage with less global fallout. Either way, if any combination of the major nuclear nations today engaged in an \"all out nuclear war\", it's pretty safe to say that a very large portion of life on Earth would be extinguished within about 6 weeks time, mostly due to the global dispersion of neutron-active isotopes. Of course, due to the enormous number of people on the planet, there would still always be some survivors living in pockets here and there depending on their local geographies and prevailing winds.\nThere are two primary radiation risks. The first is the the instantaneous (speed of light) exposure to the immense energy released by each blast. This is full-spectrum electromagnetic energy, from long-wave, to infrared (heat), all the way through the visible, x-ray, and even gamma rays. The exposure to this would generally have the same devastating impact on all life forms above sea level that are not at least partially protected by very significant barriers like mountain ranges. (Some x-rays and all gamma rays would still pass through mountains, but the lower frequencies will not.) The intensity of exposure will depend on distance.", "435" ], [ "Line of sight exposure drops off at the rate of the inverse square law (at double the distance, one receives one fourth the intensity; at triple the distance, one receives one ninth the intensity, etc.). If a human is exposed to this direct radiation and they survive the blast, they may have severe burns, or extreme dermatitis which may still kill some in the first hours or days. Marine life would be minimally impacted by the initial blasts, affecting only that which is close to the explosion.\nThe other risk is, of course, the fallout. It would affect all surface life that receives it. It would affect marine life as well, with the worst effects in the shallow regions and less so in the deep. There are many factors that affect the amount of radioactive particles that get ejected into the stratosphere, among them the proximity of the detonation to bodies of water and the altitudes at which the individual weapons are detonated. Most of the deadly radioactive isotopes created by a nuclear explosion are very heavy, and would gradually, but slowly, sink into the ocean depths, but losing their effect over time.\nRadioactive isotopes decay at roughly a rate of a 7:10 ratio between time and intensity (for each 7x increase in the amount of time since the blast, the radioactivity of its fallout decreases by about 10x), but the bigger the blast, the more of those isotopes are floating around in the first place and eventually it all settles on the ground. Most estimates speculate the lethality of any particular bomb's fallout to last on the order of months, but of course, the areas closest to ground zero will receive the greatest volume of fallout and will remain dangerous for a longer period of time.\nBottom line: there are such a large number of variables affecting survivability that for your world-building task, a tremendous range of outcomes are plausible, which gives you a lot of wiggle-room to create it the way you want. In order to minimize the overall threat, my advice would be to focus on dry mountainous regions located at latitudes greater than 30 degrees either north or south, with locations on whichever side of the mountain range receives less precipitation. At between 30 & 60 degrees of latitude, the drier side of the mountains would typically be the East side, and at even higher latitudes, the drier side of the mountains would typically be the West side.\nBest of luck with your project.", "435" ], [ "The origins of the words \"port\" and \"starboard\" may be useful to consider here. Early ships did not have a rudder built into the hull, but instead used a modified oar - or later, a larger and more sophisticated steering-board - positioned at the helmsman's right hand. To prevent damage to these devices, the opposite side of the ship had to be moored to the wharf, hence \"port side\" and \"steer board side\". A certain amount of lexical drift resulted in \"starboard\" for the latter.\nThe practical upshot is that port and starboard are synonyms for left and right respectively in the direction of travel. So they only make sense for a vessel which has reasonably consistent \"forward\" and \"up\" vectors.\nThe ISS, even though it is a space station existing in microgravity, is such a vessel:\nNominally, the ISS flies in an LVLH (Local Vertical Local Horizontal) attitude. That means that the vehicle pitches at four-degrees-per-minute in order to keep its belly pointed towards the Earth. So, nominally, the orientation of the ISS appears rather consistent with respect to the Earth.\nThis is desired because the vehicle was designed to be in an attitude in which the comm antennae pointed up at the TDRSS, the GPS antennae point up at the GPS satellites, the thickest shielding is in the direction of greatest debris damage risk, the windows point towards Earth for Earth observation science, and other external payloads can point at their desired topic, consistently.\n<PERSON>, NASA\nHowever, this would not be true of a wheel-type or cylinder-type rotating space station, whose gyroscopic properties would keep it pointed along a consistent axis instead of in \"local attitude\" - unless the axis of rotation happened to be aligned with the plane of orbit.", "947" ], [ "That would actually be a reasonable orientation for a wheel-type station, but not for an O'Neill cylinder which must keep its axis pointed towards the local sun.\nA far more reasonable organisation for both types would be compass directions. As seen from above the North Pole, the Earth rotates anticlockwise, resulting in the Sun appearing to rise in the East. Analogous definitions result in natural N/S/E/W directions in a rotating wheel or cylinder. Up and down would be reversed relative to a rotating planet (ie. up is inwards), due to the direction of apparent gravity.\nNote however that a common design for <PERSON> cylinders is as a pair, rotating in opposite directions, so that the common axis can be precessed to follow the sun through its orbit. In such a design, north and south would be at opposite ends in each cylinder, so would not be useful for locating external non-rotating parts of the station (though residents probably wouldn't care). In such cases, an additional set of directions based on the \"hot\" and \"cold\" ends may prove helpful.", "15" ], [ "I believe that a realistic answer to this will heavily depend on your universe's current understanding of human sleep patterns. Historical records indicate that prior to the easy access to artificial lighting, people used to sleep in two, 4-hour chunks, separated by a waking period of 1-2 hours. A psychiatrist's experiment in the 1990s confirmed this pattern. One study indicated that access to artificial light has shortened our sleep periods by about an hour; seasons also caused variation.\nThe best long-term case studies that I know of for someone living in a completely artificial light environment occurred over a period between 1962-1972 by the French scientist <PERSON>. In 1962, he spent two months in a cave, notably without access to a clock or calendar, in an attempt to determine what natural biorhythms would develop in such an environment. In 1972, he repeated the experiment, staying in a cave for six months. For those interested in reading more, the latter experiment was covered in the March 1975 issue of National Geographic in a piece entitled \"Six Months Alone in a Cave\" (summarized here).\nPhysiological effects included:\n* developing an extended 25-26 hour sleep/wake cycle, with some occurrences of a 48-hour sleep/wake cycle (36 hours awake, 12-14 hours asleep)\n* a subjective experience of the passage of time; he experienced it ~2x slower than it was in reality (from the 2-month experiment)\nThere have also been other experiments done as test runs for living in space habitats.", "551" ], [ "The Russian MARS-500 isolation experiment between 2007-2011 simulated a 105-day stage and later a 520-day mission; it's assumed that this closed habitat had no access to natural light. The data on physiological changes is sparse, but articles indicate that circadian rhythms were effected, and that in general, astronauts are plagued by sleep issues.\nWhat do we do with all these facts?\nYou'd need have some semblance of conformity to a natural sleep cycle unless you want your residents chronically fatigued, irritable, etc. There would be natural limits to wake periods due to physical exhaustion, of course (if we're ignoring biomedical enhancements or pharmaceuticals).\nShift systems might be based on the length of an orbital cycle, if the artificial environment is orbiting a planetary mass. This could be merely for convenience's sake, if the station is coordinating with people working on the planet who are subject to a more traditional day/night cycle.\nMaterial resources are also a consideration; in <PERSON> recent science fiction novel Seveneves, he posited that staggering wake/sleep cycles across a space station's population would prevent a strain on life-support systems and allow it to support a larger population. This did allow for some overlap between people on different \"shifts\", for work collaboration & social interaction. Special attention was paid to being cognizant & respectful of seeking someone's attention during their sleep period. In your universe, this could be imbued via the development of cultural practices and the implementation of shared calendar/contact systems that warned someone if they were trying to digitally interact with a person who was in a sleep period.", "551" ] ]

[ 1991, 8125, 9620, 3125, 351, 11131, 3526, 7201, 9032, 7523, 5839, 6857, 4323, 7631, 10515, 2392, 2622, 8163, 8882, 7005, 4276, 2016, 7587, 6517, 986, 7249, 8928, 628, 7042, 6452, 10999, 2968, 4980, 11397, 4987, 1373, 1164, 9197, 8602, 5116, 1753, 8834, 10264, 180, 3441, 2897, 1522, 6238, 187, 6288, 27, 6477, 2123, 4966, 4964, 8577, 9495, 10215, 1422, 5975, 1703, 7988, 4833, 10349, 561, 1096, 4755, 7562, 8141, 6396 ]

[ [ "Pegasus spyware revelation indicates Indian state snooping on journalists, activists and politicians · Global Voices\nA watchtower in the US area of the special ammunition depot in the Dernekamp hamlet, Kirchspiel, Dülmen, North Rhine-Westphalia, Germany (<PERSON>, CC BY-SA 4.0)\nThe Pegasus Project, a collaboration of 17 media organisations, released a report on July 18 detailing the potential hacking and illegal surveillance of 50,000 phone numbers, mostly in countries with authoritarian regimes, through the use of the Israeli-made spyware Pegasus. The targets of this alleged espionage include human rights defenders, activists, journalists, politicians, high-ranking public officials and business people. Reportedly, more than 1,000 phone numbers from India are a part of this list.\nPegasus users can access unencrypted content stored on a phone (messages, emails, photos, videos, etc.), record phone calls, track geo-locations and activate microphones and cameras without the user's authorization.\nThe leaked list of Pegasus targets includes two phone numbers of <PERSON>, a member of the Indian Parliament and the former President of the Indian National Congress (INC), who was unsuccessful in his election campaign against the incumbent Indian Prime Minister <PERSON> in 2019. The Guardian noted that the selection of Indian phone numbers coincided with <PERSON>'s 2017 visit to Israel that led to significant growth in the relationship between India and Israel. INC, the main opposition party in the Indian parliament, has accused <PERSON> of ‘treason’ and compromising the country's national security.\nAlso included on this list is the phone number of former bureaucrat <PERSON>, who was an election commissioner in 2019. As commissioner, he argued for imposing sanctions on <PERSON> for his heated political speeches, which were linked to increased attacks on Indian Muslims.\n<PERSON>, India's Minister of Railways, Communications and Electronics and Information Technology and <PERSON>, the Minister of State for Jal Shakti (the water ministry), are two recently sworn-in ministers whose numbers have also been found on the list. Incidentally, <PERSON>'s ministry oversees India's digital surveillance regulations.\nWhat is Pegasus?\nPegasus is a type of spyware — a software that allows users to secretly gather and receive data in someone's phone, computer or electronic device — made by Israeli tech firm NSO Group.\nThe Pegasus Project includes 80 journalists from 17 media organizations from 10 countries, with Paris-based media not-for-profit Forbidden Stories coordinating and the human rights not-for-profit Amnesty International overseeing forensic tests.", "534" ], [ "<PERSON> and <PERSON>, the two founding editors of the Wire, an independent Indian media organisation that is assisting in the investigations, both had devices infected with Pegasus. One other editor from the Wire and three regular contributors also had their phone numbers on the list.\nAmnesty's Security Lab produced a detailed technical report after analyzing the leaked list. So far they have analysed 67 phones and found traces of Pegasus in 37 of them. Citizen Lab, an interdisciplinary research lab based at the University of Toronto, Canada has independently reviewed and approved Amnesty's forensic examination methods.\nBREAKING: massive, global leak of the targets of NSO Group's Pegasus spyware. *huge deal.*\nForensic investigation by @AmnestyTech\nin collaboration with @FbdnStories reporters.\nWe @citizenlab conducted peer review.\nHere's an explainer THREAD.https://t.co/TasFCy5EGW pic.twitter.com/rGGKAkfSry\n— <PERSON> (@jsrailton) July 18, 2021\nWhile having a phone number on this list does not necessarily confirm that the phone has been infected with Pegasus, the users of these phones can theoretically be targetted by one of the NSO Group's clients. The Amnesty Security Lab has also published the Mobile Verification Toolkit (MVT), an open-source mobile forensic tool to simplify the process of gathering and analysing data from potentially compromised Android and iOS devices.\nThe aftermath in India\nReporters Without Border calls India ‘one of the world’s most dangerous countries for journalists trying to do their job properly’, while placing the country's Press Freedom Index at 140 out of 180 ranked countries. Journalists like <PERSON> cited conscious efforts to not report about the Pegasus Project in mainstream Indian media outlets.\nLesson for journalists: A controlled way to kill a story in the headline and by prioritizing down information in the main text. pic.twitter.com/YvXgEZuA19\n— <PERSON> (@nit_set) July 20, 2021\nThe range of potential Pegasus victims is huge.", "534" ], [ "What do we know about the ‘Great Firewall of India’? · Global Voices\nScene during clashes between security forces and students at Islamia college of science and commerce in Srinagar. Image by <PERSON>. Used with permission.\nAfter five months of complete internet shutdown in the federally-administered Indian union territory of Jammu and Kashmir, only partial internet access has been restored after the interference of the Indian Supreme Court on January 10, which called the shutdown ‘‘unconstitutional’’.“Freedom of internet access is a fundamental right”, said Justice <PERSON> who was a part of the bench that gave this verdict.\nThis shutdown marks one of the longest ever internet shutdowns in any democracy around the world, and is viewed by experts as a potential signal of the rise of the ‘‘Great Firewall of India’’. The term “great firewall’’ is used to refer to the set of legislative and technical tools deployed by the Chinese government to control information online, including by blocking access to foreign services and preventing politically sensitive content from entering the domestic network.\nWhile the Chinese firewall has evolved as a very sophisticated internet censorship infrastructure, the Indian one is yet to get organized into a large-scale and complex structure. India's tactics to control information online include banning entire websites and services, shutting down networks and pressuring social media content to remove content on vague grounds.\nRead More: India partially lifts communications blackout in Kashmir, internet still down\n301 websites whitelisted\nAccording to internetshutdowns.in, a project that is tracking internet shutdowns in India and created by legal nonprofit Software Freedom Law Centre, the shutdown that was imposed on August 4, 2019, has been the longest in the country and was only partially lifted in Kargil on December 27, 2019, while the rest of the state was still under the shutdown.\nLandlines and mobile communications services were also blocked in addition to regular internet services.", "206" ], [ "Although the “verified users” of the Kashmir valley saw 2G services working on January 25, 2020 with access to only 301 white-listed websites (153 initially which was later expanded to 301), social media, Virtual Private Networks (VPNs) and many other sites remain banned.\nThe administration of J&K passed an order on 25th January ordering for the restoration of 2G internet for around 300 whitelisted websites. We spoke to <PERSON> about this and this is what he has to say about the current situation of Internet in #Kashmir #LetTheNetWork pic.twitter.com/L9zSjVfvWL\n— InternetShutdowns.in (@NetShutdowns) January 31, 2020\nInternetshutdowns.in also tweeted on February 4, 2020 that some of the whitelisted 301 sites were still inaccessible:\nAn order was released on 25th January 2020 by the administration of J&K allowing internet access on 2G for 301 whitelisted websites. We asked a user to access some whitelisted websites on 2G.\nThis is what was found. #LetTheNetWork #KeepItOn #JammuAndKashmir pic.twitter.com/s7V2NqaHBd\n— InternetShutdowns.in (@NetShutdowns) February 4, 2020\nIndependent research indicates many facets of the white-listing such as violation of India's net-neutrality rules, political nepotism and potential surveillance by favoring unencrypted JioChat — an app by Indian conglomerate Reliance allegedly favored by the <PERSON>-led government according to media reports— while banning end-to-end encryption-based chat services like WhatsApp.\nIndia's “Great Firewall’’\nThe Logical Indian reported on January 30, 2020, that broadband services in Kashmir will be be restored only after the creation of an alleged social media firewall. It is currently unclear whether these restrictions will only be imposed in Kashmir or in other areas of India as well.\n<PERSON>, General Manager of Bharat Sanchar Nigam Limited (BSNL), a public mobile and broadband carrier, told the digital news platform that his company is working on a developing “a firewall’’:\nWe have called a team of technical experts from Noida and Banglore who are working over creating a firewall to thwart any attempt by the consumers to reach to the social media applications[..]\nInternet Service Providers like mobile internet carriers were asked by the government to install “necessary firewalls” while “white-listing” the list of allowed websites in an order dated January 13, 2020.\nJust wrote this: The beginnings of the great firewall of India?https://t.co/bSs0L4L4xw\n— <PERSON> , https://mstdn.", "206" ], [ "India’s Latest Internet Shutdown Hits Haryana and Punjab · Global Voices\nIndia internet shutdown map, January 2010 – March 2017. Created by the Centre for Communication Governance (CC BY)\nInternet and mobile services were shut down for several days in the northern Indian states of Haryana and Punjab over a court ruling in the criminal case against guru <PERSON>, the controversial leader of the hugely popular Dera Sacha Sauda sect.\nOn August 25, the special Criminal Bureau of Investigation court reached a verdict that the guru would serve 20 years in prison for two counts of rape. The decision led to the eruption of violent protests, mainly among his followers, in the Haryana and Punjab provinces as well as some parts of Uttarakhand. At least thirty people died and hundreds were injured as a result.\nAhead of the chaotic dissent, authorities suspended internet and mobile phone services in the Haryana and Punjab provinces, home to over 25 million people.\nWhat happened in Haryana? #internetshutdown ? pic.twitter.com/9r35DHlxDw\n— Chinmayi Arun (@chinmayiarun) August 24, 2017\nMobile internet services suspended in #Punjab, #chandigarh and #Haryana for 72 hours.\n— APN NEWS (@apnnewsindia) August 24, 2017\nAccording to the Haryana Additional Chief Secretary <PERSON>, the order was intended to prevent any disturbance of peace and preserve public order.\nBut the reality was not so simple. The shutdown disrupted the lives of citizens across the provinces who were unable to communicate using SMS, 2G, 3G, 4G, CDMA, GPRS systems. India is the world's second largest mobile phone market after China and much of its burgeoning digital economy depends upon mobile phone networks across the provinces.\nIn combination with the physical riots, the shutdowns affected myriad aspects of civic life, from garbage collection to schools to commercial traders.\nInternet users of punjab & Haryana right now ~ pic.twitter.com/8RERDFvYyh\n— ︎︎ ︎︎ ︎︎ ︎︎ ︎︎ ︎︎ <PERSON> August 29, 2017\nCan someone tell me why internet was barred in Punjab and Haryana ?????\nGovernment Mind\n— <PERSON> (@mehra116) August 29, 2017\nAs of August 29, mobile internet and SMS services were restored in Haryana province.\nIn 2016, the UN passed a non-binding resolution to protect freedom of expression by condemning active disruption, shutdown, or suppression of the internet which is fundamental to information sharing and access. But this has not had much impact on the prevalence of internet shutdowns in India, despite criticism that they are ineffectual and stifling of individual and press freedoms.\nAlthough different institutions use unique technical criteria to define a shutdown, none dispute that they have risen rapidly in India in recent years.", "206" ], [ "According to the New Delhi-based Software Freedom Law Centre, India has seen 106 internet shutdowns since 2012.\nIn the Indian state of West Bengal, the internet was shut down on June 18 to control the recent unrest caused by the <PERSON> separatists. The ban has been extended by the local authorities a few times, thus leaving the region without connectivity for more than two months.\nInternet ban in #Darjeeling extended till September 7. Ban since 18June. The joke's on @_DigitalIndia @MIB_India @rajnathsingh @KirenRijiju\n— <PERSON> (@subalternCry) August 24, 2017\n@DoT_India been two months since internet ban in Darjeeling. Is that what you call #DigitalIndia . Please open the net services\n— <PERSON> (@mahesh51195) August 19, 2017\nOn August 7, the Indian Ministry of Communication released a memo intended to codify the process for imposing an internet shutdown through two channels: by the central government and by the state government, whose requests must be reviewed within 24 hours of their submission.\nIn their analysis of the order, local tech policy blog Medianama noted that it does not explain how shutdown agreements are reached. As shutdowns already infringe on the UN’s resolution for freedom of expression online and enact collective curfew on all internet users, the new rule has worrying implications not just for internet freedoms but for the economic and social order of an increasingly digital India.\nFollow the Software Freedom Law Centre's Internet Shutdown Tracker for up-to-date records of shutdowns across India.", "424" ], [ "Social media companies could be liable for user-generated content in India · Global Voices\nTwitter headquarters in San Francisco, US. Image via Wikimedia Commons by User:FASTILY. CC BY-SA-4.0.\nTwitter found itself outside India's ‘safe harbour’ intermediary liability rules that normally provide legal protection against its user-generated content on June 16. <PERSON>, the Minister of Law and Justice, Electronics and Information Technology and Communications of India, elaborated in a series of tweets on how the company failed to comply with the 2021 Information Technology Rules of the 2000 Indian IT Act. In response, In late June, Indian news outlets the Quint and the Wire filed petitions to the Delhi High Court challenging the constitutional validity of these rules.\nHearing update: Petitions filed by @TheQuint and @thewire_in challenging the validity of Information Technology (Intermediary Guidelines and Digital Media Ethics Code) Rules, 2021 are listed before the Delhi High Court. We will observe the proceedings and keep you updated. (1/n) pic.twitter.com/NP8krOES4J\n— Internet Freedom Foundation (IFF) (@internetfreedom) June 28, 2021\nWhile <PERSON> has been highly vocal about Twitter's alleged non-compliance with India's IT Rules, many free-speech activists and civil society representatives suggest that the rules themselves are the problem. The United Nations Special Rapporteurs on freedom of expression, privacy and right of peaceful assembly released a report on June 11 underlining how the rules ‘do not appear to meet the requirements of international law and standards related to the rights to privacy and to freedom of opinion and expression.’\nRead More: How India's new internet regulations will change social media, online news and video streaming\n<PERSON> announced Twitter's noncompliance a few hours after police lodged a report in Ghaziabad in the Indian state of Uttar Pradesh, where a 72-year-old Muslim man was assaulted by five Hindu nationalist men.", "607" ], [ "Many Twitter users tweeted about this event, and Twitter eventually restricted tweets from 50 users related to this incident by the request from India's IT ministry.\nThere are numerous queries arising as to whether Twitter is entitled to safe harbour provision. However, the simple fact of the matter is that Twitter has failed to comply with the Intermediary Guidelines that came into effect from the 26th of May.\n— <PERSON> (@rsprasad) June 16, 2021\nThis announcement occurred right after Twitter's alleged non-compliance with the IT Rules. The Indian government has repeatedly attempted to have tweets taken down that are critical to the government. <PERSON> and many others affiliated with BJP had in mid-May falsely accused the Indian National Congress of developing a ‘toolkit’ to hurt the image of Indian Prime Minister <PERSON> during India's second wave of the COVID-19 pandemic in 2021. The Indian government then warned Twitter in mid-May to remove the ‘manipulated media’ flag for tweets by BJP spokesperson <PERSON>. In late May The Delhi Police raided the Twitter office.\nRead More: Twitter vs India: The battle of BJP and Congress over a ‘fake toolkit’ on COVID-19\nThe Centre for Internet and Society, a respected Indian policy research organisation, suggested in a detailed report on intermediary liability in India that Section 69A of the IT Act has been abused by the Indian government as a justification for the removal of content that is constitutionally protected as freedom of expression. The authors of this report fear that the IT Act is undermining social media companies’ ability to protect human rights on their platforms.\nOn June 29, the Indian journalist <PERSON> from the Quint claimed that a police report was filed against Twitter India's Managing Director <PERSON> by the Bajrang Dal, a Hindu nationalist militant organisation. Bajrang Dal, BJP and a range of other right-wing, Hindu nationalist organisations constitute the Sangh Parivar that is led by the paramilitary organisation Rashtriya Swayamsevak Sangh (RSS).\nTwitter India Managing Director <PERSON> has been booked under Section 505 (2) of IPC and Section 74 of IT (Amendment) Act 2008 for showing wrong map of India on its website, on complaint of a Bajrang Dal leader in Bulandshahr.#TwitterIndiaMap #TwitterIndia\n— Kashish (@Kashish_singh2) June 28, 2021\nIntermediaries\nProminent international civil society stakeholders such as Mozilla shared their grave concerns about India's IT rules when they came into effect in February 2021, suggesting they are endangering the open internet.\nThe rules are divided into three parts , with the first defining legal terms, including newly coined expressions such as “significant social media intermediaries” (SSMI, such as Facebook and Twitter), and the second and third parts detailing compliances and requirements.", "424" ], [ "Indian Government Threatens to Revoke Media Accreditation Over ‘Fake News’ · Global Voices\nScreenshot of PostCard News editor <PERSON> via YouTube\nThe Indian Government released a statement that says that a journalist's accreditation can be cancelled if they are found to propagate “fake” or “uncomfortable” news.\nThe announcement came just a week after the arrest of <PERSON> in Karnataka state. <PERSON> is the founder of PostCard News, a site that that is known for publishing unverified rumors that show a strong bias in favor of India's ruling BJP party.\nThe Information and Broadcasting Ministry of the Indian government, led by minister <PERSON>, released a statement on April 2 suggesting that the Press Council of India (PCI) and the News Broadcasters Association (NBA) — the first being a quasi-judicial body and the second being a private association of news channels in the country— should be charged with determining whether news reports are “fake”.\nGuidelines published by India's Ministry of Information and Broadcasting. Image under fair use.\nThe next day, after a huge backlash from many media houses, Indian prime minister <PERSON> advised the Ministry to withdraw the press release, and let PCI regulate such issues.\nNumerous Indian media workers openly opposed the regulation:\nThe sheer chutzpah of <PERSON> sarkar. Serial promoters of #FakeNews on an industrial scale, funding shady propaganda sites, huge troll army & fake degrees galore & trying to muscle the free press\n— <PERSON> (@bainjal) April 3, 2018\nBoth the news about the regulation and the prime minister's intervention has given rise to politically satirical tweets:\n<PERSON> climbs down on #FakeNews order as PM <PERSON> steps in after outcry. My #cartoon for @firstpost #fakenewsbill\nDetails: https://t.co/3jshSUiIMJ pic.twitter.com/qnkHqNXcnw\n— <PERSON> (@MANJULtoons) April 3, 2018\nSensing mounting anger on the “fake news” notification, the PM orders a U-Turn on his own order.\nOne can clearly see a loss of control and panic setting in now.", "1017" ], [ "#BasEkAurSaal\n— <PERSON> <PERSON> April 3, 2018\nWhen journalist forums like the Editors Guild of India acknowledged the prime minister's intervention, it strongly condemned the regulation in the first place and released a statement:\n…The Editors Guild of India strongly condemns the arbitrary manner contemplated by the Union Information and Broadcasting (I &B) Ministry ostensibly to penalise any journalist or media organisation publishing fake news. By notifying that the I & B Ministry will initiate such proceedings, the Government was arrogating for itself the role of policing the media. It would have opened the door for frivolous complaints to harass journalists and organisations to fall in line…\nThe incident also raises questions about the lack of transparency around processes at PCI and the Central Press Accreditation Committee, a federal body that provides accreditation to news media representatives. If these entities became the sole decision-makers about what is — and is not — “fake news” they might fail to deliver justice.\nThe risks of political power holders influencing or even forcing them to behave in a certain way are great, and without transparency in their processes, it would be difficult for media workers or watchdogs to determine whether or not they were acting in the best interests of the public.\nCensorship and soft power over mainstream media in India have become larger issues in the right-wing Bharatiya Janata Party's rule. <PERSON>, Founding Editor of Indian online news portal the Wire, made reference to this in an op-ed:\n[..]if implemented, [the guidelines] will place media organisations at the mercy of trolls, bureaucrats, and politicians and strengthen the already visible trend of self-censorship when it comes to politically sensitive stories[..]", "289" ], [ "‘A Good Day for the Internet Everywhere’: India Bans Differential Data Pricing · Global Voices\nNet Neutrality And Creative Freedom explained. Image from Flickr by <PERSON>. CC BY-NC-ND 2.0\nIndia distinguished itself as a global leader on network neutrality on February 8, when regulators officially banned “differential pricing”, a process through which telecommunications service providers could or charge discriminatory tariffs for data services offered based on content.\nIn short, this means that Internet access in India will remain an open field, where users should be guaranteed equal access to any website they want to visit, regardless of how they connect to the Internet.\nIn their ruling, Telecommunication Regulatory Authority of India (TRAI) commented:\nIn India, given that a majority of the population are yet to be connected to the internet, allowing service providers to define the nature of access would be equivalent of letting TSPs shape the users’ internet experience.\n#TRAIFreesInternet | Key take aways from TRAI’s ruling on Net Neutrality pic.twitter.com/xlFsLb3bZ6\n— CNN-IBN News (@ibnlive) February 8, 2016\nThe decision of the Indian government has been welcomed largely in the country and outside. In support of the move, the World Wide Web Foundation's <PERSON>, also a Global Voices community member, wrote:\nAs the country with the second largest number of Internet users worldwide, this decision will resonate around the world. It follows a precedent set by Chile, the United States, and others which have adopted similar net neutrality safeguards. The message is clear: We can’t create a two-tier Internet – one for the haves, and one for the have-nots. We must connect everyone to the full potential of the open Web.\nA blow for Facebook's “Free Basics”\nWhile the new rules should long outlast this moment in India's Internet history, the ruling should immediately force Facebook to cancel the local deployment of “Free Basics”, a smart phone application that offers free access to Facebook, Facebook-owned products like WhatsApp, and a select suite of other websites for users who do not pay for mobile data plans.\nFacebook's efforts to deploy and promote Free Basics as what they described as a remedy to India's lack of “digital equality” has encountered significant backlash. Last December, technology critic and Quartz writer <PERSON> reacted to Free Basics saying:\nZuckerberg almost portrays net neutrality as a first-world problem that doesn’t apply to India because having some service is better than no service.”\nWhen TRAI solicited public comments on the matter of differential pricing, Facebook responded with an aggressive advertising campaign on bill boards and in television commercials across the nation.", "534" ], [ "It also embedded a campaign inside Facebook, asking users to write to TRAI in support of Free Basics.\nTwo-page Free Basics newspaper advertisement urging Indians to advocate against net neutrality protections before the government. Image widely shared on social media.\nTRAI criticized Facebook for what it seemed to regard as manipulation of the public. Facebook was also heavily challenged by many policy and open Internet advocates including non-profits like the Free Software Movement of India and the Savetheinternet.in campaign. The latter two collectives strongly discouraged Free Basics by bringing public opinion where Savetheinternet.in alone facilitated a campaign in which citizens sent over 2.4 million emails to TRAI urging the agency to put a stop to differential pricing.\nAlongside these efforts, 500 Indian startups including major ones like Cleartrip, Zomato, Practo, Paytm and Cleartax also wrote to India's prime minister <PERSON> requesting continued support for net neutrality—on the Indian Republic Day January 26.\nStand-up comedians like <PERSON> and groups like All India Bakchod and East India Comedy created humorous and informative videos explaining the regulatory debate and supporting net neutrality which went viral.\nHad differential pricing been officially legalized, it would have adversely affected startups and content-based smaller companies, who most likely could never manage to pay higher prices to partner with service providers to make their service available for free. This would have paved the way for tech-giants like Facebook to capture the entire market. And this would be no small gain for a company like Facebook: India represents the world's largest market of Internet users after the US and China, where Facebook remains blocked.\nThe Internet responds\nThere have been mixed responses on social media, both supporting and opposing. Among open Internet advocates both in India and the US, the response was celebratory:\nThis order shows the power of citizen involvement in policymaking. Policymakers are forced to listen if citizens engage. #NetNeutrality\n— <PERSON> (@pranesh) February 8, 2016\nI think this is not just a good day for the Internet in India.", "607" ], [ "Government actions in Sri Lanka Easter bombings raise the question: Is social media helping or hurting? · Global Voices\nThe Kingsbury Hotel in Colombo, Sri Lanka, one of the sites of coordinated bombings that took place in the country on April 21. Photo by AKS.9955 via Wikimedia Commons.\nAs the tragedy surrounding attacks on churches and hotels unfolded in Sri Lanka on Easter Sunday, the Sri Lankan government took the unusual step of preemptively blocking a range of social media sites.\nThe president's office announced a block of Facebook and Instagram, reasoning that they could be used to spread misinformation. Internet censorship research group Netblocks reported evidence that WhatsApp, YouTube, Viber, Snapchat and Messenger were down as well.\nRead more: A series of bomb attacks on churches and hotels spark terror in Sri Lanka\nShutdowns like this are a clear violation of international rights to free expression and access to information. The protection of these rights is especially important in emergency situations, where people may need to call for help or communicate with family and friends to ensure their safety. While internet shutdowns are increasingly used as a tactic by governments to control online expression, pre-emptive shutdowns are quite rare. For instance, Bangladesh justified a block of Facebook, Viber and WhatsApp in 2016 as as a public security measure.\nIt is, unfortunately, not entirely surprising that the Sri Lankan government has taken this route, as Sri Lanka’s long history of communal violence has repeatedly played out in social media spaces.", "841" ], [ "In March 2018, the government blocked Facebook, WhatsApp and Viber as part of its attempt to quell sectarian violence in the aftermath of clashes between Muslims and Buddhists in the city of Kandy, which resulted in the burning of a mosque and attacks on Muslim-owned businesses.\nAt the time, <PERSON>, writing on the citizen media site Groundviews, argued that these bans were counterproductive and ineffective, cutting many people off from important sources of information while tech-savvy and wealthier users simply switched on VPNs to skirt the blocks. Separate studies by the researcher and novelist <PERSON> and <PERSON> found that many people installed VPNs to get around the blocks, and that the shutdowns hurt businesses reliant on social media platforms.\nThose analyses haven’t stopped the Sri Lankan government from repeating and expanding its blocking exercise, this time with the apparent intention of preempting expected misinformation, disinformation and rumor, and to keep people from organizing reprisals.\n<PERSON> reports on Twitter that he’s seeing more people prepared to skirt the blocks.\nJust a general observation: this time, people seemed far more prepared to work around the block. Clearly citizens learned from March, if not the government.\n— <PERSON> ? (@yudhanjaya) April 21, 2019\nOthers are still turning to social media platforms to inform themselves and stay in touch their communities.\nRespect ? Sri Lankans??!\nMassive Kindness ,We All Can Proud !\nBlood donors are flooding , Large number of people donating bloods in hospitals following Government requests #LKA #SriLanka #EasterSunday #EasterSundayAttacksLK #EasterAttackSL #Colombo pic.twitter.com/15pegwOnlV\n— Sri Lanka Tweet ?? (@SriLankaTweet) April 21, 2019\nDespite the fact that it is currently blocked in Sri Lanka, Facebook has launched its crisis response tool to report news, and to help users report whether they have been affected or search for possibly affected friends.\nMixed reactions to knee-jerk censorship\nThe government’s decision to shut down social media has evoked frustration, because such blocks are generally ineffective and cut people off from vital communication channels in a time of need.\nBut others have expressed support for the move. The Guardian quotes a Colombo resident who says that: “Not shutting down social media could have led to people coordinating attacks and riots against Muslims.”\nThe response in Sri Lanka, from both the government and many residents, suggests some collective ambivalence on the question of whether these platforms can have a net positive effect in a situation of emergency.\nThis is a markedly different narrative from what seemed dominant just a few years ago, when social media platforms were lauded as a powerful way to coordinate assistance in times of crisis. Facebook's safety check tool even became a subject of controversy when it was not made available to residents of cities like Beirut, in the aftermath of bombings in 2015.\nBut today there is clearly deep uncertainty regarding the companies’ ability to keep vulnerable users safe in a crisis situation. Hate speech and disinformation appear to be driving factors in this change. In recent years, Sri Lankan digital media experts and advocates have implored social media companies to find ways to contain online hate speech, harassment and disinformation, to little avail.", "424" ], [ "Technology for Transparency: Government Accountability in India · Global Voices\nCorruption is a global threat. It affects developed and developing countries, the private and public sectors, and nonprofit and charitable organizations. The Transparency International 2010 annual report recently pointed out that governments need to integrate anti-corruption measures in all spheres to fight corruption. It is evident that the world needs more than ever before a holistic approach to fight corruption, including battling its the causes, like poverty and weak governance.\nAs the Technology for Transparency Network has mapped different transparency projects around the world, we have been excited to discover how enthusiasm for a more ethical and transparent society is flourishing everywhere, both with the increase use of technologies and with a growing awareness that corruption should not be tolerated by citizens.\nA protagonist of these changes is India, the largest, most diverse democracy in the world. India is a pioneer in open government and open access strategies with an exponentially increasing innovation in technologies. It is not a coincidence that the country that is producing the cheapest laptop in the world is also partnering with other countries such as the United States to foster open government initiatives:\nIndia is at the vanguard of figuring out how to exploit technology and innovation on behalf of democratic accountability. U.S.-based groups, as well as those throughout the developed and developing world, could learn an enormous amount from these efforts.", "803" ], [ "And India may well become a kind of “city on the hill” that other countries look to for lessons on not only how to pull millions of people out of poverty, but also on how to strengthen democratic accountability.\n— US Open Government Blog\nImportant to mention is that India is a federated state with a diversity of languages and realities. That is why many of the initiatives are focused on local transparency and how to hold local authorities accountable, such as the Accountability Initiative, the first case of our second round of global case studies. Project Director <PERSON> shares the project's mission to improve public service delivery:\nOur big vision is to promote an informed and accountable public delivery system. We do this in two ways. For such a system to exist, the government system has to exist in a form that is transparent and responsive to citizens’ needs, and citizens must be empowered with information so they can place their demands and push for greater accountability. All our work is to pull these two threads together. PAISA and Expenditure Track are examples of that. The second aspect of our work is to generate debate on the accountability issue.\nVisit the Technology for Transparency website to explore other technology for transparency projects from India.", "803" ] ]

[ 10683, 4372, 5455, 10837, 6397, 10352, 6506, 2149, 6514, 10989, 3264, 109, 7200, 18, 8412, 3776, 1371, 10330, 130, 10271, 285, 4948, 10195, 3427, 4856, 9775, 2835, 2229, 4128, 8003, 9151, 4632, 9158, 1620, 11122, 7399, 7650, 2938, 272, 9942, 5345, 5351, 6719, 3799, 2498, 8154, 872, 607, 620, 3900, 9170, 2791, 9880, 10704, 8756, 11051, 10450, 10153, 8403, 2730, 6890, 3294, 2722, 5933, 2338, 9599, 3981, 6075, 3067, 6807 ]

[ [ "Finding the vector potential of magnetic field via line integration\nIf we look at the relationship between the scalar electric potential and electric field in electrostatics, $\\vec{E} = - \\vec{\\nabla} \\phi$, we can easily invert this relationship by $$ V (\\vec{r}) = -\\int \\limits_{\\vec{r}_0}^{\\vec{r}} \\mathrm{d} \\vec{\\ell} \\cdot \\vec{E} $$ where $\\vec{r}_0$ is arbitrary.\nThis got me thinking; is the same possible for magnetic field $\\vec{B} = \\vec{\\nabla} \\times \\vec{A}$? Can we find $\\vec{A}$ (in some specific gauge) from $\\vec{B}$ by inverting this relationship in terms of a line integral (I'm aware of finding $\\vec{A}$ from current distribution, but that's a volume integral and it involves sources, which I'd like to avoid).\nSo I made a guess: $$ \\vec{A} (\\vec{r}) \\overset{?}{=} \\int \\limits_{\\vec{r}_0}^{\\vec{r}} \\mathrm{d} \\vec{\\ell} \\times \\vec{B} $$\nOf course, we need to verify that this is correct (it isn't, but it's only a constant factor), which we can do $$ A_j \\overset{?}{=} \\varepsilon_{jab} \\int \\limits_{\\vec{r}0}^{\\vec{r}} \\mathrm{d} \\ell_a B_b \\quad \\to \\quad \\left( \\vec{\\nabla} \\times \\vec{A} \\right)_i = \\varepsilon{ikj} \\partial_k A_j = \\varepsilon_{ikj} \\varepsilon_{jab} \\partial_k \\int \\limits_{\\vec{r}_0}^{\\vec{r}} \\mathrm{d} \\ell_a B_b $$\nI'm not so sure about this, but from what I understand, a derivative acting on a line integral like this will pluck out the index of the line element, $\\mathrm{d} \\ell$, in this case, $a$ becomes $k$ $$ \\left( \\vec{\\nabla} \\times \\vec{A} \\right)i = \\varepsilon{ikj} \\varepsilon_{jkb} B_b = \\left( \\delta_{ik} \\delta_{kb} - \\delta_{ib} \\delta_{kk} \\right) B_b = B_i - 3 B_i = - 2 B_i $$\nSo the correct formula would seem to be $$ \\vec{A} (\\vec{r}) \\overset{\\checkmark}{=} - \\frac{1}{2} \\int \\limits_{\\vec{r}_0}^{\\vec{r}} \\mathrm{d} \\vec{\\ell} \\times \\vec{B} $$\nI verified that this should be the case on a simple magnetic field $\\vec{B} = B_0 \\hat{z}$ and for path that is a straight line between $\\vec{r}_0 = \\vec{0}$ and $\\vec{r}$. In that case $\\mathrm{d} \\vec{\\ell} = \\hat{r} \\mathrm{d} \\ell$. We also need $\\hat{r} \\times \\hat{z} = - \\hat{\\varphi}$ and the integral becomes $$ \\vec{A} (\\vec{r}) = \\frac{1}{2} B_0 \\hat{\\varphi} \\int \\limits_0^r \\mathrm{d} \\ell = \\frac{1}{2} B_0 r \\hat{\\varphi} = \\frac{1}{2} B_0 \\left( -y, x, 0 \\right) $$\nTaking a curl of this gives the original magnetic field.", "903" ], [ "<PERSON>'s law for a current loop being deformed\nI'm working through <PERSON>'s Classical Electrodynamics text (3rd version, chapter 5.15) about <PERSON>'s law:\n<PERSON>'s law is pretty familiar:\n$\\int_c E \\cdot dl = -\\frac{d}{dt}(\\int_s B \\cdot n da)$\nwhich states that the contour integral of the electric field around a bounded surface is equal to the negative time rate of change of the flux bounded by that surface. No problem. Here we have a total derivative and <PERSON> addresses 2 cases.\n\"The flux though the circuit may change because (a) the flux changes with time at a point, or (b) the translation of the circuit changes the location of the boundary\"\nIn either of these cases, it is easy to show that:\n$\\frac{d}{dt}(\\int_s B \\cdot n da) = \\int_s(\\frac{\\partial B}{\\partial t} \\cdot n da) + \\int_c(B \\times v)\\cdot dl$\nby using $\\frac{d}{dt} = \\frac{\\partial}{\\partial t} + v \\cdot \\nabla$ and then applying a \"product rule\", $\\nabla \\cdot B = 0$ and stokes theorem.", "903" ], [ "i.e.:\n$\\frac{d}{dt}\\int_s B \\cdot n da = \\frac{\\partial}{\\partial t}\\int_s B \\cdot n da + (v \\cdot \\nabla) \\int_s B \\cdot n da$\nIn the case where the surface is constant, we can exchange the order of differentiation and integration:\n$\\frac{d}{dt}\\int_s B \\cdot n da = \\int_s \\frac{\\partial}{\\partial t} B \\cdot n da + \\int_s (v \\cdot \\nabla) B \\cdot n da$\nI still have no problem with this. Now we can work on the second term on the right (apply a product rule, drop terms with $\\nabla \\cdot B$ and then apply stokes theorem) to get the $\\int_c(B \\times v)\\cdot dl$ term.\nwhich, when applied to <PERSON>'s law gives the nice result:\n$\\int_c [ E' - (v \\times B)] \\cdot dl = - \\int_s \\frac{\\partial B}{\\partial t} \\cdot n da$\nThe problem arises when you allow the shape of the bounded surface to change. (Consider a circular wire loop in a magnetic field that you then hit with a hammer causing a dent in one side). How does changing the surface influence the result that we derived above? It seems to me that this would prevent us from being able to exchange the order of differentiation and integration which seems like it leaves us in a pretty tight spot ...", "903" ], [ "What is the relationship between the electric field induced by a uniform and infinitely wide magnetic field?\nI have been contemplating on how to solve for an $e$-field produced by a changing $b$-field, and when simplifying the differential equation, I ran into a problem where the integral form of Maxwell-Ampere's law does not describe physical reality - but instead gives us a mathematical model to describe what happens to a circuit loop under a changing $b$-field. The problem is, what if I want to actually understand the real $e$-field at every point due to a changing $b$-field? I don't have an interest in knowing the sum total of the $e$-field along an arbitrary loop.\n$\\nabla\\times E = - \\frac {\\partial B} {\\partial t}$\nWouldn't the curl of $E$ of an infinitely wide and uniform $b$-field be zero?\nIf so, then how would a loop inside the $b$-field have an induced voltage?\nBasically, I've been beaten over the head with the integral forms of Maxwell's equations, which only serve some real world practical problems, but cannot fully explain what is actually occurring the reality.\nAm I wrong in believing this?\nEdit 1:\nSuppose we have a dynamic b-field that points in the x direction. It only varies in the z direction.\n$\\nabla\\times E = - \\frac {\\partial B} {\\partial t}$\n$\\frac {\\partial E_y} {\\partial z} + \\frac {\\partial E_z} {\\partial y} = - \\frac {\\partial B_x} {\\partial t} $\n$\\partial E_y\\partial y + \\partial E_z \\partial z = - \\frac {\\partial B_x} {\\partial t} \\partial z \\partial y $\n$E_z = 0 \\leftarrow$ intuition tells me this, I don't see how it could have a value.", "903" ], [ "Maybe this is incorrect.\n$\\partial E_y\\partial y = - \\frac {\\partial B_x} {\\partial t} \\partial z \\partial y $\n$\\partial E_y = - \\frac {\\partial B_x} {\\partial t} \\partial z $\nin finite form\n$\\Delta E_y = - \\frac {\\partial B_x} {\\partial t} \\Delta z$\nWe can see how knowing $\\Delta E$ can be beneficial for a circuit loop. After all, the driver in a circuit is potential difference or the $\\Delta V$ - which is $\\Delta E \\cdot L$ but this doesn't help us much outside of circuits. How would I know the absolute value of E, rather than its relative value?\nI know this question deviates a little from my original one, but I think it's strongly related. Pointing me to any resources will be helpful.", "903" ], [ "Let me take you through deriving the boundary conditions. I had a fantastic Prof, who explained this very well. We can derive them by evaluating some of <PERSON>'s equations at the interface.\nBoundary Condition 1\nFirst, let's assume there is a surface charge density $\\rho_{sf}$. Let's begin with <PERSON>' Law: $$ \\oint \\vec{D}\\cdot \\mathrm{d}\\vec{S} = Q_{encl} $$\nWe used the displacement field here, defined as $\\vec{D} = \\varepsilon \\vec{E}$, and $Q_{encl}$ is the charge enclosed by a Gaussian box we're about to draw. Let's make it a cylinder around the interface, of height $h$.\nIn words, <PERSON>' law states that the net flux of an electric (displacement) field in a closed surface is directly proportional to the enclosed electric charge. Our cylinder is the closed surface - let's work the integral out!\nFirst, there are no constraints on our choice of the Gaussian surface's height, so we can take the limit $h \\rightarrow 0 $.", "903" ], [ "This means the surface integral for the curved surface goes to zero, and we're left with the ends:\n$$ \\int_{top} \\vec{D}\\cdot \\mathrm{d}\\vec{S} = (\\vec{D}1\\cdot \\hat{n})A $$ $$ \\int{bottom} \\vec{D}\\cdot \\mathrm{d}\\vec{S} = -(\\vec{D}_2\\cdot \\hat{n})A $$\nwhere A is the surface area of the top and bottom end of the cylinder, the subscript number indicates the medium and $\\hat{n}$ is the surface normal. Note that for the bottom end, the integral is negative as the surface normal and the displacement field point in opposite directions.\nNot forgetting about charge enclosed $Q_{end}$: in the limit of $h \\rightarrow 0$, this becomes equal to the surface charge density multiplied by the area of the top/bottom surface! So, <PERSON>' law becomes:\n$$ (\\vec{D}1\\cdot \\hat{n} - \\vec{D}_2\\cdot \\hat{n})A = A\\rho{surf} $$\nCancelling $A$ and evaluating the dot products, we end up with the first boundary condition for the displacement field vector component perpendicular to the interface:\n$$ \\boxed{D_{1\\perp} - D_{2\\perp} = \\rho_{surf}} $$\nWe could substitute $\\vec{D} = \\varepsilon \\vec{E}$ here. Also, the presence of a surface charge will depend on the type of interface.\nBoundary Condition 2\nFor the next boundary condition, let's evaluate the integral form of Faraday's Law:\n$$ \\oint \\vec{E}\\cdot\\mathrm{d}\\vec{l} = - \\frac{\\mathrm{d}}{\\mathrm{d}t} \\int \\vec{B}\\cdot\\mathrm{d}\\vec{S} $$\nIn words, this states that for any closed loop path, the sum of the length elements times the electric field in the direction of the length element is equal to the time derivative of the magnetic flux through the surface created by the closed loop path.\nSo, let's draw a rectangular loop of height $h$ and length $l$ around the interface. We can split the path integral of Faraday's Law up into a sum of 4 parts, for each side of the loop. Again, we can take the limit $h\\rightarrow0$, which means we are only left with the path integrals parallel to the surface:\n$$ \\int_{top} \\vec{E}\\cdot\\mathrm{d}\\vec{l} = (\\vec{E}1 \\cdot \\hat{n})l $$ $$ \\int{bottom} \\vec{E}\\cdot\\mathrm{d}\\vec{l} = -(\\vec{E}_2 \\cdot \\hat{n})l $$\nwhere $\\hat{n}$ is the unit vector in direction of the loop. Not forgetting about $\\int \\vec{B}\\cdot\\mathrm{d}\\vec{S}$: in the limit of $h\\rightarrow 0$, as the surface area of the enclosed path goes to 0, $\\int \\vec{B}\\cdot\\mathrm{d}\\vec{S} = 0$.", "707" ], [ "I feel really bad for the OP getting these downvotes. The question (if worded better) is a really good question. There is obviously a lot of confusion over this - given the range of solutions posted. I think the main confusion comes from two places: (1) using current density in place of current (whether consciously or not), (2) Not realizing that a 1-D vector is a scalar.\nCurrent density:\nFor simplicity, assume we have a conductor with a constant conductance, $\\sigma$. Also for simplicity, let's assume that the electric field is time-independent, but could vary in space. The electric field, $\\vec{E}(\\vec{x})$, is a vector field, that is, at each point in space, we associate a vector space.", "359" ], [ "The relationship between the electric field and the current density in this simplified model is $$\\vec{J}(\\vec{x}) = \\sigma~\\vec{E}(\\vec{x})$$ From this equation, we see that $\\vec{J}(\\vec{x})$, the current density, is also a vector field.\nCurrent:\nThe current is defined with reference to some area as $$I_A = \\int_A \\vec{J}(\\vec{x})\\cdot d\\vec{A}$$ In circuits, the area we care about is the cross-sectional area of the wire. With a DC source the electric field is constant throughout the wire (if AC, still constant spatially but has time dependence), that is $\\vec{E}(\\vec{x}) = E_0~\\hat{z}$ (assuming the wire is along the $z$-axis). This means that the current density is $$\\vec{J} = \\sigma~E_0~\\hat{z}$$ and so the current is (area of interest is the cross-section of the wire, with $d\\vec{A} = dA\\hat{z}$) $$I = \\int dA~\\sigma E_0~\\hat{z}\\cdot\\hat{z} = A\\sigma ~ E_0$$ In this idealized situation, we see that $I$ can be treated as a 1-D vector, so far as the vector space axioms are concerned. We also note that a 1-D vector is a scalar! Note that I am not saying scalar field or vector field.\nLet's see what happens when we aren't confined to a wire and have spatial varying electric fields.\nTake some area through a region in a conductor (with constant $\\sigma$ as before) where the electric field has spatial dependence $\\vec{E}(\\vec{x})$. The current associated with this electric field and area is $$I_A = \\sigma\\int_A \\vec{E}(\\vec{x})\\cdot d\\vec{A}$$ With a little thought, one can see that this doesn't change the argument in our wire case. The current defined this way still produces a 1-D vector, whose direction indicates which way the total flow of positive charges (by convention) is flowing, through the prescribed surface. And again, a 1-D vector IS a scalar.\nNote: in this situation, adding currents is physically identical to adding electric fields (as $\\sigma$ is assumed constant).", "780" ], [ "It's first important to note that in classical electromagnetism, the $\\mathbf{A}$ and $\\phi$ fields are not physical in the same way that the $\\mathbf{E}$ and $\\mathbf{B}$ are. We can't measure them and they aren't uniquely defined.\nGravitational potential energy is a good analogy. Suppose an object is on a table a height $h$ above the ground. We could say that the object has potential energy $U=mgh$, picking the floor to be $U=0$, or that the object has potential energy $U=0$, picking the table to be where $U=0$. In fact, we could choose the gravitational potential energy to be any $U=mgh+C$ for any $C$, as long as we use the same definition of potential energy in the same problem.\nJust like we can add any constant to the gravitational potential energy, we can add some additional vector field $\\mathbf{V}$ to $\\mathbf{A}$. Let's define the new vector potential $\\mathbf{A'}=\\mathbf{A}+\\mathbf{V}$.", "499" ], [ "By the definition of the vector potential, we know $\\nabla \\times \\mathbf{A'} = \\mathbf{B}$. Using the properties of the curl, we find $\\nabla \\times \\mathbf{A'} = \\nabla \\times \\mathbf{A} + \\nabla \\times \\mathbf{V} = \\mathbf{B}$. However, we know $\\mathbf{B}=\\nabla \\times \\mathbf{A}$, so we can write $\\mathbf{B}+\\nabla \\times \\mathbf{V} = \\mathbf{B}$. Therefore, we see that we can add any $\\mathbf{V}$ such that $\\nabla \\times \\mathbf{V}=\\mathbf{0}$. Because of an identity in vector calculus, we know that any curl-less vector field can be written as the gradient of a scalar field, say $\\psi$.\nWhen we go through the math we find that when we change $\\mathbf{A}$ to $\\mathbf{A'}=\\mathbf{A}+\\nabla\\psi$ we have to change $\\phi$ to $\\phi'=\\phi-\\frac{\\partial \\psi}{\\partial t}$.\nSo we don't have infinite freedom in gauges. We have the freedom to choose any scalar field $\\psi$ and then transform $\\mathbf{A}$ and $\\phi$ as above. The two most popular gauge choices are the Coulomb and Lorenz, which are detailed in the Wikipedia article you linked to in your question.", "418" ], [ "From <PERSON>'s law, at steady state, $$ \\vec{\\nabla} \\times \\vec{E} = -\\frac{\\partial \\vec{B}}{\\partial t} = 0 $$ so since $\\vec{E}$ is curl-free, it is the (negative) gradient of the electrostatic potential $V$: $$ \\vec{E} = -\\vec{\\nabla}V. $$\nFrom the continuity equation and <PERSON>'s law, at steady state and for uniform electrical conductivity $\\sigma = 1/\\lambda$, $$ \\vec{\\nabla} · (\\sigma \\vec{E}) + \\frac{\\partial\\rho}{\\partial t} =0 $$ $$ \\vec{\\nabla}\\sigma · \\vec{E} + \\sigma\\vec{\\nabla}·\\vec{E} + \\frac{\\partial\\rho}{\\partial t} = 0 $$ $$ \\vec{\\nabla} ·\\vec{E} = 0 $$ $$ \\vec{\\nabla}^2 V = 0. $$ This is the differential equation you must solve (<PERSON>'s equation), with constant potential boundary conditions on the spherical boundries.\nI'm not sure if an analytical solution exists (I wouldn't be surprised if it does), but we can obtain approximate solution for $V$ for small $a$. If there were two point charges $Q$ and $-Q$ at $\\vec{d}$ and $-\\vec{d}$ in vacuum, the potential at points not on these charges also satisfies <PERSON>'s equation. In this simplified problem, according to <PERSON>'s law, the potential in the vicinity of the point charge at $\\pm\\vec{d}$ would be $$ V(\\vec{r}) \\approx \\pm \\frac{A}{\\lVert\\vec{r}\\mp\\vec{d}\\rVert} $$ where $A$ is some proportionality constant that is yet to be determined. If $ a \\ll d $, a distance $a$ away from $\\pm\\vec{r}$, we enforce\n$$ V = \\pm \\mathcal{E} \\approx \\pm \\frac{A}{a} $$ $$ A = a\\mathcal{E} $$\nThe potential everywhere is given approximately (to the extent $a \\ll d$ is valid) by $$ V(\\vec{r}) = a\\mathcal{E}\\left(-\\frac{1}{\\lVert\\vec{r} + \\vec{d}\\rVert}+\\frac{1}{\\lVert\\vec{r} - \\vec{d}\\rVert}\\right).", "649" ], [ "$$ You can see here why $a = 0$ is problematic. Then, $$ \\vec{E} = -\\vec{\\nabla}V = a\\mathcal{E}\\left(-\\frac{\\vec{r} + \\vec{d}}{\\lVert\\vec{r} + \\vec{d}\\rVert^3}+\\frac{\\vec{r} - \\vec{d}}{\\lVert\\vec{r} - \\vec{d}\\rVert^3}\\right) $$ and $$\\vec{J} = \\sigma \\vec{E} = \\sigma a\\mathcal{E}\\left(-\\frac{\\vec{r} + \\vec{d}}{\\lVert\\vec{r} + \\vec{d}\\rVert^3}+\\frac{\\vec{r} - \\vec{d}}{\\lVert\\vec{r} - \\vec{d}\\rVert^3}\\right). $$ The charge density can be determined from <PERSON>' law: $$ \\rho = \\vec{\\nabla}·(\\epsilon \\vec{E}) = \\vec{\\nabla}\\epsilon · \\vec{E} + \\epsilon \\vec{\\nabla}·\\vec{E} = \\vec{\\nabla}\\epsilon · \\vec{E}. $$ Given $\\epsilon$ as a function of position, you can use this to find $\\rho$. If $\\epsilon$ is uniform, then we simply have $\\rho = 0$. This is typically a good approximation within a conductor at steady state.", "418" ], [ "Vector potential of a solenoid in the Coulomb gauge\nI understand the usual argument for calculating the vector potential outside of a solenoid of radius $R$ with $n$ turns per unit length carrying current $I_0$ using $$ \\oint \\mathbf{A} \\cdot d \\mathbf{l} = \\iint \\nabla \\times \\mathbf{A} \\cdot d\\mathbf{a} = \\iint \\mathbf{B} \\cdot d\\mathbf{a} $$ which gives (in Gaussian units) $$ A_{\\varphi} = \\frac{2\\pi}{c} \\frac{nI_0 R^2}{r} $$ However, I am asked explicitly to find the vector potential in the Coulomb gauge. I have two main questions:\n1) Is showing that this vector potential satisfies $\\nabla \\cdot \\mathbf{A} = 0$ and $\\mathbf{B} = \\nabla \\times \\mathbf{A}$ sufficient? That seems a bit too much like a 'physicist proof' to me.\n2) How can I compute the vector potential explicitly from the form $$ \\mathbf{A} = \\frac{1}{c} \\int \\frac{\\mathbf{J}(\\mathbf{r}',t)}{|\\mathbf{r}-\\mathbf{r}'|} d^3 r $$ I have written $$ \\mathbf{J}(\\mathbf{r}',t) = n I_0 \\frac{\\delta(r'-R)}{R} \\ \\hat{\\varphi} $$ which gives after some algebra and one integration $$ \\mathbf{A} = \\frac{n I_0}{c} \\int_0^{2\\pi} \\int_{-\\infty}^{\\infty} \\frac{1}{\\sqrt{r^2+R^2 - 2rR \\cos(\\varphi-\\varphi') + (z-z')^2 }}dz' d\\varphi' \\ \\hat{\\varphi} $$ But doesn't the integral over $z$ diverge? This integral isn't doable by Mathematica.", "402" ], [ "Have I done something wrong?\nEDIT:\nI suppose I can simplify this integral by (without loss of generality) letting $\\phi = 0$ and $z=0$. The integral becomes \\begin{align} \\mathbf{A} &= \\frac{n I_0}{c} \\int_0^{2\\pi} \\int_{-\\infty}^{\\infty} \\frac{1}{\\sqrt{r^2+R^2 - 2rR \\cos(\\varphi') + (z')^2 }}dz' d\\varphi' \\ \\hat{\\varphi} \\ &= \\frac{n I_0}{c} \\int_{-\\infty}^{\\infty} \\frac{2 K\\left(-\\frac{4 r R}{(r-R)^2+(z')^2}\\right)}{\\sqrt{(r-R)^2+(z')^2}}+\\frac{2 K\\left(\\frac{4 r R}{(r+R)^2+(z')^2}\\right)}{\\sqrt{(r+R)^2+(z')^2}} dz' \\end{align} But this still seems to diverge. How can I show that this reduces to $\\frac{2\\pi}{c} \\frac{nI_0 R^2}{r} $?", "402" ] ]

[ 4016, 6804, 9708, 9786, 7719, 3473, 460, 1807, 10133, 469, 6301, 6574, 786, 7366, 8923, 7750, 11105, 1505, 9738, 1474, 11382, 4281, 10115, 1774, 7815, 8109, 9697, 11069, 7635, 2785, 7397, 1267, 47, 2043, 9370, 5952, 4456, 7642, 4684, 9029, 10190, 2734, 6304, 9167, 7014, 7652, 1436, 11142, 2578, 6453, 11356, 4049, 11020, 9360, 1966, 4157, 7097, 5828, 5192, 6157, 7572, 11143, 4723, 6006, 1912, 10004, 3070, 6029, 11424, 5150 ]

[ [ "Running a successful Prison complex for Wizards\nFirst of, a little parenthesis about how my magic works :\n* Magic is a calculable energy contained in some alloys and people. It can be manipulated in about the same way as electricity (with conductors and isolation)\n* Magic energy can be used as an energy in the same way as oil and is really powerful at that.\n* Wizards (people who can create magic themselves and contain it without their body) can transfer their own magic energy into magic batteries.\n* Wizards can cast spells, those are some sort of mathematical formulae one must known perfectly to be able to cast. Spells can be designed by non-wizards and some of them are too long to remember perfectly.\n* Wizards produce a way greater output of energy than ores. Therefore, they are the one producing most of the energy. Ores are used for all magic related contraption. Such as weapon and batteries.\n* Wizards can pass their energy to other Wizards\n* There is a way to create weapons simulating spells, using magic energy as ammo. Wizards can use them without ammo, providing their own energy instead.\n* Wizards have a limited amount of magic energy per day, it regenerate faster when sleeping and doesn't regenerate much while doing some effort or when starving.\n* There is a way to forcefully extract magic from Wizards, but it is painful and can lead to death.\nIn my world, Magic and Wizards are rare. (About 1 % of the population produce magic energy) Sometimes, you stumble upon bad wizards who keeps using their awesome skills to bother people, by setting them on fire or making them fly at high speed. Those guys need to be punished but how are we going to keep them in ? Even better, how are we going to put them to good use ?\nMy goal is to create some kind of prison that allow us to :\n1.", "227" ], [ "Keep our little mages in the prison\n2. Keep our little mages secure (Need a way to deal with fights between inmates)\n3. Allow our little mages to have a degree of freedom similar to the one of a regular prison.\n4. Make money using our little mages (Enough to be self sufficient would be awesome)\n5. Keep in a reasonable amount of little mages (150 ?)\nAnd then here is our means :\n* MOOOONEY !\n* About 10 wizards collaborators on site (qualified as battle mages, spells makers or other skills wanted)\n* Any number of non-mages collaborators and guards\n* Classified weaponry and spells\nHere is few solutions I have already considered :\n* Keeping our mages sedated. Violates #3 and certainly #4.\n* Keeping our mages on crack at all time so that they cant think of spells. Somewhat violate #3 and may be bad for #4\n* Forcing them to deliver all of their magic energy under a pain spell. Not a solution as they could still use their magic to retaliate and they could still work together to amass a reasonable power. May then be problematic for #1, #2 and #3\nSo here is my questions, what can tactics can I use to make this prison ? To narrow it down, Here is some precise question :\n* How should I arm guards ?\n* How should I build the prison (material) ?\n* What should I do with Wizards that keeps making trouble even in prison ?\n* (Bonus) Ideas on how to suppress the usage of spells ?", "227" ], [ "How to make a metal with extraordinary property worthless?\nIn a RPG scenari, players will look for a MacGuffin Metal (aka MGM.), experiencing the farwest gold fever.\nShort Story:\nContext : Farwest(~1880), steam punk.\n1. First encounter :\nIn a 3-5 minutes time frame, players will have to handle a MGM door.\nMetal property : Lighter than aliminium, strong as steel, silverish.\nInspection method: pick it, move it, throw it, trust into, punch bite and claw.\n2. MGM Discovery :\nAfter the \"MGM fever\", the frenzy and chaos surround thing this quest of a incredible medal, only remain a leaving a bitter taste.\nThe MGM is an already know medal! Already discoverd decades ago by Dr. <PERSON>, he judges it worthless. And he is right.", "183" ], [ "The veins is there near the Xyz town, the mine already exist but somehow the MGM is worthless.\nQuestion :\nHow to make a metal with extraordinary property worthless?\nThe MGM has property that make it comparable to Titanium.\nIn-game restriction :\nThe game cannot accept any kind of Op MGM Armor, or gold like revenue.\nNo full armor or bullet proof vest, light canoe, shield etc.\nThing it can be used for : horse thing, knife, small things with no impact from spoon to frypan\nOut side restriction :\nOne of the player is a engineer in a metalurgy compagny. He knows a lot about metals, and as the knowledge to bring industrial metal into the West if I let him enought time to.\nHe starts his study/career because as a kid he was wondering what it will take to make the bronze age, the steel age.\nHe is the real reason of my question because I'm afraid he could destroy the plot.\nPossible answer I already have:\n* It's magic. It's a precious metal revolutionary! ..Changed my mind it's worthless.\n* You are the engineer, you tell me why it's worthless.\n* Good question, your char ask that but the answer he got is too complexe for him to understand.\nThe answer doesn't need to be hard science, just reasonable enought. You can judge the reasonable based on your own comprehension, Will it fool you? The argument can include magic, curse, haunted. No hard science needed.", "446" ], [ "Analysis\nFrom your statements I deduced this:\n* Hypothesis A: Your machine are immune to madness.\nMany people couldn't even get close to these substances without losing their sanity hence I think machine might fare better.\nThis hypothesis implies your machines are not subject to sanity losses. This implies they can't have any form of emotional intelligence.\n* Hypothesis B: Emotional state of mind is improving magical results but not necessary for magic to be used.\nemotion normally act as catalyst\nA catalyst is a desired but not required compound of a chemical reaction used to increase dramatically the efficiency of this reaction. This implies emotion is a nice to have in your magic framework.\nFacts (as far as I know)\n* Sentience has nothing to do with brain waves. Any brain, from the dumbest to the smartest emits electromagnetic waves. Therefore the machine's brain waves replication capacity is useless.\n* Brain waves is only the consequence of a functioning brain. Generating brain waves would produce no more \"emotion\" from the void than would a light torch do.\nConclusion\nA and B are both true\nAccording to me, it's the better option: the apocalypse.\nSince magic requires sensitive beings the machines can't use magic by themselves.", "227" ], [ "Machines are pure rational beings, optimizing their goal, they can not feel empathy and they would have no reason to care about us. At best they would ignore us until we interfere with their goal and they begin a war in order to remove humanity from Earth.\nIn that scenario it is almost certain that machines -- being incapable of using magic by themselves -- would start to enslave human beings in order to manipulate magic via their slaves making them \"feel\" arbitrarily things according to their needs.\n* Q1: Yes.\n* Q2: Yes.\nA is true and B is false\nIn this scenario, both machine and humans can use magic. Human have no particular advantage over the machines because emotions does not play a role in magical events. It's event worse than the previous scenario because machine would be able to use magic directly.\n* Q1: Yes.\n* Q2: Yes.\nA is false and B is true\nThis scenario implies that your machines are able to use magic exactly as human do because they are sensible and still capable of emotional behaviour -- they could see us as a peculiar and bizarre form of life which gave them birth. The endeavour of understanding and manipulating magic is clearly required for the machines to survive a possible war against humans. Machine are still subject to madness -- I let you free to explain the prospect of a sensitive mad machine -- so they wouldn't be able to be better than humans whatsoever.\n* Q1: Yes (see above).\n* Q2: Yes (idem).\nA and B are both false\nThis is the boring option: man and machines are both emotional beings and all things being equal, magic exists.\n* Q1: Yes (boring).\n* Q2: Yes (hem...).\nPersonal opinion\nI don't think that giving your machine the ability of acting like humans is nice for your scenario because I don't see the point of having perfect human replicas except if your story is NOT about robots.\nThe third option is to define more precisely how magic works so machine are able to learn and use it somewhat in a more efficient way than humans do. Or the opposite.", "44" ], [ "How to survive a bio epidemic?\nI'm a Father. Through the love that we share, I protect my children, show them how to fight. There was time when we don't have to fight, but the Stupi wants our Lovestones for his so-called 'industry'. So.\nIt was the fifth year of the world. Their attacks is less and less frequent. Maybe he is losing interest in killing us. I feel less my children dead from the their skirmish. But things are not getting better. A strange disease is spreading.\nIt started at the borders, no doubt from some evil scheme the Stupi had thought of. My children showed no apparent symptoms that the Mothers could do about. They just suddenly turned ill in a few days and then their love winked out. The Hight Father knew about this, but he had not thought of way to stop it, yet.\nFeeling the love of my children winked out all over the Land, I wanted to freak out, but couldn't - thank to the Mothers. I suspect most of us had been infected, but I'm not sure. Are we all doomed? O Spirits! Show us the way to salvation! How do I protect my children from this?\nNotes:\n1. The only enemy we have is no the south: the Stupi\n2.", "934" ], [ "The rate of winking out is increasing, maybe we have a year, or a month\n3. We only have 150 000 Brothers fit for fighting, spreading all the border to maintain the illusion of the invincible army\n4. The population is gathering at 13 Great Altars around the country.\n5. On the north is the great winter land, we don't know what's up there, we hadn't needed to ventured there before\n6. Our people live with nature, resources were plentiful, we don't make anything new, if the old still serve us well enough (my cloths were of my great grand..)\n7. I have no illusion of getting out of this the easy way, saving even one of the Altar is good enough\n8. The Lovestones were the manifestation of our deceased ones's love, there's nothing magical about it, but we're not giving it away\nEdit 1:\n1. Father is a title of a leader (equivalent of a lord), High Father is the king\n2. Mother is a title of a psychic healer, their only purpose is to maintain the positive emotional atmosphere\n3. Lovestones offer no magical power, they slowly crystallized from nothing where someone (of that race) died.\nThird person perspective: The <PERSON> is a close people. They're not very friendly to strangers. Everything about them is pretty much ambiguous, plenty of rumors, nobody sure. The <PERSON> thought the Lovestones are the source of their psychic power, so obviously his Evilness wants it. The <PERSON> tried many kind tactics against them but couldn't make a noticeable victory in decades. One day, he forced villagers (infected with a terrible disease that is well known in his country) to take up arms and march into the Wussname. Then he quarantine his borders, shoot anything that try to cross and at the same time, lied to his men to continue the attacks as usual to pretend that he had nothing to do with spreading the disease (he had good public image).", "164" ], [ "How could a monarch rule in a vast, isloated, medieval city\nThe City itself\nLet's assume we have a city of the size of the Peloponnese (round about 22'000 square kilometers) which is very dense populated (by medieval terms) and is isolated from the rest of the world (think of something like an ocean surrounding the island). The city wasn't 'planned', it just grew bigger and bigger so the city layout itself is a bit flawed (e.g. bad street layout). Let's for simplicity assume there is enough food for (nearly) everyone.\nThe Population\nAll citizens use the same common language, although many dialects do exist. Nevertheless it's a multi-ethnical population with different religions an different customs. Sometimes the tension between these different culture groups leads to nasty crimes but all in all the situation could be considered as stable. Wealth is distributed pretty bad (as usual) but there is no particular cultural group having a much greater share of wealth than the others.\nThe Government\nNow that’s the questions. I'd like to have a central ruler sitting right in the middle of the city. Given the size of the city, a direct rule however is deemed to be impossible. Therefore, a greater deal of decentralization appears to be required.\nIdeas so far\nFeudalism\nThis is the first thing I had in mind: Have a single king with multiple vassals, which in return have multiple vassals themselves. You get a high decentralization with an acceptable control from the central government/ruler and you get a decent degree of stability. Feudalism also allows for some interesting storylines regarding counts, bloodlines and similar stuff. There are some fatal problems though...\n* Feudalism was built on an agricultural society. The lower vassals had a large mass of peasants beneath them. Feeding people was hard so agricultural land was expensive.\n* Feudalism needed a constant change in borders. The liege gave its vassals land in return for favors or good work which the vassals children inherited on death. Works fine until you got no more land to distribute. I'd like to dispose the idea of the civil war emerging every 100 years because the vassals get greedy for more land or the idea of extreme balkanization of the city until every citizen is a landlord himself.\n'Mayorism'\nThis approach features more bureaucrats and fewer nobles.", "878" ], [ "Each district has a mayor and a smaller council designated to govern the pile of land he's been assigned with. A mayor is not of noble blood but excels in administrative skills. Each mayor may rule until death, after which he is replaced by any other administrative professional from anywhere, or until another person has been assigned to do his job (because the former mayor was incompetent, corrupt or....). There are no elections for the mayor as we don't want the citizens to get a taste of democracy and get uppy against the crown-authority. Up to this point the system would prove pretty stable, but here are some problems:\n* The king most likely has better things to do then to assign each of his thousands of mayors day to day anew. Like in feudalism he'd install multiple layers of administration, that in the end a group of let's say 10 people assign the jobs for him. This would then lead to a concentration of power in the hands of very few people which in return could get come to the conclusion a council of ten people is better than a single king.\n* Bureaucracy was on the rise late 17th or early 18th century which is clearly not an option for a medieval based setting. Writers in ancient Egypt did a similar job and different empires had different people doing the same job too, but all of them used a more or less centralized approach. Using common people for administrative jobs became fancy after bourgeoisie was on the rise and enlightenment was more widely accepted.\nEDIT\nAs there were many question regarding the city. First of all, it’s a fantasy setting. The size is absurd, but that’s what it’s all about and that’s why it’s interesting in the first place. No some answers:\nUnderground caverns/tunnels\nGet yourself some underground cave system with some tasty mushrooms and some solid building material to mine. If you’d go crazy you could use your poo to fertilize the mushrooms and build underground farms etc. but I’d rather like to keep the details out of here. Just dig down, eat mushroom and be happy. One could also dispose corps into catacombs. The risk of plagues a heavy disease is still high, but on the other hand side a city of that size probably won’t be a nice place in the first place. Constant mining may also lead to parts of the city to collapse into the depths below, requiring the city to be constantly being renewed.", "222" ], [ "Apocalypse To-Do List\nNote : I've read some questions dealing with post-apocalyptic scenarios ( fuel and what next after apocalypse? ) and one on a apocalyptic situation but Im more interested in what to do immediately while there is a zombie Apocalypse going on. I dont want <PERSON> spending his entire life at sea or anything.\nBackground : A zombie apocalypse has just happened, due to the military and their scientists - but there are already a lot of zombies. <PERSON> and 3 friends (they're all about 20-23 years of age and unmarried) are all zombie fanatics and have made all sorts of plans on what to do when there is a zombie Apocalypse. (Also, this is taking place in a average town in America) So while they do panic, they manage to calm down and think of what to do.\nPeople : <PERSON> and his friends are average white males, who have played pretty much every zombie game and have made sure to memorize where the nearest gas-station,market,gun store etc is. They like sports (though zombie games is #1), and <PERSON> likes working out.", "934" ], [ "Lets ignore their family for this question.\nZombies : Most of them are the shambling type, though a few (like 3 out of 10) are the running type.\nQuestion : What is the best plan of action for <PERSON> and his friends ? Lets say that everyone was at <PERSON>'s house watching a zombie movie, and <PERSON> has fully fuelled minivan and some baseball bats.\nThe plan of action should answer questions like these -\n* 1) What ranged weapons are the best ? A answer for short-ranged ones has already been given, but even zombie fanatics don't stock up on maces. And baseball bats against a mob of zombies is slightly ineffective. Should they go for rifles or shotguns ? Or should they use pistols ?\n* 2) Where should they go first ? Pretty much every zombie-plan includes going to the gun-store, and it will be hard raiding a shop with others people trying to grab whatever they can.\n* 3) Where should they camp ? Holing up in a place with other people will be troublesome (especially if they're panicking and ready to shoot others if they think someone is infected)\n* 4) What food should they get ? <PERSON> has some canned food, but between the 4 of them, it will run out quickly. Where should he go to loot for food, and what should he take.\n* 5) How should they deal with other people ? It's conceivable that someone may beg to join them, only to later betray them or leave them as bait. Or if someone joins them, but has been bitten (and is hiding it).\nAlso, is it possible for them to have some sort of makeshift armour that protects against zombie bites ? That is, it covers arms and legs.", "164" ], [ "Of Nazis and Zombies\nIt's 1942 and the Nazis finally perfected a weapon which will change the war : Die Früherwaffe\nThis weapon basicly is some kind of mathematical-magic-powered weapon that allows you to cast spells. It's easy to use and was designed to be used by pretty much any member of the German army. The only requirement is to have a special mark that acts as a unique identifier that unlock the weapon.\nMost spells mimic the effects of modern gear, they can work as radars, GPS, guns, smoke grenades, medkit. These spells are cool but they dont offer much innovation and cant be considered a serious advantage in the war.\nBut the most wicked Nazi's scientist designed a very complex spell that seems to have a lot of potential. You guessed it, a zombification spell.\nBefore asking anything let me tell you how it works.\nFrüherwaffen buchstabieren : Zombieshaffung\nUsage :\n1. Load the \"Zombieshaffung\" cartridge into your Frühergewehr.\n2. Aim toward a dead body at a maximum range of 100 meters\n3. Congratulations ! You just gave that body a new chance to serve the Reich !\nCommanding your Zombie :\nYour zombie will only respond to orders he has been taught.", "523" ], [ "To provide a combat-ready solution, the Reich pre-programmed your zombie with a set of basic orders. Here is a non-exhaustive list of pre-programmed orders :\nGO TO, CARRY, FOLLOW, FETCH, WALK, RUN, STAY, SLEEP, LOOK OUT FOR, ATTACK, PROTECT, EAT, DIE, OBEY TO, USE, ATTACH\nZombies will obey to identified German soldiers and consider all other hot-blooded creatures as hostiles if ordered to ATTACK / PROTECT a zone. You can tell your zombie to only execute orders given by a defined identified subject (or group) using the OBEY TO command.\nIf you have any issue with your zombie or need to have a new order programmed, ask a Früherscientist.\nSummary on Zombie metabolism :\nZombies don't need any food, the EAT command was mainly given to have them take care of waste (Bodies or other) and for your enjoyment.\nThe only way to kill a zombie is to destroy the mark that was branded on the body as part of the creation process. Any body part severed from the mark will lose all animation. We therefore recommend to put the mark somewhere on the torso or head.\nA reattached bodypart (even if it was not the original one) will start functioning again. We highly encourage you to customize and repair your zombie by changing body parts regularly. To do that, simply ask your zombie to do so. If your zombie is unable to perform the task, you may do it yourself by roughly reconnecting bodyparts using staples, wire or rope. The zombie will take care of the rest.\nQ&A\n- Do zombies feel pain ?\nIt's irrelevant.\n- What are zombie's vulnerabilities and resistances ?\nZombies are particularly vulnerable to fire and are resistant against crushing, shrapnel, toxins and small to medium caliber bullets.\nConsidering all I've written, here are my questions :\n* Can this weapon REALLY change the war (As in the German winning) ?\n* How should these zombies be used by the Germans forces ?\n* Reasons why German troops would find using that weapon ethical.", "802" ], [ "Practical aspects: It seems to be agreed that the jar + Burning Plant idea is really difficult to be set up.\nWhy not separate the combustible from the activator? I will take a few concrete examples, but feel free to replace them with items from your world:\n* Matches are the activators (could be a chemical product stored in glass)\n* Coal is the combustible (could be an GMO)\nThis could help you to have a system of coins and bills or something, since the two products are used together to burn things With this principle you also ease trades (matches are lights, and it is easy to spare them, and to give change)\nMarket aspect:\nA currency has a value, this value is based on another product: for example € with gold (If you have several countries and currencies it’s more based on the exchange rate and interest rate) So your currency should have a reference, something valuable which should not fluctuate too much.\nBut here you want to use a consumable as currency which means that its value will depend on the value of your chosen “valuable product” and the amount of your currency available (remaining matches in your country for example).\nHow do people earn these matches ? Is it an universal income ? How many matches are consumed by people per year? How many matches do you need for survive per year? How many matches are you earning each year? How much is it fluctuating during the year? (consuming/earning rate)\nThose questions will help you determine your currency fluctuation, but also to determine the real impact on the market (inflation and deflation)\nYou can imagine that the value of coal will decrease in summer, and dramatically increase in winter. I would suggest to have durable matches to always have a stable amount of matches on the market: the amount of matches/coal should drop significantly in winter, if a match has a short lifetime then in spring there will be no resources left.\nThis is a real problem: if one match is worth one bread in summer, one match could equal ten breads in winter.", "130" ], [ "How do you really determine the value of your currency ? Keeping that in mind people will probably prefer to sell in summer and to buy in summer.\nSeparating the activator from the combustible (and maybe the combustive?) could introduce some new concepts: - You waste matches when failing the strike, and as matches are your daily money and the value is evolving, wasting a match in winter means losing a lot - People always want to optimize things, they will develop techniques intending to limit the waste of coal/match; - People will take risk in selling all their matches during winter and buying a lot in summer. - Poor people will buy the bare necessities of life selling there last remaining matches.\nHave you read the stormlight archive by <PERSON>? There are some similarities as they use glowing spheres as main currency, meaning they use it for light as well as money. These aren’t really combustible as they are rechargeable but the Wkipage could give you ideas https://en.wikipedia.org/wiki/The_Way_of_Kings\nEDIT: Hope this is better", "130" ] ]

[ 690, 3966, 10051, 3015, 2012, 1391, 10087, 4624, 5276, 9860, 4902, 4568, 7011, 9585, 10374, 10496, 8717, 550, 810, 1339, 6278, 3876, 856, 3705, 2840, 9966, 1972, 1013, 1471, 5521, 9628, 3181, 4674, 4385, 3374, 4665, 2151, 5722, 1744, 10217, 10922, 10932, 7498, 1506, 535, 654, 5378, 6339, 9399, 2924, 6020, 3493, 8365, 3466, 936, 8971, 7095, 7883, 8325, 10134, 699, 7511, 8984, 683, 2623, 5685, 1093, 5186, 1815, 8200 ]

[ [ "The word \"humanitarian aid\" refers to the provision of humanitarian assistance to those in need. Cyborgs, androids, robots, aliens, mutants, and other human-like beings are some examples. Science fiction, fantasy, and horror literature and movies frequently include these monsters as main characters. Depending on the scenario, they may be presented as friendly or aggressive.\nThemes of humanity and morality are frequently explored through the usage of humanoid creatures. They can act as substitutes for actual people, helping viewers to learn more about challenging subjects like prejudice and discrimination, artificial intelligence, and the conflict between good and evil. They can also offer a distinctive viewpoint on the human experience by delving into issues like identity, connections, and what it means to be human.\nRobots that mirror the appearance and capabilities of the human body are called humanoid robots. They normally have a head, a torso, two legs, and two arms. They are made to interact with people and their surroundings in a way that is comparable to how people do. It's a great way to meet new people.", "481" ], [ "Humanoid robots' technology is continually developing, and they are becoming more sophisticated and capable.Robots that resemble humans are frequently utilised in business, science, and entertainment.They can help with jobs like welding, painting, and product assembly at industrial facilities. To test theories and hypotheses or to help researchers with challenging tasks, they can also be employed in research labs. They have also gained popularity in the entertainment industry, showing up in movies, TV shows, and video games. because of technology.\nFor a number of reasons, humanoid robots are becoming more and more significant in contemporary technology. They can execute jobs that are too complex or dangerous for people, to start with. This covers activities like cutting and welding in risky situations as well as conducting search and rescue missions there. The second is that they can help the elderly or those with impairments. This may entail assisting with routine tasks like cooking, cleaning, and shopping. Finally, they can be utilised to offer emotional support and company, which can be especially helpful for those who are lonely or may be depressed. Last but not least, they can be employed to supply entertainment in the shape of robotic pets or interactive games.", "481" ], [ "Having a strong understanding of mathematics is crucial for navigating our increasingly interconnected and data-driven world. The capacity for logical reasoning, mathematical reasoning, and an understanding of numerical relationships is becoming more and more crucial in virtually every sector and career. Hence, being literate in mathematics has become a valuable ability for citizens to acquire.\nThere are several advantages to being literate in mathematics. Mathematical literacy is an important skill for people of all ages, as it helps with everything from being able to understand data and analyze patterns to creating and evaluating financial strategies. Making better judgments in daily life—whether they involve money, health, or public policy—can be facilitated by developing this talent.", "256" ], [ "Also, it can aid in closing the knowledge gap between individuals who are conversant in mathematical ideas and those who are not as proficient in them.\nAlso, mathematical literacy is becoming more and more crucial in the job because it's necessary to have a solid grasp of fundamental math in order to read graphs, analyze data, and come up with innovative solutions to issues. People could lose out if they lack certain skills on chances for growth and development.\nA ranking of the mathematically literate nations and on how it has benefited them\n-Japan: Due in part to a heavy emphasis on math education, Japanese Students routinely perform in the high echelon of international math assessments. As a result, Japan is now a global leader in engineering, robotics, and technology.\n-South Korea: Because to the country's concentration on math education, South Korean students consistently achieve among the highest marks on international math exams, and the nation is now a leader in science and technology.\n-Singapore: Singapore has made considerable investments to guarantee that its pupils are knowledgeable in maths. This has enabled the nation to pursue scientific research and establish itself as a global leader in financial technology.\n-Finland: Finland places a lot of focus on math and science education, which has helped it become one of the top engineering and technologically advanced nations.\n-India: Due to increased investment in math and science education, India has seen a boom in technology companies. Math and science are highly valued in India.\n-China: China has made significant investments in math and science education, which has resulted in outstanding advancements in the fields of robotics and artificial intelligence.\nSome nations have achieved global leadership status in science and technology by making investments in math literacy and putting more focus on math education.\nIn conclusion, being literate in math is an useful ability in today's complex world. Understanding mathematics is crucial for a variety of reasons, including decision-making and gaining an edge in the labor market.", "1006" ], [ "Technology and imaginary world building have had significant impacts on each other. While the former has made the latter more accessible and immersive, the latter has inspired new technologies and pushed the boundaries of what is possible. The ways in which world building has influenced technological advancement include:\nInspiration for new technologies\nThe creation of imaginary worlds has often served as inspiration for the development of new technologies. Imaginary worlds have helped in the following areas of technological advancement:\nRobotics\nMany science fiction works have featured robots, inspiring researchers to develop real-life robotics technology. Robots have the potential to revolutionize industries such as healthcare and manufacturing.\nAugmented and virtual reality\nImaginary worlds have also inspired the development of augmented and virtual reality technologies.", "256" ], [ "These technologies can be used for training, education, and entertainment purposes.\nSpace exploration\nImaginary worlds set in space have played a role in inspiring real-world space exploration efforts. Works of science fiction have often imagined life on other planets, leading to research in fields such as astrobiology.\nPushing the boundaries of what is possible\nImaginary world building has also played a role in pushing the boundaries of what is technologically possible, especially in the aspect of cinematography.\nThe need to create believable imaginary worlds has benefitted special effects technology. From the use of miniatures in the original Star Wars films to the use of CGI in modern films, special effects technology has advanced rapidly in response to the demands of the genre.\nMoreso, the creation of imaginary worlds has also driven advancements in computer processing power. High-end graphics cards and processors have allowed creators to build ever-more complex and detailed environments, bringing imaginary worlds to life in unprecedented detail.\nFinally, imaginary world building has led to improved storytelling technology. From interactive narratives in video games to the use of AI in creating dynamic and personalized stories, the genre has inspired creators to find new and innovative ways to tell stories.\nConclusion\nAs the world building genre continues to evolve, we can expect to see even more exciting advancements in technology inspired by the worlds of our imagination.", "256" ], [ "Animals and plants use many strategies to gather nourishment. Animals hunt and obtain food from their surroundings, whereas plants produce their own food through photosynthesis. The processes of photosynthesis in plants and how animals look for food will be covered in this article.\nUsing a process known as photosynthesis, which calls on sunlight, water, and carbon dioxide, plants are able to produce their own sustenance. Chlorophyll, a chemical present in organisms that can synthesize organic compounds from light energy, aids in this process. Plants are given the energy and nutrients they require to develop and survive through this process.\nWhat really is Photosynthesis\nPlants and other photosynthetic creatures employ the process of photosynthesis to transform sunlight into energy. Chlorophyll is employed in this process to absorb sunlight and transform it into organic chemicals that the organism uses for energy and growth. It supports the entire environment and is a crucial link in the food chain.\nThe importance of Photosynthesis\nFor plants and other photosynthetic organisms, photosynthesis is a crucial activity because it gives them the energy and nutrients they need to grow. Also, as it aids in removing carbon dioxide from the atmosphere and thereby lessens global warming, it is crucial for the global carbon cycle. Hence, photosynthesis is essential to maintaining the equilibrium of the Earth's environment.\nWho really came up with this\nAccording to scientists, <PERSON> discovered photosynthesis in the 1600s. He observed that although the amount of soil appeared to remain constant as a plant grew in it, the plant had expanded dramatically. This sparked additional investigation into photosynthesis, and ultimately it was learned that plants utilize sunlight to produce their own sustenance.", "731" ], [ "Subsequently, researchers were able to pinpoint the elements required for photosynthesis, including carbon dioxide and water, as well as the function of chlorophyll in absorbing sunlight.\nSo how do animals take their own food\nAnimals either hunt or scavenge for food. Tracking and pursuing prey while employing physical or behavioral adaptations to bring it down are all part of hunting. Searching for food that has been left behind by other animals or released from their own bodies is known as scavenging (such as feces).\nEnergy is transferred from one organism to another in food chains. Producers, like plants, which can manufacture their own food through photosynthesis, are at the bottom of the food chain. Primary consumers, like herbivores, who are unable to produce their own food and must rely on plants for sustenance, then consume producers. Secondary consumers, such as carnivores who are higher on the food chain, subsequently eat these primary consumers. They are dependent on other animals for food. Energy is transferred in this manner up the food chain until it reaches the apex predators. The top predators, such as bears and lions, are typically at the top of the food chain and must eat other animals in order to survive. As a result, the food chain is a network of interconnected species that rely on one another to survive.\nIn conclusion\nBoth plants and animals require sustenance in order to survive. Animals must hunt and obtain food from their surroundings, but plants employ photosynthesis to produce their own sustenance. Both processes are fundamental to maintaining the delicate balance of nature in our world and significantly rely on adaptation and evolution to be effective.", "445" ], [ "In the cooperative board game \"Pandemic,\" players assume the roles of several specialists entrusted with containing and getting rid of diseases all throughout the world. Players must cooperate to stop the spread of diseases, develop treatments, and eventually preserve the world in this globe map-based game. Each participant has a distinct function and can take advantage of certain special powers. For instance, the doctor can eliminate numerous sickness cubes from a city with a single action whereas the scientist can find a treatment with fewer cards.\nThe randomness of \"Pandemic\" is one of its distinctive features. The towns that are infected with diseases and the severity of the epidemic are determined by the cards that players draw at the start of each turn. Because players must continually adjust to new obstacles and collaborate to find answers, the game's element of chance keeps things interesting and fresh.\nTop-quality effort went into \"Pandemic's\" graphics and layout. The game's playing surface is a globe with vibrant, colorful graphics that are both aesthetically pleasing and useful. The player cards show in-depth depictions of each specialist's distinct skills, and the game components are sturdy and well-made. The game's overall polished and professional appearance enhances the immersive experience.\nEvery time I've played \"Pandemic\" with friends and family, it's been a blast. The game's cooperative design encourages cooperation and communication, which results in an enjoyable and interesting experience.", "699" ], [ "Requiring players to use strategy and adjust to shifting conditions stops it from getting boring, makes it difficult, and Fresh.\nEach playtime of the game is distinct since it is randomly generated, offering players fresh obstacles and possibilities. The game includes various different jobs and levels of difficulties that are joined to make extraordinary game varieties. Consequently, there are in every case new ongoing interaction mechanics and strategies to explore different\nThe game powers members to cooperate as opposed to rival each other, which encourages joint effort and correspondence. Also, the game's randomization keeps it intriguing and fresh, preventing it from being boring. The game's replay ability is another plus because there are constantly fresh obstacles to overcome and tactics to experiment with.\nIt is a good idea to have a backup plan in case of an emergency. The game is difficult, requiring players to use strategy and adjust to shifting conditions. Some players can find this scary, especially beginners to board games. Also, because of the cooperative aspect of the game, it can be unpleasant when a single player makes a mistake that badly affects the entire team.\nAlthough \"Pandemic\" is meant to be played as a group, it can also be played alone. The game's solitary play guidelines are the same as its multiplayer guidelines. Yet when you play alone, you lose the cooperative aspect of the game, which depends on communication and teamwork. Also, playing alone may be less enjoyable because you have no one to bounce ideas off of or experience the game with.", "853" ], [ "Information is converted into a code that can only be understood by the intended receiver through the use of encryption. It is frequently utilized to safeguard privacy, protect data, and secure conversations. The function of encryption and the many kinds of encryption techniques will be examined in this article.\nIn order for information or communications to be encrypted, they must first be converted into ciphertext, an unintelligible form. A hidden piece of information known as a key and an algorithm are used to perform this transformation. Only those who possess the proper key can decrypt the message after it has been locked (encrypted) using the key.\nIt's crucial to remember that encryption does not ensure total security. There are various encryption methods that can be utilized, and they can provide differing levels of protection.", "256" ], [ "Asymmetric encryption algorithms, on the other hand, utilize different keys for encryption and decryption while symmetric encryption methods use the same key for both.\nOther encryption methods are also available, including Transport Layer Security (TLS). The secure communication between two or more parties is guaranteed by this protocol. A popular security protocol that encrypts data delivered over the internet is HTTPS.\nData and communication security can be improved via encryption. It functions by converting data into an unintelligible format that can only be decoded with a secret key. There are many different encryption methods and protocols out now, each with varying degrees of security. Individuals and organizations can guarantee the security of their data and the privacy of their conversations by implementing the appropriate encryption techniques.\nThe most recent encryption techniques and protocols must also be kept up to date for corporations. In order to protect data from hostile actors, it is crucial to utilize the most secure encryption algorithms available because new threats are always developing.\nThe benefits of encryption include:\n- Preventing unauthorized access to data\n- Assisting in maintaining the security and privacy of people and organizations\n- It can be put into practice rather fast.\nThe following are the drawbacks of encryption:\n- High implementation costs\n- Difficulty in handling many keys\n- Possibility of using old protocols or insecure encryption, leaving data open to attack", "256" ], [ "Aliens are a well-liked component of world building and may bring something special to any narrative. Aliens can be human-like or insect-like and have a wide range of varied traits and skills. Aliens might have unusual civilizations, habits, and beliefs in addition to their alien physical characteristics, which could make for intriguing story points or conflicts. They can also be used to investigate concepts like ethics, technology, and the unknowable. Aliens can serve as antagonists, friends, or even protagonists, depending on their species and the plot.\nThe alien environment is probably very different from what we are accustomed to on Earth. It might be a strange and exotic environment with foreign landscapes, unusual and exotic species, and strange and exotic plants and animals. There may be unknown galaxies and stars in the sky, as well as unique geological formations and foreign topography, on the earth. We may encounter weather patterns and temperatures that are significantly dissimilar from our usual ones in the environment.", "481" ], [ "The light may be different from what we're used to, and the air may smell unusual. The alien world will ultimately be a mysterious and amazing location with a unique atmosphere that we have never before encountered.\nUnidentified flying objects, or UFOs, are typically thought to be alien objects that cannot be identified. The assumption that aliens are to blame for the occurrence of UFOs is not supported by scientific data, yet the widely accepted idea of alien visitation has permeated many people's views. Theorists have suggested different hypotheses for the purpose of UFOs, ranging from government experiments to interdimensional entities. However, there is no concrete evidence that extraterrestrials are behind the development of UFOs.\nWhile the notion of a world where aliens live is intriguing, it also presents a special set of difficulties. The effects of such a development on the environment, the economy, and the social structure of a society must be taken into account. The ethical ramifications of introducing a new species into an established ecosystem must also be taken into account. But, with the correct planning, a world inhabited by aliens may develop into a thriving and diversified population, providing a chance to investigate novel relationships, cultures, and technological advancements.", "481" ], [ "One of the world's biggest and most famous deserts, the Sahara Desert spans North Africa and is around 3.6 million square miles in size. The Sahara has always been a harsh and brutal environment. Still, in the coming decades, climate change's effects are anticipated to substantially impact the desert's size.\nRising temperatures, sea levels, and more frequent and severe extreme weather events are just a few of the changes that climate change is bringing about to the Earth's climate system. The Sahara Desert is no exception to how these changes affect ecosystems and biodiversity worldwide.\nIncreased desertification is one of the principal effects of climate change on the Sahara. It becomes more difficult for plants and animals to thrive as once-rich terrain becomes increasingly arid through the process known as desertification. Managing natural resources, land use patterns, and climate change are just a few factors that frequently influence this process.", "867" ], [ "In the case of the Sahara, desertification is anticipated to be primarily driven by climate change, resulting in increased temperatures, less precipitation, and more frequent droughts.\nAs the Sahara grows drier, the size of the desert will increase, decreasing the amount of land accessible for farming, grazing, and habitation. Significant social, economic, and environmental effects could result from this, such as a rise in food insecurity, a decline in biodiversity, and community relocation.\nOther effects of climate change on the Sahara are anticipated besides desertification. These effects include changes in temperature and precipitation patterns and a rise in the frequency and severity of extreme weather events like sandstorms and floods.\nOverall, the Sahara is projected to experience severe and varied effects from climate change. Although it is difficult to foresee exactly how the desert will evolve over the next few decades, it is obvious that immediate action is required to reduce the effects of climate change and save the local population and ecosystems. This will necessitate various actions, such as lowering greenhouse gas emissions, encouraging sustainable land use, and helping local residents adjust to the changing environment. By acting now, we can ensure that the Sahara, as well as the people and wildlife that call it home, have a sustainable and prosperous future.", "481" ] ]

[ 983, 8030, 1758, 8954, 6484, 3909, 3691, 7235, 2279, 6498, 6165, 9999, 752, 3693, 1998, 8608, 8359, 7362, 7679, 7882, 7121, 4491, 1727, 8926, 3601, 5809, 5797, 2460, 3588, 1134, 4618, 2048, 617, 1916, 10971, 9619, 4587, 2405, 7299, 5500, 1205, 10998, 11040, 9353, 761, 9855, 1034, 10725, 724, 2648, 858, 6670, 9320, 9903, 9254, 4646, 1260, 3849, 289, 5315, 8, 1672, 4822, 4849, 6389, 10817, 7692, 137, 6516, 7810 ]

[ [ "Theory of Complex Spectra, Applying Slater-Condon Rules\n<PERSON> and <PERSON> in Physical Review 1932, Vol. 42, pg. 167, separate the two $^2$D's of $d^3$. On page 173 (pg 7 of the PDF) of this article they determine the matrix of the electrostatic energy in eqn.", "469" ], [ "3.3 as: $$\\begin{array}{ccc} - &a & b \\ a & 3F_0+7F_2+63F_4 & 3(21)^{1/2}(F_2-5F_4) \\ b & 3(21)^{1/2}(F_2-5F_4) & 3F_0+3F_2-57F_4 \\ \\end{array}$$\nI'm trying to figure out how they actually determine this matrix. How do they do it?\nHere is what I understand:\nThis matrix comes from a description of the two terms, $$^2D^a_{2,1/2} = 1/2 [-A+B-C+E]$$ $$^2D^b_{2,1/2} = (84)^{-1/2}[-5A-3B-C+4D-3E-2(6)^{1/2}F]$$\nwhere $A,B,C,D,E,F$ are zero-order states of $d^3$ which are $$\\begin{array}{cccc} A &\\mathcal{A}u_1(2^+)u_2(2^-)u_3(-2^+) & B &\\mathcal{A}u_1(2^+)u_2(1^+)u_3(-1^-) \\ C &\\mathcal{A}u_1(2^+)u_2(1^-)u_3(-1^+) & D &\\mathcal{A}u_1(2^-)u_2(1^+)u_3(-1^+) \\ E &\\mathcal{A}u_1(2^+)u_2(0^+)u_3(0^-) & F &\\mathcal{A}u_1(1^+)u_2(1^-)u_3(0^+) \\ \\end{array}$$\nIn this notation $u_i(a^j)$ indicates the one-electron central field eigenfunction for electron $i$ with the $j^{th}$ set of numbers $n^il^im_l^im_s^i$. $\\mathcal{A}$ represents the antisymmetrizing operator $(N!)^{-1/2}\\sum_P (-1)^p P$.\nWe can say that $(ab|1/r_{12}|cd)$ depends, in part, on $\\sum_{k=0}^\\infty c^k (l^a m_l^a, l^c m_l^c) c^k(l^dm_l^d,l^bm_l^b)$\nThere are tables of these values already determined, notably as $a^k$ and $b^k$, which can be used to evaluate the Coulomb and exchange integrals for $k=0,2,4$.\n<PERSON> then extended <PERSON>'s method to determine the non-diagonal matrix elements in a paper (Physical Review, 1930, Vol. 36, pg. 1121) for separating multiplets of the same kind, as we have in our case.\nIn case you are confused by the notation, $J(a,b)=\\sum a^k$ and $K(a,b)=\\sum b^k$ and $a^k(l^am_l^a,l^bm_l^b)=c^k(l^am_l^a,l^am_l^a)c^k(l^bm_l^b,l^bm_l^b)$ and $b^k(l^am_l^a,l^b m_l^b) = [c^k(l^am_l^a,l^bm_l^b)]^2$.", "490" ], [ "Solving Shroedinger Equation for the electronic energies of the Molecular Ion Hydrogen H2+ in the Elliptic coordinate system\nElectronic Energies of Molecular Ion Hydrogen $H_2^{+}$\n$r_1$ is the distance between the proton $1$ and the electron.\n$r_2$ is the distance between the proton $2$ and the electron.\n$R$ is the distance between the two protons, fixed parameter in Born Oppenheimer approximation.\n<PERSON>'s Equation:\n$$ \\hat{H} \\Psi = E_{el} \\Psi $$\n$$ -\\frac{{\\hbar}^2}{2 m_e} \\Delta \\Psi -\\frac{e^2}{4 \\pi \\varepsilon_0} (\\frac{1}{r_1}+\\frac{1}{r_2})\\Psi = E_{el} \\Psi $$\nAtomic Units:\n$$ a_0=\\frac{4 \\pi \\varepsilon_0 \\hbar^2}{m_e e^2} = 0.5291 *10^{-10} m $$\n$$ E_h=\\frac{\\hbar^2}{m_e a_0^2}=27.21 eV $$\n$$ \\Delta \\Psi + \\frac{2}{a_0}(\\frac{1}{r_1}+\\frac{1}{r_2})\\Psi=-2 \\frac{E_{el}}{E_h a_0^2} \\Psi $$\nWe introduce the adimentional parameters $ r= \\frac{R}{a_0} $ and $ \\varepsilon = \\frac{E_{el}}{E_h} $\nElliptic coordinate system:\n$ \\xi = \\frac{r_1 + r_2}{R} $ , $ \\eta=\\frac{r_1 - r_2}{R} $ and $ \\phi $ is the angle between the position vector of the electron and the $xy$ plane.", "374" ], [ "Why is the Beta-Decay of a Neutron asymmetric?\nThe <PERSON>-experiment, which originally showed the parity violation of Beta-Decay experimentally, is often used to give an intuitive explanation for the asymmetry of the decay:\n$${}^{60}{27}\\text{Co} \\rightarrow {}^{60}{28}\\text{Ni}^* + e^- + \\bar{\\nu}_e$$\nCobalt has $I=+5$, and nickel has $I=+4$ . Due to conservation of angular momentum the electron and the antineutrino both have $S=+1/2$, i.e. in the same direction as the cobalt. The requirement for right-handedness of the antineutrino (which we assume as given for now), gives then the asymmetry in the decay.\nHowever, when I look at the decay of the free neutron,\n$$\\mathrm{n}\\rightarrow\\mathrm{p}+\\mathrm{e}^-+\\bar{\\nu}_e$$\nI find that the spin of the neutron and proton are equal ($=1/2$). The total angular momentum can be conserved by aligning the spins of the leptons opposite to each other or, I guess, by adding angular momentum to the leptons.\nMy problem is here, that it is not straightforward to see the asymmetry in this case by just looking at the momentum conservation. It seems that the information of the polarization of the neutron is somehow not conveyed to the leptons: The only requirement is that their $S+L=0$, which allows to arrange the spins of the leptons independently of the neutron.", "617" ], [ "One could also take e.g. the decay of\n$${}^{8}{3}\\text{Li} \\rightarrow {}^{8}{4}\\text{Be}^* + e^- + \\bar{\\nu}_e.$$\nHere <PERSON> has $I=2$ and Be $I=2$, which poses the same difficulty for me.\nIs it possible to understand the last cases simply based conservation of angular momentum and the forbidden left-handedness of the antineutrino (similar to the case of cobalt-60)?\nEdit:\nThank you very much for the extensive comment!\nI found the following diagram in a diploma thesis about the neutron beta decay :\n(From https://www.physi.uni-heidelberg.de/Publications/dipl_mund.pdf )\nApparently you can classify the decays on whether they decay into a singlet or triplet of the leptons (\"Zerfall\" means \"decay\" in German). You can see that there is a channel, which is actually sensitive to the original polarization of the neutron: In the last one, the proton spin flips, but it is always opposite to the neutron, the leptons align with the neutron. The beta-decay of the neutron seems to be a mixture of all three. This would imply that the first channel (\"Fermi\") is actually symmetric.\nI think this is also the reason, why someone talks about the asymmetry being \"full\" in the <PERSON> experiment, since it fully decays in an asymmetric channel. Cases like the neutron might be actually less asymmetric than Co60.", "617" ], [ "Conservation of Momentum Paradox Thought-Experiment (Please Explain)\nThe Device: Imagine a physical system involving two circular rings of distinct inner and outer radii, but equal in inertia. The smaller ring is superimposed inside the inner radius of the larger ring. These two rings have negligible thickness and are allowed to freely rotate about an axis going through their center of mass, lying on the horizontal x-y plane. The axis of rotation is orthogonal to the face of the rings.\nNow, imagine a long rod along the z-axis attached to both rings, connecting them together by acting as the \"spine\" of this ring-system. This rod is attached symmetrically through their center of masses along the z-axis. When the rod moves along the z-axis, it moves both rings translationally along with it. The rings are still allowed to freely rotate as mentioned previously, but their faces can no longer rotate because of the rod.\nOn the other end of the rod, some distance away, is attached a large square plate whose length or width (being the same) cannot be less than the outer radius of the largest ring on the other end of the rod; it is at least slightly longer. Both faces of the two-ring system and the square plate are orthogonal.\nThe Phenomenon: Imagine that potential energy is introduced into the system. After the full amount of potential energy is stored into the system, we will call this system a close-system for energy whose total energy will be equal to the stored potential energy.\nThe energy is stored by, e.g., two loaded mechanical box springs. One is placed sitting tangent outside of the smaller inner ring to the right and the other is placed tangent outside of the larger ring to the left. Suppose that each ring has at least one groove or a tiny paddle that the springs are sitting on.", "782" ], [ "There are two balls sitting on the other end of each spring of same mass.\nNow the system is given energy by compressing the springs together, pushing the ball down closer the groove of each ring. Then, in an instant, the springs are released turning all the potential energy into kinetic energy. (The springs had negligible mass and no longer become relevant once released).\nAll net forces and torques in this system during the release were zero, e.g., the force on the ball was the same yet opposite in direction to the tangential force on the ring. The torques on both rings were also the same but opposing in direction. Their new angular momentum is the same in magnitude but are anti-parallel because they have the same inertias, consistant with <PERSON>'s Laws. Energy and Angular Momentum are both conserved in this thought-experiment\nHas Linear Momentum Been Conserved?\nThe whole two-ring, rod and plate system is NOT moving translationally because no force had acted through it's center of mass.\nUp to this point, in terms of linear momentum, only the balls carry linear momentum. The whole system, if you include the balls is net positive for linear momentum, which is perplexing considering that it started with zero linear momentum before the energy release. This was true for angular momentum--it started with zero and ended with net zero, but not linear momentum. Now let us continue this thought-experiment because the balls are moving in space right now.\nTo show what this means fully, the balls are headed for a collision course to the square plate at the end of the rod. Let's suppose that they make an \"inelastic collision\" with the plate, such that linear momentum is conserved. The balls are now stuck to the plate and all their momentum has been transferred to the entire mass of the contraption. The entire system is now slowly moving forward with net linear momentum!\nPlease tell me what went wrong in this experiment", "782" ], [ "Transforming Observables, Missunderstanding <PERSON>, Intro. to QM, or a Possible Error\nIn <PERSON>' Intro. to QM 3rd, Sec. 6.2, transforming an observable $Q$ by the translation operator $T$ is found to be $$ Q' = T^\\dagger Q\\ T $$ the same for the parity operator $\\Pi$ instead of $T$ we have $Q' = \\Pi^\\dagger Q\\ \\Pi$.\nBut in other texts, e.g., <PERSON>, QM, 2nd ed, Vol. I, Complements of chapter VI, Complement B$_{VI}$, 5. Rotation of observables, and also in other questions here and here the transformation on the observable $A$ by a unitary transformation $U$ should be $$ A' = UA\\ U^\\dagger $$ where $U$, as I understand, should be an active transformation, as $T$ above and I expected that the two equations should be the same.", "346" ], [ "But it seems that the two definitions are not equivalent, or is there any mistake?\nADDED\n<PERSON> Definition:\nThe transformed operator $\\hat Q'$ is defined to be the operator that gives the same expectation value in the untranslated state $\\psi$ as does the operator $\\hat Q$ in the translated state $\\psi'$ $$ \\langle\\psi'|\\hat Q|\\psi'\\rangle = \\langle \\psi | \\hat Q' |\\psi \\rangle $$ There are two ways to calculate the effect of a translation on an expectation value. One could actually shift the wave function over some distance (this is called an active transformation) or one could leave the wave function where it was and shift the origin of our coordinate system by the same amount in the opposite direction (a passive transformation). The operator $\\hat Q'$ is the operator in this shifted coordinate system.\nUsing Eq. 6.1, $$ \\langle\\psi|T^\\dagger\\hat Q\\ \\hat T|\\psi\\rangle = \\langle \\psi | \\hat Q' |\\psi \\rangle $$\n<PERSON> Definition:\nLet us assume the system to be in the eigenstate $|u_n\\rangle$ of $A$: the device for measuring $A$ in this system will give the result $a_n$ without fail. But just before performing the measurement, we apply a rotation $\\scr R$ to the physical system and, simultaneously, to the measurement device; their relative positions are unchanged. Consequently, if the observable $A$ which we are considering describes a physical quantity attached only to the system which we have rotated (that is, independent of other systems or devices which we have not rotated), then, in its new position, the measurement device will still give the same result $a_n$ without fail. Now, after rotation, the device, by definition, measures $A'$, and the system is in the state: $$ |u_n'\\rangle = R|u_n\\rangle $$ We must therefore have: $$ A|u_n\\rangle = a_n|u_n\\rangle \\implies A'|u_n'\\rangle = a_n|u_n'\\rangle $$ that is: $$ R^\\dagger A' R |u_n\\rangle = a_n|u_n\\rangle $$\nNote that $\\scr R$ is the rotation the physical 3-dimensional space and $R$ is the its representative operator in the Hilbert space.", "669" ], [ "Quantum Indeterminacy is Key to the Arrow of Time\nThere is no machinery to explain the randomness (as Mr. <PERSON> answered from <PERSON>), but maybe a connection to other phenomena can help.\nI'm going to go out on a limb here, because answers in this forum are supposed to be from established science. But I think I can make a case for an important explanation that I think follows logically, even if I haven't seen in the literature.\nI think we can make the case that there is a fundamental connection between quantum randomness and the arrow of time. Here are the parts of that idea:\nSpecial Relativity and Time Reversal\nWe know from Special Relativity that all inertial frames are equally valid, that the laws of physics in one (non-accelerating) frame are exactly the same as in any other. This principle also applies to frames of reference where time is reversed.", "562" ], [ "In fact the <PERSON>-Stueckelberg interpretation of antimatter is the idea that antimatter is matter going backwards in time.\nTime Reversal and Entropy\nBut we know from the second law of thermodynamics that entropy either increases or stays the same, but it doesn't decrease (at least not on the macro scale). So one principle says that the laws of physics are the same under time reversal (actually something called CPT) but another says that entropy increases are irreversible.\nThis contradiction is called Loschmidt's Paradox.\nTime Reversal and Quantum Choices\nNow here's the idea that I came up with. It's probably already out there somewhere, I've looked and haven't seen it though. If someone knows where this has been developed (if it has) I would very much like a reference.\nIf a sequence of events is deterministic (one with no random quantum choices) then the time reversal of that sequence must also be deterministic, and the reversal of that sequence would always return the system to its original state.\nBut if a sequence of events involves random quantum choices, then the reversal of that sequence also involves random quantum choices, and those choices don't have to return the system to its original state when time is rolled back to the original time.\nExample:\nA photon goes towards an atom, its absorbed by that atom, the atom waits a random amount of time, then it emits a photon in a random direction, and the photon moves away from that atom.\nIf we could start with the end of this sequence and reverse time, then we get the same kind of sequence, but the time the atom exists in an excited state doesn't depend on the original time and so is probably not going to be the same amount of time, and the direction the photon is emitted is also random, so is probably not going to be in the original direction.\nSo we can have both the rules of physics be the same between a frame going forwards in time and backwards in time, and still have the forwards and reversed sequences be different, as long as there are random quantum choices in that sequence.\nSo I think the resolution to Loschmidt's Paradox is this: If entropy increases in a process and so the process is irreversible, it must involve random quantum choices. If a process is deterministic, and doesn't involve random quantum choices, then it must also be reversible and so the entropy in that system will stay the same.", "795" ], [ "Warp drive causality issue, and a possible error in a paper?\nTake a look at this paper on \"Warp Drives and Causality:\" https://journals.aps.org/prd/abstract/10.1103/PhysRevD.53.7365\nThe author attempts to argue that the Alcubierre Drive spacetime could exhibit Closed Timelike Curves, if one is to consider a \"Lorentz Transformation of the coordinates.\" In such coordinates, one finds that a light ray emitted on board the ship could travel backwards in time in such coordinates.\nThe author seems to confuse unphysical coordinate artifact with actual phenomenology. As far as I understand, in GR, one has the freedom to label points on the spacetime manifold by whatever $t, x, y, z$ they like, but the metric tensor remains a physical invariant, regardless of what you call your coordinates. However, its representation in a coordinate system will of course depend on your choice of coordinates.\nTo be mathematically precise, one cannot perform a Lorentz Transformation on the coordinates within the context of a curved spacetime as in GR.", "275" ], [ "If we want to of course, we could transform <PERSON> coordinates, to coordinates which look like a Lorentz Boost, but then we must transform the representation of the metric as well, and in our case we don't have the Minkwoskian structure as we do in SR.\nA light beam propagating inside the vessel will remain within its local light cone, regardless of what you call your coordinates, as specified in <PERSON>'s original paper. The \"Lorentz transformation\" attempted by the author does not hold.\nGenerally speaking, to find a CTC, we are looking for a Timelike trajectory for a particle in the spacetime that returns to the same point on the spacetime manifold. In summary, I do not see that a CTC arises, but that the paper concludes the existence of CTC from a violation of causality in special relativity which is exactly what a CTC does not entail AND an attempt to apply special relativity beyond its domain of applicability. Lorentz Boosts could only be defined Locally at a point in GR, and not the entire spacetime.\nI am only a student, and the author is surely more experienced in GR than me, but I can't see where I am wrong: could someone kindly explain to me where my attempted refutation fails? Sorry for the excessive text...", "275" ], [ "Can we derive most fundamental laws from the Action Principle?\nIt is said in the book Fearful Symmetry - The Search for Beauty in Modern Physics that we can derive all basic laws in physics from a simple principle called Least Action Principle (although it may be better called Stationary Action Principle). I am very excited at the following statements that: (cite page 109):\nThe reader should understand that the entire physical world is described by one single action. As physicists master a new area of physics, such as electromagnetism, they add to the formula for the action of the world an extra piece describing that area of physics. Thus, at any stage in the development of physics, the action is a ragtag sum of disparate terms.\nA picture taken from the book would best illustrate the point:\n* Question:\nAs the author (<PERSON>, from UCSB) is a particle physicist, I have confidence that this is true. But no further detail is given in the book.", "221" ], [ "With Google I could not find any book about Action Principle. Nor could I find any reference to the action shown in the book. Most physics book I read use Action Principle to describe the dynamics of a specific system in that field (e.g action of a free particle or action of the string etc) and then compute the equation of motion. But few of them use the Principle to derive the fundamental law in that area (Except the classic: Mechanics by Landau, in which The Newton's three law was shown to be implied by the Action Principle).\nCan anyone explain that how each of the magic terms in the above Fig.7.4 B may turn into the fundamental laws in Gravity, Electromagnetism, Strong and Weak forces? Or are there books I haven't found yet to describe this exciting law?\nVery sorry for my late response. After spending some days devouring in the books recommended by @hft , I realized that tje difficulty in understanding them. But still I am pleased to find that satisfying answers lie in those books.\nSome more books could be added to the list by @hft For classical mechanics and classical field theory(treating relativistic motion), <PERSON>'s books are always my favourite: Mechanics, third edition, <PERSON> (http://www.amazon.com/Mechanics-Third-Edition-Theoretical-Physics/dp/0750628960 The Classical Theory of Fields, fourth edition, <PERSON><PHONE_NUMBER> The Classical Theory of Fields, fourth edition, Landau (http://www.amazon.com/Classical-Theory-Fields-Fourth-Theoretical/dp/<PHONE_NUMBER>/), where I found good derivation of the Maxwell's equation.", "221" ] ]

[ 1469, 8611, 2640, 1786, 9420, 189, 4108, 938, 10682, 1707, 11146, 2527, 4862, 2882, 1064, 7138, 10604, 4201, 9926, 9487, 3370, 4818, 10469, 2743, 7775, 9380, 118, 10278, 1337, 5968, 2562, 2718, 7872, 4995, 8741, 3562, 932, 886, 2414, 4700, 632, 884, 8332, 1690, 551, 3771, 11162, 3758, 10381, 11427, 1405, 2725, 807, 7168, 9081, 11074, 5643, 10496, 2852, 2476, 10066, 6481, 500, 5708, 401, 11429, 3667, 10996, 5140, 11151 ]

[ [ "A simple proof that under Newtonian gravity rotating massive bodies are ellipsoids?\nHere is my attempt at deriving the shape of an idealized rotating massive body under Newtonian gravity, assuming that the gravity force points towards the center of mass and shape of the body is stabilized. Physically one might imagine an object with very heavy core localized in very small volume at the center, surrounded by very light liquid.\nA point on the surface moves according to $\\ell=\\omega t$, where $t$ is time, $\\ell$ is longitudal angle and $\\omega$ the constant angular velocity. Thus in cartesian coordinates $$ {\\mathbf r}(h,t)=R(h)(\\cos(\\omega t)\\cos(h),\\sin(\\omega t)\\cos(h),\\sin(h)) $$ where $h$ is the latitude (angle) and $R(h)$ is distance to the center of mass (which by assumption does not depend on time, hence also on the longitude since the latter depends linearly on time).\nNet force on a mass $m$ at this point is thus $$ {\\mathbf F}=m{\\mathbf r}_{tt}=-\\omega^2mR(h)\\cos(h)(\\cos(\\omega t),\\sin(\\omega t),0) $$\nIf that mass does not participate in any other motion except the overall rotation, then this net force must be equal to the sum of the gravity force and the normal force at the (frictionless) surface of the planet.\nThe gravity force (with gravitational constant $G$ and planet mass $M$) is $$ {\\mathbf F}_g=-\\frac{GMm}{R(h)^2}(\\cos(\\omega t)\\cos(h),\\sin(\\omega t)\\cos(h),\\sin(h)) $$ and we have to write down the condition that $\\mathbf F-{\\mathbf F}_g$ points normally to the surface.\nOne normal vector is \\begin{multline} {\\mathbf r}_\\ell\\times{\\mathbf r}_h=\\R\\cos(h)((R\\cos(h)+R'\\sin(h))\\cos(\\omega t),(R\\cos(h)+R'\\sin(h))\\sin(\\omega t),R\\sin(h)-R'\\cos(h)) \\end{multline} (I shortened $R(h)$ to $R$ and $\\frac{dR(h)}{dh}$ to $R'$ just to fit the expression on one line.)\nThe condition that $\\mathbf F-{\\mathbf F}_g$ is parallel to it gives $$ \\frac{R\\cos(h)+R'\\sin(h)}{\\frac{GM}{R^2}-\\omega^2R}=\\frac{R\\sin(h)-R'\\cos(h)}{\\frac{GM}{R^2}\\tan(h)}; $$ solving this for $R'$ we arrive at the differential equation $$ R'=\\frac1{\\frac1{R\\tan(h)}-\\frac{2GM}{\\omega^2}\\frac1{R^4\\sin(2h)}}.", "521" ], [ "$$ Solutions of the latter are determined by $$ (R\\cos(h))^2=\\frac{2GM}{\\omega^2}(C-\\frac1R) $$ with arbitrary constant $C$. Switching to $x=R\\cos(h)$, $y=R\\sin(h)$ and denoting $\\frac{2GM}{\\omega^2}=k$, $kC=a$ we obtain $$ y=\\pm\\sqrt{\\left(\\frac k{a-x^2}\\right)^2-x^2}. $$\nAnd now I am stuck since this is most certainly not an ellipsoid.\nWhere is my error? Can all this mess be simplified?", "521" ], [ "Infinite gravitational potential question\nFor this question I use Newtonian gravity only. Relativistic gravitational/kinematic effects are ignored.\nIt is known that the gravity surrounding a point particle of mass $M$ can be described by gravitational potential $\\Phi$ where $$\\Phi=-\\frac{GM}{r}$$ $r$ is simply the distance from the particle. The gravitational acceleration $\\mathbf{a}$ of a test particle (negligible mass) is defined as $$\\mathbf{a}=-\\nabla\\Phi$$ Because Newtonian gravity is linear in potential, the potential of any arbitrary distribution of multiple point masses is the sum of the potential of all the masses.\nI came across a question that I can't seem to answer it myself when trying to analyze two-body problem using the concept of gravitational potential. Assume that there are two point particles $A$ and $B$ with mass $M$ at points $(-a,0,0)$ and $(a,0,0)$ in Cartesian coordinates, initially at rest relative to each other. $\\Phi$ in this case is time dependent because both particles will move towards each other due to mutual gravitational interaction.", "483" ], [ "However let consider initial situation where $\\Phi$ is $$\\Phi=-\\frac{GM}{\\sqrt{(x+a)^2+y^2+z^2}}-\\frac{GM}{\\sqrt{(x-a)^2+y^2+z^2}}$$ and the acceleration at a point is $-\\nabla\\Phi$, as expected. Acceleration becomes ill-defined at points $(-a,0,0)$ and $(a,0,0)$ because it contains the term $0/0$. I think this is not a problem if you interpret this as the acceleration of a test particle, because it is infinitely close to either $A$ or $B$ and therefore experiences infinite acceleration. But, if I need to calculate the acceleration of $A$ itself, obviously the wrong answer is obtained because you can calculate the acceleration using inverse square law and it is finite. One way around this problem is to consider only the potential due to $B$ $$\\Phi=-\\frac{GM}{\\sqrt{(x-a)^2+y^2+z^2}}$$ This gives answer in agreement with inverse-square law. But it raises the conceptual question: Why can we ignore the self-potential of the particle being accelerated? (This is not an issue for massless test particle)\nAlso, how does this work in nonlinear system, such as general relativity where gravitational field also gravitates and produces even more gravity? I don't think you can just ignore the potential because of self-coupling of gravity.", "766" ], [ "Short answer: A rigid hemispherical tear in a vacuum will drop instead of hang when $$ g > \\frac{\\gamma}{\\rho r^2}, $$ where $g$ is the constant of gravity, $\\gamma$ the surface tension of the tear, $\\rho$ the density of the tear, and $r$ the radius of the tear. I estimate that a real tear will drop when $$ g > \\frac{40\\gamma}{\\rho r^2}. $$\nThis is just a back of the envelop calculation. It relies on a simplification of the situation, which may or may not be appropriate, so let me explain.\nWe will model a tear on the eyesocket as follows. We have a container filled with tear fluid. On the side there is a circular hole in the wall of the container, with radius $r$. By some magic the tear fluid slightly bulges out of the hole, forming a perfect hemisphere on the wall, without all our precious tear fluid draining out of the hole.\nOn the one hand we have the surface tension keeping the hemisphere attached to the tear basin. On the other hand, gravity is trying to pull the hemisphere down. We will ignore the deformation of of the hemisphere due to the gravity (it is therefore a rigid tear). It either sticks to the basin or it simply slides down the wall of the container. The question then becomes, how strong must gravity be to make the hemisphere slide?\nSuppose the hemisphere slides. As it slides, the fluid behind hole in the wall will be exposed. This will increase the total surface area of the fluid. The basic physics of surface tension tells us that the increase of this surface area is related to the work done by gravity on the hemisphere, $$ \\Delta E = \\gamma \\Delta A. $$ Here $\\Delta E$ is the difference in energy (the work that is done), $\\gamma$ the surface tension, and $\\Delta A$ the difference in surface area.", "707" ], [ "What we are going to do is transform this difference equation into a differential equation ($dE = \\gamma dA$) in terms of the height of the hemisphere $h$. The hemisphere that is still attached to the basin has $h=0$ and the height decreases as it falls.\nLet's do the energy difference first. The gravitiational energy of the hemisphere is $E(h)=mgh$, with $m$ the mass of the hemisphere and $g$ the constant of gravity. Taking the derivative of $E$ w.r.t. $h$ gives\n$$ \\frac{dE}{dh}=mg\\Rightarrow dE=mg dh $$\nThe area difference is a bit trickier. Let's say we have two overlapping circles of equal radius $r$ (the flat side of the hemisphere over the circular hole). As the circle on top slides over the other circle, a crescent will appear. This is the area that we are looking for. First we find out what this area is and then how it varies as the top circle moves. Let $h$ be the distance between the centers of the circles (equivalently, the height of hemisphere). The area of the crescent is $$ A(h)=\\pi r^2 - (2r^2 cos^{-1}\\frac{h}{2r} - \\frac{h}{2} \\sqrt{4r^2-h^2}), $$ and you can interpret it as: The area of the crescent is the area of circle ($\\pi r^2$) minus the area of the overlap of the cirles (the expression within the parentheses; you can look up the formula for circle overlap). We differentiate the area w.r.t. the height and obtain $$ \\frac{dA}{dh}=-\\frac{h^2}{2\\sqrt{4r^2-h^2}}+\\frac{r}{\\sqrt{1-\\frac{h^2}{4r^2}}}+\\frac{1}{2}\\sqrt{4r^2-h^2}. $$ We evaluate the derivative at $h=0$, because that is where hemisphere starts out, and we find $$ dA=2rdh. $$\nNow we know that $dE = \\gamma dA$, so $$ mg dh = 2r\\gamma dh \\Rightarrow g = \\frac{2r\\gamma}{m}=\\frac{3\\gamma}{\\pi \\rho r^2}\\approx \\frac{\\gamma}{\\rho r^2}, $$ where $\\rho$ is the density of the tear. The second to last equality holds because the mass of the hemisphere equals the density $\\rho$ times the volume $\\frac{2}{3}\\pi r^3$.", "707" ], [ "In general\nYes! A simpler example might be a mass in a 2-D plane attached to four springs (one on each side). Assuming the oscillations are small, the motion of the mass can be described as the combination of oscillations in both $x$ and $y$ directions.\nSolving your example\nIn fact, in your specific example, we do see that phenomenon (for small oscillations!).\nAssume we have a pendulum where the string is actually a spring.", "782" ], [ "For simplicity, I'll restrict the motion of the pendulum to one plane (ie it can swing in one direction, but is blocked along the other).\nThe total energy can be written as the sum of kinetic energy (in both the swing direction and radial direction), and the gravitational potential energy and the spring potential energy.\n$E(l, \\theta)=\\frac{1}{2}m\\dot{l}^2+\\frac{1}{2}ml^2\\dot{\\theta}^2+\\frac{1}{2}k(l-l_0)^2+mg(l_0-l\\cos\\theta)$\nwhere $l$ is the length of the pendulum spring, $l_0$ the \"natural\" length of the pendulum spring if you lay it flat on a table, $\\theta$ is the angle from vertical, dots indicate time derivatives. I set the $E=0$ reference for the gravitational part as when the pendulum is at the bottom of its motion.\nNow let's assume the swinging motion is small: if we Taylor expand the $\\cos\\theta$, keeping only up to second-order in small $\\theta$:\n$E(l, \\theta)=\\frac{1}{2}m\\dot{l}^2+\\frac{1}{2}ml^2\\dot{\\theta}^2+\\frac{1}{2}k(l-l_0)^2+mg(l_0-l)+\\frac{1}{2}mgl\\theta^2$\nBy completing the square, we can combine the third and fourth term, and (ignoring a constant term that appears and just shifts the energy), we find\n$E(l, \\theta)=\\frac{1}{2}m\\dot{l}^2+\\frac{1}{2}ml^2\\dot{\\theta}^2+\\frac{1}{2}k\\left(l-l_0-\\frac{mg}{k}\\right)^2+\\frac{1}{2}mgl\\theta^2$\nLet $x=l-x_0$ where $x_0=l_0+\\frac{mg}{k}$\n$E(x, \\theta)=\\frac{1}{2}m\\dot{x}^2+\\frac{1}{2}kx^2+\\frac{1}{2}m(x+x_0)^2\\dot{\\theta}^2+\\frac{1}{2}mg(x+x_0)\\theta^2$\nThe first two terms look like our usual harmonic oscillator in $x$, oscillating around $x=0$.\nWe note that, if the swing is small ($\\theta$ is small) and the spring movement is small ($x$ is small compared to $x_0$), then $x\\dot{\\theta}^2$ and $x\\theta^2$ have three factors of smallness, and $x^2\\dot{\\theta}^2$ has four! I'll get rid of the $x^2\\dot{\\theta}^2$ term since we already killed off some terms with four factors of smallness when expanding $\\cos\\theta$. Now, rearranging:\n$E(x, \\theta)=\\frac{1}{2}m\\dot{x}^2+\\frac{1}{2}kx^2+\\frac{1}{2}mx_0^2\\dot{\\theta}^2+\\frac{1}{2}mgx_0\\theta^2 + P(x, \\theta)$\nwhere $P(x, \\theta)=mxx_0\\dot{\\theta}^2+\\frac{1}{2}mgx\\theta^2$.\nInterpreting\nForget about $P$ for a moment, and you see we have two independent harmonic oscillator motions happening at once:\n1.", "37" ], [ "All great and valid answers here, and they have helped me see the key piece of the puzzle I was missing: the subtle point that although the instantaneous axis of rotation has zero velocity, it is accelerating upward (centripetal acceleration). Therefore to apply <PERSON>'s second law (or <PERSON>'s law) about this axis, we need to take into consideration the inertial forces/torques that result.\nLet $\\vec{R}$ denote the position of a point on the instantaneous axis of rotation, relative to a fixed point that coincides with the axis of rotation at $t=t'$, but does not accelerate like it. This means that at $t=t'$, $\\vec{R}=0$ and $\\dot{\\vec{R}}=0$ but $\\ddot{\\vec{R}}\\ne 0$. Let $\\vec{r}$ be the position of a particle of $M$ in the rotating system, relative to $\\vec{R}$.", "766" ], [ "Its angular momentum about the fixed point is $$\\vec{L}=M(\\vec R + \\vec r)\\times (\\dot{\\vec R} + \\dot{\\vec r})$$ $$\\vec \\tau=\\frac{d\\vec L}{dt}=M(\\vec R + \\vec r)\\times (\\ddot{\\vec R} + \\ddot{\\vec r}) $$ At $t=t'$, since $\\vec{R}=0$, $$\\frac{d\\vec{L}'}{dt}=M\\vec{r}\\times\\ddot{\\vec r}=\\vec{\\tau}-M\\vec r\\times\\ddot {\\vec R}$$ where $\\vec{L}'$ here is the angular momentum about the instantaneous axis of rotation. The second term on the right hand side is the inertial torque that must be added to the torque due to the real forces: $$\\vec{\\tau}_i=-M\\vec{r}\\times\\ddot{\\vec{R}}.$$ $$\\ddot{\\vec R}=\\omega^2R\\hat{y}$$ where $\\hat y$ is in the upward direction. The intertial torque on mass $m$ in this problem is $\\tau_i=m\\omega^2R^2\\sin\\theta$ (clockwise/inward).\nAll this so far was to derive the expression for the inertial torque. Now writing the second law, with the moment of inertia $I$ taken to be constant, as in case 1 in the question: $$mgR\\sin\\theta + m\\omega^2R^2\\sin\\theta= \\tau'= I\\alpha $$ $$\\alpha = \\frac{g}{2R} \\sin\\theta \\frac{1 + \\frac{\\omega^2}{gR}}{1 + \\cos\\theta} $$ Plugging in $\\omega^2$ leads to the correct expression: $$\\alpha = \\frac{g}{R}\\sin\\theta\\frac{1}{(1 + \\cos\\theta)^2}. $$", "804" ], [ "Goldstein Classical Mechanics exercise 5.17 (3ed) conceptual\nI am having difficulty understanding a concept in the \"Heavy symmetric top\" type of problems. I will include all of my efforts as to hopefully have someone easily point out what it is that I'm missing. The question reads:\nA uniform right circular cone of height $h$, half-angle $\\alpha$ and density $\\rho$ rolls on it's side without slipping on a uniform horizontal plane in such a manner that it returns to it's original position in a time $\\tau$ . Find expressions for the kinetic energy and the components of the angular momentum of the cone.\nI begin by finding the volume (since I memorize no such things) and decide on the obvious choice of cylindrical coordinates.", "15" ], [ "My mass will then be $$\\rho\\int_0^h \\int_0^{2\\pi} \\int_0^{z \\tan{\\left(\\alpha\\right)}}r \\, \\mathrm{d}r \\, \\mathrm{d}\\theta \\, \\mathrm{d}z = \\frac{\\pi \\rho R^2h}{3} $$ then while I'm at it I likewise find the center of mass (in the $z$) $$\\frac{1}{V}\\int_0^h \\int_0^{2\\pi} \\int_0^{z \\tan{\\left(\\alpha\\right)}}zr \\, \\mathrm{d}r \\, \\mathrm{d}\\theta \\, \\mathrm{d}z = \\frac{3h}{4} $$ moving onto the moments for the inertia tensor, I use$$ I_{ij} = \\int_V\\rho \\left(\\delta_{ij} \\Sigma_k x_k - x_i x_j\\right) \\, \\mathrm{d}V $$ and find that $\\bf{I}$ is already diagonal, I get elements $I_1 = I_2 = \\frac{3M}{20}\\left(R^2+4h^2\\right)$; and $I_3 =\\frac{3M}{20}\\left(2R^2\\right)$ so that the inertia tensor about the apex at the origin of the coordinate system is given by $$ \\bf{I} = \\begin{bmatrix} \\frac{3M}{20}\\left(R^2+4h^2\\right) & 0 & 0 \\ 0 & \\frac{3M}{20}\\left(R^2+4h^2\\right) & 0 \\ 0 & 0 & \\frac{3M}{20}\\left(2R^2\\right)\\end{bmatrix} $$\nnow in the event I should need $\\bf{I}{CM}$ I also get that out of the way and find that using the parallel axis theorem, $ I{1_{CM}} = I_{2_{CM}} = \\frac{3M}{20}(R^2+\\frac{h^2}{4}) = \\frac{3M}{80}\\left(4R^2+h^2\\right)$; and $ I_{3_{CM}} =\\frac{3M}{80}\\left(8R^2\\right)$ so that $$ \\bf{I}_{CM} = \\begin{bmatrix} \\frac{3M}{80}\\left(4R^2+h^2\\right) & 0 & 0 \\ 0 & \\frac{3M}{80}\\left(4R^2+h^2\\right) & 0 \\ 0 & 0 & \\frac{3M}{80}\\left(8R^2\\right)\\end{bmatrix} $$\ngreat. So it seems that I may use either the inertial frame OR the body frame, however this is where I'm getting confused. As I understand it, if I change my coordinates to the center of mass body coordinates, I will not need to consider the translational kinetic energy of the center of mass. But can I even do this here? In any event I find $v_{CM} = \\frac{3h}{4} \\cos(\\alpha)\\dot{\\phi}$ where $\\phi$ is the azimuthal angle about the fixed inertial $z$-axis, and I can find various relations for this based on the no-slipping condition though its not clear which I should want. Now that I have gotten most of the legwork done, I want to write my expression for the kinetic energy.", "402" ], [ "Since in retrospect I realise this question can be taken in several different ways, I am posting another reply myself, which combines some of the best answers so far and could hopefully help somebody else understand why this obviously wrong physical reasoning occurs mathematically.\nAs is clear at this point, the original issue was bad notation and there are at least four different ways in which this question can be understood (and resolved). From now on I am going to refer to the current position as $\\vec{x}_0$ and the trajectory as a function of this starting position and time as $\\vec{x}(t)$, such that $\\vec{x}(0)=\\vec{x}_0$, in order to avoid confusion. In all cases the other initial condition $\\vec{\\dot{x}}(0)=\\vec{v}_0$ will not be given much consideration, but we still have to be aware of it.\n1. First scenario: as correctly pointed out, <PERSON>'s second law does not imply that the force comes from a potential and/or is a function of the current position. In this case the force is simply a definition and the question doesn't hold anymore, since the force does not have to be a function of the trajectory:\n$$\\vec{F}(t)=m\\vec{\\ddot{x}}(t)$$\n1. Second scenario: the force comes from a potential, such that $\\vec{F}(\\vec{x}(t))=-\\left.\\frac{\\partial U(\\vec{x}')}{\\partial \\vec{x}'}\\right|_{\\vec{x}'=\\vec{x}(t)}$ and we make a coordinate transformation of the whole trajectory $\\vec{x}(t)=s\\vec{y}(t)$ for some scaling factor $s$. In this case:$$\\vec{F}(\\vec{x}(t))=m\\vec{\\ddot{x}}(t) \\Leftrightarrow \\vec{F}(s\\vec{y}(t))=ms\\vec{\\ddot{y}}(t), \\qquad\\vec{F}(\\vec{x}(t))=\\vec{F}(s\\vec{y}(t))$$ This is a simple change in variables and there is not much else to be found here - certainly no contradictions anyway.\n2. Third scenario: the force comes from a potential and we rescale the initial condition of the differential equation, so that $\\vec{\\tilde{x}}(0)=s\\vec{x}_0$. In general, this trajectory will be completely different to $\\vec{x}(t)$ and the only way $\\vec{\\tilde{x}}(t)=s\\vec{x}(t)$ is if the force corresponds to a quadratic potential.\n3. Fourth scenario: the force comes from a potential and we rescale the solution $x(t)$ of the differential equation, such that $\\vec{\\tilde{x}}(t)=s\\vec{x}(t)$.", "766" ], [ "In general, this rescaled function no longer satisfies the original differential equation and nothing else can be said. The only way the new rescaled trajectory satisfies the original differential equation is if we had a harmonic potential.\nNote that the difference between 3. and 4. is subtle: the new trajectory $\\vec{\\tilde{x}}(t)$ in 3. satisfies <PERSON>'s second law but its shape is in general different to $\\vec{x}(t)$, while the $\\vec{\\tilde{x}}(t)$ in 4. doesn't in general satisfy <PERSON>'s second law (and doesn't have to) and its shape is the same as $\\vec{x}(t)$. In both 3. and 4. the trajectories can only degenerate for a harmonic potential (although one might have to fiddle with the velocity initial condition to achieve that), which is what my original post \"proved\", although it certainly isn't clear whether I proved 3. or 4. (possibly neither) due to my bad notation!", "766" ], [ "We have had a related problem with the brachistochrone problem in Schwarzschild coordinates here. This problem here has struck me as rather odd, for this seems to refer to geodesics, where to me the . However, it has occurred to me there might be a problem here of some relevancy. Suppose we have a string in some orbit around a black hole. We then impose some condition that this string has end points attached to a fixed surface of some kind --- a Dp-brane? This string is then in an orbit around the black hole and will assume some configuration in the curved spacetime.\nSo to set this up we start with the line element, which gives the unit 4-velocity, $$ 1~=~\\Big(1~-~\\frac{R}{r}\\Big) \\Big(\\frac{dt}{ds}\\Big)^2~-~ \\Big(1~-~\\frac{R}{r}\\Big)^{-1} \\Big(\\frac{dr}{ds}\\Big)^2~-~r^2\\Big(\\frac{d\\theta}{ds}\\Big)^2~-~r^2sin^2\\theta\\Big(\\frac{d\\phi}{ds}\\Big)^2, $$ where $R~=~2GM/r$.", "394" ], [ "We identify the $dt/ds$ with the energy $E$ and do some algebra to obtain an equation of motion $$ \\Big(\\frac{dr}{ds}\\Big)^2~=~\\frac{E}{m}~-~1~-~V(r) $$ for the potential function $$ V(r)~\\simeq~\\frac{1}{2}\\Big(\\frac{R}{r}~-~\\frac{L^2}{2mr^2}~+~\\frac{R}{mr^2}\\Big) $$ The $L$ is the angular momentum of the object in orbit.\nWe now use this in the potential for the computation of the shape of the string $$ U_G~=~\\int_0^\\Delta V(r)\\lambda\\sqrt{r'^2~+~r^2}d\\phi $$ $\\Delta~=~D/r$ and $r’~=~dr/d\\phi$ and employ the Lagrange multiplier $U_L$. The Euler-Lagrange equations are applied to the $$ {\\cal L}~=~(V(r)~+~L)\\sqrt{r’^2~+~r^2} $$\nThis is somewhat artificial for it assumes the string endpoints are held apart by some fixed distance. This could be relaxed by treating the endpoints are particle geodesic or orbits. In that case the angular separation of the fixed points varies and the problem is time dependent. This might be an interesting tool to use in some problems with strings and black holes.", "246" ] ]

[ 10274, 786, 10815, 10884, 4376, 7964, 460, 4818, 6157, 719, 3160, 6961, 8931, 149, 10483, 9943, 171, 8623, 3612, 1966, 2087, 1501, 315, 7719, 41, 6029, 1505, 1592, 6178, 6903, 1282, 6306, 6923, 6108, 9167, 4281, 5117, 2753, 10628, 2360, 5687, 5752, 10547, 4125, 4329, 4134, 9574, 1028, 8816, 3617, 6512, 3977, 5434, 4520, 2852, 10002, 4723, 6633, 4712, 3712, 10904, 10517, 785, 9862, 8419, 8553, 1426, 9764, 10241, 9708 ]

[ [ "Why didn't he consider the centripetal force as a force acting on that object.\nBecause Centripetal force is not a force acting on the body. The Centripetal force is not necessarily a unique force in its own right. As an answer pointed out, The \"centripetal force\" is simply defined as the net force acting towards the centre.\nIf there were some more forces acting in the radial direction (for example, if your car was tied with a rope to a tree at the centre of the circle, there would be an additional force of Tension towards the centre) then the sum of the forces would be equal to Tension + the Normal reaction component. This sum would then be considered the centripetal force.\nHere is another way to thing of the scenario : Write the <PERSON>'s law equation for the radial direction without thinking anything about being on a circular trajectory. Don't think anything about centripetal forces for a moment.", "766" ], [ "If were on any other ordinary track, the only force on the car would be $N\\sin(\\phi)$ which then by <PERSON>'s law is equal to $ma$. $$Nsin(\\phi) = ma$$\nNow, because you are moving in a circular path, the \"a\" in the equation must be towards the centre of the circle and its magnitude is a function of the linear velocity at which you are moving in the circular path (specifically it is $\\frac{|v(t)|^2}{r}$ but in your case, v is constant). Now, this is something you have to accept, in circular motion, there must be an acceleration pointing to the centre with the magnitude mentioned above, otherwise the motion would not be circular anymore. Plug this into the equation and you simply get the result as : $$N\\sin(\\phi) = \\frac{mv^2}{r}$$ This pretty much what the other answers said, that the sum of all forces towards the centre (there is only 1 in your case) is the centripetal force. I have taken the opposite sign convention but it doesn't affect the final result.\nTo answer one of your side questions, if $\\phi = 0$, essentially when the road is unbanked and frictionless (as per the diagram), you would never be able to make a turn (In reality, there is always friction to provide the necessary force towards the centre).\nHope this helped.", "544" ], [ "Instantaneous Velocity at a Sharp Point\nMy friend and I are having an argument. Here's the situation:\nA block is at rest on a frictionless surface. At instant $t_0$ a person pushes the block to the right with a constant force. At instant $t_1$ the person stops pushing the block which then glides at a constant velocity $v_f$.\nWhat is the instantaneous velocity of the block at instant $t_1$?\nMy friend says it's a simple \"Newton's Laws\" question and the answer is $v_f$ because there are no forces on the block at that time so it stays in constant motion.\nI would have agreed with him if the question asked for the instantaneous velocity immediately after $t_1$. But I think the right answer is more obscure than that. There are two ways of thinking about this problem:\n1. The Ideal Case\nIn an ideal case, the force is released instantaneously which would result in the following graphs:\nNotably, at $t_1$ the acceleration is discontinuous because the force is released instantaneously.", "512" ], [ "This would mean that the velocity and displacement graphs would have sharp corners at $t_1$. Therefore, in this ideal case, the instantaneous velocity at $t_1$ is undefined because displacement isn't differentiable (the limit from the left is not equal to the limit from the right).\nThis is quite a generous abstraction from reality that would require an infinite force from your muscles to pull your hand back in an infinitely short amount of time. But I don't think it matters, because even in a realistic case, the instantaneous velocity cannot be $v_f$.\n1. The Realistic Case\nIn reality (a non-ideal case) the force by the hand on the block is not released instantaneously at instant 5. This would mean the acceleration dips down over some period of time as shown below. This would mean the velocity graph would be a curve (differentiable) at $t_1$ rather than a sharp point (undifferentiable). I have drawn the realistic curves in red:\nThe conservation of momentum tells us that this velocity curve can never exceed $v_f$ so the realistic case is strictly less than the ideal case around $t_1$. In my mind, this is proof that the instantaneous velocity at $t_1$ must be between the instantaneous velocities just before $t_1$ and just after $t_1$.\nSo who is right?", "766" ], [ "Lets consider the left side wedge to be wedge 1 and the right one to be wedge 2. Considering the block, the wedge 1 exerts a force N1(normal reaction) on the block, the wedge 2 a force N2 and the Earth exerts a force Mg. The wedge 1 experiences normal reaction N1 and a force mg exerted by the Earth. The wedge 2 the force N2 and the force mg.\nFor the block,\nSo, we hence N1=N2=N ( we consider N instead of N1 and N2 as the normal force for the sake of simplicity ).\nNow, for wedge 1,\nSince the same one counts for wedge 2 too, I ain't uploading the image for wedge 2.\nFinally your solution counts as\nSo your solution is obviously correct to the point.\nNext coming to your doubt.The cancelling out of forces etc depends on the way you consider the problem. If you consider the system of the block and wedges as a whole. You see that even though there is \"Internal Movement\" inside the system you considered due to \"Internal forces\" like normal reaction, the system as a whole isn't moving. Hence the total external force acting on the system as a whole would be zero.", "499" ], [ "Hence the External forces F should cancel each other. But if you consider block or wedge by wedge,like we would take for solving problems and equations( like we took here), the forces acting on a particular wedge, lets take it to be wedge 1, has to sum up to be zero since the wedge is in equilibrium. Hence, like we considered it the above problem, the force F is cancelled out by the sine component of the normal force N and vertically, the sum of the cosine component of N and the weight mg is cancelled out by the normal force N'. So, When you come into the system, you can build your distinct relations on how the the external forces cancel out each other. Saying it more simply, suppose this system is just a part of another huge problem and the movements taking place inside the system is of no concern for the the outside the system, then you just consider the external forces F to cancel each other. But if the inside of the system (i.e., the wedges and the block ) is a concern for your problem, then you take it block and wedge by wedge and solve like we did above. Please take it to your attention that as F vary the wedges and block may or may not move.And if this \"may or may not\"movement is of no concern for your question, you just consider the system as a whole. But if this is a matter of concern for your question, then you has to consider the inside too ( block and wedge by wedge ).", "766" ], [ "This is because of greater shear strain you will experience if you run on the train while its accelerating. But us humans do not deform when subjected to this stress but they fall down.\nThere are two factors involved here\n1. Shear force(assuming uniform acceleration)\nWithout using complicated terms, let's assume that you're a passenger(A) watching another passenger(A) standing inside the train. According to you when the train accelerates at $a m/s^2$., the passenger(A) inside accelerates at $a m/s^2$. Let his mass be $m*kg$. Humans generally run at an angle of $15 \\deg$\nNow person (A) has started to accelerate in the opposite direction at $a_1 m/s^2$ at an angle of $15\\deg$*.Due to <PERSON>'s Third Law the force exerted by the train will oppose passenger A\nForce at your feet(when running) $$ \\sum F_{xz}=ma - \\cos(15 \\deg)ma_1$$ $$ \\sum F_{xz}=ma - 0.96ma_1$$\nIn very few cases this force would be in direction of $\\overrightarrow{ma}$.", "771" ], [ "Believe it or not except high speed bullets, normal trains accelerate very slowly.\nAlso due to Newton's Third Law, the forward acceleration of your head will be equal to the backward acceleration\nShear stress tends to deform originally rectangular objects into parallelograms. The most general definition is that shear acts to change the angles in an object.\n$$\\tau_{xz} = \\frac{F}{A_{xz}}$$\nAnd if you also want to know shear strain $$ \\tan \\gamma_{zx} = \\frac{\\Delta x}{z}$$ $$\\gamma_{zx} = \\tan^{-1} \\Bigr ( \\frac{\\Delta x}{z} \\Bigr)$$\n* z is height of the person\n* $\\Delta x$ = ? $$\\sin(15 \\deg) = \\frac{\\Delta x - s_{net}}{z}$$ $$\\sin(15 \\deg)z = \\Delta x - s_{net}$$ $$0.25z + s_{net} =\\Delta x$$\n* Let $a-0.96a_1$ be $a_{net}$\n$$s_{net} = ut + \\frac{1}{2}a_{net}t^2$$\nSince humans are not rectangular, this is just an approximation, also air resistance and friction do not come in this approximation.\nNow if passenger (A) were just to stand, he would not exert any force on the train, nor would the train exert any force on him due to <PERSON>'s third law. Thus\n$$\\tau_{xz} = \\frac{0}{A_{xz}}$$ $$=0N/m^2$$ Since there is no force there is no displacement and person is perpendicular to the ground while standing,shear strain equals zero too. $$\\sin(90 \\deg) = \\frac{\\Delta x -0}{z}$$ $$\\frac{\\Delta x -0}{z} = 0$$\n$$\\gamma_{xz} = \\arctan (0)=0$$\n1. Friction\nAll of us know that without friction we won't be able to stand. While running friction is lesser as compared to state of rest of an object in contact with the ground. Therefore a moving object will experience less friction, and will be more likely to fall.\nConclusion : You are more likely to fall if you run in the opposite direction of the train's acceleration than standing still on the train", "766" ], [ "Newtonian Mechanics - How does something like a car wheel roll?\nOk so please bare with me here and what is almost certainly a really stupid question, partly because I don't quite know how to ask it.\nWhen you have a wheel such as one attached to a car, a torque is applied to it from the engine. It's my understanding that the wheel would slide over the road and the car would not move if it were not for static friction which is of course the concept of rolling without slipping.\nThe problems I am having is when I consider what the magnitude of the force exerted on the road from the wheel would be, or specifically the equal and opposite force exerted back onto the wheel from the road via static friction. The reason for this is because I want to say that it is just the torque exerted on the wheel by the engine divided by the radius of the wheel but that seems to lead to a ridiculous conclusion.", "544" ], [ "If I follow that logic, then the equal and opposite force exerted on the wheel by the road, multiplied by the radius of the wheel to get the counter-torque, is equal to the torque exerted on the wheel by the engine but in the opposite direction. That of course would mean that there is no net torque and the wheels would never move (unless the force were greater than that available from static friction but then it would just slip) which means that the car would never be able to move! So simply put, what am I missing that is almost certainly staring me in the face (again)? Clearly things roll and cars move so I know i'm going horribly and embarrassingly wrong somewhere.\nAlso, I often hear people say that static friction is the force responsible for propelling a car forward. How is that the case when it acts in the direction opposite to the direction that the wheels are trying to roll? That's sort of the same question but I think it may help highlight my misunderstandings of rotational motion in this area.\nI never knew wheels could be so complicated! At least for me anyway.", "544" ], [ "Before starting, the meaning of tendency needs to be clarified. I believe that by Tendency, your teacher means the obstructed motion of a body (or a fluid) under a force.\nA liquid has the tendency to move down due to gravitational force (or under influence of gravitational force, same meaning). But the liquid’s downward motion has been obstructed by the container in which it is kept.\nHow can tendency of shifting away alone, change the pressure at point A ? Shouldn't the liquid at A move away from it in order to decrease the pressure there ?\nThis question can be answered both qualitatively and quantitatively. You have already derived the result quantitatively using <PERSON>’s laws of motion and a few assumptions. What remains is to understand the result qualitatively.\nThere are many-many ways to understand this.", "927" ], [ "One way is the way presented by your teacher. Another way presented in other answers is as follows:\n* When at rest, the weight of the liquid in vertical column and the force exerted by atmosphere causes the liquid to apply force on the rightmost wall.\n* When the tube is accelerated horizontally towards the right, a pseudo-force or fictitious force acts towards the left on the liquid in horizontal column with respect to the tube.\n* This reduces the force exerted by the liquid on the rightmost wall, thus reducing the pressure at point $A$.\nBelow, I would like to present another way to derive the result. I have found this method to be much helpful while pondering over your question.\nAssumptions\n* The liquid is incompressible.\n* The surface tension is ignored (I am not even sure what will happen to the meniscus under horizontal acceleration).\n* The tube is thin (so that the horizontal pressure variation in vertical part and vertical pressure variation in horizontal part could be ignored).\nDerivation\nWe use only <PERSON>’s laws of motion to derive the result. We take the ground as the frame of reference.\nWe choose a thin cylindrical part of the liquid with one end adjacent to the rightmost wall of the tube and another end directly at the end of vertical part of tube, and analyse the forces acting on it.\n$F:$ The buoyant Force.\n$\\delta N:$ Normal Force applied by wall.\n$\\rho :$ Density of liquid.\n$P_0 = P_{atm} + \\rho gH$ : Force applied by liquid on left of the part of liquid.\nWe take a small circular cross-section ($\\delta A$) to ensure negligible change in pressure across height of cylinder.\nLet $P_i$ be the pressure exerted by liquid on the wall when tube is at rest. And, let $P_f$ be the pressure exerted by the liquid on the wall when the tube is accelerating.\nUsing <PERSON>’s third law: $$ P_i \\delta A = \\delta N_i \\tag{1}$$ $$ P_f \\delta A = \\delta N_f \\tag{2}$$ $N_i$ and $N_f$ are the Normal Forces in the two states.\nWhen the part of liquid is in equilibrium: $$P_0 \\delta A = \\delta N_i$$ $$P_i = P_0 \\tag{using 1}$$\nNow, when the tube is accelerating horizontally towards the right with acceleration $a$: $$ ma = P_0 \\delta A - \\delta N_f$$ $$ \\rho la = P_0 - \\frac{\\delta N_f}{\\delta A} \\tag{3}$$ Then: $$ \\rho la = P_0 - P_f \\tag{using 2 and 3} $$ $$ P_f = P_0 - \\rho l a $$\n$$ P_f < P_i $$\nNote: If the presented set of assumptions is not sufficient then please comment.", "439" ], [ "In the proof where we find out minimum velocity such that it completes a rotation, we say that at the topmost point the centripetal force cancels the gravity force and hence tension is zero. Using this we find the horizontal velocity and plug it into the energy conservation equation.\nFor this case, if the velocity at the topmost point $H$ is $0$ then the bob just falls down. Even if we give the bob some small horizontal velocity at the topmost point it follows a parabolic path and falls down (because the string is not taut). Still, if the velocity at the topmost point is $0$ then velocity at the lowermost point $L$ will be $\\sqrt{4gr}$ (by energy conservation principle). That means if we were to give the <PERSON> a horizontal velocity of $\\sqrt{4gr}$ at $L$ it would complete its circular motion up to the point some point $P$ between $A$ and $B$, at which tension in the string would be zero, and then fall following a parabolic trajectory.", "246" ], [ "That means there is some minimum horizontal velocity $v_0$ for which the tension of the string will not be zero, bob will not start falling and will continue with its circular motion around the circle. That velocity comes out to be $\\sqrt{5gr}$.\nHowever, when it is made to complete one quadrant there is no requirement to calculate a limiting velocity because there is nowhere to follow a parabolic path (there is nowhere to fall even if the tension in the string becomes zero). We can just use the energy conservation equation to calculate the velocity at whatever point we may require. If you don't want to directly apply the equations of energy conservation you could proceed by finding out the equations of motion $$\\ddot{\\theta}=-\\frac{g}{r}\\sin \\theta$$ This innocent looking differential equation is actually quite nasty and does not have a solution using elementary functions. You could, however, proceed by using $$\\ddot{\\theta}=\\dot{\\theta} \\frac{d\\dot\\theta}{d\\theta}$$ whose first integral will just give you back the energy conservation equation (or it might take you nowhere!).", "499" ], [ "Two initial observations :\n1. Are the darts launched with the same speed or the same kinetic energy?\nWhen you specify that you use the same 'force' to launch both darts, it is not clear what you intend. Using the same force in Newtons over the same distance should result in the two darts acquiring the same kinetic energy but different speeds. However, as <PERSON> points out, your ability to launch objects is limited by the mass of your arm. If the mass of the arm is much larger than the mass of the dart, very little KE is imparted to the dart. All light-weight objects are launched with approximately the same speed, which is limited by size and strength of the arm and the technique used. See Physics of Overarm Throwing.\n1. The effect of gravity is a complicating factor here, so let us ignore it.\nIf there was gravity but no air resistance, the object launched with the greater speed would travel further.", "621" ], [ "The range of a projectile without drag is proportional to $v^2$ and is independent of mass. If there is both gravity and air resistance the situation becomes more complex, except when the objects are launched close to straight up or close to horizontal. Darts are usually launched close to horizontal.\nWith Air Resistance (Drag) but no Gravity\nFor the same shape and size of object, travelling at the same speed, the drag force $F$ caused by air resistance is the same. It depends on cross-sectional area but not mass. For thrown objects, drag force is approximately proportional to speed through the air : $F=-kv$.\nThe equation of motion is $a=F/m$ so that $\\frac{dv}{dt}=-(k/m)v$ which has the solution\n$v(t)=v_0e^{-bt}$\nwhere $b=k/m$. Integrating again we get\n$x(t)=(v_0/b)(1-e^{-bt})$.\nThe distance travelled after a long long time is\n$x(\\infty)=v_0/b=mv_0/k$.\nWhich dart travels further depends on the initial momentum $mv_0$.\n1. Launch with the same KE\nHere $\\frac12mV^2=\\frac12Mv^2$ (the lighter dart has higher velocity) so $V/v=\\sqrt{M/m}$. The ratio of distances is\n$x_M/x_m=Mv/mV=V/v=\\sqrt{M/m}$.\nThe heavier dart travels further, despite the fact that the lighter dart started with higher speed.\n1. Launch with the same Speed\nThe above result indicates that the heavier dart will travel further still, because the lighter dart starts with less KE.\nHere $V=v$ so the ratio of distances is\n$x_M/x_m=Mv/mV=M/m$.\nThe heavier dart travels further still than when the darts have the same KE.\nConclusion : In both scenarios the heavier dart travels further.", "512" ] ]

[ 1109, 1912, 7238, 7872, 3314, 4163, 6029, 3742, 7775, 7397, 5968, 11224, 9786, 5752, 1707, 10015, 1074, 8614, 11142, 6549, 11336, 4520, 5828, 10342, 9370, 171, 1140, 608, 4062, 6237, 10476, 7959, 6801, 10904, 1829, 6523, 5025, 9662, 874, 4281, 7815, 3581, 9943, 403, 6178, 1966, 10410, 9580, 11090, 5173, 10245, 6191, 1086, 3135, 3818, 469, 5312, 19, 8623, 7719, 7073, 2433, 2302, 3995, 5354, 1278, 8419, 5686, 5117, 785 ]

[ [ "Following-eye Halloween Display\nIntroduction: Following-eye Halloween Display\nThe glowing eyes follow you as you walk down the street. A spooky effect that is cheap and easy to make! Put one in every window for a really creepy effect! Made from cereal boxes, cardboard, and paper mache.\nSome of the rave reviews I got from popular celebrities:\n“Your house is creepy!” - Spiderman\n“Great job, as usual your house looks fantastic!” – Pirate <PERSON> mom\n“I told my neighbor her house was the best, now I’ll have to take it back!” – <PERSON>’s Mom\n“This house is awesome, I want to adopt you!” – Grim Reaper\nStep 1: The Inspiration\nThe idea for this Halloween display came from this decorative mask. The eyes follow you as you walk around the room. I studied this to learn how the effect works and how to enlarge it to a window-sized display. The front of each eye is a spherical shape with an eye shaped cutout. The pupil is on the back of a cavity behind the eye. The pupils are dome shaped so that they appear circular from all angles. The center of the pupil's dome shape is located about at the center of the spherical shape of the front part of the eye. This makes the pupil appear to be oriented directly at you from all angles.\nThe paper mache eyes in this instructable are giant-sized replicas of the eyes in this mask. The cereal box eyes are a common craft project I think, I have heard of them being made from shoe boxes.\nStep 2: Materials\nYou need:\nLarge pieces of cardboard, big enough to fit in the windows. Heavy cardboard is better.\nBlack paint. I used tempura paint, the kind used in kids art classes, from an art store ($7 for 900 ml, I used about half the bottle for 4 window displays), it is cheap, easy to clean up, and dries to a flat black finish. That's the only thing I had to buy to make my display.\nChristmas lights (LED lights strongly recommended because they don't get hot - the materials are very flammable!).", "644" ], [ "White is best, but other colors will work too. Multi-colored strings are probably not going to work well.\nWhite paper.\nWhite glue.\nA black marker.\nScissors.\nA sharp knife.\nA drill.\nFor the smaller eyes:\nSeveral cereal boxes. 3 or 4 for each window you want to do.\nColored paper. I used construction paper.\nTape. Packing tape works well.\nFor the larger eyes:\nNewspapers (one large newspaper should do).\nFlour and salt for the paper mache paste.\n1 large (13\") and 1 medium (9\") mixing bowl.\n1 softball\n1 large plastic ice cream container\nPlastic food wrap. Glad Cling Wrap worked well, it is a heavier grade plastic and actually not very sticky which is good because the purpose is to help release the paper mache from the molds.\nAllow about 2 weeks to make everything, there are several steps where you need to let things dry overnight.\nStep 3: Cereal Box Eyes - Cut the Eyes\nThe eyes made from cereal boxes are easy to make, so you can make several for each window. The large paper mache eyes take longer to make but give a better effect when viewed from the street. I will start with how to make the cereal box eyes.\nDraw eye shapes on the front of the cereal box. Cut out the shape with a sharp knife.\nIf the box is more than 1-1/2\" thick, cut the box in half, making sure the sides of the back half are about 1-1/4\" to 1-1/2\" wide. In the picture, the sides of this box are cut a bit too narrow.\nStep 4: Cereal Box Eyes - Glue on Paper\nTake a sheet of white paper (it can be scrap paper already printed, as in the picture). Cut it to fit inside the front of the cereal box. It doesn't matter if it fits exactly.\nPlace the paper under the front of the cereal box and trace the eye shape onto the paper. If already printed one side, place the printed side up as shown.\nCut out the eye shapes, about 1/4\" outside the lines.\nGlue the paper to the inside of the box front.\nThe purpose of this paper is to increase the reflectivity of the inside of the box, so the eyes glow brighter.\nStep 5: Cereal Box Eyes - Draw Pupils\nCut a piece of white or colored paper to fit inside the back side of the box. I used pale colors, but after seeing the completed display I think some darker colors would work well too.", "286" ], [ "Giant Cicada Sculpture Using a Paper Lunch Bag\nIntroduction: Giant Cicada Sculpture Using a Paper Lunch Bag\nEvery 17 years the Brood X Cicadas emerge from underground to live with humans who reside around the middle of the eastern half of the United States. They are loud and harmless and should be celebrated. And what better way to celebrate them, than by making a giant cicada sculpture using a recycled paper lunch bag and a few other art supplies?! My mom was an art teacher for 30 years and made these with her students 17 years ago, so I asked her for a special online lesson for myself and my daughter and we agreed it should be documented in an instructable. We simplified the cicada parts a lot for this project, my daughter is 6, but it would make a great activity to look closer at cicadas to get some of their features more precise. In the end, my daughter loved them and they are her new bug friends.\nSupplies\n1. Paper bag (I used lunch box size and a little larger too)\n2. Red clay that hardens (I used play dough because that is what I had, but Model Magic or Sculpey would work well)\n3. Construction paper (black or brown for the legs and antenna, yellow or white for the wings)\n4. Hot glue (although regular liquid craft glue or school glue would work if you're patient)\n5. 1 rubber band\n6. Masking Tape\n7. A few sheets of newspaper\n8. Scissors\n9. Crayons\n10. Black permanent marker\n11. Pencil\n12. Black pipe cleaners (optional)\nStep 1: Sculpt the Eyes\n1. Sculpt the eyes first so they can dry while you make the rest of the bug. Use red clay to make a sphere about 1-1.5\" inch in diameter, like a large marble size.\n2. Cut the ball in half (we used the scissors)\n3. Reshape a bit to make sure the bottom is nice and flat and the top nice and round\n4. Make a small dot with the permanent marker on the top of each sphere\n5.", "286" ], [ "Set aside and let dry (or bake if you used Sculpey)\nStep 2: Color the Bag\n1. Add a small wide \"V\" to the bottom of the bottom flap of the bag with a black crayon\n2. Lightly color the bottom flap on the front and back with a black crayon\n3. Draw 3 curved lines to the front and back of the bag, about 1\" apart from each other\nStep 3: Stuff Your Bug\n1. Take your newspaper (or any other scrap paper) and make around 5 balls, the number will depend on the size of your newspaper and yout starting paper bag. Stuff the crumpled balls into your bag, putting about 2 in the bottom for the head, and the other 3 in the middle for the body.\n2. Scrunch the opening of the bag and tape around it to enclose the paper balls and end of the abdomen of your cicada\n3. Scrunch around the head and put the rubber band around this area. The rubber band shouldn't be too tight since cicadas don't actually have necks, but it gives it a nice shape.\nStep 4: Make the Wings\nYou need a full sheet of paper for the wings, I used white copy paper and added a goldish color to them at the end, but you could use a yellow paper or even find something slightly translucent.\n1. Fold the paper in half lengthwise.\n2. Starting in the middle of the short side draw a curved lines that goes to the middle of the long side and back to the middle of the opposite short side.\n3. Draw a straight diagonal line up about about 1/3 the way across the opposite long side.\n4. Draw a straight line connecting to the original point on the short edge.\n5. Hold your wing vertically so the wider side is on the bottom.\n6. Draw 3 slightly curved lines coming from the top middle.\n7. Draw 3 upside down \"U\" shapes from the end of each line to the bottom of the wing.\n8. Outline the wing and trace these lines with the black crayon.\n9. Flip the paper over and trace these same lines on the back. We held our paper up to the window to be able to trace easily.\n10. Keep the paper folded and cut out the wings.\n11. Color front and back of each wing if wanted.\nStep 5: Cut Out the Legs and Antenna\nWe simplified the legs a lot and made them L shapes, about 2 inches in height with a 1\" foot. They are about 1/4\" thick.\n1.", "636" ], [ "Enlarging an Image Using a Grid\nIntroduction: Enlarging an Image Using a Grid\nAny home brewers out there?\nI am the king on mediocre home brewing and I'm going to show you how I enlarged one of my beer labels using a simple grid method.\nSupplies\nMaterials\n-Print out the image to enlarge\n-Scissors\n-Boxcutter\n-Ruler\n-Pencil\n-Red marker\n-Black marker\n-Paint\n-Paint brushes\n-Top coat\nTools\n-Jigsaw\n-Orbital sander\nMolding\n-Silicone molds\n-Polymer clay\n-Wood glue\nGold leaf\n-Gold leaf\n-Gilding glue\nStep 1: Draw the Grids\nYou totally remember the \"grid method\" from elementary school, but it basically involves drawing a grid over a reference picture, and then drawing a grid of equal or larger ratio on something else. Once the grids are finished, you draw the image on the new canvas focusing only on one square at a time.\nI doubled my image. I drew a 3x3cm grid on the printout of the beer label and made a 6x6cm grid on a piece of plywood.\n*You'll need to draw the exact same number of lines on the canvas as you did on your reference picture, and that in both cases, the lines must be equally spaced apart.\nIt's super easy and the best part is this is a low-tech, kid friendly way to draw any picture you like.\n*To help yourself focus on a square, use a boxcutter to cut out a matching square in a sheet of paper.\nStep 2: Cutting\nI used a jigsaw to cut out the oval and then I sanded it down.\nStep 3: Clay Moldings\nCreating polymer clay molding is easy!\n-Press polymer clay into the molding, filling every nook and cranny and keeping the top as level as possible\n-Paint a layer of PVA glue, epoxy resin, or gorilla glue onto the surface of where the mold is going.\n-Gently pull the clay out of the silicone mold. Don't wait for the clay to dry.\n-Paint the same glue on the back of the clay you just pulled out, and then gently press it onto the surface.\n-Let it dry for 24 hours.\n*You don't need to paint the surface first. I did, because I was trying to figure out my colors.\nStep 4: Drawing, Painting and More Molds\nI drew the image onto the wood going square by square.\nI started with the oval, painted it and continued on with the banner and \"Pilsner\" font. It was a little time consuming and I made a couple adjustments to the \"Pilsner,\" because it was too straight on the printout.\nStep 5: More Font\nI thought I could pressure engrave the font to where it would show up under a coat of paint.", "74" ], [ "NOPE! I wish I used a dremel tool. A few letters showed through, but I needed to draw arches and measure spaces since the grid was painted over. I also wish I didn't use chalk paint! Dang it! I mean, I really like how it looks, but it would probably look nicer without that chalk paint texture.\nStep 6: Gold Leaf\nFor gold leaf.\n-Brush on gilding glue and wait for it to become tacky. About 20 minutes.\n-Apply the gold leaf by placing it over the glue.\n-Remove the unused leaf by smoothing the wrinkles with your finger or a small paint brush.\n*The glue must be tacky or else the gold leaf is tough to apply. It'll slip around and get stuck to your fingers and brush.\n*Gold leaf gets everywhere too! Really....everywhere! It breaks down into little gold specks while you smooth, so keep cleanup supplies nearby and turn off the ceiling fan.\nStep 7: Finished!\nTop coat and hang!\nI'm starting to like the chalk paint texture now too. This was a really fun project and took me back to elementary school.", "959" ], [ "Easy Clay Pumpkin Sculpture\nIntroduction: Easy Clay Pumpkin Sculpture\nHere is a technique for making a sculpture of a pumpkin that easily captures a pumpkin's form. I used an air dry clay similar to model magic, but this technique could work for other clays as well.\nSupplies\n1. Model Magic (Orange and Green, but you can color white clay with washable markers)\n2. Green Pipe Cleaners (optional addition)\n3. Tooth Pick (optional tool)\nStep 1: Color Clay With Marker\nI started with orange clay but needed to make the green clay for the stem and leaf.\n1. Flatten the clay and color all over it with marker\n2. Fold it in half enclosing the colored part\n3. Knead the clay to mix the color in\n4. Repeat this until you get the color you want\nStep 2: Divide Orange Clay\n1. Start with a ball of clay a little smaller than the size you would like your finished pumpkin\n2. Divide orange clay into 6 even pieces\n3.", "994" ], [ "Form each piece into a round ball\nStep 3: Form Pumpkin Pieces\n1. Take each ball and roll it into a cylinder shape. Mine here looked like fat baby carrots, but you can do different thicknesses and lengths to get different shaped pumpkins\n2. Align all the pieces in a straight line along their long edges\nStep 4: Add the Stem\n1. With the green clay, create a stem and leaf\n2. The stem can be made by rolling a cylinder that is a little longer than the height of the orange cylinders\n3. The leaf should have a stem about 1\" long to tuck into the middle of the pumpkin. (optional: toothpick can be used for details)\n4. If you want a pipe cleaner vine, cut it to size and spiral it\n5. Add all the pieces to the middle of the laid out pumpkin pieces as shown\nStep 5: Roll the Pumpkin Together\n1. Connect the first orange cylinder with the last orange cylinder by rolling the pieces together, keeping the stem in the middle.\n2. Your pumpkin is done, but you can squeeze it a little to give it a shape you like and use the tooth pick for some additional details.", "286" ], [ "DIY Halloween Cornstalks\nIntroduction: DIY Halloween Cornstalks\nCreate homemade cornstalks for interior or protected exterior projects from simple items.\nSupplies\nYou’ll need: PVC Pipes, Brown Packing Paper roll, masking tape, tan spray paint, and scissors.\nStep 1: Start Creating the Leaves.\nGet a roll of brown packing paper at your local home improvement store. (Usually about $3 a roll) I tore off quite a few sheets about the same size...maybe about 1-1.5 feet long, just depends how big you want the leaves to be. After you tear off the sheets, stack them and fold them in half, longwise. I then cut out a leaf shape through all the sheets. By folding it in half, you can get double the amount cut in less time.\nStep 2: Spray the Pipes.\nCut your PVC poles to the height that you prefer. I made a bunch of random height stalks because I was going to use them for a couple different types of displays.", "6" ], [ "Then spray the base pole with the spray paint so the white doesn’t show.\nStep 3: Crinkle the Leaves and Attach.\nSo after the leaves are cut out, you’re going to grab a stack, maybe 6-10 sheets, and literally crinkle them up with a twist in your hands. You want them to wrinkle. After you crinkle them all, pull them apart so you have a box or stack of crinkled sheets, read to attach.\nNext, grab one of the sprayed base poles from previous step and wrap one leaf around the top of the pole and secure it with masking tape. Use the wider end for the pole and the pointy end hanging off the pole, then shape by hand so it points out and away from the pole.\nNext wrap the next leaf around the base of the previous leaf, covering the tape so it’s hidden. Then continue this pattern all the way down the pole, adding as many leaves as you desire.\nAt the base, I used some extra paper and crinkled it just to wrap around the very bottom of the stalk and taped it in place.\nStep 4: That’s It!\nYou’re basically done at this point. I’ve attached some images of the projects I used this for.", "984" ], [ "Howl's Moving Castle Earrings- Studio Ghibli\nIntroduction: Howl's Moving Castle Earrings- Studio Ghibli\nHowl's Moving Castle is one of my favorite Studio Ghibli movies. I find it inspiring.\nOne of the most sought-after pieces of Studio Ghibli jewelry is Howl's jewelry set. They sparkle like magic and are pretty pieces in themselves without having belonged to a handsome wizard. Today I am going to show you how to make your own Howl's Moving Castle earrings. I will be publishing Instructables on the necklace and ring as well.\nSupplies\nEarrings:\n1. Clay in green\n2. Eyepins\n3. Gold hook earrings\n4. Two small glass red seed beads\n5. Wire in 24 gauge\n6. Pliers\n7. Green pastel\n8. Knife or toothpick to scrape and mix pastel\n9. Soft brush\n10. Triple Thick (or TLS for polymer clay)\nStep 1: Sculpt Teardrop Shapes\nWith the green clay, roll it between your fingers, making one end smaller than the other, to make a teardrop shape. Insert an eye pin at the top of the tear drop. Make two. They should be about as long as a quarter is from side to side.", "95" ], [ "Bake or leave to dry.\nStep 2: Adding Red Gems\nGet out the gold earring hooks, piece of wire, and the glass red seed bead. With the round nosed pliers, curl one end of the wire piece into a loop. Slide the red bead onto the wire. The loop will stop it from coming off at the end.\nTake the round nosed pliers and curl a second loop on top. You will probably have to remove your pliers and pinch it closed. Now the bead should be trapped by the two loops.\nOpen the loop on the earring hook by twisting the loop sideways where it meets. Don't pull it open. Slide on of the loops on the piece of wire onto the loop on the hook, then twist the hook closed, trapping the bead's wire loop on the hook. Do the same for both pieces.\n*If you had gold wire it would be more accurate, but I didn't have any, so I had to go with silver.\nStep 3: Attach Earrings\nGet out the dried/baked tear drop shapes. Open the loop on the eye pin on the tear drop shape. Hook it to the end loop on the bead wire, making it hang from the bottom. Close the eye pin loop.\nStep 4: Triple Thick Varnishing\nTo give them a bit of a luminescent appearance, I will be varnishing them with Triple Thick mixed with green pastel. I chose a darker shade of green pastel so that they could look like they \"glowed\" from within.\nScrap off the pastel stick into a powder. Mix this powder with a bit of Triple Thick varnish. Continue mixing until you get an even color.\nWith a brush, apply the colored Triple Thick to the teardrop shapes. Be careful not to overwork it; you can go back and add another coat later, but if you keep brushing what you have applied it will become lumpy.\nI applied three coats in total.\nStep 5: The Earrings of <PERSON>\nAnd there you have it! You have these magical earrings. You can sport your Studio Ghibli style without screaming, \"I love Studio Ghibli!\" (even if you might want to). These earrings can be worn to formal events without standing out as fan jewelry and still being pretty.\nI have another Studio Ghibli tutorial already published here. I am working on more Instructables about <PERSON>'s jewelry.\nGo clay today!", "902" ], [ "Rainbow: Salt Crystal Painting\nIntroduction: Rainbow: Salt Crystal Painting\nHello everyone,\nThis instructable is about salt crystal painting. It is a fun and interesting STEM activity that you can do with your child.\nFor this instructable I used a rainbow theme to make this painting as it was easy to draw.\nThe Science Behind The Salt Painting Science Experiment:\nThe salt absorbs or soaks up the water through a chemical action. Salt is hygroscopic which means that it can absorb both liquid water and water vapor in the air. This Salt Painting Science Experiment is a fun way to combine art and science together.\nSupplies\nWatercolors (Liquid watercolors are great for this activity. If you don’t have any, you can make your own by watering down food coloring.)\nPaper ( thick paper or cardstock)(Any sturdy art surface will do. I've done this with card stock, poster board, cardboard, watercolor paper, paper plates, and foam core.)\nWater\nTable salt\nPaint brush or eye dropper or pipette (whatever is easily available)\nPencil\nCompass\nGlue\nStep 1: Drawing\nTo paint, we have to draw first. I made the drawing of a rainbow, which is very easy to draw, put your pencil in compass and draw concentric semi- circles.\nStep 2: Sprinkle Salt\nSqueeze glue onto the lines you drew of the rainbow. Start by the topmost one Violet ( I wrote the names of the colors but you don't have to do this) and then one by one climb down to Red.\nCarefully sprinkle salt onto cardstock until the glue is thoroughly covered.", "994" ], [ "Do this before the glue has dried so that the salt sticks to it well. Tip to let excess salt fall away. A baking dish or tray will help to contain the salt.\nStep 3: Add Color\nYou can either wait for the glue to dry, or move directly on to coloring your creation.\nDip your paint brush into liquid watercolor paint then gently touch to the salt-covered glue lines. Watch the paint “magically” travel in both directions!\nTry to drop the water only onto the salt crystals themselves, and not onto the actual cardstock. You can mix colors to see what new shades they make.\nIf you like, you can use a dropper or pipette instead of a paint brush to add your watercolor paint. You'd find that this can add a bit too much paint at a time, but I know that many people like this method. Set the salt crystal drawing to the side for several hours to dry completely before displaying. The drying process may even take a day or two.\nExperiment with different designs and colors to see how your salt crystal paintings change. You can even try different different backdrops like cardboard and tin foil to see how those effect your paintings.\nYou can use this glue + salt + watercolor technique to write names/words, nature scenes, squiggles and scribbles, faces, and more!", "1013" ], [ "Papier Mache Shark Head Prop for Costume\nIntroduction: Papier Mache Shark Head Prop for Costume\nI made a shark head with the open jaw out of papier mâché for a Halloween costume a few years back. The shark needed to look life sized and somewhat menacing, as though it was about to jump out of the water and get you.\nIt took about about a week total (to allow for drying time between layers and painting).\nHere are the steps I took to make it!\nStep 1: Supplies\nFor this project, you need:\n-An old corrugated cardboard box to create the shape of the cylindrical body\n-A Latex Balloon (10\" or so - depending on the shark head size you want!)\n-Packing tape\n-Newspaper\n-Glue (several type work - White, Wood, Tacky Glue)\n-Flour (for papier mâché paste)\n-Water (for papier mâché paste)\n-Heavy grade brown paper bags, for papier mâché, ripped up in small pieces and removing all sections of the bag that have glue remnants or are raw edged (you want the teared edges to create a good seal of each piece)\n-White Styrofoam scraps to create the teeth\n-Rasp or sanding block to shape the styrofoam teeth\n-1\" styrofoam ball, cut in half to create the eyes\n-Acrylic paints - White, Black, Red (and gray, pink, if you don't want to mix your own)\n-Paintbrushes - larger and smaller for detail work (around the teeth)\n-Pink fabric to line the inside of the mouth & Hot glue to attach fabric (optional)\n-Clear gloss finish to make shark (and it's teeth) look slick and wet - I use either Elmer's Clear glue or a Decoupage Gloss\nStep 2: Shaping of the Shark Head\n1. Take your cardboard box and break it down. Next, you want to roll it out along the length of the corrugated cardboard (with the \"lines\" of the cardboard), to get the cardboard to coil naturally into a cylinder shape.\n2. Inflate your balloon to the desired size and knot the end.\n3. For your shark body, create a cylinder that is the same diameter as the thickest part of your latex balloon. Staple or tape the cylinder cardboard into place so it won't come undone. Let the balloon hang out at the top of that cylinder opening, \"nose\" or knot up. It should hold in there without tape, but let's go ahead and secure it with a little packing tape. It doesn't have to look pretty - it will all be covered with papier mâché.\n4. Get your newspaper and shape some crumpled pieces to flesh out the rest of your shark nose.", "286" ], [ "Use pictures in books or on the internet for inspiration! You can affix the newspaper where you want it with packing or duck tape. For the very tip, which is a little flat and pointy, I used a long strip of folded newspaper and folded that strip over the whole point - then taped that into place. Have fun with it! Remember, this is your creation. You can even do a Hammerhead Shark, if you want!\n5. Finally, cut out 2 long banana shaped pieces of cardboard, the length of half the diameter of the shark body cylinder. Affix them above and below the desired opening to create the jaw. They are both affixed like a \"sad face\" shape, one at the very top of the cardboard cylinder - where the cardboard meets the balloon, overlapping a little at the top; the other one above that, directly taped onto the balloon - this creates the shark mouth. See the pictures for detail!\nWhen you are happy with the shark head, you are now ready to papier mâché!\nStep 3: Papier Mâché Fun!\nIt's time to lock in your shark shape! The first 1-2 layers are important as they give you a springboard to work off of, especially over the tip nose area made with balloon and newspaper (the cardboard cylinder is already pretty much shaped).\n1. Prepare your papier mâché paper - my paper of choice is torn brown craft paper, wet down and crumpled tightly to keep it moist, but wringing out all excess water. You can use thick brown shopping bags instead of store bought craft paper, but make sure remove all glue remnants and tear away all edges/seams of the bag. You want to prep a bunch into different sized pieces, so you don't run out in the middle of paper mâché-ing!", "636" ] ]

[ 103, 9501, 9384, 5273, 6540, 11115, 10657, 10057, 6704, 5560, 5371, 8570, 7808, 5440, 2032, 5222, 8832, 2106, 1640, 3365, 2449, 5676, 3187, 8558, 9008, 11218, 9732, 2635, 11347, 10105, 10178, 2582, 9128, 477, 9843, 5407, 10183, 6459, 2086, 9376, 8770, 8762, 8229, 5571, 3514, 10665, 4155, 10300, 4240, 8035, 4936, 3633, 228, 6567, 4881, 10568, 10659, 8465, 361, 5545, 5926, 7398, 1315, 4204, 6933, 6635, 1988, 7339, 637, 996 ]

[ [ "Creating Artificial Gravity In A Smaller Craft Where Energy Was Not A An Issue - Energy Required To Do So?\nIf you had a craft say the size of the spaceship in Guardian Of The Galaxy, big enough for a few rooms, etc. Now say you wanted to create gravity(artificial using centrifugal force) and energy was not a limiting factor(Yes this is definitely for fiction). Assuming if you are traveling towards some point at say close to c(The Speed Limit Of Causality in the universe) say .99*c (Where * is the multiplication operator under vector field hopefully * is not odd for multiplication operators. Anyway...)\nAnd we can assume the direction of overall motion has a unit direction vector D.\n0.99cD\nThen if you say wanted to produce a gravity roughly that of the moon, you could rotate perpendicular to D in a circle that had a radius of about say 6000m once a minute. Or say 3000m twice a minute etc.\nI assume that a wider circle would be advantageous as far as the feeling for the people on board such a craft not feeling nauseous.", "947" ], [ "I don't know which would require more energy to produce a large or smarler circle? I guess I could try to work that out, that is actually interesting as well to know the answer to that. But there is a different question I am confused about....\nSo now say if you have two ships exactly the same moving in the direct D, but one moving very close to the speed of light, and the other very slowly, not anywhere near speeds where relativity would start to show effects, again in terms of overall velocity over time... So ship A say has overall velocity...\n.99cD\nand B have a velocity of....\n0.000001cD\nWhat I am unsure about is to create artificial gravity in both these situations, meaning create a constant acceleration perpendicular to D and such that you are producing that circle of say 3000m radius. Is there a difference in the energy required for ship A to produce that rotating motion compared to ship B.\nI know alternatively if say the ship was itself had a radius of 3000m and just rotated then I believe the answer is that the energy required to produce the spin is the same in either case. But I was not sure if that is true for a ship that is rather moving in in a circle perpendicular to the overall velocity and must constantly create a changing direction of acceleration to produce that gravity.\nI guess I am asking if you are moving close to the speed of light relative to the stars/space around you, do you essentially act like you have more mass no matter which direction you intend to accelerate in, or do you only essentially see an increase in relative mass in the direction D if you were trying to change your velocity.\nAs you can tell I don't have a great deal of experience with complex relativistic motion, Lagrange transforms/mechanics are still a mystery to me. But even just a simple one-line explanation me in the right direction would very much appreciate As right now I don't even know where to find a good explanation of such a case?", "483" ], [ "What would happen if this FTL drive type concept were used in an atmosphere?\nSo I was working on this concept for a sci-fi story and in this universe it uses a \"warp\" drive.\nThe Genesis Field is a supra-dimensional field that causes spacetime to be created or destroyed (explaining dark energy), based on the pole of the field. This field used in an interstellar drive works much like the \"Warp\" Drive but it would not be called a warp drive. Basically it destroys space in front of it and creates space in back of it. Matter is not destroyed though. Matter that is in the space that is destroyed moves probabilistically to the space that was in front of or behind the space that was destroyed. If the matter is in the space being \"grown\" the matter moves in much the same way.\nHere's my question. In space, the density of matter is low enough to not cause a problem because any matter that gets into the field would not be enough to collect (at least I don't think so) and cause a problem either exiting the field at a rate equal or greater than the amount of matter that would enter. However, in an atmosphere this field would have all that air in it already and entering it from when it's traveling...\nWhat you have then is the field is moving forward at or above light speed with all the matter that was in it coming with it, creating an empty space where it was while simultaneously you have some of the air from where it moved to is moved to inside the field, assuming it's half in/half and half the volume of the field is filled with the ship, then the density of the air doubles...", "302" ], [ "while, again, simultaneously half the air from that volume it just pushed into is being moved forward possibly with a seeming velocity of c and this is all done at the speed of light. And then this is done continuously for whatever length of time the ship is in atmosphere or using this drive.\nWhat would the effect of this happening be? Since the air displaced by the field is not getting energy from this \"move\" I'm of the thought that any air that gets brought into the field would get just sorta start gathering in the front of the field.\nSo to clarify, there are sorta 3 parts...\n1. What is happening to the empty space left behind? Would air be rushing in? Would something like that be dangerous to Earth?\n2. What would the effect of the air density in the front of the field increasing so fast be?\n3. Similarly what would the effect of all that increase density air being pushed forward, but not having \"energy\" imparted into it be?\nWhen I first realize the consequences of this idea in an atmosphere my guess is that it would possibly cause the air to ignite, but I have no idea.\nEdit: There seems to be misunderstand from the 2 answer received. When the Space in front of the field is destroyed, the matter isn't so there needs to be someplace that it goes. This being the case it moves in any direction from where space was to where it is, to the closest it can reach. The result is not that half the matter moves to the other side of the ship's field, but rather goes inside the field, to the bubble volume that the ship is in.", "947" ], [ "Climate in an hypothetical Planet\nLet there be absolutely none, exactly 0 axial tilt. Let the earth's orbit around the sun be a perfect circle with 0 eccentricity and a surface to surface ( constant) radius equal to the harmonic mean of the surface to surface earth to sun distance through the past 800 years(an integral if time is thought to be continuous or measuring the distance every quantum, least increment of time, for 800 years). Let the sun be a perfect sphere and the earth be a perfect sphere(no mountains, cliffs, valeys, deeps) too. Let the angular speeds of earths movements(Revolution, Orbit, etc) be ever constant(a day of 24 hours and a Year of 360 years).", "188" ], [ "Let the consistancy of the Earth to the core be perfectly uniform with a perfectly uniform surface(allowing the exception for an amount of rivers running through perfectly straight lines of longitudes with a symmetric distribution between the latitudes so the human civilisation could have water and thrive). Let the consistancy of the rivers/ocean and atmosphere be perfectly uniform with a breathable partial pressure and a tolerable total pressure.\nI tried to make the climate as uniform as possible and not simply remove Milankovitch Cycles. I do not have any ideas how the climate could be more uniform if anyone has any ideas I would be happy to think about them.\nNow to my question\nHow will Earth's climate be and how will that climate affect human life and civilisation?\nI think that the poles will shrink as there would not be any winter, the variance would be minimal and largely due to longitude difference and not due to latitude differences(proximity to the rivers could play a minor roles), the average temperature would increase as less heat will be radiated back to outer space and more of it kept on earth(Radiation of Black Body). I want my hypotheses confirmed and a way to imagine how the climate would be. As for the consequences to life and civilisation I have no ideas.\nN.B I tried to ask a similar question on Earth.Sciences because I thought it belonged to climatology and planetary science but they refered me to worldbuilding.", "591" ], [ "Stellar Mapping and Coordinates\nWhy are the Galactic Coordinates not aligned so that the Axes go through the Long Bar Y-axis aligned to it's longer side, positive with Sol, and the X-axis align to the center of the short length with Sol being in the negative? Z should obviously be on the galactic plane where it generally is I think...\nI'm curious about whether there is a reason we shouldn't align it like this? It seems to make the most sense to me where as the current system, while I understand it, to me is just to Earth-centric, especially when we have something that stands out so much on the galactic scale you could use to figure out where you are with where as Where Sol is being 0,0,0 isn't really helpful to anyone unless you're already on Earth ^.^\nThe other part of my question is less \"real\" and more of a \"I would like to know if there are any problems with doing this that I am unaware of\" thing...\nThere are 3 question areas...\n1\nI use a unit I call a Lida, It is 24 terameters long and roughly equivalent to a Light Day. On this map distances will be measured in Lida, more specifically, KiloLida. 1 Sector = 20 kL^3\n1 Block = 200 kL^3\n1 Grid = 2,000 kL^3\n1 Octant = 20,000 kL^3\nEach of the bigger areas contain 1000 of the next smaller unit down and can easily be referenced by a 3 digits. So if I said Grid 346 that would reference the Grid in that Octant where each of those digits are xyz starting from the the Galactic Center. Lower numbers are always closer, Higher are always further from the Galactic Center.\nWhy not use parsecs and light years? They're really not practical to use. Likewise, AU are weird, and other units you either end up with very long numbers or poor conversions. Also with this unit I find it very easy to work out distance and time in my head.", "24" ], [ "The answer is 1.07% off, but that's not really an issue when you're not trying to be 100% precise.\nWhy use 20kL rather than 10kL or 1kL not many stars in that volume from what I looked at before so it makes sense to use that as division and it also divides up nice to the higher divisions.\n2\nI use another unit.\n1 brut = 1x10^19 kg\nThe largest reason I'm using this is that scientific notation doesn't work in emergencies or common parlance so it makes sense to me to have a larger base unit when dealing with these larger scales. 1x10^19 kg, if I remember right (cuz I came up with this a few years ago and haven't used it since), comes from when the reference point numbers on wiki for scale started getting fishy looking to me. Not a hard science thing, but seemed like a good place to have something like this.\n3\nThis is the way I label Stars, planets, moons, etc... because it makes sense. I keep saying that, but you know, it's true ^.^\nSO I - Star (or black hole)\nSO II - Spheroid\n--->Brown Dwarf (Star?)\n--->Gaseous Spheroid - 12,000+ km radius and above (Most of it's size is from gases)\n--->Terrestrial Spheroid - 1,500 to 12,000 km radius (Has a rocky mantle)\n--->Icey Spheroid - 200m to 1,500 km radius (Has an ice-water mantle)\nSO III - Debris\n--->Asteroid - Comprised mainly of rock\n--->Comet - comprised mainly of ice-water\nChild Star (?) - SO I that orbits a SO I\nPlanet - SO II that orbits a SO I\nMoon - SO II that orbits a SO II\n??(currently also called a moon it seems) - SO III that orbits a SO II\nSO means Stellar Object. both SO and Spheroid are kinda bad names considering nothing but stars are Stellar and stars are Spheroids, but whatever, I think it gets the point across. Though I wish I could think up something better.\nAnyways, do any of these 3 things create problems that I don't know about or that could cause a problem that I possibly can't see due to being a pleb in these matters?", "24" ], [ "What @A.C.A.C is getting at is (I think) is speed relative to what?\nThe Earth moves with a speed around the Sun, but that is not an absolute speed, that is a speed relative to the Sun. The Moon has a speed that it orbits the Earth, and another at which it orbits the Sun. I think you are attempting those two together, but those are two different references. You can somewhat do so, and say that you come up with a speed that the moon is orbiting the Sun.\nWe will ignore that in reality the Earth also orbits the Moon part as it it relatively unimportant here, the Moon is at times effective going around the Sun faster than the Earth, but only while its orbital direction matches the Earth's orbital direction around the Sun.", "319" ], [ "Half the time it does not, half the time it is in the other direction, which means at those times it is orbiting the Sun slower than the Earth. If you are talking average speed relative to the Sun, then the Moon has the same average orbital speed on the Sun as the Earth, however, because it is also orbiting Earth it ends up with a slightly longer orbital path, so a slightly higher average orbital speed relative to the Sun.\nBut the, the entire Solar System is also moving in the Galaxy because it is spinning at a much higher speed than the relative orbital speed of the Earth or Moon. Is that in a direction that adds to of subtracts from the Orbital speed? Oh, Wait, not only is the Galaxy is also moving through space at a much higher rate as well, that really makes it complicated in deciding, relative it what is anything moving faster than anything else. You need to set a point of reference first.\nETA: This link may help to the clarified question: https://en.wikipedia.org/wiki/Talk%3AOrbit_of_the_Moon\nThis shows a highly exagerated scale what the Earth-Moon orbit around the sun looks like in this image:\nNote that the smooth orbit we think of as Earths is not either, it is a two body system orbiting the sun and the moon and Earth actually orbit a center of gravity between them, it is just much closer to the Earth. The picture again is grossly out of scale.", "393" ], [ "Using relative velocity between two frames and the time elapsed between events in one frame to find the time elapsed/event separation in the other\nQ from text: A second transporternaut is beamed to a much more remote galaxy that is moving away form Earth at .87c. This time, too, she stays in the remote galaxy for one year as measured by clocks moving with the galaxy before returning to Earth by Transporter. How much has the transporternaut aged when she arrives again back at Earth?\nIn this question, of which this above is part e, the transporters send the person as data at light speed form place to place, and disassembly and reassembly time is negligible. From a previous part, I found that she will not age on the trip there or back, as she is travelling at the speed of light, and the interval for her is 0 (her time elapsed as seen form earth is, say, 2E6 ly to get to andromeda, but andromeda is 2E6 ly away, so I = (t^2-d^2)^(0.5) = 0).\nAll her aging, then, is on this galaxy, for one year galaxy time. I want to find out how long that is in Earth time. In the galaxy's frame, the event of her arriving and leaving occur at the same place, and since one year elapsed the interval is 1 ly light travel time.", "272" ], [ "This must be the same as calculated form Earth. I was trying to find the distance, as seen form Earth, that the galaxy moved. This would be the separation between the events of her arrival and departure form the galaxy, as seen form Earth, and with this and the interval I could find the time elapsed between the events as seen form Earth.\nI could use the relative speed between Earth and this galaxy, to find the distance between them. But what frame will I be finding this distance in? Example, If I use the time elapsed as 1 year, I get .87 ly distance, but this is as seen from this new galaxy. From Earth it wasn't a year elapsed, which is the point to begin with. If observers both on earth and on the galaxy see the same relative velocity between them (I assume they do), but they can experience different amounts of time being elapsed from the arrival and departure of the transporternaut, they must find different distances moved by the galaxy in the meantime. So I shouldn't be able to use the relative velocity, which is the same measured in either frame, and the time as measured in the galaxy, which differs from that measured on Earth, to find the distance as seen form Earth, should I? If I can, how comes? What other info do I have that could solve this problem?\nIt seems like I have both the time elapsed and the distance the Earth moved away, as seen form the galaxy, whereas I ahve none of this info for the observer in Earth's frame.\nIf I use the .87 ly as the distance between events, seen on Earth, and the interval as 1 ly, I get 1.3 ly time elapsed, so 1.3 years aging.", "272" ], [ "The Logic Problems of Black Holes\nAs I always preference my questions, I am not a scientist or student. I am an engineer who loves physics.\nIt is my understanding that, there are 2 competing thoughts behind what a black hole is. Standard Description – Is that a stellar core collapses under its own weight when it begins to fuse iron. It shrinks to a point of infinite density and an event horizon is formed. Time splits from space just below the event horizon. Matter falling into the event horizon will eventually meet the singularity.\nThe second description is like the first, except that matter never falls below the event horizon and piles up on it. (This is due to time ending at the event horizon). The black hole and event horizon expands because of this shell of material on it.\nBoth descriptions are illogical. They might make sense from a mathematics point of view, but they have problems from a purely logical point of view.\nStandard Description 1. Density - Let’s say we have a BH at 10 solar masses. If I push another solar mass of material into the event horizon, how can something that was infinitely dense, become even more infinitely dense? 2. Size – How can matter collapse to a singularity… (Now I understand that it is a mathematical singularity which means we have pushed physics to its breaking point…) Logically you cannot be infinitely dense, and infinitely small.", "43" ], [ "You can be one of the other, but not both. If you are infinitely dense, any matter falling onto you would have to pile up around the singularity as it cannot be squeezed any further. If you are infinitely small (let’s say a Planck Length in size), then you cannot be infinitely dense, as new material must be squeezed into this Planck Length as well. 3. Energy – I would expect that as the quarks are destroyed in the collapse, they would give off a TREMENDOUS amount of energy. Where does this go? Why does it not push back against gravity blowing the stellar core apart? (I do not think there is anything that keeps the “singularity” from being pure energy is there?) 4. If you have an infinitely dense, infinitely small singularity, how does the event horizon grow?\nSecond Description 1. If time ceases, just at the event horizon and all matter deposited on the event horizon forms shells around it why is it not reflective? It would no longer be a black body as matter on the top of the shell would be further away than the event horizon and the escape velocity would be less than the speed of light.\nTo me this is the easiest to get around. Time does indeed stop just “BELOW” the event horizon. Matter does not collapse into a singularity and therefore is not infinitely dense. As matter is drawn into the event horizon, it piles up on the core and enlarges the event horizon. (Think of a glass that as you add water, keeps expanding.) However, I don’t think this is mathematically supported.\nI am sure there other paradox’s surrounding black holes. These are the ones that have made me curious.", "334" ], [ "Theoretical question on frames of reference\nSome friends (all engineers - not scientists) watching Star Trek and discussing the science behind it. Not whether warp drive or aliens or anything like that were real.... No our discussions were on the frame of reference a ship at \"warp\".\nWe understand that <PERSON>'s theory of special relativity states that energy and mass are interchangeable, and speed of light travel is impossible for material objects that weigh more than photons. This can theoretically be solved by warping space to move an object instead of increasing the kinetic energy of the object to do so.\nLet's say NASA develops a ship using a warp drive. Space time is warped. We want to travel to Jupiter. So we point the ship at Jupiter and press start.\nFrom our pilot's point of reference is he moving? He can see Jupiter getting larger... but would he feel the acceleration....space is moving, but would he simply feel like he is sitting still? If a person was outside of the warped space, would they see the ship move? If space is warped and space is moving the ship, would the ship be red/blue shifted as it passes?\nThe final question we had was does our pilot have inertia? The question arose from our theoretical pilot stopping the ship....", "275" ], [ "I argued that as the ship isn't physically moving, and it has no inertia. My friends argued that the space moving supplied inertia to the pilot. Simply pressing stop would cause the ship to pancake.\nOn a side note... If my pilot dropped a ball out of the ship as it was moving, what would happen to the ball? Would it simply stop in mid-space, would it move in the same path as the ship or would it suddenly feel relativity and be crushed into a very tiny black hole.\nQuestions: 1. If we are warping space, what does our astronaut feel? Does he feel like he is moving or not?\n1. If space is warped, would the ship be red/blue shifted?\n2. Does the warping of space supply inertia to our pilot? Or can you simply turn off the warp field when you arrive at your destination....\nI know this isn't very scientific... Please don't flame me because of the question.... just trying to get a real answer to a theoretical question.\nThanks", "621" ] ]

[ 3901, 5424, 9585, 7168, 3505, 2056, 5025, 4577, 9917, 142, 468, 3905, 6191, 1471, 4291, 4005, 9106, 864, 10718, 5336, 11142, 10577, 9241, 4150, 9831, 10610, 5378, 9079, 3029, 6530, 7262, 3742, 1537, 10440, 8432, 9593, 1109, 5417, 7785, 1649, 9380, 1770, 2173, 8811, 8825, 1707, 10542, 8129, 3314, 2957, 1713, 3554, 1701, 636, 3046, 5173, 10000, 5596, 7738, 5140, 9399, 7312, 2169, 10878, 8059, 10342, 2925, 5748, 300, 8160 ]

[ [ "Dutch Apple Pie\nIntroduction: Dutch Apple Pie\nEasy and delicious apple pie recipe! It is HUGE, so you can serve it for your family and friends. A lovely project for leftover apples. Holidays or weekend will be better with this European apple pie.\nTraditional Dutch Apple Pie was first published on our blog. Check it out! You can read more about its origins and which apples to choose for baking.\nThis pie is so comforting and your kitchen will smell amazing with apples and cinnamon!\nSupplies\nFor the pastry:\n* 1/2 cup sugar\n* 2 1/3 cup flour all-purpose\n* 3/4 cup butter cold and cubed\n* 1 egg big\n* 2-3 tbsp water\nFor the filling:\n* 11 small apples\n* 1 tbsp lemon juice freshly squeezed\n* 2 tsp cinnamon ground\n* 1 tsp flour all-purpose\n* 1/2 cup sugar\n* 4 tbsp semolina\n* 1 egg yolk for brushing the top\nEquipment:\n* 8 inch spring form pan or pie form\n* bowls for mixing\n* pastry decorator knife (optional)\n* foil for baking\n* spoons or spatula\nStep 1: Make the Pastry\nCombine sugar and flour in a bowl.\nAdd few butter cubes and press them into the flour-sugar mixture with two forks or pastry maker. Add all butter cubes, pressing them into the flour.\nAdd an egg and water. Combine wet and dry ingredients.", "763" ], [ "Form the dough with your hands.\nWrap the dough in plastic, leave in the fridge for at least 1 hour.\nStep 2: Prepare Filling\nMeanwhile prepare your apples for the filling. Wash them, peel and remove the core with seeds.\nThinly slice apples and transfer them to a large bowl.\nAdd freshly squeezed lemon juice.\nAdd cinnamon, sugar, flour and combine until all apples are covered.\nStep 3: Form the Pie\nRemove the dough from the fridge, unwrap it and slice in half.\nForm the ball from one half, and roll the thick round for the pie form.\nPlace the bottom pan on the dough and cut the round for the bottom of the pie. Add it to the bottom of spring form pan pan.\nFrom the leftovers make 2-3 pieces for sides and put them in the pan, pressing to the sides.\nMake sure to press the stitches well to hold the filling! Don't make it too thin.\nStep 4: Add Filling\nSprinkle semolina on the bottom of the pie.\nAdd apples until top.\nStep 5: Make the Top of the Pie\nFrom the other half of the dough, form the round and roll it.\nUsing the pastry decorator knife make decoration. Alternatively, cut the 1/2 inch lines and place them on top of the pie. Press the decoration to the sides of the pie.\nBrush the top of the pie with egg yolk.\nStep 6: Bake and Serve\nCover the top of the pie with foil, bake for 30 min in the oven, preheated to 356 F.\nRemove from the oven, remove the foil and brush with leftover egg yolk.\nBake the pie uncovered for 30-40 min. The pie is ready until apples are softened and the top is browned.\nLet it cool in the pan, then transfer it to the serving plate.\nCut into pieces and serve with whipped cream or ice cream!", "891" ], [ "Halloween Pot Pie\nIntroduction: Halloween Pot Pie\nSavory Halloween pot pie from scratch. Jack-o'-lantern face will make it fun decoration on your holiday table!\nI will show you how to make an easy pie crust from scratch with only 3 ingredients.\nAnd also a delicious chicken and vegetable filling for the pot pie to die for! Delicious dinner idea for your family, a classic turned into Halloween chicken pot pie.\nThis Spooky Jack-O’-Lantern Chicken Pot Pie was first published on our blog. Check it to find more tips and tricks on how to make a pie crust.\nFollow this easy step-by-step recipe:\nSupplies\nFor the filling:\n1/3 cup unsalted butter\n1/3 cup chopped onion and garlic\n1/3 cup flour\n1/2 tsp salt\n1/4 tsp pepper\n1 3/4 cup chicken broth, low sodium\n1/2 cup milk\n1 1/2 cup cooked chicken\n2,5 cups vegetable mix (chopped potatoes, carrot and peas)\nFor the pie crust:\n2 1/2 cups flour\n1/3 cup salted butter\n5 tbsp water\nYou will also need a rolling pin and 11 inch pie pan\nStep 1: Cook the Filling\nStart with the filling, because it needs time to cool. You can make the filling ahead of time and store in the fridge up to 2-3 days.\nAdd butter to the hot pan.", "851" ], [ "Add chopped onion and garlic and cook, stirring, for a few minutes.\nAdd flour, salt and pepper and cook stirring 30 seconds.\nAdd chicken broth and milk.\nAdd mixed vegetables and cooked shredded chicken.\nCook the filling until it thickens, about 5 minutes.\nLet it cool completely before adding to the pie crust!\nStep 2: Make the Dough for the Pie Crusts\nYou can skip this step, if you have store-bought pie crust. But this is such an easy pie crust recipe!\nFirst, prepare all ingredients. Put flour in a large bowl, add cold butter, cut into cubes. Press with your fingers until you have a crumbly mixture.\nGradually add cold butter and knead until it comes together.\nDivide the dough into 2 discs (one larger than another), wrap each in plastic and leave in the fridge for 10 minutes.\nStep 3: Roll the Pie Crust\nUnwrap the larger disc and place it on the floured surface.\nDust the rolling pin with flour and roll the round bottom crust.\nCarefully roll the dough on the rolling pin to transfer to the 11 inch pie pan.\nPoke the holes in the bottom of the crust and put it in the fridge for 30 minutes. This will prevent the crust from shrinking.\nStep 4: Make the Pie\nAdd the filling to the pie pan with pie crust.\nRoll the second disc and add it on top of the pie.\nPress the edges with your fingers and cut excess edges.\nUsing a sharp knife, cut the face of Jack-o-Lantern.\nBrush the top of the pie with beaten egg.\nStep 5: Bake the Pie and Serve\nBake 30-40 minutes in the oven, preheated to 425 F /220 C.\nLet it cool 10 minutes before serving and enjoy!\nYou can store it in the fridge for 3-4 days.", "702" ], [ "Banoffee Pie\nIntroduction: Banoffee Pie\nBeautiful and simple sweet pie that every family member will enjoy! Because who doesn't love cookies, caramel, banana, cream and chocolate? Amazing combination for a sweet tooth!\nIt's an English dessert with flavors that everyone knows. If you haven't tried it, you should! Keep in mind that you will need more that one slice of this delicious pie.\nThis amazing pie was first published on our blog as No Bake Banoffee Pie. You can read on our blog, why this pie is called Banoffee.\nThere is no baking required to make this pie. It's an easy pie idea, when you want to have a treat or sudden guest arrives.", "290" ], [ "One of our favorite no bake pies!\nSupplies\n8 inch / 20 cm spring form pan\nfood processor or a bag + rolling pin\n230 g plain biscuits, cookies or graham crackers\n150 g melted butter\n1 can dulce de leche (caramelized or boiled condensed milk) (397 g)\n2 big bananas\n300 ml whipping cream or 1 1/4 cup\n1/2 tsp vanilla flavored instant coffee\n1 pack cream stabilizer 15g\n1/2 cup or 90 g dark chocolate for decoration (optional)\n1 tbsp crushed hazelnuts (optional)\nStep 1: Banoffee Pie Base\nCombine the crushed biscuits or cookies with melted butter.\nPress to the bottom and sides of the spring form pan or pie pan.\nUse food processor to crush the cookies. Alternatively, put cookies in a sealed bag and crush with the rolling pin.\nLet the base set in the fridge for 1 hour.\nStep 2: Pie Filling\nFill the bottom of the pie with caramelized condensed milk or Dulce de Leche.\nPlace the slices of banana on top.\nWhip the cream with stabilizer and coffee, using electric mixer until stiff peaks. You can add a little bit sugar here, but Dulce de Leche and banana together are very sweet !\nPut the whipped cream on top of the pie.\nPut the pie in the fridge, while making decoration.\nStep 3: Decorate the Pie\nMelt 3/4 of the chocolate on a double boiler (a pot with simmering water and a heat-proof bowl placed on top).\nMake sure the top bowl doesn’t touch the water!\nWhen it is almost melted, remove the bowl from heat and add remaining chocolate. Stir until melted and cooled.\nThis process is called tempering, you can see our instructable on how to temper chocolate.\nPour chocolate on the tray or plate, layered with parchment paper and let it cool completely. Cut different shapes and leave aside.\nAlternatively, just grate some chocolate on top of the pie!\nCut the hazelnuts in half.\nStep 4: Decorate the Pie\nInsert the chocolate decorations in the pie and sprinkle crushed hazelnuts.\nCut the banoffee pie and enjoy!", "851" ], [ "Pumpkin Biscuit\nIntroduction: Pumpkin Biscuit\nHi.\nJumping on the departing train… :) I'd like to share with you a recipe of the fragrant, delicious, bright, and insanely tasty pumpkin biscuit for your cakes. That's biscuit is a good illustration of the autumn spirit.\nSo let's start\nSupplies\n* Mixer\n* Bowls\n* Baking ring ≈ 18 cm in diameter\n* Aluminum foil\n* Silicone spatula\n* Oven\nStep 1: Preparations\nBefore we start you have to prepare or buy in the nearest grocery store the pumpkin puree.\nTo make the pumpkin puree we'll need to peel and then chop the pumpkin to the cubes with sides approx 2cm.\nPlace it in the microwave for about 10 min with 800W power until it'll appear to be soft. Blend the pumpkin.\nDone.\nStep 2: Ingredients\n* 230g - pumpkin puree\n* 140g - egg whites\n* 105g - egg yolks\n* 215g - sugar\n* 180g - flour\n* 40g - corn starch\n* 8g - baking powder\n* 3g - turmeric\n* 2g - garam masala\nStep 3:\nTake the flour and add corn starch, baking powder, turmeric, and garam masala into it and mix until it'll be uniformly mixed.\nNote: On this step, you can start preheating the oven to 170 ˚C.\nStep 4:\nAdd 1/2 of the sugar into the egg yolks and mix them. Then add the rest of the sugar into the egg whites and mix them for hard peaks.\nStep 5:\nTake the mixed egg yolks and add the pumpkin puree. Mix it.", "305" ], [ "Add spiced flour and mix.\nStep 6:\nAdd 1/3 of the mixed egg whites into the Egg yolks mixture and mix until the mixture will be uniformly mixed. Continue mixing and add the rest of the egg whites, and mix it well.\nStep 7: Prepare the Form and Bake It!\nTake the baking ring and wrap it with a sheet of thin aluminum foil from the bottom. Place it on the baking sheet and pour the dough into the baking ring.\nBake in the preheated oven for ≈15-20 minutes.\nOnce done, take it off from the oven and let it chill without removing from the form. When the biscuit cooled down take the biscuit from the form and cut it to make 3 slices.\nNote: Do not open the oven's door while baking is in progress, or the biscuit will collapse.\nStep 8: Wrapping Up\nAfter connecting your favorite filling with these biscuits you'll get an amazing cake. As for me, I really like cream cheese.\nPlease share your results.\nEnjoy!", "891" ], [ "Chocolate Cookies With Maraschino Cherries\nIntroduction: Chocolate Cookies With Maraschino Cherries\nEasy and sweet cookies that are perfect for sharing with your family and friends! Cherry and chocolate combination will make anyone crave more. This is especially good for upcoming holidays like Christmas.\nThey are made for chocolate lovers, who don't have time to make a chocolate cake. Cookies are easy to make and they bake only 10 minutes.\nThese cookies will make you life sweeter and any day brighter.\nHighly recommend them to store in the fridge and have one on a bad day! Well, they make a good day even better!\nCrispy outside and chewy inside. Perfect treat to have with tea, coffee or milk!\nTempting Chocolate Cherry Cookies were first published on our blog.\nSupplies\n1,5 cup flour\n1/4 cup white sugar + 1/4 cup brown sugar\n2/3 cup unsweetened cocoa powder\n1/4 tsp salt\n1/4 tsp baking powder\n1/4 tsp baking soda\n1/4 tsp vanilla powder or extract\n1/2 cup butter\n2 medium eggs\n1 tbsp maraschino cherry liquid, mixed with powdered sugar to syrupy consistency\n1/4 cup melted chocolate\n1/2 cup milk\n1 cup maraschino cherries\nextra crushed almonds for serving\nYou will need hand mixer, scoop, spatula and baking tray with parchment paper\nStep 1: Prepare Dry Ingredient\nIn one bowl mix all dry ingredients with a spoon: flour, cocoa, all sugar, baking soda, baking powder, vanilla powder and salt.\nNo need to sieve them, just combine well.\nStep 2: Mix Butter and Eggs\nIn another bowl, beat butter with a hand mixer, scraping the sides until pale.\nAdd eggs and mix until combined.\nGradually add few tablespoons of dry ingredients. Mix until just combined.\nStep 3: Prepare the Cookie Dough\nSwitch to the spatula.\nAdd half of dry ingredients and mix with a spatula.", "851" ], [ "Add milk, so it will be easier to mix together.\nAdd remaining dry ingredients and mix until combined.\nAdd maraschino syrup and melted chocolate. Combine until smooth.\nStep 4: Chill in the Fridge\nCover the bowl with plastic wrap and leave in the fridge for at least 30 minutes or 1 hour.\nThis part is essential, so don't skip it! Chilling the cookies will make them more flavorful and they will spread less, while baking.\nStep 5: Make the Chocolate Cookies\nScoop the balls to the baking tray, layered with parchment paper.\nYou can roll the balls in your palms. Dust the hands with extra cocoa powder, so it will be less messy!\nPress the centre of each cookie with your thumb.\nPut cherry on top of each chocolate cookie.\nStep 6: Bake and Decorate\nBake 10-15 minutes in the oven, preheated to 356 F / 180 C.\nThe more you bake, the crispier cookies will be. But the cherries will become more dry, too.\nLet them cool on the wire rack. Sprinkle with crushed almonds.\nEnjoy!\nThey will keep in the fridge up to 6 days or 1 day at room temperature.", "195" ], [ "Pull Apart Pizza Appetizer\nIntroduction: Pull Apart Pizza Appetizer\nDifferent take on a regular pizza, made with store-bought puff pastry, perfect as a sharing appetizer or full on meal. Make sure to cut all ingredients into tiny pieces, that way you will get more flavor in each bite.\nStep 1: Ingredients\n* Two sheets of puff pastry\n* 1 cup pizza sauce (from a jar or home made; I make mine by frying a small shallot with two minced cloves of garlic, salt, pepper, dried oregano and 1.5cup of passata, I cook it until sauce thickens and reduces to 1 cup)\n* 0.5 cup finely chopped olives\n* 100g finely chopped ham\n* 150g finely grated cheddar or mozzarella cheese\n* 300g mushrooms for mushroom paste\n* small egg for egg washing\nMushroom paste sound a bit odd, but believe me, it's great. Use a food processor to grind them into tiny pieces and then cook them in a frying pan with 1 tablespoon of olive oil and a dash of salt (medium heat). Continue cooking until all water evaporates and you are left with mushroom paste. Or, you can just chop mushrooms into small pieces and fry them until all water is removed.\nStep 2: Pastry\nCut both pastry sheets into rough circles, reserve the leftover bits.\nStep 3: Filling\nSpread pizza sauce, olives, ham and cheese onto the first pastry circle.", "265" ], [ "Leave about 1cm border for an egg wash. Spread mushroom paste onto the second circle.\nStep 4: Twisting\nBreak an egg and whisk it with one spoon of water, spread it around the pastry border with a pastry brush. Place the second pastry circle on top of the first one and seal the edges with your fingers. Use a glass to lightly score a circle in the middle and cut the pastry into 16 even pieces. Pick each piece and twist it twice in the same direction. Egg wash the whole pie and bake at 200°C (400°F) for 22-25 min.\nUse leftover filling and pastry cut offs to create tiny pizzas and bake them in the oven at the same time.\nLet it cool enough to handle and serve with ketchup squirted in the middle of the pie.", "69" ], [ "Easter Banana Bread\nIntroduction: Easter Banana Bread\nEasy banana bread is a lovely Easter treat to serve for your family. It is good for sharing around the table, super moist and delicious. Vanilla cream topping makes it more festive!\nBanana Carrot Bread Recipe was first published on our blog.", "290" ], [ "Check it to learn more tips on how to make and store it.\nI'm sure everyone will love a piece of moist and crunchy Easter banana bread. And it is a good way to use leftover brown spotted bananas and add veggies (carrots) to your picky toddler diet!\nSupplies\n2 eggs\n½ cup vegetable oil\n3 bananas ripe\n¼ cup brown sugar\n1 tsp vanilla powder or essence\n¾ cup oat flour or quick oats\n1 tsp baking soda\n1 tsp baking powder\n1 tsp cinnamon\n½ tsp ginger\n¼ tsp nutmeg\n1 ¼ cup whole wheat flour\n2 big carrots shredded\n½ cup walnuts chopped + extra for decoration\n1 tbsp Vanilla cream powder for cake (I used Dr.Oetker)\n1 cup milk of choice\n1 tbsp dried carrots optional\nEquipment:\n* bowl for mixing\n* 1 spatula\n* 1 Loaf pan\n* parchment paper\n* Oven\n* Whisk\n* fork\n* off-set spatula or spoon\nStep 1: Make Banana Bread Batter\nMash banana with a fork, then in separate bowl whisk eggs and oil until foamy.\nAdd egg mixture to mashed banana.\nAdd wheat flour and oat flour, fold in with a spatula.\nAdd sugar, baking soda, baking powder, vanilla and spices. Mix until everything is incorporated.\nFinally fold in grated carrots and walnuts.\nStep 2: Bake the Bread\nAdd batter to the loaf pan, lined with parchment paper.\nBake 25-30 min in the oven, preheated to 190 C / 375 F, until inserted toothpick comes out clean.\nLet it cool completely before removing from the pan.\nStep 3: Make Topping\nWhip milk with vanilla cake cream powder (according to instructions on the package).\nApply cream to the bread with an off-set spatula or back of the spoon.\nDecorate with walnuts and dried carrots (optional).\nYou can also decorate with whipped cream cheese instead or drizzle with chocolate!\nStep 4: Cut and Serve\nCut the bread into thick slices and serve for your family!\nEnjoy!", "305" ], [ "Spiced Cake\nIntroduction: Spiced Cake\nCongratulations Instructables with your 1000th contest! This cake recipe is for you but unfortunately you have to bake the cake yourself :) This cake is a variation of a recipe that is more than 100 years old, my grandmother already baked it, and is very well known in my country. The original recipe is also known as 'the 250 gram recipe’. Very simple, cannot fail, and very easy to remember: just 250 grams of everything. Well almost, only salt is a pinch. And best of all with this old recipe you can make endless variations.\nBecause we are crazy about spice buns I thought that this spice mix, named ‘Rommelkruid’ in Dutch, would also be tasty in a cake, so this is a new variation. We also like dried fruits so I also added raisins and candied citron. This cake is now a favorite and in high demand.\nSupplies\nFor the Rommelkruid (this is more than necessary for a cake) *\n3 tsp aniseed\n3 tsp fennel seed\n1.5 tsp allspice\n1.5 tsp liquorice\n0.5 tsp cloves\n0.5 tsp mace\n0.5 tsp nutmeg\n0.5 tsp white pepper\n0.5 tsp black pepper\n1.5 tsp cinnamon\n0.5 tsp cardamom\n1 tsp sandalwood (option)\n0.5 tsp garlic powder\nMix all spices and herbs together and store in a glass jar.\n* All herbs and spices are ground.\nFor the cake\n* 12g Rommelkruid\n* 1 g of salt\n* 250 g raisins, candied citron / or other dried fruits (I chose 150 g raisins and 100 g candied citron)\n* Some water, rum, or vodka to soak the raisins\n* 250 g real butter\n* 250 g of sugar\n* 250 g sieved self-raising flour\n* 250 g egg (5 -medium-eggs of about 50 g)\n* some extra flour for the dried fruit\n* some butter or Crisco to prepare baking pan\nTools\nhand or stand mixer\nSpatula\nKitchen scale\nBowls\nKnife\nBaking tray\nBaking paper\nSieve\nSpoon\nStep 1: The Preparation\nWash the raisins and soak them in water, rum, vodka or whatever you prefer for an hour or two.\nTake the butter and eggs out of the fridge and let them come to room temperature. For another project I cleared out eggs, this egg pulp I use for the cake. Instead of egg by egg I now add sauce spoon by sauce spoon of egg pulp. It is important that all ingredients have the same temperature. Uneven temperature is one of the reasons that a batter can curdle. If this happen, place the bowl with batter in a bowl of warm water and keep stirring until a homogeneous mass is formed again.\nPrepare the baking tray, grease it with some butter or Crisco and cover with baking paper.\nWeigh all ingredients\nPreheat the oven to 160 ° Celsius\nStep 2: The Batter\nPut the butter and sugar in the mixing bowl and mix for 4 minutes. After 4 minutes, add the spice mixture and salt. Mix again for 4 minutes and fold in the butter mixture a few times in between so that everything mixes well\nMeanwhile, drain the raisins in a sieve.\nNow add an egg and mix until the egg is completely absorbed.", "305" ], [ "Then add the next egg and mix again until it has also been absorbed. Repeat this step until all the eggs are gone. Adding an egg before the other egg isn’t fully absorbed increases the risk of curdling. Stop mixing once the last egg is fully absorbed. The mixer is no longer needed.\nAdd a spoonful of flour to the drained raisins and also add the candied citron. Stir this so that all fruits are covered with a layer of flour. The flour will prevent the fruits from sinking to the bottom of the cake during baking.\nFold the sieved self-raising flour through the batter by hand. Do this slowly so that the whole batter remains as light as possible. The cake batter is now ready.\nFill the baking tray with about 2 cm of batter and sprinkle about half of the fruit mixture on top. Add about 2 cm of batter again and on top of that the other half of the fruit mixture, close with the last batter.\nPush the spatula upright into the batter about every few cm and pull it up again. Continue like this throughout the batter. In this way you pull the fruits through the batter. This will make them sink even less than when you stir the fruit into the batter. Finish by smoothing the batter.", "891" ] ]

[ 9077, 5857, 67, 9823, 11318, 6862, 5762, 7741, 365, 9770, 6077, 8865, 1516, 6011, 6434, 2077, 3043, 2856, 11239, 1949, 5588, 11287, 8014, 9281, 9941, 4040, 7512, 8799, 4510, 5877, 11418, 1901, 860, 3690, 2282, 10014, 1246, 6074, 3772, 1911, 10512, 8357, 4239, 9463, 7997, 10631, 1989, 3276, 9439, 4947, 9006, 488, 5129, 2759, 1123, 10372, 10581, 5172, 10355, 9567, 2171, 9825, 11182, 8642, 2409, 7060, 881, 1585, 8914, 925 ]

[ [ "Someone had questioned the lack of reviews on this one, so I thought I might try my hand at a quick once over.\nFirst, the obvious stuff. This is an expansion so I won't go into the basics of Pandemic, only how this might change the experience.\nNow, to begin with, let's go over what ITL brings to your table. You get:\n4 new roles\n3 new events\n2 new virulent strain epidemic cards\na new mutation challenge (2 cards & 12 more purple cubes)\nnew cards & research stations for a new 'Team play' option\na new solo play option\nand finally, the In the Lab challenge, consisting of an additional board, 14 sequencing cards & 5 spiffy new cure vials.\nOverall, a pretty nice set, now for more details.\nFirst, the new roles. You only get 4, but they're pretty useful ones, and honestly if you also have OTB, you now have tons of options. I would point out that these 4 are by no means limited to ITL play, they should be nice options in all variants.\nSecond, the new events. Again, not a ton, but very nice ones that aren't limited to any particular variant. They match the ITL challenge thematically, but by no means would be out of place in other games.\nI like the additional cards for the Virulent Strain challenge, though I admit I rarely play it. If you like the increased difficulty and want more variation, this will help.\nI find the new way to play the Mutation challenge (Worldwide Panic, if I recall the title correctly) more to my liking than the original challenge. Essentially, the mutation starts with a wider area affected and spreads quicker, but I think this is actually a good thing if you combine it with the ITL challenge.\nTeam play is a nice semi-cooperative style where players are 2 or 3 teams trying to gain prestige for curing or eradicating diseases first. The loss conditions still apply to everyone, so I would assume some cooperation would still be wise, but it is limited. I found this part to be a decent option for play, but it didn't really thrill me. Much like the bio-terrorist from OTB, I can see it being a change of pace but not really what I would look for in a game of Pandemic.\nThe solo rules are an interesting take, if only because I would bet most Pandemic players already play it solo as is. It allows you to take 1 role and play a modified game with a CDC helper that takes very limited actions to assist you. I think this might grow on me over time, having only tried it once, but I still prefer to just control multiple roles when I play solo. Still, I do love options to keep things fresh, and this is a pretty good one.\nI've saved the biggest thing for last.", "699" ], [ "The Lab challenge is a leap forward in a game I already loved. It is a major change to how you cure diseases. Now, rather than collecting a set of cards and discarding for a cure, you will collect samples, sequence and characterize the disease structure, testing your cure before finally having it cured. This is a lot of extra actions, and it takes some getting used to, but I found it to be leaps and bounds ahead of the base game for theme. You do feel like you're really working at the lab work to find these cures.\nWhen you perform a treat disease action, you may collect a sample for your cure. That is, you may transfer a cube to the lab for use rather than back to the supply. A disease sequence will be found and anyone in a lab may play a city card to characterize the sequence as a specific color. Later, as the sequence is worked on, a player in a lab may play an additional card of that color to test the cure, removing one cube from the board in the process. Lastly, a player in a lab may play the remaining cards needed for a cure, with the same results as in the base game. This is a long way to say that you will still be using 5 cards to cure, but it can be spread out among the players with greater ease. The trade-off is the lab work will consume a lot of actions. You'll find players won't have to rush off to particular cities as much to trade cards, but they will congregate around research stations as they work on cures. This is a variant that makes stations a bigger priority, but it isn't like people just ignored them in the base game.\nOverall, this is a great expansion. Like OTB, there are things I may not use every time, but nothing is a waste and there are parts I personally wouldn't want to play without. The theme and challenge of the lab work is what sells me.", "699" ], [ "My 8 year old daughter and I loved RTTA: Bronze Age. I have a dozen plays recorded here, and I'm sure I've forgotten as many more. So when Iron Age arrived yesterday, we were both eager to play it.\nHer enthusiasm didn't last.\nThere's a lot more going on in Iron Age than there was in Bronze Age. Enter in the ability to spread your empire through ports or provinces. Throw in armies, tributes, and conquests and there's a lot going on. It's by no means a complicated game for me, but if your kids liked Bronze Age, some may end up being like my daughter and finding the new additions too much. Hopefully, she will come around on that.\nSo, I ended up running through the solo challenge a few times after reading through the 4 pages of rules.\nYou begin your game by deciding whether you want to start with an extra port or an extra province. Provinces give you extra armies and tribute, but you have to feed your provinces. Ports don't give you any bonuses (Edit: they can give you extra goods per turn), but they don't require food either. Whichever you have the majority of determines the number of dice you get to roll. So if you have 4 provinces and 3 ports, you get to roll 4 dice, not 7. It gives you an interesting decision on whether to go all out in one area to gain dice or balance yourself. However, due to the quick nature of the game, there may be little incentive in balancing.\nOnce you have the dice, you'll see a lot of the familiar icons. You can roll to get food, population, and goods. Goods are now generic, no longer do you collect individual types of goods. Money is replaced by innovation which really becomes money when purchasing developments.", "528" ], [ "You also get a new dice called the fate dice. This can give you bonuses to food die, the dreaded skull, subtractions to food die, or the ability to seek conquests or tributes.\nThe beautiful simplicity of the Bronze Age was that all you had to do was build cities, maintain your food, and then throw massive amounts of people at monuments or goods at developments. With Iron Age, you have all that, but now you must maintain an army as well. Keep a low army, and you may get attacked by barbarians. A few barbarian attacks can really make your disasters score jump. Other players may also attack you. Though you don't lose anything, opponents can gain tribute if their army is larger than yours.\nI think this added feature could make for some really interesting multiplayer games. Now those development hoarders can't run away with a victory if they are constantly giving up 3-5 VPs to other players.\nThe solo game, though, becomes quite a challenge. The goal is to score 100 its in 8 rounds. In 3 games, I have yet to get half that. Nothing is more damaging to a fledging civilization than to be attacked by barbarians on the first turn!\nOverall, I have some mixed emotions about this game. I believe it to be a general step up from the Bronze Age. There's more to do, more to think about, and there's always the element of luck. But, it does limit the ability for some kids to get into it. For that, I rate it the same I rated Bronze Age, a 9. It'll be a great filler games in groups and provides a hefty solo challenge.", "528" ], [ "I have a love/hate relationship with Descent 2nd Edition. I love the looks and can't resist buying everything, but hate the gameplay and general experience. Let me explain... no, there is too much. Let me sum up:\nWhen it first came out, I was both excited and leery of the game. As with most FFG games, it looked great, and at a glance some of the mechanics felt like a good step up from 1st Ed. However, once I got the game and played it a few times with my friends, it fell short in a major way with a bunch of minor problems adding up to a not-so-fun game for us. The worst parts for us were less the mechanics and more the changes from a 'dungeon crawl' to an 'adventure' game. When it's more important for the heroes to run and grab wheat than kill the bloody goblins, it's not so fun for us.\nLow and behold, FFG announcted Game Night Kits for Descent. These kits promised a change in mechanics, from a 1vMany style game play, to a pure co-op. But even better, these kits promised some things that we found missing from the game, such as \"leveling up\" during a quest, finding treasure during a quest, a mechanical reason for killing monsters, and what appeared to be a fun game playable in one night.\nSo, needless to say, I had high expectations for this kit. I got my grubby little hands on the kit this week...\nDescent Game Night Kit: Forgotten Souls\nThe kit was relatively light. Packed in a non-discrete cardboard shipping box, it contained a Getting Started booklet, a Rule booklet, 10 Monster Activation Cards, 12 Exploration Cards, 10 Peril Cards, and 3 POD sized sheets for tracking doom and monster kills. It also contained acrylic health tokens and blue dice.\nThe acrylic pieces are kind of cool, but the transparent dice are not very different from the normal dice. Maybe if I had a whole set I'd notice it, but so far, meh. The rulebook wasn't very large, 16 pages with 5 of those being setups for specific encounters. The modified gameplay was light enough that if you know the core rules, it takes tops 10 minutes to explain how this co-op works.\nHow does it work?\nThe co-op is embodied in a quest. The one included in the kit is called Forgotten Souls.", "386" ], [ "The heroes stumble on a village where everyone is dead and a small boy leads them to a cave. Boy disappears, door slams shut, and the heroes now have to go through this dungeon to the end to find a way out. The villagers are in here, but now zombies. There are also barghests, flesh mulders, and dragons, and a big bad dragon deep at the end.\nEnough flavor text, how does it actually work? The game is played very similar to the core game. There's a board with the heroes and monsters on it, the heroes play exactly as the do in the base game, the \"Overlord\" has a turn as well but it's been automated. The heroes win by going through the encounters and accomplishing a specific goal. The heroes lose if the Doom token ever reaches the same space as the Fate token (they are on the same track, Doom goes up, Fate goes down).\nHow the game differs from the core game in the following ways:\n- Encounters\n- Overlord's Turn\n- XP & Loot\nEncounters\nEncounters are the main way of playing this game. There is an Encounter deck, and as the heroes explore the dungeon, they draw encounter cards that describe the map and monsters. There are three 'stages' to the game, and this is represented by special encounter cards. The first stage encounter is shuffled with the first 3 cards, the second stage is shuffled with the next 3 cards, and the final stage is shuffled with the last 2 cards. At the end of each stage, Heroes are rewarded XP and can immediately spend on skills (more on that later).\nAn Encounter indicates how the map is built, what monsters start on the map, and the specific goals for that part of the map. An Encounter is a card and a map description. Each encounter has an Entrance and an Exit, the Entrance hooks to the previous Encounter's Exit. The Exit has a door. The door cannot be opened until the Encounter card has been discarded (the objective of that particular encounter fulfilled or failed). Succeeding quests usually just refreshes the Fate track (one part of the 'timer' in the game). Failing a quest usually involves increasing the Doom track (the other part of the timer). Once the encounter is done, heroes can open the door exploring the next encounter.", "884" ], [ "Playing with 4, a chronicle so far that has spanned 5 games.\nPlaying so far exclusively on TTS; 3 of us purchased kickstarter and are awaiting our copies (North America)\nLearning the game\nNot nearly as bad as you might think if you hang out in these forums. We started with the playthrough, which is really just the first four turns or so, and then continued on into the gameplay. First game will require rules clarifications, googling these forums (what game doesn't, though?). Only in one case did we have one big confusion in the first game. This led to my post https://boardgamegeek.com/thread/2557132/definition-more-it-..., which ended up in the official errata https://docs.google.com/document/d/1p2tHzbTmQhU8tPfZeK5gSJvm...(I feel cool).\nPlaying the game\nThe best thing about this game is the constant shift in victory conditions, which can see huge swings in what you think to be true. For example, in our last game, we were certain the Chancellor would win. He had an impenetrable fortress of secrets, banners, and a relic that required we first remove it before going after any of his other key items. His citizen, who had been loyal all game, asked for reinforcements. Only then did the citizen make a mind blowing back stab play to campaign against his weakened chancellor and steal these treasures. This then made us certain the traitor citizen would win as the game was nearing the final rounds. This opened the door for me to then go in and campaign against the chancellor's remaining banner which provided me the oathkeeper title, and now it seemed certain I would win.", "366" ], [ "In a matter of a few key and highly strategic plays, the ebb and flow of power was palpable. Guess who ended up winning? None of the three of us! The other exile! Who found the one vision he needed for the win, with the vengeance-filled chancellor backing his win.\nWill you like this game?\nDo you like great stories like Game of Thrones? Do you like emergent narrative? Do you like highly strategic card interplay where spotting a combo at just the right time could catapult you from the back of the game to the front? Where the bullseye on someone's back is always changing? Where the rug gets pulled out from under everyone in succession, and everyone gasps? Then you will love it.\nMy one critique, which really isn't a critique, when I think about it\nKingmaking. There is a lot of kingmaking in this game, so be ready for that. Normally, it would feel a bit deflating to be in the lead, only for another player to hand the victory to a third player out of spite. They couldn't win themselves, but you had taken the win from them, so they pass the win to another. This can happen. However, when you step back and look at it from the story, and thematic point of view - it makes perfect sense. Why would the chancellor not want to pull the win away from the citizen who stabbed him in the back? Et tu <PERSON>?\nClosing thoughts for now\nThis game appealed to me early on, I followed the designer diary. It has quickly risen to a top 3 for me after 5 plays. I believe it has so much more to see, as our chronicle continues. Every single game has felt different from the last. If you are looking at the rulebook or reading the forums about the rulebook and thinking, ugh - I don't want to learn this...I would say, get on TTS, get a few friends, and just try it.", "366" ], [ "1989: Dawn of Freedom\nA game for 2 players designed by <PERSON> (and <PERSON>)\n\"What we may be witnessing is not just the end of the Cold War, or the passing of a particular period of post-war history, but the end of history as such: that is, the end point of mankind's ideological evolution and the universalization of Western liberal democracy as the final form of human government.\"\n<PERSON>, The End of History\nIntroduction\nHello and welcome to the latest edition of Roger's Reviews. I've been playing board games since I was a wee lad and wargames for over thirty years.\n1989: Dawn of Freedom follows in the footsteps, both literally and figuratively of the best selling game from GMT, Twilight Struggle. 1989 covers the events of that tumultuous year as the people of Eastern Europe and the Balkans shook off the shackles of their Communist regimes, with the most visually compelling one being the fall of the Berlin wall, symbol of the Iron Curtain since its erection in 1961.\n<PERSON> berlin 1989\nPlay\nI was a play tester for this game (I'm even listed in the credits at the back of the rule book) through the wargameroom.com league and have watched the evolution of this game from an early inception to this gorgeous new GMT release. I have also previously reviewed a print and play edition of this game (cf. ).\nPhotos in this review are used with the kind permission from <PERSON> (psicoserra).\nComponents\nGMT has outdone itself with this game, with one of the nicest game boards I've had the pleasure of playing on.\nThe colour contrasts for the different countries are clear and clean, the scoring track harkens back to the original Twilight Struggle with the +/- values on the track, the graphics are easy to see and read, and all the symbols are listed in the legend on the board. There are even spaces on the board for some of the key events, and the event tokens themselves are in full colour with artwork to easily distinguish them from one another.\nThere are two decks of cards in the game: the 110 card event deck split into the early, mid, and late war, and the 52 card power struggle deck for resolving scoring phases in the game. Counters are thick die cut counters with a nice heft and feel, with very clear easy to read large numbers. I might have to get a second set to use with my Twilight Struggle game. Yes, they're that nice.\nSomeone went to a lot of effort with the graphic design on this game, and it really shows. The event deck cards are easily sorted by early, mid, and late year by the colour stripe across the top, and the stars tell you whether it's a Communist, Democrat, or rare neutral event.", "92" ], [ "However, in the power struggle cards, while they are suited, in one of those \"that seems obvious in hindsight\" moments, I feel it would have been really helpful to put the elite, church, and worker symbols on the leader cards. Once you've played the game a few times it's easy to remember that you need to control the church space to use the church leader card, but with everything else so nicely designed with icons, it seems an unfortunate omission.\nDid I mention the gorgeous board? Stunning. Really.\nRules & Game Play\nAlthough there are some differences in the final rules, I will refer readers to my old review for the core mechanics and focus on the game play in the GMT edition. As a veteran Twilight Struggle player, I will also comment on some of the core differences between the two games; comparisons between the two are inevitable.\n1989 follows the basic premise of the Twilight Struggle game engine. We have a shared deck split between the early, mid, and late year. You can use cards either for operations or events, opponent events in your hand will trigger when you play them, and events with an asterisk on them are removed from the game.\nRelative to Twilight Struggle, events in this game are rather more dramatic in effect. For one example, The Legacy of 1968 allows the democrat player to put 1 support point into each and every space in Czechoslovakia that is not communist controlled. There are also more linked events in this game, such as the Sajudis + The Baltic Way + Breakaway Baltic Republics chain that has to be played in order.\nAdding to the interesting tension in the game, of the 110 event cards, 90 of them (82%) are starred events, meaning they leave the game when played. In Twilight Struggle that ratio is much closer to half. There are 44 communist events, 14 neutral events usable by either, and 42 democrat events. You spend your events at your peril, but it's even more harrowing to play a 2 ops card that lets your opponent remove 4 of your support points from the board!\nThe direct consequence of this is that hand management is incredibly fraught with peril.", "597" ], [ "This is a short review of my experience playing so far: 8 hours\nI hadn't read the rules or consumed too much information about the game since backing it, so my expectations were wide open. I learned how to play from <PERSON> Setup & Rules video, and filled in the gaps with the rulebook.\nI started playing the first recommended curse, The Voracious Goddess. So far I have played 8 hours over 3 sessions solo with one character. I am thoroughly enjoying this game. The mechanisms are incredibly smooth, and the 3 decks of cards interact so well with each other.\nMy character just died for the second time, and I'm really eager to give it another shot. The first time I just tried to do and see everything, and quickly ran out of action cards. The second time I started heading in the wrong direction, and realised too late, then walked around enjoying exploring.\nInitially I was worried that the game would be too easy without offering enough choices.", "211" ], [ "This is not the case! It is fantastic that some things you encounter help you and some hurt you.\nAnother thing I love is the movement mechanism. It is so clever that some terrains are harder to move from than others. Its also great that you can easily go to a linked terrain that you have visited before, but this is mitigated too with obstacles. Such great design!\nThe components are great! I love the size of the cards, which are small enough to fit heaps on a table and large enough to see the artwork. My first impressions of the dice and minis/standees was that they were quite small, but once I put them on the cards I felt they were the perfect size.\nFinally, the game feels just like a choose your own adventure book. But not a simple Goosebumps book, more like those roll and write adventure books that I loved growing up (Fighting Fantasy, Fabled Lands/Quest) that give you heaps of choices. This game uses cards instead of dice and character sheets though, which works well. It has the added bonus of a visible map and playing space with great artwork, AND the narrative is still present - most of the terrain cards have flavour text on the back.\nAll in all I am really impressed with this game, it has so many moving parts, it really is incredible that anyone designed it to operate so smoothly.\nSee you on the continent.", "336" ], [ "Sun of York\nA game for 2 players designed by <PERSON>, and published by GMT Games\n“Now is the winter of our discontent\nMade glorious summer by this son of <PERSON>;\nAnd all the clouds that low'r'd upon our house\nIn the deep bosom of the ocean buried.”\n― Richard The Third Act 1, scene 1, 1–4\nIntroduction\nThere was a time where collectible card games were a hot new thing. Magic the Gathering is still the complete king, nay, emperor, of that domain, but it also spawned not a few card games the include either a deck building or deck construction mechanic.\nI played a few of them. I tried and actually liked from Columbia, but as the ACW isn't a subject of great interest to me, it kind of came and went.\nI've always liked the idea of a card based wargame without a map having the forces and terrain deployed on a table top, and then resolving the action through the play of cards. There are lots of games in this general category. There's two series by Columbia, the aforementioned Dixie and their . can arguably be included. despite not being a card game has a similar idea of an abstracted terrain.\nSo how does the idea of an abstracted card version of the War of the Roses translate into game play? Let's find out.\nComponents, Rules, and Gameplay\nThe game comes with two deck of cards, one for the Lancastrians and one for the Yorkists.\nIt also comes with some dice, counters for marking specific kinds of information, the rules, and a pair of player aid cards.\nThe cards are nicely done and the information on them is nice and clear and easy to read.\nThe game includes 20 (!!) scenarios and a set of campaign rules for those who want to keep track of their progress (or lack thereof). There is also a nice simple rule for playing random scenarios.\nThe players set themselves up with a virtual field of play that has a left and right flank, and in the centre are three rows battle zones split into left, centre, and right.\nThis lovely custom playing mat from <PERSON> showcases it nicely:\nEach turn is split into four phases: morale checks, combat, movement, and a discard phase. To win the game, you need to capture the centre rear space of your opponent, or both the left and right rear positions.\nThe initial deployment has each player take out the leader and terrain cards specified from the scenario and into the spaces they're assigned to, and then draws 16 more cards from their remaining deck to be deployed as they see fit.", "92" ], [ "You then flip it all face up and have at it.\nThe rules are relatively straightforward and everything you need to know about moving, engaging, fighting, and flanking are all easily found and explained in the rulebook.\nConclusions\nSun of York was a game I really wanted to like, but ultimately it left me unsatisfied. The fault likes not with the game itself, but rather my likes and desires in a game. As I stated in the introduction, I like the idea of an abstracted card game of a battle, but the reality is that I really want to have a map with units and terrain.\nThe deck contains a random mix of units, terrain, and leaders. There are some special event cards that you can play as well. This means that no two scenarios will be alike, yes, but also means that you can get completely ahistorical results.\nI may be overly picky on this point. I'm no scholar of the War of the Roses, and I'm not going to be able to point expertly at how the way combat is resolved in this game is a poor simulation of how archers behaved in this era. However, I don't get a strong sense of time and place with this game, and I could just as easily be playing a generic card game with soldiers and archers and leaders.\nIt's clear then that my preference for having a map and units to help me conceptualize what's going on in front of me. And that's no indictment of Sun of York, it just doesn't make it a game for me.\nIf you like card games like this, and you like this era, it's a solid entry in the genre.\nThank you for reading this latest installment of Roger's Reviews. I've been an avid board gamer all my life and a wargamer for over thirty years. I have a strong preference for well designed games that allow players to focus on trying to make good decisions.\nAmong my favorites I include , the , the , , , , , and\nYou can subscribe to my reviews at this geeklist: and I also encourage you to purchase this very stylish microbadge:", "993" ], [ "I got my first two plays of Lords of Waterdeep in a session the other night, and haven't had much chance to discuss it. Looking around, I see at least half a dozen threads where LoW is being hotly debated, and rather than get involved in all those discussions, and inevitably end up repeating myself, I've decided to write a short review so I can gather my early thoughts on the game in one place. Others with more experience have already reviewed the game, so if you want in depth analysis, rules summaries or lots of pretty pictures, I advise you to read one of those. All you'll find here are my own early impressions.\nOverview\nThe system is very clean and easy to absorb. We came up to speed very quickly, even though one of the players knew absolutely nothing about the game before we sat down to play, and I was the only one who had read all the rules. We all had a solid grasp of what we were trying to accomplish before we were half way through our first game. We wasted relatively little time looking up rules, and only had a couple of questions we wanted to look up after playing.\nI'm confident that the game will scale well. The game is designed for 2-5 players, and my experience is that 3 is often a troublesome number. That was not the case here; it worked fine with 3. The number of turns in a game is determined by the number of Agents each player receives, and that varies with how many are playing, so playing time shouldn't vary much as you add or remove players. You have opportunities to do good or harm to others, but this isn't a system that encourages long term alliances. There is a map, and players will acquire buildings to place on it, but there is no geographical adjacency factor; everybody will contend with everyone else.\nTheme\nThe box has Dungeons & Dragons prominently displayed on the cover. Players are leading named factions, have named Lords, send Agents on quests, purchase buildings which provide various advantages, play intrigue cards, etc. The Quests and Intrigue cards have flavor text, taken I presume from the D&D universe. You also hire Adventurers - wooden cubes of various colors which are supposed to represent wizards, fighters, rogues and clerics.\nAll of that sounds very thematic, but you could change the Lords to Famous Chefs, the Adventurers to Recipe Ingredients and the Quests to Menu Items, and you'd have a game about running the most successful restaurant.", "386" ], [ "You wouldn't have to change any play mechanics. If being drawn into a narrative is crucial for you, LoW is not going to ring that bell.\nWhile the theme is plastered on rather than tightly bound to player actions, that plaster is well and consistently applied. If you know who <PERSON> is, and are familiar with the Red Sashes, seeing them in the game will probably please you. I'm not a D&D player, and don't know them, but the types are familiar and I wouldn't have been as likely to play a restaurant game in the first place. Once in, I found a game that is weak in terms of narrative, but well worth playing.\nDiscWorld: Ankh-Waterdeep\nLoW reminds me somewhat of D:A-M. I found D:A-M's card text and illustrations so interesting that I followed up and have now read a couple of Discworld books. I think it's entirely possible that some Eurogamers might follow a similar course, checking out D&D related titles after playing LoW. In both games, a great deal of effort was put into art and flavor text, and that can be interesting, but neither game tells much of a story despite the thematic underpinnings. The theme isn't bound to the mechanics.\nOne interesting parallel is that in both LoW and D:A-M, the players draw a card during setup representing a powerful figure in the city portrayed, and the identity of that figure establishes the long term strategy for the player. In D:A-M there are 3 lords who have identical victory conditions, and 4 others with unique conditions. This keeps the players guessing about the motives of their opponents nicely.\nIn LoW, there are 5 different quest types, and 10 of the 11 lords receive bonus points at game's end for having completed quests for 2 of those 5 types. There is also one 1 lord (lady) with a different agenda; she provides an end game bonus for buildings held rather than quests completed. There is less mystery in the LoW assignments, but it works well, and serves the purpose of obscuring scores until the final reckoning.\nComponents\nThere are several threads in the LoW forums with ominous sounding names, possibly giving the impression that various components (cards, wooden bits, box, insert) are defective or poorly designed. I attribute this to jaded gamer syndrome. The game I received is top quality.", "755" ] ]

[ 6005, 5436, 10918, 1314, 6611, 7437, 9499, 2230, 564, 9629, 5006, 9989, 8145, 4957, 2131, 3582, 11229, 2463, 9398, 7422, 8755, 3584, 6154, 9174, 3209, 1934, 8016, 3300, 528, 5763, 9204, 8202, 537, 6270, 3289, 2859, 7271, 11171, 6355, 11419, 10113, 11378, 6582, 2857, 9988, 8333, 7601, 7307, 3931, 11335, 8952, 3534, 1752, 2613, 2560, 11161, 8474, 9369, 3954, 7714, 4015, 5845, 4480, 4136, 8197, 8336, 8093, 3001, 6284, 6815 ]

[ [ "How to obtain a convergent solution iteratively for a linear system of equations?\nI am working on a problem that requires an iterative procedure to solve a linear system of equations, the system of equations in matrix form is:\n$$\\underbrace{\\begin{bmatrix} r_{11} & r_{12} & r_{13} & \\cdots & r_{1j} \\ r_{21} & r_{22} & r_{23} & \\cdots & r_{2j} \\ r_{31} & r_{32} & r_{33} & \\cdots & r_{3j} \\ \\vdots & \\vdots & \\vdots & \\ddots & \\vdots \\ r_{i1} & r_{i2} & r_{i3} & \\cdots & r_{ij} \\end{bmatrix}}\\textit{R} \\underbrace{\\begin{bmatrix} a{1} & 0 & 0 & \\cdots & 0 \\ 0 & a_{2} & 0 & \\cdots & 0 \\ 0 & 0 & a_{3} & \\cdots & 0 \\ \\vdots & \\vdots & \\vdots & \\ddots & \\vdots \\ 0 & 0 & 0 & \\cdots & a_{j} \\end{bmatrix}}\\textit{A} + \\underbrace{\\begin{bmatrix} b{1} & b_{2} & b_{3} & \\cdots & b_{j} \\ b_{1} & b_{2} & b_{3} & \\cdots & b_{j} \\ b_{1} & b_{2} & b_{3} & \\cdots & b_{j} \\ \\vdots & \\vdots & \\vdots & \\ddots & \\vdots \\ b_{1} & b_{2} & b_{3} & \\cdots & b_{j} \\end{bmatrix}}\\textit{B} = \\underbrace{\\begin{bmatrix} c{1} & c_{1} & c_{1} & \\cdots & c_{1} \\ c_{2} & c_{2} & c_{2} & \\cdots & c_{2} \\ c_{3} & c_{3} & c_{3} & \\cdots & c_{3} \\ \\vdots & \\vdots & \\vdots & \\ddots & \\vdots \\ c_{i} & c_{i} & c_{i} & \\cdots & c_{i} \\end{bmatrix}}\\textit{C}\\ R{i, j}A_{j, j} + B_{i, j} = C_{i, j} $$ Now matrix R is fully known (input), matrices A, B, C are unknown. I am working on an iterative procedure in which I provide initial guesses for A and B, then calculate C.", "490" ], [ "The iteration is to be carried out till I get a converged value for C (output I require). The code is being developed in Python. So far no luck in choosing the initial guess too.", "416" ], [ "Comparing algorithms for tridiagonal linear systems solution\nBelow there are two algorithms for solving tridiagonal linear systems of the form $$ \\left[ \\begin{array}{ccccc|c} b_1 & c_1 & & & &d_1\\ a_2 & b_2 & c_2 & & & d_2\\ & \\ddots & \\ddots & \\ddots & & \\vdots\\ & & a_{n-1} & b_{n-1} & c_{n-1} & d_{n-1}\\ & & & a_n & b_n & d_n \\end{array} \\right]. $$ I called them Algorithms A and B.", "490" ], [ "Both of them are equivalent to Gaussian elimination, but with important difference in the form of the resulting triangular (bidiagonal) matrix.\nMy main question is: which one of them is more preferrable?\nAlgorithm A is the one that described in Wikipedia and many textbooks, it is called <PERSON> algorithm and is implemented, for example, in Numerical Recipes in some tricky form. Algorithm B is more straightforward and, in my opinion, is more numerically stable in cases when $|b_i|\\gg|a_i|+|c_i|$ . Though I haven't seen Algorithm B in texbooks, note that exactly this algorithm is implemented in the mentioned Wikipedia article, see \"Implementation in Fortran 90\", while \"Implementation in Matlab\" deals with Algorithm A (\"Implementation in C\" in its current state is a mess that does not seem to work at all).", "768" ], [ "ODE45 function in Matlab diverges from obvious solution, is it normal?\nI wish to simulate the behaviour of a double-pendulum-like system. The system is a 2-degrees-of-freedom robot manipulator that is not actuated and will, therefore, behave mostly like a double-pendulum affected by gravity.", "935" ], [ "The only main difference with a double-pendulum is that it is composed of two rigid bodies with mass and inertia properties at their centers of mass.\nBasically, I programmed ode45 under Matlab to solve a system of ODEs of the following type:\n$$ \\left[ \\begin{array}{cccc} 1 & 0 & 0 & 0\\ 0 & M_{11} & 0 & M_{12}\\ 0 & 0 & 1 & 0\\ 0 & M_{12} & 0 & M_{22} \\end{array} \\right] \\left[ \\begin{array}{c} \\dot{x}_1\\ \\dot{x}_2\\ \\dot{x}_3\\ \\dot{x}_4 \\end{array} \\right]= \\left[ \\begin{array}{c} x_2\\ -V_1-G_1\\ x_4\\ -V_2-G_2 \\end{array} \\right] $$\nwhere $x_1$ is the angle of the first body with respect to the horizontal, $x_2$ is the angular velocity of the first body; $x_3$ is the angle of the second body with respect to the first body, and $x_4$ is the angular velocity of the second body. All of the coefficients are specified in the following code, in the rhs and fMass functions I created.\nclear all\nopts= odeset('Mass',@fMass,'MStateDependence','strong','MassSingular','no','OutputFcn',@odeplot);\nsol = ode45(@(t,x) rhs(t,x),[0 5],[pi/2 0 0 0],opts);\nfunction F=rhs(t,x)\nm=[1 1];\nl=0.5;\na=[0.25 0.25];\ng=9.81;\nc1=cos(x(1));\ns2=sin(x(3));\nc12=cos(x(1)+x(3));\nn1=m(2)*a(2)*l;\nV1=-n1*s2*x(4)^2-2*n1*s2*x(2)*x(4);\nV2=n1*s2*x(2)^2;\nG1=m(1)*a(1)*g*c1+m(2)*g*(l*c1+a(2)*c12);\nG2=m(2)*g*a(2)*c12;\nF(1)=x(2);\nF(2)=-V1-G1;\nF(3)=x(4);\nF(4)=-V2-G2;\nF=F';\nend\nfunction M=fMass(t,x)\nm=[1 1];\nl=0.5;\nIzz=[0.11 0.11];\na=[0.25 0.25];\nc2=cos(x(3));\nn1=m(2)*a(2)*l;\nM11=m(1)*a(1)^2+Izz(1)+m(2)*(a(2)^2+l^2)+2*n1*c2+Izz(2);\nM12=m(2)*a(2)^2+n1*c2+Izz(2);\nM22=m(2)*a(2)^2+Izz(2);\nM=[1 0 0 0;0 M11 0 M12;0 0 1 0;0 M12 0 M22];\nend\nNotice how I set the initial condition of $x_1$ (angle of the first body with respect to the horizontal) so that the system starts in a completely vertical position. This way, since only gravity is acting, the obvious outcome is that the system should not move at all from that position.\nNOTE: in all of the graphics below, I plotted the solutions $x_1$ and $x_3$ with respect to time.", "804" ], [ "Inverse problems in Computational Chemistry: The case of Inverse eigenvalue Problems for molecule structures\nMathematics Background\nAn inverse eigenvalue problem (IEP) is the problem of reconstructing a matrix with a special structure from prescribed spectral data. By structure we mean the pattern of entries that are either zero or nonzero. There are many different types of IEPs with different level of difficulty which depends on the structure of the matrices which are to be reconstructed and the available eigen information. For example consider the following real Jacobi matrix:\n$$ A_n = \\begin{bmatrix} a_1&b_1&0&0&0&0& \\cdots & 0\\ b_1&a_2&b_2&0&0&0&\\cdots&0\\ 0&b_2&a_3&b_3&0&0&\\cdots&0\\ 0&0&b_3&a_4&b_4&0&\\cdots&0\\ 0&0&0&b_4&a_5&b_5&\\cdots&0\\ 0&0&0&0&\\ddots&\\ddots&\\ddots&0\\ 0&0&0&0&\\cdots&b_{n-2}&a_{n-1}&b_{n-1}\\ 0&0&0&0&\\cdots&0&b_{n-1}&a_n \\end{bmatrix} $$\nSuch that $b_i$s are nonzero and $a_i$s may or may not be zero. An IEP about this matrix is this:\nLet $A_i$ be $i$th leading principle submatrix of $A_n$ and let $n$ be an even number, for a given Jacobi matrix $J$ of size $n/2 \\times n/2$ and list of numbers $\\Lambda = {\\lambda_1, \\cdots, \\lambda_n}$, find an $n \\times n$ Jacobi matrix $A_n$ such that $J$ is its minor principle submatrix and $\\Lambda$ is its eigenvalues.\nor\nFor a given list of real numbers $\\Lambda = {\\lambda_1, \\cdots, \\lambda_n }$ and $\\mu ={ \\mu_1, \\cdots, \\mu_{n-1} }$, find a Jacobi matrix $A_n$ such that $\\Lambda$ is its eigenvalues and $\\mu$ is eigenvalues of $A_{n-1}$.\nMany different problems are considered by researchers in many papers.\nBecause graphs are appropriate tools for presenting a matrix structure, many papers concern IEP of graphs.", "945" ], [ "For a given symmetric matrix $A_{n \\times n}$, graph of $A$ is a graph $G=(V,E)$ such that $V = {v_1, \\cdots,v_n}$ and edge ${v_i,v_j} \\in E$ if entry $[A]_{ij} \\neq 0$. In many papers IEP of matrix of graphs (path and broom graph (path graph is actually a symmetric Jacobi matrix), star graph, four different IEPs for paw graph and etc.) are investigated by researchers. Please note that it is also possible to consider IEP of a directed graph, in this case its matrix will not be symmetric anymore.\nWhat I am looking for ...\nAfter a few years of studying IEPs in pure mathematics, I am looking for inverse eigenvalue problems with real practical application. many times, problems are modeled as a matrix and the limits on the problem are moved to the matrix entries or its spectral information and then researchers study the matrix. For example IEP of mass spring system is investigated which is a topic in physics.\nIEP of problems in Computational Chemistry are rarely (or even never) investigated and because many entities and molecules in chemistry are look like some graphs (path or cycle), and graphs can also be modeled as a matrix, hence different types of IEPs may happen there. I ask for any help to introduce some field of studies or references or even cooperation to help me in doing this.\nThanks in advance.", "180" ], [ "How to Solve Optimisation Problems using Penalty Functions in Python\nI am working on a implementing a simple quadratic optimisation problem:\n$$\\min _x \\; {\\underline{x}}^T Q {\\underline{x}}$$ $$s.t. \\,\\quad {\\underline{\\mu}}^T{\\underline{x}} = R^*$$ $$ \\quad \\quad \\underline{1}^T\\underline{x} = 1 $$ I also expect to go on to include the inequality constraint, as an additional complexity, once the above is working.\n$$ x_i \\geq 0$$ The method I think is simplest, and which I understand best for implementing these constraints, is the penalty function method, where we modify the objective function to 'steer' the optimisation away from forbidden regions.", "490" ], [ "By carefully parameterising the size of the penalties, I have achieved good results using SciPy's built-in Nelder-Mead Simplex algorithm, using the objective function below.\ndef objective(x):\nQ = DF.cov() # Covariance matrix\n# Penalty Function method\npenalty1 = 0.0005 * abs(np.sum(x)-1) # Large for sum(x) <> 1\npenalty2 = 0.05 * abs(R_min - np.matmul(Mus.transpose(), x)) # Large for returns <> R_min\nreturn np.matmul(x.transpose(),np.matmul(Q,x)) + penalty1 + penalty2\nNow, I wish to use other optimisation algorithms (in particular BFGS and Newton-CG), which require the gradient and Hessian of the objective function. I have implemented the derivative functions in the unconstrained case, but by adding the penalty terms to the objective (and the derivatives of the penalties to the gradient function) optimisation fails with the following error:\nWarning: Desired error not necessarily achieved due to precision loss.\nCurrent function value: 0.000056\nIterations: 0\nFunction evaluations: 780\nGradient evaluations: 96\n(Previously Iterations would be a few hundred). This strictly occurs with penalty1, but not penalty2 by itself, so either my derivative is wrong for penalty1:\npenalty1_der = np.sign(x)\nOr can I not use the L1 norm in this way? I also tried replacing the constraint with a smoother, quadratic approximation:\npenalty1 = np.matmul((x - vector_ones).transpose(), (x - vector_ones))\nbut unfortunately, although this prevents the error, Minimize() seems to completely ignore my penalty functions (even with vastly increased parameters).\nHow can I implement my constraints such that I can solve the problem using BFGS/Newton-CG?", "509" ], [ "Open Source Quadratic Programming with Piecewise Linear Objective\nI am looking for an open source solver to solve the a quadratic programming problem with an additional piecewise linear objective, as show below. The problem is fairly small ($\\mathbf{x}$ is a vector of dimension 120).\n\\begin{equation} \\max_{x}: \\mathbf{x}^{T} \\mathbf{q_0} - \\mathbf{x^{T}} P_0 \\mathbf{x} - f(\\mathbf{x}) \\end{equation}\nNote that above $P_0$ is positive semidefinite and $f$ is piecewise linear for each variable in $\\mathbf{x}$ but not convex.", "935" ], [ "For each $x_i$, $i \\in \\left{1, ..., 120\\right}$, $f(x)$ would be a vector of coordinate points, e.g.\n[(x_0, y_0), (x_1, y_1), ..., (x_N, y_N)]\nFor any given $x_i$, $f(x_i)$ looks something like the following.\nSince $f$ does not depend on any cross terms in $\\mathbf{x}$, the above optimization could also be written as\n\\begin{equation} \\max_{x}: \\mathbf{x}^{T} \\mathbf{q_0} - \\mathbf{x^{T}} P_0 \\mathbf{x} - (f(x_1) + ... + f(x_{120})) \\end{equation}\nThe are also linear constraints of the form $A\\mathbf{x} < \\mathbf{b}$ are added.\nI have formulated the problem in Gurobi which is fairly straightforward but was hoping to compare this to an open source solver. Looking around it seems like GLPK would work for this, but I have no experience using this library so was hoping for a bit of info related to this or alternative solutions.\nA sample problem for gurobi using the matlab API is shown below.\nN = 2;\nq_0 = [-3.31e3, -5.07e3];\nP_0 = [-0.90e-04 -0.63e-04;\n-0.63e-04 -0.90e-04];\nx = [-2.0000e9, -1.0000e9, -0.8000e9, -0.6000e9, -0.4000e9, -0.2500e9,...\n-0.1000e9, -0.0500e9, -0.0250e9, -0.0100e9, -0.0010e9, 0, 0.0010e9,...\n0.0100e9, 0.0250e9, 0.0500e9, 0.1000e9, 0.2500e9, 0.4000e9,...\n0.6000e9, 0.8000e9, 1.0000e9, 2.0000e9];\ny = [2.938964e6, 0.753364e6, 0.488104e6, 0.280144e6, 0.129472e6,...\n0.053766e6, 0.011007e6, 0.003751e6, 0.001435e6, 0.000465e6,...\n0.000037e6, 0, 0.000037e6, 0.000465e6, 0.001435e6, 0.003751e6,...\n0.011007e6, 0.053766e6, 0.129472e6, 0.280144e6, 0.488104e6,...\n0.753364e6, 2.938964e6];\nparams.outputflag = 0;\n%formulate model\nmodel.obj = zeros(N, 1);\nmodel.Q = sparse(P_0);\nmodel.A = sparse(zeros(1, N));\nmodel.sense = '=';\nmodel.rhs = 0;\nmodel.ub = repmat(1e9, N, 1);\nmodel.lb = repmat(-1e9, N, 1);\nmodel.modelsense = 'max';\n% piecewise tcosts\nfor i = 1:2\nmodel.pwlobj(i).var = i;\nmodel.pwlobj(i).x = x;\nmodel.pwlobj(i).", "935" ], [ "Matrix Balancing Algorithm\nI have been writing a control system toolbox from scratch and purely in Python3 (shameless plug : <PERSON> ). From my past research, I have always complaints about the Riccati solver care.m for reasons that are technical/irrelevant.\nHence, I've been writing my own set of routines. One thing I can't find a way around is to obtain a high-performance balancing algorithm, at least as good as balance.m. Before you mention it, xGEBAL family is exposed in Scipy and you can basically call from Scipy as follows, suppose you have a float type 2D array A:\nimport scipy as sp\ngebal = sp.linalg.get_lapack_funcs(('gebal'),(A,)) # this picks up DGEBAL\nAb, lo, hi, scaling , info = gebal(A, scale=1 , permute=1 , overwrite_a=0 )\nNow if I use the following test matrix\narray([[ 6. , 0. , 0. , 0. , 0.000002],\n[ 0. , 8. , 0. , 0. , 0. ],\n[ 2. , 2. , 6. , 0. , 0. ],\n[ 2. , 2. , 0. , 8. , 0. ],\n[ 0. , 0. , 0.000002, 0. , 2. ]])\nI get\narray([[ 8. , 0. , 0.", "768" ], [ ", 2. , 2. ],\n[ 0. , 2. , 0.000002, 0. , 0. ],\n[ 0. , 0. , 6. , 2. , 2. ],\n[ 0. , 0.000002, 0. , 6. , 0. ],\n[ 0. , 0. , 0. , 0. , 8. ]])\nHowever, if I pass this to balance.m, I get\n>> balance(A)\nans =\n8.0000 0 0 0.0625 2.0000\n0 2.0000 0.0001 0 0\n0 0 6.0000 0.0002 0.0078\n0 0.0003 0 6.0000 0\n0 0 0 0 8.0000\nIf you check the permutation patterns, they are the same however the scaling is off. gebal gives unity scalings whereas matlab gives the following powers of 2: [-5,0,8,0,2].\nSo apparently, these are not using the same machinery. I've tried various options such as Lemonnier, Van Dooren two sided scaling, original Parlett-Reinsch and also some other less-known methods in the literature such as the dense version of SPBALANCE.\nOne point maybe I might emphasize is that I am aware of <PERSON>'s work; in particular the Symplectic Balancing of Hamiltonian Matrices specifically for this purpose. However, note that this type of treatment is done within gcare.m (generalized <PERSON> solver) and balancing is done directly via balance.m. Hence, I would appreciate if someone can point me to the actual implementation.\nDisclosure: I am really not trying to reverse engineer mathworks code: I actually want to get away from it due to various reasons including the motivation of this question, that is to say, I don't know what it is doing which costed me lots of time back in the day. My intention is to get a satisfactory balancing algorithm that allows me to pass CAREX examples such that I can implement <PERSON><PHONE_NUMBER>\n0 0.0003 0 6.0000 0\n0 0 0 0 8.0000\nIf you check the permutation patterns, they are the same however the scaling is off. gebal gives unity scalings whereas matlab gives the following powers of 2: [-5,0,8,0,2].\nSo apparently, these are not using the same machinery. I've tried various options such as Lemonnier, Van Dooren two sided scaling, original Parlett-Reinsch and also some other less-known methods in the literature such as the dense version of SPBALANCE.\nOne point maybe I might emphasize is that I am aware of Benner's work; in particular the Symplectic Balancing of Hamiltonian Matrices specifically for this purpose. However, note that this type of treatment is done within gcare.m (generalized Riccati solver) and balancing is done directly via balance.m. Hence, I would appreciate if someone can point me to the actual implementation.", "768" ], [ "Construction of Prolongation and Restriction Operator for Geometric Multigrid (2D-FEM): Resulting in a Decreasing Solution\nConsider the following problem, $$ -\\Delta u(x) = f(x), \\qquad x \\in \\Omega \\ u(x) = 0,\\qquad x \\in \\partial \\Omega$$ with $\\Omega = [0,1]\\times [0,1]$ being the domain and $\\partial \\Omega$ being the boundary. The source term $f(x) \\in L^2(\\Omega)$ is a smooth source term. The exact solution is known.\nI have generated the two following triangulations of the domain, dimensioned $81\\times 81$ and $289 \\times 289$.\nUsing regular P1-FEM, I have constructed a linear system for each of these two meshes, $$ A_1 u_1 = f_1, \\qquad A_2 u_2 = f_2.$$\nThe direct solutions of the two systems are working as intended, with the finer mesh having a relative error (of $L^2$-norm) of $0.0077$ compared to the known exact solution and the coarser mesh being a bit less accurate.\nNow, rather than using a direct solver, I am attempting to construct a two-grid solution for this problem. I am using a V-cycle method, with the following structure:\n1. Start with the fine grid, and perform 3 iterations of the dampened Jacobi method (weight $\\omega = 2/3$), using zero as initial guess. The damped Jacobi method I have implemented has the following structure $$ u^{n+1} = u^n + \\omega D^{-1} (f - Au^n),$$ where $D$ is the diagonal of $A$. This seem to work as intended, as the $L^2$-norm of the relaxed solution is lower than the $L^2$-norm for the initial guess. We can denote this relaxed solution by $u_2$.\n2. Compute the residual of the relaxed solution by $r_2 = A_2 u_2 - f_2$.\n3. Restrict the residual $r_2$ to the coarse mesh. Here, I am using an injection restriction operator, where I simply remove the finer nodes and keep the nodes which are part of both meshes.", "935" ], [ "The general structure of this operator is $$ R = \\begin{bmatrix}1 & 0 & 0 & \\cdots & & & 0\\ 0 & 1 & 0 & \\cdots & & & 0\\ 0 & 0 & \\ddots & \\cdots & & & 0 \\ 0 & 0 & 0 & 1 & 0 & \\cdots & 0\\end{bmatrix}, \\qquad (81 \\times 289)$$ The implementation of this operator seem to work as I intend it to. The dimensions become correct, and the \"finer\" nodes are removed from the residual. We can denote the restricted residual $r_2$ as $Rr_2$.\n4. Solve the coarse system directly. Using Matlab notation and denoting the solution as $e$, $e = A_1 \\setminus (Rr_2)$. This results in a $L^2$ error which is larger than the relaxed solution $u_2$, which seems odd.\n5. Apply a prolongation operator to the solution $e$. The prolongation operator that I am using is a linear interpolation. The nodes which are shared between the coarse grid and the fine grid are left unchanged, while the finer nodes are computed as the average of the two closest coarse nodes (on the same edge). This results in the following structure of the prolongation operator, $$ I = \\begin{bmatrix} 1 & 0 & 0 & \\cdots & 0 \\ 0 & 1 & 0 & \\cdots & 0 \\ 0 & 0 & \\ddots & \\cdots & 0 \\ 0 & 0 & \\cdots & & 1 \\ 0.5 & 0.5 & 0 & \\cdots & 0 \\ 0 & 0 & 0.5 & 0.5 & 0\\ \\vdots & \\vdots & \\vdots & \\vdots & \\vdots \\ 0 & 0 & 0.5 & 0 & 0.5\\end{bmatrix}, \\qquad (289 \\times 81).$$ Again, the dimension of this prolongation operator seem correct, and the vectors seem to update as intended. We can denote $u_1 = Ie$ as the prolonged solution $e$ onto the finer grid.\n6. I update the original relaxed solution $u_2$ as $u_2 = u_2 - Ie$.\n7.", "490" ] ]

[ 1061, 434, 2518, 3938, 3286, 7351, 150, 11425, 8189, 8361, 2006, 11097, 485, 7487, 9858, 1480, 2166, 6417, 10667, 9436, 3559, 3612, 5640, 2429, 9201, 1223, 1244, 9081, 9851, 9616, 5502, 10135, 4070, 10905, 11114, 8916, 4928, 5631, 9881, 1669, 4906, 6348, 6625, 5729, 4627, 6081, 1446, 9303, 1563, 2239, 8863, 1741, 10457, 8721, 5759, 9205, 3435, 2823, 5479, 570, 3082, 64, 9783, 9784, 6940, 4192, 11022, 8613, 4280, 5988 ]

[ [ "There are a couple of ways to approach this, and I'll try to keep my notation consistent with <PERSON>. I think the most fundamental thing to recognize is that a complex $t_1$ is a choice (so it can't really have an effect), but, in the problem described, a complex $t_2$ is inevitable.\nPlaying with phases\nLet's say, before we apply the field, everything is time-reversal invariant and all of the hopping terms ${t_1,t_2}$ for nearest and next-nearest neighbor are (chosen to be) real. Now, this is not entirely necessary; you could for instance, change your basis by multiplying all of the B-site basis functions with a phase factor. Then the nearest-neighbor hopping $A\\rightarrow B$ picks up a phase, and hopping $B\\rightarrow A$ picks up the opposite phase. Voila, complex $t_1$. But this is just a game with the basis, so it clearly won't change the spectrum or have any physical consequences.\nWe could do something similar with next-nearest neighbor, but we would have to obnoxiously redefine our tight-binding basis function so that it varies in phase from one A-site to another A-site, and then the hopping element would not be uniform between all A-sites (or between all B-sites). It probably isn't clear a priori what restrictions math may place on us in this game, but we'll get to that. My point here is just that there's no obvious reason you can't put a (site-dependent) phase in $t_2$ before applying the field, at the cost of making the problem quite annoying. But again, it's just a basis-change, nothing physical.\nPhase around a closed loop\nNow let's apply a field, but keep in mind that we can still change bases (or gauges) to affect the phases of the hopping terms as discussed above.", "298" ], [ "As <PERSON> notes, the effect of the field is to multiply the hopping elements by a phase factor $\\exp\\left[ie/\\hbar\\int A\\cdot dr\\right]$. Let's try two experiments.\n* First, do some nearest-neighbor (NN) hopping around some closed path and look at the phase we accumulate. If you try this out, you'll notice that, if you're NN hopping on this lattice and you want to get back to where you started, you will always enclose some integer number of hexagonal unit cells (because you can't just \"cut through\" a cell with only NN). And every cell has zero net flux, so your phase factor for a closed NN path is $\\exp\\left[ie/\\hbar\\oint A\\cdot dr\\right]=\\exp\\left[ie/\\hbar\\sum_{cells} \\iint B dA\\right]=\\exp\\left[ie/\\hbar\\sum_{cells} 0\\right]=1$\n* Now, let's do some second nearest neighbor (2NN) hopping around a closed path. For instance, let's take a loop of three sites within the same hexagon. The path enclosed is some portion of the hexagon, which may have non-zero net flux so your path can accumulate some phase $\\exp\\left[ie/\\hbar\\oint A\\cdot dr\\right]=\\exp\\left[ie/\\hbar\\iint BdA\\right]=e^{i\\theta}$\nNote that changing bases or gauges does not alter either of the above values. The NN path will always collect no phase, and the same 2NN path will always collect the same $e^{i\\theta}$, because we've expressed these phases in terms of base- and gauge-invariant quantities (just the magnetic field $B$).\nConsequences\nSo, if we try to play with the complex hopping element between second nearest neighbors, we won't be able to get it back to being a real value everywhere, because we know that the 2NN hopping elements have to combine to form a phase $e^{i\\theta}$ around a certain loop. On the other hand, this restriction does not prevent us from making every NN hopping element just real $t_1$ because the accumulated phase is always 0. Big picture, the topology of the paths possible with NN and 2NN are different, and restrict the allowable phases in different ways.\nThe complex possibilities for $t_1$ don't actually have any effect on the spectrum, and we see this because we can just transform this phase away. But the complexity of $t_2$ is something we're stuck with, so Haldane explores its consequences.\nI hope that helps!", "768" ], [ "I'll go ahead and say that one can roughly classify systems into\n1. Systems with a unique ground state.\n2. Systems that have multiple (possibly infinitely many) degenerate ground states, but that will tend to select a unique one by some mechanism.\n3. Systems with topological ground state degeneracy.\n(I won't rule out there existing additional classes, and I'd welcome learning about them in the comments, but this classification seems satisfactory for the current answer.)\nClearly, class 1 is easy to deal with. There might be some system where it's difficult to numerically resolve the gap to the first excited state, but in practice, with finite size effects and all, the gap will usually be larger than machine resolution. An example of such a system would be spins coupled to a polarizing magnetic field.\nClass 2 represents includes some of our most well studied systems, such as the antiferromagnetic Ising model $H_I=\\sum_{\\langle i,j\\rangle} S_i^zS_j^z$ on the square lattice, or the <PERSON> model $H_H=\\sum_{\\langle i,j\\rangle} \\mathbf{S}_i \\cdot \\mathbf{S}_j$ on a cubic lattice. Clearly both models allow for a set of degenerate ground states. You're correct that for small systems, and in principle also larger ones, the system could be in a superposition of different several such states. However, in condensed matter we're usually interested in phases of matter, a concept which is only really well-defined in the thermodynamic limit - as the system size tends to infinity.\nIn that limit we tend to have spontaneous symmetry breaking - that is, for whatever reason (e.g. a small perturbation from the environment) the system picks out a ground state of lower symmetry than the Hamiltonian.", "976" ], [ "If this wasn't the case, a permanent magnet would be a superposition of a state with all spins along $+\\hat{z}$ and a state with all spins along $-\\hat{z}$, and averaging the magnetization would yield zero - clearly an unphysical result. In other words, the physically observable quantities in macroscopic systems tend to arise from a symmetry broken ground state, not a superposition of degenerate states. Finally, for completeness, I will also mention that in some systems there is also a phenomenon called order by disorder that helps reduce the ground state degeneracy by entropic mechanisms.\nFor a DMRG calculation (and some other methods), assuming you want to say something about large systems, you will often want to include a small symmetry breaking term to guide the system to the ground state you're interested in. Often one can pick a tiny magnetic field (uniform for a ferromagnetic state, staggered for a Néel state). This picture looks very clean for the kind of magnetic states I've discussed above, one's related by a symmetry of the Hamiltonian, since the symmetry allows us to pick our coordinate system as we like. (That's essentially what we're doing by adding a magnetic field - picking out the natural spin quantization axis.) Now, the picture would be less clear in a system with accidental (or maybe pathological) degeneracies between qualitatively very different states. In that case picking the wrong state likely leads to predictions that disagree with the experiment, so one could just try again.\nFor smaller systems, where superposition might be a reality, I'd probably try to stick with exact diagonalization techniques myself. People studying systems from class 3 tend to utilize very sophisticated approaches, see e.g. this paper. But based on your comment I think class 2 interests you more.", "976" ], [ "First of all, the SSH model does not have particle-hole symmetry. Particle-hole symmetry is an exact symmetry (at mean field level) reserved for superconductors and is an anti-unitary symmetry. A symmetric spectrum does not mean particle-hole symmetry.\nSSH model and end states\nLet me first explain a simple way to understand the topological end states. The SSH model is a 1D chain of dimers on which live spinless electrons that can hop from site to site: \\begin{equation} H = \\sum_n \\underbrace{t_1 c_{An}^\\dagger c_{Bn}}{\\textrm{intracell}} + \\underbrace{t_2 c{An+1}^\\dagger c_{Bn}}_{\\textrm{intercell}} + \\,h.c, \\end{equation} with bulk energy dispersion $E(k) = \\left(t_1 + t_2 \\cos k\\right)^2 + \\left( t_2 \\sin k \\right)^2$.\nConsider the strong-coupling limits:\n* $t_1 \\gg t_2$: This a molecular limit where all atoms in the chain form dimers. The spectrum of this chain is just $E = \\pm t_1$. Clearly trivial. No end states.\n* $t_2 \\gg t_1$: Now the atoms at the end of the chain are unpaired. Since the model has zero on-site energy, an electron on these ends has zero energy. The bulk spectrum is $E = \\pm t_2$ with two localized zero modes, one at each end.\nSymmetries and protection\nNote that a spectrum that is symmetric around zero energy is not necessary for the end states. The end states will just not lie at zero energy. In fact, the symmetric spectrum is artificial, since second-nearest hoppings introduce an asymmetry.\nHowever, what is a real symmetry of the chain, is inversion symmetry about the centre of a bond and spinless time-reversal symmetry. Moreover, the \"topology\" of the SSH system is protected by these symmetries.", "526" ], [ "In fact, it gives rise to a $\\mathbb Z_2$ classification.\nNo change in the Hamiltonian that respects inversion symmetry $H(-k) = \\sigma_x H(k) \\sigma_x$ and spinless time-reversal symmetry $H(-k) = H(k)^*$ and does not close the energy gap can destroy the end modes in the topological regime ($t_2 \\gg t_1$). Note that this forbids $\\sigma_z$.\nDirac Hamiltonian\nRecall the strong-coupling regime. In order to go from the trivial regime to the topological regime, you need to go through the point $t_1 = -t_2$ at which point the energy gap closes at $k=0$. So in order to change topology, the system has to become gapless. Near $k=0$, the Bloch Hamiltonian of the SSH model is given by the Dirac Hamiltonian: \\begin{equation} h = m \\sigma_x + t_2 k \\rightarrow m(x) \\sigma_x - it_2 \\partial_x \\sigma_y, \\end{equation} where $m(x) = t_1(x) + t_2$. At the closing of the gap $m=0$. Now consider a domain wall between two different phases (see figure below). At a domain wall $m(x)$ changes sign. In this case, there exists a normalizable zero mode localized at the domain wall: \\begin{equation} h \\psi = 0 \\Rightarrow \\psi(x) = \\exp \\left( -\\int_a^x dx' \\frac{m(x')}{t_2} \\right) \\begin{pmatrix} 1 \\ 0 \\end{pmatrix}, \\end{equation} where the lower limit $a$ fixes the normalization. This is the Jackiw-Rebbi model. You see that the condition for a zero mode requires a change of the sign of the mass $m(x)$. This mechanism, called band inversion, is generic for all symmetry-protected topological states such as topological insulators, topological superconductors, crystalline topological insulators, $\\ldots$.\nIn essence, the symmetries were necessary to restrict $h$ to only two Pauli matrices. In order to have a generic gap closing in 1D you can only have two Pauli matrices.", "526" ], [ "The realness of the interorbital coupling $t$ can indeed tell us something about the symmetries of the system. Here, it entails at least one symmetry: spinless time-reversal symmetry.\nConsider the Hamiltonian of non-interacting spinless particles that live on a periodic chain with two orbitals in each unit cell as in OP's example. In this case, the Hamiltonian can be block-diagonalized by using the periodicity of our system: \\begin{equation} H = \\sum_k \\begin{pmatrix} c^\\dagger_{k1} & c^\\dagger_{k2} \\end{pmatrix} H(k) \\begin{pmatrix} c_{k1} \\ c_{k2} \\end{pmatrix} \\end{equation} where $H(k)$ is a $2\\times 2$ block, labelled by the momentum $k$, called the Bloch Hamiltonian. Now assume that the system has time-reversal symmetry. This means that $[H,T]=0$ with $T$ the time-reversal operator. For spinless particles it is given by $T=K$ with $K$ complex conjugation with respect to the position representation (see e.g. <PERSON>). Since $T c_{k,i} = c_{-k,i}$, we find \\begin{equation} H = THT^{-1} \\Rightarrow H(-k) = TH(k)T^{-1} = H(k)^.", "526" ], [ "\\end{equation} In OP's example, a periodic chain of cells with no tunnelling between them is considered. Essentially an infinite amount of isolated atoms. The Bloch Hamiltonian is \\begin{equation} H(k) = \\begin{pmatrix} \\epsilon_1 & t \\ t^ & \\epsilon_2 \\end{pmatrix} \\end{equation} so that the total Hamiltonian $H$ is not time-reversal symmetric if $t$ is not real.\nAnother example which illustrates the effect of spinless time-reversal symmetry in a periodic system is given by graphene. Here, spinless $T$ and inversion protect the nodes in the band spectrum (Dirac points) locally since combined they forbid any $\\sigma_z$ term which would open the energy gap. The two Dirac points can only be destroyed if they merge in a time-reversal-invariant point of the Brillouin zone.\nGenerally, if time-reversal symmetry is present, the energy spectrum plotted as a function of $k$ (the so-called energy bands) is symmetric with respect to $k$: $E_i(-k) = E_j(k)$. However, the converse is not true since spatial symmetries such as inversion can also enforce a symmetric spectrum.\nSpinful time reversal\nIn the case of a half-integer spin system, it can be shown that the time-reversed state $T\\left| \\psi \\right>$ is orthogonal to $\\left| \\psi \\right>$ as a result of $T^2 = -1$ (<PERSON>' theorem). This means that the energy bands have to become degenerate in time-reversal-invariant points $k = -k + G$ where $G$ is a reciprocal lattice vector. A system with two bands is therefore always a metal. The simplest model for an insulator requires four bands.", "526" ], [ "The first thing that comes to mind is the fact that energy eigenstates have a periodic phase factor, $e^{iEt/\\hbar}$. In general we usually say that states are defined up to a phase factor, so for a single particle in an energy eigenstate we can ignore it, but this phase factor can manifest physically when you have a state which is a superposition of energy eigenstates, each with its own oscillating phase. A simple example of this which actually results in periodic behavior would be a spin-$1/2$ particle in a magnetic field. Such a system will have a Hamiltonian proportional to the Pauli spin matrix $\\sigma_z$.", "789" ], [ "So our time-evolution operator is $U(t) = e^{i\\omega \\sigma_z t}$. Recall that the Pauli matrices are idempotent, so when we Taylor expand this we can group our terms together and we will find\n\\begin{equation} U(t) = \\cos\\left(\\omega t\\right)+ i\\sigma_z \\sin\\left(\\omega t\\right) \\end{equation}\nFor eigenstates of $\\sigma_z$ this isn't particularly interesting. The $\\sigma_z$ will give us just a + for $\\vert \\uparrow \\rangle$ or a - for $\\vert \\downarrow \\rangle$ and of course the modulus of the state won't change but it will have a time-oscillating phase factor. Instead let's think about a superposition of such eigenstates, like $\\vert \\psi \\rangle \\equiv\\frac{1}{2}\\left(\\vert \\uparrow \\rangle + \\vert \\downarrow \\rangle\\right)$.\n\\begin{equation} \\begin{split} U(t) \\vert \\psi \\rangle = \\frac{1}{2}\\cos\\left(\\omega t\\right)\\vert \\left(\\vert \\uparrow \\rangle + \\vert \\downarrow \\rangle\\right) + \\frac{i}{2} \\sin\\left(\\omega t\\right) \\left(\\vert \\uparrow \\rangle - \\vert \\downarrow \\rangle\\right) \\ = \\frac{1}{2} e^{i\\omega t} \\vert \\uparrow \\rangle + \\frac{1}{2} e^{-i \\omega t} \\vert \\downarrow \\rangle \\end{split} \\end{equation}\nNot incidentally, this state was chosen to have a spin of $+\\hbar/2$ along the $x$ direction, but we can see in the above equation that when we evolve it in time we reach a point where it will have spin $-\\hbar/2$ along the $x$ direction, when $\\cos(\\omega t) = 0$ and $\\sin(\\omega t) = 1$, so the expectation value of the $x$ spin of this particle is periodic.\nBecause the Hamiltonian operator is Hermitian by assumption, it can be diagonalized and the operator exponential can be rewritten as a manageable <PERSON> series, but this nice periodic form only works because the square of our Hamiltonian is proportional to the identity matrix, so we could group terms in the <PERSON> expansion to give us a cosine multiplied by the identity and a sine multiplied by the $\\sigma_z$ operator. In general this procedure does not work out quite as nicely, but you can always think about the interference of the phase factors I mentioned in the first paragraph.", "66" ], [ "META-POLITICAL NOTE: <PERSON> WOULD DELETE THIS ANSWER, AS INSUFFICIENTLY UNREFERENCED. DO NOT VOTE FOR <PERSON>\nYou should understand it in 1d first, because it's essentially a 1d phenomenon. <PERSON> and <PERSON> unfortunately have a fundamental misconception about this, and they say wrong things throughout their paper. Here are the false claims:\n* They claim that a line of Na atoms in 1d do not have a purely electronic instability if the ions are clamped in place. This is true, but it's implying falsely that someone expected otherwise. The <PERSON> instability is by definition an ion motion, and it obviously can't happen in a strictly periodic lattice (see below). They say the same thing about the realistic DFT simulations of real CDW materials, that the electrons 'even when prompted by being artificially placed in a periodic charge configuration relax to the symmetric state\". Again, this shows a confusion about the origin of CDW configurations.\n* They falsely claim \"In the <PERSON> picture, lattice distortion is a secondary effect that arises in response to an electronically driven charge redistribution that would occur regardless of whether or not the ions subsequently shift from their high symmetry positions.\" No.\n* The claim \"In real materials, the electronic and ionic instabilities always occur simultaneously.\" This is true, but it is exactly what <PERSON>' argued.\n* They falsely claim that the wavevectors which produce experimental CDW's are not those which best line up the Fermi surface with itself (this is your question, see further below).\nThese confusions all come from one core misunderstanding--- they think the electrons organize themselves asymmetricially first, and then the ions follow along. This is incorrect. The ion positions determine the ground state of the electrons, and it is the reduced energy of the electrons in the deformed position that leads the CDW configuration to form.\nHaving said that, here is...\nPeierls 1d argument\nImagine a line of atoms on integer positions sharing their electrons to make a conduction band. You have exactly one electron per atom, and the k-vectors range from $-\\pi$ to $\\pi$.", "70" ], [ "The electrons are split in spin 50/50, so you get filling of the states in the first band up to exactly $\\pm \\pi/2$, and that's the Fermi surface (two points). This is called a half-filled band, since the states are filled duplicately until the exact half-way point.\nIn this situation there is an interesting phenomenon. Imagine that you deform the lattice by shifting all the atoms in the odd positions to the right by $\\epsilon$. The new lattice is strictly only periodic with period 2 now, so the k vector range for the deformed lattice is reduced to $[-\\pi/2,\\pi/2]$. The band from before is now split into two bands of the longer period system, and most importantly, all the electrons are put in the lower band after the deformation, because the original band was half-filled.\nThe splitting of the old band is accompanied by lowering the energies of the electrons at the edge of the band, the dispersion relation E(k) for the original band, which was linear at $\\pi/2$ before, is now split into two hyperbolas, one higher than the other. If the electrons filled up to $\\pi/2 + .001$ instead, this wouldn't lower the energy, because the electrons in the lower band would lose, and the electrons in the upper band would gain a nearly equal amount.\nBut the Fermi surface is exactly at $\\pi/2$, so the electronic energy is reduced by this deformation. The shape of the E(k) function is a hyperbola, and it's integral gives $\\epsilon^2\\log(\\epsilon)$ reduction in energy. The $\\log(\\epsilon)$ is important, because it means that this will always beat the elastic energy cost of the deformation, which goes as $\\epsilon^2$, so that this represents a true instability.\nNote that the atomic motion is causing the electrons to reconfigure, so the critique in the paper you give is baseless. The 1d lattice is distorted, and this is what makes the electron energy go down. No distortion, no reduction in energy.\nThe 1d thing becomes an insulator after the band opens, because you opened a band gap, so you can't conduct electricity by giving electrons momentum. But you can still conduct electricity in a strange way, also described by <PERSON>.", "969" ], [ "The name DMRG is somewhat of a historical accident, and its modern day incarnations are not directly linked to the renormalization group or phase transitions. Instead, it is better understood as a variational technique based on matrix-product states (MPS) ansatzes. Still, there is a historical link between the two tools, and it can be useful to know about it.\nBefore continuing, your description of RG is a bit restrictive. What you write is RG as it's applied to critical phenomena and phase transitions, which, as you've found already is a very rich field. However, more generally RG is the systematic study of a system as a scale is changed.\nSome history\nAfter introducing RG for phase transitions, <PERSON> introduced a numerical RG technique with the aim to find the groundstate of a 1D problem. It basically boiled down to repeatedly diagonalizing the Hamiltonian of ever larger finite size blocks, keeping the lowest set of states at each iteration. (The block size playing the role of the scale for RG purposes.) This method worked wonders for the <PERSON> problem, where the coupling to an impurity spin falls off with distance, but fails for ordinary spin models - and famously also for the problem of a particle in a box.\nThe reason it fails is that keeping only the lowest energy states is not the right method of truncating the Hilbert space basis.", "28" ], [ "Still, we obviously want some way of truncation, or else any hope of large scale computer calculations goes out the window. This is where DMRG originally developed from during the 90s. <PERSON> invented it with the idea of throwing away states with low probability, which is naturally framed in the language of density matrices. Hence, the origin of DMRG is real-space block RG.\nBut when you have a changing system size, it's reasonable to think of all this in terms of bipartite entanglement. That is, we can divide the lattice into a system part and an environment part, and calculate the entanglement between the two subsystems. Then DMRG can be reformulated as a way of throwing away high entanglement states, and keeping low entanglement ones. It turns out that most ground states have low entanglement, and are efficiently expressed in MPS states. When this was realized in the 2000s, the RG roots of DMRG were largely shoved under the rug, and DMRG was reformulated as a variational method using a basis of MPS states.", "783" ], [ "Lagrange multipliers in quantum systems are usually (always?) implemented on the level of expectation values - often specifically ground state expectation values. That's also the case for these two papers. So, given an extended Hamiltonian $$ H'= H_\\mathrm{MF}+H_\\mathrm{constraints}$$ where $H_\\mathrm{constraints}$ contains the Lagrange-multiplier-enforced constraints, we want to find a ground state of $|\\psi\\rangle$ of $H'$ that satisfies the constraints. For reasonable constraints this will be possible by finding appropriate values for the Lagrange multipliers. Note that $|\\psi\\rangle=|\\psi_0\\rangle+|\\delta\\psi\\rangle$, where $|\\psi_0\\rangle$ would be the ground state of $H_\\mathrm{MF}$. That is, ground state expectation values $\\langle\\psi|\\hat{O}|\\psi\\rangle$ of some operator $\\hat{O}$ will depend on the Lagrange multipliers $a_i$, and we can tune the $a_i$ until we find expectation values compatible with the desired constraints.\nOf course, we could use the same approach for excited states, but then we i) would expect different values for the Lagrange multipliers, and ii) might require additional constraints to make sure the state is orthogonal to lower-energy states. In other words, <PERSON>'s Lagrange multiplier terms are enough to enforce the constraints on the ground state, but you shouldn't expect them to be enough to enforce the constraint on the full Hilbert space. Compare the situation with the most familiar example of a Lagrange multiplier in stat. mech. or condensed matter systems - the chemical potential $$\\mu \\left( \\int |\\Psi \\left(\\mathbf{r}\\right)|^2 d\\mathbf{r} - N \\right). $$ It can be used to enforce a fixed particle number $N=<\\hat{N}>$ in a thermal state, but excited states are allowed to have other occupations.\nAdditional comments:\nAs you note, <PERSON>'s constraints are site-dependent. This is often rather inconvenient, particularly in numerical calculations.", "976" ], [ "Hence, often when searching for a translationally invariant mean field solution, the site-dependent local constraints can be relaxed to global ones, i.e. you might go from $\\sum_i \\lambda_i \\left( f_{i\\sigma}^\\dagger f_{i\\sigma} - 1\\right)$ to $\\lambda \\left(\\sum_i f_{i\\sigma}^\\dagger f_{i\\sigma} - N\\right)$, which now enforces half-filling on average. This is commonly done in the $t-J$ model theory for high-$T_c$ superconductivity, for example, see e.g. this review. Ideally, using the relaxed constraint can allow an easier path to a solution that satisfies the local constraints.\nIt might also be instructive to look at how one might solve such a constrained mean-field problem numerically and self-consistently. One algorithm would be\n1. Start by making initial guesses for the values of the mean field parameters (e.g. $\\chi$)\n2. Find values for the Lagrange multipliers such that the constraint is satisfied\n3. Calculate new expectation values ($\\chi_{current}$)\n4. Update guesses for the mean field parameters (e.g. by conservative mixing $\\chi_{new}=(1-x)\\chi_{old} + x\\chi_{current}$ where $x$ is small)\n5. Return to step 2, and repeat until the parameters converge.", "915" ] ]

[ 9356, 3275, 4832, 9504, 4220, 721, 5829, 3038, 7304, 2839, 9487, 4650, 958, 4534, 748, 10049, 4775, 809, 4823, 2092, 11036, 2768, 5055, 8893, 6647, 8447, 1941, 9469, 10644, 5589, 8383, 11030, 6148, 8883, 5429, 2421, 10852, 6414, 9926, 10950, 4683, 10724, 9220, 3073, 10375, 3230, 11311, 7259, 6467, 9172, 7353, 4875, 5200, 3311, 8758, 7014, 6507, 8221, 4700, 4860, 5786, 10660, 975, 5943, 5237, 10820, 2731, 9473, 10461, 4064 ]

[ [ "The Magnificent Seven\n“What we lost in the fire we'll find in the ashes.\"\nThe Magnificent Seven is a 2016 American Western action film directed by <PERSON> which follows seven gunmen from a variety of backgrounds who are brought together by a vengeful young widow to protect her town from the private army of a destructive industrialist.\nNo idea why I decided to check this one out tonight but I had a hankering to get around to it for some time, admittedly just because of the cast.\nI haven’t seen the original 1960 version of this story (I will get around to it), but last year I checked out Seven Samurai and loved it and so I went into this with good hopes.\nI actually loved this too — it’s not quite cinematic art like Seven Samurai but as a version of the tale, it was really likeable and enjoyable.\nMuch of this is down to the cast that, whilst not given the time that the other characters are, still manage to stand out — <PERSON> is straight up perfect as a <PERSON> redux as the pair have similar acting tics, and both fill the same space very well.\nThe supporting cast is also solid, even <PERSON>, though my favourites were <PERSON> and <PERSON> who were definitely gay (side note: this is the second gay western I’ve seen <PERSON> in and this one isn’t canon but he still has more chemistry with <PERSON> than he did <PERSON>. Go figure).\nI also appreciate that <PERSON> went out of his way to make this film diverse and it really works, especially since the film doesn’t magically gloss over racism but it gives the characters nuance and depth.\nI called <PERSON> milquetoast in one of my other reviews and perhaps I judged him too harshly — he’s very competent and this film looks gorgeous.", "378" ], [ "It also helps that it’s backed by a wonderful score, part of which was composed by the legendary <PERSON> in his final credit before he died during the production and was subsequently followed up by his friend <PERSON>.\nOn the whole, I actually really loved this, mainly for the cast. It’s not Seven Samurai but as a film on its own merits, it’s very enjoyable. Recommended.", "529" ], [ "Soul of the Sword\n“Nothing can stop me.”\nSoul of the Sword is a 1978 wuxia film directed by <PERSON> which follows a lone swordsman willing to do whatever it takes to become the number one swordsman.\nChecked this one out as I was craving some more <PERSON> goodness and this was definitely one of his more complex roles, in that he plays a complete and utter bastard — seriously, I’ve seen him play a villain in Blood Brothers but even then, he wasn’t as hateable as he was here.\nHe’s also very compelling, in that his role here is almost a <PERSON>-esque role in that he becomes haunted by the ghosts he leaves behind, too driven by his own pride and goals that it is bound to end in tragedy.\nThough the film boasts an unfortunate misogynistic streak and one of <PERSON>’s worst wigs, it does also feature one of <PERSON>’s finest performances. Here, he isn’t the wuxia hero but as mentioned, more a <PERSON> type and even gave me <PERSON> in Throne of Blood vibes.", "378" ], [ "It’s an intense, ugly performance that is very gripping and means the admittedly underdeveloped supporting cast (particularly his love interest, who seemingly has Stockholm Syndrome) is forgivable. It was good seeing <PERSON> here though.\nThe film is also visually spectacular, with some great imagery and music that helps set up the character driven story.\nOverall, this was a very solid, if hard to watch Shaw Brothers flick. Content warning is advised but I recommend.", "378" ], [ "Ninja Assassin\n“Weakness compels strength. Betrayal begets blood. This is the law of the Nine Clans.”\nNinja Assassin is a 2009 martial arts film directed by <PERSON> which follows a disillusioned assassin looking for retribution against his former mentor.\nHaving a ninja triple feature today and this is the first — you’ll see the other two popping up later. Ninja Assassin is a film I’ve wanted to get to for some time mainly because of <PERSON> as the villain but never got around to it until now.\nI straight up had a blast with this — it’s very sleek in that late 2000s style but is also absurdly violent, harkening back to the likes of <PERSON> and <PERSON> and Cub.", "995" ], [ "Though I wish it didn’t rely on CGI blood as much, it definitely commits to the hyper violence and is a rollicking good time with its action.\nSouth Korean pop singer <PERSON> is our ninja here and does a solid job (I wonder if the character name <PERSON> is a reference to <PERSON>, the first ninja in film?) even if it does mean that in a film with Japanese ninjas, there are only two Japanese actors, those being <PERSON> and <PERSON> (who I got a kick out of seeing after watching Monarch: Legacy of Monsters this month).\nElsewhere in the cast, we have <PERSON> of Die Another Day and The Fast and The Furious, joining <PERSON> and <PERSON> in what is an unofficial Fast film about ninjas. In seriousness, <PERSON> is great here even if he doesn’t have too much screentime.\nSpeaking of <PERSON>, <PERSON> herself is also here and whilst I wish they’d committed to a romance here (got real Romeo Must Die vibes), she’s great and actually gets involved in the action somewhat without having a ridiculously overpowered contrivance.\nLastly, let’s talk about the Master Ninja himself, <PERSON> — it feels like coming full circle from him being the villain of Enter the Ninja to this and he’s straight up great here, obviously he’s not flipping around but holds his own very well and is still very believable as the aged ninja. Probably one of my favourite performances from him as well, he brings a grit to his role that is different from the overwrought intensity of his most famous roles.\nOf course, as mentioned, the action here is stellar and I liked the variety of weapons shown — the police station attack is a little similar to the previous year’s Ninja but is so cartoonishly violent that I can’t help but praise it.\nOverall, this was a fun start to my ninja triple feature. Recommend.", "378" ], [ "The Beekeeper\n“To bee or not to bee?”\nThe Beekeeper is a 2024 American action thriller film directed by <PERSON> which follows one man's brutal campaign for vengeance which takes on national stakes after he is revealed to be a former operative of a powerful and clandestine organization known as \"Beekeepers\".\nEveryone knows I love a good, cheesy horror film and so the trailer for The Beekeeper was pretty much catnip for me. From its self-serious tone to the one liners, I knew I’d at least have fun with this.\nUnsurprisingly, The Beekeeper is a delight — a capital B B-Movie (or should I say Bee Movie) with its tongue firmly in cheek. Though it’s revenge trappings may recall <PERSON>, I felt it had even more in common with an early 90s <PERSON> flick, particularly Hard to Kill.\n<PERSON> is essentially the fuckin’ Terminator here and though his lack of taking a punch bugged me at first, once he finally takes some hits from a henchman with the funniest accent I’ve ever heard, it’s great.", "995" ], [ "<PERSON> also attempts an American accent but even the film knows it’s bad so comes up with an excuse for it.\nThe villains are also just comically inept, and the committed performances by <PERSON> and <PERSON> are campy as hell — shoutout to the dudes playing the scammers too, they were hilarious.\nOn the whole, The Beekeeper is a fun actioner which well-deserves the buzz. Take your hive (or honey) and see it on the big screen and bee-lieve the hype. I’m so sorry.", "585" ], [ "Shaolin Mantis\n“I look forward to trying your shadowy fists!”\nShaolin Mantis is a 1978 Shaw Brothers film directed by <PERSON> which follows a young scholar who infiltrates a family and has to learn martial arts based on the praying mantis.\nMissed seeing my boy <PERSON> in a leading role and so decided to put this one on — it’s weird, I’ve seen his early <PERSON> works and his late 80s work but that middle stretch is still a little bit of a blind spot for me.\nThis was pretty good — I’ll admit, <PERSON> playing the mother of <PERSON>’s love interest when she’s not only younger than him but has played his love interest multiple times really threw me at first but once I got past that, I had fun.\n<PERSON> is his typical charming self and the action sequences, though not my favourite with him are strong (I got a kick out of him fighting <PERSON> and <PERSON>).\nIn terms of <PERSON>, I didn’t like this as much as Dirty Ho or <PERSON>, but his direction was strong, even if the storytelling felt somewhat slow at times (I did appreciate that final twist).\nOn the whole, this was solid enough, recommended.", "378" ], [ "<PERSON>\n“You can beat me, but don't call me a bastard.”\nBastard Swordsman is a 1983 wuxia film which follows a bullied outcast who must stand up for his kung fu school when they find themselves under attack.\nWanted to check out more <PERSON> (because he’s awesome and I’m sick so wanted something fun) and this was one I’d heard good things about.\nIn a lot of ways, the shyness and angst of <PERSON>’s character kinda reminded me of <PERSON> in The New One-Armed Swordsman, only a lot less gay — he’s subtle and withdrawn and I loved his performance here, it well reflects his also reserved character in Duel to the Death, but the differences between the characters are also staggering.\nIt’s also a wuxia that leans more into the high concept and wild special effects, though isn’t as weird as something like Zu: Warriors from the Magic Mountain. The fights here are very much the flying through the air, gravity defying wire work as well as throwing lasers at each other, which was real fun.\nOn the whole, whilst I prefer <PERSON>’s other wuxia of that year, this was still a nice underdog story.", "378" ], [ "Revanchist\n“Go to hell, pig.”\nRevanchist is a 1994 Taiwanese action film directed by <PERSON> which follows the revenge mission of a prisoner after his brother is killed and lover is forced to marry a gangster.\nI said after watching 21 Red List that I was going to check this out next and that meant immediately as I pulled this up on ok.ru instantly after.\nRevanchist is another slice of Heroic Bloodshed, but with a much nastier feel than 21 Red List, feeling about as sleazy as your average CAT III film (in fact, parts of this reminded me of Full Contact in a strange way).\nThough his onscreen appearance is essentially a cameo (loving his beautiful mullet though), <PERSON> returns to provide the action choreography and one ups himself from 21 Red List, something I wasn’t sure was possible.\nSeriously, the action here is straight up insane, viscerally violent and beautiful to watch in that classic Hong Kong way.\nI also liked the cast — much are the same performers from 21 Red List but once again, the story was genuinely compelling here, with a good helping of nihilism.\nOverall, I highly recommend you check this one out, it’s violent as hell but worth it for <PERSON>’s choreography.", "378" ], [ "The Rebel\n“Murderers? How do you call us ‘murderers’ when we're only fighting for our homeland?\"\nThe Rebel is a 2007 Vietnamese martial arts film directed by <PERSON> which follows an agent in French-occupied Vietnam who falls in love with the daughter of a rebel.\nDecided to check this one out after watching <PERSON> episode on <PERSON> The Art of Action series and seeing the absolutely awesome CGI head kick and this is actually my first ever Vietnamese film.\nI actually really loved this — it’s your typical historical epic with a central romance but it also features people kicking colonialists in the face.\n<PERSON> and <PERSON> are our leads and not only are they straight up gorgeous (look, my reviews can be shallow), they both also kick a lot of ass. I’ve seen <PERSON> in The Princess and every time I see her, I get more pissed that The Last Jedi wasted her.\nSimilarly, <PERSON> is someone I’ve seen in Cradle 2 the Grave and The Protector and though he’s awesome in those, it’s nice seeing him in a leading role and learning about that CGI head kick gives me respect for him as a visual effects artist too.\nThose pair have great chemistry and again, both are aesthetically pleasing to look at so it makes the admittedly cheap look and dark cinematography forgivable.\nI also enjoyed <PERSON> as our villain, he portrays him with menace but also some depth, making him compelling and his fight with <PERSON> and <PERSON> is great.\nUltimately, I really liked this — it’s definitely more a historical film than an outright martial arts film but I definitely recommend checking it out.", "995" ] ]

[ 1312, 8912, 5815, 9642, 11103, 3061, 954, 4114, 1515, 3308, 3008, 5750, 4335, 9673, 7677, 1600, 6430, 9086, 6031, 10223, 6960, 2005, 9571, 10719, 8448, 2225, 8861, 8266, 3127, 7341, 4386, 5135, 3808, 10612, 9850, 10314, 5184, 8296, 10350, 1581, 7620, 5491, 2468, 3766, 1280, 10713, 5460, 3949, 6785, 10934, 935, 2029, 2381, 2164, 3735, 2750, 6298, 2876, 5483, 5081, 10953, 10778, 6951, 10055, 4360, 9517, 927, 8615, 8659, 3463 ]

[ [ "No there were 12 like the Enterprise (Constitution class) at the time of the episode \"Tommorrow is Yesterday\" when <PERSON> utters the line: \"There are only twelve like it in the fleet.\"\nThe Star Trek Writer's guide established there were fourteen Constitution Class starships: Constitution, Constellation, Enterprise, Yorktown, Lexington, Farragut, Republic, Intrepid, Exeter, Hood, Excalibur, Valiant, Kongo, Potemkin. The original AMT model decal sheet validates these names.\nThe Constitution Class had been around for at least 13 years and probably longer (The Menagerie) and <PERSON> had served aboard at least two of them before assuming command of the Enterprise. The USS Republic (Court Martial) and the USS Farragut (Obsession.)\nIt is almost certain the Farragut was lost or destroyed when it encountered the Cloud Creature, and that would make <PERSON>'s statement in Tomorrow is Yesterday true when he said it. There were only twelve like it (that were left) in the fleet.\nThe Star Trek Reference manual lists four as destroyed. We saw at least two of them destroyed, Intrepid in Immunity Syndrome and Constellation in Doomsday Machine. These episodes occurred after Tomorrow Is Yesterday. We heard of the destruction of Farragut in Obsession.", "126" ], [ "We also probably saw the destruction of the Excalibur in Ultimate Computer but it was never established that it was destroyed beyond salvage.\nThis leaves the Valiant. This is problematic. It may be bad writing. Other than the ship named 'Valiant' that disappeared two hundred years before the episode 'Where No Man Has Gone Before' we saw no Constitution class USS Valiant. We did however see a USS Defiant (Tholian Web) that wasn't on the writer's guide list. Like the other ship names used from history there was an actual British battleship named Valiant. There was never an actual ship named 'Defiant.' There was a fictional HMS Defiant in the film 'Damn The Defiant' I think somebody messed up, meant to type Valiant but chose to type Defiant instead and it became hard to explain canon.\nEither way there were fourteen original Constitution Class and thirteen left when <PERSON> made his statement in Tomorrow Is Yesterday.\nAnd they were all Constitution class. The model gave you a Constitution class starship and 14 names to choose from.", "126" ], [ "You are referring to the Bridge Officer's Test in the episode Thine Own Self.\nYou take the Bridge Offricer's test in order to qualify to serve on the bridge as the commanding officer, under normal circumstances. We have seen <PERSON> take command of the bridge in the episode Disaster, before she took the test, because it was an emergency situation, and she was still the highest ranked officer able to do so.\nThe Bridge Officer's Test does not seem to directly correspond with rank. You almost certainly need to take it to be qualified to achieve a certain level of rank, but <PERSON>, as only a Lieutenant Commander, is third ranking officer on the bridge normally, and therefore has surely already taken the Bridge Officer's Test. We have seen him take command of the Enterprise in Gambit Part 2 and Redemption Part 2, although you might argue these were unusual circumstances, in the case of Gambit, in Redemption, <PERSON> receives temporary command of the Sutherland, which is pretty solid evidence he has taken the test.\nIt is my personal conjecture that Star Fleet functions like real life military where high rank may be achieved while not performing normal officer/commanding duties, if you perform a highly specialized job, such as doctor or counselor, hence the higher rank of <PERSON> and <PERSON> after they took the Bridge Officer's Test.\nFinally, I'd like to say that the point of To Thine Own Self was that the Bridge Officer's Test was not easy for <PERSON>.", "865" ], [ "She failed many times, and when she finally passed, she said:\nI knew that was part of being in command, and I thought I'd prepared for it. But when the moment came, I hesitated. Maybe you were right, maybe I'm not cut out for this.\nAs shown in the episode, not everyone chooses to take the Bridge Officer's Test. It requires you to be able to make decisions like sending someone to die. <PERSON>, if he had not taken the test (but as far as I know, there is nothing to show that he hasn't) may have not because he prefers to stay in engineering and not make command decisions.\nI will note that we actually have seen <PERSON> command the Enterprise in the episode Arsenal of Freedom, which is likely due to his having taken the Bridge Officer's Test, but as it was an emergency situation with no higher ranked personnel present, it could have been due to the situation, like how we saw <PERSON> take command without having taken the test in Disaster, and so whether he has taken the test isn't entirely clear.", "865" ], [ "According to the Original Series Writer's Guide:\nWe invented \"Stardate\" to avoid continually mentioning Star Trek's century (actually, about two hundred years from now), and getting into arguments about whether this or that would have developed by then. Pick any combination of four numbers plus a percentage point, use it as your story's stardate. For example, 1313.5 is twelve o'clock noon of one day and 1314.5 would be noon of the next day. Each percentage point is roughly equivalent to one-tenth of one day. The progression of stardates in your script should remain constant but don't worry about whether or not there is a progression from other scripts.", "126" ], [ "Stardates are a mathematical formula which varies depending on location in the galaxy, velocity of travel, and other factors, can vary widely from episode to episode.\nThe Writer's Guide for The Next Generation stated:\nA stardate is a five-digit number followed by a decimal point and one more digit. Example: \"41254.7.\" The first two digits of the stardate are always \"41.\" The 4 stands for 24th century, the 1 indicates first season. The additional three leading digits will progress unevenly during the course of the season from 000 to 999. The digit following the decimal point is generally regarded as a day counter.\nDeep Space Nine began with 46379.1, corresponding to the sixth season of Star Trek:\nStar Trek: Voyager began with stardate 48315.6 (2371), one season after TNG had finished its seventh and final season. As in TNG, the second digit would increase by one every season, while the initial two digits eventually rolled over from 49 to 50, despite the year 2373 still being in the 24th century.\nStar Trek: Nemesis was set around stardate 56844.9, which is so far the highest stardate to have been mentioned in the Star Trek canon.\nTo answer the original question, there was never any rule devised by writers to explain what date was used, so one can only assume they used some sort of GMT (Greenwich Mean Time) across the galaxies, based on a focal point (which may or may not have been the Federation headquarters).", "126" ], [ "Edited to add in the correct info about the first minority super hero.\nIn DC Comics All-Star Western #117 published in February 1961 the first Native American superhero appeared with the horrible name of Super-Chief.\nA summary of his origin can be found here The Crowning of Super-Chief. Super-Chief appeared in the next two issues and then the series was cancelled.\nMarvel introduced the Black Panther in Fantastic Four #52 in July of 1966.\nHowever, it may not be accurate to say that the character is a minority. <PERSON> is in reality <PERSON>, King of the fictional African country of Wakanda. Although he would be seen as a minority in the United States due to being African he is not part of teh African-American minority in the US.\nDC introduced its first minority superhero the Black Racer in June 1971 in New Gods #3.\nThe Black Racer may not really qualify as a superhero though. The character is part of <PERSON> Fourth World series. The corporeal form of the Black Racer is an African-American Vietnam veteran named <PERSON>.", "167" ], [ "When <PERSON> brought the war of the New Gods of New Genesis and Apokolips to Earth the Source, a sort of God like universal shared consciousness, contacted <PERSON> and turned him into the deity known as the Black Racer. The Black Racer's job is to collect the souls of the New Gods when they die and deliver them to Hadis the Fourth World version of Hades.\nSo where does that leave us if we ignore these two entries. Marvel's next African-American hero was the <PERSON> introduced in Captain america #117 in September 1969.\nThe <PERSON> is the alter ego of <PERSON>. He was trained by <PERSON> after he fought beside him against a group of former Nazis working with the Red Skull. The Falcon did have one definite first in that the word 'Black\" wasn't part of his superhero name.\nDC's next black superhero appeared in Green Lantern #87 published in December 1971.\nThis is the previously noted <PERSON>. Artist <PERSON> resisted the powers that be who wanted to name the character <PERSON>.\nHowever, all that being said these were not the first non-stereotyped or non-racist African-American characters in comics. These were just the first superheroes.", "167" ], [ "The answer to this question is generally not a simple one.\nThe specific Q entity portrayed by <PERSON> has made references to the true nature of the Q and their existence starting from his first appearance in the TNG episode \"Encounter at FarPoint\"; that the human mind is not capable of comprehending the true nature of much of the universe (the crew's confusion about the nature of the events supports the theory).\nIn fact, every time Q appears something happens that is well beyond human comprehension and in one occasion the TNG crew find themselves in Sherwood Forest.\nIn the episode \"Deja Q\" <PERSON> character has been stripped of most of his abilities by the other Q and is struggling to understand what the beings he has been \"tormenting\" are actually capable of. He says to \"change the gravitational constant of the Universe\" as a solution to a problem because altering the universe, and all of the subspace and technology within it, is something that would otherwise have been trivial for a Q. Changing the universal constant, however, is well beyond anything Star Fleet and their understanding subspace can achieve so they attempt to change the moon's gravitational constant instead (Note that the Federation often alters the mass, inertial and gravitational characteristics by pushing the ship and its contents into a subspace state).\nIn VOY episodes such as \"The Q and the Grey\", the Voyager crew end up visiting the continuum and it is explained that the reason the continuum seems to be a re-enactment of the American Civil War (with Voyager nowhere to be seen) is that their human minds are not capable of understanding what is really going on so it merely appears in simplified terms (usually something out of Earth history).", "837" ], [ "By contrast subspace is depicted as a region through which space ships and other objects can travel (not wooded or desolate land in the limited human understanding). Further it is also referenced that the Civil War style weaponry that everyone is firing at each other are actually disrupting normal space and causing supernovae all over the place that are actually apertures into the continuum and that Voyager can only enter by flying through the Supernova that occurred in the aftermath (likely what the shield was needed for). I believe <PERSON> makes a reference that they should go nowhere near the actual business end of the weapons considering what it would do to a human if it can actually make him seem to \"bleed\".\nWhat the writers seem to be getting at here is an that there are a very limited number of effects that can actually be visually produced by any character (either in universe or by the show's special effects crew); whatever coincidence there are in appearances the Q are NOT using any method or concept known to the Federation nor is the continuum anywhere that the Federation would be able to name. The Q ARE however often seen appearing on ships within subspace (Deja Q, The Q and the Grey and several others) and capable of using subspace techniques and technologies to do what they desire should they so choose.", "963" ], [ "I think it's rather easy to find out an order to watch the series. I take the Enterprise series and the new Star Trek movie as being an alternate universe. This is because of the events of First Contact would have altered the future even if they were small changes. The fact that TNG crew made contact with key figures that would shape the future and exposing them to future technology started a chain reaction of an alternate universe. Events in the Enterprise series shows signs of this alternate universe i.e <PERSON>'s speech clearly showing the <PERSON> from First Contact and not the missing one in space from TOS episode. The destruction of Florida in ENT which I consider to be quite significant like the destruction of Vulcan in the new Star Trek movie has no mention in future canon in TOS, TNG, DS9 or VOY which makes me believe it did not happen in their version of the past.", "837" ], [ "The events of the crew of ENT on board TOS enterprise is not their own future but an alternate future for them which is in fact the time line of TOS. Therefore I do not include ENT in the canon of TOS, movies TNG, DS9 and VOY but as the start of the alternate universe that leads into the latest movie.\nWhen <PERSON> and <PERSON> travel back in time in the Star Trek movie i think they not only go back in time but also to the alternate universe established by ENT. This would account for the technological differences to TOS. Obviously further changes to the time line are made during the movie. Also Captain <PERSON> is mentioned in this movie when the future <PERSON> and young <PERSON> meet <PERSON> which strengthens the ties between ENT and the movie being from the same alternate universe. The external design and interior of the USS Kelvin more closely resembles a future looking ship of the USS Enterprise from ENT than a past ship of TOS.\nYou could also go as far as saying that a more technological alternate universe was started during the movie \"The Voyage home\" when <PERSON> provides the information for warp speed on the computer. This could have sped up the development of future technologies by decades.\nIn conclusion I therefore watch\n* TOS (TV)\n* The Motion Picture (Movie)\n* Star Trek Movies 2-6 (Movie)\n* TNG (TV)\n* Deep Space 9 (Start after the 5th season of TNG and watch them along side each other) (TV)\n* Voyager (Start right after the end of TNG and watch along side DS9) (TV)\n* Generations (Movie)\n* First Contact (Movie)\n* Insurrection (Movie)\n* Nemesis (Watch sometime in the second season of Enterprise) (Movie)\nIf I am interested in following the alternate universe I only watch\n-First Contact (Movie)\n-ENT (TV)\n-Star Trek (Movie)\nor\n-Movies 1-6\n-Generations (Movie)\n-First Contact (Movie)\n-ENT (TV)\n-Star Trek (Movie)", "837" ], [ "Because the ship was assigned to Sisko/DS9 and wasn't autonomous in the same way other starships were.\nEven though the Defiant was designed to be a warship, the project was abandoned and the unfinished prototype had never been put in use. <PERSON> requests it with the sole purpose of deterring a Dominion attack by showing them that DS9 can defend itself if necessary. The Defiant was a flashy ship with a lot of teeth so <PERSON> thought he could show they were prepared to defend DS9 if they had to.\n<PERSON>: You'll have complete access to the ship evaluation reports but to put it simply, it's overgunned and overpowered for a ship its size. During battle drills, it nearly tore itself apart when the engines were tested at full capacity.\n<PERSON>: And this is the ship that Starfleet sends us to fight off an attack by the Dominion?\n<PERSON>: We're not going to fight the Dominion, Major. At least, not yet anyway. Our mission is to take the Defiant into the Gamma Quadrant and try to find the leaders of the Dominion, the Founders.", "126" ], [ "We have to convince them that the Federation does not represent a threat to them.\n<PERSON>: What if they don't believe us?\n<PERSON>: That's why I asked for the Defiant. She may have flaws, but she has teeth, and I want the Dominion to know that we can and will defend ourselves if necessary.\nDS9: The Search Part I\nGiven DS9's strategic value to the Dominion, the Federation (and showrunners, of course) felt that it was ridiculous to expect DS9 to be able to defend itself using only runabouts.\nAt one point, <PERSON> and I were sitting around after the '<PERSON>' episode had been filmed. We were looking at dailies and said, '<PERSON>, we're blowing up Galaxy Class starships; these guys are tough, and all we have are these freaking runabouts' [....] We had to come up with a ship to combat [the Dominion].\"\nCaptains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 79\nThe Defiant was intended to complement DS9's fleet of runabouts, giving them a faster, stronger ship to perform away missions and protect DS9 from the Dominion. The show's producers even referred to it as \"a beefy runabout.\" (Star Trek: Deep Space Nine Companion, p. 162)\nAs such, it made sense to be piloted and operated as an extension of the space station in the same way normal runabouts were.", "126" ], [ "Okay. My thoughts on this.\n1. I don't really give two craps what any of the writers or producers are saying about. Simply saying it doesn't make it so. It still needs to match with good evidence.\nThat being said, I think the stardate argument is weak. Throughout Trek, stardates were used to keep time when ships were traveling faster than light. It was not always consistent across the various shows. Therefore, you can't always derive an exact year from the stardate.\nThere are some things we do know though. There is certainly a point in which the timelines diverged. That was before the Kelvin was destroyed. This means that yes. The Kelvin itself, even though it does not resemble anything we saw in the Prime Timeline, is indeed a Prime starship. Originally.\nHowever, the appearance of the Kelvin is not necessarily the problem. It's really the apprarance of the rest of the ships in the Kelvin timeline. These were very different and a bit more advanced than the ones of the Prime Timeline (let's not forget the Enterprise's big copper deflector disc).\nBut this was explained by the producers saying the tech was upgraded from pieces of <PERSON>'s ship that were recovered in the wreckage of the Kelvin encounter and reverse engineered. Yes I know. I just ranted about producer statements. But these statements fit what we see. We now expect to see more advanced tech in a pre TOS Trek than we would have in classic <PERSON> era. Keep this in mind because I will refer to it in a minute.\nI also think we shoul not just write off visual differences. We are dealing with a visual medium here. The look is part of the storytelling. Sure there will be differences. We should expect it. But the best stories are going to explain it not write it off.\nGetting back to it, I believe a case could be made that DSC fits in either timeline but I favor <PERSON>. Yes I say that because of visuals. But let me explain it a bit more.\nLet me first challenge by saying that if we favor a prime placement, we still need to resolve some problems. In fact at least one major one.", "126" ], [ "That's the Klingons. Sure, they've addressed that no one has seen one in a hundred years. That could be a reference to Archer and Enterprise. But remember season 4 of Enterprise.\nFor all its faults, Enterprise finally explained why TOS Klingons look different from TNG and beyond Klingons. They had tried to produce Kilngon Augments. It went wrong and Dr <PERSON> had to use DNA from humans (<PERSON> specifically) to cure the virus. This meant that the entire was subjected to genetic modification and had their appearances altered. But the mod had a shelf life. It would naturally revert in about a hundred years.\nWell we saw that happen during <PERSON>'s era. Yes it was actually in the Motion Picture that we first saw TNG era Klingons. What this means for us is simple. If DSC is set in the prime timeline, the Klingons should not have cranial ridges and use Bat'leth-like weapons. This is 10 years before <PERSON>'s era and nearly a hundred after <PERSON>. The Klingons revised look should have been a revision of TOS era Klingons not modern Klingons.\nBut if this is <PERSON>, we have an interesting solution. DSC is dealing with the unification of the Empire. Why? Well we have more modern looking Klingons, and the entire race seems to follow that look. Given that this would take place after <PERSON> has entered this timeline, that would mean things are different to the point where the mod wore off faster. If no one has seen Klingons in nearly a hundred years, that would mean not many saw the missed Klingons that <PERSON> barely dealt with. Not many witnessed the mod so the expectation when these Klingons are encountered would be no surprise. Anyone who did know about it would just assume it had passed by now.\nGetting back to tech, DSC does not just feature cool visuals. The tech that is depicted cannot be ignored. DSC uses extensive holography aboard Federation starships. In the ptime timeline, this would not have occurred until TNG era and then only on a holodeck. But holography was known much earlier. <PERSON> and his crew encountered the Xyrillians who used such devices in his era. But still the Fed did not implement any such tech. When Columbia was commissioned and launched, it had no holographic tech.\nBut if account for <PERSON> and the fleet upgrades from the remains of the ship, such holographic are more than believable in the DSC era.\nSure we still have to explain the uniforms. But I am working on that.", "837" ] ]

[ 9355, 10328, 2851, 11319, 10200, 4802, 4232, 4262, 10690, 3408, 4705, 5716, 10333, 10194, 388, 1843, 9106, 4203, 8219, 4779, 6703, 7361, 1550, 2332, 10006, 9188, 1331, 1017, 2723, 7043, 10446, 10255, 9256, 1406, 8227, 8688, 442, 9682, 8364, 8880, 8824, 4978, 11132, 8993, 5077, 967, 10883, 11165, 4273, 10858, 6646, 2955, 2824, 6964, 3266, 10576, 6061, 1783, 6262, 5515, 1914, 529, 4233, 5277, 7744, 11070, 9459, 816, 4819, 7757 ]

[ [ "How to interpret a specific feature importance?\nApologies for a very case specific question. I have a dataset of genes, with which I am using machine learning to predict if a gene causes a disease. One of the features I have is a beta value (which is the effect size of the gene's impact on the disease), and I'm not sure how best to interpret and use this feature.\nI condense the beta values from the variant level to the gene level, so a gene is left with multiple beta values like this:\nGene Beta ACE -0.7, 0.1 ,0.6 NOS 0.2, 0.4, 0.5 BRCA -0.1 ,0.1, 0.2\nCurrently I am trying 2 options of selecting a single beta value per gene, one where I select the absolute value per gene (and ignore whether it was a previous negative value) and another where I select the absolute value and return the previous negative numbers back to being negative.", "655" ], [ "I am trying this as for beta values a postive or negative direction indicates the size of the effect a gene has on the disease, so I would think it's important to retain the negative information (as I understand it).\nHowever, I've been advised to use just the absolute values with not retaining negative status, and I'm not sure if there's a way for me to know if one option is better than the other from the machine learning perspective. I am also having a problem in either case where my model values this feature as much more important than any other feature in my dataset. For example gradient boosting gives this an importance of 0.01, the next most important feature is at 0.001.\nSo my question is, how best can I interpret a highly important feature like this? If it is much more important is it actually a bias and is it likely due to my own handling/preprocessing of the feature or is it acceptable that is it just very important? Would it be possible for me to set my model to re-weight the importance of this particular feature? I have a biology background so not sure what is the normal or least biased approach.", "655" ], [ "Feature Selection Statistical Test for Nominal Response Vs Continuous Predictors? (in R)\nI cannot find much information on this, none so-far useful.\nI have a sparse data set with 17K+ columns of continuous gene expressions, an example of a typical column: (3.15, 0, 7.1294, 0, 0, 0, 2300.2, 213.444,...) and each row has an associated nominal response of celltype = 'A', 'B', 'C', 'D', 'E'. These are names, hence nominal, and not ordinal.\nThus, there are 17308 gene expression columns, and a single response column in my dataframe, with 4954 rows/samples.\nI am trying to find the right statistical test to perform a filter-method for feature selection (taking the best 1000 low-correlation p-values obtained through some statistical test). My teacher mentioned Wilcoxon rank sum test, but I dont see how this applies, nor ANOVA. I found the Kruskal-Wallis as the only relatively good test. I do not come from a statistics background, having only taking Mathematical Statistics I in university.\nI use a File Backed Matrix (FBM from bigstatsr package) to assign the p-values in a foreach loop, as follows:\nforeach(i = 1:num_feats, .combine = 'c') %dopar% { dat_total = cbind(df[, i], df$ctype) p_vals[i - 1, 1] <- kruskal.test(df[, i] ~ df$ctype, data = dat_total)$p.value } but this results in about 12000 p_values stacked up at zero... (?)\nI also tried switching df[, i] ~ df$ctype for df$ctype ~ df[, i] but kruskal.test in R asks for response ~ group, regardless, when I do this I get a bimodal distribution of p-values: a few thousand stacked up near 0 (but non are zero) and a few thousand stacked up near 1 (some equal to 1). I read more on this as in 'Section C' found here.\nI'm supposed to just test each column against the response, check for significance, peel off the best 1000, and then generate a feature reduced matrix df_sml that I then feed into elastic net, lasso, linear discriminant analysis and a classification tree.", "655" ], [ "What I did however was pick the best <PHONE_NUMBER> p-values, and pick the top 1000 that had correlation between -0.25 and 0.25 (LDA was failing otherwise).\nANY tips are appreciated, I don't see the point of deriving a test data set for reproduction. This(and several other) articles mentioned Kruskal-Wallis for categorical dependent versus continuous independent variables (but my concern is I am feeding them in 'backwards' to the test in R).\nI dont understand why I would possibly want to factor celltype into a dummy variable, as this is nominal data and not ordinal data, so any explanation regarding that appreciated. If it is okay, why? Doesn't ordinal data imply rank? And if I am treating the dummy variable as factor, how is that different than treating 'A', ..., 'E' as factors?\nThe simplest method you can suggest would be most appreciated, hence my turn to Kruskal-Wallis and not some of the more complicated and involved methods I have seen suggested (I likely wouldn't have the time to implement them).\nedit: I wanted to add a few things: I ran elastic net for alpha = 0.1:0.9 by 0.2 and LASSO, and I am getting a classification accuracy rate around 0.98 for all of these. So unless something is amiss, my models are getting pretty good results, LDA performed just slightly worse (0.96) than Elastic Net (glmnet), the Tree model with pruning (0.76) was garbage lol. And this was using df$ctype ~ df[, i] which is group ~ response, not the desired format by kruskal.test as far as I know. {see ?kruskal.test(formula,...)}\nedit2: I wanted to add, there are like 8K+ columns with 95% entries being zero, but the teacher said to leave them in and do this test instead (this data is for a machine learning course midterm project), which I've read can be what is contributing to the wild number of p-values stacking up at or near 1. I originally stripped these columns from the dataframe.", "458" ], [ "How many ways are there to check model overfitting?\nI am running xgboost on a regression classification problem where the model is predicting a score of how likely a gene is to cause a disease from 0-1.\nI try to avoid overfitting in all the ways I can think of and the mean output of nested cross-validation is r2 0.88, I'm not sure if I can trust this or if there are other ways I can see if this is overfitting. The output r2 on just training and testing non-nested is: Train r2: 0.971 Test r2: 0.868.\nSo far I: - Remove features with a correlation >0.9 and remove any features with >50% missing data (this is hard to strengthen, a lot of genetic features simply have missing data for a lot of under studied genes in biology) - Have no imputation to avoid imputation bias, and since xgboost accepts missing data. - Scale features with MinMaxScaler() in scikit-learn - recommended as a good starting point and most features don't have a normal distribution - Compare 2 feature selection methods (one using features xgboost deems important from SHAP values and one using Boruta, both give 0.87-0.88 r2 on average of the 10 nested CV k-folds and only remove 3-4 out of 57 features) - Use nested kfold cross validation with 10 kfolds\nThe only other area I'm aware of that I haven't really explored is projection techniques. I am not sure which method would be best for this (my features are all numeric but mixed continuous or discrete data types) such as between UMAP, PCA or partial least squares.\nAre there any other ways I can investigate overfitting? I have a biology background so any resources on this would be useful and any help appreciated.\nI have also more manually removed some minority example genes before training (e.g.", "392" ], [ "removed training genes with a 0.9 score which make up only about 1/8 of the training dataset) to give the trained model to predict and view how the model generalises to this 'new' hard to predict genes - gives them a 0.6-0.7 score when they are actually 0.9:\n``` y_pred =<PHONE_NUMBER>, 0.709764, <PHONE_NUMBER>]\ny_true = [0.9, 0.9, 0.9]\nr2_score(y_true, y_pred) #outputs 0.0\n```\n10-fold nested cv r2 results per fold: 'test_r2': array([0.8484691 , <PHONE_NUMBER>, <PHONE_NUMBER>, <PHONE_NUMBER>, <PHONE_NUMBER>, <PHONE_NUMBER>, <PHONE_NUMBER>, <PHONE_NUMBER> , <PHONE_NUMBER>, <PHONE_NUMBER>]\nEdit:\nA few other things I've tried:\n* I think I've misused classification here (and removed tag accordingly), I use regression models and I don't have labels and only continuous scores so I don't get true positives, false positives etc. to be able to do ROC. I'm not sure what other metrics are good or better than R2 for regression that I can use.\n* I have tried applying imputation to compare other models (random forest, SVM, and logistic rgeression with elasticnet or lasso), all models perform notably lower than gradient boosting (0.59 average nested r2 is the highest with random forest) - but I was originally concerned with biased data from imputation, is imputation worth doing to counteract overfitting?\n* I use GridSearch in scikit-learn for all my models with nested cross-validation, I should have included this information originally as I have been trying to always do this.\nI have a biology background, so not sure about best practices for machine learning, but from this I'm suspecting random forest is better and I should be trying to do a better parameter tuning than I currently do for it, and trusting that model's result on nested CV. Is this the best approach?\nAlso not sure if how I tune my random forest is reasonable, currently I use: rfr = RandomForestRegressor(random_state=seed) rfr_params={'n_estimators':[100, 500, 1000], 'min_samples_split': [50, 100], 'min_samples_leaf': [50, 100],}", "392" ], [ "Assign cluster members using log-likelihood distance metric in python\nWant to clarify that I am pretty new to this area - help would be appreciated :)\nI have 100 clusters, each with a mean and standard deviation value. These clusters are predefined using the SPSS software package, by using the 2-step cluster method. Therefore, the optimisation of these cluster distributions to fit the data has already been done.\nFor new (unseen) data, we want to assign cluster membership by selecting the maximum log-likelihood cluster, for any given set of coordinates X.", "506" ], [ "To do this, I have written my own code for comparison with what was output by SPSS using the same method: https://www.norusis.com/pdf/SPC_v19.pdf\nUsing data that has been correctly labelled by SPSS, about 42% of the clusters are correctly labelled by minimising the RMSE to the cluster mean (which is not what SPSS does), and less than 20% of the clusters are labelled correctly by my code when assigning the maximum log-likelihood cluster (which is what SPPSS reports to do).\nI know that the maximum log-likelihood cluster should be the correct cluster ( https://www.norusis.com/pdf/SPC_v19.pdf ), but there is only a 20% success rate from this code when compared to the correct cluster labels from SPSS. What am I doing wrong?\nHere is the code below.\n``` import pandas as pd import numpy as np from sklearn.metrics import mean_squared_error import math from scipy import stats\nimporta raw files\nclusters_df = pd.read_csv('ClusterCoordinates.csv') # clusters are in order of cluster numbers enabling us to use index for identification clusters_df = clusters_df.drop(columns=['Cluster']) print(clusters_df.shape) clusters = clusters_df.to_numpy()\nframes_df_raw = pd.read_csv('FrameCoordinates.csv') frames_df = frames_df_raw.drop(columns=['frame','replica','voltage','system','ff','cluster']) print(frames_df.shape) frames = frames_df.to_numpy()\nclusters_sd_df = pd.read_csv('ClusterCoordinates_SD.csv') clusters_sd_df = clusters_sd_df.drop(columns=['Cluster']) print(clusters_sd_df.shape) clusters_sd = clusters_sd_df.to_numpy()\nrmseCalc = [] llCalc = [] assignedCluster_RMSE = [] assignedCluster_LL = []\ncreate tables with RMSE and LL values\nfor frame in frames: for cluster, cluster_sd in zip(clusters, clusters_sd): # we compare cluster assignment using minimum RMSE vs maximum log likelihood methods. rmseCalc.append(math.sqrt(mean_squared_error(np.array(cluster),np.array(frame)))) llCalc.append(-np.sum(stats.norm.logpdf(frame, loc=cluster, scale=cluster_sd))) rmseCalc=np.array(rmseCalc) llCalc=np.array(llCalc) llCalc=np.nan_to_num(llCalc) minRMSE = np.where(rmseCalc==rmseCalc.min()) maxLL = np.where(llCalc==llCalc.min()) print(maxLL[0][0]+1) assignedCluster_RMSE.append(minRMSE[0][0]+1) assignedCluster_LL.append(maxLL[0][0]+1) rmseCalc=[] llCalc=[]\nframes_df_raw['predCluster_RMSE'] = np.array(assignedCluster_RMSE) frames_df_raw['predCluster_LL'] = np.array(assignedCluster_LL) frames_df_raw.to_csv('frames_clustered.csv')\n```\nI was expecting the cluster labels assigned by the code to match those already assigned by SPSS, since the methods used are intended to be the same.", "506" ], [ "How to create a prediction interval with the fact that the residuals follow a specific distribution (in python)\nI am looking at a software development pipeline where I am predicting the lead time of different products flowing through the pipeline.\nAfter applying a boxcox transformation on the lead time (target variable) and creating a XGBoost regressor model I can see that the residuals follow a t-locationScale distribution.\nSo now I looked at this guide which describes a method to create a prediction interval for any regression model assuming that the residuals are normally distributed. https://qucit.com/a-simple-technique-to-estimate-prediction-intervals-for-any-regression-model_en/\nBut I tried to tweak it to my distribution.\nSo a t-locationScale distribution has a $\\sigma$, $\\mu$ and $\\nu$ parameter. The variance is only defined for $\\nu>2$.", "509" ], [ "My specific distribution has $\\nu = 2.56$ and $\\mu = 0.04$, $\\sigma = 0.97$ So I could take the 95% interval of this distribution and say that for any $\\hat{y}$, the prediction interval is the 95% interval of the residual distribution.\nBut I want to take into consideration that the prediction interval should change with different inputs. I created a regressor model, which I trained and then made predictions using the validation set. I then took the square of the error and trained an additional error model on this data. Such that the error model could predict the variance of the residuals distribution.\nxgb = XGBoostRegressor()\nxgb.fit(X_train,y_train)\ny_hat = xgb.predict(X_val)\nval_error = (y_hat-y_val)**2\nxgb_error = XGBoostRegressor()\nxgb_error.fit(X_val, val_error)\nvariance_hat_residuals = xgb_error.predict(X_test)\nThe relationship between variance and $\\sigma$ and $\\nu$ for a t-locationScale distribution is\nvar = $\\sigma^2 *\\frac{\\nu}{\\nu-2}$\nNow here is where I make an assumption which I am not sure makes sense.\nI assume that the degrees of freedom $\\nu$ is the same as for all residuals, $\\nu = 2.56$ and then I solve for $\\sigma$ through the following.\n$\\hat{\\sigma} = \\sqrt{\\frac{\\hat{var}*(\\nu-2)}{\\nu}}$\nAnd estimate the lower and upper quantiles from this distribution.\nresidual_distribution_lower_quantile = scipy.stats.t.ppf(q = 0.025, df = 2.56, scale = sigma)\nresidual_distribution_upper_quantile = scipy.stats.t.ppf(q = 0.0975, df = 2.56, scale = sigma)\nI then predict the lead time $\\hat{y}$ and say that the mean of the distribution is $\\hat{y}$\npred = xgb.prediction(X_test)\nlower_interval = pred + residual_distribution_lower_quantile\nupper_interval = pred + residual_distribution_upper_quantile\nDoes it make sense to make the claim of $\\nu$ is static? My score for the prediction interval is now $81\\%$ since I am clearly simplifying the problem.\nAny suggestions for improving my method?", "509" ], [ "Despite the downvote, the question is clear, and a common one I'm sure most stumble across after doing machine learning work for some time.\nThe goal was to make a stronger predictive model from multiple trained models.\nQuote from my question:\nis it possible to aggregate these 30 fitted models into a single model?\nAnswer: yes but there's no good functionality that allows you to do this in sklearn.\nVerbose answer:\nImagine you have 30 CSV files that contain 15,000 0 class and 15,000 1 class samples. In other words, an equally balanced number of binary responses (no class imbalance). I generated these files myself because 1) the size of the data I'm working with is too big to fit into memory (point #1 of my original question) and 2) contains 97% class 0 and 3% class 1 (large class imbalance). My goal is to see if it's even possible to distinguish between a 0 or a 1 if the class imbalance issue was removed from the equation. If there were distinguishing features found, I'd want to know what those features were.\nTo generate each batch, I grabbed 15,000 1 responses, and randomly sampled from the 97% 15,000 more samples, joined into one dataset (30,000 samples total), then shuffled them at random.\nI then went through each batch and trained an XGBClassifier() using optimal parameters found from GridSearchCV() for each. I then saved the model to disk (using Python's pickle capabilities).\nAt this point, you have 30 saved models.\n/models/ directory looks like this:\n['model_0.pkl', 'model_1.pkl', 'model_10.pkl', 'model_11.pkl', 'model_12.pkl',\n'model_13.pkl', 'model_14.pkl', 'model_15.pkl', 'model_16.pkl', 'model_17.pkl',\n'model_18.pkl', 'model_19.pkl', 'model_2.pkl', 'model_20.pkl', 'model_21.pkl',\n'model_22.pkl', 'model_23.pkl', 'model_24.pkl', 'model_25.pkl', 'model_26.pkl',\n'model_27.pkl', 'model_28.pkl', 'model_29.pkl', 'model_3.pkl', 'model_4.pkl',\n'model_5.pkl', 'model_6.pkl', 'model_7.pkl', 'model_8.pkl', 'model_9.pkl']\nAgain, going back to the original question - is it possible to aggregate these into a single model? I wrote a pretty basic python function for this.\ndef xgb_predictions(X):\n''' returns predictions from 30 saved models '''\npredictions = {}\nfor pkl_file in os.listdir('./models/'):\nfile_num = int(re.search(r'\\d+', pkl_file).group())\nxgb = pickle.load(open(os.path.join('models', pkl_file), mode='rb'))\ny_pred = xgb.predict(X)\npredictions[file_num] = y_pred\nnew_df = pd.DataFrame(predictions)\nnew_df = new_df[sorted(new_df.columns)]\nreturn new_df\nIt iterates through each file in a directory of saved models and loads them one at a time casting its own \"vote\" so-to-speak.", "650" ], [ "The end result is a new dataframe of predictions.\nSince this new dataset is smaller (X.shape x 30), it will fit into memory. I iterate through each batch file calling xgb_predictions(X), getting a dataframe of predictions, add the y column to the dataframe, and append it to a new file. I then read the full dataset of predictions and create a \"level 2\" model instance where X is the prediction data and y is still y.\nSo to recap, the concept is, for binary classification, create equally balanced class datasets, train a model on each, run through each dataset and let each trained model cast a prediction. This collection of predictions is, in a way, a transformed version of your original dataset. You build another model to try and predict y given the predictions dataset. Train it all in memory so you end up with a single model. Any time you want to predict, you take your dataset, transform it into predictions, then use your level 2 trained model to cast the final prediction.", "57" ], [ "How to add bias consideration into logistic regression code?\nI am a complete beginner in coding and machine learning, and I've been tasked with learning what's under the hood of logistic regression (so I have pieced together the python code below) but I've been asked to figure out how to add bias into this code. I'm completely stuck on at what point it would need to be added into, I think at the point I am defining the hypothesis function - but if anyone would be able to point me in the right direction to figure this out I would really appreciate it.\nIf it helps, this logistic regression is being used to classify if a tumour is benign of malignant with the wisconsin breast cancer dataset (https://www.kaggle.com/uciml/breast-cancer-wisconsin-data)\nX_train,X_test,Y_train,Y_test = train_test_split(X,Y,test_size=0.3)\nX = data[\"diagnosis\"].map(lambda x: float(x))\nX = data[['texture_mean','perimeter_mean','smoothness_mean','compactness_mean','symmetry_mean', 'diagnosis']]\nX = np.array(X)\nX = min_max_scaler.fit_transform(X)\nY = data[\"diagnosis\"].map(lambda x: float(x))\nY = np.array(Y)\ndef Sigmoid(z):\nif z < 0:\nreturn 1 - 1/(1 + math.exp(z))\nelse:\nreturn 1/(1 + math.exp(-z))\ndef Hypothesis(theta, x):\nz = 0\nfor i in range(len(theta)):\nz += x[i]*theta[i]\nreturn Sigmoid(z)enter preformatted text here\ndef Cost_Function(X,Y,theta,m):\nsumOfErrors = 0\nfor i in range(m):\nxi = X[i]\nhi = Hypothesis(theta,xi)\nerror = Y[i] * math.log(hi if hi >0 else 1)\nif Y[i] == 1:\nerror = Y[i] * math.log(hi if hi >0 else 1)\nelif Y[i] == 0:\nerror = (1-Y[i]) * math.log(1-hi if 1-hi >0 else 1)\nsumOfErrors += error\nconst = -1/m\nJ = const * sumOfErrors\nprint ('cost is: ', J )\nreturn J\ndef Cost_Function_Derivative(X,Y,theta,j,m,alpha):\nsumErrors = 0\nfor i in range(m):\nxi = X[i]\nxij = xi[j]\nhi = Hypothesis(theta,X[i])\nerror = (hi - Y[i])*xij\nsumErrors += error\nm = len(Y)\nconstant = float(alpha)/float(m)\nJ = constant * sumErrors\nreturn J\ndef Gradient_Descent(X,Y,theta,m,alpha):\nnew_theta = []\nconstant = alpha/m\nfor j in range(len(theta)):\nCFDerivative = Cost_Function_Derivative(X,Y,theta,j,m,alpha)\nnew_theta_value = theta[j] - CFDerivative\nnew_theta.append(new_theta_value)\nreturn new_theta\ninitial_theta = [0,1]\nalpha = 0.01\niterations = 1000\nLogistic_Regression(X,Y,alpha,initial_theta,iterations)", "422" ], [ "How should one interpret heritability? Is it related to $R^2$?\nFrom Wikipedia:\nHeritability estimates are often misinterpreted if it is not understood that they refer to the proportion of variation between individuals on a trait that is due to genetic factors. It does not indicate the degree of genetic influence on the development of a trait of an individual. For example, it is incorrect to say that since the heritability of personality traits is about .6, that means that 60% of your personality is inherited from your parents and 40% comes from the environment.\nSo what is the plain english interpretation of heritability?\nIs it supposed to be the genetics version of $R^2$? If so, please explain it to me anyway because I forgot my statistics.\nI found this so from what I understand, one might say:\nIf height is estimated to be 80% heritable, and if we get 10 people, get their heights and then compute the variance, we say that around 80% of that variance is likely due to genetic factors while the remaining 20% is due to other things.\nSuch interpretation of heritability seems to work for non-categorical traits. What about categorical or binary traits?\nHair and eye colour is categorical (I think?).", "882" ], [ "So what, we assign a number for each colour and then compute the variance?\nADHD is binary (I think?). Do we assign 0 for not having and 1 for having then compute variance?\nI seem to recall regressing binary or categorical variables needs some kind of adjustments and hence interpretations of estimates (such as intercepts or slopes) may be different.\nAlso, the book linked above says\nheritability represents the degree to which the variance in a trait is attributable to genetics in the population on average\nCombining that with the Wiki paragraph above, I don't think someone saying\nEye colour is around 98% heritable. I have brown eyes. Therefore, around 98% of the reason why I have brown eyes is genetics.\nis far off from saying\nIf we have a million people who near-identically flip a million near-identical coins a hundred times, and we compute the average of the coin flips that turn out to be heads to be 58.6, then the probability that you will flip heads when you near-identically flip this near-identical coin is around 58.6%.\nIs it? (Of course 'near', 'around', etc are not always used similarly...lol)\nSo yeah, technically the 60/40 interpretation in the Wiki example is technically wrong but practically it's around 60% $\\pm$ some standard deviation?", "655" ] ]

[ 6348, 10174, 10611, 7177, 2118, 5487, 11314, 4703, 5242, 926, 1053, 2800, 10387, 6172, 1511, 4466, 9826, 10251, 9575, 11423, 5498, 5484, 8422, 8090, 2866, 1122, 1091, 3428, 410, 7248, 8307, 5084, 1453, 1220, 8807, 7617, 5306, 10549, 5001, 9324, 3892, 1816, 9486, 7041, 2494, 5728, 8863, 1669, 8206, 7856, 306, 5050, 10457, 8721, 2904, 4847, 5071, 4582, 1089, 4192, 9787, 4280, 6488, 9467, 9851, 64, 5303, 1558, 4620, 801 ]

[ [ "When I found out that my daughter-in-law’s favorite classic game was ‘Clue’, I realized that I’d never researched any ‘gateway’ game for fans of that game. I’d seen a lot of ‘How to Host a Murder’ games in some game stores, but never anything that caught my attention. It didn’t take much research to find that two games kept coming up – ‘Sleuth’ and ‘Mystery at the Abbey’. A closer inspection led me to believe that ‘Mystery at the Abbey’ was just what the doctor ordered.\nComponents: Three words…’Days of Wonder’.\nThe gameboard features the layout of the abbey, and it’s a gorgeously thematic layout. The room names are written in Latin (the cheat sheets label them in Latin and English). The placement outlines for the different decks of cards are at the corners of the board so that the cards don’t impede the game.\nThe pawns are miniature monk statuettes of different colors. The cards are artfully simple, the cheat sheets are colorful, helpful, and well laid out, and even the suspect sheets are nicely designed (though I wish that more of them were included). All in all, the quality of components here is exemplary.\nRules: The rule book is in a very familiar layout, so anyone owning Ticket to Ride or Colosseum should be used to the format. It’s a good thing, too. Your first game or two might find you in the rule book quite a bit. It’s not that the rules are complex – they’re really not. But a newbie to this game will probably refer back for clarifying what constitutes a ‘legal’ question, when to play a particular card, and what happens in certain rooms. (The cheat sheets can be a valuable source of this information once people get into the habit of checking them). Once you get the basic hang of it, it’s pretty easy. We had four newbies (and no one who ever played), and were able to get the hang of the game pretty quickly.\nTheme: One of the 24 monks has killed brother <PERSON>. Three to six players act as sleuths to try and find the killer by asking questions of the monks and receiving clues in a variety of ways. On one level, the game is very thematic.", "504" ], [ "The old-style fonts used on the cards and board, the rustic looking floor plan, the miniature ‘mass bell’ are all designed to enhance the mood. But there’s knowing wink (with tongue planted firmly in cheek) with cards that require players to sing ‘Frere Jacques’ in rounds or deliver questions in a chant. You’ll love the theme, but you’ll never forget that it’s just a game (and a fun one).\nGameplay: Each hour in the game, a mass card is turned and mass is held where all the monks gather in the Chapel. After mass, they have four moves (three moves if there are six players) to roam around the building searching for clues. Each move consists of them traveling to one or two rooms (three rooms for six players). When their move ends with them sharing a room with another player, they can ask that player a question to help narrow down the suspects. That person can take a vow of silence or answer the question. If he answers, he is allowed to ask a question in return.\nSeveral rooms entitle the player a benefit, such as choosing a card from another player of gaining a card that can grant them information or a free turn or some other benefit. This is in addition to the ability to question another monk. The Library can give you access to a wealth of information, but you can only go there once (and only when you have less cards than anyone else. ‘Penance’ can also be declared on someone who misbehaves, such as forgetting to move the mass bell or not sing ‘Frere Jacques’.\nOne special room is the Chapterhall. Players must travel to this room if they wish to make a revelation (release positive information about the identity of the killer, such as ‘He had a beard’ or ‘He was a Franciscan monk) or an accusation (naming a specific suspect as the killer). It is room that is farthest away from the chapel.\nAfter four turns, the bell is rung and players return to the chapel. Each player passes a certain number of his cards to the player on their left. An event card is drawn and acted upon. The next mass card is turned over, and a new round begins. The game ends when someone makes a correct accusation (the card depicting the killer is not in anyone’s hand).", "937" ], [ "I’ve owned this beauty for a few months, but as most of my gaming is two player, it took a while to get this to the table. Last week, though, we got a group of four together and I suggested Shogun, as the group was made up of wargamers, euro gamers, and RPGers.\nBy way of brief background, I am primarily a wargamer with a deep interest in history and secondarily an Ameritrash gamer with an affinity for fantasy and sci-fi themes.\nComponents\nThis game is really attractive, which is one reason I bought it in the first place. The map is really beautiful, and well mounted. The cards are nice (though a bit small) and have a nice finish. The wooden blocks are cool, and look great piled up on the enemy’s border, ready to heave across at H-Hour. The artwork is solid throughout and very evocative of the theme.\nThe cube tower is brilliant. I’ve read complaints about trying to justify its somewhat random outcomes, but I had no problem here. So I attack with 4 armies and 5 pop out. So what? Maybe my success drew more to my cause.\nIn any case, I didn’t worry about justifying this game’s particular randomizing mechanic, I just appreciated its originality and ingenuity.\nObject\nShogun is a multiplayer game of building and conflict in feudal Japan. The object is, over the course of two years, to gather more victory points than your opponents. Victory points are accrued twice during the game, at the end of each year. During the scoring phase, you get a VP for:\nEach controlled province\nEach building\n3 VP: Most Castles in a region (a region is a group of 9 color-matched provinces)\n2 VP: Most Temples in a region\n1 VP: Most Theaters in a region\nTurn Phase\nEssentially, there are 3 turns (spring, summer, fall) followed by a scoring phase (winter). Then three more turns, followed by a second scoring phase. After that, high score (most VP’s) wins.\nThe turn sequence is:\nLay out action cards .", "366" ], [ "This means determine in which order that turns ten ‘actions’ will occur. The ten actions are the same each turn, and are generally one of four types: 1) spending treasure chests (hereafter “gold”) to raise armies 2) spending gold to build buildings, 3) move and attack, 4) raise taxes by gathering gold or rice from a province. The ten actions are very specific (for example, one allows a player to raise 5 armies for 3 gold, while another allows a levy of 3 armies for 2 gold). The first five actions are face up, so you know what’s coming, the last five are face down, and revealed one at a time as the face up actions are executed.\nLay out special cards . There are five of these, that give the player some small advantage for the turn, like raising an extra army or gold, or adding one army to attack or defense. They are randomly place on a turn order chart. So if the ‘add one gold to your taxes’ advantage is placed on turn order #3, and you select that advantage, you are also choosing to go third in each phase of the turn.\nPlan Individual actions . Here is where most of the game time occurs, and this is the source of one of my main complaints with this game. Here the players assign one of the game’s ten standard actions to one of their provinces. For example, by placing a province card, face down, on one’s player mat with the ‘pay three gold and raise 5 armies’ action, when that phase comes up, the specified action takes place in that province…and only that province. No province gets two actions in a phase, and no action can take place in more than one province. Forget out raising an army and attacking with it in one turn.\nYou'll spend a lot of time staring at this\nPlayers also bid for turn order in this phase, by committing 0 to 4 gold. Once revealed, the highest bidder selects the advantage and turn position they want (i.e. ‘special card’ mechanic described above).\nDetermine events .\nA random event card is turned over that has a global effect on the turn, like not allowing combat in a temple space, or capping the amount of rice gathered by taxes.\nDetermine Turn Order .\nHere players choose there special card (i.e. advantage for the turn) along with their turn order, in order of highest bid placed in the ‘Plan Individual Actions’ phase above.\nA close up of three of the five 'special cards' on the turn order track\nCarry out actions .", "629" ], [ "These days, it’s not uncommon to find card games that disguise themselves as something much more. They push the envelope and redefine how complex, strategic, and/or thematic a card game can be. Guillotine is the antithesis to these, a basic card game that makes no pretensions. Two decks of cards, a toy (non-working) head-chopper, and that’s all it needs to be a cut above your average filler.\nComponents: See above. The two decks of cards – the action deck and nobles deck - are colorfully designed (with tongue firmly in cheek) on decent quality stock and nicely coated. (Despite all the execution, there is no ‘die’ to roll). Not much more to say on that!\nTheme/Object of the game – You are one of the executioners during the French Revolution just trying to make a name for yourself by executing the highest ranking nobles (based on point value) in line. Of course, other executioners are also out for the fame and fortune you desire. Your job is simple: behead the first noble in line at the end of your turn. But playing the right action card at the right time can make all the difference in the world. The person with the most points at the end of three days of executions is the winner.\nRules: Dirt Simple. You start out with five action cards in your hand and 12 nobles in line to lose their head during day one of executions. You have the option of playing an action card at the beginning of your turn.", "237" ], [ "If so, you execute (pun intended) the action immediately. Whether you’ve played an action card or not, you then must behead the first noble in line, then take another action card from the deck. When there are no more nobles in line, lay out 12 more for the next day. The game is over after three days of executions. Any exceptions to these rules are printed on the cards themselves.\nGameplay: I’m not just sticking my neck out when I say that this is where the game shines. The action cards in your hand allow you to do a variety of things – rearrange the line (or prevent people from rearranging it), add or subtract nobles to the line, assess penalty points to other players, reverse the order of nobles, etc. While this may not be the most strategically challenging exercise, it is unpredictable and fun. Sure, there’s a hefty amount of luck involved, but having a few decisions on which is the best play at any one time is just enough to give you bragging rights when you win.\nGood Stuff – This is a card game that plays in about 15-20 minutes and is a great filler game. Selling for about $15, it’s also a pretty good deal. You can always play fewer hands (days) than prescribe, or reformat the game to make the game longer (but remember, there are only so many nobles cards). Having no small parts also makes this very portable.\nBad Stuff – The game can wear out its’ welcome if it’s played too much, and the theme might be a turn-off for those who are easily offended.\nFinal Words. Guillotine is a wonderful find – a multi-player filler game with a warped sense of humor and an air of unpredictably. It’s not very deep nor is it grandiose, but is a lot of fun. I can see myself picking up this game and keeping it in the car to play at coffee shops or wherever the opportunity presents itself.", "237" ], [ "All of my reviews aim to offer a brief overview that allows people to get a good feel for what the game may offer them. I feel that other reviews can be sought if detailed game mechanics is what you are after.\nSummary\nGame Type - Board Game (Experience Game)\nPlay Time : 2-4 hours (Under 3 once familiar)\nNumber of Players: 2-14 (Recommend 3-6 unless used in a special event)\nMechanics - Roll & Move, Quest Game, Character Development Game, Dice Rolling\nDifficulty - Moderate (Learn in 1 hour)\nComponents - Very Good (See Components section for more detail)\nI’ll state up front that I have heard many things about Talisman but had never played it before the 4th Edition. I am happy with this as it will lend my review a perspective that is free of nostalgia and baggage.\nWelcome to Talisman in its 4th incarnation. The story goes something like this - The last ruler of Talisman, a mighty wizard, decided on his deathbed, to set a great challenge to any would-be successor. Anyone who could claim his magical crown, forged in the Valley of Fire, would become the new ruler of Talisman. With his last ounce of strength he placed the crown in the most perilous region imaginable and protected it with powerful spells and guardians. Now adventurers from near and far take on the quest to claim the crown and install themselves as the new ruler.\nOk so I used some poetic license, but you get the idea. Talisman tries to appeal to the 12 year old in all of us, offering a fantasy world beset with challenges and potential victories. It plays like an RPG without the acting and it is a ‘level up’ game, where you must build up the skills of your character in order to face the many perilous challenges that await you. By now you should know if you wish to read on.\nThe game offers a choice of 14 different characters and they cover almost all the classic character classes (although <PERSON> and Troll are unusual inclusions). Each character has a unique mix of special abilities, although some abilities are similar in nature. What each character has in common are their base attributes. These include Strength, Craft, Life and Alignment. Each character starts in a different location and a character card outlines all of the above information.", "857" ], [ "The card also serves to act as an organizational tool of sorts as each player must place small gem tokens (representing base skill values) at various places alongside their character card.\nThe board consists of 48 spaces and they create 3 distinct rectangular regions. I use the term ‘spaces’ because Talisman is a classic ‘roll and move’ game. I was surprised when I initially made this discovery and I was ready to dislike the game. The question I remember asking myself was, “How can a ‘roll and move’ game appeal to anyone over 12 and what is it doing in the year 2007?” But please read on.\nEach space has its own text, with the majority of spaces instructing the player who lands there to draw 1 or 2 cards from the Adventure Deck (more on these later). Other spaces may have more specific instructions that require the roll of a dice to determine the outcome, which will be good, bad or no change. These features remind us that the original Talisman does dates back to 1983. What’s surprising is how quickly the game draws you in and helps you accept these mechanics for what they are.\nOuter Region – All characters start in a location in this region and much of the game is played out here as it contains many a rolling hill, field, plain or wood. These spaces are almost entirely ‘draw card’ options and it is the events found in the Adventure Deck that drive the game and allow players to ‘skill up’. Players will usually only leave the Outer Region when they believe their characters are sufficiently developed to take on the challenges of the Middle and Inner Region. The Middle Region is cut off from the Outer Region by the Sword River and can only be crossed by Bridge or Raft. The Bridge is guarded by the Sentinel who must be defeated in order to pass. This is no easy feat so often the second option is taken, crossing by Raft. A raft can be built if a player possesses an axe and ends their turn in a wood or forest space. There are one or two other ways to cross but I’ll let you discover those for yourself.\nMiddle Region – This region also has a number of ‘Draw Card Spaces’ but it is generally more dangerous as enemies may gain additional strength, due to their location, and the desert will result in an automatic loss of life (unless you carry a water bottle). This region however is the home of the Temple.", "937" ], [ "Nexus Ops has long had a good reputation with a broad range of BGGers. I hesitated to buy it for a long time, as I lean decidedly toward wargames and heavy Ameritrash games. Finally, however, I broke down and picked up Nexus Ops based on several comments that it may soon be unavailable, not to mention its low price ($20 plus shipping).\nI’ve already played the game several times, a fact which is in itself amazing to me. To play a game four or five times in the first week of owning it is impossible for my usual game. For many wargames I’d still be punching and clipping units, and reading rules. Not so with this game. The rules are incredibly straight forward and easy to understand.\nNow, if you are a wargamer you might think this leads to a shallow or unsatisfying game experience. But, unusually, this game provides some decent tactical options with a bare minimum of rules.\nThere are already many very good reviews on this game that describe the basic mechanics, so I’ll highlight the mechanics that, for me, make this a really fun game.\nUnits:\nFirst, unlike most historical games, you can choose which units to buy each turn. Will you attempt to swarm the enemy with cheap 2 rubium (i.e. ‘dollar’) humans and 3 rubium Fungoids and Crystallines? Or will you spend 8 rubium on a lava leaper or 12 on a dragon? On most turns you’ll earn between 8 and 14 rubium, so choose wisely.\nSecond, the units themselves offer just enough uniqueness to make the choice interesting.\nHumans\nHumans cost 2 and can mine (some spaces have mines on them that generate either 1, 2, or 3 rubium per turn….assuming someone is there to mine them. Humans only hit on a 6 (on a six sided die) so they are either miners or cannon-fodder.\nFungoids\nFungoids cost three, hit on a 5+, and can also mine. Additionally, they are stronger in fungal terrain and weaker on crystal terrain.\nCrystallines\nCrystallines are similar to Fungoids with a cost of 3, a 5+ hit number, ability to mine, and a terrain based strength and weakness (the inverse of the Fungoids, i.e.", "366" ], [ "strong on crystal, weak on fungus).\nRock Strider\nThe Rock Strider is probably my favorite, as it costs 6, hits on a 4+, and, critically, can move two spaces when moving to, or through, Rock Plains. The additional mobility is a huge benefit where most units can only move one per turn (and because new purchases always start back at the ‘home base’ and have to march to the front).\nLava Leaper\nThe Lava Leaper, at a cost of 8 and a hit number of 3+ has a few special abilities too. It can move two when leaving a magma space (but there are only three of those) and on a 5+ attack role it can decide which enemy unit to destroy.\nRubium Dragon\nThe big dog is the rubium dragon. At a cost of 12, it can hit on a 2+, can breath plasma to an adjacent space (hitting on a 4+) and can land anywhere if it takes off from the monolith.\nThe beauty of the system is that all the special rules are included on a handy chart, so there is nothing to memorize. The differences are small, but become significant in such a finely balanced game.\nMission cards:\nThe other game mechanic I enjoy, and which is really the heart of the game, is the secret mission cards. Each turn you draw a card which lists some objective. On your turn (usually after winning a battle) you can play one or more mission cards whose conditions you have met. Some examples include winning a battle on a certain terrain type, destroying a certain unit type in battle, or entering battle with a certain unit.\nThe nice thing about the secret mission cards is they keep your opponent guessing. Often, its hard to know where to defend. Generally you want to keep your mines out of enemy hands, but in many cases the rock plains right next door, and defended by a lone human, might just be the perfect target for someone who has a card that allows them to gain 2 VP’s just by winning a battle on a rock plains space.\nEnergize cards:\nFinally, the last mechanic I find particularly interesting is the energize cards. I understand from others on BGG that this is a very ‘euro’ mechanic. In any case, it works. You earn an energize card when you lose a battle, or two if you control the monolith.", "237" ], [ "This article is taken from the Maven Games blog.\nTerra Mystica is one of my top ten games of all time. I’ve played it and played it over the years. When I heard that they were retheming Terra Mystica in space (Gaia Project), I was very interested, but also apprehensive. Would it just be a straight retheme or would there be significant differences? Could they really improve on what I perceived to be a near-perfect Euro? Would there be an inevitable disappointment that either it didn’t really add anything significant or was actually worse because they made changes that I wasn’t keen on?\nWell, following its release at Essen, Gaia Project has been played by our gaming group at almost every opportunity. Terra Mystica is a group favourite, so everyone wants to try it. First up, let me tell you: they did it. I don’t know how they managed it, but it’s better. It looks like you can improve on perfection after all. So today I’d like to talk about the differences between Terra Mystica and Gaia Project and why I think Gaia Project is a better game. Is it good enough to purchase if you already own Terra Mystica though? Let’s have a look…\nThe first thing that strikes you about Gaia Project is that all the wooden components of Terra Mystica seem to have turned to plastic. I guess it fits the sci-fi theme more, and the building models are good. There’s just something about wood that says quality though. It doesn’t bother me personally; the plastic isn’t cheap plastic, but it’s still plastic and I know some people are always going to prefer wood.\nWhen you start playing Gaia Project, it does feel very similar to Terra Mystica. The faction boards are laid out in a very similar way. The buildings are essentially the same (they’ve just been renamed) and the upgrade paths between them are the same as well. However, as soon as you look at the main board, you realise something that makes a pretty big difference. All the planets you’re trying to terraform are separated by lots of… space.", "304" ], [ "The kind of space that requires a spaceship to traverse!\nThe board is modular, which is great by the way – it means that the layout of all the planets is radically different each time you play. However, the vast majority of planets aren’t adjacent to other planets so you can’t do a couple of easy terraforming actions at the start like you can in Terra Mystica. In order to reach nearby planets you have to increase your navigation range (think shipping), which is pretty crucial. To help out with this though, there is a new resource known as the quantum intelligence cube (QIC). QICs can been used for several things, but spending one allows you to temporarily increase your navigation range by 2.\nThe other resources are broadly the same (although ‘workers’ are now ‘ore’), but the priests from Terra Mystica have gone. They have been replaced by ‘knowledge’. You have to spend knowledge, as an action, to advance on one of the tech tracks. Tech tracks? Yes, and this is where the biggest difference between Terra Mystica and Gaia Project really comes into play. The spade (terraforming) and shipping (navigation) tracks on each of the faction boards in Terra Mystica have been moved onto a central tech board for Gaia Project. This tech board also contains tracks that provide several types of resource income (knowledge, money, power, QICs, etc), but also has an eponymous Gaia Project track. More on that in a bit.\nThe favour tiles from Terra Mystica have now been integrated into the tech board. The locations are variable, but most of the tech (favour) tiles are now linked with one of the tech tracks. Whenever you gain a tech tile, by building the appropriate building, you advance on the matching tech track. It’s absolutely great! Since the allocation of the tech tiles varies each game, you have some tricky decisions to make. Taking one tech tile might be more beneficial to you right now, but the tech track it’s linked to might not fit with your current strategy. So maybe you would be better taking a different one? It adds another layer of strategy and provides for a lot of variability.\nSo what is a Gaia Project then? Well, there’s one kind of planet (the Gaia planet), which anyone can build on. It doesn’t need terraforming, you just have to spend a QIC. However, there are also these purple planets that no one can build on (initially at least).", "403" ], [ "Command & Colors: Ancients (hereafter CC:A) is deceiving. After the first few sessions I was disappointed, the game seemed too simplistic and abstract. CC:A, though, has a depth with belies its simple rules and mechanics, and which only becomes apparent after repeated play.\nThis review assumes familiarity with the mechanics of the Command & Colors system shared with Memoir 44, Battle Cry, and Battlelore. If you are reading this, you probably already know the basic card play mechanic and the resulting orders for ‘X’ units on left/center/right. If not, there are many other reviews on BGG that you should read first in order to best understand this review.\nInstead, this review will focus on several key mechanics that make CC:A a good simulation of ancient warfare (far better than is generally recognized) while remaining any extremely fun and playable game. I will also compare CC:A to Memoir 44 and Battlelore, in order to demonstrate why CC:A is the best of the bunch (I haven’t played Battle Cry and can’t comment on that).\nI feel I must apologize for the length of the review. I tried to accomplish three things: first to compare CC:A to its Command and Colors siblings, second, to explain why it’s a great game, and finally, to provide some historical basis for why I thinks is a better simulation than is generally acknowledged. If you want to skip the historical references, I italicized them so you can pick them out easily\nComponents\nFirst a word about the game’s components. Due to the number of comments on BGG about GMT components, I’ll go more in depth here than for most of my reviews. Please feel free to skip ahead to the game play section if components aren’t a big concern of yours.\nThe map\nThe map in the base game is marginal. It is a heavy cardstock map (GMT’s ‘deluxe map’) similar to that found in Twilight Struggle. Usually, paper and cardstock maps don’t bother me since I simply cover them in plexiglass. But for a game like CC:A, this is a less than ideal solution, since CC:A is a very portable game otherwise: simple to teach and quick to play. Lugging around a piece of plexiglass hurts the game’s portability.\nDon’t believe those that say the map doesn’t lay flat, a simple back fold will fix that every time. A more vexing problem is that, due to the way the map is sliced for folding, when laid flat the map ends don’t meet in the middle, leaving a small gap in the middle of the map.", "993" ], [ "I also don’t care for the large game title in the middle of the map, but that tends to disappear once the action gets started.\nThe mounted map found in expansions #2 and #3\nFortunately there is an easy map fix out there. Buy either expansion number 2 or 3; each includes a true hard mounted map. For a game this good, you’ll want the expansions anyway (all of them!) so this is not a big deal to me.\nupdate: Newer versions come with a mounted map, problem solved!\nThe dice\nYes, I’m nit picking but I didn’t really care for the dice either (particularly the now-retired hollow ones in the first edition). Again, though, there is an easy fix: the really nice wooden dice from Valley Games. According to their site, the dice will be back in stock in September 2008 – or you can check ebay if you can’t wait. Again, a small investment ($7) that will increase your appreciation of a fine game.\nValley Games custom dice\nThe blocks\nFor certain games, I love plastic miniatures. Descent is a game that absolutely requires them, and in Memoir 44 they work well. For CC:A however, blocks are flat out better than miniatures. First of all, they are more colorful. I like Memoirs green and field-gray armies fine, but Battlelore’s single color and shared sculpt armies just don’t cut it for me, and pretty much require hundreds of hours of painting to look good. By contrast, CC:A blocks looks great after a few hours of applying stickers. Second, in their straight lines they are move evocative of the dressed lines of troops that made up the ancient battlefield. Third, with so many different troops types, the cost of miniatures would have been prohibitive. And the variety of unit types is one of CC:A’s main strengths. Finally, the blocks are easier to move as a group.\nDress those lines soldier!", "581" ], [ "The skinny: Kingdom Builder is a 30 to 45 minute terrain control game. Players alternate placing a few of their pieces each round on the randomly generated board until someone runs out of pieces and the game is scored based upon scoring criteria randomly selected before the game begins. Although skill plays a part in victory, luck plays a larger factor in most games.\nWhat type of game is it?: Kingdom Builder falls into a category of games that I call ‘filler’ games. It is a good option to fill some time with friends while waiting to do something else. What are the characteristics of a good filler game? It is quick (to set up, to learn, and to play) and there is enough luck involved in the game that new players have a reasonable chance to win.\nGame length: Although a new player’s first game will often take a few extra minutes, this game pretty consistently takes less than 5 minutes to set up, roughly 5 minutes to explain, and about 10 to 15 minutes per player for a typical length of 30 to 45 minutes.\nMy key rule for game length is that a game should end within about 15 minutes of someone being 'out of it'. In a 30 to 45 minute game, a player can spend nearly half of the game ‘out of it’ without it being unreasonable. In a 3 hour game, all players must be ‘in it’ for almost the entire game. 'In it' and 'out of it' do not necessarily turn on a player having a chance to win - it just requires the player to feel like their contribution is important and/or fun.\nIn this game, it is rare that a player is entirely out of it before the middle of the game. You may feel like you’re starting to fall out of contention if you have a bad start, but it is very possible to make a comeback from the worst of starts if your luck changes.\nGameplay: Players will have a ‘hand’ of one terrain card that will determine where they can place 3 of their pieces on their next turn.", "884" ], [ "When placing their pieces, players must place them on the selected terrain type and – if possible – adjacent to one of their pieces already on the board.\nIf the players place their pieces adjacent to a few special locations spread out over the board, they will be able to gain special abilities that allow them the option to do something once per turn – either play additional pieces, or move existing pieces – on all later turns. Although placing your pieces adjacent to the special locations does not usually directly give you points, those special abilities often provide a significant advantage over the remainder of the game, especially if the ability is gained early. This is especially true because these advantages often make it easier to grab additional special abilities in the succeeding turns, causing an exponential advantage.\nLuck: Every game can be describing by the balance between luck and skill. In KB, luck plays a larger part in victory than skill, but both can have a significant impact. A skilled player playing with three careless players will win most of the games, but luck can give victory to a player utilizing very basic strategy.\nThe primary luck mechanism in the game is the drawing of cards to determine the type of terrain that you will place your pieces on during a particular turn. You’ll often have many options for how to place your pieces on the indicated terrain (although it is possible to have no option what-so-ever by the middle of the game), but there are certainly times when there is a significant advantage to being able to place your pieces on a given terrain type of your turn.\nThe luck factor is never more significant than on the first two rounds.\nThere are ‘better’ and ‘worse’ places to place your first pieces on the first turn. If you draw the right terrain type and have the option to place in a ‘good’ spot, you can end up with a significant advantage over less fortunate players. The things you’re looking for in the early placement are the gaining of useful special abilities by placing pieces adjacent to special locations and limiting the types of terrain adjacent to your pieces so that you will have more options in where to place your pieces as the game goes forward.\nThe luck factor remains strong on the second round. No matter how you place your pieces on turn one, there will now be a few types of terrain adjacent to your existing pieces at the start of turn two and a few types of terrain that are not adjacent to your terrain. If you draw a card for a terrain type that is *not* adjacent to an existing piece, you’ll have many options in how to place your pieces that turn.", "937" ] ]

[ 10176, 5106, 10443, 3326, 6678, 3430, 1087, 6354, 8324, 537, 1478, 5442, 1181, 3916, 1835, 556, 8226, 7146, 9529, 5999, 3300, 1279, 4015, 3979, 422, 10624, 5514, 5923, 2781, 2111, 11419, 3509, 8213, 8193, 8961, 1639, 5810, 4851, 4272, 3738, 9499, 8569, 9629, 7748, 120, 6125, 3931, 3480, 3031, 57, 5006, 7437, 5712, 4282, 10247, 859, 9988, 6151, 3861, 3468, 7543, 4888, 4225, 7834, 4933, 2188, 6504, 3708, 1105, 3723 ]

[ [ "There are really two aspect to this :\n1) Will increasing roll stiffness improve handling to an extent which offsets any increase in weight by adding extra chassis members ?\n2) If yes what is the best strategy for improving the stiffness of the chassis.\nThe issue here is that this is a fairly simple ladder chassis so we are really looking at creating some sort of ladder/spaceframe hybrid. However we also need to consider that fact that the rear suspension is pretty basic in the form of longitudinal leaf springs so there is no guarantee that stiffer is better without identifying specific characteristics which you need to improve. Eg increasing rear roll stiffness isn't necessarily better unless this is identified as a limiting factor on performance.\nIn some ways it might be a more productive exercise to investigate where you can loose weight by removing materiel form the exiting chassis by identifying areas where it is under-stressed. Apart form anything else this should definitely give some easily quantifiable benefit.\nIn terms of an assignment it may also make more sense to demonstrate how a space-frame chassis could give the same torsional stiffness for less mass.", "333" ], [ "Again this give your project a much more well defined objective.\nFor example if you manage to find a way to make the existing chassis 10% stiffer it is then very hard for you to show what real world performance benefits this gives without actually carrying out the modifications and testing them. On the other hand if you can make it 10% lighter for the same stiffness that is a very obvious benefit.\nI would also add that having a project with a well defined strategy for improving a design is fundamentally better than just changing some arbitrary design parameter without any clear idea of how it will improve performance.\nSo project titles like 'A worked example of the weight advantages of a space-frame vs ladder chassis' or 'Reducing the weight of an MGA chassis' will make much more sense to an engineering professor than 'Showing that adding more mass to a structure can make it stiffer'.\nEg say you make it 10% stiffer and 10% heavier...is that better ? Unless you can prove it is better the whole exercise is a bit pointless. If it was an experimental exercise things would be a bit different.\nThe point here is that is any scientific and engineering experiment you need to be able to reach some conclusion. If your intended approach didn't work that is fine as long as you can say that it didn't work and why what is bad is when there is no way to tell withing the scope of the project whether it was worth doing or not.\nEg 'I investigated whether it was practically possible possible to lighten the chassis of an MGA using the following strategies but none of the approaches I used were effective' is useful information.\nHowever 'I made the chassis of an MGA 10% stiffer by increasing its mass by 10%' doesn't really tell you anything useful, unless you can add further information how this improves its performance.\nAs an aside there is also the fact that for classic cars (in th e UK at least) any marginal increase i performance has much less value attached to it than preserving its authenticity and originality.", "441" ], [ "History tends to teach us that attempting to design something without having a clear idea of what you ultimately want to achieve rarely works out well. Equally the definition of the problem to be solved should address the underlying problem, not just be an outline of a proposed solution.\nThere is, of course, a perfectly valid place for open-ended or speculative research and development, but this isn't quite the same thing as actually designing something.\nOften, if the requirements of a design seem very flexible it's because they haven't been defined well enough. The requirements should define what you want to achieve not a wishlist of 'features' which may or may not assist in solving the core problem.\nOf course context matters a lot.", "693" ], [ "For example if you are a member of a design team it may well be that another designer will give you a very specific set of specifications. Say you are designing an alternator for a specific engine the lead designer may well tell you specifics like maximum current capacity, duty cycle, average current capacity, voltage tolerance, maximum mass, environmental durability metrics and life expectancy.\nOn the other hand if you are developing an overall design concept for a car you might be negotiating rather more diffuse goals with strategic marketing people who might very well have rather more abstract objectives in mind and it is when it comes to 'designing' a marketable product rather than a strictly engineering a solution to a well defined problem.\nThis ultimately comes down to the fact that the goal of 'what can I design that people will buy at a profitable price for me' is not a strictly engineering problem. In the same way that 'how can I improve the reliability of this pump without increasing its cost too much', very much is.\nSimilarly anyone who has worked in any kind of freelance capacity will be well aware that what a client says they want is often a statement of how they imagine the problem should be solved rather than a definition of what they actually want the design to achieve.\nI think that there is a good argument that one of the defining skills of engineering is the ability properly identify what the real problem/need is without presupposing a particular solution and similarly to be able to differentiate between problematic symptoms and their underlying cause.", "284" ], [ "1) In an engineering context efficiency has a very specific meaning ie it is the ratio between the energy you put into a system and the useful work that you get out. In itself this doesn't tell you very much about the amount of pollution produced in the process.\nFuel economy is a bit different as it considers the overall energy(fuel) use of the car as a whole system and while engine efficiency is part of this the mass and drag of the vehicle are equally important.\nPollution emissions is more closely related to fuel economy than efficiency but even then they are not identical. Clearly all else being equal if you burn more fuel you produce more emissions and equally an efficient engine is not necessarily clean, indeed there can be situations where emissions and efficiency are in conflict (especially in the case of NOx emissions).\n2 & 3) Fuel economy is the main selling point for diesel engines. Even if the fuel is not cheaper per litre (in fact it has been substantially more expensive than gasoline in the recent past) the overall savings in fuel uses can be significant, especially for high mileage users. In very general terms diesel engines provide more low rev torque and are more robust and durable\n4) Diesel engines tend to produce more emissions which are immediately dangerous to humans, although this tends to be a local problem first and foremost, particularity in urban areas.\n5) It depends, carbon dioxide is an asphyxiatiant in large enough concentrations but not actually toxic per-se, carbon monoxide is (sort of) toxic in that it binds to haemoglobin and can cause asphyxiation although this is only a real problem in moderate concentrations in enclosed spaces rather than being a long term cumulative toxin.", "479" ], [ "Actually one of the biggest concerns with diesel is particulates especially nano-scale carbon particles (soot) which can accumulate in the lungs with the problems associated with any fine particle inhalation and may also be small enough to cross biological membranes.\n6) In some cases reducing NOx emissions can be in direct conflict with efficiency as they are produced more readily in lean-burning, high compression conditions which are preferred for efficiency. There is also the fact that catalytic converters (which are intended, among other things, to Reduce NOx emissions) require fairly specific exhaust conditions to work properly and can be damaged and clogged by the particulates in diesel emissions. There are also diesel particulate filters but these are themselves fraught with engineering challenges and, in particular, tend not to work well in the low mileage, low speed conditions encountered in urban driving where particulate emissions are the biggest problem.\nHaving said all of this there is a difference between the health effects of local pollution and the global effects of more persistent emissions. CO2 and its effect as a greenhouse gas is the obvious one but there are also more general effects from petroleum extraction, handling and processing to consider.\nEqually you can also look at the dangers inherent in the fuel itself. Gasoline is certainly more dangerous to store and handle and being more volatile can contribute to atmospheric pollution just by evaporating.\nYet another complication is that many fuels now have at least some bio-fuel component ethanol for gasoline and vegetable oils for diesel.\nAlso in this context technology is changing rapidly in response to consumer demand and government regulation so there is always a danger of comparing apples and oranges eg a 2 to 5 litre truck engine is a very different thing from a 1.2 litre hatchback regardless of petrol vs diesel.", "479" ], [ "The key thing here is that a turbo extracts energy from the exhaust which would otherwise be lost to the environment, this means that it has the potential to improve the thermal efficiency of an engine.\nAt its simplest a turbocharger uses a paired turbine and compressor to pressurise the air inducted into the cylinders. Normally aspirated engines just use atmospheric pressure to 'fill' the cylinder which costs a certain amount of engine power as the descending piston needs to 'suck' air through the inlet port via ducting and filters, not a lot of power but a bit.\nIn addition having a higher pressure air charge in the cylinder means a greater mass of oxygen is available so a greater mass of fuel can be burned or the same mass of fuel can be burned more completely so you can get more energy per cycle or extract more energy from the fuel. This is especially the case at higher RPM where the ability to get enough air into the combustion chamber in the time available becomes a limiting factor.\nThis also means that you can get more power out of a smaller capacity engine block for relatively small overheads in terms of extra ancillary equipment especially for moderate boost pressures.\nIt is also worth noting that turbos can have a significant role to play in hybrid power trains, particularly as they can substantially increase the power to weight ratio of a given capacity engine at relatively constant RPM. It is also possible to use a turbo for electrical power input/output when connected to motor/generator here the turbo can output surplus power to the electrical storage system and similarity electrical power can be imputed to keep the turbine spinning in its optimum range to reduce or eliminate turbo lag.\na real world example of this is current generation F1 engines which are now getting close to 1000bhp peak output with a thermal efficiency of around 50% (better than any IC road car by some margin) with a capacity of 1.6 litres (from which typical consumer engines generate about 100bhp) albeit at the expense of a service life measured in tens of hours.", "479" ], [ "Conventional automatic transmissions have a torque converter which uses a viscous rather than a rigid coupling to connect input and output. This performs a similar function to a friction clutch but doesn't require manual engagement. Also automatic gearboxes are based on epicyclic gear trains so all the gears are permanently meshed with each other and ratios are selected by locking different combinations of the sun, planet and annular gears so there is no need to match different shaft speeds to each other.\nSequential gearboxes use a combination of straight cut (as opposed to helical) gears and dog clutches with gears engaging by sliding along the input and/or output shaft so the gears never go fully out of mesh with each other but rather are either locked to or freely spinning on their respective shaft. Again this means that it is not necessary to match input and output speeds, however a clutch is still required to start from a standstill. Motorcycles, for example typically have sequential gearboxes and hand operated clutches.\nThe more modern type of auto/semi-auto gearbox typically uses twin wet plate clutches to change between pre-selected gears in this case the gear selection and clutch engagement is done by act actuators which are controlled by a computer.", "479" ], [ "In many cases they can be operated in as fully automatic or semi automatics where the driver shifts up or down by operating a paddle or lever. So while they do have a clutch is it not manually operated to change gear. Although, as in a sequential gearbox, manual clutch operation may still be required to start from a standstill often this will be an additional paddle or paddles. Although many semi-auto transmission will also incorporate and anti-stall system which automatically releases the clutch if the revs drop below a certain level at low speed.\nSo from the perspective of the driver there are 3 main cases\n* Full auto (either conventional auto or modern semi auto in full auto mode) press accelerator pedal to go and the brake to stop and the clutch (or equivalent) sorts itself out automatically eg with automatic transmission if you brake to a stop the engine won't stall so no manual clutch operation required.\n* Sequential/semi auto : manual clutch operation is required to start/stop but not to change gear. Often this will be a hand clutch.\n* Manual : manual (usually foot pedal) clutch required to start and to change gear.\nThese cover the most common systems, although there are various other transmission types around.\nSequential gearboxes are most common on motorcycles and some classes of competition cars (especially those heavily adapted from road cars (eg rallying).\nMost conventional road cars have either conventional automatic or manual transmissions.\nComputer controlled semi-auto/auto transmissions are mostly found on high-end sports and racing cars eg F1 and GT formulae.\nThere are also automatic transmissions which allow for an approximation of manual gear selection eg the Porche Tiptronic system and it is also possible to automate a conventional manual transmission, although this is a lot of complexity for no real gain.\nFor the sake of completeness there are also centrifugal clutches which only engage above a certain engine rpm but these are only really found on things like chainsaws and self propelled mowers. Also steam piston engines don't require a clutch as they can develop torque from zero rpm.\nIt is also worth noting that for a driving simulation, unless you have really good haptic feedback in the control hardware it will be very difficult to simulate the feel of a manual clutch", "479" ], [ "Against the Clock\nIntroduction: Against the Clock\nAs an avid racing cyclist, pitting yourself against the clock is nothing unusual in a time trial.\nSo what better way to portray time than with a cyclist.\nIn this project I will create an animated cyclist representing the passage of time.\nThe will be accomplished using a combination of 3d printing and manual machining.\nThe timing and control for the animated clock will be accomplish using in the main a previous Instructable.\nMicro Binary Clock\nWith some modifications these being the RTC and the motor controller.\nSupplies\nPerspex sheet 160mm * 205mm * 5mm - Black\nPerspex sheet 75mm * 150mm * 5mm - White\n3D Printer\nBlocksCAD\nCura\nMicrobit\nKitronik All-in-one Robotics Board for BBC Micro:bit or similar\nAdafruit DS3231 or similar\n28BYJ-48 5V stepper motor or similar - Qty 2\nServo Motor 5V or similar.\nMF52ZZ 2x6x2.3mm - Qty 8\nM3/10mm though hole threaded stand off. - Qty 19\nM3/15mm though hole threaded stand off.", "134" ], [ "- Qty 2\nAluminium sheet 6.5mm * 17mm * 1.5mm\nDrill bit 6mm\nDrill Bit 3mm\nDrill Bit 10mm\nM3/10mm bolts - Qty 26\nLEGO cross axle 55mm min\nLEGO cross axle 23mm\nStep 1: Cyclist Design\nThe cyclist will be 3d printed and was designed using BlocksCAD.\nThe main moving parts will be the legs and these will pivot at the hips and the knee.\nRather than creating a separate pedal, the foot became the pivot point with the crank reducing the component count.\nHowever as a result the Q factor or 'stance width' needed to be taken account by a spacer between the foot and the crank. This was integrated within the crank.\nThe hips would be an anchor point for the cyclist in addition to the hand.\nThe distance from the hips to the toe needs to be such that the leg is not totally straight at dead bottom centre allowing the leg to retract on the upstroke to stop the leg locking out.\nToo long a crank will cause the leg to lock out, you will often see this on real cyclist thereby they rock their hips to compensate for the extra length.\nShort cranks in this model being less of a problem.\nAs should be the case in a real time trial situation the upper torso will be static adopting a aero tuck resting on the forearms.\nFor simplicity there will be no bicycle but this will be accounted for by the riders body position and the wheels.\nThe wheels will have only one spoke each these represent the hands on the clock the rear representing hours and the front representing the minutes.\nThe pedals will be connected to a chain ring in this case via a LEGO cog and this in turn will be driven by a larger LEGO cog this in turn will be driven by a motor. 3d printed cogs are included with the design if LEGO cogs are not available but being the same size requires moving the motor up to remove the gap.\nYou will however, need a cross locating axle or drill this out for a round axle.\nTherefore, as the cogs rotate the chainring and foot will rotate around turning the legs.\nEverything, is mounted on a single sheet of Perspex forming the background and the support for all the pieces.\nThe files for the cyclist and wheel hands can be found here:\nYouMagine – Against the Clock by <PERSON> – <PERSON> 🎨\nStep 2: Support Board\nAgain this was designed using BlocksCAD being a template for the holes.\nTherefore, the fact that this board is smaller (top and right edge), than the final support board is not an issue.\nThe left hand corner is the reference.\nThis variation of the template is due to the completed board being larger than my 3D printers build area.\nIt also enabled adjustment during the pre-fit to save wasting a Perspex sheet.\nHaving done the pre-fit any measurement adjustments were fed back into the template.\nA couple of slots were included into which feet would be fitted later, this is a 68mm Perspex circle cut in half and slotted to fit in the support board.\nStep 3: Cyclist Build\nOnce printed and removed from the brim and trimming applied the pieces were assembled.\nStarting with the arms these are attached to the outer torso at the shoulder with a M2.5/18mm bolt this lines up with a similar positioned hole in the central torso so a small protrusion will anchor this the hole are counter sunk to keep the torso elements flush together.\nThere is a left and right outer torso.", "226" ], [ "Accidental early detonation\nAs stated in other answers stopping the arms race from a technological point of view is hard to impossible. Making scientist and/or the general public unwilling to fund/participate in the development is probably easier. For nuclear power this has precedent in the Chernobyl accident which has had a severe impact on all research into nuclear power that still persist today.\nThe accidental early detonation of the (would be) first atomic bomb while still at the production facility would cause a major set back in the research since it both destroys evidence of what has gone wrong and kills a lot of the scientist and engineers necessary to build the bomb in the first place. Since it will be hard to find out what has gone wrong it will be hard for the scientist to say if it was a minor problem or a major design flaw. The effect will be that anybody will be very hesitant to continue with the project or try to start a new project.\nFor the disclaimers:\n* An accidental atomic explosion can be caused by a simple very small effect such as a faulty wire presumably.", "435" ], [ "Although I am not sure what fail safe mechanisms they had in place during production of the atomic bomb.\n* This scheme would set back the USA but not necessarily the USSR although scientist there might become quite nervous about development. On the other hand if the USA didn't develop the atomic bomb the USSR might be less inclined since there would be no mutually assured destruction arms race.\n* Delaying it to 2010 might not be possible with a single explosion but should come from later treaties. The UN banning the development of nuclear weapons due to the risky nature of it linked to the explosion seems feasible.\n* You could argue that an atomic explosion is in fact an atomic bomb, but I would say that for it to be a \"bomb\" it should be stable and controllable which was not the case in this scenario, thus it should not qualify as an atomic bomb.\n* As a minor side note, but that would completely depend on the story. With no atomic weapons race between the USA and the USSR they have ample opportunities to get into conflict anywhere else, be it normal war, space or anything else. The space race could for instance give such a drain on both of their resources that they wouldn't have enough resources left for the development of an atomic bomb making the year 2010 more viable.", "477" ], [ "Controlling temperature using PIDs on two separate controllers\nCurrently, I am controlling how much material is burning to control temperature using a PID loop. I want to achieve tighter control by also slowing down or speeding up the fan in response to temperature changes. I'm looking to find an algorithm that would allow these two to work together.\nSo what is the real question are you looking for an algorithm to use as a second separate controller?\nThere is one very basic problem with this approach. One controller will influence the other controller so you will have an unstable control cycle. For example as the fan reduced speed to reduce the temperature the argue speed would increase to raise the temperature back to it's original point, the fan would then reduce speed further to compensate.\nThis is a common problem in air conditioning where both humidity and temperature control are needed one fights the other for dominance. Although the example you have given is more complicated some of the basics remain the same. You cannot use two independent PID controls. A special set of circumstances exist in which one control (I will call it a channel) needs to have priority control.\nWhat is required is a two channel PID controller with a priority control option.\nTo be honest I have never come a cross an algorithm for this that works successfully except in a dedicated controller like Eurotherm or someone similar would manufacture. 20 years ago they cost over 2000 usd.", "842" ], [ "(you are paying for the development costs). Today I have no idea of the costs. Algorithms for PLC's from Siemens and the likes are next to useless and my old company asked a university to estimate a time and cost to develop such an algorithm They estimated 2 years at which point the cost became irrelevant and the idea was scraped.\nYour problem is infinitely more complexed than trying to control Temperature and Humidity. They are just two independent states that are physically related. So you can control each and just give priority to one. What you are trying to do is create 2 channels which are both based on temperature so even though one channel could be given priority it will still produce conflict with the second channel and the result would be a totally unstable control cycle. I think even <PERSON> would have considered this a considerable challenge.\nThe only way forward that I can see is to decide on an alternative control strategy that provides two independent control channels, or scrap the idea.\nHowever there is some light at the end of the tunnel If you had addressed this question to a cooking web site they may have given you better advice.\nA smoker with little airflow, like some electrics, creates a larger stagnant bubble of air protecting the meat from smoke. Rapid, random air movement breaks up the bubble. For example, a strong convection fan.\nWithout the smoke, you might as well be grilling.", "115" ] ]

[ 8281, 10281, 2169, 8603, 10668, 3380, 248, 8915, 3824, 5086, 7818, 3144, 8058, 3880, 9137, 7006, 10823, 1894, 9711, 2114, 7344, 1939, 1924, 10741, 4296, 8201, 5799, 2548, 121, 4676, 1199, 11357, 2849, 10740, 3607, 2531, 7969, 4429, 920, 4801, 1713, 10341, 1074, 4009, 4923, 893, 1556, 10201, 9118, 10001, 185, 4088, 8545, 6349, 7872, 3505, 11316, 6152, 1274, 3835, 3452, 6323, 6873, 8205, 2376, 8127, 10889, 9648, 3990, 2525 ]

[ [ "How to Solve Sudoku Puzzles (beginner and Advanced)\nIntroduction: How to Solve Sudoku Puzzles (beginner and Advanced)\nIn this guide I will explain all of the tricks I have found to reduce the possibilities in a sudoku puzzle and ultimately solve it. Each step in this instructable will be of a different trick so if you come across any you already know of then feel free to skip ahead to the later ones.\n**For beginners** let's get to know the puzzle itself, a sudoku puzzle is a grid of 9 small squares horizontally by 9 small squares vertically. where after every 3 there is a thicker line and throughout the puzzle various numbers are placed. The object of the puzzle is to figure out the places where you have to place the numbers 1-9 in order to have every single row, column, and block filled up with a 1, 2, 3, 4, 5, 6, 7, 8, and a 9. Most sudoku puzzles are made so that there is only one final solution after sifting through all the options and filling in all the blocks. **For beginners**\nThe last thing for this introduction will be my order of doing things:\n1. I use 4 terms regularly, a block is the 3x3 area of squares separated by the thicker lines, a row is the horizontal line of numbers, a column is the vertical line of numbers, and a cell is any individual square on the board.\n2. each trick will be given *'s for how annoying I think they are to find and use, but they will be ordered by similarity (ie.", "74" ], [ "the pairs/triples/quads will be together but it may be more conducive to move onto the later tricks before thinking in quads.)\n3. on each trick I will first explain what to do, then show how it works in the example image, and finally the logic behind why it works.\n4. I like to enjoy myself while solving them, so the steps may seem a bit inefficient as i voice my own standards.\nStep 1: Visualization*\nLook for single cells within the blocks that do not intersect any horizontal or vertical lines that could be drawn from one of the numbers on the board, then place that number when you find them. An easier way to think of this is find all of the 1's on the board, draw mental lines vertically and horizontally off all of them, then see if you can find any blocks where all but one cell is either crossing these lines or filled by other large numbers. When you do, you would know that you can fill in that cell with a 1; this can be done with any number.\nIn my example given I drew the lines off of every 8 on the board and in the upper right block there is a single cell that does not cross any of them, so that block has to be an 8. Take care to not fill in the middle 2 blocks however, they both already have an 8 and the puzzle would be wrong at that point.\nThe logic behind this move is that in order for every row, column, and block to have the numbers 1-9, absolutely no row, column, or block can hold the same number twice, so by visualizing lines off of every single instance of a number, you effectively show yourself all the places a number can't go.\nStep 2: Candidate Lines*\nSometimes while visualizing for places to put numbers you come across blocks where 2 or 3 cells in a line could possibly be that number but none of the others in the block. This is a useful piece if information because the line formed by those cells also cannot hold the number in question. I often mark in the number in smaller writing in cells like these as a note to myself that there is a candidate line\nIn the example there are only 2 spaces for a 1 in the bottom right block and the line formed cuts off more possibilities letting you figure out that the red square is the only cell in the middle right block that can have a 1.\nThe logic behind this is that when the candidates are in a row but nowhere else in the block, it doesn't matter which of the 2 or 3 it is, on that one line the slot will be filled and no others in any other block on that same line can share the number.\nStep 3: (Optional) Counting*****\nTo fill in more possibilities you could look through each cell and count all the numbers in the same block, column, and row, but I personally find this to be too much work with too little gain and cannot be bothered to show it.\nStep 4: Repetition!\nthe previous steps don't end once you've done every number, a large majority of puzzles are easy enough that they can be solved with just the first two steps, you just have to keep going back through the cycles as more and more numbers get filled in until you finally can't find any more.", "242" ], [ "Icosahedron Sphere (from A4 Papers)\nIntroduction: Icosahedron Sphere (from A4 Papers)\nThis icosahedron sphere is a fun combination of craft and math (no calculations needed). It's made by connecting many small triangles, with no glue, to create a very stable sphere.\nThe building blocks are non-curved triangles, and by connecting them into a combination of hexagons and pentagons you create a curved shape. Because of the flexibility, or \"hinge\", between each 2 connected triangles the result is a more spherical shape.\nSupplies\nAll you need for this project is:\nA4 Paper - 100gr sheets give good stability and are easy to fold.\nScissors or a blade.\nI used two colors of paper, because its prettier and easier to understand in the images. In this case you need -\n1 1/2 A4 sheets of color A (pink)\n1 3/4 A4 sheets of color B (blue)\nStep 1: Cutting Up You Paper\nThe paper has to be cut into equal thickness long strips. I chose the pink paper for the triangles and the blue for the connectors.\nPink paper: This is a bit more tedious with a lot more folding and cutting but the end piece size is exactly 1 triangle.\nBlue paper: This is less cutting and folding, but you have to be accurate to get the strips equal width.\nStep 2: Creating the Folding Marks\nIn order to construct the shapes you need the folds to make exact squares. This is a simple method for getting those fold points accurate (without having to pull out a ruler).\n(Anybody who has owned an old printer with continuous feed printer paper has probably done this many times)\nStep 3: Triangles and Connectors\nBecause of the way the pink paper was cut, each piece can now be folded into a triangle. These are equilateral triangles in which each side is the same length. The strips are longer than 3 squares, and this overlap creates the stability of the triangle.\nThe blue strips need to be cut into connectors- each connector is 4 squares long (cut at the fold marks).\nStep 4: Basics of Putting Together Triangles\nEvery 2 triangles are connected by 1 connector piece. The connector goes through both triangles and wraps over the shared sides, and then is tucked in between the 2 triangles.\nThat way each triangle side is completely wrapped in blue and there is a \"hinge\" connecting the two triangles.\nStep 5: General Principles of Putting Stuff Together\nIt is extremely important that when you start connect multiple triangles the \"hinge\" is always on the same side.\nThere are 2 basic shapes -\nPentagons - created from 5 connected triangles. These units are curved and their shape is stiff (non bendable)\nHexagons - created from 6 triangles.", "294" ], [ "When no pressure is put on them these units are flat. But these units can be bent along any diagonal.\nStep 6: Construction Rules\nTriangles are now added one by one to create the shape. Now you need to choose a rule to follow. This seems complicated but it really isn't too bad, as long as you consistently follow the rule you chose you will end up with a sphere.\nThe rule options:\n1. Every 3 pentagons are connected by one triangle. 12 pentagons and 19 triangles.\n2. Every large triangle (made out of 4 triangles) has a pentagon at each corner.\n3. There is a hexagon attached to the end of each pentagon.\nYou might notice that these rules are basically the same...because they are!\nThe only difference is which 'block' your focusing on when you start connecting your pieces (pentagons, large triangles or hexagon-pentagon connection).\nI personally follow option 2\nStep 7: Adding Pieces\nMake 1 pentagon and put it to the side.\nStart constructing going from one hexagon and adding triangles. As you move up in your chosen rule you will create a kind of semi-sphere.\nIf you think you got lost, look for that rule that you chose in the connection between pieces.\nKeep building until you reach a sphere that is missing a five point star.\nAt this point you should have left 5 single triangles and the pentagon you put to the side.\nStep 8: Preparing to Close the Sphere\nWhen you reach this stage it becomes harder the thread the connectors through a triangle and then pull them back up again.\nThat is why the last 5 triangles are added with the blue connector already attached.\nEach triangle is connected to the 'point' of the missing star. This means 2 sides connect to 2 triangles already in the sphere.\nThe remaining unconnected side will already have the blue connector in.\nStep 9: Finishing the Sphere\nYour sphere now has a missing pentagon - but the blue connecting pieces are already there.", "220" ], [ "Origami Stars\nIntroduction: Origami Stars\nHave you ever made a wish and hoped for it to come true? Have you ever felt as though you needed a little luck? Then you'll love these origami stars! The fun idea behind these stars is that each one contains a wish of your own, or you could make them when you need a little luck. Then you keep making them until your container is full. Your wishes come true or you get lucky once the container is filled! You decide their purpose, but they are still a fun activity that anyone of any age can make.\nProblem Statement: What kind of paper stars are the most efficient to make?\nConstraints: Constraints for making these stars would be; limited knowledge, and lack of materials like paper.\nProblem Research: While researching my problem, I found many ways to make stars out of paper. There were many options available like puffy stars, thin stars, pointed stars, and stars that varied in size.\nBrainstorming Ideas: There were many ideas I had for making these stars after researching the problem. Some ideas were that I could make small stars to fit the container, and another idea was that I could make softly rounded stars because they seemed simple to make.\nDesigning a Solution: A solution to the problem would be that the most efficient stars are ones that are small in size and have rounded corners.\nSupplies\nSupplies you would need:\n* Construction Paper: preferably 10-12 inches long\n* Patterned Cardstock Paper\n* Scissors\n* Pencil\n* Ruler\nStep 1: Measure\nTake your construction paper and measure about half an inch. Then draw a vertical line across your paper.\nStep 2: Cut\nCut out along the line you drew then write your wish on that strip about 2 inches away from the corner.\nStep 3: Fold\nFold your strip into a similar shape like this, make sure the wish goes under.\nStep 4: Fold\nTake the little piece on the right of your strip and put it into the loop that was made in the previous step. Then press it down flat.\nStep 5: Fold\nThe little piece that is now on the left should be folded inward, if the little piece is too long then cut some off to line up with the pentagon shape.\nStep 6: Cover the Edges\nTurn over your strip so that the pentagon shape is facing downward and towards the bottom. Take the long strip and fold it over each edge at least once.\nStep 7: Fold\nIf there is some excess of the long strip that cannot cover another edge, take that piece and put it into the closest insert.\nStep 8: Make the Star Legs\nPress the middle of each edge inward with a ruler to create the star legs.\nStep 9: Star\nOnce each edge has been pressed, turn it over and now you have a star!\nStep 10: Make Star Bowl\nTake your cardstock paper and measure out 20x20 cm then cut it out.\nStep 11: Fold Paper\nFold your paper in half, and make sure the pattern you want is facing upward.\nStep 12: Fold Corner\nTake the top left corner and fold it towards the bottom middle of the paper. Then unfold it and take the bottom left corner and fold it towards the top middle of the paper.\nStep 13: Mark\nMark the creases that were created by the folds in the previous step with an X. Make sure that your paper is in rectangle form during this step.", "966" ], [ "Then take the bottom right corner and fold it towards the marked X on the creases.\nStep 14: Fold\nTake the piece you just folded in the previous step and fold it towards the right, then take the bottom left corner and fold it along the crease to create a right triangle and cone-like shape. Then fold that shape in half so only the cone is facing towards you.\nStep 15: Fold and Cut\nAfter folding in half, your cone should look like the picture above. Then cut along the diagonal line on the triangle shape so what is left is just the triangle. Then unfold the triangle that should now look like a pentagon.\nStep 16: Fold Into Triangle\nDraw a line like the depicted picture above. Then take the corner point under the drawn line and fold it upwards to create a long triangle. Make sure the triangle is centered. Continue drawing lines from one corner to the other to create a guide. Then keep on folding each corner point inward. The pentagon should get smaller and you should now see a star shape on your paper.\nStep 17: Fold Again\nContinue the previous step of folding upwards and making triangles. Draw lines on each corner end if you need a guide to know where to fold. Your paper should look like the above picture where the pentagon shape got smaller and there is a visible star shape.", "636" ], [ "Prototype Clay Pulley/Gear System\nIntroduction: Prototype Clay Pulley/Gear System\nThis project showcases simple machines working in tandem to pull a small weight. The construction of the project will mostly be made out of clay and wooden sticks (and glue).\nThe simple machines in this project are a pulley, wheel and axle, and inclined plane.\nThis prototype can be seen how a crane works. There is a motorized part (the gears) and a mechanical part (the pulleys). The gears transfer mechanical power through the gear belts and one of the gears is attached to the pulley wheel that will then transfer the power through the tension in the rope (in this case, the ribbon) between the pulley wheels to pull the weight.\nSteps 1 through 4 is optional, as this part is to create an elevated position for the simple machines to do work with a ramp that connects below the simple machine. Overall, the elevated position does not change the project's core idea, simple machines working together in an unified system to pull a weight.\nSelf Reflection\nWhen everything was done, I saw some issues in the final build.\nThe ribbon would slip off of the pulley's wheel, a simple fix would be making the pulley wheels larger and the grooves deeper. And using string instead of a ribbon, so the orientation would not change unlike a ribbon which could and did shift. Same goes with the rubber band, gluing two small strands proved to be difficult, so much so that at one of the combined ends was a large chunk of glue that would sometimes would not fit in between the grooves of the two gear wheels.\nNot all axles were leveled as I expected them to be, this is due to the supporting structures not being done properly. With a second pair of hands, this supporting structure design would have worked as intended.\nI do know if I continuing on and enhancing this prototype, it can become a more functional long lasting simple machine system made from clay and wood (and glue).\nSupplies\n* Air-dry clay\n* Wooden sticks\n* Hot glue gun\n* Glue sticks\n* Cardboard box\n* Scissors\n* Ribbons\n* Rubber bands\n* Paper Clip\n* Ruler\n* Wax Paper\n* Acrylic Paint\n* Paint Brush\n* Cup of Water (if needed for the clay)\nStep 1: Making the Foundation (Optional)\nTo create the rectangular box shape, cut two strips of cardboard approximately 14 inches by 6 inches.\nOn the width side (the 6 inches side), fold the ends roughly two inches straight up. Do this for both ends of each strip.\nWhen you place one strip over on the other strip with the flaps up (bottom strip) and down (top strip), it'll create a box with no internal supports - as you can see in the first picture showing the lengthwise side.\nNote: There are different ways to create a box. I used a method that would allow me to view the supporting structures and to easily attach the two strips together.\nStep 2: Making the Support Sticks (Optional)\nPlace a wooden stick on the inside of one of the cardboard strips with the flap going up.\nGrab a pair of scissors and mark the wooden stick at the height of the flap as shown in the first picture.", "215" ], [ "To mark the wooden stick, attempt to cut the wooden stick to leave a small cut in the wood. *1\nContinue to cut into the wooden stick (all around in 360 degrees) to deepen the cut as shown in the second picture.\nPlace the smaller end of the wooden stick over the edge of a table. Then push down the longer side as to hold it in place against the table. Next, with your other hand, push down the smaller end to break the wooden stick approximately. This would look similar to the third picture, flip the stick over and as done before, push down the smaller piece to break it off. *2\nSet the small piece against the larger stick. Mark on the larger stick like on the fourth picture to start the process to create another small piece.\nCreate 24 of these small pieces to use in the next step.\n*1 Note: You can mark the wooden stick with a pencil and then cut slightly into the wooden stick to break off the piece.\n*2 Note: Do be careful with this step, as splinters can appear from the broken ends of the wooden stick. Trim the rough pointy ends off by using the scissors.\nStep 3: Making the Support Structures (Optional)\nMake six marks on one of the cardboard strips similarly to the second picture. On the lengthwise side, the lines are separated by 1/4 of the length (2.5 inches). On the widthwise side, the lines are separated by 1/3 of the width (2 inches).\nNext, place four small sticks in each quadrant of each cross on the cardboard strip.", "276" ], [ "In perusing The Geek I have noticed that most reviews give general game information, and what I really wanted was what exactly goes into the gameplay. Is there area control? Blind bidding? Resource production? Or maybe some good old-fashioned luck? On top of that I really wanted to know was how these elements meshed together to form the gameplay. Like was it a strategy vs. luck game? How about tough choice resource management? Or maybe something like a concealed element blind bidding game. I believe this is the alchemy of the game, the part the makes each game unique. In each review I will go over the usual elements (Theme, Components, & Gameplay), but I will also give the Alchemy of each game, and also a Philosopher's Stone (my own feelings/thoughts) score for each game. Any feedback would be greatly appreciated, thanks for reading and enjoy!\nThe Alchemy of a Board Game -Cartagena\n(thanks <PERSON>)\nThe Usual:\nTheme: Each player assumes the role of leading six pirates trying to escape the famous prison of Cartagena. A boat awaits at the end of the escape tunnel for the lucky group of pirates who made it out as a group.\nComponents: The components for this game are of good quality. The cards are large enough to be easily read, although one of the symbols (the red pirate's hat) is not easily identifiable. I played the game many times before I realized it was a hat, before that I thought it was a ruby. But, that is really nitpicking the artwork. Speaking of which, the artwork nicely matches the theme of the game. The board pieces themselves are made of sturdy cardboard and shouldn't see much wear after many many plays. On each of the board pieces there are six symbols that match the cards in the playing deck.\n(thanks <PERSON>)\nStarting the Game: Each player starts out with six cards, and a set of six pirates in their chosen color.", "336" ], [ "The six board pieces are connected in any way that the players see fit, and are interchangeable. Then each players set of six pirates are set at the one end of the board, after the six board segments have been assembled. The escape boat is placed at the opposite end of the board from the player's pirates.\nGoal of the Game: The goal of the game is to have all your pirates reach the end of game boards, and the board the awaiting escape boat. The first player to have all of their pirates reach the escape boat wins the game.\nGameplay: Each player's turn consists of three actions. The two options that are available for those three actions are:\n1) Play a card from the player's hand and advance one pirate to the next available space of the same symbol that is on the card played. Each symbol on the board represents a one space. Any symbols that match the symbol of the card played that already have a pirate (any player's pirates) can be skipped. The player's pirate moves to the first open symbol that matches the symbol on the card played.\n(thanks Superfage)\n(In the above exmaple, almost all of the \"gun\" symbols are occupied by at least one pirate. This means that the pirate that is the furthest away from the escape boat, the yellow pirate furthest to the left, would be able to move to the \"gun\" symbol that is only two spaces away from the escape boat.)\nIf all symbols that match the symbol of the card played are occupied by pirates between an active player's pirate and the escape boat, the pirate immediately moves to the escape boat. In this way a player's pirate can move from one end of the boards to the other if all spaces of one symbol are occupied.\n2) Move one pirate backwards to the first symbol that is occupied by either one or two other pirates. If the space is occupied by one pirate draw one card from the deck, if there are already two pirates on the space the player draws two cards from the deck. There is a max of three pirates per space.\n(Thanks <PERSON>)\n(In the above example if the yellow player were to move his pirate backwards from the \"pirate hat\" symbol to two spaces to the \"knife symbol\" with the one brown pirate the player would pick-up one card. Also, if the brown player's turn they choose to move their pirate that is occupying the \"knife\" symbol backwards one space to the \"key\" symbol, that already has a green and yellow pirate, the brown player would be able to pick-up two cards from the deck.)\nAny space already containing three pirates, must be passed over for the next symbol that is occupied by only one or two pirates when moving backwards.\nThese three actions can be used one pirate, and or any combinations of pirates.\nThere is a variant included in the game that allows for less luck in the game. The above description of play is the Jamaica version.", "597" ], [ "Because all the simple methods would probably fail.\nThere are many maze-solving algorithms, check this wikipedia page: https://en.wikipedia.org/wiki/Maze_solving_algorithm Now the problems with these ones on are either the necessary time (remember, this is a race) or the lack of information in <PERSON>'s case:\n* Wall following a.k.a. Right-hand-method\nAs the others already mentioned, the Right-hand rule doesn't always work. I would add something to this: the rule provides a sure method if, and only if all the walls are connected to the maze's boundary, thus there are no loops; or on a maze with loops if both the entrance and the exit is on the same piece of wall. (See <PERSON>'s answer.)\n<PERSON> could not know if this is the case.\n* Random mouse method\nThis is the most basic one, but the drawback is obivious. The method is randomly choosing direction at every junction, and turning back at dead-ends. After an ernomous amount of time, this will with high probability lead to the exit.\n<PERSON> would still be in that maze...\n* Pledge algorithm\nThe algorithm is an enchanced wall following with a compass: you choose a direction as zero angle, and at each turn you add the (signed) turned angle to a sum. If the sum and the current direction are both zero, leave the wall and head forward to another wall. The problem is that the method, like the wall follower one, only works if the exit is on the outer wall of the maze. (The entrance could be anywhere though.)\nAgain, this one requires information <PERSON> didn't have.\n* <PERSON>'s algorithm\nFrom Wikipedia:\nThis method requires drawing lines on the floor to mark a path, and is guaranteed to work for all mazes that have well-defined passages. A path is either unvisited, marked once or marked twice.", "242" ], [ "Every time a direction is chosen it is marked by drawing a line on the floor (from junction to junction). In the beginning a random direction is chosen (if there is more than one). On arriving at a junction that has not been visited before (no other marks), pick a random direction that is not marked (and mark the path). When arriving at a marked junction and if your current path is marked only once then turn around and walk back (and mark the path a second time). If this is not the case, pick the direction with the fewest marks (and mark it, as always). When you finally reach the solution, paths marked exactly once will indicate a direct way back to the start. If there is no exit, this method will take you back to the start where all paths are marked twice. In this case each path is walked down exactly twice, once in each direction.\nThis may be the only method that could work for sure. Drawing on the floor, however, is not so pleasable during a race... And considering the possible magical propertities of the maze, even this one could fail.\nThe other two methods, the Recursive and the Maze-routing are too complicated to expect <PERSON> using them.", "242" ], [ "Cardboard Mini Combo Safe\nIntroduction: Cardboard Mini Combo Safe\nLocks and safes are very common in this modern world, when almost everything valuable needs to be kept secure. Obviously, cardboard isn't the best option as a holder for a very expensive item, but it can be cool to have. In this tutorial I will show both how a combination lock works and detail the steps I went through to make this cardboard \"prototype\".\nSupplies\nThe supplies for this project are definitely on the cheap side:\n-cardboard boxes (double corrugated is better for more strength)\n-standard printer paper\n-elmer's glue\n-hot glue sticks\n-pencil\n-cereal box\n-q-tips OR toothpicks\nOptional Supplies:\n-super glue (only needed if you want good durability)\n-resin (I didn't do this because of time and budget constraints)\nTools:\n-box knife\n-hot glue gun\n-pencil/pen/sharpie\nImportant note: If you want to make this out of wood, it would be be exactly the same process. Just swapping the cardboard with wood would be a great choice if you want extra strength. The only reason I chose cardboard was because I am on a budget and don't have much choice. You could also coat the cardboard in a few layers of resin to make it as hard as a rock.\nStep 1: Outer Shell\nThe outer layer is pretty easy to make. I started by cutting two 5''x5'' squares of cardboard. I then cut two 4.5''x5'' pieces and hot glued all four together. Try to be as neat as possible for a decent aesthetic later on. It is pretty self explanatory how these all go together.\nNext, cut four 4 1/4''x5'' squares. Later on, these will be lined upon the inside to double layer the whole box. However, I wouldn't do it yet because on one square you still need to cut a small section out that the bolt will rest in.\nStep 2: Combination Lock Mechanism\nThe standard design for combination locks revolve around discs. Basically, there will be three small circles, the discs, on a cylinder that are able to freely spin. On each disc there is a tooth that will meet up with the other disc when the dial is spun a few times. Each disc also has a notch in it. Only when all three notches are lined up can the lever fall into the notches and pull the bolt out. This video explains the whole mechanism in detail, although for my safe there are a few modifications.\nStep 3: Building the Lock\nYou'll want to start out by making the cylinder that the discs rotate upon. This is done by taking paper and wrapping it around a pencil with Elmer's glue.", "622" ], [ "Don't glue it to the pencil, but glue the paper so that it is a decently hard cylinder that the pencil can spin spin freely inside of. Next, cut out three circles from cardboard that are a bit over an inch in diameter. The measurements don't matter two much in this combination mechanism, just make sure it will fit in the final box. Punch holes in two of the circles that will allow them to slide onto the paper tube. You want a little bit of friction but not too much or it will hinder the ability for the discs to rotate. On the third disc, punch a hole the size of a pencil, which should be slightly smaller than the paper tube.\nNow add some teeth to the outer rim of each disc. Make sure it extrudes no more than 1/4''. Use the photos above for reference. In the end, when you rotate one disc, it should meet the teeth of the other discs until all three spin. Note that the middle disc should have two teeth, one on each side. Cut a notch into each disc with random placement so the combination will end up random.\nNow take some thin cardboard and cut it into strips 1/4'' wide and long enough to be wrapped around the paper tube. These are the sections that separate the discs seen in the pictures above. Slide two discs into place along the tube, 1/4'' apart, and glue the cardboard strips in between the discs to separate them and keep them in place. The third disc needs to be glued to a section of the pencil. The pencil should extend long enough to go through the wall in order to attach the main dial. In my reference pictures, the pencil is green.\nIf done correctly, spinning the end of the pencil, which is attached to one disc, will eventually spin every disc as the teeth meet up. You can now try lining up the notches.\nStep 4: Lever\nThis part is slightly difficult to get right. It takes a lot of trial and error to get the right shape. It is sort of like a more slanted 'L'.", "276" ], [ "Designer: <PERSON>\nPublisher: Alga\nPlayers: 2 – 4\nAges: 6 and up\nTime: Varies\nTimes Played: +30\nGameplay\nI would say Rummikub is easy to play, but really hard to master. To place tiles in the “field”, you will need to make a sum of at least 30 points, once you do it for the first time, you are free to place tiles at your own convenience, regardless of total sum or value. You must create runs of the same color, or with the same number, regardless of color. There are jokers planted that can be use as any value or color. Whoever manages to play all of their tiles effectively becomes the winner of the game. At the beginning of each round, you need to draw a tile from the pile, which adds another piece you can effectively play.\nMy thoughts on the game\nToday, I will be talking about Rummikub, a tile-based game for 2 to 4 players, combining elements of the card game rummy and mahjong.\nI grew up playing this game with my family, especially my grandmother.", "212" ], [ "She was a really a fan of the game. I remember myself at 6 years old already playing it.\nOne of the reasons why I have so much appreciation for Rummikub, it’s because unlike most of the board games I’ve played, this one has a lot of skill and creativity involved. If you become a good thinker and pay attention to the most optimal plays you can do by using your titles, and the ones that are placed in the field (which I forgot to mention before!), your chances of success increase exponentially. Luck is still definitely a factor, but I when you take in consideration other board games such as Ludo or UNO, the difference in skill gap can be huge and way more noticeable.\nThe course of the match can change significantly, in fact, something that occurs often with Rummikub is that it can be an unforgiving type of game. Many times has happened to me that I have a really sequence to play, but I did not play it because I did not realized early that I was able to play it.\nIf you want a board game where skill is super important, I totally recommend you to try Rummikub. It can be frustrating against good players, but progressing and becoming better feels really satisfying.\nI’ll give it a 8.5/10 rating.", "211" ] ]

[ 2438, 6132, 9596, 939, 11289, 342, 1832, 10183, 1732, 4855, 8314, 9223, 2197, 5571, 7496, 8543, 7702, 2616, 7339, 8301, 1045, 2933, 6173, 2963, 7678, 3982, 7117, 8559, 8382, 164, 10557, 3530, 5027, 4306, 2018, 5454, 5263, 1726, 9538, 1075, 9148, 5958, 10402, 9526, 5273, 8832, 1315, 6124, 4393, 2644, 8691, 8705, 11231, 11180, 5006, 344, 10308, 10976, 5440, 7566, 9254, 969, 121, 10699, 10771, 4184, 2959, 855, 9285, 5704 ]

[ [ "The Francophone World’s Uplifting Stories in 2015 · Global Voices\n<PERSON> looks on the bright side of 2015. Image edited by <PERSON>.\nLet's be honest: many of us driven by our hope in humanity would prefer to forget 2015. From January's Charlie Hebdo attacks in Paris to December's attacks in Bamako and the massacres in Burundi, the headlines in the French-language media offered a deluge of armed conflict, epidemics, and hate speech—with some episodes getting more attention than others.\nStill, there were also some remarkable stories of generosity and bravery than were less covered in the media. Global Voices collects a few of the happy events you might have missed while distracted by so much of the gloom in the past year.\nSurviving Ebola in Guinea, Liberia, Mali, and Sierra Leone\nScreen capture of an Ebola survivor testimony.\nThe worst outbreak of the Ebola virus in history claimed nearly 5,000 lives in 2015, with at least 10,000 reported cases mostly in West Africa (Guinea, Liberia, Mali, and Sierra Leone). Besides the terrible impact of human lives lost and the strain on the West African region's healthcare infrastructure, the resulting stigma for the affected population compounds an already dreadful situation. Yet, the epidemic has now been mostly eradicated and the tremendous sacrifice of local healthcare agents is finally recognized. Here is a testimony of their work in Liberia:\n<PERSON>, 30, and two other women, all volunteers, are cooking for 12 of the most important, but invisible, people in Liberia right now. The dozen meals are meant for the team of technicians that tests the blood of suspected Ebola patients. They visit sick peoples’ homes and overwhelmed Ebola treatment centers, sticking needles in the veins of physically unpredictable, highly contagious people. They then drive their blood back to Liberia’s only medical lab, more than an hour from the capital of Monrovia.\nRebuilding the Central African Republic (CAR) Amidst Religious Conflict\n“Christians and Muslims together in a project” to rebuild a mosque in the Central African Republic (CRA). Screenshot: reconstruction of a mosque in the Central African Republic in June 2015 / Dailymotion\nThe conflict in CAR has been below the radar in 2015, even though it has continued to claim victims throughout the country.", "90" ], [ "The fighting between (mostly Muslim) Seleka rebels and (mostly Christian youth group) anti-Balakas has severely weakened the nation's social fabric. Yet, despite the potential threats on their lives, many citizen groups have come together to try to rebuild the country while the confrontations are still ongoing. One such effort is the collaboration between Muslims and Christians to rebuild one of the 417 mosques destroyed during the war (out of a total of 436 mosques registered in CAR). The Centrafrique Blog reports:\nA Bangui, les chrétiens se sont mobilisés pour aider les musulmans centrafricains à retrouver leurs lieux de prières. Au quartier Lakouanga dans le 2ème arrondissement de la capitale, la principale mosquée a ainsi été réhabilitée sur une initiative de <PERSON>, un chrétien du quartier. «Nous avons entrepris cela afin de faciliter la cohésion sociale, de retrouver le vivre ensemble comme à l'époque où chrétiens et musulmans vivaient loin des conflits et en frères. Nous comptons poursuivre cela dans d'autres zones et quartiers notamment au quartier Yapélé où la mosquée a également été réhabilitée avec nos propres moyens»\nIn Bangui, Christians have mobilized to help Muslims find their places of worship. In Lakouanga, a borough in the second district of the capital, the main mosque has been restored thanks to the initiative of <PERSON>, a Christian local resident. “We undertook this in order to facilitate social cohesion, to reclaim the way we lived all together as in the days when Christians and Muslims lived without conflicts and as brothers. We intend to continue this in other areas and neighborhoods, including Yapélé neighborhood where the mosque was also renovated by our own means”\nCaring for Rape Victims in the Democratic Republic of Congo (DRC)\nDespite forecasts saying it would have one of the world's fastest growing economy in 2016, the DRC is still trying to come to terms with the epidemic of rape as a weapon of war that plagues the eastern part of the country.\nWorld-renown Dr. <PERSON> works with victims of sexual violence at Panzi Hospital in Bukavu, the main city in the Kivu region.", "165" ], [ "Madagascar: Debating the Worth of Foreign Direct Investment · Global Voices\nWhile Madagascar attempts to find a way out of a prolonged political crisis, Malagasy bloggers are discussing the value of foreign direct investment (FDI). The worth of foreign investment came into sharp contrast when a land deal with Korean investor Daewoo came under criticism and partly triggered the current crisis.\nMany Malagasy believe that Madagascar, like many other African countries is rich in natural resources but that the land has been plagued by poor governance and unfair trade deals. Ten years ago, The Economist labeled Africa “The Hopeless Continent”. Their most recent publication highlights the rapid growth of many African countries‘ GDP. Still, the growth is not equally felt throughout the continent. In fact, Madagascar is projected to have one of the lowest level of growth in all of Africa.\nAdditionally, the capital city Antananarivo and other cities are currently experiencing frequent running water and power outages that have provoked frustration and outrage [fr] among Malagasy citizens.", "165" ], [ "The current situation is one of the reasons Antananarivo has been ranked as one of the cities with the lowest quality of life in the world by the Mercer’s 2011 quality of living survey.\nHaving been marred in a lengthy political quagmire, the Malagasy blogosphere is trying to steer the debate away from a political solution to an overall debate on how to re-ignite an economy that has faltered over the past three years.\nEvaratra in Madagascar. Photo credit to <PERSON> on the Madagoravox blog\nMaking FDI work for Malagasy people\nLand deals have been discussed at length in Madagascar as a way to get out of poverty; the aborted Daewoo deal was the most publicized case but similar deals have been implemented without much hesitation or reaction.\nThe soundness of deals related to the mineral wealth of Madagascar has been recently debated by Malagasy experts.\n<PERSON> is working at the International Chamber of Commerce and Industry of Madagascar. He voiced his frustration with the current status-quo in the Madagascar political system that according to him is the main roadblock preventing more bilateral cooperation with foreign investors [fr]:\nNous sommes actuellement en cours de création d'une relation commerciale sur le LONG TERME qui sera bénéfique pour les Entreprises de Madagascar entre notre pays Madagascar et le Koweït. L'objectif de cette coopération Étatique serait de mettre en place une ligne de trésorerie (emprunt) de 3 milliards de dollars (voire plus) sur 5 ans avec une mise a disposition immédiate de 1 millard de dollars (encaissement immédiat) que nous pourrions investir dans les activités a forte rentabilité de notre grand pays Madagascar (Activités d'INVESTISSEMENT et non de fonctionnement) [..] .La négociation concernant la mise en place de cette ligne de trésorerie serait la suivante : … 1) Un emprunt de notre État Madagascar a un taux de remboursement a 3,4 %…2) Pret aux Entreprises de Madagascar a un taux de 5,6% ce qui permet de casser le fonctionnement des banques de Madagascar qui prêtent a un taux de 18,20% sur des durées relativement courtes\nWe are currently in the process of building up a long term bilateral trading collaboration between Madagascar and Kuwait that would be beneficial for Malagasy companies. The goal is to set up a loan for three billion dollars over five years with one billion available right away that could be used for high return investment activities (investment and not operational funding). The negotiation is around the following line: 1) Madagascar will be borrowing at an interest rate of 3.4%… 2) the State could loan to Malagasy companies at 5.6% instead of the 18 or 20% rate currently proposed by the national banks on very short term periods.\nIn reaction to his post, <PERSON>, asks in the comment section [fr]:\nPourriez-vous m'expliquer pourquoi vous rêvez devant un emprunt à 3,4% alors que vous n'arrêtez pas de critiquer les institutions de Bretton Woods qui prêtent pourtant à des “taux concessionnels” de 0,5% ?\nWhy are you dreaming of an interest rate at 3,4% when you always criticize the Bretton Woods institutions who loan at 0.5% ?", "165" ], [ "Diaspora and Development in the Francophone World · Global Voices\nThe diaspora of the developing countries worldwide is often mentioned by development experts as a potential driving factor for poverty reduction and the francophone region is no exception. In fact, two conferences are taking places in the upcoming months in Cameroon and Mali about the role of diaspora in supporting development in their respective countries [fr]. Still, the current suggested policies to promote more involvement from the diaspora are not without controversies and require more channels to facilitate collaborations between all development actors (local NGOs, private sector, international agencies and government).\n<PERSON> outlines the goal of the conference in Mali and how they foresee the diaspora contributing to development in Mali [fr]:\nLe Forum Tremplin propose de rencontrer sur leurs stands des entreprises et cabinet de recrutements du Mali, d'Afrique et de France dans les domaines de l'informatique, la banque-assurance, les\nindustries pour le compte d'entreprises (reconnues), en tout 200 emplois (seront disponibles)\nThe Forum Tremplin offers a gathering place for companies and recruiting agencies in Mali, Africa and France in the fields of information technology, banking, insurance and other industries for renowned companies. In total, 200 positions (will be available)\nThe Original African Diaspora by WhiteAfrican- Under CC License\nIn Cameroon, the conference that will take place in Yaounde from August 11-13th 2010, wants to draw inspiration from diaspora from other African nations [fr]:\nSous le thème, “La diaspora camerounaise, un véritable acteur du développement”, il sera question pour les participants, de chercher les voies et moyens pour amener la diaspora camerounaise à s’impliquer davantage dans le processus de développe­ment économique du pays.", "165" ], [ "Pour le MECAM, « à l’instar des pays comme le Mali ou le Sénégal, où l’on sent une réelle implication de la diaspora dans le développement économique, la diaspora ca­merounaise qui apporte déjà beaucoup, le fera davantage dans un cadre réglemen­taire »\nThe theme of the conference is “The Cameroonian diaspora, a true agent of development”. The idea is for all participants to find ways and means to bring the diaspora into committing further in the economic development of the country. According to the MECAM (Ministry of Economy and Commerce): just like in Mali or Senegal, where one can feel a true engagement by the diaspora in the economic development, the Cameroonian diaspora is certainly already bringing a lot to the table, but it would be able to do more within the regulated structure.\nGlobal Net Emigration Map by WorldMapper.org – CC license\nIn Senegal, <PERSON> believes that for the Diaspora to effectively help the country, a focus on education and intellectual exchange to augment the knowledge capital and reach the tipping point towards development is key [fr]:\nTout ce challenge doit se faire dans un environnement propice au progrès et aux débats d’idées en associant les universitaires et chercheurs vivant en Afrique. Il peut s’agir de créer des masses critiques, des regroupements ou des pôles d’excellence pour le décollage de l’Afrique.\nThe challenge is that all of this must happen in an environment that is favorable to progress and to the exchange of ideas and engage scholars and researchers who reside in Africa. It is about reaching a critical mass of centers or hubs with top-notch quality of ideas for Africa to take off.\nIn a presentation on knowledge management in Morocco, <PERSON> stresses out that there are specific know-hows on grid computing and supra-conductivity the Moroccan diaspora have acquired that they should voluntarily offer to share with others back home [fr]:\nfaire appel aux différentes compétences de la diaspora marocaine, pour accomplirdes missions, sur place et /ou à distance, en appui ou dans le cadre des programmes de développement de leur pays d’origine, sur la base du volontariat et d’un engagement déontologique.", "165" ], [ "<PERSON> Is Not <PERSON>, but He Too Has Experienced Persecution as a Journalist in Cameroon · Global Voices\n<PERSON>. Published with his permission\n<PERSON> is not <PERSON>.\nMore than once, however, media outlets have mistakenly identified a photo of <PERSON> as being <PERSON>, a Cameroonian journalist for Radio France International convicted of terrorism-related charges in April 2017 for reporting on the Boko Haram militant group.\nUnfortunately, Global Voices was the latest news organization to make that mistake, and <PERSON> quickly alerted us to that fact. We have since corrected the original article, apologized, and spoken to <PERSON> about his own experience.\nIt turns out that <PERSON> is also a journalist who has faced government pressure on account of his reporting on Boko Haram. Born in Cameroon and trained in Nigeria, he worked for nine years for The News Magazine, one of Nigeria's most iconic political publications. Now he lives in the US capital of Washington, D.C., and is the publisher of Simon Ateba News Africa, which focuses on African events including the political situation in Nigeria, the presidential election imbroglio in Kenya, and Boko Haram massacres in Cameroon.\nIn 2015, after receiving a grant from the Ford Foundation via the International Center for Investigative Reporting in Nigeria, <PERSON> traveled to Cameroon and Chad to report on Nigerian refugees who had fled Boko Haram atrocities in Nigeria. He says he alerted all the relevant authorities beforehand that he would be visiting the area to do journalism.\nHowever, he was arrested in September of that year at the Minawao Refugee Camp in Cameroon's far north and accused of being a Boko Haram spy.\n‘There’s press freedom of Cameroon for those who praise the government’\nWhile in the custody of the Cameroon government, <PERSON> says he was deprived of food and was kept in a cell without any basic amenities. He was eventually rescued from his ordeal with the help of Amnesty International and other human rights organizations.\nHis case highlights the precarious state of human rights and press freedom in Cameroon under the decades-long rule of President <PERSON>. The Cameroonian authorities haven't only targeted individual journalists, but entire populations. For example, earlier this year, following protests over the disparities between Francophone and Anglophone areas, the government shut down Internet access for the country’s English-speaking regions for three months.\n“There’s press freedom of Cameroon for those who praise the government or who do not do serious investigative journalism,” <PERSON> says. “You can insult the President, he may not do anything. But once you begin to meander into serious things such as human rights abuses, financial transactions, and so on, then you are seriously in trouble.”\n“And it's not just the President,” he adds, “the top officers, the cops, everyone is a Lord.", "926" ], [ "Cameroon is more like a police state, a country where there are many laws that are not obeyed or respected by the authorities.”\nThat means practising journalism online is especially risky. <PERSON> doesn't have any illusions about what would happen to him if he were still in Cameroon: “I would be arrested, jailed or killed. Luckily, I have no intention of going there now.”\n‘President <PERSON> does not care about Francophones or Anglophones’\nThe fight against the militant group Boko Haram, which has been wreaking havoc in the country's far north since 2014, has given Cameroonian authorities even more of a pretext to punish journalists who step out of line, says <PERSON>. Under the new anti-terrorism law—the law that was used to convict <PERSON> can just frame anyone. . . .and label the person a terrorist. There is no freedom.”\nBut the truth, <PERSON> argues, is that the narrative in Cameroon has long been skewed. Instead of focusing on the actions of President <PERSON> and his associates “looting everything and destroying the institutions of that country,” problems are often framed as the Anglophone minority versus the Francophone majority.\n“President <PERSON> does not care about Francophones or Anglophones,” <PERSON> says. “Cameroonians are being neglected and being scammed by <PERSON>. If you protest, you oppose him or threaten his power, he comes after you, whether you are a Supreme Court judge or protest leader, whether you are a Francophone or an Anglophone, same treatment.”\nWhat needs to happen, <PERSON> believes, is more cooperation across these divides. “These groups need to unite and remove the gangster and his accomplices and sit down to form a federal country with 10 regions.", "600" ], [ "Making Swahili visible: Identity, language and the internet · Global Voices\nTree roots cling to a 15th-century wall on Kilwa Kisiwani Island, Tanzania. In 1981, the ruins of the powerful Swahili sultanate on the island were declared a UNESCO World Heritage Site. Image by <PERSON>, January 1, 2017, CC BY 2.0.\nEditor’s note: This personal essay was written following a Twitter campaign organized by Global Voices sub-Saharan Africa and Rising Voices where each week, a different language activist shared their perspectives on the intersection of digital rights and African Languages as part of the project, “The identity matrix: Platform regulation of online threats to expression in Africa.”\nAccording to the United Nations Educational Scientific and Cultural Organisation (UNESCO), linguistic and cultural diversity are of strategic importance for people around the world to strengthen the unity and cohesion of societies.\nThis linguistic and cultural diversity propelled the UNESCO general conference to proclaim International Mother Language Day ( IMLD ) in November 1999, to be commemorated annually on February 21 annually. To bolster IMLD, the United Nations (UN) declared the International Year of Indigenous Languages ( IYIL 2019 ), to draw attention to the endangerment of the world’s indigenous languages.\nToday, there are over 7,100 languages spoken around the world, 28 percent of which are spoken on the African continent alone. Despite this, English dominates online spaces in the region. Some twenty years ago, 80 percent of the world’s online content was English-centric.", "696" ], [ "Currently, however, English content online is said to have shrunk to between 51- 55 percent.\n4/4 English\nCan we argue that more people are yearning to get online in their local languages? And is it true that 17 M people worldwide have no reason to get online, https://t.co/owzk24xch4\n— GV SSAfrica (@gvssafrica) May 19, 2020\nThe million-dollar question, therefore, is: Could this sharp drop be an indicator that people now favor their native languages online over English, considering that less than 15 percent of the world population speaks English as their first language ?\nSwahili: Coming to birth?\nSwahili is recognized as one of the official languages ​​of the African Union (AU), alongside English, Portuguese, French, Spanish and Arabic. Swahili is also the lingua franca for East Africa Community (EAC) member states.\nRwanda, an EAC member, saw its lower legislative house approve a law making Swahili an official language in 2017 – in addition to Kinyarwanda, French and English. Besides being used for administrative purposes, Swahili will be incorporated into Rwanda’s school curriculum.\nIn Uganda, the government in September 2019 approved the establishment of the National Swahili Council. Article 6 (2) of the Constitution of Uganda also spells out that “Swahili shall be the second official language in Uganda to be used in such circumstances as Parliament may by law prescribe.”\nIn 2018, South Africa, which boasts 11 official languages, formalized Swahili as an optional subject in its curriculum, starting in 2020. In 2019, the Southern Africa Development Community (SADC) adopted Swahili as its fourth official language.\nSwahili invisibility online\nKaribu Nairobi. Image by <PERSON>, September 20, 2019, (CC BY-ND 2.0)\nDespite Swahili being the most widely spoken African language, with approximately 150 million speakers – mostly in East Africa, the Great Lakes region, southern Somalia, and some parts of Southern Africa, its visibility online is dismal.\n<PERSON>, a lecturer at the Multimedia University of Kenya, states in an op-ed with the Nation, a Kenyan daily, that the absence of online linguistic and cultural diversity creates “a society with a ‘tunnel-vision’ view of the world.”\n<PERSON> predicts that most indigenous cultures end up surrendering “their identities to the ‘English way’ of doing things.” This sad reality can only be reversed if indigenous civilizations “fight to retain their identities both online and offline,” he says.\nJoin our co-founder for a Tweetchat on identity, language and digital rights in Africa starting tomorrow.\nFor Swahili, visit https://t.co/pjjxAsMAva https://t.co/pvHOpbxi6x\n— Centre for Youth Empowerment and Leadership (CYEL) (@cyelke) May 17, 2020\nBut all is not gloom and doom. There are some dedicated organizations at the forefront of promoting and developing Swahili online.", "424" ], [ "How Boko Haram Is Changing International Politics in Western and Central Africa · Global Voices\nAbuja, Nigeria. April 30, 2014. Protesters took to the streets around the three arms zones of Abuja to demand urgent action from the government in finding the 200 school girls kidnapped in Chibok. By <PERSON>. Copyright Demotix.\nTwo suicide attacks on June 22 in Maroua, northern Cameroon, left several people dead and many others wounded. Ten days earlier, 15 people were killed in a suicide bomb attack at a crowded market in N'Djamena, the capital of Chad. The attack came exactly three weeks after a similar bombing claimed the lives of 27 people in the same town.\nBoko Haram, a Sahel-based jihadist group that recently pledged allegiance to ISIS, claims responsibility for the attacks. The group struck again a few weeks after the June attacks, this time in Jos, Nigeria, killing at least 44 people. Boko Haram has repeatedly staged deadly attacks in the Sahel region for the past several years. In response, a coalition of West African countries came together to launch a military counterstrike in the hope of curbing the group's influence.\nBelow is a partial timeline of Boko Haram's offensive in 2015, which spread to Cameroon, Chad, Niger, and Nigeria.\nThe current situation in Cameroon\nAfter months of captivity by suspected Boko Haram militants, ex-hostages arrive at Cameroon's Yaounde Nsimalen International Airport. Public Domain via Wikimedia Commons.\nSince January 1, 2015, Boko Haram has carried out at least 28 major attacks on Cameroonian soil —most of them in the far north region. According to the local authorities in Maroua, the July 22 suicide bombings were carried out by two young girls who were seen begging in the streets in previous days. The explosion killed at least a dozen of people at the central market, but the exact number is still uncertain.", "90" ], [ "A security source confirmed that residents heard a double explosion.\nDespite these tragedies, the Cameroonian military has enjoyed some success against Boko Haram, though the country has also had to deal with the massive afflux of migrants fleeing the conflict.\nThe current situation in Chad\nChad Air Force Sukhoi Su-25 at N'djamena Airport CC-BY-4.0 license. Wikimedia commons.\nThe man who triggered a bomb on July 11 was disguised as a veiled woman to conceal the explosives. In light of this information, the government of Chad has decided to ban the veil to prevent similar attacks. The consequences of the Boko Haram insurgency have massively strained the region's stability, especially in Chad, whose military power was the foundation of peacekeeping in Sahel. In recent months, Chad has already been rocked by student protests and the June 20 start of the trial of former leader <PERSON>.\nThe current situation in Niger\n“Landscape Diffa region Niger” by <PERSON>. CC 2.0 via Wikimedia Commons.\nThe Boko Haram insurgency has forced tens of thousands across the border into Niger's arid southeastern region of Diffa, aggravating an already dire humanitarian crisis. The flood of refugees comes as Niger declares a state of emergency to tackle an insurgency that has brought Diffa's economy to a standstill and left much of the population vulnerable.\nThe current situation in Nigeria\nPrior to the March 2015 elections, the Nigerian Army had considerable gains in repelling Boko Haram. However, a renewed offensive by Boko Haram appears to be underway, ahead of the inauguration of President <PERSON>'s new government. This is despite the fact that one of <PERSON>'s first actions was to move the nation's command headquarters of the military from the capital Abuja to Maiduguri, in Borno State—a hotpot of the Boko Haram insurgency.\nReported explosion in #Gombe, northeast #Nigeria. No further details.\n— <PERSON> (@fidelisMbah) July 22, 2015\nNonetheless, the new government has pushed a great deal for international counterterrorist assistance, as evidenced by President <PERSON>'s recent meetings with the presidents of Chad, Cameroon, and Niger. <PERSON> has sought and received assurances of assistance from the G7 and the United States, where he is currently on a state visit. <PERSON> promised to negotiate with the insurgents, if that would lead to the release of the 200 abducted Chibok girls, kidnapped more than a year ago:\nIf we are convinced that we can have the girls, why not, we can negotiate. Our goal is to have the girls. We will ask them what they want and we can free the girls; return them to their school; unite them with their parents and rehabilitate them, so, they can live a normal life.\nThis post is co-authored by <PERSON>, <PERSON>, and <PERSON>.", "90" ], [ "DR of Congo: How Will the Elections Unfold? · Global Voices\nThe presidential elections in the DRC are scheduled for November 28, 2011. The stakes are evidently high, given the history of civil conflict (the 2006 presidential elections were facilitated by UN peacekeepers).\nThe 2011 campaign officially began on October 28 [fr] and includes 13 candidates in a country that has as many as 400 political parties. Many observers have highlighted the major events during the campaign, and attempted to forecast how the elections will unfold.\nRadio Okapi highlights the difficulties [fr] encountered by the CENI (the Independent Commission for the National Elections) in the days before the elections:\nAu cours d’une conférence de presse tenue vendredi 25 novembre, son rapporteur <PERSON> a déclaré que 33 aéronefs n’ont pas pu décoller pour des raisons météorologiques. Ces engins devraient servir au déploiement du matériel électoral dans les provinces.«Vous êtes un peu déçu, mais rassurez-vous que ce n’est pas de mauvaise foi. C’est pour des raisons opérationnelles », a ajouté <PERSON>.En dépit de ces difficultés logistiques, <PERSON> a annoncé que les élections auront bel et bien lieu le 28 novembre.\nDuring the November 25 press conference, the CENI representative <PERSON> declared that 33 aircraft could not take off because of bad weather. The planes are needed for the distribution of election materials in the provinces. “You're a little disappointed, but rest assured that it's not in bad faith. The delay is mostly because of operational reasons,” said <PERSON>. Despite these logistical difficulties, <PERSON> announced that elections will indeed take place on November 28.\nRadio Okapi also notes that 50,000 voters in the region of Rutshuru of Northern Kivu still did not know where they would vote [fr]:\nDes sources rapportent qu’au moins 18 centres n’ont toujours pas de listes d’électeurs. Cette situation inquiète les électeurs de ce territoire.", "575" ], [ "[..] Député élu de la circonscription électorale de Rutshuru, <PERSON> appelle ses électeurs à l’apaisement.\n«J’ai contacté la haute hiérarchie de la Ceni. Toutes ces autorités viennent de me rassurer que les listes électorales vont nous arriver avant les élections. Tout détenteur de la carte électorale à Rutshuru va voter lundi. C’est la garantie qu’ils m’ont donné et je voudrais que toute la population de Rutshuru s’apaise», a rassuré le professeur <PERSON>.\nSources report that at least 18 centers still do not have electoral lists. This worried the voters of the territory. […] <PERSON>, the elected MP in the electoral district of Rutshuru, asked her constituents for calm.\n“I contacted the top hierarchy of the CENI. The authorities assured me that the voters lists are going to reach us before the elections. Any holder of a voter's card in Rutshuru will be able to vote on Monday. This is the guarantee they gave me and I want all the people of Rutshuru to stay calm.”\nVoting Booth in DRC on Flickr by FredR (CC BY-NC-ND 2.0).\nIn Bunyakiri, the blog Local Voices also raised concerns about the fact that electoral lists and voting ballots are still to be dispatched [fr] to 160 polling stations.\n<PERSON> sums up the growing fear of delay:\nA last-minute delay in the election appears to be likely, according to several separate diplomatic sources in Kinshasa. The sources, who wished the remain anonymous given the insistence by the election commission that elections will be held on November 28, said that it would extremely difficult to deploy all necessary materials on time. However, one of the diplomats suggested that the commission thinks it will be less controversial to present the various actors with a fait accompli: a brief delay of the polls.\nHowever, other sources, including the election commission and the UN peacekeeping mission, believe it is still possible to hold elections on time.\nThe logistical task for the election commission is daunting.", "847" ], [ "COVID-19: Switching online is not an option in conflict-stricken countries in the Middle East · Global Voices\nStreet scene in Sana'a, Yemen, where the majority of those with internet access are young men, April 28, 2015. Photo by <PERSON> via Flickr by CC BY-SA 2.0.\nThe COVID-19 pandemic has forced governments across the world to impose lockdowns, sending billions of people into home confinement. This exceptional situation has caused a lifestyle paradigm shift.\nWorking, learning and socializing online has become the norm, as people severely restrict their time outside to limit any prospects of catching the novel coronavirus.\nThe use of the internet is not new, but COVID-19 fast-forwarded this global shift where the internet dominates all aspects of life for those who have access to it.\nIf online is the way forward in these times of a pandemic, what about countries stricken by conflicts with limited internet access?\nCOVID-19 accelerates digital transformation\nThe COVID-19 pandemic and the unprecedented measures taken to stop its spread have changed our lives. It has led to fundamental shifts in how societies and businesses operate.\nAs the deadly virus disrupts the world and may continue to do so until a vaccine is discovered, the internet has taken over. Studies show that internet traffic has surged by between 50 percent and 70 percent since COVID-19 began.\nTrapped at home, people turned to the internet en masse to continue their daily routines including shopping, working and learning, communicating and socializing. This will likely have a lasting impact well after the pandemic ends.\nA deepening digital divide\nThe internet is widely available and provides a lifeline in wealthy countries during COVID-19, but this is not the case for almost half of the world’s population, which has no internet access . The majority of this population lives in poor, war-stricken countries where infrastructure is failing and yet, the need for information is most urgent.\nIn conflict-stricken countries, many citizens face this additional crisis without the internet. Meanwhile, in wealthy, peaceful countries, the internet has enabled citizens to mitigate the impact of lockdowns by allowing them to continue to work, study, communicate, socialize and access information.\nIn some countries in the Middle East and North Africa (MENA), COVID-19 struck at a time of economic crisis, and wide-scale conflict or uprisings. Years of conflict in Yemen, Syria, and Libya have brought immense suffering, displacement and destruction.", "803" ], [ "Infrastructure has been targeted by warring parties with disregard for civilian life.\nIn Syria, for example, over 50 percent of the infrastructure is no longer operational .\nIn Libya, much of the telecom infrastructure has been destroyed or stolen, including about a quarter of the country’s mobile tower sites. As a result, basic services — electricity, sanitation, water and the internet —have been brought to a standstill.\nIn Yemen, labeled by Relief Web as the world's worst humanitarian crisis, internet access is a major obstacle. Only about 27 percent of Yemenis , mainly young men located in urban areas, have internet access.\nThe majority of youth are striving to find ways to connect to the external world. “The internet is our oxygen and is as important as food. I moved from my town to the capital to be able to connect,” said <PERSON>, a Yemeni journalist who asked Global Voices only to use his first name.\nWomen in the region are disproportionally affected by this digital divide. Fewer women have access to the internet than men, which reflects a regional gender inequality gap with Yemen, Syria and Libya ranking near the bottom of all countries.\nA combination of conservative social norms, less access to learning and financial resources and a hostile online environment impede women’s ability to connect and access information online and minimizes participation in online discussions.\nThe internet: High cost, low speed and unreliable\nIn Libya, Syria and Yemen, strained by conflict and economic chaos, users face low-speed internet and prohibitive costs.\nYemen has the slowest internet speed globally with an average speed of just 0.38 megabits per second in 2019: It would take over 30 hours to download a 5-gigabyte film. In January 2020, damage to a submarine cable plunged Yemen into an internet outage for over a month.\nThe COVID-19 pandemic has forced massive school closures , affecting 90 percent of the world's student population, which has led to a culture of virtual learning, online education, but learning proves nearly impossible without a reliable, high-speed internet connection.\nThis also prevents people from communicating and journalists from reporting and reaching a large audience . L ow speeds make it difficult to browse, download or upload materials and communicate with sources. It also deprives access to valuable resources critical to writing reports, news stories and daily events.", "803" ] ]

[ 3776, 9599, 8251, 6802, 9122, 10191, 5427, 304, 10683, 2791, 3743, 10153, 5873, 7200, 9861, 10458, 6667, 5212, 10596, 7736, 6296, 272, 8852, 5111, 5256, 7650, 9672, 6370, 620, 2338, 10654, 872, 2730, 10256, 9151, 2722, 3067, 6299, 8403, 6078, 2492, 9170, 6378, 3028, 10271, 8428, 1470, 2993, 3186, 5073, 7404, 3965, 6842, 6506, 3291, 8854, 6890, 5842, 9524, 10026, 3981, 4967, 6269, 5317, 6443, 7967, 1191, 8476, 9034, 2300 ]

[ [ "Walnut Standing Desk | Hidden Inductive Charger\nIntroduction: Walnut Standing Desk | Hidden Inductive Charger\nwww.howidothingsdiy.com\nI finally built myself a proper walnut desk with a power base! Here's my walnut standing desk build! I can't believe this is my desk. This is my dream desk I've always wanted to build. I locally sourced some beautiful walnut wood and a motorized base so I could have a standing desk or sitting desk in my office. I even included a hidden drawer, hidden inductive phone charger and finished it with Odie's oil!\nFollow my video and build yourself your dream desk and let me know how it goes!\nHere is my Instructables to make the drawer https://www.instructables.com/How-to-Make-Drawer-B...\nMain Features\n-Power base https://amzn.to/3BxWXFU\n-Hidden inductive charger (phone charger)\n-Beveled skirt\n-Hidden drawer\nSupplies\n-Wood of your choice\n-Power base\n-Inductive charger\nStep 1: Design/materials\nI designed my concept in Fusion 360 3D CAD software. I made sure to consider all the features I wanted like a drawer, PC holder, inductive phone charger and power base. Then sourced my lumber from a local hardwood store.\nStep 2: Cutting Boards to Size for Top\nNext I determined the final size of the top and then figured out how wide each of the boards would need to be to get that final width. Then I cut them all to an equal width and about 2\" longer than the final length so I could cut the ends even after its glued up.\nStep 3: Gluing Up the Top\nThen I applied wood glue on all the edges and clamped with even pressure. I used cauls to keep the top even when clamping but you could also used biscuit joints, dowels or biscuits to aid in alignment. I let the glue up dry for about 3 hours and then unclamped.\nStep 4: Planing and Sanding the Top\nThen to ensure the top was as flat as possible, I used my power hand planer to plane the top until the joints between boards were smooth. Then I rough sanded with the belt sander with a 60 grit belt. Finally, I sanded with my orbital sander working my way from 80-120 grit sandpaper.\nStep 5: Cutting Ends and Routered Edge\nI used an edge guide and a circular saw to cut the ends off. I made sure my cut was perpendicular to the long edges, straight and also cutting it to the final length.", "401" ], [ "I then added a nice chamfered edge with my router to make the table look nice and be more comfortable to use.\nStep 6: Assembling the Base\nI took a break from the heat and sawdust and assembled the power base using the manufacturers instructions. I needed this installed to determine the final dimensions of the drawer and the length slides I needed to order.\nStep 7: Inductive Phone Charger\nWith the base laid on the top I marked all the mounting holes and the skirt location so I could see where the inductive charger could fit. I then marked that location and drilled a small hole at the center of the charger to mark the location on the top. Then I flipped the top over and taped the charging symbol I printed out over the hole I just drilled. Then I carved out the symbol with a sharp box cutter and squared off the edged with a sharp chisel. Then I filled with black CA glue and sanded flush with the wood surface.\nNext I determined how thick the top could be and still allow the phone to charge through the top. I did this by using playing cards as spacers and then measured the final thickness of the stack of cards.\nNow that I new the final thickness, I made a quick router pattern and used blue tape and CA glue to glue it in place. Then I used a pattern bit in my router to cut out the circle to the right depth. Finally, I cut a slot in the table to route the charger wire.\nAfter testing to make sure my phone charged, I used hot glue to secure the charger in place.\nStep 8: Building the Skirt\nI wanted my skirt to be beveled, so I cut a 30 degree bevel cut on each long edge. The bevel cuts should be parallel to each other as shown. Then I made 30 degree nailing blocks to attach the skirt to and glued them to the top with wood and CA glue. Next I cut the skirt sections to length with 45 degree miter cuts in the corners using my crown molding jig.\nThen I preassembled the corners with wood glue, CA glue and tape. After the glue was dry, I nailed the skirt onto the nailing blocks.", "996" ], [ "How to Make Drawer Boxes | With a Beveled Face\nIntroduction: How to Make Drawer Boxes | With a Beveled Face\nwww.howidothingsdiy.com\nIn this woodworking video I'm going to show you how to make drawer boxes with a floating bottom and how to install them. This drawer is a little special as it has a beveled front face. I'll walk you through all the steps to build this walnut drawer box with a floating bottom. I'll show you how to install drawer slides and make adjustments. I'll even show you a trick to install the drawer face.\nThis drawer build is part of building a walnut office desk. Please also check out the rest of the build on my channel.\nSupplies\n-Drawer slides\n-3/4\" Wood for frame\n-Wood glue\n-Brad nailer\n-1/4\" plywood for floating bottom\n-Scrap 3/4\" plywood for nailiers\n-1/2\" plywood for supports\nStep 1: Install Supports to Attach Slides\nFirst measure your space and select and purchase right slides. If the area you want to install your drawer into doesn't have anything to attach slides to, add some supports to screw to. I used 1/2\" plywood for the supports and 3/4\" plywood to make some mounting blocks to nail to. I used CA glue to immediately hold the piece in place while I nailed it but also regular wood glue to hold the support in place long term. Then I glued and nailed some 3/4\" support blocks in place for added strength.\nStep 2: Measure and Cut Frame\nMeasure your space for the drawer between the supports to determine how big your drawer box can be. Just remember that typical drawer slides are about 1/2\" wide on both sides and that you will need to attach a face to the front of the drawer. Now cut the sides, front and back. I'm using 3/8\" rabbets in the side pieces so I added 3/4\" to the front and back. Remember, you want to build the frame with the front and back inside of the side pieces so only the sides are visible when the drawer is done. You do not what to have end grain showing.\nStep 3: Cut Floating Bottom Slot in Frame\nCut a slot about 1/4\" from the bottom of each of the frame pieces. Not find a scrap piece of wood and do the same.", "401" ], [ "Now move the fence enough to make a slot just wide enough for the drawer bottom and try it on the scrap piece. You should be able to slide the drawer bottom in the slot but it should fit snug enough that it wont rattle. Once your happy with your test piece, cut all of your frame pieces the same way.\nStep 4: Cut Rabbets in Side Frame Pieces\nUsing either a dado set or multiple passed with a flat kerf blade, make your desired rabbet cut so the front and back frame pieces fit into the sides. Again, I made my rabbets 3/8\" deep and as wide as the material I was using.\nStep 5: Assembly/Cut Bottom to Size\nAssemble the back and side pieces using the rabbet cuts, glue and brad nails. Measure and cut the bottom to fit into the slots with about 1/8\" of allowable movement. Now slide the bottom into the frame and then install the front frame piece using the rabbet cuts, glue and brad nails. Fill the holes and rough sand the assembly. You will be sanding it again later.\nStep 6: Install Slides\nTypically side mounted slides will be mounted near or at the bottom of the box. But in this example I mounted them near the top because of the beveled front face. I attached the slides to the drawer box first and then measured where the mounting holes needed to be in the supports on the desk. Then I predrill holes and installed the slides in the desk, making sure that they were level. Then, test fit the drawer box into the the space and make sure it slides smoothly. We will make final adjustments later.\nNote: If the drawer is a little tight you can plane or sand down the side faces a little bit to get the drawer to slide smoother.\nStep 7: Sand/finish\nMake sure all the holes are filled and then sand working your way from 60-240 grit sand paper. Finish with your finish of choice.\nStep 8: Install Face\nUsing double sided tape, stick the face in place where you want it. I added recessed holes for the face screws on the inside, but it is not necessary. Screw the face on from the back side making sure the screws you selected will not go through the front of the face. Now remove the drawer and double sided tape and reinstall using the screw reference holes you just made.", "785" ], [ "Custom Tool Wall Organizer | Router and Drill Station\nIntroduction: Custom Tool Wall Organizer | Router and Drill Station\nwww.howidothingsdiy.com\nIn this video I’ll show you how to make a custom tool wall organizer for your routers, drills and bits. This router and drill station will greatly improve shop organization and improve efficiency.\nI’ll start by creating a layout of all the tools I want in my organizer. Then I’ll mark out where the separators will go. Then I’ll use my table saw to cut the frame pieces. Next I’ll build the frame and cut a rabbet in the back so the backer sits flush. Install the backer panel, then cut and install the separators. Tool holders are needed, so I will cut and install those next. Finally, install the magnetic tool holders and hang the organizer on the wall.\nPleas SUBSCRIBE to my YouTube channel for more great how-to videos!\nSupplies\n1/4\" plywood\n1x4 Pine Boards\n1x6 Pine Boards\nScrews\n<PERSON> nails\nWood Glue\nCA Glue\nStep 1: Layout\nI laid everything out where I want it. For all of my various bits I'm going to use these magnetic strips to make it super easy to grab something when I need it.\nI'm laying out the drills on their side so they stay tighter against the wall.\nI'll put batteries on top and hang the charger on the wall.\nStep 2: Build Frame\nNow I'm going to determine the overall size and build the outer frame.", "493" ], [ "For ease and cost, I’m going to try to keep it all smaller than a piece of ¼” 2x4 handi plank.\nFirst determine where the tools will be and figure out where to put separators.\nThen, measure your layout and cut the frame pieces to size. For the frame I’m using 1x6.\nI’m cutting a rabbet in the back so the ¼” panel sits recessed and allows the frame to sit flush against the wall.\nStep 3: Make & Install Back Panel\nCut the ¼” backer panel to size. I went with a design that uses a frame for strength and then I'll just add a ¼\" backer to tie it all together. Then I’ll add some support strips that will allow me to attach the magnetic bit holders.\nAttach the backer panel to the frame using glue and nails\nStep 4: Install Separators\nNow I separated things out a bit and to added more strength by putting boards in as separators.\nI ripped the separators down to about a 1x5.\nUsing your marks on the backer board, drill guide holes for your screws.\nNow screw the separators in place\nStep 5: Install Tool Holders\nDetermine where the tools will go and make and install some hangers.\nFirst I measured, cut and ripped all of the tool holders to size and then test fit.\nUsing a jigsaw, I cut out slots to hold the drills and routers.\nPlace the tools in the holders and mark the location for each tool holder. Make sure the holders are square before making your marks.\nNow, using your marks, drill guide holes for the screws.\nUse brad nails to secure the holders from the sides and screws in the back.\nStep 6: Install Magnetic Bit Holders\nWith all your bits installed, determine the best spacing for your magnetic bit holders and mark their locations.\nI cut strips of ½” plywood to screw the magnetic strips to. I used CA glue to temporarily hold them in place while I drilled guide holes and then screwed them on from the back.\nThen I drilled holes for the screws and screwed the strips in place.\nStep 7: Hang Organizer on Wall\nFinally, find the wall studs and make a level line on the wall. Now install a strip of wood to support most of the weight of the organizer. Now add 4-6 3” screws with washers to secure the organizer to the wall. Be sure to put these screw near the frame.\nEnjoy a more organized shop and better productivity!", "56" ], [ "Creating a Custom Desk Top With Hidden Phone Charger\nIntroduction: Creating a Custom Desk Top With Hidden Phone Charger\nHey guys! In this Instructable I’ll show you how I created my own custom desk top from walnut and added hidden wireless phone charging!\nKeep reading and I’ll show you how I did it!\nIf you like this instructable be sure to check out my most popular instructables below:\n5 Pro Tips for Making Cutting Boards\nHow to Make an End Grain Butcher Block\nHow to Make a Slab Flattening Mill\nThe Ultimate Table Saw Fence\nIf you like this instructional content you can also find me at:\nMy Website (full tutorials, plans, videos): https://mwawoodworks.com\nMy YouTube (all my build videos): https://youtube.com/c/mwawoodworks\nMy Instagram (behind the scenes stuff): https://instagram.com/mwawoodworks\nMy Pinterest (things I find inspirational) : https://pinterest.com/mwawoodworks\nSupplies\n►Rubio Monocoat Pure - https://amzn.to/3kRzXtO\n►Wireless Charger - https://www.mockett.com/power-communication-syste...\n►Titebond 2 Wood Glue (bottle) -https://amzn.to/3sTAjD8\n►Condiment Bottles (for glue) - https://www.mockett.com/power-communication-syste...\n►Parallel Clamps - https://www.mockett.com/power-communication-syste...\n►Scraper - https://www.mockett.com/power-communication-syste...\n►GOOD cedar pencils (trust me) - https://www.mockett.com/power-communication-syste...\n►Dewalt Trim Router (bare tool)- https://www.mockett.com/power-communication-syste...\n►45 degree chamfer bit (underbevel)- https://www.mockett.com/power-communication-syste...\n►Freud Heavy Duty Ripping Blade (for table saw) - https://www.mockett.com/power-communication-syste...\nStep 1: Milling the Rough Walnut Lumber\nI’m making my desk top out of 6/4 walnut and I begin by breaking this lumber to rough length at the miter saw. I want the final length of the desk to be 5 feet so I’m cutting these to about 62 inches for now.\nSince I purchased rough sawn lumber, I needed to mil up these boards. But I did want to mention that if you don’t have a jointer or planer you do have the option of buying pre-surfaced lumber and skip the milling process entirely. Because a couple of these boards were wider than my jointer, I needed to trim them down to be able to mill them.\nOver at the jointer I began to flatten one face of the boards. After that I flipped them on edge to make one edge square to the newly flat face.\nNow that I have a flat reference surface I head next door to the planer to make the opposite face parallel to it.\nOnce the planing is done I could rip the last edge straight at the table saw.\nAnd that’s basically it, these boards are ready for the first glue-up.\nStep 2: Initial Glue-up\nSo, before I do this first glueup I want to mark the middle joint so I don’t accidentally glue it together.", "493" ], [ "These white markers from RevMark are fantastic for working with walnut. So much easier to see these marks.\nThen I just add some glue and spread it evenly across the joints. I only glue one side of the joint, otherwise you just get a bunch of squeeze out and a big mess.\nI do my best to make sure these joints line up flush. Its not super critical because I will be running these through the planer but the flatter they are the less material you need to remove and I want to stay as close to and inch and a half as possible on the thickness of this desk top.\nI then alternate my clamps top and bottom to get good even clamping pressure. After about 30 minutes I went back and scraped off the excess glue. It’s a lot easier to remove it now once it’s skinned over and begun to solidify.\nIts also a good idea to remove the glue so it doesn’t interfere with how flat these are as they go through the planer.", "933" ], [ "How to Make a Minimalist Desk - Work From Home Set Up\nIntroduction: How to Make a Minimalist Desk - Work From Home Set Up\nMore and more people are choosing to work from home or at least taking up some form of hybrid working. Having a dedicated workspace makes a huge difference to productivity, so in this article I'll show you step by step how to make your own minimalist desk for a great work from home set up.\nYou can watch the how to video here:\nhttps://youtu.be/u2Tm9WFlmDU\nSupplies\nMaterials Used:\n* Oak Kitchen Worktop\n* Steel Legs\n* Rubio Monocoat Oil\n* M8 Machine Screws\n* M8 Threaded Inserts\n* Spray Paint\n* Resin\nTools Used:\n* Dewalt Track Saw\n* Trend Sheet Sander\n* Trend Orbital Sander\n* Trend 18V Drill\n* Makita Countersink Set\n* Hand Saw\nStep 1: Cut the Wooden Desk Top to Size\nFor the top to my desk I opted to use a piece of solid oak kitchen worktop. A full 3 meter long worktop is rough £300/400 brand new but I managed to find a bargain on Facebook marketplace. A Full 3 meter long, 60cm wide, 38mm thick solid oak worktop for £90. I was over the moon with that price! I rough cut it so I could fit it into my car so the first step in this project is to cut the rough edge to its final length.\nI cut the top of my desk to 1 meter long. You can of course adapt the size to suite your space and needs. I made the cut using a track saw. This makes quick work of the cut but you can also use a regular circular saw and a straight edge too. Or of course use a handsaw for a proper workout.\nStep 2: Cut Underbevels\nI wanted to keep the full 60cm depth to the desk but I did think adding an under bevel to the sides would be a nice touch. So I tilted my track saw to 47 degrees. I then overhung the track by 1cm from the edge I wanted to cut. This will result in a small right angle transition into the 47 degree angle. It's a small detail but I think it makes all the difference.\nI made this cut to the front and two side edges of the desk. I left the back square as it would be against the wall. My track saw didn't make it through the full the thickness of the angled cut so I finished off the cuts with a hand saw.\nStep 3: Sand & Fill Voids\nThe angled cuts did have a few burn marks on them so I sanded the angle smooth to remove the marks and ease the edges slightly. I used a 3/4 Sheet Sander to do this. I had a few voids that needed to be filled so I used some epoxy resin mixed with black pigment to do this.", "787" ], [ "Once the resin was dry I could sand it flush. I used an orbital sander to sand the top all over to 240 grit. I wanted to make sure it was nice and smooth ready for the oil stain finish.\nStep 4: Oil & Stain Wooden Desk Top\nFor the finish I tested a few colour but I landed on using the Chocolate colour Oil Plus 2C from Rubio Monocoat. I applied a liberal coat all over the top and left it to soak in for a few minutes. I then wiped away the excess and left it to dry overnight. Once dry, I buffed it smooth with a clean rag.\nStep 5: Prep Desk Legs\nI did have plans to weld my own legs for this project but when I found I could buy them cheaper then I opted to do that instead. I picket up these legs from Hartleys Direct.\nOnly the clear coat legs were in stock so I sprayed mine matt black. I gave them 2 coats sanded with 240 grit sandpaper between coats. I did also need to make the predrilled holes larger so I drilled them out to 8mm. This will allow the machine screws to fit through later. I also used a 16.5mm counter sink so that the heads to machine screws would sit flush to the surface of the steel.\nStep 6: Add Mounting Hardware\nIt's time to add the mounting hardware to the desk now. I first lay the legs onto the underside of the desk top, made sure they were square and marked the holes with a pencil. I then drilled 12mm holes into the table top where I had marked.\nThese holes are to receive M8 threaded inserts. These inserts will allows the table legs to be attached with M8 machine screws later. They get drove into place using the included allen key.\nRather than keeping the M8 machine screws plain. I decided to add a pop of colour by spraying them Magenta. Yes, it's magenta.", "959" ], [ "Pi Pie Stand\nIntroduction: Pi Pie Stand\nTo celebrate Pi Day I decided nothing would be better than making a pun! So, I made a Pi stand. I feel like people who are quirky enough to celebrate their love of pie and Pi would get a kick out of this unique twist on the traditional cake stand, and the added strip of walnut inlay gives this Pi stand enough character to make it stand out beneath the pie its holding.\nSupplies\nMaterials needed:\nFor the Pi piece\n10 inch long x 6 inch wide x 2 inch thick Piece of Maple ( I used maple because it was what I had on had)\nFor the round plates\nTop Plate: 14 Inch long x 10 1/2 wide x 1 inch thick Piece of Maple ( the top and bottom plate will be cut from the same piece of maple)\nBottom Plate: 12 Inch long x 7 inch wide x 1 inch thick Piece of Maple\nWalnut Inlay: 10 inch long x 2 inch wide x 1 inch thick ( you will cut you inlays from this one piece)\nTools Needed:\n* 220 grit sand paper\n* 150 grit sand paper\n* Metal Files\n* Wood glue\n* Nail Gun\n* 1 1/4 Brad Nails\n* Band Saw\n* Jointer\n* Planer\n* Table Saw\n* Disc Sander\n* Circular Saw\n* Clamps\n* Pencil Compass\n* String\n* Tape Measure\n* Pencil\n* Oil/Stain/Paint\nStep 1: Cutting Walnut\nFirst ALWAYS REMEMBER SAFETY FIRST! PLEASE WEAR PROPER EYE AND EAR PROTECTION WHEN WORKING WITH DANGEROUS TOOLS!\nTOOLS NEEDED:\n* Band saw\n* Tap measure\n* pencil\nFor this project I used rough cut wood, this will come up later as it will need to be jointed and planed, but first we need to make our cuts!\nWe will need to cut our walnut for the inlay. The three pieces of inlay will all be cut from the same piece of walnut, I only had a 10 inch piece so that was the max that I could do, but for this project that is perfect.\nCutting Initial Piece\nI used my band saw with the fence as a guide to cut all my pieces to the desired width. Before cutting make sure to mark your wood with all the correct measurements.\nCut a piece of walnut down to a strip to 10 L x 2 W x 1 thick. I drew a diagram of this in the pictures for reference.\nCutting Pi Piece\nNext is cutting the Pi piece.", "415" ], [ "Once again I adjusted the fence on my bandsaw to help me cut a strip off that measured\n10 inch L x 2 inch W x 1/4 inch thick. As stated above, I drew a diagram for reference.\nCutting Plate Pieces\nFinally, time to cut the strips for the top bottom and middle pieces. Take the leftover walnut and use it to cut the final two strips for your two plates.\nFor the bottom plate:\nFirst cut a strip 10 inch L x 1 inch W x 1/4 inch thick\nFor the top plate:\ncut a strip 10in L x 1 W x 1/4 inch thick\nYay! You have now cut your inlays!\nStep 2: Cutting Maple\nTOOLS NEEDED:\n* Table saw\n* Circular saw\n* Tape Measure\n* Pencil\nNow for this step we will be cutting the maple for the top and bottom plate and for the Pi shape. The top and bottom plates are fairly easy and straight forward since the wood is already the desired thickness of 1 inch so they only need to be cut to length x width.\nTop & Bottom Plate\nFor this cut I used a circular saw because my board was pretty long and it was easier to maneuver the circular saw than maneuver the board around. I clamped the board to my work table and made sure that I had my eye and ear protection on and made first my top cut of\n14 in L x 10 1/2 in W x 1 in thick\nAfter this cut, I made my bottom plate cut to\n12 in L x 7 in W x 1 in thick\nYou can use any method you like to cut your wood to your dimensions, such as a compound miter saw, hand saw, or table saw, like I said I just used my circular saw for ease.\nPi Piece\nSometimes things work out well in life and it turns out I already had a piece of maple that was perfectly sized for this project, so I did not need to cut this piece. However, I do know the wood fairies do not visit everyone and bestow perfect pieces of cut wood in their garages so they may need to cut their own.", "76" ], [ "Ultimate Router Station\nIntroduction: Ultimate Router Station\nHey guys! In this Instructable I’ll show you how I added tons of storage space to my router table to create the ultimate router station! I added enough room to store over 100 bits as well as quick access to commonly used tools as well a big storage drawers for router and accessories. Basically everything I own for my routers in one place!\nKeep reading and I’ll show you how I did it!\nIf you like this instructable be sure to check out my most popular instructables below:\n5 Pro Tips for Making Cutting Boards\nHow to Make an End Grain Butcher Block\nHow to Make a Slab Flattening Mill\nThe Ultimate Table Saw Fence\nIf you like this instructional content you can also find me at:\nMy Website (full tutorials, plans, videos): https://mwawoodworks.com\nMy YouTube (all my build videos): https://youtube.com/c/mwawoodworks\nMy Instagram (behind the scenes stuff): https://instagram.com/mwawoodworks\nMy Pinterest (things I find inspirational) : https://pinterest.com/mwawoodworks\nSupplies\nTOOLS AND SUPPLIES IN THIS PROJECT:\n►2-Sided Tape - https://amzn.to/3yha6ly\n►True Position Drawer Hardware Jig - https://amzn.to/3ePbWSJ\n►Mag Switch - https://amzn.to/3ePbWSJ\n►18\" Drawer Slides - https://amzn.to/3ePbWSJ\n►1/4\" router bit for locking rabbet joint - https://amzn.to/3ePbWSJ\n►Black Edge Banding - https://amzn.to/3ePbWSJ\n►Power Switch with Paddle - https://amzn.to/3ePbWSJ\nStep 1: Final Pics and Tour\nI was able to squeeze just about every square inch of storage space I could get out of my Woodpecker router table. I added a HUGE bottom drawer for storing handheld my handheld routers and accessories.\nThere's a 4\" drawer just below the router dust box for my coping sled and larger router bit sets.\nOn the right, I added a small drawer to hold my most used tools (collet wrenches, plate inserts and router lift tool)\nAnd finally I added this awesome slide out bit storage that has room for 100+ router bits in 1/2\" and 1/4\" shank sizes.\nEverything I own related to routers can be stored in this router station! Score +1 for shop organization!\nStep 2: Prepping for the Build (really, Deciding What I Want to Do LOL)\nOne thing I need to do before I get started is measure how much room I have under the dust box. I want to squeeze in a shallow drawer here to really maximize the storage space in this cabinet. I also measure for my side panels and the bottom drawer as well.\nAnd now I can remove the dust box to get it out of the way.\nI also need to drill a few screw holes to help me mount the panels.\nOnce all that is done I can begin cutting my cabinet parts.\nStep 3: Cutting the Side Panels\nSince the top and rails of the router table are black I wanted to find a way to make the whole cabinet black. At first I considered painting plywood because I really didn’t want to use black melamine. I’m really not a fan of particle board, but then I found something I’d never seen before at my local plywood dealer.\nIt’s called shelf liner and its got a melamine like coating on top of a plywood core.", "493" ], [ "This fits exactly with what I was thinking for this project.\nThe first step here is to cut the side panels of the cabinet and doing this at the MFT is pretty simple. I need four panels total.\nThe only other thing I need to do to these is cut notches on two corners and these allow space for the bolts that connect the frame of the router table. To do this I like to set up a mag switch to act as a positive stop. I just set the fence into position and I can knock these cuts out fast and each one is the same. To get the short side of the notch I just reposition the fence and the magnet and keep on cutting.\nStep 4: Installing the Side Panels\nThese fit in really nice with those notches cut out. I cut the back\npanels out of ½” ply. And for the top panel I needed to make an access for the dust collection as well as some air vents for the router.", "599" ], [ "DIY Wood Towel Holder\nIntroduction: DIY Wood Towel Holder\nIn this woodworking video I'll be showing you how to make a DIY wood towel holder with case miter joints! This custom towel holder holds up to 5 towels. I used Fusion 360 3D CAD software to design the towel holder. This also allowed me to figure out my miter joints. If you just used brad nails instead of case miter joints, its a relatively easy woodworking project and can be done with minimal tools. I however got a little more fancy and used case miter joints (spline miter joints) made from hard maple. The main towel holder is made from walnut wood. I mostly used my miter saw, my DeWalt table saw (DWE7491RS) and my Ridgid orbital sander. Finally, I finished the towel holder with Mr <PERSON>'s Super Duper Everlasting Oil.\nMain Features\n-Walnut wood\n-Case miter joints with maple splines\n-Holds up to 5 towels\nDownloadable plans ($4.99)-https://howidothingsdiy.com/printable-pdf-plans/ol...\nSupplies\n-1 1/2\" x 1 1/2\" wood\n-Scrap contrasting wood for splines (optional)\n-Wood glue\n-Mr Cornwalls Super Duper Everlasting Oil (Or any other finish you like)\n-Brad nails\n-Table saw\n-Miter saw\n-Sander\nStep 1: Design\nImportant: Before doing anything, watch the reference video in its entirety. It will give you a very good understanding of the project before you start.\nWhen you're ready to start, buy however many towels you want and roll them up like you would when they are in the holder. Then measure the length and diameter. Now, design the towel holder using either 3D CAD software or a sketch. I've included an image of the rough dimensions of my towel holder that holds 5 bath towels.\nStep 2: Cut Pieces to Rough Size & Fill Holes/Knots\nNow cut all the pieces in the miter saw to about 1/4\" longer than the final length. This is a good time to fill any knots or holes. Then, run them through your table saw to get your final profile size. This milling operation also cleans up the workpiece. In this case I was using a 1 1/2\" thick board that I ripped down to be 1 1/2\" thick.\nStep 3: Cut Miter Cuts\nNow cut the 45 degree miter cuts in the direction you came up with in your plans. Be sure to check that your saw is cutting a nice 45 degree angle before making your cuts.", "493" ], [ "It's a good idea to lay out the pieces as you're going to make sure everything looks right.\nStep 4: Make Case Miter Joints (Optional)\nThis is an optional step. If you choose not to do this, you can assemble using wood glue and brad nails.\nIf you choose to use case miter joints, then the first step is to rip down the spline material to about 1/4\". You can make it thicker or thinner. It is your preference. Measure how thick your spline material is and then cut the slot into the miter as shown. This will be done in 2 cuts with the blade set perpendicular to the miter face at 45 degrees. You will cut all pieces with this set up. Then adjust your fence and blade depth to make the slot wider. I highly suggest practicing on a some test pieces. The reference video should be very helpful for this part.\nStep 5: Assembly\nIf you're using brad nails, assemble using wood glue and brad nails. Let dry for 24hrs.\nIf you are assembling using case miter joints, then start by dry fitting all of your joints. If any splines are tight, sand with sand paper on a paint stick until it fits snug, but not tight.\nNext, apply glue to the faces and all sides of the slots on both sides of the joint. Insert the spline and then use masking tape and a clamp to hold the joint together while the glue dries. Repeat these steps until the holder is completely assembled. Now let it dry for 24hrs.\nOnce dry, cut the splines flush with a pull saw, then sand smooth. If there are any gaps, rub wood glue into the gaps and then sand again. The sanding dust will mix with the glue to create the perfect colored filler. Repeat as as needed.\nStep 6: Final Sanding\nSand using 80, 120 and 220 grit sand paper until smooth.\nStep 7: Mounting Holes\nBuy the mounting hardware you want to use and then drill counterbored holes.", "76" ] ]

[ 7286, 8043, 5271, 4773, 8836, 1076, 7225, 4465, 7538, 1099, 3045, 10400, 4477, 6755, 4507, 2833, 8821, 3740, 4825, 10990, 6292, 5095, 3050, 11066, 5724, 6934, 1833, 4670, 4551, 9573, 2380, 10636, 4599, 10995, 5522, 775, 9798, 10102, 1688, 2162, 10166, 5195, 1095, 1288, 5880, 5764, 3834, 2637, 11150, 4198, 9856, 7100, 2865, 11169, 1648, 7700, 8229, 9460, 3503, 8746, 6341, 10060, 2678, 1981, 7573, 6173, 7012, 1796, 10377, 4149 ]

[ [ "Unit cell structure of ionic crystal\nI have a question about the structure of an LiH unit cell, and while this is related to a homework problem, it isn't the problem itself, I'm just looking for conceptual understanding. I've already found that there should be 4 Li+ ions and 4 H- ions in one unit cell. However, I am struggling with how they will be arranged. Because the number of LiH molecules is 4, I am fairly certain that the structure intended for this problem is face-centered cubic lattice. This is where my conflict begins. In my class we have had the face-centered cubic unit cell described as (for one element) an atom at each corner and an atom in each side. From this arrangement we get (1/8)8 + (1/2)6 = 4 atoms.", "793" ], [ "Now, I've seen a description online of the face-centered cubic structure for NaCl as \"We can think of this as chloride ions forming an FCC cell, with sodium ions located in the octahedral holes in the middle of the cell edges and in the center of the cell. The sodium and chloride ions touch each other along the cell edges. The unit cell contains four sodium ions and four chloride ions, giving the 1:1 stoichiometry required by the formula, NaCl\" (Chemistry LibreTexts). For me this makes a certain amount of sense, because this would give 4 cations when you use the same counting principle as before. However, I've seen multiple diagrams online that contradict this, such as: https://images.app.goo.gl/CGAsc4xAJM39tMgi8. This seems to claim that the center image is the unit cell, and while it does have 4 of each ion \"on\" it, it does not seem to fulfill the same structure as the aforementioned unit cell suggestion. Is the problem here just that they are showing 1/8th of the full unit cell for simplicity? If not, I am even more confused.\nThank you for reading this extraordinarily long question for what could be a very simple answer! And please don't roast me too hard, I've never posted here before.", "870" ], [ "What does the concept of \"free electron\" mean in the context of band theory?\nOften when conductivity is explained through band theory, the term \"free\" tends to crop up. As an example, I often come across descriptions of the valence band as a highest filled set of states occupied by electrons bound to their specific atoms; raising them to the conduction band supposedly \"frees\" them so that they can move freely in the metal, thereby enabling them to contribute to a current when an electric field is applied.", "927" ], [ "In fact, in my introductory solid-state physics book, the additional electron contributed by a donor in a doped semiconductor is referred to as \"loosely bound\" to the donor ion, requiring a push into the conduction band to break free and become a charge carrier.\nAt the same time, I was also given to understand that the electrons of a valence band do not contribute to a current when there is an electric field, because their respective velocities balance each other out perfectly; there is no net velocity and hence no net movement. Raising an electron into the conduction band essentially means creating a hole in the valence band so that the electrons can now redistribute (in k-space) and thereby achieve a non-zero net velocity.\nBut according to this latter statement, the electrons in the valence band should contribute to a current across the metal when an electric field is applied.\nA) How then can the valence band electrons be bound to a specific atom, as the former statement claims, if they are simultaneously capable of acting as charge carriers? Also, how then can the donor electron - which occupies an energy state above the valence band - be \"loosely bound\" to the donor atom, when the electrons below aren't?\nB) Assume that we raise the temperature enough (without the metal somehow disintegrating) so that some electrons from even the lowest band leave for higher energy bands. Will the holes that are left behind in this lowest band also mean that the remaining electrons in this band can carry charge, similar to how the electrons in the valence band with holes were able to carry charge?\nI'll be grateful for anything that can help me clear up this mess!", "531" ], [ "Justification for Freezing Point Depression & Boiling Point Elevation in Solutions?\nI was wondering if the following justification for freezing point depression and boiling point elevation are conceptually correct. The reason why I ask this question is because I have been self studying chemistry for a course I will be taking this fall, and I don't have a human reference to check with. My book is also very confusing on this subject, and I don't have a world renowned memory (meaning I'd rather understand than memorize the equation), so I tried to think about it and came with the following conclusions:\n-Freezing Point Depression: When a solvent is not pure and has particles dissolved in it, there are constituents (be it molecules, ions, etc.) that take up volume in the solution. For freezing to occur, these constituents need to aggregate to form a lattice, bonds, etc. Say we have a pure solvent X. This process occurs at a temperature Y.", "793" ], [ "However, when this solvent is not pure and has dissolved solutes, there is \"blockage\" impeding these constituents from aggregating and bonding. Therefore, the temperature Y needs to be reduced further to slow down the kinetic energy of all constituents in solution (solvent and solute), which gives a greater statistical probability of intermolecular forces getting an opportunity to bind solvent-solvent constituents.\n-Boiling Point Elevation: Boiling, if I'm not mistaken, occurs when the partial pressure of a vapor exceeds atmospheric pressure. For a gas to enter the vapor phase, molecules in solution need to have a certain kinetic energy (as specified by a <PERSON> distribution) to free themselves of the intermolecular forces in the solution phase and become a vapor. When a pure solvent is now diluted with other particles, the new solute-solvent bonding energy needs to be overcome to allow a solvent molecule to exist as a vapor. One way to overcome this energy is to increase the average kinetic energy of all molecules, and this is done through a temperature increase.\nThis is for an introductory chemistry course, and I'm not sure if my explanations are sound. I just want a yay or a nay in terms of my logic, because I don't have the most intimate background in chemistry and I'm trying to conceptually understand things.", "273" ], [ "Is this stoichiometric question answerable? (unknown variable)\nThis question kind of borders on the fields of both semantics and math, as well as chemistry, but I still believe this is the right place to ask.\nOn a test I took, a question was posed as such:\nVia titration we are adding a solution of 25 ml, with 0.5 M NaOH, to 25 ml of HCl. What will the concentration of the acid be?\nNow, this question seemed a bit strange to be, and it was definitely new. I'm used to calculating concentrations after dilution and other stoichiometric calculations, but this question seemed like a misworded version of those other questions I've grown familiar to.\nSo, I asked my teacher if she could clarify. First I asked whether the 25 ml of HCl was pure HCl, or a water solution with HCl in it. She said it was pure HCl. Then I asked if she was looking for the concentration of the acid before ANY reaction between the NaOH and the HCl had occured. To this, she also said yes.\nThe options were:\n0.25 M\n0.5 M\n0.75 M\n1 M\nI answered 1 M, my reasoning being that 25 ml of HCl is the same volume as 25 ml of water with NaOH. Obviously, this reasoning is quite flawed, but I didn't have anything better. The answer was wrong.", "870" ], [ "However, when my teacher told me what was meant by the question afterwards, her explanation did not align with the question, nor her previous clarifications. She said that this was a simple case of:\n$$C_1 \\times V_1 = C_2 \\times V_2$$\nWhere $C_2$ was the unknown, since the concentration of HCl was not specified. I don't see how this makes sense. All the question is saying, is that there is a 25 ml container, with HCl in it. It doesn't even say that this 25 ml consists of a water solution with HCl in it, but a more knowledgeable chemist would've known that HCl cannot exist outside of a water solution (that's what my teacher said at least).\nThen the the question says that 25 ml of water, with a concentration of 0.5 M of NaOH is added. And from those two values, I'm supposed to find the concentration of HCl. That basically means:\n$0.025$ l of H$_2$O$ \\times 0.5$ M NaOH(aq) $= 0.025$ l of water $\\times x$ M HCl (aq)\nWhich would then make the answer 0.5 M. Maybe she wanted me two add the two volumes, which would make sense:\n$0.025$ l of H$_2$O$ \\times 0.5$ M NaOH(aq) $= 0.05$ l of water $\\times x$ M HCl (aq)\nWhich would then make the answer 0.025, which wasn't even an option.\nBut even if it was, it still wouldn't make sense to me. Just because you have a solution with a given volume and an unknown concentration, adding another solution with a known volume AND concentration won't just magically let you know what the unknown concentration in the original solution is, now in this new solution. Or am I wrong?", "870" ], [ "Should I relate the number of moles between substances when converting weight units?\nGood day! I graduated from an undergrad degree of chemistry almost 3 years ago but I'm frustrated that I fail to reconcile these things:\nIn gravimetric analysis, to get the correct amount for the desired way of expressing the analysis result, we convert the mass of the acquired substance to the desired form, and in doing this, we should relate the number of moles of the acquired substance to the desired substance. For example, if you desire to get the grams $Al$ from a sample which you assayed gravimetrically until you have formed $Al_2O_3$, then you have to use the following formula:\n$\\text{grams } Al = \\text{grams } Al_2O_3 \\times \\frac{2\\times MW Al}{MW Al_2O_3}$\nwherein the factor $2$ in the numerator was obtained from the term $\\left( \\frac{4 \\text{ mol } Al}{2 \\text{ mol } Al_2O_3} \\right)$, which arose from the oxidation reaction $4Al + 3O_2 \\rightarrow 2Al_2O_3 $.\nNow, the question is, should I also use this method of conversion if I just want to express %Al from a %$Al_2O_3$ concentration of a certain substance, even if I don't plan to do a gravimetric analysis to find it? Also, this method of conversion is reaction-specific, but there could be many different ways, not only single-step chemical equations but also multiple-step ones in which the overall mole relation of the substances in a given chemical equation is different from that of a different chemical equation.\nAlso, what about the expression of ppm $N$ from ppm $NO_3$ and ppm $NO_2$? Does their conversion method work in the same way in which you have to know the reaction involving $N$, $NO_3$ and $NO_2$ to know their mole relations, knowing that monatomic $N$ is not very easy to generate? In this case, I can only see that the conversion method is based on the number of atoms the primary element in each form not on a certain reaction like thee previous case.", "565" ], [ "But if that's the case, then I have another contradicting case to show:\nAnother one is that of between $NaOCl$ and $Cl_2$ in disinfection solution formulations. If you base it on the last method I mentioned, then the mole ratio should be 2 mol $NaOCl$:1 mol $Cl_2$ because you only have one $Cl$ atom in $NaOCl$ while $Cl_2$ has 2, but according to all of the reputable resources I have found in the internet, the mole ratio here is 1:1. The reason here is supposed to be because of the chemical equation $Cl_2 + 2NaOH \\rightarrow NaOCl + NaCl + H_2O$.\nIf the answer is supposed to be obvious after all these, or I am just completely missing the point, I hope you would be kind to point it out clearly because it's really bogging me down.", "870" ], [ "Balancing by oxidation numbers method multiple atoms\nIn my Chemistry textbook, the rules for balancing a chemical equation using the Oxidation-Number method are as follows:\n1. Assign oxidation numbers to all atoms in the equation.\n2. Identify the atoms that are oxidized and the atoms that are reduced.\n3. Determine the change in oxidation number for the atoms that are oxidized and for the atoms that are reduced.\n4. Make the change in oxidation numbers equal in magnitude by adjusting coefficients in the equation.\n5. If necessary, use the conventional method to balance the remainder of the equation.\nI understand how to do this for simple equations, such as $$SnCl_4+Fe\\rightarrow SnCl_2+FeCl_3$$ Following the steps:\n1. $Sn^{4+}+4Cl^-+Fe^0\\rightarrow Sn^{2+}+2Cl^-+Fe^{3+}+3Cl^-$\n2.", "979" ], [ "oxidation: $Fe^0\\rightarrow Fe^{3+}$ (Fe); reduction: $Sn^{4+}\\rightarrow Sn^{+2}$ (Sn)\n3. oxidation: +3; reduction -2\n4. $3SnCl_4+2Fe\\rightarrow 3SnCl_2+2FeCl_3$\n5. (no change necessary, already balanced)\nThe Problem: Notice how Sn and Fe (the reduced and oxidized atoms) all have subscripts of 1. However, when their subscripts differ, I'm not sure how to balance it.\nFor example, I can easily balance the following equations by inspection, but not so easily by this method of oxidation numbers:\n$$KClO_3\\rightarrow KCl+O_2$$ (O is oxidized, subscripts of 3 and 2)\n$$NH_3+NO_2\\rightarrow N_2+H_2O$$ (N is oxidized and reduced, oxidation numbers of -3, +2, and 0)\nAnd this gets even more complicated when the subscripts differ and there are more than two elements whose oxidation numbers changed (are reduced or oxidized), e.g.,\n$$NH_4ClO_4+Al\\rightarrow Al_2O_3+HCl+N_2+H_2O$$ (Al and N are oxidized, Cl is reduced)\nFor all of these, I get stuck on the fourth step. Determining oxidation numbers and calculating the change is not the problem, but figuring out how to do it with larger or different coefficients as in the examples above is the problem.\nThe five general steps in my textbook don't help me understand this method much with more complicated methods such as this. Could you give me a more thorough explanation— a better explanation or a general rule— of how to solve all of these? Thanks.\nFYI: I am not asking you to do my homework, but this is a homework question this meta answer. I have already done the questions via inspection but want to learn how to use this alternative method.", "979" ], [ "React these iron oxide, ammonium nitrate, and sucrose\nTwo questions: what reaction forms between ammonium nitrate, black iron oxide, and sucrose; and a story related question.\nSo here's the whole story:\nSo I was playing around a few months ago and stumbled upon a mixture that generated something similar to Black Snakes (firework). I recently decided to demo this mixture to someone, but I could not find my notes about the experiment, so I decided to try to replicate the mixture from what I remembered.\nI am certain that the mixture contained ammonium nitrate, black iron oxide, and some sort of fuel (probably sucrose, impure in the form of powdered sugar). Combining these three ingredients (one part by volume, whatever particle sizes I have), and igniting with a lighter, the mixture does form black snaking ash, and turns red and crumbles as it cools.\nQ1: So, what kind of reaction has taken place between the black iron oxide, ammonium nitrate, and sucrose?\nIf I leave out any one of the ingredients, the ash snake does not form, so all three compounds are definitely involved. If we leave out either the ammonium nitrate or sucrose, little happens with the application of heat.\nHere's a picture after the fact.\nI haven't had a very good batch since I lost my notes, so maybe I am missing an ingredient, or maybe I just haven't got the right ratios.", "938" ], [ "Q2: Any Suggestions?^\nEdit: I have been having more success with this mixture (by volume): 1 part ammonium nitrate 1 part potassium nitrate 2 parts black iron oxide 2 parts sucrose\nMix contents and melt over medium indirect heat (skillet is fine); once it is all melted, immediately remove from heat and form into pellet as it cools. The mixture will reduce in volume by several times. I suggest doing this in small batches since it can self ignite if you are not careful, or do not heat it at the right rate.\nIf the ammonium nitrate is omitted or substituted by potassium nitrate, the ash does not expand or cohere. So the ammonium nitrate is doing something more than just providing oxygen here. The reduction of iron oxide seems to make the ash less monolithic, and moderate reductions in iron oxide forms snakes that fall apart quickly during production.", "842" ], [ "Using a Chi-Square distribution table to calculate fraction of gas molecules with activation energy\nI couldn't decide whether to ask this to Chemistry, Physics or Statistics stack exchange. Hopefully I made the right choice.\nAccording to this Wikipedia page, while the speed of particles in an ideal gas follows a Maxwell-Boltzmann distribution, the energy distribution in a collection of ideal gas molecules follows a Chi-Square distribution with however many degrees of freedom as the molecule. i.e. 3 for monatomic, 5 for diatomic (at moderate temperatures).\nAs an example computation to try this out, I wanted to find the activation energy of a reaction which would have 10% of the monatomic gas molecules eligible for reaction at temperature $ 300 \\text{ K} $.\nFrom the Chi-Square distribution, we should have $ \\frac{E}{RT} \\sim \\chi^2_3 $.", "565" ], [ "From the inverse Chi-Square table, at a significance level (i.e. right-tail proportion of the distribution) of 0.1, the critical value is 6.251, which implies that we need $ \\frac{E_a}{RT} = 6.251 $ so the activation energy should be no more than $ E_a = 8.314 \\times 300 \\times 6.251 = 15.5912 \\text{ kJ mol}^{-1} $.\nThis seems like a reasonable number but then I tried checking the answer by working it out directly from the distribution of energies (also given on the Wikipedia page). I worked out that\n$$ P(E > E_a) = \\frac{2}{\\sqrt{\\pi } (R T)^{3/2}} \\int_{E_a}^{\\infty } \\sqrt{E} \\exp \\left ( -\\frac{E}{R T} \\right ) \\ \\text{d}E $$\nEvaluating this numerically for $ E_a = 15591.2 $ and $ T = 300 $ gave $ P(E > E_a) = 0.005847 $, or about 0.5% of the particles, which is very different to the 10% I specified when solving it the first way, showing that something went wrong when I was working it out.\nA third method is to use the commonly-cited (but it seems nowhere derived) result from the <PERSON> equation that $ \\exp(\\frac{-E_a}{RT}) $ is the fraction of particles with $ E > E_a $. Using this gives a proportion of 0.00193 = 0.2%, which differs yet again from both previous answers. I am very skeptical of this result though because neither that integral nor the Chi-Square inverse pdf have a nice closed form, and this is a suspiciously clean simple formula to say it's supposed to do the same thing.\nDoes anyone know the correct way to go about finding particle energy proportions? It would be nice to be able use Chi-Square correctly here as I find it interesting how different areas of science and statistics fit together.", "565" ] ]

[ 3230, 11172, 11257, 933, 7294, 10230, 5943, 4472, 11130, 5831, 8217, 6194, 4135, 1213, 8533, 5786, 4358, 2092, 4823, 10198, 7110, 2062, 10901, 6642, 6034, 4722, 10252, 3687, 7658, 2125, 8845, 9926, 7304, 10074, 3597, 2464, 7045, 8827, 46, 3328, 1065, 874, 1684, 5349, 4389, 4151, 9715, 1952, 10091, 9738, 11168, 10469, 3333, 809, 2748, 4459, 5282, 11186, 5390, 1444, 4046, 3927, 6015, 10490, 7693, 9469, 2743, 7352, 8816, 2305 ]

[ [ "New Appointments to the Polish Constitutional Tribunal May Be Unconstitutional · Global Voices\nA Polish National Assembly sitting on June 4th 2014. Photo by <PERSON>, CC BY-SA 3.0.\nSeveral dozen people spontaneously gathered on Wednesday, November 25 in front of the Polish Parliament building, ignoring the late hour and below-zero temperature, to protest the latest resolution passed by Parliament during a special night sitting.\nIt wasn't the first time since the recent elections that an important decision was brought in a rush, during the night, making it impossible for either the public or the opposition to discuss the bill before it was put to the vote.\nTwitter user <PERSON> wrote:\nJak tak dalej pójdzie, to trzeba będzie w porządku <PERSON> zmienić “porządek dzienny” na “porządki nocne”\n— <PERSON> (@PiotrWitwicki) November 25, 2015\nIf all this is to go on, we should change Parliament's agenda from a daily agenda to a nightly one\nThe highly controversial resolution passed by the newly elected ruling party, Law and Justice, cancels the appointment of five judges to the Constitutional Tribunal, who had been appointed by the previous parliament. Many authorities on the country's constitution have gone as far as claiming that the new resolution is unconstitutional and, hence, illegal. This decision not only seems to ignore provisions of Poland's Constitution, but also breaks one of the oldest rules of any legal state — that laws cannot and should not be retroactively applied.", "1017" ], [ "What makes things even more complicated is the fact that such a decision could only be made null and void by the Constitutional Tribunal itself, if it were to discover the incompatibility between the act of choice itself, and the law on which it was based.\n<PERSON> attached a video from the demonstration, saying:\n<PERSON>… <PERSON>… https://t.co/3mbEmYYFx4\n— <PERSON> (@DMarcin93) November 26, 2015\nAnd so it begins…Quite fast…\n<PERSON> wrote:\nPod Sejmem demonstracja ok. 40 osób….szybko ludzie mają dość.\n— <PERSON> (@ArturGorczynski) November 25, 2015\nAround 40 people gathered in front of the Parliament, people are getting fed up quite fast.\n<PERSON> added:\nIdę spać, trzymając kciuki za tych, co się zbierają pod sejmem.\n— <PERSON> (<PERSON> November 26, 2015\nI go to sleep keeping my fingers crossed for those in front of the Parliament.\nAlthough the decision is mostly seen as unconstitutional, it has its supporters.\n<PERSON> wrote:\n<PERSON> pisze że pod Sejmem gromadzą się tłumy.. Są obecni <PERSON>,<PERSON> i rodziny tych którzy stracili posadki #ASZdziennik\n— <PERSON> (@Sylwia2404) November 26, 2015\n<PERSON> [another Twitter user] writes that crowds are gathering in front of the Parliament. The only ones present were <PERSON>, <PERSON> and families of those who have just lost their cushy jobs\nMany people seem to think the protest is temporary, doubting the ability of citizens to get politically involved.\n<PERSON> asked:\nDzisiejsze wydarzenia na trawniku pod sejmem i w sejmie (nie wiem ocb) będą miały jakiś wpływ na życie szaraka czy to zwykłe pierdolamento?\n— <PERSON> (@maciek90legia) November 26, 2015\nSo as for tonight's events both on the lawn in front of the Parliament and in the Parliament itself (I have no clue what's going on) are they going to influence an average guy or is it just bullshit?\n<PERSON> wrote:\nJuż kiedyś PO zwołało protest, ba, całe miasteczko pod sejmem. Trwało dzielnie do pierwszej kropli deszczu.", "1017" ], [ "Poles Rally to Defend the Independent Judiciary From Ruling Party’s Reforms · Global Voices\nResidents of Warsaw gathered in front of the Presidential Palace. Photo by <PERSON>, CC-BY.\n2017 marks a century since the establishment of the Polish Supreme Court, but instead of celebrating, Poles are taking to the streets in defense of the country's independent judiciary.\nThe ruling Law and Justice (PiS) party, which has held power for a year and a half, has in rapid succession taken over the public prosecution authority, the Constitutional Tribunal and — on July 12, 2017 — the National Council of Judiciary, which appoints and promotes judges.\nAnd now the ruling party has its eyes on the Supreme Court. A set of legislative changes, introduced last week and voted to a parliamentary committee on July 18, provides for an on-the-spot purge of the entire cadre of Poland’s highest appellate panel, which consists of 83 top judges. The dismissals would take place one day after the law’s promulgation. The only exceptions are to be made by the minister of justice, also a member of Law and Justice. The aforementioned National Council of Judiciary, under the influence of the party, will then fill the empty seats.\nThe revamped Supreme Court would have final appeal powers over all civil and criminal cases.", "1017" ], [ "The bill also provides for the establishment of the new Disciplinary Chamber within the Supreme Court, which will make final determinations on disciplinary actions against all judges in the country.\nIn a surprise move on July 18, as the bill was being debated, President <PERSON>, a former member of Law and Justice party, announced he will not sign the bill regulating the Supreme Court until his new amendments to the National Council of Judiciary bill passed the week before were incorporated. These amendments provide that the members of the council are to be elected by a three-fifths parliamentary majority, instead of the ordinary majority suggested by the original bill, making it much harder for Law and Justice representatives to elect their candidates. However, many consider the new law to be unconstitutional and argue that the president's proposal, if adopted, wouldn't change that fact.\nIn response, the residents of Warsaw and other major Polish cities took to the streets urging the president to veto the bill entirely. The gatherings were a continuation of demonstrations that began over the weekend and grew more massive on the day the parliament was debating the controversial bill.\nThousands of people with candles in front of the Supreme Court of #poland #Warsaw #KOD #ZamachLipcowy #ObrońmyDemokracje #ŁańcuchŚwiatła pic.twitter.com/Daqhmwcj48\n— <PERSON> (@kstawinska) July 16, 2017\nThe protests were organized by Polish Judges Association “Iustitia” and Akcja Demokracja (Action Democracy) in 33 cities across Poland.\nThe video below, taken by the author on July 18, shows participants in Warsaw singing the Polish national anthem:\nhttps://globalvoices.org/wp-content/uploads/2017/07/20170718_214718-online-video-cutter.com_.mp4\nAnd in this footage, residents of Warsaw shout, “We want the veto! Free judiciary!”\nhttps://globalvoices.org/wp-content/uploads/2017/07/20170718_211124.mp4\nThe hashtags initiated by Akcja Demokracja include #ŁańcuchŚwiatła (meaning “chain of light”), #wolnesądy (meaning “free judiciary”) and #chcemyweta (“we want veto”).\nWarsaw rally for #democracy and #ruleoflaw in #Poland continues… Candles symbolise hope for freedom and a better future. pic.twitter.com/QizU5OCZdp\n— <PERSON> <PERSON> 18, 2017\nA heated discussion in the Parliament lasted almost until midnight, with the opposing minority trying to stop the Supreme Court bill from being passed. The final vote is expected to take place on July 19.", "1017" ], [ "Poland: Football Fans Clash Ahead of Poland-Russia Game · Global Voices\nOver 180 people were detained due to clashes that broke out between rival Russian and Polish football fans in Warsaw on June 12. Unrest started during the march organised to mark the Russian National Day, attended by thousands of visiting Russian fans ahead of the Poland-Russia Euro 2012 game at the National Stadium.\nConcern about possible tensions had been expressed by several newspapers and public figures prior to the march, given the troubled history of the two countries. <PERSON>, the Mayor of Warsaw, recognised the problem, but stated that “the Russian fans’ delegation promised that there wouldn't be any political exclamations on their part.”\n<PERSON> called the day of the march “the main challenge for the city during the Euro 2012 championship.”\nClashes in the centre of Warsaw. Photo by <PERSON>, used with permission.\nThe idea of holding the march had also caused quite some buzz among the Polish netizens. A few days before the march, Salon24 user <PERSON> wrote [pl]:\nClashes during the Euro are inevitable.", "910" ], [ "[…] Polish hooligans will definitely oppose the march, and organise some spectacular fights to “repay the Russians” for the years of communism, partitions and the bloody supressions of the Polish uprisings in the 19th century. This kind of behaviour is almost openly encouraged by the right-wing journalists.\nSalon24 user <PERSON> also pointed out [pl] the stance that the mainstream media took in this situation:\nThe mainstream media suddenly started to act as if they were completely crazy. Maybe the journalists got so sucked into the atmosphere of the Euro that they forgot their usual strategy of promoting the Polish-Russian reconciliation?\n<PERSON> wrote [pl]:\nIf the Mayor allowed a march of two rival Polish football teams through the city center, would anyone be surprised by the clashes?\n<PERSON> called for the reasonable evaluation of the unrest [pl]:\nThe German media describe the clashes objectively, as a minor outburst of aggression on the both sides\nClashes in the centre of Warsaw. Photo by <PERSON>, used with permission.\nSome people are interpreting the riots as part of the political game between the ruling party and the opposition.\n@DziadekWaldemar wrote [pl]:\nThere is only one political party in Poland that can gain from those clashes, and it's the right-wing [PIS] and its supporters, they have links with the hooligans […]\nSalon24 user <PERSON> wrote [pl]:\nThe ruling party is ready to burn down half of Warsaw only to stay in power. These clashes are the only thing that can draw attention of the public away from almost 3 million Poles living in poverty.\nSome people point out that the hooligan clashes in Warsaw gained much more attention in the interational press than the “March of the Millions” – a massive protest rally organised on the same day in Moscow by the opposition.\n<PERSON> wrote:\nWELL DONE <PERSON>! A march of 200,000 opposing him, held in Moscow, was outdone by some minor clashes in Warsaw. […]", "1017" ], [ "President <PERSON>’s Controversial Pardon Has Not Put Poles in a Forgiving Mood · Global Voices\nPolish lawyer and politician <PERSON> assumed the office of President in August 2015. Photo by <PERSON>, September 12, 2013. CC 2.0.\nEarlier this month, just a day after the new Polish government was sworn in, President <PERSON> made the controversial decision to pardon <PERSON>, a member of <PERSON>'s former party, Law and Justice.\n<PERSON> was convicted of abusing his powers as head of Poland's Central Anticorruption Bureau, where he served until 2009, during which time the Law and Justice party controlled the Polish government. Before his pardon, <PERSON>'s sentence had not yet entered force, as he was awaiting an appeal trial.\nAlthough the conviction itself was seen as controversial and some considered it a political move made by the previous government (controlled by rivals in Civic Platform), many say <PERSON>'s decision to pardon <PERSON> is surprising and possibly inappropriate. Had <PERSON> lost his appeal, he would have been barred from holding public office ever again, and he may have been sent to prison for many years. <PERSON> currently serves as the head of special services in Poland's new government.\nPolish social media users soon voiced their opinions on Twitter. <PERSON> wrote:\nPrzypominam, że ułaskawienie potwierdza wyrok.", "1017" ], [ "Od dziś o zainteresowanym można pisać per “przestępca”\n— <PERSON> (@konradniklewicz) November 17, 2015\nI want to remind you all that the pardon confirms the ruling. From now on we can call the person in question “guilty”\n<PERSON> also commented on Twitter:\nPAD to chyba zrobił Kamińskiemu krzywdę, bo ułaskawienie nie jest uniewinnieniem. Nie wiąże się z zatarciem. Nie znam się ale to głupie\n— <PERSON> (@FilipLachert) November 17, 2015\nI think that PAD [President <PERSON>] did a disservice to <PERSON>, because the amnesty doesn't mean “not guilty.” It doesn't equal an erasure of conviction. I'm not an expert but I think it was stupid.\nAnother Twitter user, <PERSON>, compared pardons issued by Poland's current and past presidents. As depicted in the picture attached to the tweet, <PERSON>'s pardon was suspiciously just a single sentence long.\nTak na obrazkach wygląda ułaskawienie normalne i ułaskawienie nienormalne: pic.twitter.com/EGi7CXfGBF\n— <PERSON> (@aronsem) November 20, 2015\nOn the attached pictures it can be seen how a normal act of pardon looks like, and how a not normal one looks\n<PERSON> also wrote about the pardon:\nPo to głosowałam na PiS i prezydenta <PERSON> by w moim imieniu ZAWŁASZCZYLI wreszcie państwo , wyrywając je z rąk złodziei i zdrajców\n— <PERSON> (@ISzafranska) November 19, 2015\nThis is why I voted for PiS [Law and Justice] and the Presient <PERSON>, so that they could reclaim the nation and pull it out of the hands of thieves and traitors\nSeveral members of the public complained that <PERSON> has compromised the presidency's impartiality and duty to represent the interests of the nation by indulging in partisan politics. While it's not illegal for the president to pardon a former colleague, <PERSON>'s decision has invited criticisms that he's violated the spirit of his obligations as Poland's leader.\nAlready divided after the elections, Polish citizens continued to be disagree about <PERSON>'s actions.\nPopular blogger and Twitter user <PERSON> posted:\nCoś czuję, że jak będzie za duży jazgot wokół tego ułaskawienia to wkrótce wypłynie jakieś nieznane do tej pory ułaskawienie poprzednika.", "1017" ], [ "Russia’s Democratic Coalition Is On The Ropes · Global Voices\nRussia's opposition Democratic Coalition has been dealt blow after blow in the run up to regional elections. Images mixed by <PERSON>.\nWhen a group of opposition parties joined forces this April, they knew their goal of introducing true political pluralism to modern Russia was a tall order. Nevertheless, the Democratic Coalition forged ahead with plans to back candidates in regional elections this fall, with an eye on the national parliamentary elections in 2016. In recent weeks, however, the Coalition's grand ambitions have collided full force with the harsh reality of politics in <PERSON>'s Russia.\nOn September 13, a number of regional and district elections will be held across Russia. In preparation, the Democratic Coalition organized primaries earlier this summer to chose local candidates, and opposition leaders from Moscow such as <PERSON> toured key regional cities to drum up support. As the election date draws near, however, many Coalition candidates have found themselves unable to make it onto the September ballot.\nIn Russia, signatures from a certain number of supporters must be collected in order for candidates to take part in regional parliamentary elections, and the signatures must be verified by the local Election Commission. The verification process involves cross-checking the signee's identity and address with the database of the regional branch of the Federal Migration Service, and any discrepancies result in disqualification. Signature collection has been the focus of the Democratic Coalition in recent weeks, but this hurdle has so far proven insurmountable for the new opposition alliance. Many of the signatures declared invalid by local officials have been scrapped for dubious reasons, the Coalition claims.\nNovosibirsk\nIn Novosibirsk, Russia's third-largest city, the Coalition submitted about 11,700 signatures. <PERSON> wrote online that those selected were the most perfect from a total of 17,500 signatures the Coalition had collected, and “were double checked by a graphologist, entered in databases for compliance with passport data, and a call center had telephoned almost all the signees.” On July 24, however, the regional Election Commission working group ruled that only 10,187 of the signatures were valid, leaving a total falling 470 signatures short of the required number of 10,657. <PERSON>, the Democratic Coalition’s campaign manager in Novosibirsk, detailed the working group's findings in a post to his website:\nНаписал подробно о том, что означает решение рабочей группы избиркома, и что мы будем делать http://t.co/TfWWwN7Wsm pic.twitter.com/f61cct8Ztb\n— <PERSON> (@leonidvolkov) July 25, 2015\nI have posted details about what the Election Commission working group's decision means and what we will do next\nAfter receiving the Election Commission's ruling, <PERSON>'s campaign team in Novosibirsk undertook a 30-hour marathon session to review all the signatures that had been deemed invalid. They found that in many cases Election Commission employees had introduced typographical errors themselves when entering the signee's information into a computer so that it could be cross-checked with the Federal Migration Service database.", "384" ], [ "They also asserted that the Federal Migration Service database contained outdated information, thus explaining the discrepancies that resulted in disqualification in many cases. The graphic below details the Coalition's findings:\n“The Election Commission working group declared 1487 signatures to be invalid. The results after correcting their mistakes: 615 invalid signatures. 1065 valid signatures.” Graphic labels (top to bottom): “Mistakes in checking. Typographical entry errors. Out-of-date FMS data. Mistakes by FMS. Invalid signatures. Under question. Lack of information. Duplicates.”\n<PERSON>'s team then met with representatives of the Novosibirsk Election Commission on July 27 to present these findings. An official from the regional branch of the Federal Migration Service in attendance dismissed their claims, however, informing everyone that the FMS database was up-to-date and contained no mistakes, wrote <PERSON> on his blog. After being rebuffed, the Democratic Coalition representatives refused to leave the Election Commission building, and were briefly detained by police before being fined for disobeying police orders.", "384" ], [ "Poland: Change to Drug Law, Change in Policy? · Global Voices\nOn December 9, 2011, an important change [pl] was introduced to the Polish drug policy: an amendment to the law on illegal drug possession came into force, which would allow prosecutors to abandon initiation of the criminal procedure against those in possesion of drugs. It is to be possible under three conditions: when defendant is in possesion of only a small amount of drugs, when the drug is for personal use only, and when punishing a person in question would be pointless, due to harmless nature of the crime.\nThe Polish drug law is considered to be one of the most severe in Europe. Possesion of drugs still remains illegal, but from now on it is for a prosecutor in a specific case to decide, whether it is to be treated as an offence or as a misdemeanour. One of the parts of the new amendment, which is surely to be questioned, is the lack of a definition of what “a small amount of drugs” is.\nEven though the change in law is small and its influence depends entirely on the prosecutor's interpretation of it, it is a step in the direction recommended by many influential politicians and experts around the world.\nIn June 2011, a report by the Global Commission on Drug Policy called for the legalisation of some drugs and an end to the criminalisation of drug users. According to the report, anti-drug policy has failed to achieve its main goal – putting an end to or limiting organised crime. It has costed taxpayers millions of dollars and caused many people to die. In the report, the UN estimates are cited, which state that drug consumption increases every year.\nThe new law, passed by the parliment in March 2011, caused a heated debate, with 258 deputees in favour of the act and 159 opposing it. The blogosphere was also very fragmented in its evaluation of the parliment's decision.\n<PERSON> writes [pl]:\nWe shouldn't create a myth, claiming that all drugs are similarly dangerous. Decriminalising possesion of marijuana, or even legalising it, won't cause the Polish society to collapse.", "289" ], [ "It won't cause widespread drug addiction. Possibly, more people would dare to use it, but would do so occasionally. I am against legalisation of drugs other than marijuana, though I strongly believe that drug-users should be offered health and treatment services insted of being sent to jail.\nBlogger <PERSON> doesn't approve of the new act, and being a supporter of the opposition party, blames the ruling one for passing it [pl]:\nIt all began in the [Sejm], in no time [the Senate ] will join in, and then the President would be given a chance as well [to overrule the act]. Less than a year after [the tragedy in Smolensk], thanks to the elimination of the threat of a veto from the late president [<PERSON>], supporters of the drugs legalisation achieved their first big victory. Which MPs voted for the act, supporting the legalisation of the so-called “light drugs”? […] 100 percent of the opposition voted against it!\nOn the bangladeszcz blog, where news on the Polish drug policy are published, the editor writes [pl]:\nA step towards normalcy! Sejm moderates the drug law!\nThe most heated debates took place among those who commented on the official online news.\n<PERSON> from Boston, USA, writes:\nOnce again the [Civic Platform-Polish People's Party] coalition shows that it only undertakes legislative actions to harm Poland and the Poles. Don't you see, those back in the country, what these people are doing?!?! These are not innocent children!!! These are people who consequently destroy the Polish sovereignty with unbelievable speed!\n<PERSON> replies [pl]:\nThis is the best change in the legislation that the ruling party has ever introduced. Unfortunately, we have to admit that those changes are really small. Depenalisation of drug users (as opposed to drug dealers) should be obligatory. A huge mistake was made by turning down the amendment proposed by MP <PERSON>, which suggested establishing actual limits for the amount of a drug considered as “for personal use.”\nLGPhantom adds [pl]:\nThis amendment doesn't change the situation at all, it doesn't change the Polish drug policy.\nMany Twitter users, like @Liroy or @bartoszc, recommended [pl] a YouTube video, where a Harvard economy professor explains why some of the drugs should be decriminalised:\n<PERSON> wrote:\n[Law and Justice] says that drugs should be illegal, but what is more addictive – marijuana or Law and Justice membership?", "289" ], [ "Russian opposition leader <PERSON> calls for continued resistance after receiving 9-year sentence · Global Voices\nScreen Shot from BBC's YouTube channel showing <PERSON>'s trial inside a prison.\nWhile global public attention is mostly focused on Russia's invasion of Ukraine, other events taking place in Russia go almost unnoticed, including the Moscow trial of <PERSON>, the country's most prominent opposition leader.\n<PERSON> returned to Russia on January 17, 2021 from his stay in a German hospital recovering from an attempt to poison him. On that day, he was arrested right inside Moscow airport on charges of violating the terms of his probation in a previous embezzlement case, and taken into custody.\nAfter a hasty court hearing, he was sentenced to 3 years in prison and sent to a prison in the Vladimir region, not far from Moscow. Given his popularity in Russia after he unearthed massive corruption and targeted President <PERSON> , it became obvious that the story would not end with this verdict, and that the Russian authorities would try to find another reason to keep him imprisoned longer.\nA year after his arrest, on January 25, 2022, the Federal Financial Monitoring Service of the Russian Federation (Rosfinmonitoring) included <PERSON> on the list of extremists and terrorists. Right after this, a new case was submitted to the Lefortovo Court of Moscow against <PERSON>. This time, he was accused of contempt of court and fraud . He was charged with the latter because he allegedly insulted a judge who had sentenced him in a previous trial in 2021.\nTo understand how far-fetched this accusation is, it is worth looking closer at the list of alleged insults : “Your Honor, you are breaking the law,” “My God.” The harshest words uttered by <PERSON> during the meeting were “disgusting”(омерзительный), “vile”(гнусный), and “go nuts” (офигеть), and they weren't even addressed to the judge.\nAs for the second part of the accusation regarding fraud, it relates, according to the prosecution, to the collection of money for <PERSON>'s flagship project Anti-Corruption Fund (FBK, a non-profit organization that investigates, discloses and prevents corruption in the highest authorities) that was allegedly spent for “personal needs and for extremist purposes.”\nThe reality is that about 300,000 people voluntarily donated their funds to the investigations of the FBK organization, of whom only four felt deceived and filed a lawsuit . An investigation by members of FBK reported that two of those were fake victims, and the other two were entrepreneurs investigated in unrelated criminal cases, and might have been pressured by security forces to act as they did to help with their own cases, as is often the practice in Russia.\nSpecial measures for a special trial\n<PERSON>'s trial was conducted in unusual circumstances: Instead of bringing the defendant to court for hearings, the court itself moved several times to the prison located in a small town in the Vladimir region. According to <PERSON>'s lawyer , this is an unusual decision and a rather rare case in judicial practice. Nevertheless, the authorities did not announce why they decided to hold the hearing in a prison instead of transporting <PERSON> to Moscow.", "880" ], [ "Journalists were allowed to watch the trial from a separate room through a TV screen, yet the transmission was frequently interrupted for alleged technical reasons. Though the hearing was formally declared open to anyone, that fact that that it took place inside a prison made it decidedly not. Everything was done to keep the trial as underreported as possible and kept away from the public eye.\nOne possible explanation for such measures is that, as expected, <PERSON> used the opportunity of the trial to express his views on Russia's invasion of Ukraine. An Instagram video of one of the hearings shows him saying: “ I am against this war. I consider it immoral, fratricidal and criminal. It was started by the Kremlin gang to make it easier for them to steal. They kill for the sake of stealing. … I am against this war.”\nThrough his social media accounts, <PERSON> also called on Russian citizens to protest to express their disagreement with the actions of the Russian authorities. He concluded by saying: “ If prison time is the price for my human right to say what I consider necessary and the civil right to fight for a better future for Russia, then they can ask for 113 [years]. I will not give up my words and what I did.", "600" ], [ "Former Ukrainian PM <PERSON> Officially Supports #Euromaidan Movement · Global Voices\nAccording to her official website, former Ukrainian Prime Minister <PERSON> has officially joined the Maidan Civil Movement, a newly formed civilian organization stemming from the Euromaidan movement, just as the protest that began in Ukraine in November 2013 enters its second month.\n<PERSON>, jailed in 2011 for allegedly “exceeding authority”, is considered by many around the world to be a political prisoner, while Ukrainians are divided on their opinions of her. Most Ukrainian citizens condemned her imprisonment in 2011, some claiming that the current regime's only reason for doing so was to remove her from politics after current Ukrainian President <PERSON> won the 2010 presidential election, with <PERSON> as his opponent in the run-off round, by just 3.5 percent.\nIn a YouTube video posted by Ukrainian Channel 5 and released on <PERSON>'s official site, the founders announce the new Maidan Civil Movement's inception before thousands of protesters gathered in Kyiv's Independence Square:\n<PERSON>'s photograph has been gracing many posters and billboards related to the Euromaidan protests in recent weeks, and the jailed former prime minister's daughter has recently, along with other supporters, demanded the immediate release of her mother amid the growing anti-government demonstrations in the country. Other protesters are requesting that <PERSON>'s image be removed from any Euromaidan-related visual materials, not explicitly against <PERSON>'s person and image, but rather as a continuous request by the civilian movement to keep the protests unrelated to any political party or figure.\nA recent post titled “<PERSON> Isn't Who You Think She Is”, Policymic.com explains <PERSON>'s role in the country and the on-going protests:\nOngoing protests are not about <PERSON>. Although, how she was treated has further undermined people's trust in the president and his regime, and this is reflected in their calls to keep politics (existing slogans of political opposition) out of Maidan.", "534" ], [ "As an example, a petition was recently started on Avaaz to remove her portraits from the infamous Christmas tree. Currently, people see existing political opposition, including <PERSON>'s “Fatherland” party, as part of the political problem rather than its solution. However, as of yet, the civil society is unable to offer new leaders of their own. A workable solution will have to come from their collaboration, but an effective recipe has yet to be found.", "339" ] ]

[ 1929, 549, 2835, 7273, 11428, 3600, 2961, 272, 7890, 5134, 8232, 6246, 10101, 2517, 3932, 8317, 2185, 1664, 7399, 867, 2281, 4372, 7686, 10810, 2944, 7684, 7778, 10872, 5080, 8146, 455, 5155, 3081, 9405, 8476, 5345, 4777, 8534, 3610, 9022, 4012, 6069, 2411, 5313, 5439, 6719, 8907, 9880, 679, 10271, 1175, 6469, 8657, 7970, 6993, 6831, 1083, 6478, 5468, 1529, 2699, 10939, 110, 8251, 9671, 4412, 7069, 3918, 88, 6364 ]

[ [ "Smocking Orange Doily\nIntroduction: Smocking Orange Doily\nSmocking is shocking :-) I mean 'Smocking' is an art that needs patience. Just as most other arts. Well, the speciality about Smocking is that it leaves you puzzled for a while until you come to a stage where you are confident of how you are progressing. I have been trying to resume my smocking artwork for a while and have tried this an another project in this series. Thank you for stopping by and peeping into this complex yet easy project.\nSupplies\n1. 18 inches X 18 inches orange velvet cloth\n2. Needle\n3. Orange thread\n4. Ruler\n5. Pen\n6. Scissors\n7. Iron (optional)\nStep 1: Getting the Orange Velvet Cloth Ready\nThis is the first step in which I took an 18 inches X 18 inches orange velvet cloth for this project. The front and back side of the cloth is shown in images 1 & 2. I ironed it neatly.", "812" ], [ "Velvet easily looks crumpled easily and ironing is a good step to start with.\nStep 2: Pattern Marking\nIn this step I marked a square grid on the back side of the cloth with 2 cm X 2 cm lines as shown in image 1. 18 lines horizontally and 18 vertically. Then I made squares with 3 x 3 dots as seen in images 1 & 2. Each square is treated as one box of pattern to be repeated over and over. Refer image 3 for the dots from 1, 2, 3, 4, 5, 6, 7, 8 and back to 1. This how the pattern starts and end.\nStep 3: Smocking the Pattern\nAlways work on the back side of the velvet cloth. This is the step to create the actual pattern. I made a small stitch starting at point 1, then the next at 2, then 3, 4, 5, 6, 7, 8 and back to 1. Refer images 1 - 3. After returning to point 1, I then pulled the thread and tightly tied few knots as in image 5. This forms a floral on the front side. 2 such floral designs are shown in image 9.\nStep 4: Smocking the First Row\nI continued to follow the same 1-2-3-4-5-6-7-8-1 pattern for each of the square in a row. The front side work so far is shown in the image 1 and the back side in image 2 & 3.\nStep 5: Keep Smocking\nTaking care to adjust the different folds and twists, I completed the 6 X 6 rows and columns. Finally the Smocking Orange, soft, silky and smooth doily is ready.\nFeel free to reach out to me for any queries or questions!", "744" ], [ "Smocking Warmth\nIntroduction: Smocking Warmth\nYes, I understand the niceness of warm clothes in the cold season. Anything that warm, cosy and comfortable is dear in the winter season. One such is the story of the making of this 'Smocking Warmth' an idea of the warmth of love and care. My niece is just 9 years old. She is highly talented, creative and a quick learner. She always asks me to teach her something nice and new projects. Being so small, I wonder what could I teach her with easy steps and make her feel happy.\nThis 'Smocking Warmth' is a jacket I plan on gifting and teaching my niece this Summer (if Covid gives some room for kindness and warm meet-ups). Smocking is an embroidery technique used to pinch the fabric creating some intriguing patterns and designs mainly for elasticity. A completely blissful appearance.\nI haven't had time to do smocking for the past few years now. Unsure if I could try it out, I decided to give it a sincere try before I jump on a real big time project. In this project, I will share all the steps for you to achieve this hand-sewn project for a project in the future.\nStay back and learn this intriguing smocking design with very few materials and just a couple of hours.\nSupplies\n1. 19 \" X 13\" red velvet cloth (you may use any cloth, but velvet gives a much superior quality results)\n2. Sewing needle\n3. Red cotton thread\n4. Ruler\n5. Scissors\n6. Pen or maker\n7. Beads (optional)\nStep 1: Materials Checklist\nNow that you've gathered all the materials, do the following. Make sure your cloth is neat and ironed (this is optional). But a wrinkle-free cloth helps achieve amazing results. I checked on both the sides of the cloth. The red velvet cloth looks good on the right side with all the sheen and shine, The wrong side is dull and light-colored when compared to the right side. I decided to choose the right side and have the flower smocking design done on this side of the cloth.\nStep 2: Add Grid Lines\nIn this step, I choose to have 1.5\" lines marked horizontally and vertically on the bright right side of the fabric As see in pic 1, you can how the 1.5\" X 1.5\" grid lines or squares are marked on the cloth using a pen. Now, look at pic 2 to see how the squares are picket to make the cross lines. Mark a cross on one square and then leave the next. Complete the entire cloth with these cross lines,. These steps are shown in pic 3-6.\nStep 3: Stitching One Flower Design\nI started with one corner of the crossed square.", "812" ], [ "Consider this as pt 1 as shown in pic 1 and the bottom square image. Make a small stitch as see in pic 2 at the second corner. Then make the next small stitch at pt 3 which is the third corner of the square as shown in pic 3. Then a similar stitch as pt 4 which is the last corner of the square. Finally bring back the last stitch to the first corner of the square, see pic 7. Make sure you have covered all the 4 corners of the square and you return to the starting point. This is neatly depicted in pic 8.\nStep 4: Make the Flower\nThis is an important step after you've completed just one small running stitch on each of the corners of the square. In this step carefully pull the thread together. Here you see that the floral petals have to be carefully arranged. Initially it may appear messy and convoluted, but there's nothing to worry. Stay calm. Tie a knot carefully. Tug in a few times with your needle and mark a strong knots. Cut off the thread. This completes the first flower in the series.\nRepeat the pattern on all the crossed squares on the cloth. Watch all these steps as shown in the images. Row 1 is complete in the last pic shown. So far, so good.\nStep 5: Continue the Momentum\nGood job so far. By now you have been able to complete the rows and columns. Neatly stitch, pull, tie and cut the threads. With this all the 6 rows and 4 columns are completed. Here is an important step. Make sure you arrange the petals of all the flowers to look good on the symmetry. Refer the last picture to see how this is done. Neatness give a amusing finish.\nStep 6: Design on the Wrong Side\nSmocking is a technique which is pinching the fabric to create elasticity predominantly but results in an amazing design pattern. Although I chose the right side of the fabric for the main design, this pattern result in a wonderful pattern on the back side as well. Look for pic 1 above.", "694" ], [ "Handmade Embroidery on T-Shirt\nIntroduction: Handmade Embroidery on T-Shirt\nPersonally I enjoy purchasing plain T-shirts to hand embroider. I always receive appreciation and admiration while in stores for the great hand work. At times people mistake the work to be machine made. I bought this white T-shirt for a while now and was thinking of some embroidery work. I couldn't pick any design easily so left it to stay for a while until I find something that pleases my eyes.\nIn the last week, I stumbled upon this T-shirt sitting in the corner of my wardrobe waiting to be picked-up for designing. I then decided to keep it simple.\nI have upon just two embroidery stitches. 1. Chain Stitch and 2. Fishbone stitch\nIn this simple and short project I will show you the details on how to make a T-shirt just as this one.\nSupplies\n1. T-shirt of your size (white)\n2. Embroidery needle\n3. Embroidery threads (colors of your choice)\n4.", "316" ], [ "Embroidery hoop\n5. Pencil to make the design\n6. Scissors\nStep 1: Make the Design on Cloth\nClamp the T-shirt on the Embroidery hoop. Freehand drawn the design on the T-shirt as the first step.\nStep 2: Chain Stitch Leaf\nIn this step, I inserted the thread from below (pic 1) and then inserted at a short distance as shown in pic 2. Then, turned the thread around the needle and pulled the needle (pic 3). This makes a small loop or a chain and hence the name 'chain stitch'. I then continued to embroider using this stitch on the leaf border one chain at a time and then completed the entire leaf until the last image shown.\nStep 3: Fishbone Stitch for the Center Line\nFishbone stitch was used to make the center leaf line. Started at the top and made a small stitch below. Then, inserted the needle on the left side and brought it up it to the end of the first stitch as shown in image 2. Continued to work until the end. That's all. The leaf is ready. Step by step I added the same leaf around the neck of the T-shirt.\nMy T-shirt is all ready to flaunt during my next meetup with my friends and share the design with them as well :-)", "694" ], [ "Ceramic Tlle Coasters\nIntroduction: Ceramic Tlle Coasters\nThis is a perfect gift for someone special, near and dear or a cool idea for a formal gift. This ceramic tile designed coasters with fabric and jute is easy, simple and yet very appealing. Try it and share your opinion!\nSupplies\nCeramic tiles - 4\" X 4\" - Total 4\nFabric cloth - 8\" x 8\"\nMod Podge\nJute\nPaint brush\nStep 1: Smooth the Tile Edges\nAs a first step and a note of caution I made sure to sand the sharp tile edges using 60 grit sand paper. This made the edges smooth and rounded. All the dust was collected to make sure its smooth.\nStep 2: Getting the Tiles Ready\nIn this step I cleaned the tiles neatly with plain water and let it sun dry for 30 minutes. Making sure both the sides are fully dried and there's no moisture left behind.\nStep 3: Cut the Fabric\nThen I cut each fabric 3.75\" X 3.75\" and made a small cut along the corners. See image 2 for this pattern. Note that the fabric is just placed on the tile and not glued yet.\nStep 4: Adding Mod Podge\nThen, I added a generous amount of mod podge and spread it evenly on the tile upper side. The upper side it the shiny side of the tile.\nStep 5: Fabric Added to the Tile\nThen gently and carefully I placed the fabric on the tile and smoothed out the surface evenly.", "353" ], [ "Soon after, I added mod-podge on top of the fabric evenly and uniformly. Repeated the same steps on rest of the 3 tiles.\nStep 6: Enhance With the Jute Edgings\nThen, I cut 8 jute strings of 16.25\" each. Put them together and added additional mod-podge to help if stick around the circumference of the tiles. Refer images. Let it dry fully by letting it sit overnight. Repeated the same steps for the remaining 3 tiles.\nStep 7: Back Padding With Cork Sheet\nThen I took a 12\" x 12\" cork sheet. Plached it on the tile and measured the side length to 3.8\" x 3.8\". Cut it as shown. Rounded the edges and finally peeled off the paper and stuck it uniformly on the back side of the tile.\nHurrah! Finally, all the tiles are completed with the nice designs. I wrapped them neatly as a gift!!!", "744" ], [ "Pi Hand Embroidery on Paper\nIntroduction: Pi Hand Embroidery on Paper\nEmbroidery on Paper?? How does this idea sound? I have always enjoying trying different things. Learning, sharing and having a happy time with my arts and crafts projects. Instructables is one such superb platform to boost my creative energy.\nThe inspiration for this idea comes from nail-and-thread patterns on wood. Just that the nail are replaced by holes on paper. It makes like a lot easier to do the same work on more easy, safe and affordable medium as paper. A nail-and-thread pattern on wood looks amazingly intricate and create a sequel of the original pattern when symmetric geometrical shaped patterns.\nEven though the design appears simple and easy, it requires patience and perseverance as paper is not the same a fabric or any other natural material for embroidery. Having said that a careful work will fetch you great results.\nIn this project I have hand embroidered Pi on paper. Come and join me in this incredible journey to learn a simple trick to enjoy Pi Day.\nSupplies\n1. Construction Paper\n2. 5 in X 7 in Photo frame\n3. Silk threads\n4. Needle\n5. A pair of scissors\n6. Pen or pencil\nStep 1: Gather Your Materials\nThe list of materials are shared in the image 1 above. Make sure you have a good quality construction paper. A good quality photo frame takes it the next level. Silk threads of a good quality does the magic. The construction paper is choose is dark grey (looks almost black in pictures) in color and is of a great quality.\nStep 2: Cut Paper to Size\nThe photo frame I selected is 5 in X 7 in and so I cut the paper to the same size with the help of a pair of scissors. See image 1 & 2. Keep this ready for the next step.\nStep 3: Draw Pi on Paper\nWith the help of a pen, I drew Pi as a freehand drawing. See image 1 & 2. As the paper color is dark, it was not easy to see this on the photo.\nStep 4: Make Holes on Paper (Pi Outline)\nThis is the fundamental step and is crucial for the success of the project.", "95" ], [ "I have used a small needle to makes holes as an almost equidistance on the outline of the Pi image drawn on paper. The distance and the contour matters for the final looks of the project. It is important that you maintain the distance well and also follow the outline as per the design. Furthermore, as I know that is paper and not fabric or wood, so accuracy and patience is the key. With utmost precaution I pierced holes and this is seen from image 1 through 8 entirely. With this Pi image is ready. Keep coming with me.\nStep 5: Green Thread Crosses\nI picked green color as my first thread. Remember that this Pi figure is not a symmetrical pattern and so the image will not have a resulting sequel in the perfect symmetry, shape or form. I then created cross-stitches keeping 2 pairs of holes in between. This was to accommodate two other colors (pink and blue) later as planned. I continue the left arm of the Pi, then the horizontal top and later moved on to complete the right arm. As the right arm has a bend at the very end, the thread with keep on following the contour accordingly. Check for these steps from image 1 until the end. So far so good.\nStep 6: Pink Thread Crosses\nIn this step I continued to add the pink thread crosses just beside the green ones. As said it carefully working on one cross at a time and moving over from the left arm to the top one and then the right. I completed these crosses with the image 9.\nStep 7: Blue Thread Crosses\nVery similar to the green and pink crosses now I followed the blue thread crosses in the same row. Making sure the holes that are meant for this is utilized with care by lifting the needle up and down. Finally I completed the entire Pi as seen in image 6 above.\nStep 8: Adding the Border or Outline\nIn order to complete the image in its entirety, I decided to border this with a nice yellow and white shaded silk thread with a simple running stitch. This outline or border gives a nice smooth finish and enhances the entire handmade embroidery work.\nStep 9: Framing the Pi Handmade Embroidery\nAs a last step, I added this image to the 5 in X 7 in photo frame. Looks great. In reality it is hard to believe that the handmade embroidery is on a paper and not fabric. Looks rich and royal just a fabric. Ditto!!!\nWhat's your experience embroidering on paper?", "744" ], [ "Double-sided Earrings\nIntroduction: Double-sided Earrings\nCanvas + Yarn = Double-sided Earnings was the immediate title I could think of :-) These handmade earrings are simple, easy, and very much affordable within a short time span. Come along with me to learn this new double-sided earring. The leaf pattern and the web pattern. These earrings can be flipped and worn either way. The other side could also be colored differently or used as a mix and match option.\nSupplies\n1. Plastic canvas\n2. Yarn (white and yellow)\n3. Scissors\n4. Needle\n5. A pair of earring hooks\n6. A pair of circle rings\n7.", "557" ], [ "Pliers\n8. Transparent glue\nStep 1: Pattern Symbols\nWith 11 Rows and 11 Columns, there are 121 boxes in total\nR = Row\nC = Column\nR1 = Row 1\nC1 = Column 1\nR5C5 = Row 5 and Column 5\nStep 2: Get the Canvas Ready\nIn this step, I cut the canvas with 11 x 11 squares (4 total) as seen in image 2. As you can see in this image the edges are rough. To make it more elegant and neat, I trimmed the edges neatly to make it perfect and smooth. Now, image 3 shows the squares are in perfect shape.\nStep 3: The Leaf Pattern With Yellow Yarn - Step 1\nI started working first on the leaf pattern. This looks impressive.\nPattern is\nStitch 1 (Image 2)\nR11C10 -> R10C10\nStitch 2 (Image 2)\nR10C11 -> R10C10\nStitch 3 (Image 3)\nR11C8 -> R8C8\nStitch 4 (Image 3)\nR8C11 -> R8C8\nStitch 5 (Image 4)\nR11C6 -> R6C6\nStitch 6 (Image 4)\nR6C11 -> R6C6\nStitch 7 (Image 5)\nR11C4 -> R4C4\nStitch 8 (Image 5)\nR4C11 -> R4C4\nStitch 9 (Image 6)\nR11C4 -> R4C4\nStitch 10 (Image 6)\nR4C11 -> R4C4\nI repeated this pattern on the second square as well. This completed 2 squares with the leaf pattern with yellow yarn.\nStep 4: The Leaf Pattern With White Yarn - Step 2\nNow flip the image by 90 degrees and it should look as in image 2. I started working on the leaf pattern with the white yarn. This is the second half of the leaf pattern.\nThe Pattern is\nStitch 1 (Image 2)\nR9C1 -> R9C3\nStitch 2 (Image 2)\nR11C3 -> R9C3\nStitch 3 (Image 3)\nR7C1 -> R7C5\nStitch 4 (Image 3)\nR11C5 -> R7C5\nStitch 5 (Image 4)\nR5C1 -> R5C7\nStitch 6 (Image 4)\nR11C7 -> R5C7\nStitch 7 (Image 4)\nR3C1 -> R3C9\nStitch 8 (Image 4)\nR1C9 -> R3C9\nStitch 9 (Image 5)\nR1C1 -> R1C11\nStitch 10 (Image 5)\nR11C1 -> R11C11\nI repeated this pattern on the second square as well. This completed 2 squares with the leaf pattern with yellow yarn.\nStep 5: The Leaf Pattern With the Middle Running Stitch\nIn this step after completing both the yellow and white yarn as shared in the steps above, I then completed the running stitch as shared in the pattern below\nR11C1 -> R10C2\nR9C3 -> R8C4\nR7C5 -> R6C6\nR5C7 -> R4C8\nR3C9 -> R2C10\nR1C11 -> R2C10\nR3C9 -> R4C8\nR5C7 -> R6C6\nR7C9 -> R8C4\nR9C11-> R10C2\nWith this, the central running stitch in yellow yarn completed the leaf pattern. I then dittoed this on the second square as shown in image 1.\nStep 6: The Web Pattern With White and Yellow Yarn\nThis web pattern is a different one and can be used as the second side. Flip onto the other side.", "294" ], [ "Sewing Kit - Mom's Gift\nIntroduction: Sewing Kit - Mom's Gift\nI'm a 15 year old teenager and summers have been great without school but not much activities. For a long time, I have been thinking to gift my talented and artistic mom something handmade that would make her happy. More importantly I wanted this to be a surprise to my mom. I'm not so good with all the arts and crafts stuff unlike my mom. I decided to be creative and make some project from all the existing materials at home and here is one with all the steps.\nWell, I have been able to make the following (all in just one glass bottle)\n1. A pin-cushion\n2. A compartment for buttons\n3. A compartment for hooks\n4. A compartment for touch-buttons\n5. A compartment for sequins\nI had to google some of the ideas and names of the materials I used here. Never been so craft-inclined before. This was an absolutely amazing project. It did take me some time since I am barely even know 'a running stitch'. Please share your thoughts and ideas on my first attempt for my loving mom.\nSupplies\n1. A clean, small glass bottle with lid (4 inches in height and 2.5 inches in diameter)\n2. Orange colored velvet cloth (4 inches x 4 inches)\n3. A cotton cloth (4 inches x 4 inches)\n4. Needle\n5. Thread\n6. A pair of Scissors\n7. Pen\n8. Ruler\n9. Cotton balls\n10. Card paper\n11. Tape\n12. 2 small (3\" x 2\") clear plastic bags\nFor the compartments/pockets (I picked up with due permission from my mom)\n13. Pins for pin-cushion\n14. Buttons (Black and white)\n15. A packet of hooks\n16. A touch button strip\n17. A packet of sequins\n18. Loads of enthusiasm (most important) :-)\nStep 1: Making the Pin-cushion\nSince I'm a novice at all these craft projects, I will try my best to explain the steps for this instructable. I took the glass bottle which has a plastic lid. It's easy to work with and is not too small or too large. In my case it was 2.5 inches lid.", "812" ], [ "I marked a circle bigger than the lid of the glass bottle. This was 4 inches in diameter. Both for the outer orange velvet and the other cotton cloth. Refer pic 1 & 2. I placed both these cut circles inside out. I mean the good side of the cloth should be on the inside. Refer pic 3. Then, using a needle and thread I made a running stitch on the outer rim by leaving small space open as shown in pic 4. I made sure not to cut the thread. Then, I turned the inside of these circles stitched together. See pic 5. Then, I filled it up with a few cotton balls which is seen in pic 6. Making sure not to stuff up. After that I placed it on the lid as seen in image 6. Carefully I pulled the thread that was used for the running stitch. When the thread is pulled together then edges come closer and make some frills and folds as shown. This was a cute step. Finally I adjusted the shape well to look like a ball and the pic 7 shows this is done neatly. So far, so good.\nStep 2: Getting the Bottle Ready\nI made sure the bottle is clean and dry. Then I cut a card paper the same height at the that of the glass bottle. The width was also aligned to the bottle. I cut the card paper as shown in pic 2. Later I tried to insert this card paper into the bottle to make sure it fits in. This is shown in pic 3. Then, I cut another card paper of the same length and width and then cut that into two as shown in pic 4. Using a tape I attached these two small cardboard pieces at 90 degrees. This looked like the pic 5. Placed this in the bottle and it makes a cross section as in pic 6. All the 4 compartments were at 90 degrees angle.\nStep 3: Get Your Buttons Compartment Ready\nI picked up few buttons (black and white) from my mom's sewing box and added it into a clear plastic bag). See pic 1. Then I folded the bag (refer pic 2) so that it fits into the compartment in the bottle. It looks nice as see in pic 3.\nStep 4: Get Your Sequins Compartment Ready\nIn this step I picked up sequins (again from my mom's sewing box and added it into a clear plastic bag). See pic 1. Then I folded the bag (refer pic 2) so that it fits into the sequins compartment in the bottle. It looks neat as see in pic 3.", "316" ], [ "Handmade Jute Artwork\nIntroduction: Handmade Jute Artwork\nTo me Jute is a synonym for Fibre. I am so excited to work on jute projects and since the time I have read this 'Fibre Arts' contest, it has been rolling in my mind. Thinking and thinking of something to do with jute. Finally this project clicked in the last week, but I wasn't able to drive down to my local Dollar Tree for shopping as I had seen some very creative jute options out there. Before that I decide to visit Home Depot as well and did not find much options when compared to Dollar Tree and picked up this simple and cool jute cord. As I am too excited to wait to work this project, I will show you all the steps needed to make this marvelous artwork. Be assured that this is a very budget friendly project yet brings in rich looks. Hope you like it as much as I do.\nSupplies\n1. Jute bundle\n2. Glue\n3. Canvas board (12\" X 16\")\n4. Pencil\n5. 6 big white beads\n6. A pair of scissors\nStep 1: Get the Design Ready\nIn this step, I decided to have a beautiful pair of leaves and some flowers on my design. I then drew this image freehand on canvas with the help of a pencil. It is important to note not to press the pencil too hard or hard on the canvas frame as this could easily rupture the canvas and spoil it. Refer for this hand drawn in pic 3 - 5.\nStep 2: Add Jute Cord on the Design\nIn this step I carefully added glue along the outline of the leaf. I made sure to keep the jute cord straight and not to let it twist and turn.", "294" ], [ "This slowly and carefully I worked on placing the jute cord along the ups and downs of the leaf. Adding glue and the cord, then glue and then the cord few inches at a time. This did not seem very attractive in the beginning, but as I kept working on it, the leaf started getting into a great shape. I was very pleased to watch the results as seen in pic 5. At times, I had to add more glue especially at places which are not a straight line.\nI then decided to complete the second leaf as well. This was done in a very similar way just as the first leaf. It took me good amount of time as the glue takes some time to dry and then care has to be taken to keen everything aligned per the original design on the canvas.\nOn completing both the leaves, I moved onto to the mid-lines. These lines were a lot easier to work upon. Pretty straight, I cut these per the length and added one at a time. Very soon I was done with both the leave in its entirety (pic 10)\nStep 3: Making the Flowers\nIn this step, I took 5 inches of jute cord and placed it across the end of the pencil as seen in pic 3. Then, I made run the jute cord around the pencil 20 times as shown in pic 4. Then, I made a knot with the base cord on the pencil. Later pulled these rings formed with the jute cord. Finally tied up the base cord. And a flower with petals is formed as seen in pic 5. Using the same technique I made the rest 5 flowers.\nFinally I attached these flowers 3 each on either sides of the leaves and adorned these by glueing big white beads.\nCongratulations. With this my artwork was ready to go on the wall. I added a pair of handmade wooden on the sides to add some additional handmade touch.\nWasn't this a simple, budget-friendly and cool fibre art?", "294" ] ]

[ 9676, 3800, 9202, 5482, 2708, 5456, 1531, 9521, 5371, 1163, 10558, 10512, 2896, 3163, 249, 8396, 9543, 5560, 4168, 7651, 622, 1513, 3153, 5958, 4759, 3647, 4751, 3651, 9852, 7732, 2977, 3514, 6707, 3242, 2075, 1080, 8812, 2983, 8846, 3719, 4917, 9437, 2144, 384, 2998, 7983, 10069, 2969, 5168, 10874, 5824, 2438, 5927, 6459, 4866, 1283, 9792, 4370, 3960, 6236, 10295, 5245, 1595, 5038, 1092, 6023, 1075, 9145, 163, 3621 ]

[ [ "Malawi opens the first drone academy in Africa · Global Voices\nIn Malawi, 14 million people rely mainly on agriculture as a means of subsistence. In 2017, drought in the country affected more than half the population. This EU-funded project uses drones to create maps that help to locate resources such as hospitals, schools, and roads which are all vital in providing safe shelter for the population in case of a disaster. Photo by the European Union/<PERSON>, April 13, 2018, via Flickr CC BY 2.0.\nSince 2016, Malawi has stood at the forefront of utilizing unmanned aircraft systems — also known as drones — in Africa. This year, the country took a step further by opening the African Drone and Data Academy (ADDA) — the first of its kind in Africa.\nADDA officially opened on January 13, 2020, in Lilongwe, Malawi.\n“In Malawi, we strongly believe that adopting modern technologies such as drones and advanced data analysis and management techniques will help us to serve our children better,” said <PERSON>, director of Malawi’s Department of Civil Aviation.\nOpen to Malawians and citizens of neighboring countries, the academy will equip individuals with drone technology skills necessary for jobs using drones, particularly in humanitarian aid and disaster preparedness.\nGraduates will earn certificates issued from Virginia Polytechnic Institute and Virginia Polytechnic Institute and State University (based in the United States), through a partnership between ADDA and United Nations Children's Fund (UNICEF).\nThe academy plans to educate 150 students by 2020 through a 10-week course . The first cohort has already begun training and will graduate on March 18, 2020. The cohort is comprised of 26 students, with 16 from Malawi, 10 from across Africa, and women making up over half of the class.\n<PERSON>, a member of the first ADDA cohort, appreciated ADDA’s presence in Malawi:\nMy sincere gratitude to be part of the first cohort of African Drone and Data Academy (ADDA) in Malawi. Getting to interact with International people and learn new skills in Drone Technology is really exciting.", "803" ], [ "@MeloGasai @Sdhikrullahi @banza024 #Malawi#Drones https://t.co/LLpcBWjQu0\n— <PERSON> (@DeboraMtambali2) January 15, 2020\n<PERSON>, a biomedical researcher and also a member of the first ADDA cohort , shared his reasons why he's excited by ADDA's mission and work:\nEver wonder if we can predict disaster before it happens, map out breeding habitats of the world most deadliest insects (mosquitoes), monitor outbreaks and transferring medical supplies to remote areas….\nAll these are questions I seek to explore with drone…\n— Shittu Dhikrullahi B (@Sdhikrullahi) January 23, 2020\nApplications for the second cohort are already open.\nThe academy plans to partner with Malawi University of Science and Technology for a free, 2-year master's degree in drone and data innovation by 2022 — another first in Africa.\nDrones for good in Malawi\nDrones have long been recognized as an essential tool for conducting humanitarian operations in Malawi, where floods account for 48 percent of major disasters . Since 1946, the severity of flood disasters has increased, with more than 80,000 displaced in March 2019 flash floods in Malawi.\nFlooding makes already poor roads inaccessible — completely cutting off affected communities, especially in remote, rural areas. Adapting innovative technology for efficient real-time monitoring and disaster response preparedness is critical.\nIn June 2017, the Malawi government partnered with UNICEF to launch a drone testing corridor in Malawi, also the first of its kind in Africa. They set it up to research how drones can impact humanitarian work. UNICEF chose to establish the testing drone in Malawi because unreliable infrastructure has often hindered the distribution of critical medicine to clinics in remote, rural areas.\nIn November 2017, a drone called Eco Malawi delivered drugs within a 19-kilometer radius. Eco Malawi is one of five drones designed and built by 13 Malawian students at Virginia Tech University’s unmanned systems lab in the USA. Before this achievement, the 13 students had limited or no experience with drone construction.\nUNICEF has been using drones in Malawi to provide vaccines, blood transfusion kits, antibiotics and malaria drugs. In drone trials by UNICEF in 2016, drones were used to carry blood samples from babies in villages to clinics for HIV testing. These efforts have improved access to antiretroviral drugs to HIV+ mothers and children in remote regions.\nThe European Union has also supported a range of humanitarian initiatives in Malawi that feature drones as a tool for mapping, research and evacuation training related to disaster preparedness.", "142" ], [ "Climate Change Continued to Rear Its Ugly Head in 2015 · Global Voices\nNovember 11, 2015. Ethiopia is experiencing a severe drought due to two consecutive poor rainy seasons, which means that millions of people are now in need of assistance. Photo by European Union/ECHO/<PERSON>. CC BY-ND 2.0\nThis article is based on a piece written by <PERSON> for 350.org, an organisation building a global climate movement, and is republished on Global Voices as part of a content-sharing agreement.\n2015 was the hottest year on record. That’s a big headline and kind of hard to process. Behind that headline are millions of stories and statistics.\n2015 was a year that we started to clearly see the fingerprints of climate change on extreme weather events the world over. 2015 has been called a tipping point on climate change; the first year where global temperatures stayed at more than 1°C above preindustrial levels.\nBefore we dive into the difficult details, something we’ve definitely seen time and time again this year is that people have a huge ability to help each other. Whether it’s a massive cyclone or horrible floods — we have seen people going above and beyond to help those around them. One of our favorite examples after Typhoon Soudelor was a group of citizens in Saipan who provided.access to water and other essential necessities to those affected by the storm.\nHeatwave after heatwave\nThere were many serious heatwaves that happened in 2015, but few as intense as in the Middle East in July and August. The Iranian city of Bandar Mahshahr documented a heat index of 73°C (164°F). For many of the regions millions of refugees, the heat wave brought additional layers of stress.\nIndia also faced extreme heat waves that claimed over 2,300 lives. The seasonal monsoons came late and temperatures continued to climb for too long. These images caught the world's attention:\nRaging forest fires\nMany parts of the world tackled extensive forest fires this year.", "206" ], [ "In Canada, 6,000 forest fires burned an area the size of Sicily. The US had one of the most devastating forest fire seasons since 1960, with more than 11 million acres burned (that’s the size of Denmark). Thousands of people were displaced from their homes.\nThis is what it's like to drive through a gigantic #wildfire #RockyFire #Calfire #drought #fireseason #fire #firefighters\nA video posted by <PERSON> (@frostjeff) on Aug 3, 2015 at 8:56pm PDT\nToo many super storms\nIn the Northern Hemisphere, there were a record breaking number of strong cyclones, hurricanes and typhoons — 22 category 4 or 5 super storms in total. The old record was 18. See the full list here.\nFor example, Hurricane Patricia intensified rapidly and became the strongest storm ever recorded in the Western Hemisphere.\nThis is how the strongest hurricane ever recorded sounds like. Images from Melaque, Jalisco @UniNoticias #Patricia pic.twitter.com/Zw4p29gqxT — <PERSON> (@Enrique_Acevedo) October 24, 2015\nEl Niño adding intensity\nA total of 90-95% of the heat from climate change has gone into the world’s oceans and that has helped make the 2015-2016 El Niño phenomenon to be worse than ever. <PERSON>, secretary-general of the World Meteorological Organization, said, “This El Niño is playing out in uncharted territory. Our planet has altered dramatically because of climate change.”\nThis has already lead to intense droughts in Papua New Guinea and East Africa, as well as severe flooding around the world – in Paraguay, Bolivia and Chennai, India. Learn more about the impacts here.\nOne city and five countries have already declared a state of emergency due to the current El Niño, while the United Nations has deployed emergency resources to a further 10 countries. Map: 350.org\nJust how much hotter?\n2015 wasn’t just hot by a bit, it was hot by a long margin. NASA reported, “Globally averaged temperatures in 2015 shattered the previous mark set in 2014 by 0.23 degrees Fahrenheit (0.13 Celsius). Only once before, in 1998, has the new record been greater than the old record by this much.”\n15 of the 16 warmest years on record have now occurred since 2001. © Scientific Visualization Studio/Goddard Space Flight Center", "206" ], [ "Global Voices Partners With Ashoka on Citizen Media Competition · Global Voices\nFrom the revolutions of Tunisia and Egypt and the Arab world uprisings in the spring (Bahrain, Yemen, Syria), to the devastating Japan earthquake and the recent British riots, citizen media has not only reported on many of the past year's major news stories, but also been integral to some stories themselves.\nGlobal Voices is proud to be partnering with Ashoka Changemakers this year in its ‘Citizen Media: A Global Innovation Competition‘, which is supported by Google. With prizes including US $5,000 grants for citizen media projects, if making a difference through media is what you're about, we want to hear from you.\nEngaging online\nIt's clear the kind of grassroots power that citizen media is capable of, but many around the world – particularly in developing countries and marginalised communities – do not have access to the technology that makes online participation possible. Censorship too, is threatening peoples’ access to citizen and social media platforms, as governments and other authorities recognise the part that these tools can play in mobilising social movements and activism.\nCitizen media in Guinea Bissau. Image by Rising Voices on Flickr (CC BY-NC-SA 2.0).\nRegardless of these challenges, innovators around the world are still managing to produce citizen media and engage online about the issues that affect them and their communities.\nAshoka is a global organisation that since 1980 has been investing in leading social entrepreneurs – individuals with innovative and practical ideas for solving social problems.", "696" ], [ "Their Changemakers project is a global online community engaged in supporting social change work through community collaboration and mentoring.\nThe competition is open to people around the world who are transforming the way people communicate or access news and information. Winners can look forward to receiving one of four US $5,000 cash prizes in unrestricted funding to boost their projects, plus you could also be considered for an Ashoka Fellowship, which comes with a three-year living stipend and access to a network of social entrepreneurs.\nBe a Changemaker!\nEntry is easy – watch this video or see the step-by-step instructions here and get it in before September 14, 2011. Entries can be submitted in the following languages: English, French, Spanish, Portuguese, Arabic, Thai, Indonesian, Mandarin, or Japanese.\nYou don't have to be using the Internet – the competition is open to ideas that work with any communication or information technologies. Find out more about access to citizen media from Global Voices’ Co-Founder <PERSON>, in his interview with Changemakers below, or check out our citizen media outreach projects on Rising Voices.\nWe may look back on 2011 as the year that citizen media changed the world.", "696" ], [ "Tanzania reinstates controversial sanitary pad tax · Global Voices\nYoung farmers in the village of Kangagani in Chakechake Pemba, pose for a photo on October 31, 2017. Tanzania's recently reinstated sanitary pad tax disproportionally impacts girls and women in rural areas. Photo by USAID in Africa via Flickr, in the public domain.\nOn June 13, Tanzania’s Minister of Finance and Planning, <PERSON>, announced the decision to reinstate a tax on sanitary pads in the 2019/2020 budget, triggering a major debate on the impact this tax will have on girls and women.\nLast year, the same minister proposed scrapping the sanitary pad tax.\nHis recent announcement sparked public outrage, especially from women who see the tax as gender-based discrimination. The minister explained that the tax exemption implemented last year had not achieved the intended effect — to enable access to sanitary pads at affordable prices and therefore ensure “better menstrual health management.”\nBut the exemption did not reduce the retail price of sanitary pads — instead, it allowed traders to raise the rate of pads and increase their profits.\nThe minister stated that with this budget, the government will reduce corporate income tax by 5 percent — from 30 percent to 25 percent — for investors who manufacture sanitary pads locally. The purpose is to attract investors, create employment opportunities for locals and reduce dependency on imports of menstrual sanitary products.\nThe price of periods\nThe sanitary pad tax announcement comes months after the Deputy Minister of Finance and Planning, <PERSON>, hinted that it was a possibility. On April 23, the deputy minister explained that her ministry had received complaints from consumers that sanitary pads were still highly priced . She insisted that the ministry was looking for better options that would benefit both women and the government, and mentioned the sanitary pad tax as a possibility.\nEarlier this year, <PERSON>, Minister of Health, Community Development, Gender, the Elderly and Children, stated that her ministry had received letters urging the reduction of high prices on sanitary pads.\nThe average cost of having a period in Tanzania is 36,000 Tanzanian shillings or 15.63 United States dollars per year.\nThe current prices for disposable sanitary pads range from 2,000 TZS (.87 USD) to 4,000 TZS (1.74 USD) depending on the brand.\nIn response to these complaints, <PERSON> wrote letters to the Ministry of Finance and Planning and the Ministry of Trade and Industry, requesting them to direct manufacturers to reduce the prices on sanitary pads.\nEarly this month, <PERSON>, a member of parliament, requested the government to set indicative prices on sanitary pads (an average, fixed rate).", "803" ], [ "But the Minister of Industry and Trade, <PERSON>, explained that the government is only responsible for setting indicative prices for public goods and services — and sanitary pads do not fall under that category.\nMP <PERSON> then requested a sit-down between the government and stakeholders to discuss how sanitary tax exemption can reflect the needs of consumers instead of rushing to reinstate the tax:\n“Tulikutana na wauzaji/wasambazaji wa pedi, walitueleza kwamba wauzaji/wasambazaji wa jumla wamepunguza bei, tena kwa vielelezo, shida ipo kwa wauzaji wa rejareja. <PERSON> maslahi ya watumiaj wa mwisho.” @UpendoPeneza #KutokaBungeni pic.twitter.com/2H0e7PHMge\n— Clouds Media (@CloudsMediaLive) June 21, 2019\nWe met with the distributors and traders of sanitary pads in this country and these traders, with illustrations, informed us that they had reduced prices. The problem was on the retail end, that is where the pricing has not been reduced.\nIn her speech, MP <PERSON>'s said:\nThe government has considered women’s opinions, it has considered Tanzanians’ opinions, it has considered the opinions from members of this parliament and that is why the tax was scrapped. Let us go back and sit down with the stakeholders dealing with sanitary pads, from distributors, consumers and other organisations so we can figure out how this reduction can benefit the citizens. However, rushing this is not right. In 2016, I said that exempting tax alone is not enough. However, the government must come up with a system of how to protect the interests of consumers. This was my move in 2016, this was my move in 2018 when I contributed on this same issue.\nVarious parliamentary leaders also spoke against the reinstatement of the sanitary pads tax.", "424" ], [ "Why Malawi urgently needs a data protection law · Global Voices\nA demonstration in the capital Lilongwe, organized by the Human Rights Defenders Coalition (HRDC), over fraud in the 2019 elections, which were eventually nullified. Photo by <PERSON>.\nThis article is part of UPROAR, a Small Media initiative that is urging governments to address digital rights challenges at the Universal Periodic Review (UPR).\nIn Malawi, authorities increasingly require citizens to give up personal information to engage in everyday life, from using a mobile phone to participating in elections.\nBut without a clear data protection law, citizens’ rights to privacy are under threat.\nIn 2017, the Malawi government rolled out nationwide registration. Every Malawian aged 16 and above is required to register into the national register and obtain a national identity card.\nThis followed the January 2010 national registration and identification system under then-President <PERSON>’s National Registration Act. It took five years for the system to become operational on August 1, 2015.\nAccording to the National Registration Bureau (NRB), the national ID system would serve many purposes by acquiring “information about the population” that would enable “policymakers to use data-driven planning” for development and services delivery. For individuals, this would give them “proof of their nationality and personal information so that they can use it to claim their benefits.”\nVoter registration saga\nMost recently, these identification registration systems were called into question in the days leading up to Malawi’s do-over election in June, when then-opposition candidate Dr. <PERSON>, of Tonse Alliance, made allegations that underage children were being registered as part of a plot to rig the fresh election.\nOn social media, netizens posted photographs of children lining up, purportedly to be registered into the National Registration System, synchronized with voter registration. The NRB denied these allegations.\nThe Human Rights Defenders Coalition wrote to the NRB to express its concern over the matter, and the Malawi Human Rights Commission instituted an investigation.\nThe Supreme Court of Appeal ruled that in the fresh elections, only previously registered voters in the original May 2019 election could vote and that new voters were ineligible .", "779" ], [ "The decision came when then-President <PERSON> disputed the Constitutional Court ruling that ordered the fresh election.\nSIM card registration and data protection\nThe national ID process then became tied to the national sim card registration process.\nIn January 2018, the Malawi Communications Regulatory Authority (MACRA) announced a mandatory national sim card registration exercise .\nBased on the Communications Act of 2016, this required everyone with a mobile phone number in the country to register their sim card. MACRA issued a deadline of March 31, 2018, to register every sim card, after which date all unregistered numbers would stop working. The deadline was later extended to September 30, with a requirement that all newly bought sim cards must get registered within seven days.\nBy October 2018, it was estimated that up to 9 million Malawians had registered with the National Register.\nMACRA said sim registration is important for several reasons: First, it prevents a fraudulent practice called “ sim boxing ;” it helps recover stolen phones; offers protection from violent, threatening, or hateful texts; instills “discipline” for abusers; helps law enforcement solve crimes; and checks fraud and theft committed via mobile phones.\nBanks and telecoms companies operating mobile money services embarked on a “know your customer” exercise in which Malawians were required to present their national ID for all transactions. They announced that failure to present a national ID would result in freezing one’s account.\nUniversity of Malawi scholar <PERSON> pointed out in August 2019 that Malawians were being forced to give away a lot of their personal data to both private and public institutions when the country did not have a data privacy protection law. In his article, “Are Malawians Sleep Walking into a Surveillance State?” <PERSON> argued that the country needed a data protection law before Malawians were required to surrender all personal data.\nAs stated by the NRB, data collected for the National Register includes a person’s surname and given names, nationality, date of birth, and place of birth. The NRB also collects data on one’s sex, current residence, height, eye color, passport number, marital status and parents’ information. The bureau also collects biometric information, including all 10 fingerprints, a personal photograph and signature.\nHow safe was this personal data? What assurances were there that third parties would not have access to this data? Who would be held accountable should there be data breaches?\nJournalist <PERSON> observed in July that digital surveillance was slowly creeping into Malawi while hiding behind legal instruments.", "665" ], [ "Malawi: Moving on Despite the Politics of Section 65 · Global Voices\nThe phenomenal story of 19 year-old Malawian blogger <PERSON> continues to attract attention from around the globe. <PERSON> began making headlines after his appearance at the TEDGlobal 2007 conference in Tanzania, in June, where he talked about how he built a windmill using locally available resources in a remote part of Malawi where the easiest means of energy is fuel, wood, kerosene and candlelight.\nEarlier he had dropped out of school after his parents were unable to afford his tuition fees. After achieving fame through the efforts of Malawian bloggers who first wrote about the story following a news item in a Malawian newspaper, and after hitting BoingBoing.net, Digg, Reddit, and Metafilter, <PERSON> has now been featured on My Hero.\nAs videos from the TEDGlobal 2007 conference become available online, <PERSON>’s speech at the conference can now be accessed through the conference’s website, on Youtube, on his blog, and also as a download. <PERSON> has also been writing about how he is making use of the money people have been donating through his blog, using some of it for home supplies, as well as preparing to go back to school:\nWhen planting season comes, I will use some of the funds to buy seed, fertilizer and urea for my family's crops of maize, ground nuts and beans.\nI have also opened a bank account and put funds in so that my family is now prepared for medical, food or other needs and/or emergencies. I have started saving for the rest of private secondary school, boarding and university, too.\nStill in the tech realm, <PERSON> has had plenty of tech news to report about on his blog. <PERSON> announces a campaign by bloggers around the world to unite against all forms of abuse, by blogging against this vice on September 27, 2007. <PERSON> announces that the campaign is being driven by Blogcatalog. <PERSON> also informs his readers that his blog is now viewable in ten major languages, by use of a free widget, from Google Translator Widget Blog.", "830" ], [ "This makes <PERSON>’s blog now readable in Arabic, German, Portuguese, Chinese, Italian, Russian, Japanese, Spanish, French and Korean. The other piece of news <PERSON> has for his readers is the forthcoming launch, on August 29, 2007 of MyLiveSearch, which <PERSON> says technology enthusiasts have been waiting with bated breath for.\nFor <PERSON>’s African readers and others interested in Africa’s technological solutions, the most exciting news is perhaps what <PERSON> announces as the invention of a new, low cost computer that runs on solar energy.\n<PERSON> points out that over 2 billion people in the developing world live in rural and remote communities that lack basic access to information and communication technologies–telephony, computing, Internet access. In response to this need, Inveneo, a non-profit social enterprise, creates and sells highly affordable and sustainable ICTs that are specifically designed for organizations–governments,NGOs,private enterprises–that serve rural communities with vital services that include education, health care,economic development,relief and telecentres. This is great stuff! You can visit their site and make a paypal donation. Theirs is indeed a great cause.\n<PERSON> reports that the computer is already available in Uganda, for US$941, which the government there says is tax-free. <PERSON> expresses excitement about this innovation, while also observing that the cost is too high for ordinary people in rural areas, the main target of the gadget. <PERSON> ends his post by inviting the company, UK-based Inveneo Inc, to Malawi where he says it will be most welcome.\nMoving on from the world of technology, the political atmosphere in Malawi has been hyper-charged for the past two months. No two terms have so dominated Malawian discourse in the last decade as have “Section 65” and “Budget.” Section 65 refers to the section in the Constitution of Malawi which forbids members of parliament from moving away from the party that sponsored them into parliament to another party also represented in parliament without a by-election.\nPresident <PERSON>, who himself left the party that sponsored him to win the presidency and started his own party, asked the courts to clarify the section, in the hope that the courts would rule in his favor as well as that of more than 60 members of parliament who also left their own parties to join the president in his new party.\nThe courts ruled on June 15 that Section 65 was indeed valid, and tension has been the order of the day in Malawi since then.", "830" ], [ "Making Swahili visible: Identity, language and the internet · Global Voices\nTree roots cling to a 15th-century wall on Kilwa Kisiwani Island, Tanzania. In 1981, the ruins of the powerful Swahili sultanate on the island were declared a UNESCO World Heritage Site. Image by <PERSON>, January 1, 2017, CC BY 2.0.\nEditor’s note: This personal essay was written following a Twitter campaign organized by Global Voices sub-Saharan Africa and Rising Voices where each week, a different language activist shared their perspectives on the intersection of digital rights and African Languages as part of the project, “The identity matrix: Platform regulation of online threats to expression in Africa.”\nAccording to the United Nations Educational Scientific and Cultural Organisation (UNESCO), linguistic and cultural diversity are of strategic importance for people around the world to strengthen the unity and cohesion of societies.\nThis linguistic and cultural diversity propelled the UNESCO general conference to proclaim International Mother Language Day ( IMLD ) in November 1999, to be commemorated annually on February 21 annually. To bolster IMLD, the United Nations (UN) declared the International Year of Indigenous Languages ( IYIL 2019 ), to draw attention to the endangerment of the world’s indigenous languages.\nToday, there are over 7,100 languages spoken around the world, 28 percent of which are spoken on the African continent alone. Despite this, English dominates online spaces in the region. Some twenty years ago, 80 percent of the world’s online content was English-centric.", "696" ], [ "Currently, however, English content online is said to have shrunk to between 51- 55 percent.\n4/4 English\nCan we argue that more people are yearning to get online in their local languages? And is it true that 17 M people worldwide have no reason to get online, https://t.co/owzk24xch4\n— GV SSAfrica (@gvssafrica) May 19, 2020\nThe million-dollar question, therefore, is: Could this sharp drop be an indicator that people now favor their native languages online over English, considering that less than 15 percent of the world population speaks English as their first language ?\nSwahili: Coming to birth?\nSwahili is recognized as one of the official languages ​​of the African Union (AU), alongside English, Portuguese, French, Spanish and Arabic. Swahili is also the lingua franca for East Africa Community (EAC) member states.\nRwanda, an EAC member, saw its lower legislative house approve a law making Swahili an official language in 2017 – in addition to Kinyarwanda, French and English. Besides being used for administrative purposes, Swahili will be incorporated into Rwanda’s school curriculum.\nIn Uganda, the government in September 2019 approved the establishment of the National Swahili Council. Article 6 (2) of the Constitution of Uganda also spells out that “Swahili shall be the second official language in Uganda to be used in such circumstances as Parliament may by law prescribe.”\nIn 2018, South Africa, which boasts 11 official languages, formalized Swahili as an optional subject in its curriculum, starting in 2020. In 2019, the Southern Africa Development Community (SADC) adopted Swahili as its fourth official language.\nSwahili invisibility online\nKaribu Nairobi. Image by <PERSON>, September 20, 2019, (CC BY-ND 2.0)\nDespite Swahili being the most widely spoken African language, with approximately 150 million speakers – mostly in East Africa, the Great Lakes region, southern Somalia, and some parts of Southern Africa, its visibility online is dismal.\n<PERSON>, a lecturer at the Multimedia University of Kenya, states in an op-ed with the Nation, a Kenyan daily, that the absence of online linguistic and cultural diversity creates “a society with a ‘tunnel-vision’ view of the world.”\n<PERSON> predicts that most indigenous cultures end up surrendering “their identities to the ‘English way’ of doing things.” This sad reality can only be reversed if indigenous civilizations “fight to retain their identities both online and offline,” he says.\nJoin our co-founder for a Tweetchat on identity, language and digital rights in Africa starting tomorrow.\nFor Swahili, visit https://t.co/pjjxAsMAva https://t.co/pvHOpbxi6x\n— Centre for Youth Empowerment and Leadership (CYEL) (@cyelke) May 17, 2020\nBut all is not gloom and doom. There are some dedicated organizations at the forefront of promoting and developing Swahili online.", "424" ], [ "Africa’s creative industries get a half-billion-dollar boost by big banks · Global Voices\nScreenshot of Nigerian artist <PERSON> speaking at CAX Weekend in Cairo, Egypt, 2018. <PERSON> told investors that “content is the next crude oil” and must be respected as much.\nIn recent years, cultural and creative industries have played a growing role in developing economies, in terms of their economic contribution as well as their power to effect social change and cultural engagement.\nIn 2013, cultural and creative industries (CCI) generated $2,250 billion United States dollars worth of revenue and 29.5 million jobs worldwide [but] only 3 percent of these jobs came from Africa and the Middle East, according to a 2013 study by the United Nations Educational, Scientific and Cultural Organization (UNESCO) called “Cultural time.”\nFor this reason, African Export-Import Bank (Afreximbank) in collaboration with UNESCO and African Development Bank Group, developed the Creative Africa Exchange (CAX) as a “catalyst that brings together the identified assets and resources within the creative industry” to consolidate, monetize and impact African creative and cultural economies, according to the CAX website. CAX launched during the Intra Africa Trade Fair in Cairo, Egypt, in December 2018.\nAfrican creative talents from the fields of music, arts, design, fashion, literature, publishing, film and television came together for a Creative Africa Exchange Weekend in Kigali, Rwanda, January 16-18, 2020. It advertises itself as the “first continental event dedicated to promoting exchange within the creative and cultural industry in Africa,” with over 2,000 participants from 68 countries.\nOver 2,000 participants from 68 Countries expected at CAX weekend in Kigali https://t.co/28gWP2HjNB\n— africanews (@africanews) January 4, 2020\nOn the second day of the event in Kigali, professor <PERSON>, president of the African Export-Import Bank (Afreximbank) announced a $500 million USD fund “to support the production and trade of African cultural and creative products” over the next two years, New Times Rwanda reported.\n<PERSON> told guests at the event that the funds, which would build on what the bank was already doing, would be accessible as lines of credit to banks, direct financing to operators and as guarantees. He said that “while Africa had a deep pool of talent, it lacked the infrastructure and capacity to commercialize its creative talent and “reap the vast fortunes lying in wait, according to Afreximbank.", "803" ], [ "He continued:\nBecause of underinvestment in the creative and cultural industries, Africa is largely absent in the global market of ideas, values and aesthetics as conveyed through music, theater, literature, film and television. African countries import overwhelmingly more creative goods than they export or trade amongst themselves.\nHe commended Egypt’s “astronomical growth in creative exports over the last decade.” In December 2019, Afreximbank was honored at the International Fashion Awards (IFA) in Cairo for its role in supporting Africa's creative industry. <PERSON> also commended Nigeria's Nollywood industry.\nOn Twitter, artists who were attendance showed their appreciation for the gathering held at Intare conference center in Kigali:\n<PERSON>An, a singer from South Africa, called the event “amazing:”\nThe CAX weekend was amazing in Kigali, Rwanda ??\nToday I am singing at the Africa Forum Corporate Event. I love my Job!\n?Midrand, South Africa. ?? pic.twitter.com/BHBo4yCDLQ\n— <PERSON> (@Joan_Siki) January 22, 2020\nCAX Weekend organizers raved about the performance of <PERSON>, a singer from Rwanda:\nWe are still re-living some of our favorite moments from CAX weekend and this sensational performance from <PERSON> is definitely on our list! pic.twitter.com/cTqPMLTjDU\n— Cax Africa (@caxafrica) January 20, 2020\nSpeaking at the 2018 CAX Weekend in Cairo, Nigerian artist <PERSON> told bankers and investors:\nWhat we need is for you guys to really understand is that content is the new crude oil and however well you respect the oil industry you have to respect the creative industry.\nThe concluded CAX Weekend 2020 will be followed by CAX Week on the sidelines of the second Intra-African Trade Fair (IATF2020) from September 1-7, 2020, also in Kigali.", "23" ] ]

[ 4128, 3041, 5933, 9151, 3066, 2722, 3037, 6514, 9893, 9796, 7275, 2993, 4969, 9362, 5073, 8154, 6842, 11061, 10810, 5936, 5634, 10989, 6778, 10256, 1617, 5427, 2477, 5139, 1492, 2736, 11303, 7200, 6064, 11051, 2791, 9312, 8907, 6506, 3016, 5317, 9876, 8214, 4967, 2149, 6476, 7650, 9514, 11309, 4263, 7978, 10285, 6381, 4142, 97, 6318, 5590, 11370, 1371, 5641, 11281, 7924, 1355, 8068, 8555, 7524, 6192, 4632, 1885, 5439, 3398 ]

[ [ "ALIENS! Making Your Circuit Boards Into Multiuse Protoboards!\nIntroduction: ALIENS! Making Your Circuit Boards Into Multiuse Protoboards!\nI like to make wearable technology and I don't want to be limited by the shape, size, and pins made on a board if I want to use it. The DFRobot ESP32-C3 boards are a great size: SMALL, but I want them to be wearable ready too!\nUsing this technique of soldering super soft silicon wire to the pinholes in the board. from there you can get creative too and I've soldered these metal ring terminals to the ends of the wire. This means I can use croc clips, or sew with conductive thread to make my circuit! Simple and adds great functionality. You could add crock clip ends or whatever you want to your board.\nThis will make it great for prototyping many different circuits, then you just get a new board and pop it in your project after you've prototyped it. Keep this board as your prototyper! Let's check out how to do it.\nSupplies\nYou'll need the following:\n* soft silicone wire any color, I've used 28 awg gauge but I've done this with 24 and 22 as well so use the wire that suits your prototyping style\n* metal ring terminals, 16 or as many as the pin number for your board. I've used: 0.5-1.5mm2-AWG22-16, screw dia 5.3 and 0.5-1.5mm2-AWG22-16, screw dia 3.2, for these protoboards before. You can get copper color ones, and different sizes so choose what works for your prototyping needs\n* heat shrink is optional, it adds stability to the connection. I use a 50% shrink, clear for this type of circuit.\n* DFRobot ESP32-C3 I've chosen this because it's a new style board so I wanted to have a prototyping one.\nYou will also need soldering items as this is a soldering project, this might include:\n* solder iron, I use MiniWare TS80, there are some great low-cost Antex 25W ones\n* solder (lead free!)\n* tip tinner\n* brass cleaner\n* solder stand\n* helping hands are useful\n* flux\nA little about this microcontroller board: I've chosen the DFRobot ESP32-C3 for this tutorial because it's a fully featured board - with ESP32 capabilities, and it is a small size which makes it great for a wearable design. Because it doesn't have sewtabs like a more traditional or wearable purpose board, such as the Circuit Playground series, or Flora, and Gemma M0, I decided I would make it into a wearable board for my projects. Here are the pins on this board for your projects:\nPin out diagram from DFRobot : https://www.dfrobot.com/product-2566.html\nOn the product page you can read about the board, but some details are:\n* 25*20.5 mm\n* 13 GPIOs\n* li-ion battery charging management on board <- for me this is the stand-out feature from other boards. Especially for creating wearables, I usually have a battery pack, and then a charger board that needs to be secured and out of place - while being accessible.", "611" ], [ "This solves all those problems!\n* The ESP32-C3 chip supports WiFi and Bluetooth 5 (LE)\n* Programmable with: Arduino IDE, ESP-IDF, MicroPython, C, and Python\nIt also came with an expansion board so you could add a screen or other components easily, this is an interesting feature.\nStep 1: Prepare Your Wire\nPreparing your wire all at once will make soldering a little quicker. This way you don't have to stop and then strip a wire, then solder then stop etc. Let's follow these steps:\n1. Cut your wire into the correct number of pieces for your board. I need 16 pieces.\n2. After you have cut them all the same, strip the ends off one side of the wire. You can use wire strippers or wire cutters. Silicone wire when it's thin, you can also typically just use your fingertips to remove the ends.\n3. Do this for all the wires.\nStep 2: Solder to Your Microcontroller Board\nNow that your wires are prepared. Mount your microcontroller board with a helping hands or similar device to hold it securely in place. This will make soldering a lot easier.\nTwist the wire ends that you stripped earlier. To be able to push them through the small hole for the header pins, you'll need to twist stranded wires.", "611" ], [ "A Color Sensing Glove That Sends the HEX Code to a Computer Program\nIntroduction: A Color Sensing Glove That Sends the HEX Code to a Computer Program\nWouldn't it be cool to see something on our desk or nearby, a color that we like, and add it directly to our projects on our computer? Now you can!\nYou can make this hand-worn wearable that uses a color sensor to detect colors from the environment around us. Then it lights up NeoPixels with the color we scanned, and writes the HEX code to an OLED on the glove.\nThis HEX can then be sent to our computer (with touch input) - directly into what we are working on to add the HEX code for us.\nSupplies\nThe supplies I've used for this project include:\n* Adafruit Flora board or Circuit Playground Classic\n* Flora sewable color sensor\n* 4x4 grid NeoPixels but any shape will work (I've linked to the circle x 16)\n* OLED screen 128 x 64\n* wires\n* soldering or conductive thread to sew the connections\n* you'll a small piece of conductive fabric to act as a touch input button to send the HEX value to your computer\n* Felt, neoprene, or material for the glove, or a recycled glove is even more eco!\nIn this case, I won't be using a battery if you want to enable the feature of transferring the HEX code to the computer, we will need a cable to connect to our computer so we will use that for power too.\nWearable Electronics items purchased from Tinker Tailor.\nStep 1: Draw Out Your Connections\nSometimes it can be easier to follow your connections if you map them out your project. I usually start by adding all the components I need and then drawing my mappings.\nFor this circuit, we will connect:\nThe color sensor\n* Ground - Ground on Flora\n* Power - Power on Flora\n* SDA - SDA on Flora\n* SCL - SCL on Flora\nThe OLED\n* Ground - Ground on Flora\n* Power - Power on Flora\n* SDA - SDA on Flora\n* SCL - SCL on Flora\nNeoPixels\n* Ground - Ground on Flora\n* Power - Power on Flora\n* DO - to pin 10 on Flora\nConductive fabric as touch input\n* Fabric sewn or wire connected to pin 9 on Flora, pin 12 Circuit Playground\nStep 2: Check Each Component and Connection\nTo do this step by step we should add the color sensor first.", "769" ], [ "Then we can check it's working. We will do this for all of our parts, the color sensor, the NeoPixels, and the OLED.\nAfter you hook up the color sensor using I2C and the connections in the previous step, we will upload the code to our board.\nFirst, we need to add a library.\nStep 3: Adding a Color Sensor\nLet’s open the Arduino IDE and install a library to use this sensor.\nOpen the Library Manager, and search for Adafruit TCS34625.\nThe color sensing library didn’t appear when I searched - I tried searching for color sensor, which worked. Click o click Install, and Install all.\nThis library is for a slightly different color sensor so I modified the sample file slightly.\n#include <Wire.h> //include Wire.h to be able to communicate through I2C on Arduino board\n#include \"Adafruit_TCS34725.h\" //Colour sensor library\n//Create colour sensor object declaration, to see effects of different integration time and gain\n//settings, check the datatsheet of the Adafruit TCS34725.\nAdafruit_TCS34725 tcs = Adafruit_TCS34725(TCS34725_INTEGRATIONTIME_50MS, TCS34725_GAIN_4X);\nvoid setup() {\nSerial.begin(9600);\nSerial.println(\"Color View Test!\");\n//Start-up colour sensor\nif (tcs.begin()) {\nSerial.println(\"Found sensor\");\n} else {\nSerial.println(\"No TCS34725 found ... check your connections\");\nwhile (1); // halt!\n}\n}\nvoid loop() {\nuint16_t clear, red, green, blue;\n//Collect raw data from integrated circuit using interrupts\ntcs.setInterrupt(false); // turn on LED\ndelay(60); // takes 50ms to read\ntcs.getRawData(&red, &green, &blue, &clear);\ntcs.", "158" ], [ "NeoPixel Jewellery, a Colour Sensing Fabulous Wearable\nIntroduction: NeoPixel Jewellery, a Colour Sensing Fabulous Wearable\nThe video shows a part of the final project!\nThis neopixel jewellery wearable tutorial takes inspiration from a tutorial on Adafruit to make a neopixel manicure. I loved this manicure idea. Previously, I incorporated NFC chips (with an led) into a manicure, so I wanted to take a new step in a slightly different direction.\nI’ve modified items used, construction, and finishing touches.\nThe RGB LEDs will light up, and we play a sample neo light script or using a reset button, we can activate a colour sensor to display the colour that has been sensed.\nSupplies\n* Gemma M0 board\n* Neopixels I’m using a strip of neopixels, and one ‘band’ for a finger\n* Colour sensor, I’m using a Flora sensor: 1356\n* Elasticated band, 2 sizes,\n* thicker on for the wrist for the battery and board\n* thinner for the finger bands but wider than the neopixel strip (I’m using 12mm)\n* Wire, your choice, based on the aesthetics you want. I’ve got some silicone thin black wire because I love the look, movement, and feel of it. I also have some braided 3 wire to try because I like how that looks as well!\n* Croc Clips for the prototyping part\n* Battery, a 3.7V with 150 mAh LiPo or larger but check the size as you’ll be wearing it!\n* (optional) I’m adding a charger circuit to this so I don’t have to remove the battery.\n* You’ll also need basic electronics tools, a soldering iron (I love my TS80 portable solder iron), maybe clamps or masking tape, or helping hands etc, solder, sewing kit or sewing machine with threads etc.\n* (optional) Button to reset the circuit (this was added at the end as I wanted easy access to the reset button)\n* (optional) Lace to complete the look\nStep 1: The First Circuit, Gemma M0 and NeoPixels\nLet’s start with the simple part of the circuit – we will be mapping:\n* the GND to GND on the NeoPixel strip,\n* Vout to +5V and D1 on the Gemma to Din on the Neo strip.\nThis was part of my initial planning.\nI modified this to have 1 band and not 2 of LEDs. The 1 band had closer NeoPixels so more of them.\nThe final strip of NeoPixels I went with has a much closer distribution of Neos.", "769" ], [ "It can be more difficult to solder though so keep that in mind.\nStep 2: First Steps, Let’s Get Our NeoPixels to Work!\nI like to build my circuits up slowly. Component by component. This way I know exactly when something stopped working.\nIt’s an easier way to find the errors.\nFor the first part of my circuit, I’m going to get my NeoPixels working in a strip. I can test the pinouts I’m using and the board.\nI have a sample strip of 15 Neos that I typically use with croc clips.\nThe first step is to: hook up your NeoPixel strip to D1 on the Gemma M0, then hook up GND, and lastly the Vout.\nThen upload sample code.\nWait – Do you have the Library for NeoPixels installed?\nYou’ll need to have the Adafruit NeoPixel library installed to get this examples folder with sketches. For a quick tutorial on how to add an item to the library, here is a quick guide to installing Libraries with Arduino to get you up and running. [Beta Arduino 2.0.0 guide]\nIf you know how to then just go ahead and add the library.\nStep 3: Test Your NeoPixels; Run the Strandtest Sketch\nUse the default strandtest sketch that you'll have with the installed library:\n// A basic everyday NeoPixel strip test program.\n// NEOPIXEL BEST PRACTICES for most reliable operation:\n// - Add 1000 uF CAPACITOR between NeoPixel strip's + and - connections.\n// - MINIMIZE WIRING LENGTH between microcontroller board and first pixel.\n// - NeoPixel strip's DATA-IN should pass through a 300-500 OHM RESISTOR.\n// - AVOID connecting NeoPixels on a LIVE CIRCUIT. If you must, ALWAYS\n// connect GROUND (-) first, then +, then data.", "939" ], [ "Paper Cone + Color LED Clock\nIntroduction: Paper Cone + Color LED Clock\nMy granddad was an electrical engineer and he always made amazing projects. He also made clocks from time to time (no pun intended), and I've always wanted to make one myself. After countless ideas that never made it past a sketch, I finally made one!\nIt's simple to build, easy to look at and a bit unusual. Use your phone to choose the colors, brightness and dimming time, without having to take the clock off your wall! It adjusts automatically to your time zone's summer/winter period.\nThe build is very simple:\n* a few soldering connections\n* loading the program onto the controller (NodeMCU) with Arduino\n* 3D printing the frame with quick / coarse settings\n* making the paper cone and disc with a circular cutter\nPower for the LEDs and the board is supplied through a USB charger with micro-USB connector.\nUsing a NodeMCU with Arduino reduces the circuit to the bare physical minimum: the LED strip, one resistor and one capacitor, and a few short wires. Notably it does not use a \"Real time clock\" (an extra chip and battery to keep time) - instead, it pulls the time from the internet every couple of hours and uses the onboard clock in between. All settings like color and scheduled dimming are handled by using the WiFi capability of this board: it serves a WiFi access point that a mobile device can connect to and send the settings. This data is stored persistently, so even if the power is cut off, it will remember your chosen settings.\nSupplies\n(Please note, below are affiliate links - I earn a commission from qualifying purchases at no cost to you).\nElectronics\nNodeMCU (Amazon)\nRGB LED strip WS2812B 100 LED / m (Amazon)\nResistor 330 Ohm\nCapacitor 100 uF\nUSB charger (Amazon) / white micro USB cable (Amazon)\nFrame and Dial\nBasic 3D Printer (at least 120x120 mm build area) (Amazon)\n50 g white PLA (Amazon)\nSolvent-based glue (Amazon)\nThick white paper (200+ gm/m2) (Amazon)\nCircle cutter (Amazon) [must-have for clean result!]\nCutting mat (Amazon)\nStep 1: Printing the Frame\nThe LED strip is 60 cm long (60 LED at 100 LED / m), which determines the basic diameter for the frame: 60 cm / 3.141 = 19.09 cm. Unfortunately that is too big for my small 3D printer so I split the frame into multiple segments that will be clipped together.\nThe frame consists of\n* 4x identical quarter circles\n* 2x connecting clips (side)\n* 1x connecting clip (top)\n* 1x connecting clip (bottom)\nYou can print them all at once if your printer is big enough, or print them one after the other.\nThe frame will be practically invisible, so don't worry about achieving perfect print quality. Just try to make sure that there is no steps at the joints, or otherwise the paper cover would warp unsightly when attached.\nI designed the parts in Onshape.", "769" ], [ "If you want to modify the design (different LED strips, different boards etc.) then you can clone it directly from this link.\nStep 2: Assembling the Electronics\nCount 60 LEDs on the strip and make a cut before and after. The strip has a direction: the signal from the NodeMCU can only travel in one direction along the strip. Be sure to cut leave the copper pads on so you can solder the wires to them.\nOn the end of the strip cut off the copper pads. That way you can wrap the strip around the frame and there is still a small gap to feed the wires through.\nMake the following connections\n* Red wire between VIN on the NodeMCU and VIN on the LED strip\n* Black wire between GND on NodeMCU and GND on the LED strip\n* Place the capacitor between the VIN and GND on the NodeMCU\nPull the wires through the hole in the frame and solder the connections directly to the pins of the NodeMCU.\nPlace the NodeMCU into its holder.\nRemove the double sided tape backing and wrap the LED strip around the frame.\nStep 3: The Code\nBriefly\n1. Download the code from Instructables or from my github.\n2. Open it with Arduino.\n3. Choose your board (mine is a \"NodeMCU 0.9\").\n4. Go to Tools > Library Manager and add the libraries\n1. ESP_EEPROM by <PERSON>2. FastLED by <PERSON>\n3.", "611" ], [ "Classic Analog Spectrum Analyzer for Your Desktop\nIntroduction: Classic Analog Spectrum Analyzer for Your Desktop\nThis is a spectrum analyzer that visualizes 10 audio frequency bands. Although it might look like just another FFT ESP32 project, it is most certainly not! This design uses a PCB that I designed and build and although it involves an ESP32, it doesn't involve FFT. ( A digital way to determine what frequencies are embedded in a signal). The analysis of the input signal is actually done by 10 good old fashion opamp driven, band filters.\nAn ESP32 is used to host a webserver for visualization and to drive all the leds on the acrylic display.\nHere are some of the specifications:\n* 10 Opamp based band pass filters\n* Onboard Power supply 12V input/4A to onboard 5V/3.3V\n* Microphone and Line input\n* Onboard multiplexor to switch between audio signals\n* Onboard Analog switch to toggle between input signals\n* Operating panel with 3 potmeters and 2 switches\n* Onboard pre-amplifiers\n* Onboard input protection against wrong polarity and over-current\n* All hardware and software are open source\nSupplies\nYou Need the following materials.:\n* PCB buy here ( pre assembled including smt components )\n* or bare PCB without components @PCBWAY.com\n* LEDSTRIP 74Leds / Mtr ( Ws2812 or simular, Other size possible if you deviate from my housing design)\n* Acrylic 5mm black ( or other color is you prefer)\n* acrylic 10mm transparent to create the tiles.\n* ESP32 DevKit1 ( you can use other ESP32 but I wrote the firmware for this one)\n* Some wire and connectors for audio and power\n* A power switch to your liking\n* A power supply 12V / 4 A\nAlso you will need some tools skills:\n* Soldering skills to hook up some wires\n* advanced soldering skills if you decide to assemble the PCB yourself (not recommended)\n* You'll have to glue together the parts of the housing if you decide to stick with my acrylic design\n* In that case, you'll also need a laser cutter of know someone who can cut the acrylic for you.\n* And finally, you'll need to be able to install the ESP32 libaries and boards and for that you need to know your way around Arduino environment. Although, all of that can be done using some tutorials because it is not that spectacular if you have the right guidance\nAll sofware ( sketch) hardware design, schematics, pcb layout etc is available at my Github:\nGithub for Analog Analyzer\nStep 1: Assembling the Housing\nTo glue all the parts of the housing together, I used this glue: Evonik Acrifix 1R0192\nOther glue for acrylic might also work fine.\nstep 1: I started with the backplate and glued the inside spacer plate on top. This plate has a zig-zag cutout where the ledstrip can be placed.\nStep 2: Internally wire up the LED strips. Take note that you line them up properly. There can be a diviation in size and LED spacing, depending on who manufactured it.", "382" ], [ "That's why I cut my strips into sections of 6 leds and line up each one individually. The design files for the backing plate includes some engraving to help you line up the LEDS.\nStep 3: If you have the possibility, try out the leds before you glue on the top plate. You can also decide to glue the top plate later.\nStep 4: connect the connection wires to the first ledstrip because you won't be able to do this later.\nStep 5: glue on the top plate. Make sure it lines up with the other plates\nStep 6: assemble the bottom housing. I used a L shaped rules to help me line up all at a 90° angle. Don't use to much glue! If you do, you might end up with glue on the outside of the unit and you don't want that!\nThe bottom plate is not glued but attached with little screws later.\nStep 2: Placing the Tiles for the LEDS\nI used the same glue to attach the tiles, however, I only attach 2 dots of glue on the side of the tile that goes into the backplate. One dot to the left and the other to the right.\nI used a L shaped ruler to make sure the tile is place under a right angle. Also, my advise is to glue one row at a time to make sure the tiles line up. When applying glue, work in pairs of 3 or 4 because the glue hardens rather fast.\nIf you won't more visibility of the tiles when the leds are on, glacing them will help.", "276" ], [ "Talking Tetris Clock\nIntroduction: Talking Tetris Clock\nThis is my take on a large digital clock\n* Based on the TETRIS Library by <PERSON>:\n* https://github.com/witnessmenow/WiFi-Tetris-Clock\n* https://www.youtube.com/watch?v=ey2mjZ-UQNM\n* Added a MP3 / WAV player to give sound to this clock\n* Added a Webinterface to change settings on the fly\n* Added two text tickers to display your scrolling message\n* Designed a PCB that included the Audio hardware\n* Based on ESP32, open source firmware and hardware\nSupplies\n* PCB buy it here: Talking clock Main Board\n* I2S audio board: Maz98357 I2S;\n* ESP32 DEVKIT V1 30pin version\n* Highly Advisible: single row headers 2.54 to be used as socket for ESP32\n* HUB75 display 64*64( preferable) or 32*64 Use 1 or 2( preferable) displays should be a display that is supported by the library check here to see what panel to use\n* Micro SD Card\n* Speaker\n* Some wire's and a USB cable to program the ESP32\n* You also need to install software(Arduino IDE) or upload a pre-compiled version using the webinterface\nStep 1: Completing the PCB\nI had my PCB produced by PCBWay, they offer great service at a good price. You can buy the PCB at my Tindie store Most components are included. You only have to solder on the ESP32 devkit, the I2s Audioboard. I highly recommend that you don't solder the EPS32 board directly onto the pcb. Use single Row headers or a socket instead! That way, you can always remove the ESP32 if needed.\nMake sure you place the ESP32 in the correct orientation. See photo for example.\nStep 2: Using the Arduino IDE to Program the Arduino\nThere are two options to program your ARDUINO ESP32\n1. Use Arduino IDE\n2. Use the webinterface (Only Limited changed to program possible)\nThe Webinterface will be explained in the next step. First we take a look at the Arduino IDE\nIf you haven't already, you can download it here and install it.\nBut wait, we are not there yet...after installing, we need to install the files for using the ESP32 and we need to install some libraries.\nInstalling the ESP32 plugin\nStart the Arduino IDE software and use the menu to click: File->Preferences.\nA new window will popup. Look for the line that says: Additional Boards Manager URLs: and enter the following link:\nhttps://dl.espressif.com/dl/package_esp32_index.json\nNow, press OK to close the window.", "382" ], [ "Again use the menu to click: Tools->Board:xxx->Boards Manager. Again, a new window will appear. inter ESP32 in the textbox to find the ESP32 boards and press install\nInstalling the libraries:\nInstall the following libraries from the library manager. Use the menu: Sketch->include library-> Manage Libraries-> add Zipfile\nDisplay Driver (V2.05) Must be this version and not a new release!\nTetris animation\nTime library\nAudio Driver\nInstall the following libraries from the library manager. Use the menu: Sketch->include library-> Manage Libraries\nFastled Neomatrix (V1.1 )\nLoading the Sketch\nCreate a folder on your harddrive named \"mark_tetris.ino\", download the 4 files needed and save them to that folder:\nindex.h , logo.h , mark_tetris.ino and settings.h\nDownload files\nNow click on the file on your harddrive named: mark_tetris.ino. Arduino Ide will start and the sketch will open. You will see 4 tabs, 1 tab per file.\nBefore you compile your sketch, make sure you have selected the correct board. Use the menu: Tools-->Board-->ESP32 Arduino->Doit ESP32 Devkit V1\nNow you should be able to compile all successfully and you can upload it to your ESP32 board.\nMake sure the board is connected and that you have selected the correct COM port from the menu: Tools->Port\nIf you like, you can change some settings in the settings.h tab. However, the settings for your display will be done using the webinterface later. Make sure to recompile and upload again if you change these settings.\nIn case you run into compatibility problems with the libraries, this is what I used:\n* Using library FastLED_NeoMatrix at version 1.1\n* Using library Framebuffer_GFX at version 1.", "991" ], [ "Handheld Arduino LED Matrix Thermometer\nIntroduction: Handheld Arduino LED Matrix Thermometer\nMade for ART3681C - Interactive Electronic Art\nSupplies\nNeeded Supplies:\nMost of the supplies I used were in this ELEGOO Arduino starter kit: https://www.amzn.com/B01D8KOZF4\n* 1 - ELEGOO Arduino UNO R3 (included in kit)\n* 1 - DHT11 Temperature and Humidity Sensor (included in kit)\n* 6 - Male-to-Male Jumper Wires (included in kit)\n* 1 - 9V Battery with Battery Clip (included in kit) or 1 - 5V Power Adapter (not included)\n* 1 - 8 x 8 WS2812B LED Matrix: https://www.amzn.com/B088BTSPYD\n* Thin Heat Shrink Tubing or Electrical Tape\n* Arduino IDE (used to add code to the Arduino) https://www.arduino.cc/en/software\nTo add code to the Arduino, you'll need a computer nearby, and the USB cable that came included with the kit.\nOptional Supplies:\nI had leftover chipboard, Bristol board, and tacky glue to make a screen for the LED Array, but it's not necessary to complete the project. If you want to make the screen I made, you'll need a 3.5\" x 3.5\" square of any kind of thicker-pressed paper(Bristol board or cardstock are some examples),a small amount of chipboard, and tacky glue to make a frame for the LED Matrix.\nStep 1: Prepare the Jumper Wires\nTo begin, grab six jumper wires. I recommend grabbing two red, two black, and two other separate colors, choosing four colors in total. After gathering the wires, you should notice that they have some rubber bits on both ends of them. We'll want to remove some of them by pressing the point of the jumper wire into the surface you're working on and holding onto the rubber part. They should come off rather easily, without ruining the wire. Do this on both ends to one red wire, one black wire, and one of the other colored wires. On the other three wires, you'll only want to remove one of the rubber ends, instead of both. We want to remove some of these so that we can connect everything together while also maintaining a lower profile on the finished product.\nStep 2: Start Connecting the DHT11 Sensor\nGrab the DHT11 Temperature and Humidity Sensor from the Arduino Kit, the three wires that have both rubber ends removed, and some heat shrink/electrical tape. The sensor should look like a blue box with holes, connected to a tiny circuit board with three leads coming from the board. Hold the sensor so that the blue is facing you, and the leads are pointing down. In this orientation, the leads in order from left to right are Data, Power(5v), and Ground.", "769" ], [ "We'll want to connect a wire to each of the leads on the sensor. I recommend using red for Power, black for Ground, and whichever other color was chosen for Data.\nWith Heat Shrink:\n1. Add the thin-sized heat shrink to a end of jumper wire.\n2. Put one of the leads of the sensor in the heat shrink and make sure that the wire end and lead touch a decent bit.\n3. Warm the heat shrink so that it collapses around the wire end and lead, making a connection between the two.\n4. Repeat for the other two leads.\nWith Electrical Tape:\n1. Wrap a tiny bit of electrical tape around the end of a jumper wire.\n2. Put one of the leads of the sensor on the tape and make sure that the wire end and lead touch a decent bit.\n3. Press the tape around the lead and wire, making sure that the connection is solid.\n4. Repeat for the other two leads.\nOnce you have the wires connected firmly with the leads, take the other point of each wire and bend them 90 degrees. You might have to add heat shrink or tape to the other end, as the wires sit close together on the Arduino, and having them touch might cause shorting.\nStep 3: Start Connecting the LED Matrix\nGrab the LED Matrix, along with the other three wires, these being the ones where only one rubber end was removed. The LED Matrix has several wire coming from it, two sets of red/white/green wires, and one red/black pair of wires. We only care about one set of the red/white/green wires, specifically the one that's labeled Power/Ground/DIN(Data In).", "611" ], [ "Sensory Dress\nIntroduction: Sensory Dress\n3 in 1: Chameleon Safety Alarm Dress. Then learn to create a dress inspired by <PERSON> dress that catches on fire!\nHow It Works!\nGreen Button: Color Matching\n* Press to start color matching\n* Press again to lock in the current color\nRed Button: Activates Alarm System\n* Press to turn on the alarm system\n* Existing color matching continues\n* When you get close, the alarm goes off and the lights turn rerd\n* Press again to turn off\nWhite Touch Button: Transformation\n* Press to activate\n* Movement (spin) to activate lights and fire crackling sound\n* Lights turn off when there is no movement\n* Press to turn lights off\nSupplies\nElectronics:\n* Circuit Playground Bluefruit\n* Arduino Nano RP2040\n* APDS9960\n* Breadboard\n* External Speaker\n* Stemma QT\n* Pin to Pin Wires\n* LED Strips\n* Alligator Clips\n* Battery Pack & AA Batteries\n* Portable Charger Battery Pack (USB connection)\n* Conductive Thread & Needle\nOther Materials:\n* Dress/Item of Clothing\n* Fanny Pack or a Pouch and Belt\n* Regular Thread\n* Nail Polish\n* Scissors\n* Fabric/Ribbon\n* Velcro Tape\n* Erasable Ink Pen or Fabric Chalk\n* 1/8\" Acrylic Board & Glue\nStep 1: Let's Start With the Circuit Playground Bluefruit\nThe CPB will be handling the fire animation transformation.\nStep 2: Wiring\nOnce you have your code running, take a photo or write down your wire mapping so that you remember how things were connected because we will be taking apart our wiring to attach the electronics to the dress.\nStep 3: Code\nFind my code here:\nhttps://github.com/licjn/interactivedress/blob/main/CPBInteractiveDress.py\nYou can find the GitHub for this project here:\nhttps://github.com/licjn/interactivedress\nStep 4: Mark Electronics Onto Fabric\nThe CPB can be sewn onto the dress and conductive thread can replace wires so that is what I chose to do for this project to reduce bulkiness in this wearable. First, I laid out my electronics on the front side of the inner lining of my dress and marked where the electronics and wiring go on the dress with an erasable ink pen, you can use fabric chalk too. I have my LED strip along the bottom of the skirt while the CPB will be higher up on the waist. This is so that the CPB is more secure, does not experience too much movement, and is less likely to bump into things.\nStep 5: Attach Electronics to Dress\nBefore wiring the electronics, I am tacking them down in place. Thread your needle with regular non-conductive thread and attach the CPB to the fabric, looping through the pads that are unused. I sewed the CPB down at four points: TX, and Audio. Loop through each hole a few times to secure the CPB.", "769" ], [ "I connected battery pack adjacent to the CPB using velcro tape since the batter pack is heavier.\nNext up is the LED strip. I am attaching my LED strip using velcro tape. I cut 1/2 inch sections and spaced the velcro tape evenly on the strip.\nIf you don't have velcro tape you can also use a needle and thread to sew the strip down by sewing belt loops around the strip. This method attaches the LED strip but does not ensure that the strip won't slide around when you move the way the velcro does.\nStep 6: Connect the Circuit\nFor the CPB, I am connecting the circuit using conductive thread. Follow this Adafruit guide about conductive thread to learn more about working with conductive thread.\nI started sewing from the middle in between the LED lights and the CPB sewing towards the CPB pad. Once you reach the CPB pad, loop around the hole several times tightly so that the thread is touching the pad. I sewed three connections: one connection from the ground pin to the ground wire or the LED strip, one from the VOUT to the red wire, and one from the A1 pin to the signal wire. My LED lights have alligator clips on the ends so I wrapped the thread around and inside the alligator clips a few times.\nStart from the middle, sew up towards the CPB, make the connection with the CPB, then sew back down to the LED strip, make the connection with the LED strip, and sew back to the middle where you started.", "635" ] ]

[ 2951, 8670, 10221, 5744, 8294, 10377, 5005, 1262, 9743, 173, 101, 7855, 5058, 8000, 2071, 8500, 771, 2697, 9953, 167, 3359, 10969, 8382, 8994, 10951, 6013, 11404, 9844, 7678, 5526, 6756, 6222, 9109, 6554, 7870, 5579, 4719, 9817, 3390, 989, 4718, 1564, 5267, 6404, 2621, 5930, 1395, 7707, 8767, 9886, 3064, 1945, 2867, 4214, 5273, 11145, 3418, 4397, 4988, 3263, 1927, 169, 7092, 2644, 2385, 10436, 5232, 3486, 4463, 9922 ]

[ [ "First and foremost, you should get a life. What I mean is that you should go do something for yourself – pursue your interest, engage in your hobbies.\nI don't understand the need for the first sentence. \"Get a life\" is normally regarded as a negative statement, and \"first and foremost\" is a redundant cliché. Why kick it off with that, when you can turn it into something positive?\nGo do something for yourself – pursue an interest, engage in your hobbies.\nThat's much less negative, and would make a better start.\nThis pattern – peppering your prose with negative statements – continues as your paragraph goes on:\nWhat I see most of your time is spent chatting with friends. A complete waste of time. Just imagine number of people you talk to, in a single day. How many of them actually care about you?\nYou say you want to inspire, but you're stuck in the rut of a nitpicking rant.\nThe solution is simple, and it's the key to any good writing: proofread and revise. In your case, if you're trying to write in an inspiring tone, begin by getting rid of language that sounds inherently negative or overbearing:\nFirst and foremost, you should get a life. What I mean is that you should go do something for yourself - pursue your interest, engage in your hobbies. What I see most of your time is spent chatting with friends. A complete waste of time. Just imagine number of people you talk to, in a single day. How many of them actually care about you? Yes, it feels good to share about your life with friends. I love that too. Everybody does. But I generally do not discuss it with people who don't care about me. You do. Whoever you see in front of you, you'll start sharing all your life information with the guy.", "487" ], [ "I suggest you put effort into studies, extra curriculum and sports. If you have these things, it'd be fun to talk to people instead of just goofing around with them.\nYou can make further improvements by removing those first person references, which seem more condescending than inspiring:\nFirst and foremost, you should get a life. What I mean is that you should go do something for yourself - pursue your interest, engage in your hobbies. What I see most of your time is spent chatting with friends. A complete waste of time. Just imagine number of people you talk to, in a single day. How many of them actually care about you? Yes, it feels good to share about your life with friends. I love that too. Everybody does. But I generally do not discuss it with people who don't care about me. You do. Whoever you see in front of you, you'll start sharing all your life information with the guy. I suggest you put effort into studies, extra curriculum and sports. If you have these things, it'd be fun to talk to people instead of just goofing around with them.\nLet's take a look at what you're left with, after polishing some rough edges, and removing some of the fluff:\nYou should go do something for yourself – pursue an interest, engage in your hobbies. Don't spend most of your time idly chatting. Sure, it feels good to share with friends what's happening in your life. But try putting more effort into your studies, extracurricular activities, and sports. If you do more of these things, you'll probably become a more interesting person to talk with.\nI'm not saying that what we have left will be showing up on BrainyQuote anytime soon. But I think it's more balanced and inspiring than what you originally provided in this question.", "620" ], [ "(Anti)Heroes are romantic by nature. They perform heroically, passionately, in order to attain an ideal. I think the issue you might be facing here is not one of writing, per se, but of psychology.\nYou're probably judging your character. You presume that because he uses 'harsh' methods, that must be his sole definition. He can't like cake and pie? Coffee and tea? Because you use the term anti-hero, we can further presume that maybe you're only offering clarification for sake of brevity in your question, or it could also point to an underlying belief system you hold, that killing people for any reason is bad. Therefore, MC is an anti-hero.\nIf that's the case, I think the first thing you need to do is not worry about your subplot, but learn to love your MC. You have to forgive him as an author, and at least in the abstract, embrace his ideals. You aren't going to be able to convince the reader of his conviction and his passion if you're constantly apologizing for him.\nHe does what he does, because it is the right thing to do. (In his mind.) He is a murderer of murderers, sine qua non, and it is a role he is willing to accept in order to make the world a better place... for those he loves.\nThe opposite of love is not hate, it is apathy Do pardon my <PERSON>, but this is true. If you love something, if it matters to you, and it turns into something you find distasteful, that it is the inception of hate, but its core is still love. If something doesn't matter to you, you don't give a shit either way. Shoelaces for example. I doubt you have a heated, passionate feeling towards shoelaces either way.", "510" ], [ "But the naturalistic right to life, on the other hand, likely sparks you strongly, and you have very specific ideas about how that should be addressed.\nThe point here is that your MC might be angry, spiteful, vindictive, hateful, that does not mean he is evil. While you and I may disagree with his motives, he would argue them to his death, and would have very specific ideas about why what he is doing is right. In his mind, even if he recognizes his actions as questionable, he still finds them justifiable, and therefore good.\nSo if he's hateful, that's because he loves that which he hates. Hm?\nOnce you have come to terms with the MC's psychology/philosophy, likely you will see that there is not only a lack of contradiction in a love story mixed into your primary arc, it actually ADDS to the primary arc. Your reader needs to be able to relate to your MC in order to be invested in him. If he's just a single-minded assassin lacking in humanity, you're going to have difficulty pulling that off.\nBy making him more complex, by adding the fuel of a romance, you have a million opportunities to draw contrasts and metaphors between his actions and his values.\nHow do you handle seemingly contradictory subplots? The same as any other subplot. You lace it into the story. You use it to teach the reader about the world and its characters. Your use it to build empathy for your characters; to draw the reader into your story through the common ground of morality and sexuality, and then leverage it to whatever aims you desire. To humanize the MC. To deliver him. To destroy him.\nI think your subplot, as it is, could be even more powerful than your primary arc. (Perhaps not more important, or maybe that too.) I think maybe you're judging your character, and your subplot. Maybe it's not a subplot at all, but the foundation. You just need to tweak your perspective, and you may realize that it's not the plots that are contradictory...", "425" ], [ "The order of words tends to have grammatical restrictions that don't allow for you to change this. Everything else however, especially for a first draft, can/should be changed.\nThe idea behind reading aloud is that by hearings one's words read out loud, one notices what sounds good and what doesn't. For me, it takes a few days before I can see these \"errors\" in my writing, so make sure to give it some time, before returning to writing. Here a few, more or less, objective guidelines:\n* Every consecutive sentence should be of different length. This keeps the writing interesting and engaging, and excites the reader because they won't know what comes next.\n* Replacing simple words with more complex ones is good, but don't overdo it; Often, the simplest words are best. If the complex word does not serve any other purpose than to tick off the requirement, replace it with a simpler one.", "487" ], [ "Else, choose the right complex word (e.g. I ran/walked/stampeded/speeded/wandered/trudged to school). Also make sure that you don't use the same complex verbs twice in a paragraph, unless it makes more sense when it's the same (I used the word \"simple\" multiple times to underline the duality of complex vs simple words)\n* That being said, when you have a sentence starting with a conjunctive, do not allow the next few sentences start with one as well.\n* Unless several paragraphs have passed, do not use the same conjunctives (while, although, yet, and, etc.). I am guilty of this myself, and it's tough to go around this sometimes.\n* Use few adverbs (astonishingly, guiltily, happily), and instead say what a character does/scenery is, that makes it astonishing, or guilty or happy. Again, tough, but in my experience, most of my edits are because of this rule.\n* Another way to improve flow is for every sentence to be followed by a sentence that describes what the reader is interested in next. I know you may want to hear an example for this, so I would, for example, dedicate this sentence to giving you one.\nI haven't read your manuscript, so I cannot give you more feedback. But these guidelines take me very far in improving my writing.", "487" ], [ "What you're describing as \"the camera stuck to them\" is one of the fundamental elements of writing, the narrative point of view – commonly abbreviated in writing circles as PoV or POV. In the scene you've described, you've adopted a third-person PoV: \"his eyes peeped through the gap\".\nIn some writing pieces, the PoV remains locked on the protagonist throughout the story: the reader only ever learns what the protagonist experiences. There's nothing wrong with this approach but it can be quite limiting for both writer and reader; on the other hand, it can be quite realistic (very much like they're wearing a headcam!).\nThere's also the subjective/objective axis to the PoV. Is the description purely observational, or does the author reveal what the character is thinking or how they're feeling? Here's how your excerpt might look if you added the subjective element:\nHe leaned against the heavy door, his cheeks resting on its cold, smooth metallic surface, and his eyes peeped through the gap in the doorframe. His heart skipped a beat: that was <PERSON> in the creature's jaws. How did <PERSON> get there before him?\nIf it was purely the \"camera\" perspective, the reader couldn't know what the character's heart is doing. And the final sentence is an example of free indirect speech, in which the reader hears the character's thoughts.\nProbably the most common third-person narrative is the omniscient PoV, where the reader is given an overarching perspective that's not limited to the one character. This is not only useful for the reader to be able to know things that are hidden from the protagonist, but it also makes it much easier for the writer to describe what's going on. The transition is quite simple to achieve, either by describing the scene from a perspective that the previous character hasn't (at that point) got access to, or by shifting the PoV directly to another character. For example:\nHe leaned against the heavy door, his cheeks resting on its cold, smooth metallic surface.\nInside the room, the creature effortlessly threw <PERSON> into the corner, and turned to face <PERSON>.\n[The protagonist] peeped through the gap in the doorframe, just as the creature seized <PERSON> in its jaws. His heart skipped a beat.", "624" ], [ "How did <PERSON> get there before him?\nYou see how the middle paragraph has shifted the \"camera\" to inside the room? You could do this even if the room was devoid of characters: it's simply the anonymous narrator (the author) describing a location.\nA more direct way to change PoV is to view things from another character's perspective. This can be as easy as making the other character the subject of the next paragraph. Here's how such a transition might look:\nHe leaned against the heavy door, his cheeks resting on its cold, smooth metallic surface, and his eyes peeped through the gap in the doorframe.\nInside the room, the creature effortlessly threw <PERSON> into the corner, and turned to face <PERSON>. It could taste <PERSON>'s bravery already, before it had even opened its jaws. Such hopeless defiance. There was the pleasing sound of bones cracking – and another sound, unexpected, from outside the room. The creature swung round, its yellow eyes fixed on the door.\n[The protagonist] didn't stop to think. He put his shoulder to the door and pushed with all his weight. It silently, massively, opened. With a roar, he leapt...\nWhich PoV works best? What's the best way to transition to a different scene or even to a different PoV? There's no definitive answer: you'll have to try different approaches yourself. But the two best pieces of advice I can give are:\n* read as much as you can, but now with a writer's eyes: take note of the craft of the author, be aware of PoV, free indirect speech, transitions, dialogue tags, descriptiveness, etc\n* write as much as you can! Get your first draft written – don't worry too much if it's a bit messy – then go back and edit, then edit again (and again, etc).\nGood luck!", "624" ], [ "What are your quips?\nAre you making fun of writing habits that are widely recognized as bad (1), or are you delving more into your own views (2)?\n(1) Let's say you make fun of X, and some author feels like it applies to them. If they're a reasonable person, they're not going to blame their negative feelings on you. So, you won't receive any fire from reasonable authors due to any of your criticism. However, if they're not very thick-skinned, then they may chose to put down the book, just because of how much it hurts or gives them anxiety. Others may take it as an opportunity to learn and be entertained at the same time (given your book is entertaining).\nNow, let's say the author isn't reasonable? Well, then they might take out their negative feelings out on your book, giving it a poor rating and criticizing it, etc. Now, their criticism won't likely hold much weight, unless they're smart. I believe intelligence and unreasonability are negatively correlated, but that's just my belief. So, consider the first possibility; their critiques aren't going to matter a lot, people will see they're just a hurt crybaby. If they're smart however, they may formulate it well enough, or just find something else, be it a legitemate issue they exaggerate, or a made-up issue that they convincingly critique.\nSo, TLDR; your problem will be unreasonable authors, and the biggest issue they bring is lowering your ratings; their critiques are unlikely to hold much weight.", "487" ], [ "You might also have problems with authors that aren't too good at receiving criticism, who may put down your book and be more hesitant to buy your books in the future, and less willing to reccommend you to other people.\n(2) If enough authors pick up your book, you'll cause controversy. Controversy can be good or bad; it gives you publicity, and lots of people will read it and know your name; it is more likely to give your book mixed or poor ratings however.\nThing is, these issues are all only present if the readers in-question are writers themselves. I'd argue that the vast majority of non-writers, even those very enthusiastic about literature, are unlikely to care about your opinions and are more interested in how well you communicate them. I mean, you're critiquing ways people write; it's not exactly a hot topic among the laymen.\nWhat is your intended audience?\nSo, in that vein, ask yourself, who will my readers be? I think that this kind of book will have a lot more readers that are themselves writers than the typical book. The subject matter is just more likely to attract writers, I believe. So, a normal book that for some reason is likely to offend a lot of authors isn't such a big issue, as there'll be lots of non-author readers. This book however, isn't a normal one.\nSo, if (2), maybe you want to find some elements that aren't so centered around the writing craft, and increase their significance, and market your book accordingly, so as to lower the concentration of authors in the book's readership. If (1), then I wouldn't worry too much. In fact, some unreasonable, butthurt authors spilling their guts in shitty reviews might just, through the generation of memes, bring more attention to your book.", "396" ], [ "In short:\nTell the truth.\nWhat do I mean by that? Here's some writing advice from one of my favorite British authors:\nEven in literature and art, no man who bothers about originality will ever be original: whereas if you simply try to tell the truth (without caring twopence how often it has been told before) you will, nine times out of ten, become original without ever having noticed it.\n<PERSON>\nTruth, in this context, is what is true to your characters.\nTry to focus less on making the speech sound \"actually good\", and more on how the speech is going to make the receiving character feel. How are you going to achieve the main character feeling like they suck? If you're going for a serious (not comic) dramatic effect, your ammunition should draw heavily on the flaws of the \"you suck speech\" recipient.\nTake your <PERSON> quote, for example. The reason this quote is a joy to read is because 1) it's true to the characters (<PERSON>'s existence / the testing facility is built on making up facts to influence the test subjects) and 2) it contains a stab of truth: the test subject is, in all likelihood, a clone who doesn't even have a mother.*\nThe quote is untrue (which is why it's funny) and true (which is why it's sad).", "873" ], [ "<PERSON> constructed the \"you suck speech\" with the aim of discouraging the test subject, and the writers constructed the speech to be comical.\nEDIT: I'll echo <PERSON>'s answer, that the ranter, to be true to their character, could rant about what bothers them most about the other character. I'd also add that while the ranter may be annoyed and want to vent, their motives could lie elsewhere. Going back to your example, <PERSON> is probably annoyed that the test subject is misbehaving, but she's making up the \"horrible\" test results in order to influence the test subject.\nThis just makes the point that there can be many different kinds of \"you suck\" speeches and they'll have varying degrees of venting, discouraging, distraction, etc.\n*Please forgive my limited knowledge of the Portal universe--if the test subject has parents, correct me.", "494" ], [ "I think the best way to write from his perspective would be to emphasize the way what he means is quite different from the way people perceive him, so as to show that his 'bad boy' nature is, in fact, a misconception of his character.\nThere are a few ways of doing this:\nImplied through action:\nConfident people tend to take the lead without really thinking.\nFor example: say he's part of a group eating dinner and he instantly sits at the head of the table. This could be totally subconscious, but others see it as him being 'full of himself' because 'he didn't even ask!'\nAnother example might be him deciding which restaurant to go to by himself because he feels like Chinese food, without realizing that one of the people in the group is allergic/doesn't like Chinese, making him seem inconsiderate.\nPart of the way confidence can be misconstrued as arrogance is due to the way confident people are used to taking the lead and doing what they want - the assumption being, that if someone else wanted it, they'd have done it first or speak up - without realizing that introverts/timid people would have a very hard time doing it, and might just label the confident person as selfish for not asking.\nThen there's option two:\nImplied through dialogue:\nConfident people tend to speak in a manner that leaves less room for being contradicted or denied.\nAsking leading questions that imply you've already said yes to a different topic is a very confident manner of speaking - it makes it seem like the speaker doesn't believe for a second there was a chance of the word 'no' (and maybe he really does believe that!)\nNote that this is a common pickup artist tactic, which I think is an excellent topic of research when trying to write confident characters - their mannerisms might be especially helpful with writing a convincing playboy.\nExample: \"Hey, <PERSON>, what's better for you - Saturday or Sunday?\" <PERSON> asked, tapping her on the shoulder to get her attention.\n<PERSON> turned around. \"Saturday...", "425" ], [ "um, for what?\"\n\"Our date.\" <PERSON> grinned.\nAnother way of showing this is saying questions as statements, like flipping money at someone and saying 'get me a mocha latte.' - this could be a carried over from being a business man used to ordering around his secretary.\nEven more ideas - apologizing can be seen as weak, especially if done too often, and so your character subconsciously avoids it by opting for other phrases - instead of \"Sorry I'm late.\" he might say \"Thanks for waiting.\"\nand lastly:\nImplied through thought:\nConfident people tend to think in a way where failure isn't an option.\nInstead of thinking Will <PERSON> say yes if I ask her out? he might think I should take <PERSON> to [insert restaurant here] on our date. as though she already said yes.\nOr if there's rumors of a promotion in his company, he might think I hope my new office has windows. because he just assumes he'll be chosen due to being more competent than his co-workers.\nThat being said, having him be utterly unshakable would get boring quick - you should still have a couple moments/things in the story which make him crumple - lets say he can't stand up to his mother for the life of him, and docilely does everything she says even if he hates it, or say, he gets really shaken when he discovers that one of his girlfriends cheated on him for once, or the promotion went to someone who he thought he was better than in every way, ect. ect.\nMoments of weakness is what makes even the strongest characters seem human!\nOne last additional thought - confidence is a virtue people love, and a over-confidence (and womanizing) is a pretty likable flaw in fiction - it seems unlikely to me that the readers might see him as an antagonist.", "510" ], [ "I agree with <PERSON>, but beyond just passive voice (rampant in amateur writers) I see an issue of style. Some sentences read smoother than others, this is absolutely true. So if your question is merely about style, you just have to read a million books and reread your own book a million times until your words flow like syrup on a stripper's thigh.\nIf your question is really about show vs. tell, the only trade-offs there always has 'tell' on the losing end. If you want to maintain pacing, then pace it appropriately. Pacing and showing are mutually exclusive.\nIf you don't want to divulge certain information, don't. Information and showing are also mutually exclusive.\nIf it's awkward, rewrite it. If it's too wordy, use less words. All of the issues of show vs tell are writer issues, style issues, but none mitigate the value of the show.\nThe only time you should tell your reader anything is when there is no emotion or plot involved. When what you're saying is objective and a vehicle to move the story along.\n\"They walked across the tarmac.\"\nNo problem. You can tell that, especially if the plane or the characters or whatever else is what's important.\nBut not if the tarmac is made of meat.", "873" ], [ "That requires a show, not a tell, because a meat tarmac is out of the ordinary and should generate a reaction from the reader. You want your readers to feel the discomfort of their feet squishing on meat, rather than the familiarity and assurety of rough concrete. If you merely tell them it's uncomfortable, it has no impact.\nBooks do not merely tell a story. They evoke them, in ways that not even movies can attain. Movies can impact you through visuals and sounds. You can see a character react and know what they're feeling. You can hear the low, stomach-churning pitch of <PERSON>'s spell razing the amassed soldiers. The music swells, the skies darken, and the wave of magic crashes into the front lines, countless bodies like blackened matchsticks, violently tossed asunder or carried along in its horrific wake.\nA book is internal. You can know the minds of the characters far more than you can with any other medium, and you would be remiss to lose that opportunity to invoke the readers' emotions to your aims. The best books, like the best movies, will make you cry, rage, yearn, laugh, worry, whatever.\nBut you can't tell your reader to cry. You gotta weave magic for that.", "999" ] ]

[ 10709, 4022, 8451, 225, 9497, 8860, 3679, 4185, 8844, 3478, 8105, 7826, 9477, 5299, 3531, 6982, 9837, 997, 10563, 4454, 2425, 1266, 2058, 10423, 2813, 5300, 8023, 2766, 10117, 5004, 6986, 1636, 3926, 4783, 1971, 8876, 6917, 6784, 828, 4532, 382, 9663, 7485, 6392, 8759, 5554, 6902, 9496, 5605, 5363, 11000, 7649, 9753, 10652, 4768, 10518, 7531, 4156, 8398, 9200, 606, 7504, 6468, 3462, 7375, 9177, 11060, 8450, 8917, 3409 ]

[ [ "I recently received a copy of The Supreme Commanderfrom my 'dealer' and have been playing it in any spare moments I have. I wanted to write a review because I like this game and think it has so much to recommend it.\n1. The Map\nThe map really works for me. It is relatively uncluttered and there is a neat option of playing it on a single map if you are limited for space. The hexes are a good size (at least on the double mapper) and the text is clear - even though my eyesight is starting to tell me I probably need glasses.\nThere are four types of land terrain which creates some interesting interaction with the seasonal effects of mud/snow/clear. I wasn't personally convinced that the polder (described as marsh in the map legend) of the Netherlands would be easier to attack in the snow turns,(no +2 for the defender),but this is a very minor quibble.\nTerrain modifiers are cumulative too which is unusual for a wargame but I think is spot on at this scale. There are boxes on the map for placing air and naval units which are assigned to fronts rather than individual airfields. I wasn't sure if I would like this but the requirement of a friendly city in range of the target hex not only makes perfect sense but also allows for a very elegant mechanism as each city will only allow two air units to participate in the combat making it very hard to dominate the air in enemy territory.\n2. The Rules\nThis is the first wargame I have ever played where 99.9% of my answers to questions are in the rulebook. Having recently played Carthage: The First Punic War, I can't tell you how happy that made me. There is a logical flow to them and the specifics are easy to reference. It is also quite short for what it delivers in chrome.\nAs is usual for GMT now there is not a separate playbook and I did initially think this might be an issue. This is an ETO after all! In fact, I was able to read the playthrough (illustrated), skim the rules and get playing within about half an hour - literally. It probably helps that I have played <PERSON> Third Reichand Axis Empires: Totaler Krieg!because there is definitely some overlap there, but the real genius - in my view - of <PERSON> is that he has taken the best of those systems and made them even better.\n3. The Combat\nThere is a CRT table but it is based on force differential rather than odds. Included in it are a number of factors linked to terrain, time of year, involvement of HQ's, air cover, technology levels etc... Advances are strictly limited by ZoCs which is again unusual but also seems to work. This is compensated for by a second round of combat for stacks including armour which can be devastating.", "993" ], [ "At the highest odds there is still a chance that the attacker will suffer casualties. I like this because nothing in life is risk free. Divorce has taught me that (if very little else).\nNaval combat is enhanced with the ability to build decoys if your technology levels reach certain points. This means that when you commit your ships to counter a threat you might find them shadowing ghosts while your opponent steams through the Channel. Subs can be used against ships or, if U-Boats in the North Atlantic, to reduce Britain's MSP's (basically the currency of the game). Bombers can be used to strategically bomb cities but their effect is limited by the MSP value of the cities.\nA very interesting feature of ground combat is that only one stack can attack at a time. Other stacks surrounding the enemy will lend a modifier (+1 per stack), providing they are not adjacent to an enemy themselves. Attacks are also declared in advance with markers. No - 'oh, I think I'll attack here now I see that attack went well'. I suspect some won't like this - I did.\n4. The Chrome\nWhat I really love about this game is the simplicity with which it delivers chrome. For example, diplomacy uses a table, very similar to JP3R. A single roll with very clear modifiers and the ability to use MSP to influence it affects how neutrals feel about the two sides. Unsurprisingly events such as declarations of war can also influence it.\nTechnology advances are implemented through another table which, again, is easy to understand. These are very expensive to purchase although most major powers start with an edge in a particular areas (not Italy though). It offers combat, decoy options and eventually movement bonuses. A great twist is that if you race ahead it costs your opponents less MSP to catch up.\nThere are also historical events such as the Winter War. These are dealt with in a couple of lines in the rules but are easy to follow and have a real impact on the game.", "449" ], [ "I am a big fan of OCS and BCS. Recently a BGG user asked me to compare the two, so I have. After writing my thoughts down I thought it might be worth sharing with others. Gnarled veterans of both systems feel free to correct/point out any errors. I'm not being precious about this. I have tried to focus on the key similarities and differences. I'm not so interested in discussing the whys and wherefores.\nSupply\nOCS uses both trace supply and on-map supply. Trace supply is a very basic level of supply where, Combat units must be able to trace a path to a supply source or they may lose steps/whole units. This supply source is usually a port or a map edge hex. Rail connections, divisional HQs and 'extenders' are typically used to extend that range.\nOn-map supply is a very literal form of supply and uses Supply Points (SP). These are counters that are physically moved around the map using mules/trucks and air transport. Supply Points are required if you want to attack, re-fit your aircraft, use barrages or keep units that are cut off from trace supply from losing steps. It is not required for units to defend themselves but their strength is halved if they don't have/choose to use it.\nIn BCS, there are no supply points to transport around the map. Instead you need to maintain a Main Supply Route (MSR) - basically a line of supply between the map edge, the combat trains (effectively supply hubs - one per formation), and finally to the HQ's. Failure to maintain the MSR leads to step losses and significantly reduces the ability of the formation to activate fully/at all.\nAircraft and Artillery\nIn OCS aircraft and artillery units are physically represented on the map (although sometimes planes have off map bases too) with counters and specific rules about how, when and where they operate. With aircraft you can do a variety of missions including fighter sweeps, interceptions, bombing, transport troops etc...\nIn BCS this is far more abstracted. There are no artillery or air units. Instead both players will receive artillery points.", "449" ], [ "Artillery points are either inherent to an HQ’s or can be assigned from High Command. They are used to either kill or suppress units, there is no such thing as ‘disorganised’ status for units (always shortened to DG’d) as there is in OCS and SCS.\nAir points can be used by any Allied formation and act in a very similar fashion to artillery points. There is no Luftwaffe because the results of their efforts in this campaign were so negligible. In fact there is no air to air or ground to air combat at all.\nMovement\nMovement in OCS is far more varied than BCS. A unit can be in a number of modes that determine when and how far a unit moves, e.g. reserve mode, strat mode etc, move mode etc... These are shown by either flipping the counter or placing a marker.\nWith BCS there aren’t any modes. A unit can be either be flipped to its move side, which allows greater movement or to its deployed side. The deployed side may change how the unit moves, e.g. tracked PZG can switch to leg movement (going on foot) or improve its ability to fight.\nCombat\nBoth OCS and BCS give their units an action rating (AR) which influences how well they fight. For OCS the AR is probably more influential.\nIn OCS a combat starts with a 'surprise roll' which is modified by the difference between the AR's of the two units and can influence a combat by up to six column shifts in favour of either the attacker or defender.\nThis makes it less attractive to those that regard wargaming as an accountancy exercise but is great for those that look for a bit of unpredictability. It then uses a series of modifiers to determine the result. As well as the surprise roll, the usual odds (3:1 etc...) and terrain are a key determinates in the outcome of combat.\nIn BCS the combat is far more predictable and uses a range of modifiers as you would expect based on the AR of unit involved and terrain. Terrain however is nothing like as important for determining the outcome as OCS. There is however a wider variety of attacks a unit can do in BCS and therein lies much of the fun of the game, e.g. engagements (ARM v ARM), regular attacks (assaults), shock attack (ARM v INF) etc...\nStrength of a unit only matters in ARM vs ARM. It is not included on Infantry units, which will lead to a bit of head scratching when you look at those counters for the first time. No odds tables are used at all. Radical stuff!", "100" ], [ "Image Courtesy of Kingmaker961\nThis review continues my series of detailed reviews that attempt to be part review, part resource for anyone not totally familiar with the game. For this reason I expect readers to skip to the sections that are of most interest.\nIf you liked the review please thumb the top of the article so others have a better chance of seeing it and I know you stopped by. Thanks for reading.\nSummary\nGame Type – Block Wargame\nPlay Time: 60-120 minutes\nNumber of Players: 2\nMechanics – Card Driven, Dice Rolling, Hand Management, Point to Point Movement, Simultaneous Action Selection, Secret Unit Deployment\nDifficulty – Moderate (Can be learned in an hour and takes a few plays to get to grips with)\nComponents – Good\nRelease – 2010\nDesigner – <PERSON> - (Gettysburg: Badges of Courage, Liberty:\nThe American Revolution 1775-83, Shiloh: April 1862, Victory: The Blocks of War, Wizard Kings)\n+\n<PERSON> - (Debut Title)\nOverview and Theme\nIf there is one gaming genre that I have not really engaged with in my 20 years in modern board gaming, it is Wargames. This is due to two main reasons; not having an opponent or gaming group that likes this sort of thing and the fact that Wargames have always seemed very complicated to me and the worry that I was not up to them.\nSo when Columbia Gamesoffered me a chance to learn and review their game, Julius Caesar, I was cautiously in favour of the idea. I had reviewed for them last year and I was pleasantly surprised at what I found (as economic rail games are not normally my thing). That game proved to be something of an entry-level or 'light' game in that style, so perhaps Julius Caesar would be something similar in the Wargame genre?\nI knew roughly what I was getting myself in for; a block wargame for 2-players that would require 'stickering' with the inclusion of 'fog of war' (not being able to see the nature of enemy units until combat is engaged). The theme involves Rome's most significant civil war with both sides being led by the namesake of this title and <PERSON>, during the time of 49-45 BC. I'll add that I know little of this particular conflict.\nDespite having reviewed over 500 games now and racking up 20K+ plays I was nervous about reviewing this one.", "299" ], [ "Why? Simply because this is not in my wheelhouse, this is something quite new to me and this may limit my effectiveness and accuracy in reviewing a game of this type.\nBut with that comes a silver lining too. If you are anything like me and have never given a <PERSON> a chance...well this review could be quite instructive. I will bring a fresh set of eyes to the genre and can give a 'greenhorn' perspective on the experience.\nSo let's get down to it. Lose the toga, don some armour...we fight for the future of Rome!\nThe Components\nIn my one experience with Columbia Games, they tend to offer good wooden blocks and an acceptable map to keep costs down. Let's see what <PERSON> has in the production stakes.\nBoard – The board is a nice big 6-panel affair that depicts the Mediterranean Sea and surrounds. Naturally Italy is center stage and the map extends from Spain and north-west Africa to Egypt, Jerusalem and Persia minor in the east.\nThe map is adorned with various lines representing roads that link Cities and the Mediterranean is dissected into various sea zones.\nIn keeping with what I have seen fromColumbia Gamesso far, the board is not of the high-quality mounted affair as expected from Euros and thematic titles, here we get a decent level of cardboard thickness but one that can lose its shape and needs some bending back in spots to get it flat when acquired new. I don't have a major problem with this if it helps to keep the cost down and most Wargamers use a perspex sheet anyway to keep boards like this in place.\nI like the colouring of the map, with the water featuring a nice blue and the land featuring muted greens so as to not make it garish and to give it that map-look. Elevations are subtly depicted and the greens in the north are deeper than Northern Africa as they should be.\nA Round\\Year Track is located in the top left corner and various icons adorn the map to reflect City Status and Levy locations of note.\nImage Courtesy of Kingmaker961\nBlocks & Stickers – The game offers up really nice wooden blocks in two different colours to represent the two sides in the conflict. The blocks offer a really nice thickness that makes them lovely to hold and touch and the size is the same if I remember correctly as those used in .", "92" ], [ "All of my reviews aim to offer a brief overview that allows people to get a good feel for what the game may offer them. I feel that other reviews can be sought if detailed game mechanics is what you are after.\nSummary\nGame Type - Board Game (Conflict)\nPlay Time - 60-90 minutes\nNumber of Players: 2-4\nMechanics - Conflict (Dice based), Risk Style, Mission Cards\nDifficulty - Moderate (takes a few plays to iron rules out)\nComponents - Very Good (Everything is excellent except for the flimsy monolith, thin cards and inadequate insert tray)\nIn Nexus Ops, each player finds themselves in control of an immoral corporation. Your aim is to ruthlessly exploit the resources of yet another distant moon discovered by your scouts. But you are not alone as other corporations are also aware of this newest location. The mineral Rubium is highly prized and you will do whatever it takes, including using alien force (and forces), to disrupt and destroy your opponents and make another fortune!\nNexus Ops is a war based conflict game in the same vein as RISK. The key difference though is that controlling areas is not the key goal. Instead each corporation has its own secret agendas that if completed will earn them victory points. These take the form of Secret Mission Cards and can vary from controlling certain terrains to destroying certain creatures and winning battles in a given way.\nThe first striking element of Nexus Ops is the units that each corporation can control. These are made of a clear plastic and they glow under an ultraviolet light – cool indeed! They include humans, Fungoids, Crystallines, Rock Striders (think giant spiders), Lava Leapers and Rubium Dragons. Each corporation has the same units to deploy and only the colour varies but this doesn't detract from the game in any way.\nThe board itself uses a range of hexagonal tiles that will form 2 rings around the central Monolith before each player’s Home Base is attached. The set-up is dependent on the number of players and this combined with the random draw of tiles featuring different terrains will ensure that each board will offer a unique experience. The set-up of the board being dependent on the number of players is also crucial as it allows for equidistant player placement. Unlike Risk and other games of this nature, no player will have their back to a protected wall. This is a major plus.\nThe Monolith is a 3D tower of sorts and it offers great rewards for any corporation controlling it during the game. These take the form of Energize Cards and 2 of these will be earned by a player if they control the Monolith at the end of their turn.", "336" ], [ "These cards typically improve movement and combat abilities and are a great way to surprise the enemy. For this reason the Monolith makes for a continued conflict point throughout the game and gives the game a 'Capture the Flag' type feel.\nEach hex of the moon also receives an exploration token. When a corporation moves units to a new hex, these tiles are revealed. Some will feature a new mine, others will feature units that you can add to your forces and some contain a smaller mine but have a unit as well. These exploration tiles are the early aim and ensure that conflict develops quickly - there is no hanging around and little down time in Nexus Ops!\nThe aim of Nexus Ops is to control the mines scattered throughout the moon. Each home base features 3 mines, but many more await discovery. Mines yield Rubium (1 or 2 in the unexplored regions), which is used to purchase new units and these are used to control further mines and engage enemy corporations in combat if necessary (read as highly necessary).\nEach turn allows a player to buy and place units (always in starting mines), move, explore, fight and finally collect income based on the total value of all mines within a corporation’s control. This is the nuts and bolts of Nexus Ops and each player receives a Corporation Template that outlines each units cost, attack and defence ratings, any special abilities and the effects of each terrain on each unit. It looks and feels a lot like Axis & Allies for anyone familiar with that game. A nice feature is that each player can draw a new Secret Mission Card at the end of each turn and this can result in a player holding 3+ cards at any one time. This gives the players' options and a good chance to keep up with the lead.\nThe combat is simple and like any game a heavy dose of luck is needed. For each unit a single D6 is rolled. If the number rolled is equal to or higher than the attacking unit's 'To Hit' number then a casualty is inflicted. The enemy can choose to lose any unit involved in the battle as a casualty. Each unit attacks in order from the most expensive down, so the composition of a player's attacking force is important.", "349" ], [ "CONCORDIA Published by PD verlag Designed by <PERSON> Price on Amazon: £49.00\nCONCORDIA was first published around 2014, and my thoughts on playing it now that it has been launched again are \"How the heck did I miss this Gem first time round?\" There is a solid Ancient Roman theme that is adhered to throughout (with perhaps a little leeway here and there) and you get the feel that this is a deliberate proposition and not just chrome added to a game mechanic.\nIt is played on a double-sided board, the general side to use is the World according to Ancient Europe. The slightly harder game is played on the flip side, which is an expanded Italy. Both maps show the available routes - brown for overland and blue for sea travel - that the player's Colonists use for exploration. These routes are made of small square dots, but no matter the length of the journey the distance between two Cities is always just one movement point. Players have as many MPs as they have Colonists on the map.\nEach player has their own colour components, meeple Colonists and ship Colonists, plus a set of colour coded starter cards.\nThe game's components are impressive in number. In design they are regular, basic meeples (ships, people, wheat, houses etc), a deck of cards, resource tokens, and cardboard coins. That's not a bad thing in any way, shape or form. They are easily recognisable for what they represent, they are made of coloured wood - each resource being a different shape and colour.\nSo I guess this is one time when the old chestnut 'colour me impressed' is actually true and of value.\nSo let's take a look at the rules, the mechanics, the lifeblood of every great game.\nRule 1. Play a card from your hand and do what it says on it.\nRule 2. Refer to Rule 1.\nThat's it!\nThere is an amount of random in CONCORDIA, but only in the setup. What there isn't is a lot of (or any) luck; what happens in the game depends entirely on the card/s you play and the actions you take.\nIt isn't cooperative, it is challenging and competitive, and there are several ways to frustrate your opponents without ruining their game.", "336" ], [ "I really like that you can cause minor upsets that mean opponents may have to rethink their strategy.\nFrustration Fact: You only have a finite number of resource spaces on your player board, so it is often that you find opponents playing cards which create resources that you cannot take, even when you need them. In fact it's fun to play a card to hand out free resources when you know darn well that another player who desperately needs that resource cannot take it. Resources can be traded/sold by playing a Mercator card but may never be discarded. To gain more space for resources on your player board you have to get more Colonists on the board - each Colonist takes up one resource space.\nCONCORDIA has elements of man management, resource management, card management, deck-building and area control.\nMan Management: You have 6 Colonists each. 3 sea and 3 land. Once placed on the board they can be moved accordingly by the previously mentioned tracks. Each Colonist on the board gives you one MP that can be used on one or many Colonists.\nResource Management: Brick, Food, Tools, Wine and Cloth are all needed, usually a Brick and another resource (depending on what the city trades in) to build houses in different cities (each player may only build one house per city.\nCard Management/Deck Building: Each player begins with their own set of 7 cards - each set being the same - and then buys cards from the display. Buying cards seems expensive at first as the cost is in resources (which are already quite difficult to gather) but you really need to boost your personal deck as many of the cards available will boost your score.\nWe really like the fact that although you build a deck by buying cards you get to choose the cards you want to play, no hoping the right combination will come along. However, once played the card stays played until you play the Tribune card. Playing this card counts as your turn but it does return all played cards to your deck.\nArea Control. Playing a Prefect card gives either a cash bonus or, usually better still, all the resources from his houses in one of the Provinces (as long as the Province is still providing). If the player also has the Praefectus Magnus card - this passes round player to player on being used - in which case the player receives one extra resource.", "629" ], [ "Europe in Turmoil (EiT) has been out for a couple of months but it hasn’t yet had a written review. I think the game deserves more attention so I will attempt a brief review.\nI have only played the game twice so far, so I am only a novice with the game but I can offer some initial impressions.\nGeneral description:\nEiT is very much based on GMT’s Twilight Struggle (TS) and 1989. That is no bad thing, Twilight Struggle has been a highly regarded game since it was released in 2005, GMT has kept it in print and it is listed as one of their best sellers of all time. So it is a good heritage to base a design on.\nThe first time designer, <PERSON>, has closely followed the system of those two games for the basic game engine. What he has added is the theme of the game, more than anything for this system that is a question of the cards and their events. For EiT and its predecessors it is the story created by the historical events, as much as the basic play, that really makes the game.\nThe interesting decision <PERSON> made is in the struggle that he has chosen to represent. You might expect a 2 player game about the lead up to War to represent the players as the Central powers and Entente powers. That angle probably requires a multi-player game where each country seeks to advance it’s own cause through alliances. Instead EiT casts the 2 players as the forces of Authoritarianism vs Liberalism.\nSo the Authoritarian player represents a range conservative cause across Europe, from the strict monarchism of a ruler like <PERSON> to the religious and cultural conservatism of peasants from France across to Russia. The Liberal player represents ideas such as parliamentary democracy, new artistic expression and the rising power of industrial workers in central and Western Europe.\nThe point of the game is not to build an alliance of nations to win a coming world war. The point is to win an early version of the culture wars, to shape Europe down one path or the other. The game can end with the calamity of the World War but it doesn’t have to. If the game does end because war breaks out then the outcome of the war will affect each players’ final position. An Entente victory in the war will aid the Liberal cause as a Central Powers’ victory will aid the Authoritarian cause.", "993" ], [ "Think of the war, if it happens, as an extra big event in the game, like any other event it changes the game situation and will benefit one player but it does not simply determine who wins the game.\nWhen I first heard about EiT and its focus I was not sure. The period very much appealed to me but I was not sure about the nature of the struggle it represented. In TS it is not hard to see the struggle as the USA and the USSR vying to be the number one world power. The contest may have been expressed in ideological terms and many of the flashpoints may have been about very local issues but primary driver was two empires in conflict. As a player you can identify who you are.\nIn EiT each player’s identity is not so specific, you represent a range of causes with some shared ideology but no single or central driver. None the less the struggle was very real. Think of the current era, commentators look at Brexit in the UK, the election of <PERSON> in the US and the rise of Right wing parties in Europe as having common roots in populist politics. No one is implying that there is a single country or group driving these events but the culture struggle is common and events in Europe, the UK and the US do affect each other.\nOnce I started to play EiT the player role worked for me. Playing the Liberal side I could see myself as representing Silesian coal miners looking for Socialist change, Viennese intelligentsia promoting the art of <PERSON> and the psychology of <PERSON> and Russian democrats trying to modernize their government. Ranged against me were the forces of Chancellor <PERSON>, the ossified <PERSON> dynasty and the Russian Orthodox Church. All disparate forces but playing it as a binary contest works.\nFor me, EiT succeeds in capturing the flavour of Europe in the decades before the First World War. It was complex world, partly locked in Europe’s past but also sign posting major changes that would drive the coming century and in many ways it disappeared forever with the First World War. Decades ago <PERSON> set out to show this in her book The Proud Tower. EiT takes you back to that world and immerses you in the issues of the day.\nGame play\nEiT plays very smoothly. Even though it uses a tested engine, a game that has 110 card events can suffer if it they are not well designed and tested.", "72" ], [ "This review continues my series of detailed reviews. I have tried to cover every aspect of the game and as such you may prefer to skip to the sections of most interest.\nImage Courtesy of chaddyboy_2000\nSummary\nGame Type – Board Game\nPlay Time: 90-120 min\nNumber of Players: 2-4 (Best with 4)\nMechanics – Area Control/Influence, Card Drafting, Hidden Planning\nDifficulty – Moderate (Can take 2-3 plays to fully comprehend rules and the basic strategy)\nComponents – Excellent ++\nDesigner - <PERSON> - (Colonial Diplomacy, <PERSON>, Heads of State, Triassic Terror)\nOverview\nWars of the Roses is an ambitious game in that it tries to capture a tumultuous time in English history that was far more than straight forward warfare. So to be true to the period the game needs to incorporate not only military conflicts, but the political nature of the day, the importance of the church and the key role of economics.\nOn top of all that, it is crucial that the game also allows for intrigue and surprises to occur if it is to truly reflect the historical nature of the time and give the game that extra something.\nI am happy to report that Wars of the Roses does this wonderfully well and the combination of its physical design combined with its mechanics makes it something of a Euro/Wargame hybrid.\nBefore I continue it has come to my attention from reading some forum pages that there may be some confusion between this title and another game called Richard III: Wars of the Roses, by Columbia Games.\nThe game being reviewed here by Z-Man Games is in no way connected with the game from Columbia. They are both independent titles, which interestingly enough, were released within 3 months of each other.\nThe Theme\nWars of the Roses is set in the period of English History dating from 1455 - 1487, which is referred to as 'The Wars of the Roses'. It was a period of time in history when two great houses were fighting for control of England and control over who sat on the throne.\nMilitary conflicts were common but political infighting was the real 'lever of power'. The church was heavily involved and the houses were forever trying to convince powerful nobles to support their cause.\nAs key figures in this struggle, the players take on the roles of a key personality aligned with 1 of the 2 houses. <PERSON> (<PERSON>) and the Earl of <PERSON> (<PERSON>) represent the House of Lancaster (<PERSON>). The Earl of <PERSON> (<PERSON>) and the Duke of Gloucester (<PERSON>) represent the House of York (<PERSON>).\nOn a personal level I had no real understanding of this period in history before learning of the game. Whilst I am an avid student of history, both ancient and modern, this time period never did it for me.\nIf you are like me however, do not despair, as it will not result in you enjoying the game any less. It is very easy to play the game and remove yourself from the theme, simply playing as part of a team (at least initially) and using the mechanics to go about acquiring your assets in order to turn the screws on your opponents.\nOn the other hand, if you have a good knowledge of the period, or like to immerse yourself in the theme of a game, it allows you to do that too. You can amass large forces, control great Royal Castles, make a swift attack on the Midlands, control the Bishops or a region or dominate the Shipping Lanes.\nI guess what I am trying to say here is that the game is fairly accessible.", "299" ], [ "If you have no interest in the setting of the game, it can still be enjoyed on a 'game only' level. But there is plenty here for the history buffs and theme demons. Indeed the rulebook and Planning Screens offers great detail on the background to the conflict for those that want to know more. I must admit, the game has given me a much greater understanding of the Wars of the Roses - so yay to that.\nComponents\nA word of warning (it's a good warning) - you will need to start working out if you expect to carry the box for more than 2-3 metres. This baby is chock-o-block full of gaming component goodness. Not only is there lots of components, but they are quality components. This thing weighs more than a 12 month old baby but thankfully it isn't as messy.\nThe Board - The board is a big old gorgeous creation that depicts England. The country is divided into 6 regions. Each region is referred to as a county but for game purposes they really represent an amalgamation of counties. Each county has its own colour to help determine one from another easily. The colours are muted in tone and not garish (something that many a modern board has done of late).", "336" ], [ "1870 is a 15 year old game that takes 4+ hours to complete (perhaps as much as 8 for the group of new players), it uses fairly unattractive components and can be very unforgiving on a beginner.\nConsidering the above facts - why would anyone, in this day and age of elegant and fast economic games, want to commit (considerable) time and effort to learning and playing this old clunker ? As a lover of Euro games who recently discovered the immense joy that is 18xx system I will try to explain it.\nI will assume no knowledge of 18xx and will approach the review much as I approached game itself some two months back - as a blank slate.\nPhysical Appeal:\nThe components of 1870 are a throwback to a different era in gaming. Everything is cardboard ranging in thickness from a very sturdy board to flimsy rail tiles. Those, some monopoly-like money and business-card like share certificates are the bulk of the physical components of the game. Map is clear and very solid but by no means decorative and certificates can at best be called spartan. All components, however, are very functional. With exception of some shuffling through tiles to find a right one game play will at no point be slowed due to components. Everything, from the size to rather stark color coding is devoted to making the game pieces facilitate game play and to this purpose they perform admirably.\nLearning/Teaching the rules and game setup:\nThis is a bear. Rule book that comes with the game is OK but not great. It certainly beats the AH rulebooks of yore but could definitively stand to gain from more examples and clearer presentation. Even allowing for the mediocre rule book this is not an easiest game to teach. Large part of what drives the game comes from the phase succession which is itself triggered by purchase of trains by various companies. This entire mechanism is fairly unintuitive (at least until one has seen it work) and that means that until one has played a game for a bit one has only a dimmest idea as to the game's main engine. This hit us particularly hard because we approached game as 5 18xx virgins and had our entire first attempt (3+ hours of playing) canned because no one has understood the phase rules. Having a newbie learn from an experienced group would ameliorate this but is all but guaranteed that the newbie will be at significant disadvantage in their first game.", "336" ], [ "Same applies to a lesser extent to the subtleties of the stock market. While basic mechanics there are easy to grasp the small things such as the fact that company receives the payout due to the stocks in the Public Offering (but not in the Open Market) and that one can buy and sell on the same turn are easy to miss and influence the game play fairly significantly. It took us 3 full games and one abortive attempt (starting from absolute zero) before I am fairly confident that we have all the rules straight.\nSetup on the other hand is very simple and components intuitively help with it. Fair bit of table space is required but nothing out of the ordinary.\nGameplay:\nA game turn consists of a stock round and one or more operating rounds.\nIn stock round player (most usually) acts in their own name buying and selling shares in 10 different rail companies. There are certain limitations to stock ownership (total number of certificates owned is limited as is a maximum share one can hold in a given company) which are subject to change due to circumstances of the stock market. This trading will be one way to influence the stock price and will - crucially - determine the ownership and control over the companies themselves. Contrary to most stock-ownership games (Imperial and Acquire come to mind) the stock manipulation in 1870 feels very natural. With exception of the above mentioned restrictions players are given freedom of the market and the price responses of the shares while very simple algorithmically are expectable and logical.\nIn operating round(s) (of which there are between 1 and 3 per turn depending on the phase of the game) players act on behalf of the companies they control. They lay track, purchase trains and conduct runs which bring in revenue. All of the above are very simple natural operations. As a great fan of Age of Steam I expected that a great deal of strategy will be going into making most optimal tracks for the company I controlled. While there certainly is strategy involved in constructing one's rail network this part of the game feels much more forgiving then AoS (though this is not necessarily the case in other 18xx games). Money-making runs are also much simpler affairs then in AoS or even crayon rail games. There is no supply/demand simulation, one simply counts out the number and kind of cities on a run and collects the appropriate amount of money. Only complication to this is a certain bonus company gains if it manages to connect its starting point to a pre-set destination with a single train run.", "629" ] ]

[ 8207, 3235, 3931, 6125, 5285, 8354, 9369, 10801, 10310, 4501, 5569, 3227, 8586, 4480, 10918, 2569, 2560, 10429, 1173, 10946, 3605, 3001, 4851, 10880, 564, 10154, 1639, 10980, 1835, 3936, 7425, 6585, 8462, 5006, 4664, 8193, 8952, 3723, 7133, 778, 2463, 11176, 4838, 8093, 2857, 4830, 11135, 10113, 9901, 3075, 11091, 3289, 4051, 3674, 1812, 11222, 57, 3678, 8145, 10843, 6254, 2320, 9615, 3582, 8331, 8739, 7437, 9988, 2457, 1105 ]

[ [ "Measuring the Boiling Point of Liquefied Gases Using Arduino and PhyPhox\nIntroduction: Measuring the Boiling Point of Liquefied Gases Using Arduino and PhyPhox\nA substance that is in a liquid state is constantly evaporating or passing into the gaseous state (depending on the intermolecular forces and temperature). The pressure exerted by the gaseous molecules produced in this process is known as vapor pressure.\nThe vapor pressure depends on the temperature in such a way that at higher temperature higher vapor pressure. The temperature at which the vapour pressure equals atmospheric pressure is known as the boiling point.\nIn the case of liquefied gases contained in pressure vessels, such as gases used to clean dust, liquefied petroleum gas (LPG) or refrigerant gases, the pressure at which they are kept in the vessel allows a fraction of the gas to be in a liquid state.\nIf this liquid is removed from the vessel and subjected to atmospheric pressure it will begin to evaporate so it will take energy from the surrounding environment lowering the temperature around it. Under these conditions the vapour pressure of the liquid equals the atmospheric pressure and the liquid therefore reaches its boiling point.\nThe aim of this Instructable is to measure that boiling point, which as these are liquefied gases will normally be below 0°C, using an Arduino microprocessor and a waterproof DS18B20 temperature sensor capable of measuring temperatures up to -55°C.\nThe data will be transmitted via Bluetooth to a cell phone provided with the PhyPhox app that will not only allow us to graph and analyze the data but also have access to the sensors of the cell phone, in this case the barometric pressure meter, which will allow us to program the app to correct the boiling point value measured to its standard value referring to atmospheric pressure at sea level or 1 atmosphere.\nThe measured boiling point, in conjunction with other physical tests, e.g.", "152" ], [ "sound speed, can be used for preliminary identification of gaseous substances.\nSupplies\n* Cell Phone (Android or iOS) with barometric pressure sensor (see examples in PhyPhox Sensor DataBase).\n* PhyPhox app (Google Play or AppStore).\n* 1 40 ml Plastic dropper pump (Good Cook brand).\n* 1 Plastic container.\n* 1 Waterproof DS18B20 temperature sensor.\n* 2 Breadbord mini modular.\n* 1 Arduino Nano V3.0 CH340 with mini usb cable.\n* 1 Bluetooth Low Energy BLE CC2541 Bluetooth 4.0 UART.\n* 1 1k ohm resistance.\n* 1 2k ohm resistance.\n* 1 4,7k ohm resistance.\n* Male/Male jumpers wire.\n* Male/Female jumpers wire.\n* 1 Portable battery charger (6000 mAh 3.7V, Out 5V, Output Max. 2.4A).\n* Cutter knife.\n* Silicone glue.\n* Plastic fasteners.\nStep 1: Measuring Probe\nThe measuring probe is basically a conical vessel that is inserted at its narrow end by the DS18B20 temperature sensor leaving enough volume of the cone to completely cover the sensor approximately 5 cm above the end of this one.\nAs a conical container, a plastic dropper pump (40 ml) was used that was cut into two parts, being the narrowest conical end to which the temperature sensor were adjusted and the wider conical end, next to the pump, used as a base.\nThe assembly fits a plastic container that serves as a support and box to hold the Arduino circuit.\nThe following is the procedure for constructing the measuring probe (see images):\nNote: Before mounting the DS18B20 temperature sensor perform the calibration indicated in Step 2.\n* Cut the plastic dropper pump to the height of the 15 ml mark (Caution: cutting hazard).\n* Insert the DS18B20 temperature sensor into the narrowest conical end so that the entire metal body is inside the cone. If necessary increase the diameter of the dropper tip to adjust the sensor.\n* Fix the sensor using silicone rubber or some other low temperature resistant glue. Let dry.\n* Drill a hole in the wider conical base with a diameter that allows the DS18B20 temperature sensor cable to be inserted.\n* Insert into the wide conical base invertedly the conical piece with the sensor inserted passing the cable through the hole previously drilled.\n* Drill a hole in the lid of the plastic container that will serve as a container of the Arduino circuit of such a diameter as to allow the dropper to be inserted by its wider base.\n* Attach the rubber pump to the base of the dropper, under the lid of the plastic container, so that it is fixed to it.", "152" ], [ "Differential Thermal Analysis Using Arduino and PhyPhox\nIntroduction: Differential Thermal Analysis Using Arduino and PhyPhox\nWhen a solid substance is heated the increase in energy manifests itself in the form of an increase in temperature.\nIf the heating rate is constant the temperature increase is also constant as long as there is no change in the structure of the substance.\nAt the time when some kind of transition is initiated in the substance, for example fusion, change of crystal structure or other, the temperature will not increase at the same rate because part of the heating energy will be used in that change of state.\nIf we compare the temperature of the substance that is experiencing the change of state (Sample) with that experienced by another substance that remains stable (Reference) during heating under identical conditions and subtract a temperature value from another (Sample - Reference) we will be performing what is known as Differential Thermal Analysis (DTA).\nThe objective of this Instructable is to show the basics of the DTA using Arduino microprocessor, a home heater and a free access program (PhyPhox) that will allow us to obtain on our cell phones curves of Sample Temperature vs Difference (Sample Temperature - Reference temperature) known as thermograms.\nSupplies\n* Cell Phone (Android or iOS).\n* PhyPhox app (Google Play or AppStore).\n* 1 Plastic container with multiple compartments.\n* 2 Waterproof DS18B20 temperature sensor.\n* 2 Breadbord mini modular.\n* 1 Arduino Nano V3.0 CH340 with mini usb cable.\n* 1 Bluetooth Low Energy BLE CC2541 Bluetooth 4.0 UART.\n* 1 1k ohm resistance.\n* 1 2k ohm resistance.\n* 1 4,7k ohm resistance.\n* Male/Male jumpers wire.\n* Male/Female jumpers wire.\n* 1 Portable battery charger (6000 mAh 3.7V, Out 5V, Output Max. 2.4A).\n* 4 Glass test tubes (approximately 1 cm in diameter and 7.5 cm long)\n* Wooden base (circular or square of approximately 20 cm in diameter or side).\n* 1 Ceiling lampholder (E27).\n* 1 Incandescent light bulb of 25 Watts (E27).\n* 1 Rotary dimmer switch.\n* Approximately 1 m of electrical cable (two cores 0.4 mm thick).\n* 1 Two pin electric socket.\n* 1 Clothes dryer aluminum duct reducer (10.16 cm to 7.62 cm).\n* 2 Disposable circular aluminum plates of approximately 20 cm in diameter.\n* 2 Wire insulate screw cap.\n* Electrical tape.\n* Silicone or Epoxi glue.\n* Plastic fasteners.\nStep 1: Heating Device\nA DTA equipment basically consists of a furnace containing two containers, one for the Sample and one for the Reference and two sensors that measure the temperature of Sample and Reference simultaneously.\nThe temperature inside the furnace and its heating or cooling rate must be very well regulated so the construction of the furnace in professional equipment is an important factor in the design of a DTA apparatus, however for the illustrative purposes of this Instructable it was chosen to make a rather modest design using homemade materials (see supplies list) as indicated below :\n* Fix on a wooden base a ceiling lampholder (E27) provided with two core electrical cable with two pin electric socket.\n* Section one of the cores of the electrical cable and connect a rotatory dimmer switch, using wire insulate screw cap or electrical tape to reestablish the cable connection.\n* Screw an incandescent light bulb (25 Watts, E27) into the ceiling lampholder.\n* With the help of glue, fix on the surface of the ceiling lampholder a clothes dryer aluminum duct reducer (10.16 cm to 7.62 cm) so that the end of smaller diameter is like a chimney around the incandescent light bulb (Caution: Once the bulb is turned on this surface will be hot so there will be a danger of burn).\n* Fold the surface of a disposable circular aluminum plates in such a way as to form a concavity that fits on the chimney formed by the clothes dryer aluminum duct reducer (see video in Step 3).\n* Using another plate repeat the previous operation forming a concavity that fits on the first and in which two holes near the top of the concavity but separated from each other will be drilled, with a diameter that allows to receive the test tubes (approximately 1 cm in diameter and 7.5 cm long) of Sample and Reference.\n* Insert the Sample and Reference test tubes into the drilled holes by pushing until only about 1 cm is left outside. Deform the surface of the aluminum sheet in such a way that they fit on the surface of the test tubes and fix them.", "152" ], [ "Measuring Refrigerant Gases Sound Speed Using Arduino and App Inventor 2\nIntroduction: Measuring Refrigerant Gases Sound Speed Using Arduino and App Inventor 2\nThe purpose of this Instructable is to build a portable device that can measure the speed of sound in refrigerant gases and use this data to identify them.\nThe speed of sound in an ideal gas is related to two characteristics of the gaseous substance, its molecular mass (kg/mol) and its adiabatic constant (heat capacity ratio), or its average values in case of being a mixture of gases.\nIt is for this reason that the measurement of the speed of sound can be used as a preliminary way to identify a pure gas or mixture of gaseous substances.\nThe measurement can be performed using an ultrasonic proximity sensor, to measure the round trip time ( t/2 ) of a sonic pulse in a plastic tube of known length ( x ) (echo method), filled with the gas under study ( v = 2x/t ).\nSince the speed of sound is also absolute temperature dependent, it must be measured using a digital temperature sensor.\nThe values measured by the sensors are captured and processed by an Arduino microcontroller that transmits them via bluetooth to a mobile application, designed with App Inventor 2, which will allow to calibrate the length of the plastic tube using a reference gas whose sound speed is known.\nThe application will use this information to calculate the sound speed of an unknown sample of a refrigerant gas and perform preliminary identification (see disclaimer **).\nSupplies\n* PVC pipe piece approximately 14 cm long and 4.8 cm in external diameter (1-1/2'').\n* 2 PVC pipe caps approximately 4.8 cm in internal diameter (1-1/2'').\n* 2 Toothpaste tube shoulder pressure caps.\n* 1 Piece of leak repair tape about 15 cm x 25 cm.\n* Epoxy glue.\n* 1 Plastic container.\n* 1 Breadbord.\n* 1 Arduino Nano V3.0 CH340 with mini usb cable.\n* 1 HC-SR04 ultrasonic sensor.\n* 1 TMP36 digital temperature sensor.\n* 1 Bluetooth HC-06.\n* 1 1k ohm resistance.\n* 1 2k ohm resistance,\n* Male/male jumpers cable.\n* Male/Female jumpers cable.\n* 1 Male/female usb cable.\n* 1 Portable battery charger (6000 mAh 3.7V, Out 5V, Output Max. 2.4A)\n* Electric tape.\n* Velcro tape.\nStep 1: Measuring Probe\nThe measuring probe is basically a piece of PVC pipe approximately 14 cm long by 4.8 cm external diameter (1-1/2'') to which three holes are drilled, two for gas inlet and outlet (provided with pressure caps of the type used in toothpaste tubes) and another for inserting a digital thermometer.\nThis pipe will be closed at its ends by two PVC pipe caps approximately 4.8 cm internal diameter (1-1/2''). One of the caps will have two perforations to accommodate the emitter and detector of the ultrasonic sensor. This part of the device is going to be the point of emission and detection of ultrasonic pulses, while the flat face of the other cap, opposite the emission point will be the rebound point (echo) of the pulses.\nThe following is the procedure for constructing the measuring probe:\n* From a 1-1/2'' PVC pipe cut a piece about 14 cm long.\n* About 4 cm from each end of the tube piece make two perforations, in opposite directions, approximately 5 mm in diameter.\n* On the perforations made paste with epoxy resin the two pressure caps of toothpaste tubes.\n* Halfway through the tube and perpendicular to the plane formed by the two holes described above open a hole about 1 cm in diameter.\n* Through the above hole insert the temperature sensor TMP36, attached to its connecting cables and with the help of electrical tape stick to the upper inner wall of the PVC tube leaving exposed the sensor head.", "152" ], [ "Fix externally with epoxy glue.\n* Make two perforations approximately 1.5 cm in diameter separated by 2.5 cm to one of the PVC pipe caps so that they adjust the emitter and receiver of the ultrasonic sensor HC-SR04 and that are centered on the face of the cap. Fix the HC-SR04 sensor with expoxi glue making sure to seal all slots. Let the glue dry.\n* Place the cap with the ultrasonic sensor and the cap that will function as a rebound surface, at the ends of the tube (measurement probe). Coat the rest of the exposed externas surface of the tube with leak repair tape so that it is thermally insulated.", "320" ], [ "Low-Cost Rheometer\nIntroduction: Low-Cost Rheometer\nThe purpose of this instructable is to create a low cost rheometer to experimentally find the viscosity of a fluid. This project was created by a team of Brown University undergrad and graduate students in the class Vibration of Mechanical Systems.\nA rheometer is a lab device used to measure the viscosity of fluids (how thick or sticky a fluid is -- think water vs. honey).", "707" ], [ "There are certain rheometers that can measure the viscosity of fluids by measuring the response of a vibrating system submerged in a fluid. In this low-cost rheometer project, we created a vibrating system from a sphere and spring attached to a speaker to measure the response at different frequencies. From this response curve, you can find the viscosity of the fluid.\nSupplies\nMaterials Needed:\nHousing Assembly:\n* Particle Board (11’’ W x 9’’ H) (here) $1.19\n* 12 x 8-32 x 3/4'' Hex head screws (here) $9.24 tot\n* 12 x 8-32 Hex nut (here) $8.39\n* 4 x 6-32 x ½’’ Hex head screw (here) $9.95\n* 4 x 6-32 Hex nut (here) $5.12\n* 9/64'' Allen Key (here) $5.37\nElectronics:\n* 12V Power Supply (here) $6.99\n* Amplifier (here) $10.99\n* Aux Cable (here) $7.54\n* Jumper Wire (see below)\n* Alligator Clips (here) $5.19\n* Speaker (here) $4.25\n* Screw Driver (here) $5.99\nSpring & Sphere Set Up:\n+ 3D printer resin (variable)\n+ 2 x accelerometers (we used these) $29.90\n+ 10 x female-male rainbow cables (here) $4.67\n+ 12 x male-male rainbow cables (here) $3.95\n+ Arduino Uno (here) $23.00\n+ USB 2.0 Cable Type A to B (here) $3.95\n+ Bread board (here) $2.55\n+ Compression Springs (we used these) ??\n+ 2 x Custom Connectors (3D printed)\n+ 2 x ⅜’’-16 Hex nuts (here) $1.18\n+ 4 x 8-32 Set Screws (here) $6.32\n* 4 x ¼’’-20 Hex nut (Aluminum) (here) $0.64\n* 2 x ¼’’-20’’ Threaded Rod (Aluminum) (here) $11.40\n* 7/64'' Allen Key\n* 5/64'' Allen Key\n* 4 x 5x2mm 3/16’’x1/8’’ Screws (here) $8.69\nOther\n* Plastic Cup (here) $6.99\n* Liquid to test viscosity (we tested karo syrup, vegetable glycerine, Hershey’s chocolate syrup)\nTOTAL COST: $183.45*\n*does not include 3D printer resin or liquid\nTools\n* Laser Cutter\n* 3D printer\nSoftware Needed\n* MATLAB\n* Arduino\nFiles and Code:\n* Adobe Illustrator file for the housing assembly (Rheometer_Housing.ai)\n* Speaker Controller GUI (ENGN1735_2735_Vibrations_Lab_GUI_v2.mlapp)\n* Arduino Rheometer File (rheometer_project.ino)\n* Sphere mesh files (cor_0.9cmbody.stl and cor_1.5cmbody.stl)\n* Custom Connector ASCII geometry file (Connector_File.step)\n* MATLAB Code 1 (ff_two_signal.m)\n* MATLAB Code 2 (accelprocessor_foruser.m)\n* MATLAB Code 3 (rheometer_foruser.m)\nStep 1: Part 1: Set Up\nHow to setup the experimental platform.\nStep 2: ​3D Print and Laser Cut All Parts (custom Connectors, Spheres, and Housing)\nStep 3: Connect the Electronics As Shown Below\nImportant to note: Do not plug the power supply into the outlet until all steps in this section are completed! ALWAYS UNPLUG THE POWER SUPPLY WHEN MAKING ANY CHANGES.\nTo start, make sure the amplifier is placed with the knob facing away.", "611" ], [ "Solid State Optical Sump Pump Controller\nIntroduction: Solid State Optical Sump Pump Controller\nRecently I found out my dad had an inconvenient situation with the sump pump in his basement. The sump pump sits at the bottom of a four foot deep well and is activated by a small float that moves up and down. The float is connected to a mechanical switch on the pump housing.\nDuring the wet season, the pump turns on and off about once a minute and the switch contact lasts only about a year before succumbing to mechanical failure. When it does, my dad has to undo the outlet hose, hoist the pump out of the well and replace it with a spare pump he keeps around for the task. Then, he replaces the switch contactor on the broken pump so he can have it ready for next year. This costs about $40 a year, not to mention the labor involved in swapping out the pumps and replacing the contactor each time.\nTo solve the problem, I set out to design a solid state optical sump pump controller that has no moving parts to wear down. My idea was to bypass the mechanical float on the pump itself and to instead make a new float that would mount to the side of the well. This would consist of a plastic bottle and a dowel rod. The dowel rod would move up and down and trigger two optical sensors mounted on the side of the well. I would then build a circuit to turn the pump on and off using a solid state relay.", "742" ], [ "Because this would be contactless and have no electromechanical parts, it would never fail due to wear.\nSupplies\nFloat Assembly:\n* One plastic bottle\n* One dowel rod\nOptical Float Level Sensor:\n* Two Photointerrupters\n* Hookup wire\nOption 1: TTL Based Control Logic:\n* Two 2.2kΩ resistors\n* One 100Ω resistor\n* One 7400 quad-NAND gate integrated circuit\n* One 180Ω resistor (optional)\n* One indicator LED (optional)\n* One protoboard PCB\nOption 2: Arduino Based Control Logic\n* One 100Ω resistor\n* One Arduino Uno (an ATTiny based board could work as well)\nPower Supply:\n* One 5V USB charger\n* One USB cable\nPump Relay Assembly:\n* One solid state relay\n* One AC plug\n* One AC outlet\nStep 1: Making the Optical Water Level Sensor\nThe water level sensor consists of a shaft with a central hole slightly larger than the dowel rod. When mounted to the side of the well using the attachment bracket, it allows the float and dowel rod to slide freely up and down along with the water level in the well.\nAt two points along this shaft are positioned photointerrupters. These devices consist of a infrared light source and a light detector. When the dowel rod slides into the groove in the photointerrupter, it interrupts the light beam, turning off the current through the light detector. The photointerrupter sit well above the water level and are not intended to get wet.\nI chose to make the water level sensor shaft out of 3D printed segments so that I could easily adjust the length by adding segments as needed. Each segment has a central cutout for inserting a photointerrupter, but only two of the segments will have one.\nI also made a bracket for attaching the sensor to the side of the well.\nAutodesk Fusion 360 Design\nStep 2: Wiring and Operation of the Water Level Sensor\nAlong the sensor bar, there will be photointerrupters that will be blocked by the dowel rod when the water reaches the low and high point. One side of each photointerrupter contains an LED light source. Both of these will be wired from 5V, in series with a current limiting resistor (shown in the schematic), down through a common ground.\nThe side of the photointerrupter with a dot contains a light sensitive transistor. The signal lines go to the leads nearest the dot, while the opposite leads are wired to a common ground.\nThe control logic will pull the two signal lines up to 5V while the phototransistor is in shadow, but if light falls on the transistor, it will conduct and bring the signal line to 0V; therefore, when the dowel rod is present, the signal line will read 5V, while when it is absent, it will read 0V.\nI used an ITR9608-F photointerrupter because it has a 5mm gap, which is just wide enough to let my dowel rod through.\nStep 3: Making a Float With an Adjustable Rod\nFor the float, I used a small plastic bottle and the dowel rod. I wanted the length of the rod to be adjustable, so I drilled a hole on the bottle cap to allow me to insert the rod partially into the bottle.", "267" ], [ "Arduino Based Tachometer for Gym Cycles\nIntroduction: Arduino Based Tachometer for Gym Cycles\nMy grandfather tries to exercise regularly on the gym cycle he has, however, the display for the cycle is broken. Therefore he is unable to see the distance travelled by him after exercising for a certain period of time.\nThe LCD used on the gym cycle to display the data was custom made and could not be replicated. He was unwilling to exercise without an indication of the distance travelled.\nTherefore, I came up with this solution where my grandfather could still measure the number of cycle revolutions over a certain period of time and calculate the distance travelled.\nThis project won't apply for regular cycles, but for exercise bikes, it is a perfect option if the LCD display is old or damaged.\nThe design of the circuit is very similar to one of my previous projects: Distance sensor (for white cane). Please check it out if you would like to. https://www.instructables.com/Distance-Sensor-for-...\nSupplies\n1) 1 x 16x2 LCD screen (link)\n2) 40 x Male to Male and Male to female jumper wires (link). You need an assortment of male to male and male to female wire (link)\n3) 1 x HC-SR04 Ultrasonic sensor (link)\n4) 1 x Arduino Uno or Arduino Nano with its connecting cable (link)\n5) 1 x 170 point-small-breadboard (link)\n6) 1 x Potentiometer or trim pot for controlling the LCD's contrast (link)\nStep 1: How the HC-SR04 Ultrasonic Sensor Works With the Arduino\nThe HC-SR04 ultrasonic sensor works on the principle of sound wave reflection. One side of the sensor sends an ultrasonic wave and the other side of the sensor detects it.\nThese two sides are used in conjunction, the trig pin of the HC-SR04 is activated, which causes the sensor to shoot an ultrasonic sound wave.\nThe echopin then comes into play.", "939" ], [ "The sensor gives out a high value on the echo pin when it detects that the sound wave has reflected and come back.\nThe Arduino and its code are used to measure the time difference between the ultrasonic sensor's trig pin being activated and the echo pin turning high.\nThis time difference is essentially the time taken for sound to traveltwo times the distance (because it is being reflected) between the sensor and the object it is being pointed at.\nKnowing the speed of sound, about 340 m/s, and the time difference makes it very easy to calculate the distance.\n2 * distance = speed of sound x time dif.\nActual distance = 0.5 x 340 x time dif.\nHere is a link that might explain the circuit a little better. https://howtomechatronics.com/tutorials/arduino/ul...\nThe other two pins on the sensor, Vcc and GND, are connected to the +5V supply and ground pins on the Arduino respectively. They are there just to power the sensor.\nStep 2: How the Device Works\nThe entire device sits right underneaththepedal so that when the pedal with the ultrasonic sensorpointingup on to the underside of the pedal.\nThe device is constantlymeasuring the distance between the sensor and the pedal. Since the person is cycling, this value would be changing constantly similar to a sinecurve.\nWhen the pedal is on its lowestpoint the distance measured by the sensor and recorded by the Arduino is less than the set thresholdvalue in the code.\nThis causes a counter value on the Arduino to increase by 1 indicating that one revolution has been completed. This then can be translated to actualdistance using the diameter of the gym cycle wheel.\nThe devicestarts immediately recording the number of revolutions once it's USB cable has been plugged into a power source. This power source can be a laptop, power bank, or an adapter from the wall.\nStep 3: Wiring the LCD\nPins D2, D3, D4, D5, D11, and D12of the Arduino is connected to pins 14, 13, 12, 11, 6, and 4 of the LCD, respectively.\nThe pins will be numbered directly on the Arduino. For the LCD you can count the pins from left to right if they aren't already numbered.\nThese are roughly the data pins which transmit information from the Arduino to the LCD about what to display on the screen.\nPins1, 5, and 16 of the LCD are connected to ground.\nPins2 and 15 of the LCD are connected to +5V.\nPin 3 of the LCD is connected to the middle terminal of the Potentiometer or trim pot. One of the other two terminals of the Potentiometer or trim pot should be connected to ground and the other to +5V.", "939" ], [ "Simple Arduino Pot Plant Soil Moisture Sensor\nIntroduction: Simple Arduino Pot Plant Soil Moisture Sensor\nArduino Pot Plant Soil Moisture Sensor\nI have been struggling with over watering of my indoor pot plants, especially succulents. To this end I decided to make a simple Soil Moisture sensor that can tell me when the moisture level of my pot is too high (over watered), too low or just right!\nSupplies\n* Capacitive Soil Moisture Sensor V1.2\n* WS2182b mini\n* 3D Printing Filament\n* Arduino\nStep 1: Step 1: Gather Your Components\nI have used an Arduino Leonardo (this is what I had on hand and this project would work with any type of Arduino).\nI soldered wires directly to the Arduino headers. Using the Schematic attached.\nThe Moisture Sensor will work correctly on any Analogue in pin and the WS2812B mini should work on many digital pins however in my case I used D2.\nStep 2: Step 2: Calibrate Sensor\nThe Principle behind the sensor used is that as the moisture content increases so too does the capacitance in the sensors circuit placed in the soil. To use the Capacitive Soil Moisture Sensor V1.2 we supply either a 5V or 3.3V power source (ideally a stable voltage source) we can then read an analogue voltage from the sensor that corresponds to the capacitance of the sensor and therefor the moisture level of our soil.\nGiven there can be variances between manufactures and even parts it is sensible to calibrate the sensor so it works for the specific sensor we have. This may not be 100% necessary however can improve the performance of your sensor.\nCalibrating the Sensor:\n1. Connect Sensor to computer running Arduino Script\n2. Open Serial Monitor (Arduino will output raw values from the ADC on the Arduino. Value between 0 and 1023)\n3. Note the value seen when the sensor is in the air\n4.", "152" ], [ "Submerge the sensor into water up to the point you would in your pot. Note the value seen while in the water.\nNow that you have noted the \"dry\" and \"wet\" value it is time to update the Arduino script with this information.\nGo to Moisture Sensor Setup in Line 19 and update AirValue and Water Value with those you have recorded.\n//Moisture Sensor Setup\nconst int AirValue = 900;\nconst int WaterValue = 680;\nStep 3: Step 3: Select Limits\nEvery plant is different! Some plants like a dry soil and prefer to be watered once and then left for a while. Others need moist soil almost contently and will need watered regularly. At this point we need to decide what we want to consider as over watered and under watered! This differs plant to plant.\nNote: The Arduino Script has some small logic to convert the reading into a percentage where 0% Moisture would be the value you recorded in Air and 100% Moisture being the value you recorded when submerged in water.\nGiven we are now working with percentages we need to pick a percentage Moisture we want to be alerted at when we need to water and one to know when the plant is over watered. Anything in between and the plant will be happy!\nThe table bellow shows the values I have found good for different plants. Comment what values have worked for your plants!!\nPlant Over Watered Percentage Under Watered Percentage Strawberry 90% 35% Butterfly Palm 85% 30% Aloe 70% 15%\nStep 4: Step 4: Print the Case and Assemble\nI 3D printed the case for the sensor to hold it in a small and simple box. I wanted something slim so decided to only use the moisture sensor however with some further work and the inclusion of a simple Light Dependent Resistor this design could be extended to make sure your plants are getting the correct amount of light.\nThe 3D files for the case can be downloaded from Github.\nOnce printed it is time to assemble! You should have the Arduino, sensor and LED soldered together. Now place the LED into the recess hole and the moisture sensor in its location. Place the cover on top and glue in place (I used Blu-Tack).\nStep 5: Step 5: Be the Perfect Plant Parent\nThe LED have three colours to show you the Moisture in your pot!\nSee the table bellow to know what the sensor is saying.\nBlue Over Watered Green Happy Plant Red Needs Water", "33" ], [ "Water Rocket - Electronic Systems Design\nIntroduction: Water Rocket - Electronic Systems Design\nIn this instructable, we are gonna build a Water Rocket with an automatic parachute ejection mechanism, and a data transmission system so we can monitor the rocket's orientation (estimated from accelerometer and gyroscope data) while it's on the air.\nA water rocket is a model rocket that uses water and compressed air inside a pressure chamber (usually a PET bottle) as a thrust motor. The operation of the rocket can be explained by <PERSON>'s third law, where the water in the compression chamber is thrown out by the compressed air as it tries to release its pressure releasing the accumulated potential energy, causing a force to be generated in the opposite direction that propels the rocket.\nSupplies\nRocket airframe\n* 3x PET Bottles 3L size (*It’s important that at least one of the bottles was used to store soda because it has to be able to withstand high pressures)\n* 4x Balsa wooden boards 200*25mm\n* 8x Screw\n* 1x Spray paint\n* 1x Rubber band\n* 1x Parachute (We used an old umbrella, attaching rope to each tip of the cloth)\n* 1x Corrugated plastic board 250*250mm (Also known as Correx or Corriflute)\nElectronics\n* 4x Zip Ties\n* Cardboard\n* 1x Perfboard (Also known as solder-able breadboard)\n* 1x Accelerometer (We used an MPU6050, it has an accelerometer and gyroscope)\n* 2x Arduino board (We used an Arduino nano and an Arduino mega)\n* 1x 3.3 V Voltage regulator (We used the LM317 adjustable voltage regulator)\n+ For the Voltage regulator circuit using an LM317\no 1x Resistor (390 Ohm)\no 1x Resistor (240 Ohm)\n* 1x Servomotor (We used a generic SG90)\n* 2x NRF24L01+ module\n* 1x Battery to supply power to the electronics board (We used a Power Bank)\n* To connect the Power Bank to the electronics board.\n+ 1x USB male type A connector\n* Female & Male headers\n* Tape\n* Double-sided tape\n* Cables & Wires\n* Hot glue\nTools\n* Hot glue gun\n* Cutter\n* Scissors\n* Marker\n* Soldering iron\n* Tweezers\n* Measuring tape\n* Stapler\n* Water Rocket Launcher (We don't explain in this instructable how to make the rocket launcher, but you can check out this amazing article by air command water rockets to build one yourself)\nStep 1: Parachute\nMeasure the radius of the bottle\nFor this measure the circumference as seen in (1), then apply the equation r = c / (2*pi) (where c is the circumference) to find the radius, in our case the radius was 60 mm\nWith this information mark 2 circles with the radius of the bottle minus 1 mm (in or case that was 59 mm) on a cardboard and cut them, as shown in (2) and (3).\nFor each circle, make the lines as shown in (4)\nFor this, we first make a line that goes through the center of the circle, this line will be called line 1\nMeasure 40 mm on one end of line 1 and draw a perpendicular line that touches the borders of the circle, this line will be called line 2\nMeasure 20 mm on the other end of line 1 and draw a point\nNow draw a line between the point and each end of line 2\nMeasure one of the recently drawn lines, this value will be called L\nStep 2:\nTaking the above measurement (L), draw on the cardboard a rectangle 110 mm high, and (L) x 4 mm wide, mark a vertical line every (L) mm (5)\nCut the large rectangle and cut the line at the middle resulting in 2 rectangles of equal size as shown in (6)\nFor each of the rectangles, cut the top layer of the cardboard through the marked line so we can fold them\nPut hot glue on the lines marked on one of the circles and glue one of the folded rectangles, then glue the other rectangle behind the previous one to reinforce it.\nWe need holes for the zip tipes, so mark a line approximately 15 mm from each end of the rectangle, and draw 4 rectangles attached to that line approximately 3 mm high by 5 mm wide that are approximately equal distances apart as shown in (9)\nGlue the other circle on top\nCut the small rectangles and verify that the zip ties fit through the recently made holes.", "120" ] ]

[ 11276, 3367, 5929, 7797, 8768, 10775, 10385, 8142, 3458, 9953, 3208, 7844, 9452, 6614, 11157, 10711, 10881, 6660, 1765, 2709, 6109, 6089, 6609, 5814, 9118, 2515, 3680, 6463, 6328, 4463, 8787, 10381, 196, 2202, 7678, 731, 8571, 3835, 8767, 2137, 7687, 2383, 11299, 11138, 4816, 11001, 10075, 1884, 2252, 1395, 9291, 173, 6745, 2716, 6988, 4377, 5757, 2223, 10693, 3263, 6065, 10618, 7585, 5005, 2624, 8618, 6761, 3671, 2405, 3369 ]

[ [ "General notes on LTL\nIntuitively, LTL formulas are statements about infinite sequences (or \"infinite words\"). First, you have to understand what these sequences consist of.\nIn the usual definition of LTL, you start with a set of atomic propositions $AP$. For example $AP = {a,b}$. These atomic propositions then act as the base elements of your LTL formulas, so you could have an LTL formula $\\varphi = a$ or $\\psi = a \\land \\lnot b$ and so on. Then you can add the temporal operators, so you could also have LTL formulas like $\\varphi' = \\Box a$ or $\\psi' = a \\land \\Diamond \\lnot b$ and so on.\nFor the semantics of LTL, we then consider infinite words over the power set of $AP$. So for $AP = {a,b}$ we are looking at infinite words where each symbol is one of $\\emptyset$, ${a}$, ${b}$ or ${a,b}$. For example we could have a word $\\sigma = {a,b}{a}{a}{a}...$, where the first symbol is ${a,b}$, and all following symbols are ${a}$.\nYou would then define the meaning of an LTL formula $\\varphi = a$ to be such that a word $\\sigma$ satisfies $\\varphi$ iff $a \\in \\sigma(0)$. Put differently, an LTL formula $\\varphi$ consisting of a single atomic proposition is satisfied by a word $\\sigma$ iff the set of atomic propositions that is the first symbol of $\\sigma$ contains $\\varphi$. We denote this by $\\sigma \\models \\varphi$. So for $\\sigma = {a,b}{a}{a}{a}...$, you have $\\sigma \\models a$, because $a \\in {a,b}$.\nYou would then expand the definition to the other operators, so for example you would say the meaning of $\\varphi = \\Box \\psi$ is such that a word $\\sigma$ satisfies $\\varphi$ iff every infinite suffix of $\\sigma$ (in your notation for every $k \\in \\mathbb N$ the word $(\\sigma,k) = \\sigma(k) \\sigma(k+1) \\sigma(k+2)...$ ) satisfies $\\psi$.", "9" ], [ "So using the same $\\sigma$ as before, we would have $\\sigma \\not \\models \\Box b$, as the suffix $\\sigma(1)\\sigma(2)\\sigma(3)... = {a}{a}{a}...$ does not satisfy $b$, since $b \\notin {a}$.\nUsing a more practical example: Suppose you want to model a robot that has an arm with a grabber for picking things up from the ground. You could have $AP = {\\text{arm_down}, \\text{grabber_closed}}$. Then a word $\\sigma$ represents a specific behaviour of the robot (assuming it runs infinitely). So for example $\\sigma = \\emptyset {\\text{arm_down}}{\\text{arm_down,grabber_closed}}{\\text{grabber_closed}}{\\text{grabber_closed}}...$ represents the robot behavior of the robot picking something up from the ground and then holding it indefinitely:\n1. Arm is up and grabber open.\n2. Arm is now down.\n3. Arm is down and grabber has closed.\n4. Arm is up and grabber closed.\n5. ...\nAn LTL formula would then make a statement about the behavior of a robot. For example $\\varphi = \\Box \\Diamond \\lnot\\text{arm_down}$ would mean \"it is always true that eventually the robot arm is not down\" or in other words \"if the arm moves down it has to move up again at some point\".\nRegarding your question\nAs I understand your question, you are asking \"are there $\\varphi$ and $\\psi$, such that there is a $\\sigma$ which satisfies $\\Box (\\varphi \\lor \\psi) \\Rightarrow (\\Box \\varphi) \\lor (\\Box \\psi)$?\".\nThe answer to that would be yes, you could for example take $AP = {a,b}$ and $\\varphi = a$, $\\psi = b$.\nThen the word $\\sigma = \\emptyset \\emptyset \\emptyset ...", "9" ], [ "If $F$ is valid then $F \\cup res(C_1,C_2,A_i)$ is valid\nI have to prove the following problem in propositional logic:\nLet $F$ be a set of clauses and let $F' = F \\cup {res(C_1,C_2,A_i)}$ be the extension of $F$ by a resolvent of some clauses $C_1,C_2 \\in F$ where $A_i$ is a literal occuring positively in $C_1$ and negatively in $C_2$.\nProve that: If $F$ is valid, then $F'$ is valid.\nSo in other words I have to prove that when I construct the union of the original formula $F$ and the formula resulting by applying resolution on $F$ over a literal $A_i$ in $F$, validity is still preserved.\nI think that this should be provable by applying a direct proof.\nRecall: Note that resolution is defined as follows: given two clauses: $C_1 = (A_1 \\lor \\dots \\lor A_i \\lor \\dots \\lor A_n)$ and $C_2 = (B_1 \\lor \\dots \\lor B_j \\lor \\dots \\lor B_m)$ such that for some $i, j$ with $1 \\leq i \\leq n$, and $1 \\leq j \\leq m,\\; A_i = \\neg B_j$,\nthe resolvent of $C_1$ and $C_2$ on $A_i$ is the clause\n$res(C_1,C_2,A_i) = (A_1 \\lor \\dots \\lor A_{i-1} \\lor A_{i+1} \\lor \\dots \\lor A_n \\lor B_1 \\lor \\dots B_{j-1} \\lor B_{j+1} \\lor \\dots \\lor B_m)$\nEDIT: Here is my try:\nLet $I$ be an interpratation taken from the set of models $Mod(F)$. Hence, $I(F) = 1$. Because this interpretation satisfies $F$ it must also be the case that it satisfies $C_1$ and $C_2$.", "945" ], [ "If we take a look at the structure of $C_1$ and $C_2$ we have to distinguish between $2$ different cases:\n(1) $A_i$ is positive in $C_1$ but negative in $C_2$ and\n(2) $A_i$ is negative in $C_1$ but positive in $C_2$.\nIn case (1) if $A_i$ is set to true in $C_1$ it would be false in $C_2$. In case (2) if $A_i$ is set to true in $C_2$ it would be false in $C_1$.\n$A_i$ cannot be the literal which preserves satisfiability of $F$. Hence $I$ must include some assignment of other literals in $F$ such that $F$ is satisfied. Thus, the resolvant $res(C_1,C_2,A_i)$ is also satisfied.", "610" ], [ "We typically think of instances to problems as being in some format. There are several ways to think of this. Consider for example $A_{TM}$, in which the input is a pair $\\langle M,w \\rangle$. The three most obvious are:\n1. Every input string can be decoded into an input pair $\\langle M,w \\rangle$.\n2. Inputs not of the form $\\langle M,w \\rangle$ don't belong to the language.\n3. We think of $A_{TM}$ as a promise problem: inputs $\\langle M,w \\rangle$ where $M$ accepts $w$ are Yes instances, inputs $\\langle M,w \\rangle$ where $M$ doesn't accept $w$ are No instances, and we don't care about other inputs.\nIf you take complementation, here is what you get under each interpretation:\n1. $\\overline{A_{TM}}$ consists of all inputs strings which, when decoded to $\\langle M,w \\rangle$, are such that $M$ doesn't accept $w$.\n2.", "399" ], [ "$\\overline{A_{TM}}$ consists of inputs not of the form $\\langle M,w \\rangle$, and of those of the form $\\langle M,w \\rangle$ such that $M$ doesn't accept $w$.\n3. $\\overline{A_{TM}}$ is the promise problem corresponding to option 1.\nWhile these different interpretations look different, in practice the difference is very slight, given that it is easy to recognize that the input is of the correct format. For example, given interpretation 2, consider the following two languages: $\\overline{A_{TM}}$, and $\\widetilde{A_{TM}}$, the language of all pairs $\\langle M,w \\rangle$ such that $M$ doesn't accept $w$. These two languages differ in malformed inputs, that is, outputs not of the form $\\langle M,w \\rangle$. Since such inputs are easy to detect, we have an algorithm for $\\overline{A_{TM}}$ iff we have one for $\\widetilde{A_{TM}}$, and furthermore, the complexity of both algorithms is very similar.\nFor this reason, we typically ignore such issues, and implicitly work under the \"promise problem\" interpretation: the input is assumed to be of the form $\\langle M,w \\rangle$. Purists can think of the first interpretation instead, which from this point of view behaves identically.\nMore generally, whatever interpretation you choose, you still formally have to describe what encoding is used for $\\langle M,w \\rangle$. We typically don't bother, since all reasonable interpretations are inter-reducible, and so don't change the computability or complexity of the problem. That said, the difference between weak NP-hardness and strong NP-hardness lies exactly in which input representation is being used.", "399" ], [ "Could a modification of <PERSON>'s proof system be used to solve 3-SAT in polynomial time?\nA literal is a nonzero integer, and we define $\\sim x = -x$.\nA clause is a nonempty set of literals.\nA CNF is a set of clauses.\nA K-rule is a pair $(F,C)$ where $F$ is a CNF and $C$ is a clause.\nA <PERSON>-style proof system (KPS) is a set of K-rules.\nIf $S$ is a KPS, then an $S$-proof of $C$ from $F$, or an $(S,F)$-proof of $C$, is a sequence $\\langle C_1,..,C_n\\rangle$ of clauses such that $C = C_n$ and for all $1\\le i\\le n$, either $C_i \\in F$ or there is a K-rule $R = (G,A) \\in S$ and a function $f : {x,\\sim x : x \\in B \\in G \\lor x \\in A} \\rightarrow \\mathbb{Z}_{\\ne 0}$ which respects negation such that letting $g(B) := {f(a) : a ∈ B}$, we have $C_i = g(A)$, and for all $B \\in G$, there exists some $j < i$ with $C_j = g(B)$.\nFor fixed $S$, the language ${(F,C) : F \\vdash_S C}$ is polynomial-time decidable:\nread inputs F and C\nif C ∈ F\nreturn true\nlet D = {x1,~x1,..,xn,~xn} be the set of literals occuring in F or C, and their negations\nContin := true\nwhile Contin\nContin ← false\nfor (G,A) in S\nfor h : {abs(x) : x ∈ B ∈ G ∨ x ∈ A} -> D # there are |D|^c such functions\nf(x) := (x > 0 ? h(x) : -h(-x))\ng(B) := {f(a) : a ∈ B}\nfor B in G\nif g(B) ∉ G\ncontinue in the for-loop where h is chosen\nif g(A) ∉ F\npush g(A) to F\nContin ← true\nif C ∈ F\nreturn true\nelse\nreturn false\n$S$ is sound if for all CNF's $F$ and clauses $C$, the existence of an $(S,F)$-proof of $C$ implies that $F \\vDash C$.\n$S$ is complete for a class $\\Gamma$ of CNF's if for all $F \\in \\Gamma$ and $C$, if $F \\vDash C$ then $C$ is $(S,F)$-provable.\nNo KPS is complete for full $SAT$, since any clause of the form ${-1,1,2,3,..,n}$ is tautological, but for any system $S$, $sup{|A| : (\\emptyset,A) \\in S}$ is only finite, making the clause $(S,\\emptyset)$-unprovable for sufficiently large $n$.\n${({{1},{-1}},{2})}$ is complete for $1$-$SAT$, and represents the rule $a,\\sim a \\vdash b$.\n${(\\emptyset,{1,-1}),({{1}},{1,2}),({{1,2},{-1,3}},{2,3})}$ is complete for $2$-$SAT$, and represents the system consisting of the rules (1) $\\vdash a\\lor\\sim a$, (2) $a\\lor a \\vdash a\\lor b$, and (3) $a\\lor b, \\sim a\\lor c \\vdash b\\lor c$.\nQuestion 1. Is it known that no sound KPS can be complete for $3$-$SAT$?\nIf such a KPS was found, it would imply $P=NP$ and the polynomial-boundedness of natural propositional proof systems.", "330" ], [ "Give a finite set of identities $E$ such that the ground word problem is decidable, but the word problem is not\nI am studying term rewriting using <PERSON> and <PERSON>'s book \"Term Rewriting and All That\". I am trying to solve the following exercise about word problems:\n4.1 Give a trivial example of a finite set of identities $E$ such that the ground word problem for $E$ is decidable, but the word problem is not.\nMy idea to solve this relies on an example the authors give in this section, shown below with minor modifications:\nExample 4.1.4\n$${(xy)z \\approx x(yz), \\ aba^2b^2 \\approx b^2a^2ba, \\ a^2bab^2a \\approx b^2a^3ba, \\ aba^3b^2 \\approx ab^2aba^2, \\ b^3a^2b^2a^2ba \\approx b^3a^2b^2a^4, \\ a^4b^2a^2ba \\approx b^2a^4 }$$\nThe equations above show a finitely presented semigroup with undecidable ground word problem due to <PERSON> [170]. In the terminology of this book, we have one binary infix function $\\cdot$ and two constants $a$ and $b$, together with the identities shown above.", "474" ], [ "For readability $x \\cdot y$ and $x \\cdot \\cdot \\cdot x$ are written $xy$ and $x^n$. Associativity allows us to drop brackets.\nAfter that the authors note that:\nWe can recast this example in terms of unary function symbols only, drop \"$\\cdot$\" and the associativity rule, turn $a$ and $b$ into unary functions, and interpret an identity like $ab \\approx ba$ as $a(b(x)) \\approx b(a(x))$. Because there are no ground terms, this only yields the undecidability of the word problem.\nSo, as far as I understood the transformation described in the comment above by the authors already solves the exercise. The ground word problem would be decidable vacuously since there are no ground terms and the word problem obtained by doing the mentioned transformation is undecidable since it is equivalent to the ground word problem proved undecidable by <PERSON>.\nIs this reasoning correct and is that all I need to do for this question? Or is there a simpler example that I missed?\nThank you in advance.", "617" ], [ "I'm using r.e. to mean \"recursively enumerable\" and co-r.e. to mean \"the complement is recursively enumerable\". I'm assuming by $L'$, you mean the complement of $L$.\nTo answer your questions directly:\n1. This is not correct. Every language over a finite alphabet $\\Sigma$ has a one-to-one correspondence to the natural numbers. To show this, you would have to construct a one-to-one function that maps the words of your language to natural numbers. This isn't difficult at all, but a bit technical, so I'm only going to sketch the construction: Pick some well-founded total order $\\leq$ on $\\Sigma^*$, for example the lexicographic order. For $w \\in L$, define $$predecessors(w) := { v \\in L \\mid v \\lneq w}$$ to be the set of words in $L$ preceding $w$ according to your order. Define a mapping $f: L \\to \\mathbb N$, by $f(w) := |precedessors(w)|$, assigning to each word the number of its predecessors. You could then show that $f$ is in fact a one-to-one mapping. This construction works for any language, though it is not necessarily computable for all languages.\n2. Correct, when $L$ is not co-r.e., by definition $L'$ is not r.e., so there cannot be an algorithm that enumerates $L'$.\n3. Correct, your theorem says $L$ is r.e., therefore $L'$ is co-r.e. Note this follows from the first premise of your theorem, not from the latter premise. In general, $L'$ being not r.e. on its own does not imply $L'$ being co-r.e. In other words, there are languages that are neither r.e.", "945" ], [ "nor co-r.e., see here.\nTo elaborate a bit more on what the theorem means: It says there is a language $L$ that is r.e. but not co-r.e.\nThe important insight is that if a language $L$ is r.e. and co-r.e., then it is decidable. Assume you have a TM $M$ for enumerating $L$ and a TM $M'$ for enumerating its complement $L'$. Then you can build a new TM $M^\\star$ for deciding $L$: For a given input $w$, $M^\\star$ simulates $M$ and $M'$ in parallel. Since either $w \\in L$ or $w \\notin L$, one of $M$ or $M'$ has to enumerate $w$ eventually. At this point, $M^\\star$ stops the simulation and accepts or rejects $w$ based on which of $M$ and $M'$ enumerated it. It follows that $M^\\star$ halts on all inputs and accepts $w$ iff $w \\in L$. Therefore, $L$ is decidable.\nBased on this insight, if you can find a language $L$ that is r.e. and undecidable, you can then conclude that it cannot be co-r.e. Since if it would be co-r.e. it could not be undecidable.\nThe usual example would be some variant of the halting problem, e.g. $H = { \\langle M,w\\rangle \\mid M$ is a Turing Machine that halts on input $w}$. You should know that $H$ is undecidable. To show that $H$ is r.e., you would have to construct a TM that enumerates $H$. I'm only going to sketch the proof: Your TM $M^$ would iterate over triples of the form $\\langle M, w, n \\rangle$ for a TM $M$, $w \\in \\Sigma^$ and $n \\in \\mathbb N$ in some fixed order (e.g. lexicographic order). When looking at such a triple, $M^$ would simulate $M$ on $w$ for at most $n$ steps. If $M$ halts on $w$ within these $n$ steps, $M^$ prints $\\langle M, w \\rangle$.", "399" ], [ "That's not how non-determinism works, though perhaps it's how you'd simulate it in real life. Here are several ways of thinking about non-determinism.\nThe genie. Whenever the machine has a choice, a genie tells it which way to go. If the input is in the language, then the genie can direct the machine in such a way that it eventually accepts. Conversely, if the input is not in the language, whatever the genie tells the machine to do, it will always reject.\nHints. The machine computes a bivariate function. The first input is a word $w$, and the second input is a \"hint\" $x$. Whenever the machine faces a non-deterministic choice, it consults the next hint symbol, and operates accordingly.", "125" ], [ "We are promised the following:\n* Completeness: if $w \\in L$ then there is some hint $x$ which causes the machine to accept.\n* Soundness: if $w \\notin L$ then the machine rejects on all hints.\nAccepting computations. An accepting computation is a legal computation (one in which the machine always operates according to one of the choices it is faced with) which ends at an accepting state. A word is in the language iff it has an accepting computation.\nWe can formalize the notion of accepting computation using snapshots. A snapshot is a triple $(q,z,t)$, where $q$ is the current state, $z$ is the part of the word which remains to be read, and $t$ is the contents of the stack. We can define a relation $(q_1,z_1,t_1) \\vdash (q_2,z_2,t_2)$ which expresses that the machine can reach snapshot $(q_2,z_2,t_2)$ from snapshot $(q_1,z_1,t_1)$ in one step. An accepting computation for a word $w$ (for the acceptance condition of emptying the stack) is a sequence $\\sigma_0 = (q_0,w,\\bot),\\sigma_1,\\ldots,\\sigma_N=(q,\\epsilon,\\epsilon)$, where $q_0$ is the initial state, $\\bot$ is the initial state of the stack, $q$ is an arbitrary state, $\\epsilon$ is the empty word/stack, and $\\sigma_{i-1} \\vdash \\sigma_i$ for all $i$.\nAnother equivalent description is in terms of reachability. Consider a directed graph in which vertices are snapshots and there is an edge from $\\sigma$ to $\\tau$ if $\\sigma \\vdash \\tau$. An accepting computation is a path from $(q_0,w,\\bot)$ to $(q,\\epsilon,\\epsilon)$, for any state $q$.", "399" ], [ "This problem can be solved in polynomial time by a product construction. Construct the graph $G^\\prime$ as follows:\n* The vertices of $G^\\prime$ are $(V \\times M) \\cup {#}$, i.e. all pairs of a vertex of $G$ and a state of $M$, together with an extra vertex identified by the arbitrary symbol $#$.\n* For each edge in $e \\in E$ from $v_1$ to $v_2$, add an edge in $G^\\prime$ from $(v_1, m_1)$ to $(v_2, m_2)$ with weight $w(e)$ if and only if there is an edge in $M$ from $m_1$ to $m_2$ that is labeled $\\ell(e)$.\n* For each accepting state $m$ in $M$, add an edge in $G^\\prime$ from $(t, m)$ to $#$ with weight 0.\nThen the shortest path in $G^\\prime$ from $(s, m_0)$ to $#$ (where $m_0$ is the initial state of $M$) gives the shortest path in $G$ from $s$ to $t$ matching $L(M)$.", "433" ], [ "There cannot be a negative cycle in $G^\\prime$, since dropping the $m$ states from the vertex labels would give a negative cycle in $G$, which we are assuming does not exist.\nThis also answers the question if $M$ is a DFA or regular expression instead of an NFA, since these can be converted to an equivalent NFA in polynomial time. We can also directly handle NFAs with $\\varepsilon$-transitions: if $M$ contains an $\\varepsilon$-transition from $m_1$ to $m_2$, add an edge in $G^\\prime$ with weight 0 from $(v, m_1)$ to $(v, m_2)$ for each $v \\in V$.\nFor fixed $M$, the product graph $G^\\prime$ has only linearly more vertices and edges than the original graph $G$. This means that any fixed problem of the form \"find the shortest path that visits edges in such-and-such order\", such as the problems linked in the question, can be solved just as fast as the ordinary shortest path problem asymptotically.\nAs an implementation detail, note that there is no need to actually write down the whole product graph in memory. The vertices and edges can be generated dynamically while running the shortest path algorithm, which allows unused vertices to be skipped entirely.", "433" ] ]

[ 9610, 7411, 3608, 1870, 7519, 5853, 8344, 10587, 10343, 8046, 5473, 5950, 369, 9031, 8945, 2881, 9027, 8600, 8273, 5811, 10546, 211, 11133, 6683, 6826, 133, 6505, 4395, 6687, 6140, 9778, 5721, 1854, 6159, 826, 4186, 2260, 2727, 8057, 8340, 6309, 10620, 9649, 4733, 2799, 4309, 9179, 7251, 9776, 7806, 8992, 820, 7901, 5878, 4322, 8801, 3303, 3164, 6279, 9279, 9339, 9750, 424, 8532, 6232, 165, 3860, 7270, 9936, 425 ]

[ [ "With shrinking wetlands, population of Nepal’s elusive fishing cats is poised to decline · Global Voices\nFishing Cat (Prionailurus viverrinus). Image via Flickr by Dulup. CC BY-SA 2.0\nIn the southern plains of Nepal, a person who is frightened of something is told ‘you’re a wet cat’. But in that region, there are cats that aren’t afraid of water. In fact, it lives near wetlands and mostly feeds on fishes, earning its name as the fishing cat. However, under threats of habitat loss and degradation, the animal’s population is declining in Nepal.\nToday, experts estimate there are approximately 150-200 fishing cats in Nepal, with less than 2,500 fishing cats in the wild, distributed discontinuously in South Asia and South-East Asia, where they've been recorded in Pakistan, India, Nepal, Bangladesh, Thailand, Myanmar, Cambodia, Sri Lanka and Indonesia.\nSkilful at fishing, the cat's technique is simple: it taps the water surface, and when fishes are drawn to the created ripples, it dives in to catch them. Its partially webbed feet, rudder-like tail and water-resistant coat assist it while swimming. Aside from fishing, for which it was given its name, the cat equally devours rats, reptiles, small mammals, and birds.\nIt's #FishingCatFebruary so let's learn a bit about the species! Fishing cats are expert hunters in aquatic habitats. Not only do they have some unique morphological features, they also have tricks up their sleeve! #fishingcats #fishingcat #fishingcatfebruary #worldfishingcatday pic.twitter.com/tEzcMsf951\n— Fishing Cat Conservation Alliance (@fishingcatorg) February 3, 2021\nFirst recorded in Nepal in 1836 by <PERSON>, the middle-sized cat that weighs around 5-16 kilos and is often confused for a leopard cat, has been classified as Vulnerable in the IUCN Red List.\n“Among the 40 wild cat species in the world, the globally-vulnerable fishing cat is the only species spending most of its time in wetland habitat,” <PERSON>, a PhD candidate at the University of Antwerp in Belgium who founded Terai Fishing Cat Project, Nepal, told Global Voices.", "447" ], [ "“Unlike other cats which don’t prefer going underwater, it preys on several species of fishes and other aquatic creatures. So, we call this cat the indicator of a healthy wetlands ecosystem.”\nConservation biologist <PERSON> tweeted:\nI love big cats, but I love small cats too! Follow my friend & colleague <PERSON> as she collects Fishing Cat scats in southwest Nepal.@iRamaMishra was the first publish a thesis on Fishing cats in Nepal & is the founder of the Terai Fishing Cat Project @fishingcatorg pic.twitter.com/EkXkDklm8D\n— <PERSON> ?? (@samanthaiam) April 26, 2021\nOn the cat's behaviourism, <PERSON>, who studied fishing cats in Koshi Tappu Wildlife Reserve and Chitwan National Park, said she “found these cats are exclusively nocturnal in a human-dominated landscape in the buffer zone area of Koshi Tappu Wildlife Reserve,” but that they're also “found active in day hours too in a wilder habitat like in core reserve site of Koshi Tappu Wildlife Reserve and Chitwan National Park.”\nA camera trap image of a fishing cat. Image by Department of National Parks and Wildlife Conservation (DNPWC)/ National Trust for Nature Conservation (NTNC) through <PERSON>. Used with permission.\nFishing cats have been found and recorded in all protected areas in southern plains of Nepal namely Koshi Tappu Wildlife Reserve, Parsa National Park, Chitwan National Park, Bardia National Park and Shuklaphanta National Park from east to west, except Banke National Park. Beyond protected areas, they are found in fish farming areas, sugarcane fields and paddy fields.\nBut threats like habitat loss and degradation have affected the fishing cat population of Nepal. Speaking to Global Voices, <PERSON>, Assistant Conservation Officer with the Nepalese Department of National Parks and Wildlife Conservation, said that “many wetland habitats are being drained and converted to agricultural land and infrastructure development in Nepal”. He added that, in some areas, pollution and excessive fishing are also damaging wetlands. “In some places, fishing cats have been killed for their pelts or for their meat,” he said.\nA fishing cat lives in and around wetlands. Image by <PERSON>. Used with permission.", "447" ], [ "Nepal roars with pride to become the first country to double its wild tigers by 2022 · Global Voices\nA Bengal tiger stares back in Nepal's Bardia National Park. Image by <PERSON>. Used with permission.\nConservationists are upbeat about Nepal slated to become the first country to double its wild tiger numbers by 2022. On National Conservation Day, September 23, 2018, Nepal announced that it has 235 tigers living in the wild. In 2009, there were only 121 tigers in Nepal.\nNepal's latest tiger census is now out, and – DRUMROLL – number of Bengal Tigers in #Nepal has increased to 235 – a remarkable 94% increase since 2009! We are proud to have helped protect these endangered cats. It’s good for conservation & for tourism. ?https://t.co/N1S9Ypj33D pic.twitter.com/eyNxlYyxzu\n— Chargé d’Affaires <PERSON> (@USAmbNepal) September 24, 2018\nIn 2010, at the Tiger Summit in St. Petersburg, Russia, the Government of Nepal along with the governments of India, Russia, Nepal, and Bhutan pledged to double the number of tigers by 2022.\nTigers, revered in Hindu mythology as the mount of Durga, Goddess of Power, have always been a guarded species. As symbols of power and courage, tigers have faced threats due to a declining prey population, poaching, and destruction and degradation of their habitats.\nOnce, nine tiger species (Bengal, Siberian, Indo-Chinese, South Chinese, Sumatran, Malayan, Caspian, Javan, and Bali) roamed in 13 countries, ranging from Turkey to several nations in Southeast Asia. Out of these, the Caspian, Javan and Bali tigers are already extinct. Nepal is known for its Bengal tigers.\nIn the early 1900s, around 100,000 tigers roamed in the wild.", "447" ], [ "Today, the estimated tiger population is around 3,900 globally. India boasts 2,226 wild tigers — the highest number in the world.\nTigers are found in Nepal’s Chitwan National Park, Bardia National Park, Banke National Park, Shuklaphanta National Park, and Parsa National Park. Earlier, Nepal’s Chitwan National Park was declared the first park in the world to be accredited by Conservation Assured Tiger Standards (CA|TS) in the year 2015.\nCumbersome counting\nTigers are difficult to track because of their elusive nature. According to noted tiger expert Dr. <PERSON>, in the 1960s, officials in India, Nepal, Bangladesh, and Russia assumed that just as human fingerprints are unique, paws of a tiger must differ. They thought they could count tigers by counting their tracks, but the method was flawed.\nWith technological advancements, tigers these days are counted by their unique stripe pattern on their flanks, automatically captured by camera traps placed along tiger trails. The following video reveals how tigers were counted in Nepal, where over 300 field workers spent 16,811 days with 1,643 camera traps and then analyzed tigers’ stripes based on the footage:\nHowever, back in 2016, Dr. <PERSON> expressed skepticism about the counting method in his article “The Trouble with Tiger Numbers“:\nThese groups (the WWF and the Global Tiger Forum) aim to increase the number of tigers to 6,000 by 2022. But their tally, based on official estimates, relied on flawed methodologies, including the use of statistically weak extrapolations from tiger photographs and field counts of spoor.\nTiger conservation initiatives in Nepal\nNepal has led the global tiger conservation movement with recent census results showing increased tiger numbers.\nThe Government of Nepal, together with conservation partners, has initiated several measures to save these magnificent species. According to the paper “Tiger Conservation Initiatives in Nepal”, Nepal has established the National Tiger Conservation Committee and the South Asia Wildlife Enforcement Network.\nNepal has also signed a memorandum of understanding with China for biodiversity conservation focused on curbing illicit wildlife trade, including tiger parts. Nepal’s declaration of Banke National Park as a protected area has also provided larger territory for the tigers. Estimating the abundance of tigers and its prey base (the availability of food in any given habitat to support a predator) will help assess the effectiveness of conservation interventions and formulate plans for future management.\nAdditional measures have been crucial for increasing tiger numbers such as training park and protection staff to use real-time SMART (Spatial Monitoring and Reporting Tool) technologies and the formation of community-based anti-poaching operations to enhance patrolling.\nGrassland management has also been crucial for conservation.", "447" ], [ "Amidst the Trauma of the Great Earthquake Nepalis Celebrate Unprecedented Conservation Successes · Global Voices\nNepal's Chitwan National Park is home to the second largest population of greater one horned Rhino (Rhinoceros unicornis), an endangered species. Image by <PERSON>\nAmidst the gloom and tragedy caused by the April 25 earthquake that killed 8,000 people and caused damage affecting millions of people, conservationists in Nepal have a reason to celebrate. This year’s rhino census has highlighted incredible strides in rhino conservation with the number of one horned rhinoceroses in Nepal reaching 645: a 21% rise from the last count four years ago.\nThe conservation organisation WWF UK tweeted:\nGreat news! Nepal rhino numbers increase by 21% as we mark another 365 days of Zero Poaching of rhinos #EndWildlifeCrime pic.twitter.com/xKmgjxPqAa\n— WWF UK (@wwf_uk) May 5, 2015\nWith three consecutive years of zero poaching, rhino numbers have increased to 605 in Chitwan National Park, 29 in Bardia National Park, 8 in Shuklaphanta Wildlife Reserve and 3 in Parsa Wildlife Reserve.\nNational #Rhino Count completed. Nepal has 645 wild rhinos (chitwan 605, Bardia 29, Shukla 8 & Parsa 3). 111 Rhinos increased in 4 years #fb\n— बाघ हेरालो (@_BabuG) May 5, 2015\nRhino Horns and Rhino Census\nThe greater one-horned rhinoceros, also called Indian rhinoceros, weighs up to 2.2 tonnes and is poached for its prized horn. Believed to contain aphrodisiac and healing properties, the horn is in high demand in Asian markets. Besides this, the horn is also used to make the handles on daggers in the Middle East.\nAncient Persians believed that rhino horn cups had the ability to detect poison in liquids — also a popular belief in the royal courts in Europe.", "447" ], [ "Likewise, the Vietnamese believe that the horn's powder has cancer-curing properties, while young people use it as a cocaine-like party drug.\nIn spite of the high demand and constant threat from poachers, Nepal’s conservation efforts have revived a rhino population that had dwindled down to 100 in 1966.\nThe rhino census, conducted by the government’s Department of National Parks and Wildlife Conservation and Department of Forests in collaboration with conservation organisations, is essential to inform conservation policy.\nThe count is a tedious task conducted using a sweep operation involving trained observers and Nepal Army representatives riding on elephants. Observers systematically comb through the rhino habitats and record individual rhino information including the sex, approximate age and individual markings together with GPS* locations on data-sheets accounting for the unique and special characteristics of each rhino: horn size and shape, folds present on the neck and rump, and body markings.\nOther Reasons to Celebrate Conservation Success\nA wild yak, spotted by researchers in Limi of Humla district in Far-Western Nepal, gave conservationists another reason to smile. Thought to be virtually extinct bar a small presence in remote regions of China and India the animal was sighted for the first time in almost 50 years in the country.\n<PERSON>, a sustainable development policy advisor, tweeted:\nWild #Yak, thought #extinct since 1970s from Nepal, spotted in Humla district in June 2014. (News released yesterday) pic.twitter.com/ZCUwksiNN3\n— <PERSON> (@kashishds) April 21, 2015\nThe species once found in abundance throughout the Tibetan Plateau, had been viewed as having disappeared from Nepal and Bhutan according to recent studies. These animals, larger in size than their domesticated counterparts, weigh between 500-550 Kgs.\nIn addition to this find, ornithologists found two new species of birds during nest counting in Nepal's Chitwan National Park and surrounding areas last month. While one of the new species belongs to the Robin family, another one is a very rare species: the Kashmir flycatcher (Kashmir Arjunak). Chitwan National Park is home to 24 out of the planet's 36 endangered bird species.\nThus, while the country is healing from the trauma and pain of the great earthquake, these conservation successes represent bright lights in the fog of its aftermath. Such gains in the face of adversity, it seems, can offer a powerful inspiration for Nepalis looking to rebuild and recover.\n*Global Positioning System", "447" ], [ "The return of the rufous-necked hornbill to Nepal · Global Voices\nA pair of rufous-necked hornbills. Image by Flickr user <PERSON>, CC BY 2.0.\nIt took almost 200 years to establish the existence of the rufous-necked hornbill (Aceros nipalensis) in Nepal, last seen in the country in 1829. Wildlife photographer <PERSON> found and photographed a pair of male rufous-necked hornbills on December 21, 2021 in Sim Dhap of Suryodaya Municipality in eastern Nepal’s Ilam District. Naturalist <PERSON> had discovered this bird in Nepal in 1829 and coined the scientific name Buceros nipalensis. Before <PERSON>’s find, these birds were reported to be extinct in Nepal though they were still found in India, Bhutan, China, Myanmar, Laos, Thailand and Vietnam.\n“It’s one of greatest achievements in my wildlife photography career,” said <PERSON> talking to Global Voices on the phone from Ilam district in eastern Nepal. He also mentioned:\nNobody had photographed this bird in Nepal before this.", "447" ], [ "I have also photographed other birds for the first time in Nepal, including the green imperial pigeon and scarlet-backed flowerpecker.\n<PERSON> has photographed four species of hornbills found in Nepal: the great hornbill in Besibazar, Mechinagar in Jhapa district; the oriental pied hornbill in Bansbari Community Forest, Mechinagar, Jhapa; the Indian grey hornbill in Kakarvitta, Mechinagar, Jhapa; and his recent find in Ilam’s Suryodaya Muncipality.\nHornbills of Nepal: (L–R) Rufous-necked hornbill, great hornbill, Indian grey hornbill and oriental pied hornbill, photographed in eastern Nepal. All images by <PERSON>. Used with permission.\nBiodiversity analyst <PERSON> wrote in the Nayapatrika daily about the finding of some rufous-necked hornbills in 1850 and criticised the authors of A Guide to the Birds of Nepal for declaring the bird probably extinct in Nepal. In a response to <PERSON>’s criticism of the lack of research on rufous-necked hornbills, <PERSON>, one of the authors of the book, wrote on Facebook:\nConsidering the complete absence of Rufous-necked Hornbill from Nepal for nearly 200 years, the 2021 sighting of this globally threatened species, by <PERSON> is an important record, which should be published in a peer-reviewed journal with the original photographs. In addition, further surveys are required to establish whether the species is resident in the country or merely an occasional visitor and of the extent of suitable habitat.\nCarol Inskipp, <PERSON> and Dr <PERSON>\nIndicator of a forest’s health\nWhen he discovered it, <PERSON> wrote about this beautiful bird, in 1833:\nThis remarkable and very large species, which I have the advantage of contemplating at leisure in a live specimen, measures from the point of one wing to that of the other, four feet five inches; and from the tip of the beak to the extremity of the tail, three feet six inches, whereof the beak is eight inches, and the tail, one foot five inches.\nNature inFocus Foundation from India tweeted:\n#NiFHiveFeature: <PERSON> photographed a Rufous-necked #Hornbill in Latpanchar, #WestBengal.\nAs the name suggests, male hornbills have rufous-coloured head, neck and underparts, while females are predominantly black in colour.#birdphotography pic.twitter.com/VYiu9Ipm19\n— Nature inFocus (@NatureIn_Focus) December 17, 2021\nTwitter user <PERSON> (@pnkjshm) mentioned:\nOne of largest Bucerotine hornbills. Vulnerable on IUCN Red list with less than 10,000 adults left in the wild.\nRufous-necked Hornbill (Aceros nipalensis)\nFound in NE India & SE Asia. Locally Extinct in Nepal due to hunting & habitat loss#NWW2020 #IndiAves #IndiWild pic.twitter.com/COlx9XFulm\n— <PERSON> (@pnkjshm) October 5, 2020\nThe rufous-necked hornbill is categorized as “vulnerable” by the International Union for Conservation of Nature (IUCN).", "447" ], [ "Nepal’s Vulture Restaurants Are Helping Revive Their Population and Generate Income for Communities · Global Voices\nHimalayan Griffon at Vulture Restaurant, Nawalparasi, Nepal. Photo by <PERSON>. Used with permission.\nThey are big, ugly, and have a bad reputation. Although vultures have been at the center of a love-hate relationship with humans — they are also our natural allies. Vultures are mostly carrion eaters and are a major part of the natural process of death in the wild. By devouring large amounts of flesh, these large birds help limit the spread of bacteria and disease that can otherwise spread from the decaying animal bodies. However, despite their important role as buffers against the potential spread of illnesses, they are often regarded as more of a pest than an important bird.\nAs a 2007 survey in India shows, the population of oriental white-backed vultures (Gyps bengalensis) had fallen to 0.1% of its numbers in the early 1990s. In 2009, western Nepal saw its population of oriental white-backed vultures fall by 25% since 2002. Likewise, the population of long-billed vultures (Gyps indicus) and slender-billed vultures (Gyps tenuirostris) also declined drastically throughout the Indian subcontinent. Unfortunately, this trend is not only happening in South Asia, vulture numbers are decreasing worldwide due to less food availability, collision with man-made structures, and poisoning among others.\nTo combat this decline, some countries have proposed an interesting conservation plan to bring their numbers back up — Jatayu restaurants, or restaurants for vultures.\nA restaurant for vultures managed by communities\nTo conserve vulture populations, vulture feeding stations have been set up in a number of different Asian countries such as Cambodia, India, Pakistan and Nepal.", "447" ], [ "In Nepal, the feeding stations are managed by the nearby communities and have been dubbed Jatayu restaurants, named after the revered character in the Hindu epic Ramayana and the vulture’s Sanskrit name, Jatayu.\nIf you are in Nepal & a wildlife enthusiastic, visiting Jatayu Restaurant will be an experience of lifetime. I was mesmerized. #conservation https://t.co/rENmDgrkkE\n— <PERSON> (@_Re_be_cca) August 3, 2017\nThese restaurants source old and unproductive cattle from farmers and take care of the animals until they die at the animal old-age center. People happily handover their old, unproductive cattle to these restaurants because the animals are well taken care of at the end of their lives.\nA scene from a vulture restaurant in Western Nepal — dead animals are offered to vultures at this site only after ensuring that the carcasses are free of Diclofenac. The vultures had been disappearing owing to the use of this medicine for treating livestock. The vulture numbers were on a decline since the poor birds died of kidney failure after eating Diclofenac laced carcass. After the introduction of these restaurants throughout Nepal's southern plains, the vultures are returning back. And the conservationists are happy! ———- #vulture #vulturerestaurant #diclofenac #vultureconservation #terai #Nepal #conservation #jatayurestaurant #southasia\nA post shared by <PERSON> (@sankuchy) on Oct 4, 2016 at 11:16pm PDT\nWhen these cattle die, they are fed to the vultures — but only after they are tested to ensure that the cattle are diclofenac free.\nDiclofenac, the killer drug behind the mass deaths of vultures\nThe use of diclofenac to relieve pain in livestock had been one of the major causes of mass vulture deaths in Nepal, India and other South Asian countries. Even small doses of diclofenac can be fatal for vultures, causing kidney failure in these birds. As the kidney fails to function, uric acid accumulates in the birds’ blood and crystallizes around their internal organs.\nSince vultures feed in large groups, a single carcass laced with diclofenac can cause the death of scores of vultures.\nThe drug was banned in India, Nepal and Pakistan in 2006 and in Bangladesh in 2010.Thanks to the drug ban and also to conservation initiatives by several organizations including local communities, these ‘critically endangered’ bird species have started to bounce back.\nIn addition, these vulture restaurants have become tourist attractions which draw in both domestic and international visitors, providing nearby communities with an additional source of income.", "447" ], [ "Two white snakes, first of their species in the world, found in Nepal · Global Voices\nOne of the leucistic kraits discovered in Nepal. Photo by <PERSON> and <PERSON>. Used with permission.\nAccording to a research paper published in October 2020, two white-coloured kraits (of the genus Bungarus) discovered during rescue calls in Nepal's southeastern region of Province No. 2, are the first such recorded cases in their species. Kraits are known to be some of the most venomous snakes found in the Indian subcontinent.\nOn April 25, 2020, a pink-skinned, black-eyed wall’s krait (Bungarus walli) was found in the Dhanushadham municipality in the province's Dhanusha District.\n“The snake was kept inside a clay pot,” explained <PERSON>, a reptile rescuer and wildlife photographer who spoke with Global Voices by phone. He added that a villager initially assumed that he was not a rescuer but someone who wanted to profit from discovering the snake. “I had to convince the community members before they allowed me to release the snake into [its] natural habitat.”\nA little over a month later, on June 3, <PERSON> rescued another leucistic snake that had been discovered in Dhanushadham's Kishanpur region. This Bungarus niger species, commonly called the greater black krait, looked similar to the one found in Matiarba in April:\nAn example why you should never use only colors for identifying #venomous snakes.\nAmazing article by <PERSON> and team on first report of #leucism in two species of Krait in Nepal.\nName : Black #Krait ( B. niger) and Wall's Krait (B.", "447" ], [ "walli)\nHighly venomous (Neurotoxicity) pic.twitter.com/PHMFLhRDRI\n— Amod Ghimire ? (@serpentcatcher) October 10, 2020\nLeucism and albinism in snakes\nLeucism, a genetic condition that is often confused with albinism, is caused by either a complete or partial loss of pigmentation, resulting in white-coloured skin. Eye colour, however, is not affected.\nAlbinism, on the other hand, is caused by an absence of melanin, which is what gives skin and eyes their colour. The eyes of albino snakes appear pink because the blood vessels shine through their eyeballs.\nIn a telephone interview, <PERSON>, the lead author of the research paper, noted that either leucism or albinism in venomous snakes makes them more vulnerable: their appearance makes them easy to spot, so they often fall prey to predators, and their inability to camouflage presents them with difficulties in finding food. Moreover, they are unable to thermoregulate properly, which affects their movement and digestion.\nREAD MORE:The first recorded two-headed banded kukri snake discovered in Nepal\nVenomous snakes of Nepal\nThe photographic guide Venomous Snakes of Nepal states that out of the 89 snake species recorded in the country, 17 — including six different species of kraits — are considered highly venomous and dangerous.\nThe Wall’s krait (Bungarus walli) variety has a head, body and tail that is typically shiny black, brownish-black or grey, with numerous narrow white or yellowish bands. It has been recorded in Nepal's southeast lowlands, the Gangetic floodplains of northern India, and Bangladesh's delta region.\nThe greater black krait (Bungarus niger) has a shiny black, brownish-black or dark chocolate head, body and tail with no bands or lines. It has been recorded in the lowlands and lower mountains of Nepal, Bhutan, India, Bangladesh and Myanmar.\nKraits are usually active at night and their bites can prove fatal within as little as 24 hours. The World Health Organization estimates that 20,000 people are bitten by snakes each year in Nepal, and more than 1,000 of them die. Many studies suggest, however, that the figures may be higher.\nAlthough less than 20 per cent of the snake species found in Nepal are highly venomous, people tend to be afraid of all snakes. Quite often, rat snakes — which are non-venomous — are mistaken for cobras, as are wolf snakes for kraits.\nSuch cases of mistaken identity usually result in the killing of these creatures, but awareness programmes and the establishment of snake information centres have helped change people’s perceptions as organisations and individuals alike have been rescuing snakes and educating people about them.", "447" ], [ "Nepal Is Using a Satellite Collar to Track a Snow Leopard Named <PERSON> · Global Voices\nA baby snow leopard in New York's Central Park Zoo. Image by <PERSON>. Copyright Demotix (10/11/2013)\nHigh in the Himalayas one of the world’s most beautiful and elusive cats – the snow leopards – are found. Poached for their fur and bones, only 3,500-7,000 individuals remain in the wild throughout Central and South Asia, appearing as “endangered” on the International Union for Conservation of Nature’s Red List of Threatened Species.\nThe Nepalese government's Department of National Parks and Wildlife Conservation, with support from National Trust for Nature Conservation and WWF Nepal, fitted a snow leopard with a satellite radio collar recently to monitor the snow leopard's movements and learn about its behaviour, movement patterns and habitats in Nepal. <PERSON>, the 5-year-old snow leopard named after a mountain in the Olangchung Gola of Kanchenjunga region, is the second snow leopard to be fitted with a radio device.\nA rare snow leopard has been successfully collared with satellite-GPS technology in Nepal: https://t.co/7unfRMHIPi pic.twitter.com/jOCGTMpCw9\n— WWF-New Zealand (@WWFNewZealand) June 9, 2015\nConservationists believe that the information gathered from the collar will be crucial to conserving the 350-500 animals that roam Nepal's Himalayas.\nA difficult task in difficult terrain\nEven spotting a snow leopard is hard in the harsh, rugged and barren terrain, aided by their thick, pale fur with dark grey to black spots that help the cat to camouflage against the rocky slopes.", "447" ], [ "It took about a year and a half for the experts to put a collar on the second animal.\nOfficials had to wait for more than 20 days and had to change trapping methods to search, capture and fit the satellite collar on <PERSON>.\nHere’s a video of the snow leopard collaring.\nThe region where the snow leopard was radio-tagged is scenic and beautiful, with the world’s third highest mountain Kanchengunga, but it is also infamous for the 2006 helicopter tragedy. A group of 24 including world-renowned conservationists lost their lives in the Ghunsa of Kanchenjunga in a chopper crash while returning after handing over the management of the Kanchenjunga Conservation Area to local communities – a moment to be remembered in the history of conservation.\nThe satellite-collaring of Omi Khangri is not new – tigers, rhinos and even gharials have been radio-collared in Nepal to research their movements.\nAccording to the Saving Snow Leopards Report, snow leopards are in danger from the herders who kill them to protect their livestock:\nEducation programs run by agencies like the Snow Leopard Trust and the Snow Leopard Conservancy to discourage local herders from killing snow leopards are important. Improving herding techniques and coming up with more effective ways of guarding livestock can prevent killing in the first place.\n<PERSON>, local conservation officer and a coordinator of Snow Leopard Conservancy projects in the Everest and Annapurna region of Nepal, writes in a blog post how other incentives are used to protect the animal, such as compensating herders when livestocks have been killed by snow leopard:\nMost of the group members do not own livestock, but some do. If a snow leopard kills a baby yak the owner receives 700 rupees as compensation. 1,500 rupees is given for the loss of an adult.\nWith the study of <PERSON><PHONE_NUMBER> animals that roam Nepal's Himalayas.\nA difficult task in difficult terrain\nEven spotting a snow leopard is hard in the harsh, rugged and barren terrain, aided by their thick, pale fur with dark grey to black spots that help the cat to camouflage against the rocky slopes. It took about a year and a half for the experts to put a collar on the second animal.\nOfficials had to wait for more than 20 days and had to change trapping methods to search, capture and fit the satellite collar on Omi Khangri.\nHere’s a video of the snow leopard collaring.\nThe region where the snow leopard was radio-tagged is scenic and beautiful, with the world’s third highest mountain Kanchengunga, but it is also infamous for the 2006 helicopter tragedy.", "447" ], [ "The first recorded two-headed banded kukri snake discovered in Nepal · Global Voices\nA two-headed common krait.Photo provided by Kaligandaki Hospital and Kamal Devkota. Used with permission.\nDicephaly, the condition that causes a snake to be born with two heads, is already very rare. But when villagers from the Nawalpur District of central Nepal captured a two-headed banded kukri snake (Oligodon arnenis) in October 2018, they hadn't the faintest idea that it was the first of its species. A recent report published in the April 2020 edition of IRCF Journal confirms the discovery.\nTwo-headed banded kukri. Photo provided by <PERSON>, Chitwan National Park, Nepal via Kamal Devkota. Used with permission.\nPolice officers rescued the snake from the villagers while they were taking it to the capital city Kathmandu and transferred it to park rangers from the Chitwan National Park who released it into natural habitat.\nA birth anomaly called dicephaly\nThe banded kukri snakes are named after their sharp, flattened, curved teeth which they use for slicing reptile eggs. They are found in Sri Lanka, India, Bangladesh, Pakistan, Bhutan and Nepal.\nTwo-headed snakes are born due to many reasons like incomplete division of embryo, a fusion of two embryos, temperature, environmental factors and many others. The disorder occurs in just one out of every 100,000 snakes in the wild, and in one out of 10,000 snakes born in captivity.\nBecause the snakes have two heads, they have two brains and two distinct personalities but in most cases, one head dominates the other. Dicephalic snakes have very little chance of surviving in the wild as the heads might fight with each other for food. Also, the two heads make them less agile when catching prey and more susceptible to predators.\nTwo Headed Snake\nIt's called dicephaly\nit happens when an embryo in the early stages of development divides possibly induced by sudden temperature changes,\nenvironmental pollution, or inbreeding.\nWhatever the cause,\nthese unlucky creatures don't live long.", "447" ], [ "pic.twitter.com/NDK5o8WMeM\n— <PERSON> (@Einstein2020) November 26, 2019\nWhile images and sculptures of snakes or serpents are often found adorning the temples and water spouts in the Kathmandu Valley, two-headed snakes are an incredibly rare occurrence. The two-headed banded kukri is only the third twin-headed snake documented in Nepal. The first dicephalic snake – a juvenile checkered keelback (Fowlea piscator) – was documented by <PERSON> and <PERSON> in 1983, while the second case – a common krait (Bungarus caeruleus) – was found in May 2018 in the Kawasoti Municipality of Nawalpur District in central Nepal. It was the first record of dicephalism of a krait in Nepal, and it was studied by Board Member of Nepal Toxinology Association and Save the Snakes Project Manager <PERSON> and his team.\nTwo-headed common krait. Photo provided by Kaligandaki Hospital and <PERSON>. Used with permission.\n<PERSON> spoke with Global Voices about how rare it is to find a two-headed snake:\nHerping [searching for snakes] is not an easy task. In my decade-long career, I have found other interesting cases of snakes but you always don't get what you want. Likewise, these dicephalic snakes are found opportunistically while surveying snakes rather than following any specific methods.\nAccording to <PERSON>, up to 90 snake species have been recorded by various authors in Nepal, among which 18 are considered venomous. While many people, especially in the lowlands of Nepal, die of snakebites every year, a snake has its own role in the ecosystem added <PERSON> who has been working on human-snake conflict mitigation.\n[A snake] plays a vital role to maintain the food web in nature. It also helps to increase the farmer's productivity in the field by eating mice, frogs and other harmful insects. From snake venom, we can produce many different types of medicine, including anti-venom.", "447" ] ]

[ 6553, 10369, 6881, 8555, 9262, 1414, 8906, 1160, 10511, 11341, 7524, 9736, 9189, 6778, 4632, 4709, 6394, 6378, 5037, 1734, 8065, 10526, 9689, 7276, 6535, 9681, 905, 11038, 5455, 9980, 8826, 11317, 6545, 8073, 735, 1083, 9195, 216, 1936, 3264, 3965, 10195, 9506, 8617, 7196, 3382, 346, 3427, 2975, 11216, 3022, 10326, 8963, 4311, 1735, 3041, 6012, 5350, 3262, 5111, 9252, 5385, 5789, 5040, 3218, 7795, 4876, 9781, 4412, 393 ]

[ [ "Deriving Gravitational Potential Energy using Vectors\nHere is my attempt at derivation:\nFirst you must find a vector function for the gravitational force.\nBy the inverse square law, the magnitude of gravitational force between two bodies of mass $m$ and $M$ of distance $r$ apart is: $$G \\frac{M m}{r^2}$$\nThe direction of this force points towards the other body. If you let $\\vec{r}$ be the position vector from the other body towards you, then $\\frac{-\\vec{r}}{\\|\\vec{r}\\|}$ gives you a unit radial vector pointing in the direction of the other body. This can be scaled by the magnitude to give the force vector as:\n$$F(\\vec{r}) = G \\frac{M m}{\\|\\vec{r}\\|^2} * \\frac{-\\vec{r}}{\\|\\vec{r}\\|} = -G \\frac{M m}{\\|\\vec{r}\\|^3}\\vec{r}$$\nNow, potential energy is defined as\n$$ U = -W = -\\int_C F(\\vec{r}) \\cdot d\\vec{r}$$\nThe path along which we take the line integral needs to be from an infinite distance away (which we set as our reference point with zero potential) to our current position.\nThe radial displacement vector $\\vec{r}$ can be broken up into a component-wise displacement vector:\n$$\\vec{r} = x\\hat{i} + y\\hat{j} + z\\hat{k}$$\nThe differential $dr$ is then\n$$d\\vec{r} = dx\\hat{i} + dy\\hat{j} + dz\\hat{k}$$\nSubstituting into the expression for the dot product, we get that:\n$$ F(\\vec{r}) \\cdot d\\vec{r} = -G \\frac{M m}{\\left(\\sqrt{x^2 + y^2 + z^2}\\right)^3}(x\\hat{i} + y\\hat{j} + z\\hat{k}) \\cdot (dx\\hat{i} + dy\\hat{j} + dz\\hat{k})$$\nThis gives\n$$-\\frac{G m M x}{\\left(x^2+y^2+z^2\\right)^{3/2}}dx -\\frac{G m M y}{\\left(x^2+y^2+z^2\\right)^{3/2}}dy-\\frac{G m M z}{\\left(x^2+y^2+z^2\\right)^{3/2}}dz$$\nThis can then be integrated term by term. The limits of integration of each should vary from $\\infty$ to the current position ($x$, $y$, or $z$ since gravity is a conservative force (which can be verified mathematically by checking if the y-partial of the x component and the x-partial of the y component are equal) and thus path you take when computing work done does not matter -- it depends only on the initial and final positions.\nThis gives\n$$\\int_{\\infty }^x -\\frac{G m M x}{\\left(x^2+y^2+z^2\\right)^{3/2}} \\, dx + \\int_{\\infty }^y -\\frac{G m M y}{\\left(x^2+y^2+z^2\\right)^{3/2}} \\, dy + \\int_{\\infty }^z -\\frac{G m M z}{\\left(x^2+y^2+z^2\\right)^{3/2}} \\, dz$$\nThis evaluates to\n$$\\frac{G m M}{\\sqrt{x^2+y^2+z^2}} + \\frac{G m M}{\\sqrt{x^2+y^2+z^2}} + \\frac{G m M}{\\sqrt{x^2+y^2+z^2}} = \\frac{3 G m M}{\\|\\vec{r}\\|}$$\nThen taking potential as the negative of the work done we get\n$$U = -\\frac{3 G m M}{\\|\\vec{r}\\|}$$ However, this is clearly incorrect as there is a factor of three that should not be there.\nDid I integrate incorrectly or am I missing something else?", "483" ], [ "Differential and integral forms of <PERSON>' Law leading to different answers\nI came across an interesting problem in one of my exam preparation worksheets recently. To make absolutely sure that I do not omit any important information from the problem, I have included below a direct screenshot of its introduction.\nI was able to to parts a.) - d.) without issue, but part e.) was where I got confused. It asks:\ne.) Explain the steps that the student must follow in order to derive $\\rho(r)$ from $E(r)$.\nHere was my original solution:\nBy <PERSON>' (Integral) Law, $$\\unicode{x222F} E(r) dA= 4 \\pi r^2 E (r) = \\frac{Q_{enc}}{\\epsilon} = \\frac{\\int_{0}^{r}4 \\pi r^2 \\rho(r) dr}{\\epsilon}.$$ Which leads to $$4 \\pi \\epsilon r^2 E(r) = \\int_{0}^{r} 4 \\pi r^2 \\rho(r) dr.$$\nDifferentiating on both sides, $$4 \\pi \\epsilon (E'(r)r^2 + 2r E(r)) = 4 \\pi r^2 \\rho(r).$$\nSolving for $\\rho(r)$, $$ \\rho(r) = \\epsilon (E'(r) + \\frac{2E(r)}{r}).$$\nHowever, I've also been able to arrive at a different answer by <PERSON>' (Differential) Law. If you define the three axis of this space to be one along $r$ and the other two exactly orthogonal to each other and to $r$, then, unless I'm mistaken, the field will only have any strength in the $r$-dimension due to symmetry conditions.", "474" ], [ "The other two dimensions will be locked at zero for all points along the $r$-axis. However, if one travels slightly off this axis, then there will be a non-zero value again. This implies that the $r$-axis is a line of extrema, and therefore that the two non-$r$ derivatives must be 0 when evaluated on the $r$-axis. That would transform <PERSON>' Law from saying $$\\nabla \\bullet E(x,y,r) = \\frac{p(x,y,r)}{\\epsilon} \\Rightarrow E'(r) = \\frac{\\rho(r)}{\\epsilon}.$$\nSolving for $\\rho(r)$, $$\\rho(r) = \\epsilon E'(r).$$\nThese both can't be true, so I am wondering on which path, differential or integral, I made an error. I assume it's the differential path, but that's really nothing more than a hunch.", "474" ], [ "The current is not directly due to the magnetic field, rather it is due to the electric field that is induced by the changing magnetic field. It is true that the electrons will experience a force from the magnetic field according to the Lorentz Force Law, but this force will always be perpendicular to the direction of motion and therefore will not produce a current. In this scenario, because the magnetic field is changing there will be an induced electric field in the wire, which is what will produce the current.\nTo find the current we need to first find the emf, which is the line integral of the net force around the wire loop. The force from the magnetic field will always be perpendicular to the wire, so the only contribution to this line integral will be the contribution from the electric field.", "395" ], [ "Faraday's Law tells us that the line integral of the electric field around the wire loop will be equal to the derivative of the flux of the magnetic field through the wire loop. Therefore, all we need to do to get the emf is calculate the derivative of flux of the magnetic field, and from the emf we can get the current.\nFaraday's Law is the integral form corresponding to one of the four Maxwell Equations in differential form.\nStarting with the following Maxwell Equation in differential form: $$\\nabla\\times \\overrightarrow{E} = -\\frac{d\\overrightarrow{B}}{dt} $$\ntaking the flux through any open surface $\\Sigma$ on both sides yields $$ \\iint_{\\Sigma}{(\\nabla\\times \\overrightarrow{E}) \\cdot \\overrightarrow{dA}} = -\\iint_{\\Sigma}{\\frac{d\\overrightarrow{B}}{dt} \\cdot \\overrightarrow{dA}} $$\nmoving the time derivative outside the integral on the RHS $$ \\iint_{\\Sigma}{(\\nabla\\times \\overrightarrow{E}) \\cdot \\overrightarrow{dA}} = -\\frac{d}{dt}\\iint_{\\Sigma}{\\overrightarrow{B} \\cdot \\overrightarrow{dA}} $$\nApplying Stokes' Theorem: $ \\hspace{1pt}$ for any vector field $ \\overrightarrow{v},\\hspace{5 pt} \\iint_{\\Sigma}{(\\nabla\\times \\overrightarrow{v}) \\cdot \\overrightarrow{dA}} = \\oint_{\\eth\\Sigma}{\\overrightarrow{v}\\cdot\\overrightarrow{dl}} \\hspace{10 pt}$\nto the LHS yields\n$$ \\oint_{\\eth\\Sigma}{\\overrightarrow{E}\\cdot\\overrightarrow{dl}} = -\\frac{d}{dt}\\iint_{\\Sigma}{\\overrightarrow{B} \\cdot \\overrightarrow{dA}} $$\nwhich is Faraday's Law.\nSo we see that Faraday's Law is mathematically equivalent to one of the four Maxwell Equations in differential form, specifically it is the corresponding integral form. Since the two forms are mathematically equivalent, it doesn't really make sense to say that one form is more fundamental than the other. However, I think that the differential form is a little more enlightening than the integral form because it directly describes the relationship between the E & B fields, without any reference to paths or surfaces.\nNow, if what you really want to know is why the differential form itself holds, in other words, why it is that $\\nabla\\times \\overrightarrow{E} = -\\frac{d\\overrightarrow{B}}{dt}$, then that is a much harder question, and I'm not sure whether anyone knows the answer to it.", "418" ], [ "Let me take you through deriving the boundary conditions. I had a fantastic Prof, who explained this very well. We can derive them by evaluating some of <PERSON>'s equations at the interface.\nBoundary Condition 1\nFirst, let's assume there is a surface charge density $\\rho_{sf}$. Let's begin with <PERSON>' Law: $$ \\oint \\vec{D}\\cdot \\mathrm{d}\\vec{S} = Q_{encl} $$\nWe used the displacement field here, defined as $\\vec{D} = \\varepsilon \\vec{E}$, and $Q_{encl}$ is the charge enclosed by a Gaussian box we're about to draw. Let's make it a cylinder around the interface, of height $h$.\nIn words, <PERSON>' law states that the net flux of an electric (displacement) field in a closed surface is directly proportional to the enclosed electric charge. Our cylinder is the closed surface - let's work the integral out!\nFirst, there are no constraints on our choice of the Gaussian surface's height, so we can take the limit $h \\rightarrow 0 $.", "903" ], [ "This means the surface integral for the curved surface goes to zero, and we're left with the ends:\n$$ \\int_{top} \\vec{D}\\cdot \\mathrm{d}\\vec{S} = (\\vec{D}1\\cdot \\hat{n})A $$ $$ \\int{bottom} \\vec{D}\\cdot \\mathrm{d}\\vec{S} = -(\\vec{D}_2\\cdot \\hat{n})A $$\nwhere A is the surface area of the top and bottom end of the cylinder, the subscript number indicates the medium and $\\hat{n}$ is the surface normal. Note that for the bottom end, the integral is negative as the surface normal and the displacement field point in opposite directions.\nNot forgetting about charge enclosed $Q_{end}$: in the limit of $h \\rightarrow 0$, this becomes equal to the surface charge density multiplied by the area of the top/bottom surface! So, <PERSON>' law becomes:\n$$ (\\vec{D}1\\cdot \\hat{n} - \\vec{D}_2\\cdot \\hat{n})A = A\\rho{surf} $$\nCancelling $A$ and evaluating the dot products, we end up with the first boundary condition for the displacement field vector component perpendicular to the interface:\n$$ \\boxed{D_{1\\perp} - D_{2\\perp} = \\rho_{surf}} $$\nWe could substitute $\\vec{D} = \\varepsilon \\vec{E}$ here. Also, the presence of a surface charge will depend on the type of interface.\nBoundary Condition 2\nFor the next boundary condition, let's evaluate the integral form of Faraday's Law:\n$$ \\oint \\vec{E}\\cdot\\mathrm{d}\\vec{l} = - \\frac{\\mathrm{d}}{\\mathrm{d}t} \\int \\vec{B}\\cdot\\mathrm{d}\\vec{S} $$\nIn words, this states that for any closed loop path, the sum of the length elements times the electric field in the direction of the length element is equal to the time derivative of the magnetic flux through the surface created by the closed loop path.\nSo, let's draw a rectangular loop of height $h$ and length $l$ around the interface. We can split the path integral of Faraday's Law up into a sum of 4 parts, for each side of the loop. Again, we can take the limit $h\\rightarrow0$, which means we are only left with the path integrals parallel to the surface:\n$$ \\int_{top} \\vec{E}\\cdot\\mathrm{d}\\vec{l} = (\\vec{E}1 \\cdot \\hat{n})l $$ $$ \\int{bottom} \\vec{E}\\cdot\\mathrm{d}\\vec{l} = -(\\vec{E}_2 \\cdot \\hat{n})l $$\nwhere $\\hat{n}$ is the unit vector in direction of the loop. Not forgetting about $\\int \\vec{B}\\cdot\\mathrm{d}\\vec{S}$: in the limit of $h\\rightarrow 0$, as the surface area of the enclosed path goes to 0, $\\int \\vec{B}\\cdot\\mathrm{d}\\vec{S} = 0$.", "707" ], [ "Throwing a ball from the surface of the earth so that it ends up in a circular orbit\nAssume the Earth to be a uniform sphere of mass M and radius R. Also let the Earth be stationary initially. Assume further that there is all other stellar bodies are very far away so as to have no influence in this problem.\nA ball of mass m is to be thrown from the surface of the Earth so that it ends up ultimately moving in a circular orbit at a height h from the surface of the Earth. How should the ball be thrown, as in, what should be its initial velocity and what angle $\\theta$ with the radial vector from the Earth's center to its initial position on the surface of the Earth?\nMy attempt at the solution -\nSince the Earth-ball system is isolated, its energy would be conserved. Let the initial speed of the ball be $v_0$ and the final speed be $v_f$. We'll have the following equation:\n$$ \\frac{1}{2}m v_0 ^2 - \\frac{GMm}{R} = \\frac{1}{2}mv_f^2 - \\frac{GMm}{R+h}$$\nNext, we know that when the ball will finally be in circular orbit, the gravitational force will be providing the necessary centripetal acceleration for it to maintain circular motion, which gives us the following equation:\n$$ \\frac{mv_f^2}{R+h} = \\frac{GMm}{(R+h)^2} $$\nBesides, since gravity is a central force, the angular momentum of the ball about the center of the Earth will remain conserved, which yields the following equation:\n$$ mv_0R \\sin(\\theta) = mv_f(R+h) $$\nThat completes setting up three equations for three variables - $ v_0, v_f, \\theta $.", "483" ], [ "Solving them, we would obtain the following values for each:\n$$ v_o = \\sqrt\\frac{GM(R+2h)}{R(R+h)} $$\n$$ v_f = \\sqrt\\frac{GM}{R+h} $$\n$$ \\theta = \\sin^{-1} \\Biggl( \\frac{1+\\frac{h}{R}}{\\sqrt{1+\\frac{2h}{R}}} \\Biggr) $$\nHowever, it is observed that for $\\theta$ the argument of $\\sin^{-1}$ is always greater than or equal to one, being one only if h is zero. The proof maybe carried out by initially assuming that the argument of $\\sin^{-1}$ is less than or equal to one for h greater than or equal to 0, and solving the inequality will yield that h must be less than or equal to zero. So the only acceptable solution is for h to be zero. This just winds up being the case of throwing the ball with sufficient speed tangentially on the surface of Earth so that it keeps orbiting on the Earth's surface itself. Thus, there is no feasible way to just throw a ball so that it ends up in a circular orbit of certain desired radius.\nThe problem is that I don't see any Physical intuition for why this should be true; either that, or I am doing something wrong. Any guidance or help would be greatly appreciated!", "521" ], [ "Cube bouncing off a wall\nAn elastic cube sliding without friction along a horizontal floor hits a vertical wall with one of its faces parallel to the wall. The coefficient of friction between the wall and the cube is $\\mu$. The angle between the direction of the velocity $v$ of the cube and the wall is $\\alpha$. What will this angle be after the collision (see Figure P.1.3 for a bird's-eye view of the collision)?\nThis is Problem 1.3 in A Guide to Physics Problems, Part 1: Mechanics, Relativity, and Electrodynamics. There are things I don't understand in the solution provided in the book.\nThere are two forces acting on the cube. One is the normal reaction $N(t)$, perpendicular to the wall, and the other is the force of friction $F_{fr}(t)$ parallel to the wall\nWe expect that, as a result of the collision, the cube’s velocity $\\textbf v$ will change to $\\textbf v'$. In the direction perpendicular to the wall, the collision is elastic, i.e., the velocity in the $\\textbf{x}$ direction merely changes sign: $v'_x=-v_x=-v\\sin(\\alpha)$.", "512" ], [ "Therefore, the momentum changes by $-2mv\\sin(\\alpha)$ in the $x$ direction. This change is due to the normal reaction $N(t)$\nSo, according to <PERSON>’s second law: $$\\Delta p_x = -\\int_0^\\tau N(t) dt = -2mv\\sin(\\alpha)$$\nwhere $\\tau$ is the collision time. If there were no friction, the parallel velocity component would not change and the angle would remain the same. However, in the actual case, the $y$ component changes and $$\\Delta p_y = -\\int_0^{\\min(\\tau',\\tau)}F_{fr}(t)=-\\int_0^{\\min(\\tau',\\tau)}\\mu N(t) dt$$\nHere $\\tau'$ is the time at which the velocity $v_y$ goes to $0$. So $$mv_y'=mv_y -\\int_0^{\\min(\\tau',\\tau)}\\mu N(t) dt$$\nThe first thing I can't grasp is why the collision is elastic in the $x$ direction. Admitting this, I'm ok with the equation $\\displaystyle \\Delta p_x = -\\int_0^\\tau N(t) dt = -2mv\\sin(\\alpha)$.\nBesides, I don't get why $\\displaystyle \\Delta p_y = -\\int_0^{\\min(\\tau',\\tau)}F_{fr}(t)$. It looks a lot like the previous equation the author got on the $x$-axis, but I don't understand why he considers $\\tau'$ as the time at which the velocity $v_y$ goes to $0$, and why the upper bound of the integral has to be $\\min(\\tau',\\tau)$.", "512" ], [ "Lagrangian equations of motion for ball rolling on turntable\nThe equations governing the motion of a ball of mass m, radius R rolling on a table rotating at constant angular velocity $ \\Omega $ which are derived using <PERSON>'s laws are: (I present these for comparison) \\begin{align} (I+mR^2) \\dot{\\omega}_x &= (I+2mR^2)\\Omega \\omega_y-mR \\Omega^2y \\ (I+mR^2) \\dot{\\omega}_y &= -(I+2mR^2)\\Omega \\omega_x + mR \\Omega^2 x \\ \\dot{x} &= R \\omega_y \\ \\dot{y} &= -R \\omega_x \\end{align} Where $x,y,\\omega_x,\\omega_y$ are absolute values measured in the rotating frame ($x,y$ being positions and $\\omega_x,\\omega_y$ angular velocities of the ball). To express the position, velocity, etc in the inertial $XYZ$ frame we can perform a change of variables: \\begin{align} X=x \\cos \\theta - y \\sin \\theta \\ Y=x \\sin \\theta + y \\cos \\theta \\end{align} The equations written above are correct as far as I know. Now I've tried to derive these equations using the Lagrangian approach, but my equations differ slightly from the above.", "101" ], [ "I'll share my work here:\nWe start with the standard formulation of the Lagrangian equations of motion: $$\\frac{d}{dt} \\left( \\frac{\\partial L}{\\partial \\dot{q_i}} \\right) - \\frac{\\partial L}{\\partial q_i}=Q_i$$ For this system, there are no non-conservative forces doing work at any time so $Q_i=0$ (Assuming no-slip here). Now the kinetic energy of the system is: $$T=\\frac{1}{2}m \\| v \\| ^2 + \\frac{1}{2} I \\| \\omega \\|^2 $$ Where $v$,$\\omega$ are the absolute linear and angular velocities of the ball, $I$ is the moment of inertia of the center of mass. I'll proceed in the rotating frame basis $xyz$, where the position $r$ of the ball is given by $$\\vec{r}=x \\hat{i} + y \\hat{j}$$ Using velocity kinematics in rotating frames, the absolute velocity of the ball is given by: $$\\vec{v}=\\vec{\\Omega} \\times \\vec{r} + \\vec{v}{xyz}$$ Where $\\vec{v}{xyz}$ is the velocity of the ball in the rotating frame: $$\\vec{v}{xyz} = \\dot{x} \\hat{i} + \\dot{y} \\hat{j}$$ So the absolute velocity $\\vec{v}$ after expanding gives: $$\\vec{v} = (\\dot{x}-\\Omega y) \\hat{i} + (\\dot{y} +\\Omega x) \\hat{j} $$ It follows from taking the magnitude of the absolute velocity: $$\\| v \\|^2 = (\\dot{x}-\\Omega y)^2 + (\\dot{y}+\\Omega x)^2$$ The first unknown term in the Lagrangian equations of motion.", "101" ], [ "Newton's Third Law and FreeBody Diagram. Solutions provided\nA force of 14.0N is applied to a block as shown in the diagram below\n!\nIf the coefficient of friction is between the surface and the blocks is 0.35\na) What is the acceleration of the two blocks?\nb) What is the force that the 3.0kg exerts on the 1.0kg block?\nSolutions Given a)\n$\\sum F = 14.0N - 13.7N = 0.28N$\n$\\frac{0.28N}{4.0kg} = 0.07m/s^2 = a$\nb)\n$\\sum F = (1.0kg)(0.07m/s^2) = 0.070N$\n$F_{fric} = (0.35)(1.0kg)(9.8m/s^2) = 3.43N$\n$F = 0.07N + 3.43 = 3.5N$\nConfusion\nHere is the thing, but my never show (probably due to print cost?) the free-body diagrams. I want to understand a systematic way of solving this, that is, draw FBD and then apply <PERSON>'s Second law.", "512" ], [ "I already know that they first considered the whole system as \"one mass\" and they applied the 2nd Law and then the third law on each. I want to do this with a Free-Body Diagram.\nHere is my attempt. I am going to denote the masses as 1 and 3 in the subscripts.\nHere are my freebody diagrams.\nFor the block with mass 3kg\n!\nFor the block with mass 1kg\n!\nMy equations should be\n$\\sum F = F - (\\mu m_3 g + F_{13}) = m_3 a$\n$\\sum F = F_{31} - \\mu m_1 g = m_1 a$\nHere is the problem, if I attempt to solve this I get (add the two equations together)\n$F - \\mu (m_1 + m_3)g - F_{13} + F_{31} = (m_1 + m_3)a $\nIf I were to go ahead and plug in the values I get\n$14N - 13.72N - F_{13} + F_{31} = 4a $\n$0.28N - F_{13} + F_{31} = 4a $\nHow come I can't get the same answer this way? Am I missing another equation? Perhaps a constraint? It would seem to make sense if it happens that $|F_{13}| - |F_{31}| = 0$\nBut when I broke it into components like this, I am dealing with the vectorial components, not the magnitiude. So really vectorically, I need $\\vec{F}{13} = -\\vec{F}{31}$\nSo I actually get if I plug in the vector force\nThank you", "512" ] ]

[ 6801, 8351, 10032, 7397, 10452, 7635, 10177, 4182, 4776, 7652, 7964, 11224, 8018, 3995, 6686, 5752, 7131, 3258, 9697, 5396, 3352, 2043, 5312, 4049, 8816, 2991, 47, 3629, 1966, 10115, 11424, 7750, 5355, 4479, 3160, 2050, 10628, 4014, 1474, 11264, 6088, 7300, 10274, 8109, 9644, 5596, 4983, 2219, 6006, 469, 10394, 5192, 8614, 6716, 11020, 1152, 11301, 1028, 10547, 3070, 6766, 6157, 3135, 6054, 7662, 6961, 2395, 3612, 8623, 6496 ]

[ [ "Nothing Gained But Glory\nA game for 2 players designed by <PERSON> & <PERSON>\nIntroduction\nNothing Gained but Glory in the fifth game in the remarkable Series: Musket & Pike Battle (GMT/Vae Victis)from GMT Games.\nThe battles in the series are set in the era of musket and pike warfare where infantry units armed with pikes had interspersed among their numbers of musketeers and arquebusiers, usually accompanied by wings of cavalry.\nNothing Gained but Glory is set during the Scanian War of 1675-1679. There are seven battles covered in this game: Fehrbellin – June 28, 1675; Halmstad - August 17, 1676; Lund – December 4, 1676; Malmö – June 25-26, 1677; Landskrona - July 14, 1677; and Warksow – January 18, 1678.\nThere is also a \"bonus\" battle from the Second Northern War, Nyborg - November 14, 1659.\nComponents\nNothing Gained but Glory comes in the standard sized GMT box with three full counter sheets, 2 full sized back printed full size maps (22x34) and one half sheet map, rules, two scenario books (one of which contains an extensive history of the Scanian War), player aids to keep track of game information, and a 10-sided die.\nComponents in the box\nThe map graphics are some of the best this series has seen, including the use of decorative elements, such as single trees in clear hexes - these add to the beauty of the maps without distracting from the flow of play.\nSample map detail - note the lovely trees\nRules & Game Play\nIt's worth mentioning that the game has some fairly involved rules. GMT rates them a 6/9 on their scale. The rules are 28 pages long, but are exceptionally clear and concise for a game with this much detail to keep track of, and the rules summary and player aids are both excellent guides. For new players, keeping them at hand is a must, and even old hands will find them useful to keep near.\nA turn follows this sequence:\n* Initiative is determined.\n* Wings are activated\n- Preemption attempts are made\n- Wing commanders can try to change their order status\n- Units in the active wing perform a single action\n* Close combat is declared and resolved, active player first\n* Wings may attempt continuation\n* Rout movement\n* Marker removal (a bookkeeping phase)\nThe Musket & Pike games revolve around command and control of your army's wings. The order status for each wing both constrains what you can do, and when you get to go relative to other wings on the board.\nCommand status chart\nEach turn, the side with the most units under Charge orders goes first. There are a series of tie breakers to determine who goes first; simply stated, wings are activated in order of Charge, Make Ready, Receive Charge and Rally. The game includes an ingenious mechanism whereby someone can attempt to preempt a wing that's been activated in order to act first.", "993" ], [ "If they fail, they get a \"No Continue\" marker for their troubles, meaning they'll only have one activation this turn. Wings that have completed their first activation may attempt to go again, up to two times, subject to preemption each time. In the former instance, the commander is bypassed and has to wait (and will go next, subject to possibly another preemption attempt). In the latter instance, the commander who failed his continuation attempt is flipped to his finished side and the next commander set to go (or a bypassed one) begins their activation.\nThe game ends either after the number of turns noted in the scenario, or at the end of any turn where one side has all their wings under Rally orders, meaning they've left the field. In the former case, victory points are tallied and the difference compared to the scenario's victory conditions. In the latter case, the side that withdrew can do no better than a draw; that said, when a situation becomes untenable on the field, it's perfectly reasonable to withdraw to fight another day, so it fits with the theme.\nNothing Gained but Glory comes with version 5.0 of the Musket & Pike rules, which has minor updates and clarifications to previous versions. One specific change is a new withdrawal rule that allows a unit to withdraw when approached, provided specific conditions are met. Of note, Nothing Gained but Glory includes one city assault scenario (Malmö), which includes assault bridges that have their own special rules spelled out in the scenario rules.\nAssault bridges\nThe musket & pike era of battle relied on commanders being able to control their units, and more importantly keeping them in formation and reforming them quickly after close combat.", "100" ], [ "Introduction\nAll summer they drove us back through the Ukraine\nSmolyensk and Viyasma soon fell\nBy autumn we stood with our backs to the town of Orel\nCloser and closer to Moscow they come - riding the wind like a bell\n- <PERSON>, Roads to Moscow\nFighting Formations: Grossdeutschland Infantry Division is the first game in a new series from GMT Games. Much like the Series: Musket & Pike Battle (GMT/Vae Victis), each game in the series will share core rules and the playbook will have specific game exclusive rules.\nThis inaugural game covers action on the eastern front in WWII between the Germans and the Soviets between 1942 and 1943.\nThis is a two player game designed by <PERSON> of Combat Commander: Europe fame (among other titles). Scenarios run the gamut from approximately 2-3 hours for smaller scenarios to a large double map scenario that could fill an entire weekend.\nComponents\nGMT has recently set some impressive standards in wargame publishing. Mounted map boards for single map games like Washington's War and high quality paper maps for multi-scenario games and expansions such as the recent Combat Commander expansion. Beautiful counters that are both functional and nice to look at.\nIn this respect GMT has delivered the goods again.\nThe box however is of the old school thin cardboard style that GMT has not used in a long time. A small quibble is that they used a standard 2\" box rather than the thicker 3\" box; this is a mild disappointment as there is a lot packed inside. Everything does fit into the 2\" box even using two counter trays, but you'll need to split the card decks to make it even along the top. If and when expansions come to this module of the series, it might not fit.\nThe smaller box shouldn't be seen as a deterrent however. There will be more games in the series and those linear feet of shelf space fill up awfully quickly with the larger boxes. I should know, my closets overflow with games.\nThe maps are very attractive and functional, although I found the colour contrast to be muted when compared here with the Combat Commander maps; as you can in the photo here, the Combat Commander terrain features are more easily seen than with the Fighting Formations maps.\nComparing the maps in Fighting Formations (left) to Combat Commander\nWhat's also abundantly clear here is that the Fighting Formations' maps are larger than your typical Combat Commander scenario.", "993" ], [ "The introductory scenario in Fighting Formations uses a half sheet map like Combat Commander, but the other scenarios are all on full and in some cases even double map sheets.\nThe maps are historical depictions of parts of the eastern front. The scenarios all come with a nice long historical background to give the sense of the events about to unfold on the board.\nAnd... for those who felt they were missing from Combat Commander, yes folks, Fighting Formation comes with tanks!\nYes, it comes with tanks!\nRules\nThe rules span two volumes: the core rules and the playbook. The rules are not short, covering some 24 pages and the 64 page playbook adds about another dozen pages of game specific rules and some optional rules. The rest of the playbook is devoted to the 10 scenarios, designer and historical notes, orders of battle, and a detailed example of play.\nThe index is included at the back of the playbook, which can be a nuisance when you're looking for something that is actually in the rulebook, especially anything to do with the sequence of play, but a quick photocopy of the index page is a quick and easy remedy. What's important is clarity and ease of finding information, which are a hallmark of <PERSON> games.\nEven newcomers to wargaming would have little trouble learning the game from the rules, and veteran Combat Commander players will find a lot of familiar terminology.\nVictory is determined by victory points, which can be earned one of three ways:\n- eliminating enemy units\n- controlling certain objectives\n- exiting friendly units off the map\nThe player with the most victory points when the scenario ends is the winner.\nGame Play\nFighting Formations is a classic hex and counter game in many ways. We have the standard hexes, tanks and artillery pieces with facing and fire arcs, movement modified by terrain, and counters chock full of information. There are even rules for vehicles moving in reverse.\nAn interesting and deliberate omission are any stacking rules (except for vehicles moving in column). One could theoretically place every single unit in the same hex. It would be extremely foolish to do so, but you can if you really want to.\nThe lifeblood of Fighting Formations is the order matrix shown above. In order to do anything, you must select a cube from the order matrix, and the value of the cube limits which orders you can execute.", "993" ], [ "Command and Colors System: Comparative Review of BattleLore, Memoir ’44 and C&C:Ancients\nIntroduction\nBefore I begin, I must state my bias. I am a fanboy. I greatly enjoy <PERSON> system, and I have enthusiastically taught a number of individuals all three games, which all parties have greatly enjoyed.\nI would have loved to include Battle Cry in this comparative review. But as it is OOP, I haven’t been able to get myself a copy to play enough games to do it justice.\nMy logged plays for the three systems are currently, which are the minimum number of plays for each game (as I sometimes forget to log!):\nBattleLore: 13\nMemoir '44: 24\nCommands & Colors: Ancients: 9\nA short description of the Command and Colors System can be found in the wiki at http://www.boardgamegeek.com/wiki/page/Command_and_Colors_Sy...\nAvailability\nBoth BattleLore and Memoir '44 are readily available at most online and local game stores. These are both published by Days of Wonder and consequently are quite easy to find.\nCommands & Colors: Ancients is published by GMT Games and is therefore only available at selected game stores. It can also be found at the GMT Website. Commands & Colors: Ancients is now in it’s Second Edition, and this comparative review has been completed using this Second Edition.\nReview:\nAs I often do, I’m actually going to start with Componants, as this is the first thing you get exposed to.\nComponents:\nOverview\nAs mentioned, being published by Days of Wonder, both BattleLore and Memoir '44 have exceptional component quality. The board is thick, the dice are wooden, the figures are plastic and the cards and counters are made of good stock.\nCommands & Colors: Ancients, being a GMT product, has wooden blocks, board is made from cardboard, dice are plastic and the cards are of good stock.\nBoard\nBattleLore – The Board is thick, solid and double-sided. The reverse side is made specifically for “epic” (double-sized) battles.\nMemoir '44 – The Board is thick, solid and double-sided. The reverse side is used for beach scenarios.\nCommands & Colors: Ancients – Many have griped that Commands & Colors: Ancients board is too thin, is hard to get flat and requires plexiglass to use. Personally, being the owner of plexiglass, I do not have a problem with this anymore. But I do admit that this is a legitimate gripe, as my first couple games without plexiglass was prone to sliding blocks.\nBest to Worst: Memoir '44 – BattleLore - Commands & Colors: Ancients\nFigures\nBattleLore – Nicely detailed and moulded plastic. There are also many different moulds for light, medium and heavy infantry, different cavalry, goblins, dwarves, archers, monsters etc.", "299" ], [ "Each piece has a flag holder, whereby the appropriate plastic banner is attached to show which side the unit belongs to. This leads to the first gripe against BattleLore which is the generic and numerous pieces. BattleLore can take a while to set-up in the attempt to find all the correct figures and a storage solution like the below is highly recommended.\nAlso, being used for both sides, all the pieces are a dull grey. For those with time and painting skills, this creates a blank canvas for some wonderful work, but for the majority of us, simply makes the figures seem a bit dull and generic.\nThe second gripe against the BattleLore figures is that many of the figures are a bit ‘bent’. A guide for fixing these is dropping them in nearly boiling water then shocking them in ice water. url has been kindly supplied by <PERSON> here: http://blog.battlelore.com/bent/en/\nMemoir '44 – Nicely detailed and moulded plastic. Memoir '44 figures come in two different colours and the different sides have different moulds. This gives each side it’s unique look, which again has been improved by meticulous painters. Because there are only a few different moulds per side, set-up is quite quick.\nThe one gripe is again that some of the guns are bent, particularly on the artillery and tanks. This can apparently be remedied following the guide above.\nCommands & Colors: Ancients – Wood blocks. I love the feel of the wood blocks. The stickers have great artwork as well. You will need to spend a few hours putting all the stickers on though, which is a negative. Have I mentioned they are wood? On the negative, you will need a storage solution such as below to make set-up proceed smoothly.", "581" ], [ "This review is the first detailed review I have attempted. I have tried to make this, part review and part resource, for anyone not totally familiar with the game. For this reason I expect readers to skip to the sections that are of most interest.\nImage Courtesy of <PERSON>\nSummary\nGame Type - Board Game\nPlay Time : 20-60 minutes\nNumber of Players: 2-8 (Most commonly 2 players)\nMechanics - Card Driven, Scenario Based, Dice Rolling Combat\nDifficulty - Moderate (Takes 6-12 plays to become totally familiar)\nComponents - Very Good\nThis is the first game I have revisited to do a more in depth analysis, as my first review was minimal to say the least. With over 200 plays of Memoir and the recent announcement of the Air Pack and further expansions, I felt the time was right to revisit the base game.\nOverview\nMemoir '44 is the 2nd game to be released in the 'Commands & Colours' System and like other games in the series Memoir is a scenario based board game. As the title suggests, the theme and setting for Memoir is WWII, and more specifically the D-Day landings and battles that took place in 1944. The majority of the scenarios feature the Germans and Americans although other countries are introduced through the use of Special Forces units.\nThe game uses a double sided, six fold board to represent the battlefield and tile overlays are used to represent terrain. Miniatures are used to represent the forces (units) present in each battle. But more on the components later.\nUnits are ordered through the use of Command Cards and these represent the orders issued by HQ to the troops on the front. Icon dice are then used to determine the results of each attack.\nEach scenario has a listed victory condition in terms of the number of medals that must be captured by each side. Medals can be won by eliminating enemy units or capturing scenario objectives.\nThe base game offers a total of 16 Scenarios. Given that Memoir plays best by playing both sides (see below) and this takes time, Memoir offers pretty good value in terms of the time it will spend on the table.\nThe game features two sides representing the Axis and the Allies, so 2 Player games are most common. However it is possible to play using teams and this can be a great way to teach new players as a team can assess their cards together and discuss possible orders and plans.\nTime to get out of the HQ tent and down into the Bunker.\nThe System\nMemoir uses Command Cards to drive the play and these represent the orders issued to your troops. So in effect each player is acting as a General in charge of the troops.\nEach scenario outlines how many cards each side will receive and these are not always equal. This helps to reflect the nature of each battle.", "299" ], [ "Elements such as surprise, planning, or a lack of reconnaissance can be reflected in the number of Command Cards a side receives. This thematic element isn't made highly obvious by the game itself, but it is the conclusion I have come to with experience. It makes the theme of the game more 'real' for me and this increases my enjoyment.\nOnce a scenario is set-up, the play is actually pretty straight forward. The play is turn based and the side to go first is outlined in the scenario. Each turn begins by playing a Command Card from your hand of available cards. Each Command Card allows a set of orders to be issued and these usually result in moving troops and firing on the enemy. Dice are rolled to resolve each attack, casualties are eliminated and medals are possibly won. The number of dice to be rolled is determined by the unit firing, the range and any modifiers for terrain effects or special battlefield conditions (cover, troop type, etc).\nAt the end of a player's turn they will check to see if they have won the medals required for victory. If not the scenario continues and the turn is completed by drawing a replacement Command Card from the deck. Now it's time for the enemy to return fire.\nThe Battlefield - The Board in more Detail\nMemoir offers a double sided, 6-fold board. One side depicts a grassy field, representing the fields of Western Europe, whilst the other side depicts a beach head, comprised of sea, beach and grass area. The board therefore allows the game to depict battles in two separate settings - inland and beach landings.\nThe board is entirely made up of hexes and only 1 unit is allowed per hex. There are 2 red dotted lines, which serve to break the battlefield up into 3 different sections (left, right and centre). This allows the Command Cards to refer to one or more sections of the battlefield, for the purposes of issuing orders. This is all very simple but also very effective.\nThe final feature of the board is the 6 illustrations of medals at the foot of each Side's board.", "336" ], [ "Image Courtesy of <PERSON>\nThis review continues my series of detailed reviews that attempt to be part review, part resource for anyone not totally familiar with the game. For this reason I expect readers to skip to the sections that are of most interest.\nSummary\nGame Type - Board Game\nPlay Time: 30-60 minutes\nNumber of Players: 2-8 (Most commonly 2 players)\nMechanics - Card Driven, Scenario Based, Dice Rolling Combat\nDifficulty - Moderate (Takes 5-6 plays to become totally familiar)\nComponents - Excellent\nRelease - 2005\nDesigner <PERSON> -( <PERSON>, Battle Cry, BattleLore, Commands & Colours: Ancients, Commands & Colours: Napoleonics, Heavo Ho!, Hera and Zeus, Liar's Dice, Samurai Battles, <PERSON>, Yahtzee Free for All)\nThis review follows on from my review of the base game in the Memoir System. As such I will endeavour to analyse this expansion on its merits and then comment on what it adds to the Memoir ’44 system. I have owned this expansion for well over 12 months now so I have been patient in learning the game before getting this review to you (22 plays in all at this point). I hope it reflects my understanding of 'Eastern Front' and is of use to readers.\nI’ll also highlight the fact that this review will not go into the basic game play of Memoir ’44. I have covered this in detail in the following review and I suggest you read that first if you are unfamiliar with the system - Memoir '44 - A Detailed Review\nOverview\nThe Eastern Front is the first real expansion of note for Memoir '44 (I discount the Terrain Pack as a solid expansion at this point but will revisit it after the Air Pack is in my hands).\nAs the name suggests the Eastern Front focuses on the field battles that took place in that theatre and in particular it allows for the introduction of the Russians and the Finns in several expansions. The expansions cover the time period of ’39-’44 and this is the first real departure from Memoir ’44, the time frame for conflicts has been expanded beyond the D-Day landings of the original game (I recognize that this also occurred in the Terrain Pack).\nThis was probably a necessity for the Memoir System to move forward and I don’t feel it detracts in any way.", "299" ], [ "As one would expect the game offers a range of new figures, tiles and terrain, tokens and scenarios. But most importantly it offers new rules that alter the play.\nThe Components\nPart of what makes Memoir stand out as a game, and Days of Wonder as a Company, are the great looking components that helps one’s imagination run wild with possibilities.\nFigures\nIn all the Eastern Front comes with 70 new figures to allow the Russians to enter the fray. All units follow the standard rules of their unit type unless the Scenario Briefing states otherwise.\nRussian Infantry (70) – The Russian Infantry come in brown (as do all the Russian units), which is somewhat apt given <PERSON>’s view of the masses – bleh. The poses for the Russians are unique to the infantry poses of the German and American Infantry of the base game and the use of a harder plastic is evident.\nImage Courtesy of Merg\nArmour (T-34s) (20) – These units are also unique in design. I don’t have the historical knowledge to know if the sculpt is an accurate representation of the T-34 but I would hazard to guess that they got it pretty close within the limitations of the model size.\nImage Courtesy of <PERSON>\nArtillery (ZIS-2 Gun) (6) – These are perhaps the coolest looking of the new figures, if for no other reason than they are so superior in quality compared to the artillery offered in the base game. The harder plastic ensures that the barrel is not as flimsy as a Russian Soldier’s eyelash (one of my few component complaints with Memoir ’44) and the design ensures that the artillery point at the enemy in a threatening manner.\nImage Courtesy of <PERSON>\nTerrain\nThe Eastern Front offers 10 new terrain tiles to freshen up the gaming experience and offer realistic situations found on the Eastern Front.\nImage Courtesy of matthew.marquand\nTrenches – The artwork on these tiles is functional at best and at worst, a little confusing as to what it is meant to be. Either way though trenches are a welcome addition.\nMovement – Infantry and Armour must stop when entering a trench and Artillery cannot enter trenches at all.\nLine of Sight – No effect\nBattle – Infantry and Armour that attack a unit in a trench suffer a -1 dice penalty. Armour may not battle when in a trench.", "581" ], [ "Introduction\nI've never played We the People, the game this is based on, and the American Revolutionary War isn't my usual area of gaming interest; however, given its pedigree, I really felt I had to take the opportunity to get this game.\nThis review is about Washington's War from GMT Games. The game was designed by <PERSON>, who has a storied career in game design with well over 60 titles to his credit (including expansions and modules). I find it not a little ironic that despite my over three decades of gaming that this is the first time I've either owned or played a <PERSON> design!\nThe advertised playing time is 90 minutes. This is the first GMT game I can recall with the estimated playing time on the back of the box. I applaud this move from GMT and hope they continue this with future releases.\nTheme\nWashington's War is a card driven game about the American Revolution, with the forces of King <PERSON> fighting American colonists fighting for independence.\nComponents\nLet's have a look inside the box.\nThe game features a gorgeous linen finish mounted board depicting the eastern portion of the United States (and a small piece of Canada).\nThe counters are nice and thick, reminiscent of GMT's recent Deluxe Twilight Struggle. It has British and American forces, in a similar style to the unit counters of Here I Stand. In addition, there are leader counters (both standard sized and stand up sized versions so the decision of which one to use is up to the individual players).\nThere are a large number of political control markers to show which side controls any specific area on the map. The state abbreviations are inside the circles, so for those who aren't as familiar with US geography as they might like, I recommend the solution <PERSON> introduced me to for Unhappy King Charles! of using bingo tokens which have the benefit of being transparent.\nThe cards are of the standard excellent quality we've come to expect and enjoy from GMT. The deck is roughly 50-50 events and ops cards, with the ops cards being divided into 1, 2, and 3 ops point cards.\nThe dice are perfectly functional, but not as pretty as the dice I'm used to from GMT.\nThe rule book is clear and concise, and in keeping with the latest releases such as is in colour and full of examples. In addition, there's a play book and 2 copies of an identical double sided player aid.\nRules and Game Play\nVictory Conditions\nWinning can happen one of two ways. First, elimination of all enemy combat units on the board (British win = all American and French in US and Canada are eliminated, American win = all British units in the 13 colonies eliminated).", "92" ], [ "Second, after the North's Government Falls - War Ends special event strategy card, in which case a political control victory is determined. In a political victory, the Americans win if they control 7 or more colonies, and the British win if they control 6 or more colonies. Canada is included in the colony count. Control of a colony depends on political markers - whoever has the majority controls the colony. Note that if both sides are tied, or \"both sides win\", then the British win.\nOk, now that I know the victory conditions, how do I play?\nWashington's War begins with both players placing their starting forces and political control (PC) markers on the map as per the scenario instructions. Then the American player adds 1 PC marker in each of the 13 colonies in any space that's available. Then the British add 2 more PC markers with certain restrictions.\nOnce the board is set up, play begins with the following turn sequence:\n- reinforcement phase\n- strategy cards\n- strategy phase\n- winter attrition phase\n- French naval phase\n- political control phase\n- end phase\nReinforcement Phase\nDuring the reinforcement phase, generals in the captured general box is moved to the reinforcement box, and reinforcements on the turn track are deployed on the board.\nStrategy Cards\nEach player is dealt 7 cards for the coming turn. The American always get the first card, and reshuffles occur as needed. There are some cards which are added at specific junctures in the game.\nStrategy Phase\nThe American player decides who will go first in the turn, unless the British player preempts this by the play of a major or minor campaign card (see \"What can I do with my cards\", below). Players then alternate until both are out of cards. It's possible that one player may run out of cards before their opponent thanks to events, in which case one player will have the benefit of playing out their turn uninterrupted by their opponent.\nWinter Attrition Phase\nDuring the winter, all units are checked for attrition. The French, Americans and British all have different attrition conditions.\nFrench Naval Phase\nAfter winter attrition, the American player relocates the French naval unit to any blockade zone they wish.", "597" ], [ "Infidel: The Supremacy of Cavalry in the Crusader Era - 11th-12th Century\nA game for 2 players designed by <PERSON> and published by GMT Games\n“He knew from experience that true and obvious ideas, such as the ineffable wisdom and judgment of the Great God Om, seemed so obscure to many people that you actually had to kill them before they saw the error of their ways...”\n― <PERSON>, Small Gods\nIntroduction\nIn the early days of my wargaming experience, I was interested in virtually any and every subject under the sun. Ancients. World War II. WW III (it was the 1980s and the Cold War was on). Napoleonics. SF and Fantasy themed wargames.\nBack then, whenever I acquired a game, I would often skip the rules and the game and go right for the designer notes and see which books were listed in the bibliography. Sometimes I’d come home armed with a stack from the library and learn a little more about the history the game was portraying.\nOne game that caught my attention back in the day was The Crusades by SPI. I wouldn’t say my delving into the history of the game was exceedingly thorough, but the high points of the first and third crusades were well tended to with that game and its bibliography.\nFast forward several decades later to now. My personal preferences for wargame subjects has become better established, but there are still times where I like to return to topics old and new that interest me.\nInfidel is the second entry in the Men of Iron tactical game series and includes six battles spanning almost a century from 1097 to 1191.\nComponents, Rules, and GameplayPhoto credit: <PERSON>\nInfidel is the second game in the Men of Iron series, and not unlike the series (GBOH), having played will help you learn this one, as well as the third game in the series, .\nThe game includes what you see in the image: two back printed maps, two sheets of counters, the rules and play book, the associated charts, and a pair of 10 sided dice.\nFor those who have played any of the GBOH games, the rules in this system are significantly less complex.", "993" ], [ "The rule book is only 16 pages long and that includes an example of play. If you're an experiential learner like me, having the pieces out on the map as you're reading in order to understand what's going on under the proverbial hood is a great help.\nThe pace of the game is driven by a system of command activations. Units that are part of the same group are known as a Command. The active player selects one of the leaders on their side and then all units of that Command (nicely marked with a coloured stripe) can be activated. Once all your units have been used, you can attempt a continuation, which is to say, carry on by activating another of your leaders and going again with a different Command. The opponent has an opportunity to seize command and activate and use one of theirs instead.\nThis gives the game a nice flow because it's not an automatic IGO-UGO model. The ability to attempt a continuation, or conversely, to prevent that from happening, reminds me somewhat of the (although to be fair it's different because there you can activate the same leader twice in a row) .\nThe battle book contains the scenario setup rules, and also includes historical notes about the battle and its outcome.\nA nice touch is that for each battle there's an approximate play time listed (e.g. \"Playing time ran about 2 hours for the playtesters.\") Some of the scenarios have suggestions for play balance, and some warn about being best suited for experienced/advanced players.\nThe six scenarios are (and here I simply quote the GMT website):\nDorylaeum (1097) : The Crusader line of march, including the people’s Crusade and <PERSON>, as well as all the great 1st Crusade Leaders, are “ambushed” by <PERSON> and his crack Seljuk cavalry.\nAntioch (1098) : The exhausted, starving and depleted Crusaders – they had few horses left – have just taken Antioch and are now faced with a large Turkish army, under <PERSON>, sent to retake the city.\n<PERSON> (1099) : The Crusaders, having seized Jerusalem, turn south to fend off the suddenly active large army of The Fatimids, with their crack Mamluk heavy cavalry.\n<PERSON> (1104) : <PERSON> of Edessa seeks to maintain control of his little kingdom in northern Syria, something <PERSON>, <PERSON> of Damascus, is not happy to allow. One of the first major Crusader defeats.", "993" ], [ "Commands & Colors: Napoleonics\nA game for 2 players designed by <PERSON>\n\"There are but two powers in the world, the sword and the mind. In the long run the sword is always beaten by the mind.\" <PERSON>\nIntroduction\nHello and welcome to the latest edition of Roger's Reviews. I've been playing board games since I was a wee lad and wargames for over thirty years. I've long been a fan of <PERSON> engaging and easy to absorb commands and colors system. Of the games that use the same or at least very similar core mechanics I've also played Battle Cry, Memoir '44 and Battlelore.\nCommands & Colors: Napoleonics (C&C:N) is a tactical battlefield game pitting two players against one another in a Napoleonic setting. As with other games in this series, hand management is key to your success. Good tactics and the occasional lucky die roll don't hurt either!\nComponents\nCommands & Colors: Napoleonics comes in the 3\" deep GMT box and it is simply packed with components.The box weighs a little over 4.5lbs in no small part due to the large number of wooden blocks that come with the game.\nBlocks blocks blocks!\nComplementing the nice wooden blocks is a beautiful green mounted map board with the name of the game in the centre of the map. I'm used to seeing the name of the game on a wargame map, but it is a little unusual to see it so centrally placed here. It immediately made me think of various indoor sport leagues having the team's logo in the centre of the playing area. No need to fret though, it doesn't detract at all from playing the game, and it'll often be covered by terrain tiles anyways.\nThe battle arena!\nSpeaking of terrain tiles, the base game comes with 56 double sided terrain tiles showing everything from forests to rivers to be used in the fifteen scenarios that come in the playbook. There is also a deck of 70 cards with the various commands you'll be able to use in your quest for victory, 8 dice, rules, the aforementioned scenario playbook, various player aids and many many sheets of stickers. I admit up front that having terrain tiles rather than separate scenario maps both allows for the very nice mounted map board and ability to create your own scenarios (if you're so inclined) as well as reducing costs for artwork and separate maps. However, I find having to sort and place terrain tiles on the map somewhat of a nuisance; this is one of those uncommon instances where I would actually have preferred individual paper scenario maps like in the Combat Commander series.\nThe box is packed full of Napoleonic gaming goodness!\nHere's a key difference between the other games in the Borg family and the Commands & Colors (C&C) series (either Ancients or Napoleonics).", "92" ], [ "Whereas Battle Cry et al have plastic miniatures to represent the units, the two C&C series use wooden blocks which require a sticker on both sides (as they'll be upright and visible to both players). The resultant armies are lovely to look at, in many ways easier to sort and store than miniatures, but be prepared my friends to spend literally hours getting your armies all set up. The dice are likewise blank and you have to put stickers on the six faces. There is a guide in the rule book on how to distribute these stickers for those who want specific guidance.\nA note about the blocks and stickers: be prepared to devote several hours of painstaking effort to get all your blocks finished on both sides. It took me around four hours to get it all done.\nSorting blocks by color.\nThe first stickers are applied!\nThe French army begins its rassemblement.\nProgress!\nThe French army is complete!\nOf course, it's not strictly necessary to do all your blocks. You could use one block of each type and sufficient blank blocks to fill the units strength. You could also lay them flat which would only require stickers on one side. So, if you're keen to get playing sooner rather than later, you can use this handy shortcut. Just don't expect that you won't have to eventually get all your blocks finished.\nOn the right, two alternatives to putting stickers on everything.\nThe dice need to have stickers applied too.\nA note of caution. that once you get all those stickers on their blocks and the terrain tiles punched out you'll have a Tetris-like challenge getting everything back into the box. Many people resort to external storage solutions for the C&C sets. For instance, my friend <PERSON> stores his complete C&C Ancients series in a large Plano tackle box, with all the various armies sorted by type in their own compartments. The organizational effort is well worth it and will pay off time and again for setting up a game.\nEverything in ziploc baggies. It all fits though!", "84" ] ]

[ 7437, 2560, 4807, 1730, 3638, 3931, 10044, 9901, 7618, 3001, 2320, 11171, 5130, 8226, 9698, 3235, 3979, 10414, 3889, 11419, 2569, 7903, 6611, 7457, 3582, 7453, 5999, 2857, 10286, 7714, 2179, 2744, 8586, 3571, 8145, 3209, 848, 6815, 2022, 2131, 45, 11222, 3723, 3861, 6210, 1221, 9533, 4781, 9090, 7425, 5285, 3075, 6582, 5006, 7987, 6354, 4225, 4941, 1212, 3424, 9615, 778, 5569, 3622, 8093, 7133, 5106, 458, 10880, 5231 ]

[ [ "Easy Upgrades for Ender3 2020\nIntroduction: Easy Upgrades for Ender3 2020\nHi All,\nEnder3 is a great DIYer's 3D print to get started with 3D Printing. Recently, I bought a Creality Ender3 - 3d printer. Before buying I watched many videos on Youtube, talking about it.", "729" ], [ "In these videos, the experts share a lot of insights, how-to-fix issues, and upgrades on Ender3. There have been some improvements and some of the upgrades are not needed\nIn this article, I have combined the best recommendation, that I could find for Ender3, and based on my experience, I want to share 8 must upgrades, that every newbie should perform, as soon as they get a new ender3.. You do not need additional hardware like screws etc as the printer helps to print these upgrades\nStep 1: The Filament Holder\n* As per the installation guide, one is instructed to mount the spindle on the top of the frame\n* Because of which the filament brushes on the Z-Axis and is not free flow\n* To avoid this mount the filament holder on the side as shown.\n* This maintains at-least 5mm gap between the filament and the z-axis, enabling a free movement of the filament\n* This method does not need any additional upgrades\n* Caution: with this mod, you may not be able to go to the full height for your prints, I have been printing upto 180mm heights without an issue\n* You can mount the filament on standalone https://www.thingiverse.com/thing:2375835\nStep 2: Bed Leveling and Adhesion\n* Two of the biggest problem with Ender3 is bed leveling and adhesion\n* Even if you get a bed that is perfectly flat, when you adjust the bed levels 3 adjustable screws\n* The bed is no longer flat and it becomes difficult to print\n* To fix this issue, I used a glass from an old photo frame\n* The photo frame glass was about 1.5MM thickness, same as the current bed so I didn't adjust the z-Axis\n* And did not crack at 50 degrees for PLA, maybe with higher temperatures, it could crack\n* If you do not have the right-sized glass photo frame, you could get a new piece from a local glass seller\n* I recommend going for a 3mm or 4 mm glass piece and adjusting the z-axis\n* To increase adhesion to this glass, I have used simple masking tape and applied some glue stick on it\n* This increases the adhesion to the bed and the prints do not fall of while printing\nStep 3: Z-Axis Support\n* When you assemble, you will notice that the Z-axis stepper is 1 to 2 mm in the air\n* The spiral rod is not well supported and can bend over time\n* To fix the issue, I downloaded stl files for Z-spacer side v2 and Z-spacer bottom v2 from Thingiverse\n* The V2 has these groves that fit in the metal channels for easy installation\nLink : https://www.thingiverse.com/thing:2925230\nStep 4: Power Supply Silencer\n* Ender3 is not a silent printer, so to lower some sound from the power supply\n* I printed fan silencer from link https://www.thingiverse.com/thing:3328495\n* You can use the same screws that are holding the fan in-place\n* Unscrew one at a time and fix the silencer\n* Tip :\n+ You would see many in 3D community to replace the power supply to a certain brand,\n+ For now, let's not invest more in the printer\n+ Use the power supply as is, till it goes bad and then change it\nStep 5: LCD-PCB Cover\n* The LCD/PCB is not housed in a case, this makes it vulnerable\n* To prevent any accidental damages, we need to cover it with a case\n* Since I had just started this journey, I did not have longer M3 screws, so found a stl file that use the existing M3 screws of the printer\n* Link to the file https://www.thingiverse.", "116" ], [ "CR-6 SE 3D Printer Improvements\nIntroduction: CR-6 SE 3D Printer Improvements\nUPDATE 23 JULY 2022:\nAdded a few native files for spool holders.\n07 JAN 2022:\nI get a lot of requests for the native Fusion 360 files. So I just posted them here for all. See Step 16.\nUPDATE 18 JAN 2021:\nA member requested a modified filament housing sensor housing to pair with an upgraded extruder. File is at Step 15.\nUPDATE 31 DEC 2020:\nA new version of the bearing pulley wheels has been added. I found a problem where they were losing their grip on the metal bearing. The new version should be slightly tighter when first installing and it also has a small hole added to allow a drop of glue to help keep them in place better. File is at Step 14.\nUPDATE 12 DEC 2020:\nMade a new version of the spool holder. Its universal so no need to change the setup when you move to a different filament spool size. File is at Step 13.\nUPDATE 30 OCT 2020:\nAdded STL files for a 33mm diameter spool holder that was requested in the comments section.\nLet me know if anyone else needs a different size. Files are at Step 12.\n_____________________________________________________________________________\nPROJECT SUMMARY: I'll go through a few glaring problems (IMO) with Creality's newest printer, show you my redesigned components, and lastly how to install it all so you too can vastly improve the usability of your CR-6 SE printer.\nThis is an entry in the Make it Move Contest! Please vote if you like it.\nPROJECT HIGHLIGHTS:\n1. Absolutely no drastic changes or permanent modifications to the printer are needed for this project. In fact, once you print all the new parts, the only thing done to the printer is to remove two screws (and then those same two screws are reinstalled.)\n2. The printer itself is used to make the parts needed\n3. Purchased parts are only 6 bearings, 3 screws, and one LED* ($10)\n(* No soldering or wiring needed. We'll just be using the clear plastic head of the LED)\nFor reference, here's the Kick Starter link that Creality used to promote and do the initial sale of the printers:\nhttps://www.kickstarter.com/projects/1001939425/cr...\nSupplies\n1. (QTY1) M8 Allen Head Screw, 50-65mm Long\n2. (QTY 2) M4 Allen Head Screw, 10mm Long\n3. (QTY 6) Standard Skateboard Bearings (608ZZ).", "116" ], [ "I got These\n4. (QTY 1) Standard 5mm LED\nTOOLS:\n1. Allen Wrenches for the M4 & M8\n2. Wire Snips to cut the leads from the LED\nStep 1: Problem 1: Side Mounted Filament Holder\nThis was the biggest issue for me. By mounting the filament spool holder to the side; the footprint of the printer is unnecessarily huge. This position (and the \"fold-away\" feature) almost doubles the required width space for the printer!\nNow, if you have the room, this may not be an issue whatsoever. For me, it meant the printer sat on the kitchen table, then the kitchen counter, then in front of the TV, and finally out to the garage, until I was able to finish making these modifications. It now sits next to my other printers in my small cramped office space.\nWhile my issue is minor as far as Creality is concerned, something that should be a consideration for Creality to assess is Printer Farms. Small companies may consider this printer as the foundation of a Printer Farm (several printers under one roof cranking out parts for the business). By making these modifications the linear printer density can be increased drastically. (For example: 5 printers fit side by side using my configuration versus only 3 if left in the factory configuration on a standard 8 foot long work bench.)\nMy custom designed parts eliminate this issue (or in the least provide an alternative option).\nStep 2: Problem 2: Filament Sensor\nThe automatic filament sensor is a new addition and a great selling point for this level and price range of printer. (The sensor is the part in the right side of the first image above with two screws holding it in place.)\nHowever it has a serious flaw. The Filament Guides, which are metal (brass most likely), have sharp edges. See second image above. That should be a soft radius not a chamfer. Only a few small prints in and I noticed a pile of filament powder that these sharp edges scraped off. (This is a case where cheap plastic parts would actually work better than going to metal. Better yet would be if they were made of Teflon.", "116" ], [ "Using Ender 3 Pro As CNC / Engraving Tool\nIntroduction: Using Ender 3 Pro As CNC / Engraving Tool\nI made a simple carriage to use Ender 3 Pro as a cnc / engraving tool. I used RS775 DC motor and 19V 4A power supply. RS775 is very successful in acrylic engraving and drilling. I haven't tried making PCBs yet, but I think it will be successful too. I will try as soon as possible.\nI know it is not very convenient to use 3D printers as CNC. However, I had to do CNC engraving for one of my projects. So I gave it a shot and I did it. I had better results than I expected. I think it's worth doing.\nSupplies\n- Ender 3 or Ender 3 Pro or Ender 3 V2 (or any creality 3D printer with same x carrier as ender 3)\n- RS775 DC Motor with Drill Chuck\n- 12-40V 10A PWM DC Motor Speed Controller\n- Titanium Diamond Burrs Bur Bit Set Dremel Rotary Tool Set\n- 12V 10A Power Supply (You can use any power supply up to 24V 10A)\n- 150x150mm Acrylic Sheet (or any material you want to use)\n- DC Power Jack and 4 Pin On-Off Button\n- M4 Screws & Nuts and Wires\nNOTE: Links are banggood affiliate links. If you shop on these links, you will be supporting me at no additional cost.\nStep 1: Circuit and Control Box\nYou can power the RS775 motor directly from the power supply. However, it would be much better to put a speed control circuit in between. Thus, you can set the motor to different speeds for different jobs.\nFirstly, 3D print \"Control Box - A.stl\" and \"Control Box - B.stl\"\nYou can find the files in this thing: https://www.thingiverse.com/thing:4793758/files\nThen make the circuit in the picture and place it in the control box. You can either solder the cables directly to the motor or use a ferrule (cable crimp).\nMake sure it is working and if it does, move on to the next step.\nStep 2: CNC Motor Mount (Carriage)\nSince the motor will rotate at high speeds and will engrave/drill, it must be quite rigid in order to get a proper result. I tried 4-5 different models to make this motor carrier and this was the most satisfied one. It is very rigid as it is directly attached to the screws to which the bearings are attached.", "807" ], [ "I know it is a bit long to set up, but this is necessary for a rigid system.I plan to make a quick-change system in the future, but this carrier is enough for now.\nFirst, 3D print the \"Ender 3 Drill Carriage - A.stl\" file. Use at least 60% infill, no need to use support. Than 3d print the \"Ender 3 Drill Carriage - B.stl\" file. Use supports.\nRemove the hotend completely after the 3D prints are done. Also, unplug the extruder motor cable. This is very important.\nThen completely unscrew the x-carrier and its screws. Place the motor carrier that you 3D printed and mount it to the printer. Then insert the motor, screw in two m4x10mm screws from the bottom and attach the \"Ender 3 Drill Carriage - B\" and finish the process.\nStart the engine and make sure it is rigid. If there is no problem, you can move on to the next step.\nUPDATE <PHONE_NUMBER>):\n@MatessakCZE made a great contribution and made a holder (carriage) remix for ProperPrinting's quick tool change design. You can download the remix by clicking here and you can do a quick change instead of removing and putting all the screws back in each time.\nStep 3: Slicing\nThe way 3D printing and CNC work is actually different from each other. Therefore, it is not possible to use a GCODE file we use for 3D printing for CNC purposes. I will prepare a very detailed guide for preparing GCODE suitable for CNC, but for this article, I will show you how to engraving by making a few settings in the Ultimaker Cura.\nFirst, you need to download the drawing you want to engrave from the internet. This drawing should be as simple as possible. You can use a picture prepared in the form of clipart. I used a vector image of a world map as an example.\nAfter finding your image, you need to convert it to SVG file. You can use online tools such as convertio.co for this.", "16" ], [ "How to Make Lego Technic Compatible Parts in Fusion 360\nIntroduction: How to Make Lego Technic Compatible Parts in Fusion 360\nAttending high school: Homeschool\nWhether you are looking for a discontinued Lego part, or want to make a custom Lego part, this tutorial will help. I have used Fusion 360 to do both. This tutorial will focus on Lego Technic parts.\nMy example will include making a Lego mount for a brushless motor and a servo mount. I used these to make a high powered Lego RC car.\nSupplies\n1. Autodesk Fusion 360 Software\n2. 3D printer (I use the Creality Ender 3 V2)\nRecommended: Digital Caliper\nStep 1: Measurements\nIf you want to use 3D printing to adapt non Lego parts into your Lego design, its a good idea to start by measuring the non Lego part that you want to use. A digital caliper makes this process easier.\nStep 2: Build Your Adapter or Lego Part\nIf you are creating an adapter to a non Lego part, it often works best to create the non Lego side first.\nStep 3: Make Your Part Lego Compatible\nAt this point, you may place your adapter into an existing Lego part (example of the motor mount), or add peg holes or pegs. Lego studs are 8x8x8mm peg holes are around 5mm depending on the precision of your 3D printer.", "737" ], [ "Distance center to center between peg holes should be divisible by 8. Dividing by 8 will give you the length in studs.\nYou can find Lego STL files on printablebricks.com as well as a few other sites.\nStep 4: Set Up Your Part for Printing\nImport your Lego compatible part into your 3D printing utility and set up for printing. I find that PrusaSlicer works better than many other slicers. Depending on the part I use %60 - %100 infill. Add supports and adhesion if needed and send to your printer!\nStep 5: Print Your Part\nStep 6: Post Process\nRemove any supports and file down anything that needs it. Often I need to drill the peg holes.\nStep 7: Install Your Part and Have Fun!\nI installed my Lego parts into a Lego RC car. So far they have held up! My Lego car is much more powerful now with the brushless motor instead of the Lego motors I used to make cars with. Its also easier to steer now that I have a servo to steer my car with.", "646" ], [ "DIY 3D Printed LED Poster | W/ Neopixels or RGB LED Strips\nIntroduction: DIY 3D Printed LED Poster | W/ Neopixels or RGB LED Strips\nI am new to 3D printing and I am in this stage where I am experimenting a lot with my Ender 3 Pro to know it capabilites. Today I am here to show you how to create your own 3D printed LED Poster.\nYou can make yours based on a phrase, or a logo as in my case, using your favorite LED strips, RGB, Neopixels, etc.\nHere I leave you a tutorial with all the information so you can make your own version.\nIf you are a visual learner I know that a video worth more than 1000 words, so here is a 2 parts Tutorial video. (I am a Spanish speaker, so please consider turning on English subtitles):\nStep 1: Skills Required:\nThis project may seem difficult or very complex, but it is definitely not completely, since you will have all the guidance for the construction, it was difficult for me to design it to make life a little easier for you. Any conceptual doubt, you are free to ask it without problems.\nYou should have an understanding of:\n* 3D Printing\n* Using of Fusion 360\n* Handling of cutting tools and drills.\n* How to solder (if you need to join several LED strips)\nStep 2: Components and Parts List\n* Here is the list of what you will need for the whole process:\n- 3D Printer: https://amzn.to/38w59ui\n- LED Strip: https://amzn.to/3nuRZ4N\n- Some Glue and cutting tools.\n- Fusion 360 software.\n- Slicer software (ex.CURA)\nStep 3: Vectorizing Your Logo\n1. Open Adobe Illustrator software.\n2. Drag your jpg (img) of your LOGO.\n3. In the upper menu click on \"image tracing\".\n4. In the upper menu open de options of image tracing.\n5. In advance options, checkmark \"skip white\".\n6. Click on \"Expand\"\n7. Now your logo is vectorized\n8. Save as SVG.\nStep 4: Modeling Your Poster on Fusion 360\n1. Draw a square with the dimentions of the bed of your 3D Printer. (220*220mm)\n2.", "737" ], [ "Open a Sketch, and Insert > Insert SVG > Find your vectorized logo.\n3. Scale the logo so the pieces fix on your 3D Printer bed.\n4. Select the perimeters of your logo and make an outside 8mm offset and inside 1.2mm offset.\n5. Select letter by letter and extrude 1mm up.\n6. Select the borders of each letter (one by one) and extrude 50mm up.\n7. Select the 1.2mm border of each letter and extrude 30mm up (joined).\n8. Select the area of the diffusers and apply a two sides extrude (-30mm , 32mm).\n9. Select the 1.2mm borders of the difussers and apply a two sides extrude joined (-30mm , 50mm)\n10. Draw some rectangles in the union of each letter where you want to pass the LED strips.\n11. Select those rectangles and extrude a cut of +10mm height (LED strips are 10mm normally).\n12. Make shure to make an offset of 0.3mm in every piece union, including diffusors.\n13. This is because the pieces expand and grow a little when printed and they wont fix without the offset.\n14. Save your pieces one by one as STL.\n15. Open them on your slicer and print them.\nStep 5: 3D Print the Pieces\nI used 0.3mm layer height for the black parts so I can reduce the time, and the quality was nice.\nI used the standard quality of 0.2mm layers of Cura settings for the diffusors (white parts).\nStep 6: Neopixel Option\nYou can replicate my last project (Neopixels LED strip controller): https://www.instructables.com/Smart-Desk-LED-Light...\nAnd make your LED poster smartter, Neopixels will let you control the color of each letter or piece of your Logo, phrase or forms.\nIn this attached article I give you all the instructions to make the PCB, circuit diagram, code and build process.\nI highly recommend JLCPCB to order your custom PCBs so you can make your own version of the project.", "635" ], [ "3D TIC TAC TOE (Laser Cut & 3D Printed)\nIntroduction: 3D TIC TAC TOE (Laser Cut & 3D Printed)\nThis is a 3D Tic Tac Toe Game made with Digital Fabrication techniques. Compared to the traditional game this is a 3x3x3 and played at three levels by two players. And to make the game you will just need a few materials and after Cutting & 3D printing the files, within an hour you can assemble all the pieces without any glue and start playing.\nSupplies\n* 2MM MDF SHEET\n* 3MM Acrylic Sheet\n* Access to CNC Laser Cutting Machine & 3D Printer\nStep 1: Pegs\nThe Pegs have reducing diameter so the Cross X's & Zeros O's do not fall. The pegs are 3D printed with PLA filament. Print 9 copies of the pegs from the file in the attachment, you also print the pegs in different colours. The pegs have 3MM extrusion at the bottom for fitting on the board. Some sanding might be required to finish the piece. If you can not 3D print, you can also make the pegs from wood or other material.\nStep 2: Cross X\nThe game has 3 Sizes of Cross X, 5 each for each level. The cross piece has 8 side parts, top and bottom part. Start by fitting the kerfed side part to the bottom part and then fit the other side end. Do it all for all the sides and then fit the top part. All the pieces have tight finger joints and you should hear snap sound while fitting.\nStep 3: Zero O\nSame as the Cross pieces there 3 sizes of Zeros O.", "646" ], [ "Fit the belt to one of the piece and join both ends and fit the top piece.\nStep 4: Board\nThe game board is laser cut from a 3MM Acrylic sheet. But you can also use colour tinted, frosted acrylic sheet or even MDF sheet. The green lines in the file are engraved for the 3x3 grid. The board 9 cutouts for the pegs to fit and they dimensioned as per the laser kerf so the pegs fit tight enough that one can lift the board with pegs without falling. But some adjustments may be required due to change in the laser cutting machine.\nStep 5: TIME TO PLAY !\nNow it's time to play the game you made. The great thing about 3D Tic tac Toe is that the game can't end in a draw. Since it's played at 3 levels (x,y & z axis) it's more fun compared to traditional game. You can move to higher level one by one or you can also play at all the 3 levels simultaneously. You can make own rules for the game.\nSome links to learn more about 3D Tic Tac Toe Game & Rules\nhttps://youtu.be/FwJZa-helig?t=240\nhttps://static1.squarespace.com/static/5980d56fb8a79b3cf086de1c/t/599aa213cd0f681d5d9489fe/1503306260633/3D+Tic+Tac+Toe+Rules.pdf\nhttps://en.wikipedia.org/wiki/3D_tic-tac-toe\nStep 6: Test Process\nIt took me a lot of trials and iterations in the kerfing pattern and tolerances to make all the pieces fit without glue. Lot pieces broke when they were bent. And making the belt for the zero's O was the hardest. You see all the failed pieces above that were made to achieve the final result.\nAll the dimensions in the files are in MM.\nAll the finger joints in the files have kerf tolerances of around 0.15 MM - 0.20 MM for the tight-fitting. But due to different power & speed settings and different laser cutting machines, trial cut should be done to make slight adjustments if needed.\nThese are some Instructables and resources that helped me in the project:\nhttps://www.instructables.com/Laser-Cutting-Basics/\nhttps://www.instructables.com/Curved-laser-bent-wood/\nhttps://obrary.com/products/living-hinge-patterns\nhttp://steammetry.com/5-useful-living-hinge-template-for-your-next-laser-cut-project/\nhttp://www.cutlasercut.com/resources/tips-and-advice/what-is-laser-kerf\nhttps://www.troteclaser.com/en/knowledge/tips-for-laser-users/bending-technique/\nhttps://markforged.", "438" ], [ "<PERSON> Voice Assistant Using Raspberry Pi Zero W\nIntroduction: <PERSON> Voice Assistant Using Raspberry Pi Zero W\nJust so you know, I’m a very big fan of marvel, and recently their new series LOKI is by far my most favorite series of all time. So, I thought it would be fun to make one of the characters come to life.\n<PERSON> <PERSON> is an AI character in Loki, who works for a fictional agency called Time variance authority which is controlled by <PERSON> the conqueror. Miss <PERSON> can do a lot of stuff in the series, she talks, interacts with other characters, and of course fetch data and information almost like Friday and <PERSON> in Iron man movies.\nSo, that’s what I exactly did.\nBut I did cheat (or let's say borrowed a lot) a lot to get to this point. So, Make sure to read the full instructions to build your own AI <PERSON>. Also, make sure to grab the supplies below to do the project with ease.\nSupplies\nThis are the list of products that can help you do this project with ease\n(Affiliate Link)\n* 3d printer : https://amzn.to/3trVWKw\n* printer upgrades : https://amzn.to/3hbK3Ga\n* Orange filament : https://amzn.to/3DbhpxG\n* Collar Mic : https://amzn.to/3kixsRx\n* Desktop speaker : https://amzn.to/2XR4wIT\n* raspberry pi zero w : https://amzn.to/3B9RkgD\n* sound card : https://amzn.to/3mlMlFo\n* OTG : https://amzn.to/3grDnTc\n* Female DC jack : https://amzn.to/3B2dvFp\n* 5v dc adapter : https://amzn.to/2UFLofA\n* Male Audio jack : https://amzn.to/3yfMnAS\n* Glue gun :https://amzn.to/2WiuKUa\nStep 1: Building Miss Minutes Enclosure\nUsually, I start with electronics and work my way up to building the enclosure but in this instructable, I'm going to approach this project a little differently. First I’m going to make the enclosure and then later fix the electronics within it.\nBefore I started modeling I tried searching if someone has done a similar project already and I found this amazing Miss Minutes clock project by a Thingiverse user PhilippHee. But unfortunately at the time of documenting the project page is down on Thingiverse, I will make sure to update the link once the page is back up.\nAnyway, I had downloaded the STL file a few weeks back. So, instead of me creating the project completely from scratch.", "354" ], [ "I edited and remixed his project for my need by using fusion 360. You can see the images above to see how the image was modified to meet the need for this project.\nStep 2: Multi-color 3D Printing\nOnce the STL file was ready, it was time to print. I took the model into Cura and sliced it. You can either use a single color to print and then paint the eyes and the outlines on top of it. Or change filaments while printing as I did.\nYou can check this link to see how to change the color while printing just using one nozzle.\nThe above images are reference images where you need to pause to change the color of the filament.\n* Initial - Orange filament\n* First change - Black Filament\n* Second change - White Filament\n* Third change - Black Filament\nTo print this model I used PLA and a larger nozzle with a diameter of 0.6mm and a layer height of 0.4mm for faster printing. It approximately took 9 hours for the complete print for this model, during the print I had to change the filament 3 times. But still, I managed to mess it up by not selecting the proper layer height to change the color.\nAnyway, this gave an opportunity to explain, how you could change the colour if you had not used the multi-color 3d printing technique.\nStep 3: Post Processing the 3D Print\nOnce it’s printed I spent few minutes carefully removing the support materials.\nNote: Don't make any large motions while removing the support material, the thickness of the face is very small and can break quite easily.\nYou can just stop here and continue with the rest of the instructable but for me, the color wasn't that appealing so I fixed the color. I used a black marker for the outline and a whitener for the eyes.", "646" ], [ "Auto-Closing Stacking Drawers for 20mm V-Rail Framed 3D Printers\nIntroduction: Auto-Closing Stacking Drawers for 20mm V-Rail Framed 3D Printers\nUPDATE: 07 April 2021:\nSTL files posted, see last step.\nPROJECT SUMMARY:\nThis project was inspired by:\n1. Instructables Member <PERSON> and his Multicolored Organizer Project\n2. Thingiverse member <PERSON> and her Stacking Drawer Design\nMy mashup of those two ideas aims to create ample and organized space for small items all within easy to reach, easy to access, and easy to identify storage drawers intended for 3D printers using 20mm V-Rail as part of their frame like my Creality Ender 5 Pro.\nOnly two items must be purchased (skateboard wheel bearings and clear plastic rounds), while the rest of the parts are created by the 3D printer itself or should be on hand (like rubber bands). Auto-Closing is accomplished by a standard size rubber band and attachment to the V-Rail is through standard 5mm T-Nuts.\nThis Instructable is an entry in the Simple Machines Contest. Please vote if you like it.\n(This auto-closing drawer design is an example of a simple machine featuring Elastic Energy, Torque, and Rotational Work. It best aligns with a \"Wheel & Axle\" simple machine per the contest guidelines.)\nTABLE OF CONTENTS:\nProject Summary\nSupplies\nStep 1: Requirements & Desirements\nStep 2: Design\nStep 3: Illustrated Parts List & Features\nStep 4: 3D Printing\nStep 5: Post Processing the 3D Printed Parts\nStep 6: Build Step I: Gather all Parts\nStep 7: Build Step II: Install Windows\nStep 8: Build Step III: Mount Base to V-Rail\nStep 9: Build Step IV: Install Pivot Pin\nStep 10: Build Step V: Install First Bearing\nStep 11: Build Step VI: Install Drawer\nStep 12: Build Step VII: Install Second Bearing\nStep 13: Build Step VIII: Attach Rubber Band\nStep 14: Build Step XIV: Repeat Steps I-VIII for Next Level\nStep 15: Validation\nStep 16: FINISHED\nSupplies\nMATERIALS:\n1. Skateboard Bearings (608ZZ) (Quantity 2 Per Drawer)\n2. 40mm Clear Acrylic Rounds (Quantity 4 Per Drawer)\n3. 5mm Panhead Screws & T-Nuts (Quantity 2 EA Per Drawer)\n4. Rubber Bands (Size #32 - 3\" X 1/8\") (Quantity 1 Per Drawer)\nTOOLS:\n1. 3D Printer\n2. Allen Wrench For The 5mm Screws\n3. Standard Shop/Hand Tools For Post Processing The 3D Prints (Supports Are Required)\nSOFTWARE:\n1. Autodesk's Fusion 360 (Used To Create The Design)\n2. Ultimaker's Cura Or Other Slicer (For Slicing The Files To Your Specific Printer)\n3. Luxion's Keyshot (Used To Create Realistic Renders like the image with the Instructable Trademarked Logo)\n4.", "858" ], [ "Corel's Video Studio (Used to Create Short Time-Lapse Videos From Still Shots)\n5. Adobe's Photoshop (For Photo Editing)\n6. Microsoft's PowerPoint (For Image Labeling)\nStep 1: Requirements & Desirements\nHere's a list of requirements and desirements in no specific order:\n1. Drawers can not impede the operation of or normal access to the printer\n2. Drawers should have a feature to keep them closed\n3. Since they stack, having a feature to see what's inside would be desirable\n4. Minimize need for purchase parts\n5. Maximize number of 3D printed parts\n6. Minimize cost\n7. Use a variety of filament colors to maximize visual appeal (or use for categorization, ex. Blue Drawer = Q-Tips)\n8. Include a feature to temporarily hold a drawer in the open position\n9. Size the drawer such that the design can fit on a variety of printers (not be specific to only my printer)\n10. Size the drawer's internal space to fit some of the most common tools frequently needed while 3D printing\n11. Make the design compatible to be either Left or Right Handed\nStep 2: Design\nI continue to enjoy working with Autodesk's Fusion 360 for all my personal design projects. (I wish I could use it for work, but am still stuck with CREO). Even with the great value of the free hobbyist license, I use it so much and wanted some of the extra features that come with a full license I recently made the purchase.", "737" ] ]

[ 2175, 1784, 7791, 8423, 545, 9844, 2263, 7164, 1392, 4602, 1434, 3623, 3296, 4511, 6188, 10029, 5441, 9782, 5526, 1844, 8890, 6699, 2378, 3367, 9340, 7923, 4867, 6107, 8312, 9023, 8686, 4550, 10649, 3885, 8411, 1328, 7203, 6205, 7548, 9849, 9248, 4984, 9869, 4803, 9284, 95, 10886, 8463, 5907, 10808, 4988, 3907, 3490, 10304, 7077, 7403, 1460, 2536, 6996, 10377, 9817, 3777, 4214, 10591, 5132, 2732, 7616, 7702, 4718, 4397 ]

[ [ "Here is a diagram with the quantities we need to solve this:\nFrom Kepler's 3rd Law, the \"kronostationary\" satellite---marked by a green dot---is located at a = 1.86 Req, where Req is the equatorial radius and Rpol is the polar radius (Python calculations dumped at the bottom of the post). The NASA PDS Atmospheres Encyclopedia gives values for the radius of Saturn and useful formulas on its latitude page, and a value for the rotation rate on the longitude page.\nAt the planetographic latitude ($\\phi$g) of the location we want, the line of sight (green) forms a right angle with the local vertical (blue). This sets up a pair of similar triangles as shown. From the big one, we have:\n$$ \\tan{\\phi_{\\textrm{g}}} = \\frac{a - R_{\\textrm{cyl}}}{z} $$\nWe can use the equation for an ellipse to express z in terms of Rcyl:\n$$ \\frac{R_{\\textrm{cyl}}^2}{R_{\\textrm{eq}}^2} + \\frac{z^2}{R_{\\textrm{pol}}^2} = 1 $$ $$ z = \\frac{R_{\\textrm{pol}}}{R_{\\textrm{eq}}} \\sqrt{R_{\\textrm{eq}}^2 - R_{\\textrm{cyl}}^2} $$\nWe can then use the pink-red-red triangle to relate $\\phi$c and Rcyl, eliminating z using the equation above:\n$$ \\tan{\\phi_{\\textrm{c}}} = \\frac{z}{R_{\\textrm{cyl}}} = \\frac{R_{\\textrm{pol}}}{R_{\\textrm{eq}} R_{\\textrm{cyl}}} \\sqrt{R_{\\textrm{eq}}^2 - R_{\\textrm{cyl}}^2} $$\nThe PDS Atmospheres formulas relate $\\phi$g and $\\phi$c:\n$$ \\tan{\\phi_{\\textrm{c}}} = \\left(\\frac{R_{\\textrm{pol}}}{R_{\\textrm{eq}}}\\right)^2 \\tan{\\phi_{\\textrm{g}}} $$\nCombining the first and last equations, and eliminating z, gives a surprisingly simple equation:\n$$ R_{\\textrm{cyl}} = \\frac{R_{\\textrm{eq}}^2}{a} = 32362\\ \\textrm{km} $$\nPlugging this value of Rcyl into the equations above gives: - Planetocentric latitude 54.8° - Planetographic latitude 60.1°\nActual visibility and survivability of this satellite are not great. The kronostationary radius would put this satellite within the B ring, which is \"the largest, brightest, and most massive of the rings:\"\nCalculations:\nimport numpy as np\nR_eq = 60268. # km\nR_pol = 54364.", "371" ], [ "# km\nGMsat = 37931206.159 # km^3/s^2\nP_sat = 10.656 * 60.**2. # s\n# <PERSON><PHONE_NUMBER> # km^3/s^2\nP_sat = 10.656 * 60.**2. # s\n# Kepler's 3rd law: a is the kronocentric distance (circular orbit)\na = (P_sat**2 * GMsat / 4 / (np.pi)**2)**(1/3.)\nprint(\"Kronocentric distance,\")\nprint(\" a (R_sat): \", a / R_eq)\nprint(\" a (km): \", a)\nprint(\" altitude (km): \", a - R_eq)\nprint(\" \")\n# solve for R_cyl\nR_cyl = R_eq**2. / a\nprint(\"R_cyl: \", R_cyl)\nprint(\" \")\n# get latitude\nlat_centric = np.arctan(R_pol / R_eq / R_cyl * (R_eq**2. - R_cyl**2.)**0.5)\nlat_graphic = np.arctan(R_eq**2. / R_pol**2. * np.tan(lat_centric))\nprint(\"lat_centric: \", lat_centric * 180./np.pi)\nprint(\"lat_graphic: \", lat_graphic * 180./np.pi)\nprint(\" \")\nKronocentric distance,\na (R_sat): 1.", "371" ], [ "All 2-body systems end up tidally locking each other. In fact, the Earth is slowly going into tidal locking with the Moon, it just takes a lot longer for the larger body to lock with the smaller one (the moon is of course already locked). In your case, it is expected that a binary system of asteroids would be tidally locked.\nI simulated the asteroids orbiting the sun at one AU, where the sun has position {0,0,0} and a velocity which offsets that of the asteroids.\nLet's assume our asteroids have an average density of $~1000\\frac{kg}{m^3}$.", "788" ], [ "Then the mass of asteroid of $3\\left(km\\right)$ diameter with a volume of $\\frac{4}{3}\\pi 1.5^3\\left(km^3\\right)\\approx14\\left(km^3\\right)=14\\times10^9\\left(m^3\\right)$ has a mass of $14\\times10^{12}\\left(kg\\right)$\nWe can estimate the relative velocity by means of an idealized circular motion, in which case $a=\\frac{v^2}{r}$. We also know that the acceleration due to asteroid 2 is $$G\\frac{m}{r^2}=6.674\\times10^{-11}\\left(N \\frac{m^2}{kg^2}\\right)\\frac{20\\times10^{12}(kg)}{\\left(1.5\\times10^4\\right)^2(m^2)}=5.93\\times10^3\\left(\\frac{m}{s^2}\\right)$$ And thus: $$v=\\sqrt{ar}=\\sqrt{1.5\\times10^4(m)\\times5.93\\times10^3\\left(\\frac{m}{s^2}\\right)}=0.3\\left(\\frac{m}{s}\\right)$$\nThis gives us a good aprroximation, and with some testing, it turns out that $0.4\\left(\\frac{m}{s}\\right)$ gives us a good orbit:\nSo, let's use the following statistics:\nAsteroid 1\nMass: $14\\times10^{12}$\nPosition:$\\left(AU,0,0\\right)$\nVelocity:$\\left(0.4\\frac{m}{s},29780\\frac{m}{s},0\\right)$\nAsteroid 2\nMass: $20\\times10^{12}$\nPosition:$\\left(AU,15\\times10^3,0\\right)$\nVelocity:$\\left(0,29780\\frac{m}{s},0\\right)$\nMeaning they have an initial distance and velocity relative to eachother of $\\Delta s=13\\times10^3$,$\\Delta v=0.4\\frac{m}{s}$.\nBehaviour\nOur asteroids have a steady near circular orbit around the sun, the orbit takes about 390 Earth days:\nThe distance between the asteroids fluctuates slightly, both in the short as long term, this is more realistic than perfectly circular orbits. The long term fluctuation is due to the influence of the sun, this gives the distance between the asteroids over 2 earth years:\nTidal locking\nThe asteroids rotate very slowly around eachother, and will almost certainly be tidally locked.\nEccentricity and Stability\nThis configuration is stable over single digit years, the precise configuration needs to change for stability to be maintained over more years.\nFor decades long stability, the eccentricity actually seems to decrease, regardless of the initial situation, however when the orbit eccentricity becomes too low (the orbits become highly circular), the orbits become suddenly less stable, here is the plot over 200 years:\nAs you can see, after 70 years or so, the asteroids start to draw closer together. Increasing velocity accuracy, draws this out,\nLet me know if you need anything else, I love this stuff.\nMy guess is this means it's really difficult to find a stable orbit between such two small objects, however by increasing the accuracy of the velocity, it should be possible for the orbit to be stable for a few thoasand years, though such a configuration would be highly unlikely to occur naturally.", "374" ], [ "Modelling lunar motion in Python\nI'm trying to solve the equations of motion of the Moon in the Moon-Sun-Earth system (equations 1139-1141 here:http://farside.ph.utexas.edu/teaching/336k/Newtonhtml/node130.html)\nMy initial conditions were $ \\boldsymbol{r} = $, where a is the Lunar semi-major axis. The initial velocities were $\\boldsymbol{\\dot{r}} = \\omega a <0, cos\\phi, sin\\phi>$, where $\\omega$ is the Lunar angular velocity and $\\phi$ is the inclination of the Lunar orbit from the ecliptic plane.\nThis is my code:\n```python\nimport matplotlib.pyplot as plt import numpy as np import scipy.integrate as spi\nData\nMoon orbit semi-major axis\na = 384.748e6 # m\nMoon angular velocity around the Earth (27 days)\nomega = 2.6934e-6 # s^-1\nomega = 0.2327 # days^-1\nEarth orbit semi-major axis\na_dash = 149.6e9 # m\nEarth angular velocity around the Sun (365 days)\nomega_dash = 1.9923e-7 # s^-1\nomega_dash = 0.0172 # days^-1\nInitial conditions\nat t = 0,\n[x, xdot, y, ydot, z, zdot] - same as the motion vector\n0.<PHONE_NUMBER> rad = 5.15 deg\nvy = omegaanp.cos(0.<PHONE_NUMBER>) vz = omegaanp.sin(0.<PHONE_NUMBER>)\ninit = [a, 0, 0, vy, 0, vz]\nEquations of motion\nReturns the derivatives of x,y,z (u,v,w) and u,v,w in a vector [xdot, udot, ydot, vdot, zdot, wdot]\nr - states\nrdot = np.zeros(6)\ndef motion(t, r): x = r[0] u = r[1] # xdot or velocity in x direction\ny = r[2]\nv = r[3] # ydot\nz = r[4]\nw = r[5] # zdot\n# the derivatives with respect to time\n# [xdot, udot, ydot, vdot, zdot, wdot] = [u, udot, v, vdot, w, wdot]\n# xdot\nrdot[0] = u\n# udot =\nrdot[1] = 2*omega*v + (omega**2+omega_dash**2/2)*x - omega**2 * x *a**3/(np.sqrt(x**2+y**2+z**2)**3) + 3/2*omega_dash**2*(x*np.cos(2*(omega-omega_dash)*t) - y*np.sin(2*(omega-omega_dash)*t) )\n# ydot\nrdot[2] = v\n# vdot\nrdot[3] = -2*omega*u + (omega**2+omega_dash**2/2)*y - omega**2 * y *a**3/(np.sqrt(x**2+y**2+z**2)**3) - 3/2*omega_dash**2*( x*np.sin(2*(omega-omega_dash)*t) + y*np.cos(2*(omega-omega_dash)*t) )\n# zdot\nrdot[4] = w\n# wdot\nrdot[5] = -omega_dash**2*z - omega**2 * z *a**3/(np.sqrt(x**2+y**2+z**2)**3)\nreturn rdot\nSolve system of ODEs\nt_start = 0. t_end = 5000 t_step = 1 ode = spi.ode(motion)\nBDF method suited to stiff systems of ODEs\node.set_integrator('vode',nsteps=500,method='bdf', rtol=0.1) ode.set_initial_value(init,t_start)\nts = [] soln = []\nwhile ode.successful() and ode.", "380" ], [ "We can use the same expression that is commonly used to estimate the apparent magnitude of a planet or asteroid in the Solar System*:\n$$\\boxed{m=5 \\log \\frac{1329}{d \\cdot \\sqrt p}+5 \\log (D_s \\cdot D_e)-2.5\\log f(F)}$$\nWhere:\nm is the apparent magnitude\nlog is the decimal logarithm\nd is the diameter in km\np is the albedo\nDs is the distance to the Sun in Astronomical Units (AU)\nDe is the distance to Earth in Astronomical Units (AU)\nf(F) is the phase function\nIf we want to apply this expression to the James Webb Space Telescope, the values to use are as follows.\nAs the surface area of the JWST solar shield is $S=21\\cdot 14=294$ square meters:\n$$d=\\sqrt{\\frac{4\\cdot S}{\\pi}}$$\nEquivalent diameter \"d\"\nd = 0.01935 km\nThe satellite hosting the Webb Telescope will be placed in a halo orbit around Lagrange L2 Sun-Earth, a point located 1.5 million kilometers from the Earth (see drawing). The radius of the halo orbit is 0.8 million km.\n$$D_e=\\sqrt{1.5^2+0.8^2}=1.7$$\nDe = 0.01136 AU\nDs = 1.01004 AU\nAs a phase function we will use the usual one:\n$$f(F)=\\dfrac{1+\\cos F}2$$\nThe phase angle \"F\" is calculated using basic trigonometry from the drawing\nIt is obtained:\nF = 27.8º\nAnd we see that the contribution of the corresponding summand is almost negligible:\n$$-2.5 \\log f(F)=+0.06$$\nThe albedo \"p\" of the heat shield will be high, to reflect the maximum amount of heat possible.", "371" ], [ "But since the albedo of the solar shield is unknown to me, I add the table below showing the estimated apparent magnitude value, for different albedo values.\nThe table tells us that the apparent magnitude of the JWST when it reaches its halo orbit around L2 will be of the order of +15 and therefore this should be visible with some powerful telescopes of amateur astronomers.\n*Reference: Binary asteroid population. 1. Angular momentum content, by <PERSON> and <PERSON>\nBest regards.", "758" ], [ "I do not have the book you mentioned, but I could find something in my notes from last year's Classical Mechanics lecture.\nFirstly, if your projectile reaches escape velocity, then it will of course travel away from the Earth forever, which answers your question with $\\infty$. When does this happen? The potential energy of the projectile is given by:\n$V(r) = -\\frac{GMm}{r}$\nWe will escape the Earth's potential, if we have enough energy to reach the potential at $r=\\infty$, which obviously corresponds to $V=0$. So we need at least the potential at the Earth's radius in kinetic energy:\n$K = \\frac{1}{2}mv_0^2$\nTherefore\n$v_{escape}=\\sqrt{\\frac{2GM}{R_E}}$\nWhere $G$ is the gravitational constant, $M$ the mass of the Earth, $m$ the mass of your projectile and $R_E$ the radius of the Earth (which is the current distance of your projectile from the Earth's center). So if the projectile's velocity is higher than this we have an unbound orbit, and there is no maximum height. If it is less than this we have a bound orbit, whose trajectory we need to figure out.\nNow gravitation is a radial inverse-square law force of the form $\\textbf{F}=\\frac{k}{r^2}\\textbf{r}$ where $\\textbf{r}$ is a unit vector pointing radially outwards. Since it is attractive $k<0$ (in fact $k=-GMm$). For these forces a bound orbit will be elliptical, with the center of the Earth at one of the ellipse's foci.", "483" ], [ "The equations I could turn up let you determine the eccentricity $e$ and the semi-latus rectum $h$, which define the ellipse, from the angular momentum and the total energy of the projectile.\n$E = K + V = \\frac{1}{2}mv_0^2-\\frac{GMm}{R_E} \\ \\textbf{L} = m\\textbf{R}_E\\times\\textbf{v}_0=mR_Ev_0\\sin(\\theta_0) \\ h = -\\frac{L^2}{mk} = \\frac{L^2}{GMm^2} \\ e = \\sqrt{1+\\frac{2EL^2}{mk^2}}=\\sqrt{1+\\frac{2EL^2}{G^2M^2m^3}}$\nUsing $e$ and $h$ we can figure out $r_A$ and $r_B$, the distance from the Earth's center to the \"perigee\" and \"apogee\" (the points that are nearest and farthest from the Earth's center, respectively). We do this using standard ellipses formulae:\n$r_A = \\frac{h}{1+e} \\ r_B = \\frac{h}{1-e} \\$\nSince $e$ is between $0$ and $1$, we obviously have $r_B > r_A$ as expected. So the largest height above the Earth's surface would then be $r_B - R_E$. We would be done here... if there was not the possibility that the projectile hits the Earth's surface before reaching the apogee (for example because $\\theta_0>\\pi/2$). I am honestly at a loss when it comes to figuring out whether the projectile reaches the apogee, the perigee or both, but I have a feeling that if it reaches any of the two, it would be the apogee as required. But I cannot figure it out properly right now. When I do, I will edit the answer.", "483" ], [ "All the existing answers nicely explain the issue, but I'll add some numbers to the discussion:\nIn 2018, 112 objects have been launched to orbit. Let's assume a typical rocket mass of 500 t and a payload of 10 t (values for the Falcon 9). Of these 112 objects, 30 were launched into high orbits where part of the rocket exhaust may have escaped Earth's sphere of influence (SOI), and four (<PERSON> Tesla Roadster, InSight, Parker Solar Probe, and BepiColombo) were launched into interplanetary orbits where they and their upper rocket stages, escaped Earth's SOI themselves.\nFor high orbits, we can assume that about half of the payload's mass leaves Earth's SOI in the form of rocket exhaust. For payloads that are launched into interplanetary space, we can assume that an additional 10 tons are sent in the form of the launcher's spent upper stage.\nAssuming that 2018 is a representative year and those guesses are about correct (variations from 0.1 to 10 would be possible),\n* The total launched mass is $5 \\cdot 10^7\\ kg/year$\n* The total satellite mass increases by $1 \\cdot 10^6\\ kg/year$\n* The total satellite mass in high orbits increases by $3 \\cdot 10^5\\ kg/year$\n* The total mass leaving Earth's SOI, from both interplanetary launches and rocket exhaust of high-orbit satellites, is $3 \\cdot 10^5\\ kg/year$\nAs discussed in the other answers, the mass of satellites that stay inside Earth's SOI has no influence on the distance between Earth and the Sun. The only relevant part is the $3 \\cdot 10^5\\ kg/year$ that are launched away from Earth.\nAs you correctly noted, the mass itself isn't relevant, the impulse is, so let's assume that the mass leaves Earth at 10 km/s.", "24" ], [ "The fastest-ever spacecraft to leave Earth was New Horizons at 16 km/s, while a typical Mars transfer takes 6 km/s. Rocket exhaust is typically much slower, on the order of 3 km/s.\nWe arrive at an impulse of $ 3 \\cdot 10^9\\ Ns / year $, or an average force of $ 100\\ N $.\nBut in which direction is the force applied? For interplanetary probes the ejection direction depends on your intended destination and transfer plan, while for rocket exhaust from satellites in high orbits it's pretty much random. All in all, I guess that it will pretty much even out. After all, in 2018 two launches were to higher solar orbits and two were to lower solar orbits.\nIf the force is applied in the same direction in which Earth is moving, it is accelerated and thus lifted into a higher orbit. If the force is applied in the opposite direction, it is decelerated and moves into a lower orbit (closer to the Sun).\nThe orbital energy of Earth is calculated as $ -\\frac{ G \\cdot M \\cdot m_{Earth}}{2a}$, where G is the constant of gravity, M is the total mass of the Earth-Sun system, and a is the semi-major axis (average distance between Earth and Sun).\nThe power at which Earth is accelerated or decelerated is $\\frac{dE}{dt} = Fv$, where F is the force of acceleration and v is the orbital velocity of Earth. We arrive at\n$a(t) = - \\frac{G \\cdot M \\cdot m_{Earth}}{2 \\cdot (E_0 \\pm F v t)} = - \\frac{G \\cdot M \\cdot m_{Earth}}{2 \\cdot E_0} \\cdot \\frac{1}{1 \\pm \\cfrac{F v}{E_0} \\cdot t} $\n$\\frac{da(t)}{dt} = - \\frac{G \\cdot M \\cdot m_{Earth}}{2 \\cdot E_0} \\cdot \\frac{da(t)}{dt} (\\frac{1}{1 \\pm \\frac{F v}{E_0} \\cdot t}) = - \\frac{G \\cdot M \\cdot m_{Earth}}{2 \\cdot E_0} \\cdot \\frac{\\mp \\frac{F v}{E_0}}{(1 \\pm \\frac{F v}{E_0} \\cdot t)^2} $.", "234" ], [ "To find the distance from one star to another, we need three things for both of the stars: their right ascensions, declinations, and the distance from Earth to those stars.\nSo, let's get those things:\nFrom the Wikipedia page on Alpha Centauri:\n$RA = 14^h\\:39^m\\:36.49400^s$\n$DEC = -60^{\\circ}\\:50'\\:0.23737''$\n$R = 4.37\\:\\rm{ly}$ (you gave 4.366, some other sources give 4.367... I'm going to stick with 4.37)\nand for Barnard's Star:\n$RA = 17^h\\: 57^m\\: 48.49303^s$\n$DEC = +04^{\\circ}\\: 41'\\: <PHONE_NUMBER>''$\n$R = 5.958 \\: \\rm{ly}$ (again, you gave a slightly different value, I'm sticking with Wikipedia for now)\nwhere RA is right ascension, DEC is declination, and R is radial distance from Earth to the target star.\nNow, by themselves, it is relatively difficult for us to obtain an actual distance. What I would do is convert these to rectangular coordinates, and then it's a matter of using the 3-d distance formula.\nFirst, however, we need to convert RA and DEC into units like radians or degrees.\nFor right ascension, we can use the general formula:\n$degrees = 15 (h + \\dfrac{m}{60} + \\dfrac{s}{3600})$\nand for declination:\n$degrees = deg + \\dfrac{m}{60} + \\dfrac{s}{3600}$\n(when the declination is negative, however, multiply all terms in the formula by -1)\nSo, for Alpha Centauri AB, we have:\n$RA = 15 (14 + \\dfrac{39}{60} + \\dfrac{36.49400}{3600}) \\approx 219.902^{\\circ}$\n$DEC = -1 (60 + \\dfrac{50}{60} + \\dfrac{0.23737}{3600}) \\approx -60.833^{\\circ}$\nand for Barnard's Star, we have:\n$RA = 15 (17 + \\dfrac{57}{60} + \\dfrac{48.49303}{3600}) \\approx 269.452^{\\circ}$\n$DEC = 04 + \\dfrac{41}{60} + \\dfrac{<PHONE_NUMBER>}{3600} \\approx 4.693^{\\circ}$\nNow, to convert from spherical to rectangular coordinates, we have to define which of RA, DEC, and R can be assigned to $r$, $\\theta$, and $\\phi$.", "371" ], [ "R should be $r$ - that's pretty straightforward. Since RA can be thought of as \"celestial longitude\", we'll assign it to $\\theta$, and thus declination will be $\\phi$.\nTo clarify, I'm defining $\\phi$ as the angle from the xy-plane - so a $\\phi$ of $\\dfrac{\\pi}{2}$ would mean pointing straight upwards. I know some sources define $\\phi$ as the angle complementary to that angle (so, $\\dfrac{\\pi}{2}$ - the angle from the xy-plane), but for astronomical purposes, I think the definition I'm using is more intuitive and easier to work with.\nWe can then use the conversions:\n$x = r\\cos{\\theta}\\cos{\\phi}$\n$y = r\\sin{\\theta}\\cos{\\phi}$\n$z = r\\sin{\\phi}$\nSo, for Alpha Centauri AB:\n$x = 4.37 \\cos{219.902^{\\circ}} \\cos{−60.833^{\\circ}} \\approx -1.634\\: \\rm{ly}$\n$y = 4.37 \\sin{219.902^{\\circ}} \\cos{−60.833^{\\circ}} \\approx -1.366\\: \\rm{ly}$\n$z = 4.37 \\sin{−60.833^{\\circ}} \\approx -3.816\\: \\rm{ly}$\nand for Barnard's Star:\n$x = 5.958 \\cos{269.452^{\\circ}} \\cos{4.693^{\\circ}} \\approx -0.057\\: \\rm{ly}$\n$y = 5.958 \\sin{269.", "371" ], [ "What is the math that we use to calculate the radial velocity?\nWith the usual nomenclature:\n$G$ = universal gravitational constant\n$M$ = mass of primary\n$m$ = mass of secondary\n$a$ = semi-major axis of the elliptical orbit\n$e$ = eccentricity of the elliptical orbit\n$\\theta$ = true anomaly\n$r$ = radius vector (position vector from de focus)\nThe mathematical expression to calculate the radial velocity is:\n$$v_r=\\sqrt{\\frac{G (M+m)}{a(1-e^2)}} \\ \\ e \\sin \\theta$$\nAnd the expression for the velocity component perpendicular to the radius vector is:\n$$v_{\\theta}=\\sqrt{\\frac{G (M+m)}{a(1-e^2)}} \\ \\ (1+e \\cos \\theta)$$\nNaturally, it follows that:\n$$v=\\sqrt{v_r^2+v_{\\theta}^2}$$\nThat operating can be converted into the familiar expression:\n$$v=\\sqrt{2 G (M+m)\\left ( \\frac 1 r - \\frac 1{2a} \\right )}$$\n$$v=\\sqrt{2 \\mu \\left ( \\frac 1 r - \\frac 1{2a} \\right )}$$\nWhere $\\mu=G(M+m)$ is the gravitational parameter.\nThe mathematics required to detect the maxima and minima of a function consists of calculating the places where the derivative of the function is zero.\nThe derivative of the radial velocity with respect to the true anomaly is:\n$$\\frac{dv_r}{d\\theta}=\\sqrt{\\frac{G (M+m)}{a(1-e^2)}} \\ \\ e \\cos \\theta=0 \\rightarrow \\cos \\theta =0$$\n$$\\displaystyle \\theta=\\frac{\\pi}2 \\qquad or \\qquad \\theta=\\frac{3\\pi}2$$\nWhich corresponds to the two \"semilatus rectus\".\n$\\theta=0 \\longrightarrow v_r=0$\n$0<\\theta <\\dfrac{\\pi}2 \\longrightarrow v_r>0$ increasing positive value\n$\\theta=\\dfrac{\\pi}2$ maximum positive value of $v_r$\n$\\dfrac{\\pi}2 <\\theta < \\pi \\longrightarrow v_r>0$ decreasing positive value\n$\\theta=\\pi \\longrightarrow v_r=0$\n$\\pi<\\theta <\\dfrac{3\\pi}2 \\longrightarrow v_r<0$ increasing module of negative value\n$\\theta=\\dfrac{3\\pi}2$ maximum module of the negative value of $v_r$\n$\\dfrac{3\\pi}2<\\theta < 2\\pi \\longrightarrow v_r<0$ dencreasing module of negative value\n$\\theta=2\\pi \\longrightarrow v_r=0$ And we have made a complete turn\nI attach, as an example, a table with the radial velocity, the perpendicular velocity and the total velocity (metres per second) of the Earth in its elliptical orbit around the Sun, as a function of the true anomaly (radians)\nBest regards", "521" ] ]

[ 335, 4381, 4206, 10032, 2109, 11189, 8950, 2158, 9230, 747, 5729, 2681, 6384, 4049, 4449, 3491, 1576, 3256, 4964, 10497, 7021, 9490, 171, 2967, 4540, 2798, 5553, 4808, 11356, 2893, 11065, 10198, 2357, 11325, 9236, 460, 11173, 2600, 8811, 3906, 9943, 4489, 9990, 5731, 5432, 7335, 9292, 4625, 8740, 10150, 2141, 199, 4761, 4697, 7228, 4977, 259, 7815, 8358, 498, 5239, 469, 4321, 8517, 104, 8644, 719, 8802, 7136, 1028 ]

[ [ "I found a paper(1) about the 'tail in the mouth' behaviour in the whiptail lizard, Cnemidophorus ocellifer:\nEvery time that the female moved, the male followed her. During these periods, he often maintained physical contact, covering her hind legs and base of tail region . The male also performed a series of tongue-flicks on the female's back during this activity. During the observation, the female twice executed a sequence of two or three sinuous, figure-eight movements, which were confined to a small area, and after which, the female moved away. After each movement, the male remained motionless for a few moments and then resumed following her while foraging. After 45 minutes and nearly 15 m from their initial positions, the pair entered in dense underbrush, where we could not continue to observe them.", "524" ], [ "While we observed the pair, there was no agonistic encounter between the accompanying male and other males for access or copula with the female.\nThe paper continues to explain this behaviour as simply a mating strategy:\nTwo conditional mating strategies have been described for teiid males (<PERSON>-<PERSON> & <PERSON> 2007). 1) In consensual copulations, the male courts the female, slowly circling her for several minutes, then straddling her and copulating; this strategy is often performed by a male companion, and thus is linked to accompaniment. 2) Opportunistic copulations are not preceded by courtship, and are characterized by a male chasing and holding a foraging female, and not accompanying her after copulation (<PERSON>-<PERSON> & <PERSON> 2007).\nThe 'taping the surface they are on' seems like an attempt to induce vibrations, which is a method of communication.(2)\nSome chameleon species communicate with one another by vibrating the substrate that they are standing on, such as a tree branch or leaf. Animals that use vibrational communication exhibit unique adaptations in morphology (i.e., body form) that enable them to detect vibration and use it in communication. These include unique adaptations in ear and jaw morphology that give the animal direct contact with the surface they are standing on, and enable them to detect subtle vibrations. Lizards that live on substrates that can be easily moved (such as thin tree branches or leaves) are probably more likely to use vibrational communication than lizards that live on substrates that do not transmit vibrations as easily, such as the ground or thick tree trunks.\n1- https://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032011000400031#:~:text=The%20most%20commonly%20reported%20mating,Bull%202000%2C%20Ribeiro%20et%20al.\n2- https://en.wikipedia.org/wiki/Lizard_communication", "524" ], [ "When you say 'humans can not smell when they have water trapped in their noses', I believe you mean the loss of the sense of scent caused due to nasal congestion, which is due to inflammation, blocking the scent receptors in the nasal cavity (any mechanical blockage preventing odours from reaching the olfactory nerves can cause a loss of sense of smell. This blockage can be due to inflammatory processes like simple infections causing mucus plugs or nasal polyps(1)). Since the basic structure of the respiratory tract is similar in mammals, mucous plugs reduce scent sensitivity in elephants as well.\nOlfaction occurs when odourants bind to specific sites on olfactory receptors located in the nasal cavity. They get into the nasal cavity when you breathe or sniff the air.\nMolecules of odourants passing through the superior nasal concha of the nasal passages dissolve in the mucus that lines the superior portion of the cavity and are detected by olfactory receptors on the dendrites of the olfactory sensory neurons.", "978" ], [ "This mucus acts as a solvent for odour molecules, flows constantly, and is replaced approximately every ten minutes. ...(2)\n(Thanks to @Adhish for the above point.)\nIf the water itself has a scent, then, as @KaPy3141 pointed out, it can be distinguished because it is in contact with the olfactory receptors. Scent of anything else outside cannot be determined, because they do not reach the receptors.\nElephant lungs are attached directly to the diaphragm and chest wall, allowing them to create much greater \"vacuum pressure\" for sucking water through their long trunks, while drinking.(3) To open its mouth to breathe would cause the loss of the low pressure and the water column would expelled. So the water column must first be transferred to the mouth, then swallowed before breathing can recommence.(4) Thus, as far as respiration is concerned, they cannot breathe when the trunk contains a column of water, and, as a result, odourants cannot enter the nasal cavity, and elephants cannot smell in this case.\n1-https://www.ncbi.nlm.nih.gov/books/NBK482152/\n2-https://en.wikipedia.org/wiki/Olfaction\n3-https://www.elephant.se/elephant_lungs.php?open=Elephant%20anatomy\n4-https://www.quora.com/How-do-elephants-breathe-when-drinking-water", "978" ], [ "TL;DR No, it won't die. Lizards/snakes are usually immune to their own venom.\nSince I couldn't find a good answer to this recurring question on this site, I will try to summarize it here. I found more research on snakes than on lizards, but for now we will just assume that similar mechanisms can be found in lizards.\nFirst, the question is how the venom kills the prey. What does it do in the body?\nA common mechanism is a block of acetylcholine receptors at the neuromuscular junction. Simplified, these receptors activate muscle contraction upon a neuronal signal. When the receptor is blocked by the toxin, the neuronal signal cannot be transmitted to the muscle, which paralyzes the animal. Research has shown, that some snakes and lizards have evolved different acetylcholine receptors, that can still bind acetylcholine (and activate muscles), but not the toxins (source1, source2).", "671" ], [ "This makes them immune to the most common neurotoxins found in reptile venom.\nAnother mechanism is hemorrhagic activity of the toxin, which is a disruption of blood vessel integrity resulting in bleeding and death. This was linked to a proteolytic (\"destroying proteins\") function of venom compounds (source3, source4, source5). The blood serum of snakes can contain factors that block the hemorrhagic function of toxins, possibly by neutralizing the mode of action (inhibiting proteases). This could be specific antibodies/inhibitors or an adaptation of serum proteins (source6, source7, source8).\nFurther research has implicated phospholipidases (destroying phospholipids like used in cellular membranes) as the mode of action for snake venoms. Again, phospholipidase inhibitors can be found in the blood serum of the snakes themselves. There were also reports, that the expression of these inhibitors changes from younger to older snakes (source9, source10) and can be induced by venom injection (source11). It is therefore hypothesized that venomous snakes or lizards are repeatedly exposed to small amounts of their own venom, building up immunity over their life span.\nOther modes of action include myotoxicity (destroying muscles), edema-formation or blood thinning. Again, it depends on the specific mechanism and how snakes and lizards have adapted to be immune to these.\nSince similar toxins are found in several species, snakes and lizards are often not only immune to their own venom, but also to bites of other members of the same species or other related species.", "112" ], [ "As indicated by their name, fruit flies can be found on fruits, where they prefer to lay their eggs. Since the larvae feed not on the fruit itself but on microorganisms found on rotting material, they will especially target overripe fruits. Therefore fruit flies have evolved to identify and respond to odors emitted from ripe fruits. Red wine similarly emits odors that are attractive for fruit flies. Since fermentation is a form of controlled rotting (in both cases material is decomposed by microorganisms), the resulting compounds can be similar, which includes ethanol and 2-phenylethanol.\nSo, fruit flies are attracted to the smell of wine, that's why they approach the glass. Due to their small size and the surface tension, they should be able to land on water without drowning. But wine isn't water. With an ethanol concentration of 12% we see a reduction in surface tension from ~72mN/m to ~45mN/m, which is comparable to adding some detergents.\nThis explains, why the flies are not able to escape and drown after landing. I would nevertheless argue, that the selection pressure isn't strong enough for an evolutionary adaptation.", "642" ], [ "In their natural environment, they usually would not encounter large bodies of liquid which they are attracted to and which are not able to hold their weight.\nIn evolution and behavior we have to consider the entire species. While a few unlucky animals will die in wine glasses, most other flies will not. For them being attracted to the smell of overripe fruit and ethanol is an advantage. It's a cost and benefit calculation. For the species, the costs of a few individuals dying is outweighed by the enormous benefit of finding a good place to raise their offspring (laying eggs into rotting fruits). Therefore, the attraction to these smells and approach are positively selected for, even though this results in death in wine for some members of the species.\nWatching fruit flies at a trap, you see that mostly flies land on the container rather than on the liquid, indicating that they already avoid touching down on liquid. On the other hand, fruit flies don't seem to be very acrobatic, with a part of their landings being \"crash landings\". Hence, some of these flies might just accidentally end up in the liquid or by walking down to the edge of the liquid and being caught up by it when touching it. Even though I couldn't find hard data on this, \"landing on liquid reservoirs\" doesn't seem to be necessarily a strong behavior in fruit flies, that evolution could negatively select for.", "445" ], [ "As you indicate in your question, the average age of sexual maturity is probably the best way to approach this, since immaturity is usually how juveniles are defined. Age of puberty is also different in boys and girls (the same goes for many animals), and has also decreased in the 21 century. However, as an historical average for humans 15 years is probably fair, even though there is a lot of variance. That is high compared to most animals, but there are some that have similar or higher ages of maturation, e.g.:\n* Cicadas in the genus Magcicada, which can have a 17 year life cycle\n* Elephants reach sexual maturity at about an age of 8-15 years, but usually dont start to breed until they are at least 18-20 years (see e.g. elephantsforever.co.za and Association of Zoos and Aquariums). Males mature and start reproducing later than females, and in practice it is mostly older bulls that reproduce.\n* The Nile crocodile, which reach sexual maturity at at an age of 12-16 years (largely dependent of body size though).\n* Some species of Tortoise reach maturity at ages 13-16 years (e.g.", "376" ], [ "Gopherus sp, see Germano, 1994), and, again, which is largely due to body size and growth rate. Captive bred individuals can mature more quickly.\nAs you can see, there is a difference between sexual maturity and reproductive age. To actually be able to reproduce, especially in some male mammals, you often need experience and size, which means that reproduction is delayed in practice. Whether this period from sexual maturity (with respect to producing mature eggs/sperm) to reproductive age should be defined as least partially as \"adolescence\" will affect how humans compare to other animals. In my examples, I have focused on sexual maturity (which usually has less variation between individuals).\nFor other examples, you might want to look at insects other than Cicadas that have delayed larval stages. This does for many woodliving beetles, where development times can be very variable, and under poor conditions take up to 20-30 years. This is usually not the norm though.\nWhen searching for other examples, use the terms \"age of maturation, \"reproductive age\", \"sexual maturity\" etc, to focus on sexual maturation and not gestation.", "551" ], [ "Note: I did not look at your link before posting this answer. The triple helix system looks quite complicated and somewhat unlikely to involve naturally from simple chemicals.\nConsider the ABC sex determination system for diploid individuals, where A, B and C are chromosomes with a distinct form that can pair up. Each of A, B and C contains a distinctive gene that encodes for a protein necessary for viability, two of which combine to determine the sexual characteristics. Two of the same are too much, the resulting individual is not viable and culled in an embryonic stage. This naturally leads to the forms AB, AC and BC as only existing forms.\nNow suppose that the chromosomes also encodes other proteins that, apart from the sexual characteristics, also have a great impact on the morphology of the creatures.", "29" ], [ "For instance, chromosome A holds genes that induce a (far) greater size and territorial protection, while form B induces more muscles and form C promotes intelligence. This leads to:\n* AB: big, strong and dumb and quite territorial\n* AC: big, weak, smart and quite territorial\n* BC: small, strong, smart and not territorial at all\nIndividuals produce gametes of either kind without differentiation among the gametes of either chromosome type (A, B or C) or source of the individual (AB, AC or BC) and further suppose the actual reproduction is performed by pooling a bunch of gametes in an aquatic environment with sufficient nutrition, like terrestrial fish. The following options present themselves:\n* asexual reproduction, just the gametes of a single individual. 50% chance of producing what is essentially a clone\n* bisexual reproduction, the gametes of two individuals of same sex or different sex. Again 50% chance of producing offspring, half of which are essentially clones\n* trisexual reproduction, the gametes of three individuals, two out of three individuals of the same sex again gives a 50% chance of producing offspring with less likelihood of clones, three individuals of different sex gives a 66% percent chance of producing offspring with less likelihood of clones.\nAs the latter option, three different sexed individuals pooling their gametes produces more offspring with a balanced mix of sexes this is the favored option, especially if the chances of survival of an embryo or larva are quite slim, but approximately equal for all three sexes, again not unlike terrestrial fish.", "1008" ], [ "Instead of searching for an answer based on size, which habitats/climates would fit your story best? There is actually plenty of possibilities of adaptations to temperature within reptiles of the size your looking for. I will mostly look at the lower temperature border in this answer.\nHave you considered mesothermy? Mesotherms are animals who because of high metabolic rates generate enough heat to have a constant body temperature despite changing surrounding temperature. One extant example is the leatherback turtle, who has even been found within the Arctic Circle! High muscular activity, counter-current heat exchange, thick fat covering and incredibly something similar to brown fat tissue found in mammals for generating heat without shivering.\nBut even more extreme were Dinosaurs! There has been a lot of debate about the metabolism of dinosaurs and some scientists believe that some speceis were in fact warm-blooded. You can find a lot about that in this exhausting wikipedia article.", "701" ], [ "Some dinosaurs species have lived in very cold conditions and the article gives some temperatures:\nDinosaur fossils have been found in regions that were close to the poles at the relevant times, notably [...] the North Slope of Alaska [...], so polar dinosaurs and the rest of these ecosystems would have had to cope with the same extreme variation of day length through the year that occurs at similar latitudes today (up to a full day with no darkness in summer, and a full day with no sunlight in winter).\nStudies of fossilized vegetation suggest that the Alaska North Slope had a maximum temperature of 13 °C (55 °F) and a minimum temperature of 2 °C (36 °F) to 8 °C (46 °F) in the last 35 million years of the Cretaceous (slightly cooler than Portland, Oregon but slightly warmer than Calgary, Alberta).\nThe possibility of migration is disregarded:\nBut a round trip between there and Montana would probably have used more energy than a cold-blooded land vertebrate produces in a year; in other words the Alaskan dinosaurs would have to be warm-blooded, irrespective of whether they migrated or stayed for the winter.\nSo to answer your question, maybe something around 2 °C (36 °F) can be the lower limit for year round human-sized reptiles. With hibernation you can even have it colder: the farthest north extant terrestrial reptile is the Viviparous lizard although you will have size-constrains for your human-sized reptiles...\nFor the upper limit, similar approaches are possible. If you want your species to live in hot deserts, think about heat exchangers like the neural spines of Spinosaurus, bright skin colour, behaviour adaptations like night activity or borrowing/living in caves. Compare for example here.", "671" ], [ "Cause of premature death in turtle eggs\nContext\nI am a hobbyist turtle breeder and I have been keeping and breeding turtles for 15 years (I have hatched turtles in the high hundredths).\nLong story short, few years back, my friend and I acquired a group of possible heterozygous for albinism Kinosternon sp.; here you can find a simplified but representative family tree. Squares represent adult animals (blue background for males, red background for females), while hexagons are individuals whose gender is unknown. Moreover, each shape gets a color based on the genetics of the specimen: grey for possible heterozygous (50% or 67%), black and yellow for heterozygous (100%) and yellow for albino. Everything started because of M1 carrying the genes for albinism and it is a wild caught specimen from many years ago.\nThe problem\nUnfortunately, we are having issues hatching babies from this group. Many of them die at a very late stage of development, that is, turtle completely formed, small yolk sac (that would have been absorbed within one week tops). This is not always the case, however, as I have been able to hatch some without any intervention on my part. These were hatched from different females: a clutch from a female may hatch fine, while the next ones from the very same female might not, so the problem is not related to one or more individuals, but apparently every one.\nThis happens to me, but also to my friend, who is also an experienced turtle breeder and we live in two different locations. This happens with inbreeding, but also when mating unrelated pairs: e.g.: M1 or M2 with a female from a totally different genetic line. The only reliable method to increase hatching success is to frequently check the eggs by candling and crack them open when they are ready to hatch. Unfortunately, this is still a risky operation and it is sometimes difficult to estimate development stage, especially with albinos.\nIncubation\nWe incubate our eggs in an artificial incubator. We put the eggs in moist vermiculite (1:1 ratio, which is pretty standard) inside small plastic boxes with holes on each side and lid. The eggs are buried halfway.", "759" ], [ "Temperature is controlled by a proportional thermostat that ensures precise temperature control. We tried constant temperature incubation at 28 °C, but also varying temperatures between 23 °C and 27 °C to emulate daily fluctuations that would occur in nature. The incubator is \"big\" compared to the number of eggs it contains. Talking with one breeder and owner of one of the biggest turtle farm in North America, he suggested lack of oxygen might be the cause. Hence, I moved a dozen eggs with turtles almost due (within a month or two) in a heated room (ambient temperature around 26/27 °C) and placed each lid on top of the plastic container, by allowing plenty of air to flow through, but the same problem occurs. So, lack of oxygen is not the cause, or, at least it is not caused by the incubator itself. I will try and incubate eggs once laid in that room, but I fear I will most likely end up with the same result.\nHusbandry\nI keep my animals in an indoor facility separated (each specimen gets its own tank) and I periodically introduce a female in the male's tank. I do not provide UVA/UVB, but just LED lighting. I provide top quality food to my animals, for instance:\n* commercial pellets\n* offal (heart, liver, lungs etc.)\n* live preys: mealworms and earthworms\n* fresh fish\n* cuttlebone\nCauses? Solutions?\nWhat could be the cause of embryonic death at a so late stage in the incubation process? Is there anything I can do besides what I have already tried? Would a veterinarian be able to perform an autopsy on such small animals and provide valuable insights? I think I will possibly try shellless incubation like it is done with chickens to exclude lack of oxygen as the cause.\nI have tried to be as detailed as possible, but please, feel free to ask for any clarification or missing information.\nUpdate 2022/05/28\nThe issue is still there, but I am pretty confident the cause is not genetic (this also happens with other Kinosternon spp.. The interesting thing is that I have had some hatchlings able to break the egg shell on their own, only to die a few hours later, while I have been able to rescue a handful of hatchlings by opening their eggs 2/3 days before the complete yolk sac absoprtion. My guess is that these turtles are diying because they do not have enough oxygen during the very last incubation days. Those who succeed in cracking the egg, carry irreparable damage and die because of this shortly after.", "671" ] ]

[ 3255, 8573, 2921, 10794, 1444, 5808, 9143, 9575, 10459, 4966, 417, 6087, 7231, 5, 4133, 9059, 10437, 3654, 1408, 7464, 3910, 10537, 667, 10616, 1798, 1556, 9335, 6992, 7348, 3794, 8124, 2252, 6209, 938, 2217, 2546, 2584, 2013, 4079, 8309, 9245, 1114, 7134, 3115, 3572, 5223, 813, 5591, 10487, 7600, 5797, 6696, 5822, 7246, 11106, 435, 1904, 5001, 7831, 10526, 188, 10439, 11159, 3612, 9882, 2329, 5253, 7038, 2765, 3402 ]

[ [ "Rainbow Black and White Cookies\nIntroduction: Rainbow Black and White Cookies\nNew York's classic Black & White cookies get a rainbow makeover and they are SO much fun! The sweet rainbow heart design on top hints at the colorful cookie inside. And the best part - you can make them at home!!!\nFirst of all, if you aren't familiar with the iconic Black & White, it's a soft, fluffy cake-like cookie glazed with half chocolate and half vanilla icing. What could be better? You don't have to choose your favorite flavor...hello, twist cone! Something about the chocolate and vanilla flavors together make it even better than the sum of its parts. Yes, I always choose the vanilla and chocolate twist cone at soft serve ice cream shops and I love them even more with rainbow sprinkles! And so the rainbow B & W cookie idea was born...\nThis cookie has a soft, velvety texture, more like a mini cake than a cookie. I love the taste, but find the appearance a bit ordinary, so I often make them more festive by coloring the white icing - pink for Valentine's Day, green for St. Pat's Day, you get the idea. So when I started thinking of ways to up the fun factor even more, naturally making the cookie rainbow colored sprang to mind. Read on and I will show you how to do it.\nSupplies\nCookies:\n* 1 3/4 cups flour\n* 1/2 teaspoon baking powder\n* 1/4 teaspoon baking soda\n* 1/2 teaspoon salt\n* 10 tablespoons unsalted butter, room temperature\n* 1 cup sugar\n* 2 teaspoons vanilla\n* 1 large egg\n* 1/3 cup sour cream\n* gel food colors: red, orange, yellow, green, blue and violet\nChocolate Icing:\n* 4 ounces semisweet chocolate\n* 3 tablespoons unsalted butter\n* 1/2 teaspoon instant espresso powder\nVanilla Icing:\n* 1 cup powdered sugar\n* 1 tablespoon light corn syrup\n* 1 teaspoon vanilla\n* 2 tablespoons heavy whipping cream\n* gel food colors\nNote: recipe makes 10 large cookies.\nStep 1: Make the Cookie Batter\nPreheat oven to 350 degrees Fahrenheit. Line 2 cookie sheets with parchment paper.\nWhisk together the flour, baking powder, baking soda and salt in a bowl and set aside.\nBeat the butter and sugar together in a stand mixer fitted with the paddle attachment on medium speed for 3 minutes until light and fluffy. Scrape down the sides with a spatula and add the vanilla and egg. Mix until combined. Alternate adding half of the flour mixture and mix on low, then half of the sour cream, followed by the rest of flour and sour cream.\nStep 2: Color the Batter\nDivide the batter equally into 6 bowls. Add a different gel food color into each bowl and mix to get desired colors.\nStep 3: Scoop and Bake the Cookies\nWith a 1/4 cup ice cream scoop, scoop a little of each color, one at a time, to fill the scoop.", "305" ], [ "Mine made a cool rainbow design as shown! Don't worry, it will look great no matter how you scoop it, as long as the colors don't mix together too much.\nRelease the batter onto the parchment lined cookie sheet. Bake for 10 minutes. Then rotate the pan and bake for another 5-6 minutes until a toothpick comes out clean. Don't overbake.\nTransfer to a wire rack to cool.\nStep 4: Make the Icing\nFor the chocolate icing, break the semisweet chocolate into pieces and place in a microwave safe bowl. Add the butter and microwave on half power for 30 seconds. Stir the mixture and continue microwaving at 30 second increments, stirring in between, until the chocolate is almost melted. Add the instant espresso powder and stir until all the chocolate is melted and mixture is smooth.\nFor the vanilla icing, stir powdered sugar, corn syrup, vanilla and cream until combined and smooth. The mixture should be thick, about the consistency of honey.\nFor the rainbow hearts, put about a tablespoon of vanilla icing into each of 6 small bowls. Tint with gel food colors to desired colors.\nStep 5: Frost and Decorate the Cookies\nTo glaze a cookie, turn it upside down so the flat side is facing up. Spread chocolate icing over half of the cookie with a small spatula and let set. Placing the cookie in the refrigerator will help the chocolate to set faster. Repeat with all the cookies.\nNext, spread vanilla icing on the other half of the cookie.\nNow, the fun part! Immediately, while vanilla icing is still wet, add a small dot of each colored icing right on top of the vanilla icing. You can put each into a small pastry bag or cone if you like. I just released a drop of each color with a spoon, but a pastry bag would be easier to control.", "136" ], [ "Geode Sugar Cookies\nIntroduction: Geode Sugar Cookies\nI love making beautiful desserts that taste as good as they look. Geode cakes have been a popular trend for weddings and special events, so I decided to try the same concept to make cookies. These are relatively simple to make, yet stunning and sure to impress your friends. So let's get started!\nSupplies\nCookies\n* 1 cup butter, softened\n* 4 ounces cream cheese, softened\n* 1 cup sugar\n* 1 egg yolk\n* 1 teaspoon vanilla\n* 1/2 teaspoon salt\n* 2 3/4 cups flour\nIcing\n* 2 cups powdered sugar\n* 2 tablespoons light corn syrup\n* 3 - 4 tablespoons milk\n* 1 teaspoon vanilla\nDecorations\n* rock candy\n* gel food color\n* gold luster dust\nTools\n* mixing bowls\n* spatula\n* electric mixer\n* rolling pin\n* cookie sheets\n* parchment paper\n* cookie cutters\n* food safe paint brush\nNOTE: If you have a favorite sugar cookie recipe, you can use it! This recipe makes a soft cookie, but any sugar cookie will work fine. If you prefer Royal Icing, that works too!\nStep 1: Beat Butter and Cream Cheese\nIn the bowl of a stand mixer, beat butter and cream cheese until creamy, about 2 minutes on medium speed.\nStep 2: Add Sugar, Egg, Vanilla and Salt\nAdd sugar and beat until mixture is fluffy and pale in color, about 3 minutes on medium speed. Add egg, vanilla and salt and mix until combined.\nStep 3: Add Flour, Wrap and Chill\nAdd flour and mix on low until just combined. Wrap dough in plastic and chill at least 30 minutes.\nStep 4: Roll Out Dough, Cut Out Cookies and Bake\nPreheat oven to 350 degrees Fahrenheit. Roll out dough between 2 pieces of waxed or parchment paper. Cut out shapes. I used a 3 inch round cookie cutter, but you can use any shape. Place on parchment-lined baking sheet and bake for 10 - 12 minutes. Remove and cool on wire rack.", "305" ], [ "This recipe makes about 16 cookies (3 inch round).\nStep 5: Make Marbled Icing\nMix together powdered sugar, corn syrup, vanilla and 3 tablespoons of milk. Icing should have the consistency of honey. If it is too thick, add more milk.\nSeparate into individual bowls and color with food coloring. I used black and gray for these cookies. You only need a small amount of each color. Now, the fun part! drizzle a little of the colored icing on top of the bowl of white icing and stir with a toothpick to create a marbled effect.\nStep 6: Dip Cookies in Icing and Add Rock Candy\nDip the tops of the cookies in the icing and let excess drip back into the bowl. Place on wire rack and immediately sprinkle rock candy on top. Let dry completely.\nStep 7: Paint With Food Coloring and Luster Dust\nThin the food coloring with water to make a liquid. Paint the rock candy to resemble a geode. I kept the color lighter around the edges and darker in the center. Next, mix the gold luster dust with a little vodka to make a liquid. Paint it around the edge of the rock candy geode.\nThat's it! Enjoy your beautiful & delicious geode cookies!!", "122" ], [ "Lemon Pie With Meringue Roses\nIntroduction: Lemon Pie With Meringue Roses\nLooking for a fabulous Spring dessert? Try this reinvention of a classic lemon meringue pie! It's just the right combination of sweet & tart, with fresh lemons and a coconut shortbread crust. I love the combination of lemon and coconut. Add to that a wreath of delicious vanilla meringue roses and you have a real showstopper!\nI've been decorating cakes with buttercream flowers for quite awhile when it occurred to me - why should cakes have all the fun? Why not use the same techniques to level up my pie game? This lovely decor is simply meringue that has been colored, piped and baked just like French meringue cookies. Crispy on the outside and chewy and marshmallow-y on the inside. The colorful meringue wreath is then placed atop a lemon pie or tart and voila!!!\nSupplies\nCoconut Shortbread Crust:\n* 1 1/4 cups flour\n* 1/2 cup shredded sweetened coconut\n* 1/2 teaspoon salt\n* 1/2 cup butter, cut into small c\n* 1/3 cup sugar\n* 1 egg\n* 1 teaspoon vanilla\nLemon Filling:\n* 1 1/2 cup sugar\n* 1/4 cup lemon zest\n* 1/2 cup butter, room temperature\n* 2 eggs + 2 egg yolks\n* 3/4 cup lemon juice\n* 1/4 teaspoon salt\n* 1/2 cup heavy whipping cream\nMeringue Roses:\n* 4 egg whites\n* 1 cup sugar\n* 1/2 teaspoon cream of tartar\n* 1 teaspoon vanilla\n* food coloring\nStep 1: Make the Coconut Shortbread Crust\nCombine the flour, coconut, sugar and salt in a food processor and pulse to combine. Add the butter and pulse until the mixture resembles coarse crumbs, about 10 - 15 pulses. Add the egg and vanilla and pulse until the dough begins to come together, about 15 more pulses. Do not process to the point where a large ball of dough forms.\nTurn out on counter and form into a disc. Wrap in plastic and refrigerate at least 15 minutes. Note: you can make this ahead and store in refrigerator up to 3 days or freeze up to a month.\nStep 2: Roll Out and Bake Crust\nRemove dough and roll out to a 12 inch circle between 2 pieces of waxed paper. Place into a 10 inch tart pan and trim to fit. Cover with plastic wrap and put in freezer at least 15 minutes.\nPreheat oven to 350 degrees Fahrenheit. Bake for 20 - 25 minutes until crust is golden brown. Cool.\nStep 3: Make Lemon Filling\nZest and juice the lemons. Put the sugar and zest in a food processor and pulse until zest is finely minced. Cream the butter and sugar in a mixer. Add eggs one at a time and mix to combine. Add lemon juice and salt and mix. Pour the mixture into a medium saucepan and cook over medium low heat until thickened stirring constantly, about 10 minutes.", "763" ], [ "Mixture should get to about 170 degrees Fahrenheit and coat the back of a spoon when done. Remove from heat and refrigerate to cool.\nWhip the cream. Fold into lemon mixture and pour into pie crust.\nStep 4: Make the Meringue Roses\nPreheat oven to 225 degrees Fahrenheit. Draw a circle on a sheet of parchment paper as a piping guide, approximately 8 inches in diameter. Turn parchment paper upside down and place on a baking sheet.\nIn a stand mixer with whisk attachment, beat egg whites on medium speed until frothy. Add cream of tartar. Increase speed to medium high and beat until soft peaks form. Add sugar, slowly pouring about 2 tablespoons at a time, beating until sugar is dissolved and stiff peaks form. Beat in vanilla.\nSeparate into smaller bowl and color as desired. I used lavender, pink, yellow and green. Put each into a piping bag with tip. I used the Wilton 1M tip for the roses and the Wilton 68 tip for leaves.\nTo pipe a rose, begin at the center with the piping bag straight up (perpendicular to the parchment surface.) Squeeze the piping bag until the meringue begins to release like a small flower. Now move the bag around the center to make a swirl. Continue to rotate around until you get the size of rose that you like. Slowly release pressure at the end of the swirl. There are lots of videos available online that demonstrate this technique.\nContinue piping roses in different colors until you fill in the circle. Add leaves as desired. Have fun & be creative!!\nNext, bake for 1 hour. Then turn oven off and let meringues stand in for an additional hour. Do not open the oven.\nStep 5: Decorate and Enjoy!", "491" ], [ "Hand Painted Sugar Cookies\nIntroduction: Hand Painted Sugar Cookies\nDecorated sugar cookies are perfect for many occasions - holidays, weddings, showers, birthdays, etc. I have made lots, and have been up quite a few late nights finishing them because piping intricate designs with royal icing can be very time-consuming. If you want a quicker, easier alternative, try painting instead. The \"canvas\" is a cookie covered with a base coat of royal icing. The \"paint\" is edible food coloring. They look super cute and are fun to make. Even if you aren't a great artist, I'll show you how to copy and transfer designs to your cookies, which you can then paint with impressive results.\nSupplies\n* sugar cookies (For my recipe & baking instructions, see my Sugar Cookie House Mug Topper Instructable here: https://www.instructables.com/Sugar-Cookie-House-Mug-Toppers/\n* royal icing, flood consistency\n* piping bag & tip (I used the Wilton #2 round tip)\n* tissue paper\n* edible marker\n* gel food colors\n* vodka (to thin the colors)\n* food grade paint brushes (sold in hobby stores and online)\n* paint mixing tray\nStep 1: Cover the Cookies With Royal Icing\nFor the base coat, flood the cookies with royal icing. Fill a piping bag fitted with a #2 round tip with flood consistency royal icing. First outline the cookie. Then fill in the entire cookie. Use a toothpick or scriber to even out the icing and pop any bubbles. Shake or tap the cookie if necessary to get a smooth surface. Let dry completely, 4-5 hours or overnight.\nStep 2: Draw or Find Images\nWhile the icing is drying, find or draw images to transfer. You can certainly paint freehand directly on the cookies, but if aren't quite that much of an artist, you can find and transfer images to the cookies. Either sketch images or find clipart and print on paper.", "706" ], [ "Make sure that they are scaled correctly to fit on your cookies.\nNext, cut squares of tissue paper the size of your cookies. Trace the images on the tissue paper using an edible marker. Then turn tissue upside down and trace the image on the back side.\nStep 3: Transfer Images to Cookies\nMake sure royal icing on cookies is completely dried and set. Place the tissue paper with image right side up on top of cookie. Trace over the image again with the edible marker. Carefully remove the tissue paper. Design should be transferred to the cookie.\nStep 4: Paint!\nNext, mix the paint colors. In a paint tray or on a plate, mix a tiny amount of gel food coloring (I used a toothpick). A little goes a long way! Add a few drops of vodka and mix with your brush. The thinner the mix, the lighter the color will be on the cookie. Don't worry about the vodka - the alcohol will evaporate quickly off the cookie so it won't leave a taste.\nDip the brush in paint. Dab a paper towel to remove excess paint. The more you remove, the lighter the color will be on the cookie. Then brush lightly across the cookie. Try different brushstrokes until you get the effect you like.\nLet dry between colors. Once all the colors are painted, let dry and then outline the design with a black edible marker (or you can paint lines using black gel color.) Then make sure to let the cookie dry completely before stacking or bagging.\nStep 5: Share & Enjoy!", "706" ], [ "Metallic Chocolate Decorations Using Tinfoil & Gold Leaf\nIntroduction: Metallic Chocolate Decorations Using Tinfoil & Gold Leaf\nThese chocolate decorations are a real showstopper and use simple tinfoil to create the texture and edible gold leaf for a little luxury. If you are investing in gold leaf, make sure to invest in good chocolate! the shapes and variations are endless, so get creative and have some fun.\nSupplies\n* heavy duty tinfoil (you can reuse it man\n* quality chocolate of your choice\n* melting vessel and spoon\n* small saucepan or frying pan\n* small metal cookie cutters\n* edible gold leaf\n* soft paint brush\nStep 1: Create Tinfoil Texture & Temper Chocolate\n* Crumple up tinfoil, and flatten back out to leave some texture, but don't leave any really deep valleys or high peaks.\n* Temper chocolate according to chosen chocolate type.\nI used 54% dark Callebaut chocolate callets in the photos. They temper easily by microwaving a small amount for 15 second increments until just warm enough to fully melt, with lots of stirring in between. Tempering is another Instructable topic all together. I used 3 tablespoons for the decorations shown.\nStep 2: Create Chocolate Texture and Chill\n* Spread tempered chocolate onto shiny side of tinfoil and smooth. Aim for a 2-3mm layer.\n* Chill chocolate in refrigerator for a few minutes until set-up.\n* Carefully peel tinfoil back while lifting off set chocolate. Tinfoil can be reused many times.\n* Keep chocolate away from any heat sources.", "136" ], [ "I have to be careful when my dishwasher is on, because the counter above it gets warm enough to melt chooclate!\nStep 3: Cut Out Shapes\n* Place saucepan/frying pan over medium-low heat.\n* Warm a cookie cutter in the pan for 5 seconds. This should be enough time to heat the bottom enough to cut through the chocolate, but not enough to make it too hot to hold. I hold onto the cookie cutter while it is heating, so I can pull it out if the top starts to feel too hot.\n* Use cookie cutter to cut a shape out of the textured chocolate. If the chocolate is very thin, you may be able to cut out a couple shapes before the cutter cools down. With thicker chocolate, you will have to re-warm in between each cut. Make sure to wipe melted chocolate off the cutter with a cloth/paper towel before reheating, or you will chocolate on your saucepan.\nStep 4: Add Gold Leaf\n* Carefully open up your edible golf leaf near the shape you want to decorate.\n* If your sheets are small, and a similar size to your shapes, you can invert the gold leaf onto the shape and pull away the paper. If your sheets are larger, use the brush to pull a section away and place it on the chocolate shape.\n* You can use the size of the soft brush to gently push the gold leaf into the textured surface of the chocolate.\n* You can also use a squeeze bottle to gently blow air onto the gold leaf and into the textured surface.\n* Be very gentle, as the tempered chocolate is very shiny and slippery and the gold leaf doesn't like to stick to it.\n* You can use a simple syrup (equal parts sugar and water by volume) brushed on the chocolate if you want a really dense metallic finish.\n* Store your decorations in an airtight container for as long as your chocolate is good for.\n* Use on cupcakes, cakes, tarts, or whatever delicious treat you can come up with\nEnjoy !", "136" ], [ "Decorated Bluebird and Goldfinch Sugar Cookies\nIntroduction: Decorated Bluebird and Goldfinch Sugar Cookies\nCelebrate Spring (or any time) with these delicious sugar cookie birds! In this Instructable, I will show you how to make these cute bluebirds and goldfinches. The decorating possibilities are endless, so use this as inspiration and unleash your creativity to make any kind of birds you like.\nStep 1: Ingredients and Tools\nIngredients:\n* 3 cups all purpose flour\n* 1/2 teaspoon salt\n* 1 cup (2 sticks) unsalted butter\n* 1 cup granulated sugar\n* 1 large egg\n* 2 teaspoons vanilla\n* Royal Icing\nTools:\n* Bowls\n* Spatula\n* Whisk\n* Electric mixer\n* Rolling pin\n* Parchment paper\n* Cookie sheet\n* Cookie cutters\n* Piping bags and tips\nStep 2: Mix Dry Ingredients\nCombine flour and salt in a medium bowl with a whisk.\nStep 3: Cream Butter and Sugar\nCream butter and sugar in a mixer with paddle attachment until pale and fluffy, about 5 minutes on medium speed.\nStep 4: Add Egg, Vanilla and Flour\nBeat in egg and vanilla on medium speed until just combined. Add flour mixture and stir on low until combined.\nStep 5: Wrap and Chill\nTurn out on counter and form into a flattened disc about 1/2 inch thick. Wrap with plastic and refrigerate at least 30 minutes.\nStep 6: Roll Out Dough, Cut Out and Bake\nPreheat oven to 325 degrees Fahrenheit. Roll out dough between two pieces of parchment paper to a thickness of about 1/4 inch. Cut out birds. Place on cookie sheet lined with parchment paper and bake 12-14 minutes until edges begin to turn golden brown.", "305" ], [ "Remove from oven and cook completely.\nStep 7: Prepare Piping Bags and Decorate Goldfinches\nColor flood consistency Royal Icing in the colors desired. I used bright yellow and black for the goldfinches. Pipe the yellow and let dry at least an hour. Then pipe black head, tail, wings and eyes. Keep it simple or get as creative as you like!\nStep 8: Decorate Bluebirds\nTo make bluebirds, start by piping a white belly. Let dry at least an hour and then pipe the blue body and head. Let dry again for at least an hour. Then add the wing, beak and eye.\nStep 9: Share and Eat!", "706" ], [ "Matcha Green Tea Frog Marshmallows (beginner-friendly Piped Marshmallows)\nIntroduction: Matcha Green Tea Frog Marshmallows (beginner-friendly Piped Marshmallows)\nI fell down a rabbit hole of cute piped character marshmallows and wanted to make my own. While I was in awe of all the complex shapes people could create, I wanted to make a design that was more beginner-friendly and forgiving.\nWhile I think I focus more on the decoration, I will include the recipe I used, which is adapted from:\n* this video by <PERSON> this video by <PERSON>\n* this recipe for regular marshmallows by KawaiiSweetWorld\nI also recommend this recipe from The Flavor Bender for a lot of information on troubleshooting homemade marshmallows.\nSupplies\nEquipment:\n* 2-3 piping bags\n* sifter (to dust powdered sugar and cornstarch)\n* saucepan and stove\n* hand mixer or stand mixer\n* spatula\n* candy thermometer (optional)\n* tray large enough to pipe your marshmallows on\n* toothpicks\nFor the marshmallows:\nMeringue:\n* 1 egg white\n* 1 tablespoon grams of sugar\nGelatin:\n* 1/2 tablespoon of gelatin (around half a packet)\n* 2 tablespoons of water\nSugar Syrup:\n* 1/2 tablespoon of gelatin (around half a packet)\n* 2 tablespoons of granulated sugar\n* 2 teaspoons water\n* 1/2 tablespoons of corn syrup\nAdditionally, you will need:\n* a 50/50 mix of cornstarch and powdered sugar to coat the marshmallows (I used around 1/4 cup of each)\n* 1 tablespoon of matcha powder\n* Green food coloring (optional)\n* Pink food coloring (optional)\nFor the decorations:\n* chocolate\n* small, round white (or light-colored) sprinkles\nStep 1: Prepare the Tray\nSift a generous coating of the powdered sugar and cornstarch mix onto your tray.\nStep 2: Bloom the Gelatin\nCombine the 1/2 tablespoon of gelatin (around half a packet) with the 2 tablespoons of water, and set aside.\nStep 3: Prepare Your Piping Bags\nPrepare at least one large piping bag for the main frog shape and one small piping bag for the eyes. Optionally, prepare an additional small piping bag if you want to add pink cheeks.\nI did not want to use as many plastic piping bags for such a small amount of marshmallow, so I created my own by folding parchment paper into cone shapes and taping them.\nAlternatively, you can use two round piping tips (one large and one small) and a coupler for the green marshmallows, and switch the tip between piping the body and the details.\nStep 4: Meringue\nWhip the egg white until it reaches a foamy consistency. Gradually add the granulated sugar (1/2 a tablespoon at a time) and continue to whisk until it reaches stiff peaks.\nStep 5: Create the Sugar Syrup\nAdd the 2 tablespoons of granulated sugar, 2 teaspoons water, and 1/2 tablespoons of corn syrup to a saucepan. Heat on medium heat until it reaches a rolling boil, and let it boil for 1 minute.\nIf you have a candy thermometer, you would want to cook this until the mixture reaches 230°F or 110°C\nStep 6: Mix the Marshmallow Batter\nAllow the sugar syrup to cool down a bit and slowly drizzle this mixture into the meringue, continuing to whisk.\nMelt the bloomed gelatin, and add this to the syrup and meringue mixture.", "305" ], [ "Whisk until it is just incorporated, but be careful to not overmix it or the marshmallow to begin to set. It should still have a runny consistency.\nYou will want to do the next few steps quickly as the marshmallow will begin to set rapidly.\nStep 7: Dying the Marshmallow\nIf you are adding pink cheeks to your marshmallow, set aside some of the marshmallow in a small bowl.\nAdd your matchapowder, and mix it in with a spatula. If it looks too pale, add a drop of green food coloring.\nAdd most of the green marshmallow to the large piping bag (for the body). Add the remaining to the smaller piping bag (enough for the eye details).\nIf you plan on switching the piping tips to create the body and details instead of using two separate bags, use the larger piping tip on the piping bag first and switch it to the smaller tip when you are piping the details.\nStep 8: Dying the Marshmallow Pink (optional)\nRepeat the steps with the remaining white marshmallow, this time dying it with pink food coloring. Add this to a small piping bag.", "706" ], [ "Vegan Teabag Sugar Cookies\nIntroduction: Vegan Teabag Sugar Cookies\nThese soft and sweet sugar cookies are dipped in a thin chocolate icing and shaped like cute little teabags.\nThey're the perfect treat for Christmas parties or Mother's Day celebrations and go well with a nice cuppa black tea. They also happen to be vegan. But if you aren't vegan, feel free to use regular butter or margarine and milk for the recipe. Eggs are not needed regardless.\nSupplies\nIngredients:\nCookies\n* 1 1/4 cup flour\n* 1 tbsp cornstarch\n* 1/4 tsp salt\n* 1/4 tsp baking powder\n* 1/2 cup vegan butter/margarine/butter\n* 1/2 cup sugar\n* 1 tsp vanilla extract\n* 1/8 cup plant-based milk\nIcing\n* 1 1/2 cups powdered sugar\n* 2 tbsp cocoa powder\n* 1 tsp vanilla extract\n* 2 tbsp plant-based milk/water\nSupplies:\n* Straw\n* Teabag cookie-cutter/aluminum foil\n* Plastic wrap\n* Twine\n* Scissors\n* Washi tape\nStep 1: Mix the Cookie Dough\nIn a mixing bowl, mix the flour, cornstarch, baking powder, and salt. Set aside.\nIn a separate bowl, use electric beaters to cream together the vegan butter and sugar until it becomes light and fluffy, for at least a couple of minutes. Then add the vanilla extract and plant-based milk.\nSlowly mix in the flour mixture until it's all combined. Pat into a large disk, place in some plastic wrap, and refrigerate for a few hours.\nStep 2: Cut Out the Shapes\nPreheat your oven to 350 degrees.\nRoll out the chilled cookie dough with a rolling pin, about 3/8-inch thick. Use a cookie cutter (or make one out of aluminum foil!) to cut out the teabag shapes.", "305" ], [ "Cut out a circle near the top with a straw.\nPlace the cut-out shapes on a baking sheet (greased or lined with parchment paper). Bake for 8-10 minutes, or a couple of minutes longer if you like a crispier cookie.\nStep 3: Make the Ties\nCut 12 (or however many cookies you are making) pieces of twine/string to about 12\" long. Cut a piece of washi tape to about 2.5 inches long (just eyeball it). Fold the twine in half and cover the ends with the piece of washi tape.\nThen do it again 11 more times.\nStep 4: Frost the Cookies\nOnce the cookies are done baking, let them cool. While they're cooling, you can make the icing.\nMix the powdered sugar and the cocoa powder, then add in the vanilla extract. Then add the plant-based milk a little at a time until the icing is the consistency you want.\nOnce the cookies are cooled, dip them into the icing and lay them on a plate to let the icing harden.\nStep 5: Finished!\nAll that's left to do is add the teabag tags. Just thread the string through the hole, put the washi-tape end through the loop, and carefully pull to tighten.\nThese would be cute served in a teabox and/or with tea. Just remember to not eat the string. :)\nPlease consider voting for me in the Cookies Speed Challenge!", "567" ] ]

[ 2077, 9767, 3690, 765, 5877, 9077, 1439, 10014, 6239, 703, 10, 4436, 2514, 7534, 3772, 9281, 589, 10631, 9596, 11360, 3737, 6011, 7888, 5658, 6483, 3381, 365, 2856, 10839, 2964, 7205, 5836, 8575, 9912, 3375, 9823, 2759, 4810, 5996, 6847, 5228, 1911, 2282, 2611, 226, 11318, 10308, 521, 11218, 4258, 8799, 11108, 8754, 8865, 1123, 4732, 6066, 10581, 4333, 10956, 4663, 5172, 9439, 5369, 8195, 9874, 3365, 9770, 10137, 5120 ]

[ [ "Regarding the coordination isomerism question, the reason why it's not considered as an isomer in the case of two uncharged complexes, is that there is no ionic attraction. The two coordination spheres should act as individual ions and hence participate in the ionic sphere. But in this case, where the two spheres carry no charge, there isn't a force, namely the electrostatic force, which binds the two spheres.\nYour question on CrCl3.6H2O is a very debatable topic and there hasnt been a unanimous decision that has been put forth by all the authors. Some say there are 3 or rather most of them say 3, only one author, <PERSON> says that there are 4.\nThe reason given by the authors to support there claim of only 3 isomers is not very concrete, but it still majority of the authors believe that it is true. The H2O that exists outside the coordination sphere is the water of crystallization.", "979" ], [ "The water of crystallization is believed to be present within the voids created by an anion and a cation. Now if the isomer [CrCl3(H2O)3] 3H2O should exist then it must have these voids. But here there isn't any anion in the ionic sphere, in fact it is believed that there isn't any ionic sphere. Therefore this isomer doesn't exist and hence cannot be the 4th isomer.\nNow, it's also believed that the H2O is actually held to the central metal atom (Cr) with the help of dipole forces and that the voids are not needed. So that would mean that this exists and since it is theoretically an isomer, it should also be an isomer practically.\nThat brings us to to this very important question, what is the significance of the water in the ionic sphere? Now most books say that it's the water of crystallization of that compound. So if the water of crystallization must be present in the voids so that they can be removed by physical processes like heating, the 3H2O wont be an isomer anymore, but just another compound that exists with the same molecular formula.", "979" ], [ "For those who have never had the pleasure of personally doing this, see this video. It has been known since 1807 that dissolving sodium in liquid ammonia results in a beautiful color. It was originally thought the color was due to some familiar complex instead of a solvated electron. A similar phenomenon happens with other alkali metals in ammonia.\nResearch in the field says that it takes, at least, forty some ammonia molecules to solvate a given electron. Metstable cavities form and their stability could depend highly on electrostatic interactions to solvate our electron. Ammonia will slowly react by evolving hydrogen gas,\n$$ 2NH_3 + 2e^- \\rightarrow H_2 + 2NH_2 ^-$$\nDifferences in solvent can play a huge role in the stability of our solvated electron. An analogous decomposition occurs in water, $$ 2H_2O + 2e^- \\rightarrow H_2 + 2 HO^- $$\nFamously the latter occurs faster than the former, see here in comparison to my earlier link.", "979" ], [ "We could say that these differences in rate reflect different stabilities of our solvated electron. Although, the addition of an appropriate catalyst to our ammonia will result in rapid evolution of hydrogen.\nA more quantitative description for the difference in energies is obtained by measuring the UV-vis spectrum for a solvated electron in both water and ammonia. One will quickly notice that the band appears at higher energies in water than it does in ammonia and there are considerable differences in the band shapes (the band is wider in ammonia).\nSo Why Do They Differ\nSo here I have to make the disclaimer that no current theories quantitatively reproduce the observed phenomena, such as the absorption spectrum for a solvated electron. This question has no established/accepted answer as it is an ongoing area of research.\nThe self-ionization of water has an equilibrium constant on the order of K = $10^{-14}$ and that of ammonia is on the order of $10^{-30}$. Hydronium formation occurs in the case of water and ammonium in the case of ammonia. Hydronium has a considerably lower pKa than ammonium and so it's reasonable to see why a reaction in water would be more likely with an electron. (Ammonia rarely produces a weakly acidic species, but water often produces a strongly acidic complex.)\nA slightly deeper reason may be that water forms more ordered local domains/structures in solution than ammonia and this influences the rate by resulting in a larger entropy of activation when the hydrolyzed electron breaks up these larger structures, recall that $k \\propto \\exp (\\Delta S ^\\ddagger /R) $.\nJust speculation though.", "979" ], [ "For the first example, I definitely wouldn't want to react $\\ce{CuCl2}$ with $\\ce{HCl}$, because then I would end up getting the same products again. I'm primarily driven by the motive to create something new, albeit the reaction must be a feasible one. Many factors influence feasibility, and you've mentioned the formation of a precipitate is one of them.\nReactions involving neutralization:\n$\\ce{HCl}$ would react with $\\ce{(NH4)2CO3}$, $\\ce{K2SO4}$ and $\\ce{Ba(NO3)2}$, as the reactions give out $\\ce{H2CO3}$, $\\ce{H2SO4}$ and $\\ce{HNO3}$ respectively which are weaker acids.\nReactions involving precipitation:\nI see a very tempting reaction here:\n$$\\ce{K2SO4 + Ba(NO3)2 -> 2KNO3 + BaSO4\\downarrow}$$\n$\\ce{BaSO4}$ is a very good precipitate, and I highly emphasize this fact. Just as a fun fact: It can be partially soluble if you try to dissolve it in boiling concentrated $\\ce{HCl}$ (or boiling concentrated $\\ce{H2SO4}$).\nOn similar grounds, $\\ce{Ba(NO3)2}$ would react with $\\ce{(NH4)2CO3}$ to give out the precipitate of $\\ce{BaCO3}$. How do I know this? Partly because of the fact that while testing for the presence of $\\ce{CO3^2-}$ ions in a laboratory we use the lime water test. Instead of using $\\ce{Ca(OH)2}$, baryta water or $\\ce{Ba(OH)2}$ is also used at times yielding strikingly similar results.\nAlso, I know this partly because $\\ce{CO3^2-}$ ion is notorious for forming precipitates. It forms a precipitate with a large number of ions, some exceptions (they're the only exceptions I know) being $\\ce{Na+, K+, Rb+, Cs+}$ and $\\ce{NH4+}$.\nHowever, what happens to the reactions like these?\n$$\\ce{(NH4)2CO3 + K2SO4 <=> K2CO3 + (NH4)2SO4}$$\nNeither of the product is a precipitate. Hey that's easy? $\\ce{K2SO4}$ is made up of $\\ce{KOH}$ and $\\ce{H2SO4}$. And look the base is the same for $\\ce{K2CO3}$, that means I've made carbonic acid from sulfuric acid and thus the reaction takes place.", "979" ], [ "Right? Wrong.\nIn your haste you forgot to take note that I could've used the same logic if I were to deal with $\\ce{(NH4)2CO3}$ and $\\ce{(NH4)2SO4}$. Wait! This reverses my previous reasoning! Yes it does. Or maybe we get a little confused.\nPerhaps these cations are spectators, shall I strip them off? Yeah, let's give it a try too. We're now (sadly) left with:\n$$\\ce{CO3^2- + SO4^2- <=> CO3^2- + SO4^2-}$$\nThat's bizarre. What's happening? Nothing. And that's what it is in its true form, the ions basically are just combining with each other, there are four ions, two cations and two anions, four possible combinations. Does that make it a reaction? Perhaps not. It's just an equilibrium, there's no going forward or backward. When we say there's a reaction taking place, we are implying that the equilibrium sways to the the product side, which apparently isn't the case here.", "979" ], [ "A slight misconception. According to http://www.chemguide.co.uk/basicorg/isomerism/geometric.html, the definition of geometrical isomers is (emphasis mine):\nThese isomers occur where you have restricted rotation somewhere in a molecule. At an introductory level in organic chemistry, examples usually just involve the carbon-carbon double bond - $\\cdots$\nSo basically classifying glucose and galactose as geometrical stereoisomers by using terms such as cis and trans is wrong in this context.\nThey're stereroisomers no doubt, but calling them diastereomers would be a better choice (i.e., try taking a mirror image of glucose and you're not going to get a structure which matches with that of galactose - this makes them non-mirror image isomers, better called as diastereomers; see also Addendum at the bottom of this answer). Terminologies such as R/S nomenclatures would be more appropriate in this case.\nAnd is it correct to say that glucose has $2^5-1=31$ cis-trans isomers?\nNope, firstly because of the usage of the word cis-trans.\nConsidering the chain structure of glucose:\nAnother thing is that when you look closely at the structure of glucose which is, you'll notice that it has only $4$ chiral carbon atoms. Chiral atoms are atoms which have four different groups/atoms attached to them.", "979" ], [ "I'm marking the chiral atoms with red stars for you:\nThe reason I've left out the lowermost $\\ce{C}$ atom is that I've two same groups (namely $\\ce{H}$). Now calculating, the number of isomers you've:\n$$2^4=16$$\nYou might want to exclude glucose itself with gives you the answer as $15$.\nConsidering the ring form:\nIf you're talking about the ring (glucapyranose structures) then it's true that $\\alpha$ and $\\beta$ forms will double the number and therefore you'll end up with $32$ isomers. Excluding glucose, again the number lessens by unit to give us the final answer as $31$\nAddendum:\nQuoting a wikipedia article (https://en.wikipedia.org/wiki/Stereoisomerism):\nDiastereomers are stereoisomers not related through a reflection operation. They are not mirror images of each other. These include meso compounds, cis–trans (E-Z) isomers, and non-enantiomeric optical isomers.\nThe case we're dealing with (in context of glucose and galactose) is of non-enantiomeric optical isomers.", "979" ], [ "Electrical forces between molecules determine the temperatures at which a substance freezes and boils; the stronger the forces, the higher the temperature. The freezing point of a substance is the temperature at which the force of attraction between its molecules becomes strong enough to overcome the energy of motion that its molecules have when the substance is in its liquid state.\nNow what makes water special is that it is a polar molecule means partially negatively charged at one end and positive at another and this polarity helps a single water molecule to form hydrogen bonds with other two water molecules. And hydrogen bonds are stronger than most of the bonds found in other chemicals. That means comparatively more energy is required to break this bond. Impurities and pressure variation changes the strength of the bonds, further affecting the freezing and the boiling point. So basically its the strength of the bonds between the molecules of a chemical that decides its boiling and freezing point.\nNow for other chemicals the strength of the bonds is increased by 1. Increase in the number of carbon atoms, 2. Increase in molecular weight, 3.", "104" ], [ "Increase in symmetry meaning decreased branching 4. and increase in relative strength of the four intermolecular forces ie: Ionic > Hydrogen bonding > dipole dipole > Van der Waals dispersion forces. The influence of each of these attractive forces will depend on the functional groups present.\n........\nImpurities fills the voids between molecules and hence make it denser... and since they possess charge so they are bonded with weak force, therefore to break these additional bonds additional energy is required hence boiling point increases... boiling point is a temperature threshold point where the surface particals attains that much upward pressure that they can overcome the atmospheric pressure and hence they leave the surface. Pure water has fixed boiling and freezing point and if this point changes during transition phase then the water surely has impurities in it.\nFor example sea water has increased boiling point at atmospheric pressure ie 100.7 degrees C due to added impurities.\n........\nSpace is extremely low pressure and extremely low temperature zone. When the astronauts take a leak while on a mission and expel the result into space, it boils violently. The vapor then passes immediately into the solid state (a process known as desublimation), and you end up with a cloud of very fine crystals of frozen urine.\nBut when that water boils, remember how much more volume gas takes up than liquid, and how much farther apart the molecules get. This means that immediately after the water boils, this water vapor — now at effectively zero pressure — can cool very rapidly!\nThe quick reduction in pressure (going from having water on top of it to just air) will cause a rapid boil, and then the quick action of the extremely cold air on the water vapor will cause the formation of frozen crystals: snow!", "815" ], [ "In this case, we've to calculate the oxidation states of carbon in the reactant and product side separately, the difference between those two and finally multiply it with the number of carbon atoms. While this is may be a seemlingly simple calculation, things can get uber-tricky because of the mammoth number of exceptional cases. Let's start with the basics; here's a gift for you:\n$${\\begin{array}{|l|c|} \\hline \\pu{Element} & \\pu{Oxidation Number} & \\pu{Remarks} \\\\hline \\pu{Alkali Metals} & \\pu{+1} & \\pu{Always} \\ \\pu{Alkali Earth Metals} & \\pu{+2} & \\pu{Always} \\ \\pu{Flourine} & \\pu{-1} & \\pu{Always} \\ \\pu{Halogen Family} & \\pu{-1} & \\pu{Generally} \\ \\pu{Oxygen Family} & \\pu{-2} & \\pu{Generally} \\ \\pu{Hydrogen} & \\pu{+1} & \\pu{Generally} \\\\hline \\end{array}}$$\nWhoa! I see three exceptional cases already (remarked \"generally\" in the table) and things haven't started yet. What's up with them?\nOxygen: Oxygen doesn't always exist as an oxide ion $(\\ce{O^2-})$ in its compounds, it can often-times exist as\n* Peroxide $(\\ce{O_2^2-})$: Oxidation state in this case is $-1$. Popular examples include $\\ce{H2O2}$, $\\ce{Na2O2}$, $\\ce{BaO2}$, etc.\n* Superoxide $(\\ce{O_2^-})$: Oxidation state is $-0.5$. Common examples $\\ce{KO2}$, $\\ce{RbO2}$, $\\ce{CrO2}$\n* Ozonide ($\\ce{O3-}$): $\\frac{-1}{3}$ oxidation state; for instance in $\\ce{KO3}$.\nHalogen atoms (except flourine): When $\\ce{Cl, Br or I}$ combine with elements of higher electronegativity ($\\ce{O and F}$), then these halogen atoms can show positive oxidation numbers; commonly $\\pu{+1, +3, +5, +7}$. In $\\ce{BrF5}$, that's an inter-halogen compound, $\\ce{Br}$ is in $+5$ oxidation state.\nHydrogen: In case of metal hydrides, it can show $-1$ oxidation state. As in $\\ce{NaH}$.\nPhew, er any more exceptions? You dare ask? Metals. Wait! Aren't metals electro-positive!? Yes, they are, but in some cases they can show zero or even negative oxidation numbers.", "979" ], [ "For example in $\\ce{CsAu}$, gold shows a $-1$ oxidation state. Let's bring in coordination-compounds: nickel in $\\ce{[Ni(CO)4]}$ finds itself in zero oxidation number.\nThere are plenty of them, I'm saving them for another day.\nLet's try calculating things you've asked.\nFor ethanol (\\ce{C2H6O}) we don't know the oxidation state of the carbon atom. Why don't we assume it to be $x$. Now, the oxidation state of a compound is either zero (if it's a neutral species) or it's equal to the charge it bears. Is ethanol neutral? Yes it is. So the individual oxidation numbers of elements (times the number of elements bearing that oxidation state) should sum up to be zero.\n$$2x+6(+1)+1(-2)=0$$\nSolving, we get $x=-2$. Doing the same thing for carbon-dioxide, we can get $x=+4$. So a carbon atom changed its oxidation state from $-2$ to $+4$, that's a jump of $+6$. And how many carbon atoms were doing this? Two carbons. That gives us $n=12$.", "979" ], [ "Should I relate the number of moles between substances when converting weight units?\nGood day! I graduated from an undergrad degree of chemistry almost 3 years ago but I'm frustrated that I fail to reconcile these things:\nIn gravimetric analysis, to get the correct amount for the desired way of expressing the analysis result, we convert the mass of the acquired substance to the desired form, and in doing this, we should relate the number of moles of the acquired substance to the desired substance. For example, if you desire to get the grams $Al$ from a sample which you assayed gravimetrically until you have formed $Al_2O_3$, then you have to use the following formula:\n$\\text{grams } Al = \\text{grams } Al_2O_3 \\times \\frac{2\\times MW Al}{MW Al_2O_3}$\nwherein the factor $2$ in the numerator was obtained from the term $\\left( \\frac{4 \\text{ mol } Al}{2 \\text{ mol } Al_2O_3} \\right)$, which arose from the oxidation reaction $4Al + 3O_2 \\rightarrow 2Al_2O_3 $.\nNow, the question is, should I also use this method of conversion if I just want to express %Al from a %$Al_2O_3$ concentration of a certain substance, even if I don't plan to do a gravimetric analysis to find it? Also, this method of conversion is reaction-specific, but there could be many different ways, not only single-step chemical equations but also multiple-step ones in which the overall mole relation of the substances in a given chemical equation is different from that of a different chemical equation.\nAlso, what about the expression of ppm $N$ from ppm $NO_3$ and ppm $NO_2$? Does their conversion method work in the same way in which you have to know the reaction involving $N$, $NO_3$ and $NO_2$ to know their mole relations, knowing that monatomic $N$ is not very easy to generate? In this case, I can only see that the conversion method is based on the number of atoms the primary element in each form not on a certain reaction like thee previous case.", "565" ], [ "But if that's the case, then I have another contradicting case to show:\nAnother one is that of between $NaOCl$ and $Cl_2$ in disinfection solution formulations. If you base it on the last method I mentioned, then the mole ratio should be 2 mol $NaOCl$:1 mol $Cl_2$ because you only have one $Cl$ atom in $NaOCl$ while $Cl_2$ has 2, but according to all of the reputable resources I have found in the internet, the mole ratio here is 1:1. The reason here is supposed to be because of the chemical equation $Cl_2 + 2NaOH \\rightarrow NaOCl + NaCl + H_2O$.\nIf the answer is supposed to be obvious after all these, or I am just completely missing the point, I hope you would be kind to point it out clearly because it's really bogging me down.", "870" ], [ "A primary standard is critical for an analytical result. If we dissolve a known mass of a material into a known volume, we must be able to know its concentration with confidence. Such a standard must be easily made very pure (> 99.95%), it should not decompose, and it must be fairly robust to say heating or vacuum. We use such standard solutions as, for example, titrants. This is surprisingly hard to come by, and so we say that secondary standards are materials that do not meet these strict criteria.\nSay you want to titrate a sulfuric acid solution for quantitative work, you could use a known concentration of NaOH or KOH and volumetrically determine the concentration of the sulfuric acid solution. In fact, dissolving pellets of these particular bases in a known volume of water is not sufficient to calculate concentration with any confidence in analytical work because the solids are contaminated with carbonate from atmospheric CO$_2$.", "979" ], [ "In general these carbonates contaminate alkaline solutions quite readily through this reaction: $\\ce{OH- + CO2 -> HCO3-}.$ This is why we would have to titrate the concentration of $\\ce{NaOH} $ solution with a primary standard before using it as a secondary standard.\nNow there are acid and base primary standards available, so why would one ever need to use a secondary standard? Usually it’s a matter of specific needs and convenience. Whenever possible, use a primary standard if your results actually matter.\nLet us look at a specific case where a secondary standard is useful: potassium permanganate is exceptionally useful as a titrant because it serves as its own indicator where the presence of a purple color signifies the end point, but it is unstable in light or heat due to this reaction: $\\ce{4 MnO4^- +2H2O -> 4MnO2 + 3O2 + 4OH-}$. This is why solutions of it must be stored in a dark cool place; even still, we must standardize the concentration of such a solution and we can only trust its measured concentration for a short time thereafter.\nA secondary standard solution of $\\ce{KMnO4}$ is usually titrated by oxalic acid, a primary standard, and then used to determine the concentration of a number of other analytes.\nThe reaction with oxalic acid can be summarized as $\\ce{5 H2C2O4 + 2 MnO4- + 6H+ -> 10CO2 + 2 Mn^{2+} + 8H2O}$ where everything except $\\ce{MnO4-}$ is colorless. The end point of this titration is a marked by a purple color due to unconsumed $\\ce{MnO4-}$. This allows you to make a standardized solution of potassium permanganate that can be used for a short while.\nNow, how would we use this? Solutions containing $\\ce{Ca^2+, Pb^2+, Ag+, Mg^2+, Co^2+, Zn^2+}$ and etc. can be precipitated as a metal oxalate. You would then digest this ppt in an acidic solution and titrate the released $\\ce{H2C2O4}$, where the end point is marked by a purple color, allowing you to infer the original concentration of the metal ion in the original solution.\n$\\ce{KMnO4}$ was used in mineralogical surveys of uranium prior to the Manhattan project, where better techniques were developed to quantitate.", "979" ] ]

[ 1213, 10091, 5390, 11232, 933, 3232, 7926, 6739, 643, 3018, 8464, 10188, 10184, 5900, 6980, 6189, 7535, 9715, 8217, 2907, 8845, 1731, 9392, 4722, 10291, 6229, 9493, 3896, 8630, 10445, 9926, 214, 6616, 6015, 4472, 1347, 4358, 5957, 2668, 10828, 2464, 10490, 7600, 9487, 11312, 4217, 6034, 46, 6334, 10794, 5943, 6267, 7334, 6886, 9232, 3230, 3770, 10252, 1146, 9385, 3097, 2062, 605, 2092, 2283, 4823, 7323, 2748, 10278, 692 ]

[ [ "Ideas like differentiation could help show how electricity and magnetism are related. In fact, physicists actually look at them as a single force called electromagnetism. But, it is important to note that a magnet not moving or changing relative to an electron will not put any force on the electron. Said another way: an unchanging magnetic field will not create or change an electric field. The reverse is also true: an unchanging electric field will not create or change a magnetic field. This change is required both ways at the same time.\nYour point is a critical idea in physics, a self sustaining electromagnetic field due to constant change. The idea is explained in <PERSON>'s equations. The idea is used as the explanation of light, also known as electromagnetic radiation. The idea is also used in the explanation of the earths magnetic field.", "395" ], [ "And in the explanation of the newly developing model of a Polariton. And most likely in many more areas of science.\nIf you want to know more about electromagnetism, and you already know how differentiation and force fields work, I would recommend starting with <PERSON>'s equations, then move into understanding Polarization.\nEDIT:\nIt appears people may be upset about the lack or presence of causality in my answer (a comment after a down vote would be nice)... I would like to address this point, and the comment provided, but it has no simple answer.\nIf I use a magnet in a generator to make electricity the cause is clear. But, then I can use that same motor to do the opposite, generating motion (a changing magnetic field) from electricity. Clearly one is not the cause of the other.\nA case for causality could certainly be made for earth's magnetic field and core current... but which one actually did come first the chicken or the egg. Not sure geologists have enough evidence to prove a changing magnetic or changing electric field came first, just knowledge that our magnetic poles swap.\nFrom the case of earth it is clear the question is not easily answerable. In quantum physics the electric field of an electron must have an angular momentum to give it the magnetic field measured in experiments. However, it does not actually spin.\nEDIT 2:\nThe electric and magnetic fields themselves do not experience the concept we know as causality, only the transfer of momentum using the electromagnetic force is a result of causality.", "780" ], [ "The science starts to fail at point 3 and 4 depending on your interpretation.\nPoint 3 says that mass converts to energy and vice versa, this of course is true. Combined with point 4 it however suggests that this can happen arbitrarily, this is where the physics fail, most notably the conservation of momentum. Bad practice, certainly for science-based, but here is the wiki quotation:\nBecause of momentum conservation laws, the creation of a pair of fermions (matter particles) out of a single photon cannot occur. However, matter creation is allowed by these laws when in the presence of another particle (another boson, or even a fermion) which can share the primary photon's momentum. Thus, matter can be created out of two photons.\nSo unless you can shoot one pattern of very high energy photons from one side and a second set from the other you can't do this.\nAnother physics law you are breaking is Heisenberg. You can either know the exact location of a particle or the exact speed. Not both simultaneously. To create matter in a specific configuration at an atomic level you need to know the exact location of the colliding photon.", "343" ], [ "Since you know the velocity of the photon you would be in breach of the uncertainty principle of Heisenberg.\nTwo more points I would be highly doubtful about, but can't give you concrete evidence for, is whether you can possibly create a (stable) photon pair with a high enough energy to create neutrons and protons. Also at very high energy densities the non-linear regime of electro-magnetic waves will probably become annoying.\nLastely point two might not strictly speaking be true. Some loop holes in quantum entanglement theory might allow for FTL communication (see comment) but as far as I know there is no major consensus about the loop holes in quantum entanglement. To give a gist of it, quantum entanglement is instantaneously (experimentally proven <PERSON>, et. al., Nature). So if you take a pair of particles, quantum entangle them, move one particle to the other side of the universe as soon as the quantum entanglement is broken you will know it instantly on both sides of the universe. If you could do this with enough mass kept in a quantum entangled state you could send messages instantaneously. Of course you should send the mass there in the old fashioned way. Saw this method once already used in a science fiction novel very nicely.", "795" ], [ "Note: Was going to comment on <PERSON> answer, but Without the 50 reputation yet, I'd like to build off their example of living organisms being a local system with a decrease in entropy, and how this is balanced out.\nAs <PERSON> pointed out about living organisms:\nBut although they can reduce entropy locally, they must increase the entropy of their surroundings by at least as much in the process.\nThis is the crux of your answer. Although a local reduction of entropy does not increase the entropy of it's surroundings, but rather the constant reduction of entropy in the surroundings enable these local low entropy states to exist in order to approach equilibrium. It is crucial distinction to make, between a region of lower relative energy vs. a region who's entropy is constantly being reduced.\nThe solar system is a great example for visualization purposes, although it is itself a subsystem of a larger system, ad infinitum.\nIn order for any life on Earth to exist in a manner that reduces entropy; so much so that 7+ billion humans can exist, build cities that remain rigid, and coexist with trillions of other organisms, somewhere outside of the system there must be a region of spacetime with a very high entropy interacting with this system.", "943" ], [ "The sun, a region of very high energy, directly interacts with the Earth. There are no true closed systems.\nAside\nI am currently working on a personal theory (inspired by the work of <PERSON> and <PERSON>) that the second law of thermodynamics is the most fundamentally important reason that life exists; that the formation of amino acids, and complex life is a necessary byproduct in every solar system (with the proper precursors) in order to approach equilibrium.\nAny solar system as an isolated system (each star is so far apart from the next, it's isolated enough) and entropy cannot decrease over time, even as the entropy of the star is reducing through nuclear fusion. As energy from the star is added to say, the ocean of a planet, the entropy increases locally before being dissipated through the medium. Along the way, areas of uneven energy cause molecules and atoms to organize themselves in a manner which is conducive to (a) the medium of energy, and (b) the manner in which entropy equilibrium is reached (the environment). These reorganized molecules would themselves be local areas of low entropy, further altering the manner in which entropy/energy is dissipated through the system.", "943" ], [ "It's likely bad taste to answer your own question, however, here I am only pointing out the argument of another in the literature. I also won't accept this answer to allow others to respond.\nSurprisingly, my above guess that perfect copying is only limited by the probability of spontaneous emission... might actually be correct.\nQuoting from [<PERSON>, P. W., <PERSON>, M. L. Photons cannot always be replicated. Physics Letters 92(A) no. 7, pp.", "682" ], [ "321 - 322 (1982).]:\n\"The probability of spontaneous $(n_s = 0)$ generation of signal photons is equal to the probability of stimulated generation when there is initially one signal photon already present.\"\n\"This result is traditionally expressed in the context of ordinary stimulated emission by an initially excited atom. The point here is that this fundamental law applies to all stimulated processes. Whenever there is a possibility of stimulated generation of photons, there is also the possibility of spontaneous generation. And when there is initially one signal photon, the rate of spontaneous generation is precisely equal to the rate of stimulated generation. (More generally, the rates are equal when the expectation value of the signal-mode photon number is unity.) Of course, the absolute rates are different for different purposes...\"\n\"...It should be mentioned that Wooters and Zurek [7] have independently reached a similar conclusion, that no device is able to clone with certainty photons in an arbitrary state of polarization. Their agreement is general: The linearity of quantum mechanics forbids the existence of such a device. The argument of Wooters and <PERSON> does not rule out the amplification of any given state by a device designed specifically for that state, but it does rule out the existence of a device capable of amplifying an arbitrary state. However, if one designs a device to amplify a specific state then he is assuming a priori knowledge of the state.\"\nSaid differently: the ability to achieve stimulated emission without spontaneous emission, or more generally, the existence of quantum amplifiers capable of operating below a critical noise threshold, would mean the absurdity of allowing for superluminal information transfer via a FLASH-like mechanism: http://link.springer.com/article/10.1007%2FBF00729622.\nI suppose this quote also have relevance to another question on this site: http://physics.stackexchange.com/questions/74550/why-doesnt-the-no-cloning-theorem-make-lasers-impossible\nSpecifically, we can say that any gain medium in the optical cavity of a laser will have some probability of spontaneous emission, and thus, rigging the gain medium so that the properties (or subset thereof) of this spontaneously emitted photon match that of the photon one is attempting to clone, means knowing a priori knowing the photons state vector. Therefore, \"no cloning\" does not preclude the existence of lasers or require that stimulated emission have some degree of \"sloppiness\".", "682" ], [ "How would an observer extremely close to light speed perceive (experience) the universe?\nIn the following we consider an Earth bound reference frame.\nFor an observer very close (but under) the light speed, radiation from the universe would emanate from a single point in the direction of travel, and all radiation would be Doppler shifted to gamma ray wavelengths.\nIn this direction, this link was sent to me by <PERSON> , related to another question.\nSo as the observer approaches light speed, his field of view shrinks to a point from which radiation of arbitrarily high frequency is emitted. These are consequences of aberration , beaming, and Doppler shift.\nRelated to the possibility that extremely high frequency radiation could create a black hole, check this link\nTo make my point clear (and fun), I will consider that the observer reaches a speed of\n$c$*googolplex/(googolplex+1), where $c$ is the speed of light in vacuum.\nI realise that even writing a googolplex in decimal form is physically impossible. I do not question how much energy is required, and I do not question how the observer is accelerated at this speed. There in nothing in physics that would forbid me to consider this thought experiment, in principle.\nQuestion. How would an observer in this state of motion perceive (experience) the universe?\nThe invariance principle of relativity tells me that nothing special will happen. And yet, I know that way before the speed of c* googolplex/(googolplex+1) is reached, something will happen, the observer will perceive a universe with different properties.", "275" ], [ "He will either \"see\" the universe as a black hole, naked singularity , or something else. You cannot Doppler shift the radiation coming from a point source to infinity , and pretend nothing extreme will happen. How do you solve this paradox?\nEdit. A possible connection can be made here with the Unruh effect, and the emergence of an apparent horizon for an accelerated observer (because you have to accelerate the observer, in order to get closer and closer to the speed of light). I suspect though that a full resolution of this paradox will involve quantum gravity or string theory. In any case, there is a paradox here (a contradiction with the principle of invariance in relativity), so I welcome any suggestions and comments.", "43" ], [ "The answer to this is a bit nuanced so I have now edited the answer to make it as clear as possible.\nThe big picture is: Yes, it is possible to measure a wave function, if it is possible to find or produce particles with that wave function so that repeated measurements can be made (not on the same particle each time, but on a different particle which is known to have the same wave function). This can be done in practice. For example, this experiment effectively measures the magnitude of the wave function in momentum space for an electron in a hydrogen atom: source.\nIf you write $$\\psi(\\vec{r})=A(\\vec{r})e^{i\\alpha(\\vec{r})}$$ For $A,\\alpha$ real, then $A$ can be determined by measurements of position, and I believe it is possible to find $\\alpha$ only from momentum measurements up to a constant offset $\\alpha(x) \\to \\alpha(x) + c$. Because of this constant offset which is not measurable, $\\psi(\\vec{r})$ is not measurable at a point, but $|\\psi(\\vec{r})|^2 $ is, $A(\\vec{r})$ is, and $\\alpha(\\vec{r})$ is up to that \"offset\", which is called a global phase.\nOf course, any finite number of measurements will only give information on a finite number of points of $\\psi(\\vec{r})$, each with uncertainty as well, especially because many measurements are necessary to measure a probability. These measurements must be done by repeatedly preparing a particle in that wave function and then measuring at a chosen later time. The experimentalist does not need to know what the wave function is beforehand, she/he must only know that the wave function is the same for each particle. Then, she can interpolate in between the measured points to come to a good guess for $\\psi$ at all points. In practice, any experimental outcome which is predicted by $\\psi(\\vec{r})$ can also be used to constrain it.\nThere is a practice of measuring states called Quantum Tomography. It has its own wikipedia.", "795" ], [ "It is usually used for finite-dimensional systems. But in reality every system is infinite dimensional, one only treats them as finite-dimensional. One could treat the position space wave function in the same way.\nThat being said, though it can be done in principle, I'm not aware of a full tomography which has been done in practice. If one really doesn't exist, this is a severe experimental weakness of testing the theory in my view. If anyone has a source to one, I'd be interested. I know of many momentum experiments where the fourier transform of the wave function was in fact checked, but not the entire thing.\nI will point out again for clarity, because it seems that others are of the opinion that I have not emphasized this enough, that if you do not have the ability to find or produce many particles in the unknown state $\\psi$ then it is not possible to measure in practice. It seems to me, though, that a clever setup could be used to measure almost any wave function in principle. Whether technology has reached that point is another question. But I will do due dilligence and flag that last statement as opinion, because I cannot provide references or proofs that it must be so.", "795" ], [ "Scattering, interpreted broadly is just \"probe with wave or particle\" and \"measure response\" and thus I claim that it is the principle behind most if not all experimental techniques in physics.\nMost of the scattering techniques I give below are \"just\" applications of Rayleigh scattering, but I hope you can see that the simplicity of Rayleigh scattering is precisely what makes them useful experimental tools!\nX-ray and neutron scattering experiments are used to find the structure of complicated materials, for instance. The keyword here is \"<PERSON>'s law\" in the case of crystal lattices.\nA popular technique to probe dynamics is \"Dynamic light scattering\". The principle here is that scattering can detect fluctuations due to Brownian motion in complex fluids, and this information is encoded in the autocorrelation of the measured intensity.\nWith scattering experiments, you might think you're screwed if your probe scatters multiple times before it comes back to your detector (because then how will you be able to interpret the data). However, Diffusing wave spectroscopy is a very clever technique that applies in the presence of multiple scattering events.\nThe field of acoustics is all about scattering of sound waves. In materials there's a lot of interest in studying phonons - these are also probed via scattering of various types.\nIn the generalized interpretation of scattering, conductivity / resistivity measurements in hard condensed matter also become scattering experiments.", "795" ], [ "There you probe with a electromagnetic wave by causing the voltage in a wire to your sample to oscillate, and you measure the response in the form of electron current. Examples of recently popular materials studied this way: high-temperature superconductors, integer and fractional quantum Hall devices, graphene, topological insulators, etc.\nAnd obviously, from this point of view, particle colliders and detectors do a kind of scattering experiment as well.\nThe list goes on and on. Many, if not most things studied in physics are waves of some sort, and thus scattering processes are very relevant to experiments. One prominent non-example is most of astrophysics, where we have no chance of actually probing the stars ourselves and can only observe what they do on their own. You might argue that astrophysics is therefore just \"observational\" and not \"experimental\".", "70" ], [ "I'll just go ahead and write this down even though it's already been covered in the other thread.. but I didn't post there so :)\nFirst, if you think of light as a wave (which is really a semi-classical way of thinking but might be enough to answer your question) you can invoke the Huygen-Fresnel principle which in this case boils down to considering every point on the reflecting surface as an origin of a re-emitted spherical wave with a starting phase directly related to the phase the point got from the incident wavefront.\nThe superposition of these wavefronts, after you let them destructively interfere with each other, will amount to a new combined wavefront which propagates according to <PERSON> law (angle of incidence = angle of reflectance). See this image for the corresponding illustration of refraction (which is very similar, I couldn't quickly find a good image of reflection):\nNow, light really doesn't behave \"sometimes as a particle, sometimes as a wave\". It is always detected as quanta (particles) but the probability amplitudes (phases) propagate in a wavelike fashion. One way of expressing the propagation is to say that a photon is sort of split and takes every possible path between A and B (or, in the case of a reflector, from A to any point on the reflector and then from there to point B by any means). Every path gets a phase contribution, and all the indistinguishable paths are summed.", "795" ], [ "Most paths are simply cancelling each other but some constructively interfere, creating a large contribution (in case you don't know QM, the probability amplitude squared is the probability of the described event so a large contribution means this result will most probably occur). There is a VERY good image and description of this process in <PERSON> - QED The strange theory of light and matter (as I wrote in the comment above).\nIn the case of the reflector, the large contribution occurs at the classical angle of reflectance (<PERSON>'s law again). Notice the similarity between this formulation (called the path integral approach) and the semi-classical principe outlined above, this is not a coincidence of course.\nAlso to briefly digress on your implied question on the per-atom non-zero \"reflectance\" time - saying that an electron-orbit absorbs the photon energy for a while the re-emits it a non-zero time later is of course also a slight simplification. In reality the electron interacts with the a photon, changes its momentum a bit, the re-emits (interacts) with the new photon and changes its momentum again. This scattering process occurs at all allowed momenta and intermediate times, which are then all superpositioned like above and hence I'm not sure it's meaningful to talk about any appreciable time of reflectance. Notice that this scattering is in practice very different from scattering which can excite the electron to another orbit.", "795" ] ]

[ 4429, 2925, 3012, 5947, 985, 632, 584, 1380, 9044, 8217, 2506, 551, 3901, 11081, 37, 6392, 10449, 2327, 4456, 5527, 608, 2565, 1088, 4996, 11172, 4982, 3327, 9950, 7871, 6213, 10085, 5786, 4139, 6010, 9390, 9608, 411, 7259, 2299, 8332, 10891, 1924, 4985, 4959, 6191, 1795, 6096, 1093, 2119, 6766, 821, 8028, 11315, 6931, 9838, 2142, 9675, 9704, 8701, 6211, 10427, 614, 7344, 1506, 10469, 5333, 2458, 8868, 7301, 10107 ]

[ [ "Laser Cut Treasure Chest Money Box\nIntroduction: Laser Cut Treasure Chest Money Box\nI really love the way you can get wood to bend when cut in a special way on the laser.\nI've adapted the Flexbox2 pattern generated from https://www.festi.info/boxes.py/FlexBox2 to turn it into a pirate themed money box.\nThe box is 10cm x 7cm and is 10cm high, and can be made from 1 A4 sheet of plywood\nStep 1: What You Need\nLaser cutter / engraver\nThe pattern - I have attached in ai and dxf formats\n1 sheet of A4 birchwood ply\nWide masking tape (App tape)\nWood stain for inside (Optional)\nIndoor wood varnish (Clear)\nPaint Brush\nStep 2: Mask Your Wood Sheet\nGet your A4 birchwood ply sheet and the App tape (Masking tape)\nThis tape is wide enough to mask the whole sheet, so stick some on and smooth it down.\nThis prevents smoke damage to the wood so you get a good finish.\nStep 3: Import the Pattern Into Your Laser Program\nImport the pattern into your laser program\nSelect the 3 areas for engraving (Skull, anchor and ships wheel) and set them up as engrave.\nSelect the lines for cutting and set them up for cutting.\nMake sure you engrave first and then cut.\nSettings will depend on the power of your laser.\nFor a 35W laser\nSettings are Engrave: Speed 350, Power 15 Scan Gap 0.1\nCut: Speed 6 , Power 60\nStep 4: Upload to Laser and Go\nUpload your pattern to the laser.\nInsert your masked wood sheet and pin it down with magnets, making sure the magnets are outside the lasering area.\nPress the Go button on your laser and wait for it to finish.\nStep 5: Press Out and Peel Off Masking Tape\nPress out the pieces from the sheet of wood (Most of them will fall out on their own)\nCarefully peel off all the masking tape. Take your time - it will come off!\nStep 6: Stain the Reverse Side of the Wood (optional)\nI don't like the reverse side of the wood so I stain it. I'm using a silver stain.\nYou can see the before and after pictures - so you can make up your mind whether you want to do this or not.\nStep 7: Varnish\nVarnish the outside of the box pieces with clear indoor wood varnish.\nStep 8: Assemble\nThe box is easy to assemble - it just clips together. Start with the base, then attach the sides, the back and the front.\nStep 9: Admire and Use\nAdmire your new pirates treasure chest money box and make sure you fill it with plenty of cash (dubloons and pieces of eight)", "438" ], [ "Hot Glue Mosaic Coasters (or Tiles)\nIntroduction: Hot Glue Mosaic Coasters (or Tiles)\nThese colourful Hot Glue Mosaic Coasters are fun to make. I was looking at lego art, which made me think of iron melt beads and with the hot glue contest in the back of my mind I thought of doing this.\nInstead of the cutter, jig and hole punch, you could just use a craft knife and a normal hole punch. I didn't have a hole punch of the right size, so I made one. Your punch might also get a bit gluey.\nI made the cutter jig because I wanted the slices to be consistent. I made the cutter because I found it easier to cut the glue sticks with pressure from above.\nSupplies\n7mm hot glue sticks in various colours.\nParchment paper\nClothes Iron\nA surface to iron on ( used a folded tea towel to protect the surface of my kitchen counter )\nMould release ( I used Silicone spray )\nSafety goggles\nDust mask\nGloves\nFor the mould, cutter and hole punch\n3d printer\nFilament ( I used PLA and it held up fine, but filament with a higher melting point, like PETG or ABS, would be better for the mould).\nTinkercad and a Tinkercad login.\nSmall blow torch\nCalipers or Ruler\nCutter:\nCraft knife with a long blade\nHole Punch:\n4mm Aluminium Rivet\nDremel or drill with 2mm, 2.8mm and 3mm metal drill bits.\nSandpaper\nPliers ( I used needle nose pliers and wire cutters )\nHammer\nBench vice (or another way to clamp the rivet while drilling.)\nPopsicle sticks\nStep 1: 3D Printed Parts\nI modeled the mould, hot glue cutter and hole punch in Tinkercad.\nI've included instructions for modeling the mould in Tinkercad as I thought you might want to customise it for larger grids or thicker glue sticks. I've also included all the stl files and a link to the Tinkercad file for the mould and tools. I haven't included instructions for modeling the cutter and hole punch. They are both made up of simple boxes and cilinders in Tinkercad.", "401" ], [ "I'm happy to answer any questions regarding the 3D modeling or anything else.\nStep 2: Making the Coaster Mould\nOpen Tinkercad and log in. Start a new project.\n1: Create the grid\nIn The shapes panel search for \"grid\".\nSelect a shape called \"grid of square columns\" and enter the setting as follows:\nColumns: 10\nRows: 10\nSize 7.5 ( The diameter of a glue stick + 0.5mm tolerance. )\nGap: 0.4 ( I wanted the blocks seperated by a very thin line and this is the width of my printing nozzle.)\nHeight: 3 ( This will be the thickness of the coaster. )\nThe finished grid should measure 78.6mm x 78.6mm. This will be the size of the coaster.\nFrom the basic shapes menu add box and scale it to 78.6mm x 78.6mm x 2mm.\nClick on align and align it to the top of the grid.\n2: To make the rounded corners\nFrom the basic shapes menu add a box, make it a hole and set the radius to 1.\nScale the box to 78.6mm (width )x 78.6mm (length) x 20mm (height).\nAdd another box and scale it to 80mm (width )x 80mm (length) x 10mm (height).\nSelect both boxes and click on \"align\". Center the boxes and then group them.\nMake this new object a hole.\nCentre align this object and the grid and group them.\n3: Complete the mould\nAdd a box and scale it to 83mm x 83mm x 4mm (height).\nAlign this box and the grid with the rounded corners from the previous step, so that they are centred on the x and y axis.\nAlign the grid to the top of the new box.\nMake the grid a hole.\nGroup the grid and the box\nSelect the new object. Click on export and select stl.\nI printed the coaster mould in PLA with a layer hight of 0.28 and 25% infill.\nStep 3: The Blade Grip and Cutting Guide\nDownload and print the blade grip and cutting guide stl files. I printed them in PLA with a 0.28mm layer height and 25% infill.\nBreak a section of three blades off a long craft knife blade. I put the blade in a craft knife and used pliers to break it off.", "110" ], [ "Leather Vanity / Coin Tray - Mondrian Style\nIntroduction: Leather Vanity / Coin Tray - Mondrian Style\nThis is a useful square leather tray that can be used for coins or jewellery.\nYou can decorate it any way you like but I chose to go with a style similar to the painter <PERSON>. This uses rectangular blocks of colour to make a bright cheerful piece.\nLike many leatherwork projects - the make time is in the order of a couple of hours, but elapsed time is about a day as you need to allow drying time, for the paint and the finish.\nStep 1: Gather Your Supplies\nFor this project you will need:\n1 printed pattern\nPencil\n20cm x20cm piece of veg tanned leather approx 2mm thick\nScissors - good ones that will cut leather\nLeather paints (Angelus / Lumiere or equivalent)\nPot for your water and diluted Resolene finish (Yoghurt pot or similar)\nPiece of cardboard to protect your table while painting and coating with finish.\nPermanent marker pen (Black)\nPaint brushes\n4 rivets (6mm), setting tool and hammer (or hand held riveting tool)\nChopping board or similar as a base for when you are setting your rivets if using a hammer.\nHole punch (2.5 / 3mm) - hand held or metal punch and hammer\nProtective leather finish (Resolene acrylic or similar)\nBeeswax\nWooden burnishing tool\nStep 2: Print the Paper Pattern\nPrint out the paper pattern and cut it out. When printed on A4 paper the pattern piece should be 18cm x18cm.\nStep 3: Transfer the Pattern to the Leather\nPlace the cut out pattern on the wrong side of the leather and draw round it using a pencil. Using a ruler will help keep those lines straight.\nStep 4: Cut Out the Leather\nCarefully cut out the pattern from the leather using good scissors.", "421" ], [ "Alternatively the straight edges can be cut on a cutting board using a ruler and sharp blade.\nStep 5: Mark Out Your Mondrian Style Boxes\nUsing a ruler and the thick permanent marker pen mark out a random set of boxes similar to a Mondrian painting, Just make a random set of boxes - copy my layout or design your own.\nStep 6: Paint Your Design\nProtect your work surface with a piece of cardboard before starting to paint.\nUsing leather paints - paint the \"Mondrian\" rectangles in a random selection of colours.\nColours I used are:\nAngelus - Chilli Red, Flat White, Dark blue, Pacific Blue\nLumiere - Sunset Gold\nTIP 1: Dilute the leather paint with a little water - it goes on more evenly. You may need more than one coat but the effect is better.\nTIP 2: Rinse your brushes and change your water after each colour.\nLeave the paint to dry - preferably overnight.\nStep 7: Colour Your Edges\nUsing your black marker pen colour the edges of the leather black\nStep 8: Add Protective Coating\nMix a small amount of Resolene acylic finish with water (half and half) in a pot.\nMake sure your work surface is protected with a piece of cardboard and using a broad brush paint the Resolene on the back of the tray first. This sticks down any suede bits on the back.\nNow turn over and paint the front of the tray with a very thin coat of Resolene.\nLeave to dry for at least an hour.\nThe Resolene acrylic finish provides a water resistant coating.\nTIP: Wash your brush and pot thoroughly immediately after using.\nStep 9: Wax Edges\nWax the edges of the leather using a block of beeswax then rub the edges using a wooden burnishing tool until the edges look shiny and feel smooth.\nStep 10: Bend Up Edges\nLay a ruler across the tray from notch to notch.\nCarefully bend up the edge along the ruler.\nRun your finger or the wooden burnishing tool along the back of the edge to get a nice crease.\nDo this for all 4 edges.\nStep 11: Punch First Holes for Rivets\nTest your holepunch on a scrap piece of leather to find which hole is the right size for your rivets. This will probably be 2.5mm or 3mm\nPunch a hole in each corner tab of your tray\nStep 12: Punch Matching Holes in Your Tray\nFold each corner tab round so that the top edges are parallel.\nMark with a pencil through the existing hole for where the matching hole needs to be.\nRepeat for all 4 corners.\nNow punch the matching holes using your hole punch\nStep 13: Set the Rivets\nUse a chopping board to protect your surface when setting your rivets.", "421" ], [ "Fold Out Book Dice Tower\nIntroduction: Fold Out Book Dice Tower\nA dice tower that folds into a book for storage.\nIdeally I would have used a fantasy novel to make this but I like all of my fantasy hardbacks too much to cut up.\nWhenever gluing in this project, I recommend using heavy weights to squash whatever is being glued so that paper does not warp in the gluing process.\nSupplies\n* A thick Hardback Book\n* Mod podge\n* Paint Brush\n* Greaseproof Paper\n* Craft Knife\n* Patterned paper, a Poster or Wallpaper\n* (Optional) Material to Cover Book (card, wallpaper or fabric)\n* (Optional) Acrylic Paint\nStep 1: Separate the Page Block From the Book Cover\nThis step is necessary even if you want to keep the the original cover of your book. Simply cut along the end pages connecting the page block to the cover. Be carful to not damage the text block or the cover during this process.\nStep 2: Re-cover the Book Cover (optional)\nThoroughly cover the outside of your cover with Mod podge or PVA.\nGlue the material you want to cover you book with to the outside of the cover. I used cocktail sticks to make sure the fabric was glued into the groves on the edge of the spine.\nOnce the outside is dry, wrap the material around the edge of the book and glue it down.\nI used faux leather to cover my book, this step should be skipped if you have a nice book cover.\nStep 3: Glue the Pages\nOpen the Page block to about 1/4 of the way through and slide in a sheet of baking paper to separate the two sections. The smaller section will become our Dice Tray and the larger section will become our Dice Tower. Use a paintbrush to spread Mod Podge or PVA glue along the outside edges of both sections to glue the pages together, the baking paper will stop the two sections from being glued together.", "294" ], [ "Use a pile of books or a weight on a flat board to squash the page block to stop the pages warping as the glue dries.\nStep 4: Cut the Dice Tray\nThe two sections are currently connected by the book binding. Cut a Large rectangle from the middle of the binding end of the Tray section, Keep the cut out rectangle connected to the Tower Section and cut along the binding to separate the rest of the Tray section from the Tower section. Cutting through the Page block can be done by cutting a few pages at a time with a craft knife and moving the\nTrim half a centimetre from each (non-binding) edge of the rectangle so that it can easily fit back into the hole it was cut from.\nNow cut two long rectangles along the edges of the Tray Section.\nCut Two rectangles into the Tower Section So that they line up with those in the Tray Section when the two sections are put together; the rectangles in the tower section do not need to go all the way through, just deep enough that your dice set will fit in the long rectangles when the book is closed.\nNow glue the edges of the pages in all rectangles, including the sticking out rectangle on the tower section, and press the sections individually.\nI cut the Large Rectangle to be a 120mm x 120mm square and the long rectangles to be 30mm x 120mm.\nStep 5: Cut the Tower Path\nCut a path with ledges into the back of the Tower Section. If you keep this path within the area covered by the extending rectangle to the front then you will have more room to work with.\nThis path should be large enough any of your dice can travel through the whole thing.\nThe top of the path should connect to the other side of the tower section by a horizontal tunnel.\nThe Bottom of the path should connect to the other side of the tower section by a sloped tunnel so that the dice will roll out to the front.\nBe careful to not have any horizontal or shallow areas in the path where dice can get stuck. The blue part in the picture is where i made the path too flat at the end so had to add some insulation foam to ensure dice could get down.\nNow glue the sides of the Tunnel so that the pages stick together.\nI painted the inside of my tunnel black so that the insulation foam was not visible.\nStep 6: Cut and Glue the End Pages\nCut your patterned paper to a couple of millimetres shy of your Book Cover and glue it to the inside of said cover.\nStep 7: Glue in the Tower Text Block\nGlue the Tower Section into the cover so that the Binding is flat against the middle if the cover and the face with the tower cut into is glued flat against the back cover. I recommend not gluing both faces at once so that you can rely on Gravity to help you glue flat.", "6" ], [ "Artist Stool Made From Reclaimed Materials.\nIntroduction: Artist Stool Made From Reclaimed Materials.\nI made this stool from reclaimed materials as part of an Industrial Design Project at the University of Johannesburg. The importance of the stool as a piece of furniture in the studio or workshop needs to be a form that inspires or stimulates creativity and design. The objects around us while we create have an impact on the work we produce.\nWARNING\nThis project uses dangerous tools and materials, only do what you are comfortable with and under correct supervision. Woodwork and metalwork are dangerous, wear a thick leather apron, Gloves ( When suitable), Hearing protection, a face shield AND eye protection. The aluminium casting releases many toxic fumes and may often spray molten aluminium unpredictably as the gas escapes from the mould. Make sure to wear full PPE and only 100% cotton clothing and thick closed boots.\nThis project used a wide variety of materials and tools to create. There are many alternatives available this is just what I had access to and am comfortable using.\nMaterials:\n1. Seat and legs\n2. Oregon Pine floorboards (Old pallets could also work well)\n3. Old woollen jersey for cushion Variety of foams (yoga mats, electronic packaging and upholstery foam all work well)\n4. Second-hand cork samples for padded feet\nJoint\n1. Used Aluminium Cans and broken Window frames\n2. Rebar or other metal rods\n3. 3D printing filament\n4. Lots and lots of small nuts and bolts\n5. A small Tub of vaseline\n6. Beeswax ( Can be remelted and reused afterwards)\n7. Plaster of Paris, <PERSON> and water for the lost wax mould\nOther materials\n1. 500ml cold glue\n2. 2 part epoxy ( Longer cure time means a stronger joint)\n3. Very long wood dowels and shorter ribbed dowels for joining the strips of wood together\n4. Sandpaper ( 110, 220, 400 and 600 grit )\nTools and equipment\nSeat and legs\n1. Table saw\n2. Band saw\n3. Oscillating drum sander\n4. Jig Saw\n5. Palm Sander\n6. Belt sander\n7. As many clamps as you can buy, and then some\n8. Craft knife\n9.", "787" ], [ "Ruler\n10. Measuring tape\n11. Superglue\n12. Masking tape\n13. Vernier\n14. Drill press\n15. Long 8mm drill bits\n16. Hammer\n17. Nails\nCushion\n1. Seam ripper\n2. Crochet hook\n3. Scissors\n4. Patience\n5. Time\n6. More patience\nJoint moulding\n1. 3D printer ( Local Makerspace)\n2. Stove\n3. Pot of boiling water\n4. Small oven to melt out beeswax ( Apparently you can use a regular cooking oven but I wouldn't risk it )\n5. Sand\n6. Buckets\nJoint Casting\n1. Homemade foundry ( I will eventually make another instructable)\n2. Crucible\n3. Homemade casting tools ( Long spoons, tongs etc)\nStep 1: Photos of the Stool\nStep 2: Detail Photos\nStep 3: Technical Drawings\nHere are a series of technical drawings I created from 3D models that I made in Solidworks.\nStep 4: Sourcing Materials\nStep1: Sourcing materials\nThis project was made from reclaimed materials and as such they must be found. Building sites are fantastic sources for old wood and Aluminium. Window frames are regularly thrown away when damaged and are easy to find, bring a magnet (Al is non-magnetic) to make sure you are not picking up another material. Reclaimed wood often has nails or staples in it so be very careful when cutting and working with it. Second-hand stores often sell cheap or free jerseys with holes in them which are perfect for the cushion, alternatively check in your closet and you might be in luck.\nStep 5: Aluminium Joint 3D Mould\nThe joint was first modelled in SolidWorks (3D modelling software) and using various features ( Shell, extrude and mould) I created a three-part mould. I made it so that each part is identical so it is much easier to 3D print. Using a 3D printer at my university I was able to print the parts in three different colours of PLA.\nSpray a clear coat on each mould part and add a THICK layer of Vaseline to all of the parts.\nAttach the mould together using nuts and bolts and then melt beeswax in a pot of boiling water and pour into the mould when liquid.", "220" ], [ "Leather Ivy Leaf Coin / Jewellery Tray\nIntroduction: Leather Ivy Leaf Coin / Jewellery Tray\nThis big leather coin / jewellery tray is a stylish way to keep your rings safe on your dressing table, or a great place on your hall table to dump your coins or keys. This design is a super-sized ivy leaf. Use a bit of artistic licence when dyeing and painting it.\nSupplies\nPiece of 3mm thick leather - approx 22cm square\nLeather dye (Fiebings Pro)\nLeather paints (Angelus, <PERSON>)\nLeather Finish (Resolene)\nSwivel knife\nBevelling tool\nBackground tool\nScissors\nCraft knife / clickers knife\nDomed ball or bowl\nStep 1: Pick Some Ivy Leaves\nTo make sure I got the right shape for my leaf, I went out into the garden and picked some ivy leaves to see the different shapes and colours.\nStep 2: Choose a Leaf, Scan and Super Size\nHaving chosen one of the variegated leaves, I scanned it using my computer scanner and super-sized it ready for printing. I sized it up from its natural 7cm across to approximately 21cm across. You can do the same or use the resulting scan (as pdf) attached.\nStep 3: Print Your Big Ivy Leaf Image and Cut Out\nNow print your big ivy leaf image and cut out. This is your template ready for transferring to leather.\nStep 4: Trace Your Pattern Onto the Leather\nTurn your template over (face down) and trace round it onto the back of the leather.\nStep 5: Cut Out the Leather\nUsing a combination of leather scissors, craft knife or clickers knife, cut out the pattern from the leather.\nStep 6: Wet the Leather\nGet some water in a pot and wet the top surface of the leather using a sponge. Allow the water to soak in for a minute or two.\nStep 7: Trace the Veins\nPlace your paper pattern on top of the damp leather. Using a stylus trace the veins. You will find once you remove the paper pattern you can see the marks on the leather.\nStep 8: Carve the Veins Into the Leather\nUsing a swivel knife carve the veins into the leather.", "421" ], [ "You could do this with a craft knife, but be careful that you only score the leather and don't cut all the way through.\nStep 9: Bevel the Veins\nUsing a bevelling tool, bevel the veins.\nPut the edge of the tool along the cut line and tap gently while moving the beveller along the line.\nThis will make the veins pop out.\nStep 10: Add Texture With a Background Tool\nNow using a background tool add some texture to your leaf.\nStep 11: Shape the Leather\nWet the leather leaf thoroughly - I run it under the tap for a minute.\nUsing a domed item (I have a glass ball - but a domed bowl or plastic ball will work ) press your leather leaf face down onto the ball. Keep running your hands over the leather for a minute or two until it takes shape. Pull the leaf edges up a bit to make a nice shape.\nLeave for an hour, then take off the ball - check you are happy with the curves and leave to dry completely.\nStep 12: Dye the Leather Ivy Leaf\nDye your leather ivy leaf front and back. I'm using Fiebings Pro leather dye. They do sell a green colour, but I only had yellow and blue, so I mixed them to get green.\nLeave to dry.\nStep 13: Add Pearlescent Colour (Optional)\nNow it's up to you to determine how you want to finish your ivy leaf tray. Leave it plain or jazz it up a bit with some pearlescent colour.\nI've added a pearlescent emerald colour (Jaquard Lumiere leather paint - emerald green). This has been diluted down and applied as a wash over the leaf.\nThis is optional, if you want a plainer more realistic leaf, you can jump straight onto the Painting the Veins step\nAllow to dry.\nStep 14: Paint in the Veins\nNow for painting the leaf veins. I've chosenan Angelus leather paint in Pewter. Use a fine brush and just paint the raised veins.\nAllow to dry.\nStep 15: Apply Resolene Leather Finish\nDilute a small amount of Resolene Acrylic Leather finish 50% with water.\nApply front and back to give a water resistant finish.\nAllow to dry.\nStep 16: Enjoy Your Finished Tray\nNow your ivy leaf leather tray is finished. Place it on your table and use for coins, jewellery or other bits and pieces.", "421" ], [ "Waterproof Pouch\nIntroduction: Waterproof Pouch\nThis is a simple and easy waterproof pouch that is great for make-up or toiletries.\nIt's also a great way to up-cycle and reuse plastic wrapping from packages\nStep 1: Materials\nYou will need:\n- Sewing machine\n- Pins\n- Fabric Scissors and Normal Scissors\n- Fabric\n- Plastic (I used plastic from a package, you use thicker fabric to make it sturdier)\n- Zip (length of your choice, I used a 25cm zip)\nStep 2: Measure Fabric\nUsing a ruler and pencil, measure out a rectangle (size of your choice), drawing on the fabric with a pencil or fabric chalk.\nMy rectangle was 31cm (length) by 22cm (width).\nMake sure the top is the same length of the zipper that you are going to use, with a couple of extra cm on either side.\nStep 3: Plastic\nUse the fabric pieces as templates to cut out the plastic.\nYou will need two fabric and two plastic pieces.\nStep 4: Sew the Two Sides\nPlace the fabric and the plastic on top of each other, right sides together and pin in place.\nSew around all the edges.\nDo this with both pieces.\nStep 5: Zip\nCut out two small pieces of fabric the same width of the zip.\nPin to each end of the zip.\nSew them to the zip, using a straight stitch (open the zip half way to make it easier to sew on the zipper side).\nStep 6: Pin the Pieces to the Zip\nTaking the two large rectangle pieces, fold one of the long edges over by about 1 cm (DO NOT iron as the plastic will melt)\nPlace them on either side of the zip and pin in place.\nStep 7: Zipper Foot\nChange the foot on the sewing machine, to a zipper foot (shown on the right).\nStep 8: Sew the Zip\nSew along the length of the zipper on both sides.\nSew close to the zip, however make sure it is not too close as to cover the zip\nStep 9: Sew the Pouch\nOpen the zip half way.\nFold the pouch in half with the right sides together (as shown above, the plastic should be on the outside)\nPin in place.\nReplace the zipper foot with a normal foot on the sewing machine and sew along the three edges (leaving a 1cm seam allowance).\nStep 10: Turn Inside Out\nOpen the zipper the rest of the way and turn the pouch inside out\nStep 11: Finished!\nYou now have a finished waterproof pouch!\nMake it bigger to create a waterproof swimming bag for wet towels/bathers or smaller for a small, handbag sized toiletries/makeup bag.", "455" ], [ "Easy Interchangable Fabric Dice Tray\nIntroduction: Easy Interchangable Fabric Dice Tray\nTired of your dice rolling off the table? This instructable is for an easy to make dice tray with an interchangable fabric surface so you can change the design whenever you want.\nSupplies\nTo make this project you will need:\n* A shadow box or other deep sided picture frame (I used a shadow box frame from Hobbycraft)\n* A sheet of self-adhesive felt\n* Fabric in the pattern and colour of your choice (I used swatches from Spoonflower)\n* A craft knife\nStep 1: Take Apart the Picture Frame\nLets start by taking apart the picture frame.\nBend open the metal tabs on the back of the picture frame, and separate all the component parts of the frame.\nThere will likely be a glass cover to the frame - you will not need this for this project, so it can be reused or recycled.\nYou will be left with a frame outer (black), frame inner (wood) and the backboard.\nStep 2: Add Felt to the Backboard\nNext we are adding felt to the backboard, which will cushion the rolling surface of the dice tray.\nFirst, cut out a square of felt slightly larger than the size of the backboard.\nLay the felt fuzzy side down and peel of the adhesive backing.\nCarefully place the backboard down onto the adhesive side of the felt and press down to adhere. If the surface isn't completely smooth you can always peel back the felt and re-apply.\nUsing a craft knife carefully trim off the excess felt - leaving you with a perfectly felt covered backboard.\nStep 3: Add Fabric Suface\nFinally we will add the fabric that will be the rolling surface of the dice tray. This can be any fabric of your choosing, so is completely customisable.\nSimply cut your fabric to be slightly larger than the backboard.\nTake the frame outer and inner then on top place the face-down fabric and backboard. Push down into the frame and close into place using the metal tabs.\nStep 4: The Finished Dice Tray\nAnd thats it - you have now made a cushioned fabric dice tray.\nSince we didn't adhere down the fabric surface, if you want to change the design of the tray simply open up the back of the frame and replace with a different fabric design.", "879" ] ]

[ 10951, 163, 7274, 10558, 1784, 6335, 5290, 9363, 2449, 3800, 4599, 10377, 1933, 3242, 7, 6023, 170, 10990, 5204, 3144, 2998, 8783, 5522, 5762, 8506, 361, 8043, 5207, 8025, 3633, 7702, 2438, 11138, 9128, 6981, 6508, 10886, 10609, 205, 1076, 9202, 8746, 4306, 3574, 10659, 5195, 342, 3740, 9798, 2685, 9501, 10239, 939, 4936, 10340, 1286, 10522, 8578, 6173, 4881, 5560, 2695, 8821, 10370, 2833, 11414, 1844, 7164, 2574, 7749 ]

[ [ "Probability Density\nYou mentioned that the cities tend to keep within a \"home range\", if you will, of a defined size (up to the area of Mexico?) and defined shape (commonly trapezoidal?).\nEven if the city doesn't follow a regular route, it stands to reason that there will be areas and locations within this range which it visits more commonly and/or at which it remains for longer. I would expect these to include points or areas in which they can harvest resources, make trades, replenish supplies (water? fuel?) and perform maintenance.\nIf these cities have existed for long enough that they've pretty much established their home range and where they want to be within it, then mapmakers should be able to gather the information about where they've been and extract a pattern of \"probability density\": a graphical representation of where the city is most likely to be found.\nI would imagine two ways it could be represented on a static, paper map:\n1. As variably-shaded colour: similarly to how countries are represented on a political map, you could have differently-coloured shapes on a map that define the usual home ranges of the corresponding cities.", "783" ], [ "Where the city spends more time/visits more frequently, the shade of the color is darker; in the parts of the range it rarely visits, the shade is lighter/more washed out.\n2. As sampled past locations: the map contains a statistically significant number of past locations of the city marked as single dots of the appropriate colour. The probability of the city being in a certain area is expressed by how densely the dots in that area are clustered. (If there is a particular, exact location that the city often occupies, the mapmaker can cluster multiple marks immediately around it instead of stacking them on top of each other, since this would better express the frequency to the reader.)\nUsing this information, a reader of the map can hopefully make some informed guesses about where the city is most likely to be, and then seek news or rumour to confirm one or the other (if no instant communication is available).", "675" ], [ "Regarding each given domino as an edge in a graph connecting the vertices labelled from $[![0, k-1]!]$, with \"doubles\" $\\langle j,j\\rangle$ handled separately, we need to answer:\n* is the graph connected? In general this will be an easy question because most cases will have a much smaller number of vertices than edges. If the answer is \"no\", the problem sub-divides into the connected components of the graph.\n* how many vertices of odd degree are there? This determines the existence of a Eulerian path and so whether all dominoes in the current problem can be included, or otherwise gives initial information to assess which dominoes may need to be excluded. If there are zero or two odd-degree vertices, a Eulerian path is possible and all dominoes can be used.\n* for the case where a Eulerian path is not possible, we need to find short paths that link together odd-degree nodes whose removal will not disconnect the graph (but see extra note). These would constitute the dominoes that are not going to be used; the shortest paths that connect pairs of odd-degree nodes (allowing two such to remain) give the dominoes to set aside.\nExample adjustment, showing odd-degree nodes in gold and removed edges in red:\nEither as given or as adjusted by removal, a Eulerian path can found using e.g.", "433" ], [ "<PERSON>'s algorithm\nHandling doubles: These can be kept as a separate list; they are included if there is any other connection to that value (vertex). If consideration is made of which dominoes to ignore, if a double is attached to a node that otherwise has only degree one, this could change the optimum set of dominoes to exclude since the double would also then be unused.\nExtra note: finding the paths that connect the odd-degree nodes may not permit keeping the graph connected in some cases, even limiting that to a substantial disconnection (more than just leaving an isolated node), especially if the edges (dominoes) are relatively few and the vertices (values) many. Finding bridges in the graph would allow detection of this case; these can be found in linear time. Example graph:", "433" ], [ "There isn't any mapping from 3D to 2D that will preserve pairwise distances between all points. Using time as a measure doesn't fundamentally change anything about the problem, since instead of \"distance\" being measured in km/AU/lightyears, it's instead measured in hours/days/years - but you still just have a series of pairwise distances between points.\nYou could make a locally oriented map that accurately shows distances from your current location (A) to any other location (B or C). But this type of 2D map would not accurately represent the distance between B and C.\nBecause you cannot map directly from 3D to 2D and preserve distances, a subway-style abstraction might actually be just what you need. You simply label the subway \"legs\" with the true 3D distance between points, since you cannot measure the legs on the 2D subway map and get an accurate value.", "204" ], [ "One just needs to be aware that there will be distances that are not reflected in the visual representation of the subway map - some points that appear close together might actually be far apart, and some points that appear far apart might actually be close together.\nNote that this distortion is exactly the point of a subway map - it purposefully distorts distances in order to have a more visually pleasing layout. There's no reason you couldn't draw a map of the London Tube that perfectly represents the pairwise distances between all stations (it would just be a regular map), but that is antithetical to the whole impetus for the subway map in the first place. For the star map, you can't perfectly represent the distance in 2D, but you can still try to organize it in a way that minimizes distortions.\nIt's the job of the mapmaker to choose the representation to minimize that visual disparity, and to put those visually discordant distances in less important or less traveled legs. You can take advantage of natural \"projection planes\" to minimize distortions, leveraging the knowledge that galaxies and solar systems tend to be much wider than they are thick - projecting a galaxy top-down along its axis of rotation will only lose a fraction of that pairwise distance information (the projection distance is a good approximation of the 3D distance). An edge-on projection, on the other hand, would lose a great deal of that information.", "204" ], [ "In humans, I'm pretty sure it wouldn't, for the reasons listed at the end of this answer. In other creatures, though, perhaps if the ear simply senses the energy of the sound waves reaching it, and reports that as a fluctuating signal. There would likely need to be multiple \"ears\", that trap sound from various directions, since it would be impossible to have more than one person talking at once without being able to have the brain focus in on one voice; the overlapping volumes would change the meaning of the speech. The more ears they have, the better the brain would be able to process the input and focus in on individual voices. Perhaps a series of several pits around their head, each one of which senses the relative energy of the sound waves reaching it.\nEven then, they would be much more likely to develop a language based on timed pulses, ala Morse code. For the creatures to not develop this, they would have to have a limitation in their ability to sense passage of time. The time sense of these creatures would have to fluctuate wildly, to the point that they would be unable to reliably tell the difference between a dot and a dash. Perhaps their brains are sort of like modern computer processors, which change processing speed from moment to moment as needed, slowing down to conserve energy, and speeding up when decisions need to be made; with the sense of the flow of time adjusting accordingly.\nWith these limitations, it would rule out the language being based on a constant sound with modulated volume; it would need to be repeated bursts of sound with each burst being at a constant volume throughout, since timing can't be considered. It might take the form of some sort of barking sound, with the barks varying in volume.", "350" ], [ "A conversation might be begun by an individual \"barking\" a few times to set the initial volume of the conversation. If the other individual wishes to speak (or loses track of the conversation) they might break in in the same way, and wait for the other to make a statement relinquishing control of the conversation before saying their piece.\nYou are correct that relative volume would be necessary. That could be in one of two manners: volume relative to the previous sound burst, or relative to the initial calibrated volume. Making it relative to the previous burst would require recalibration if the speaker reached the top of their vocal range. One way to do this is being limited to three phonemes (quiter, same, and louder) so that after a long series of louder phonemes one could modulate very far down in volume in one step without changing the meaning.\nStill, very significant hurdles would need to be overcome:\n1. Any relative movement between speaker and listener would have to be carefully compensated for, since increased distance would change the volume\n2. Sound is usually somewhat focused; turning your head (or sound generation organ) slightly to the side would change the volume, and therefore the meaning of your statement\n3. Any conversation would have to begin with an exchange of volume calibration noises, and if one got distracted in the middle, non-verbal communication would have to be used to reset the calibration, making extended conversations difficult\n4. Changes in ambient noise can affect the conversants unequally, leading to loss of calibration even in the best situations", "350" ], [ "How to calculate rainfall; record highs\nThere are numerous programs and resources that can be used to ascertain pretty exactly the average temperature and general climate of a region.\nBut is there any way to get a quantitative estimation of rainfall or record high and low temperatures in a region?\nI know general trends like, since my region is situated on the edge of the polar front, with an ocean to its east, high mountains to the west, and strong persistent westerly winds, it probably gets a considerable amount of rain. Or, I know that due to the lack of large landmasses to the north of my region, it probably will not have the comparatively cold record lows found in places like the NW US or Eastern Europe.\nFinding an Earth-proxy isn't exactly correct either, since my reliable modelling for average temperatures suggest that the climate regime for my region is not completely equivalent to South Chile (my closest proxy). While these little differences may not mean too much for average temperature prediction, they can introduce unintended consequences to your world.\nFor example, Puerto Montt has the closest climate to my region's captial. They are remarkably similar in terms of year-round average temperatures and in rainfall (though mine shows less seasonality). However, in the winter months, Puerto Montt has an average low of roughly 3.5 C. My region's capital has average lows of 1.9 C in winter.", "650" ], [ "This difference is negligible for getting a sense of the average climate, but it has a massive impact on other variables. With its milder winters, Puerto Montt experiences snowfall rather infrequently and sporadically, mostly in July. However, my region's capital gets 7-8 reliably snowy days a year that can happen as late as October, an event which rarely if ever happens in Puerto Montt. So, while proxies may be useful for parameters which are easily defined or that you can already predict, they are not useful for estimating other variables. I would expect record temperatures to be especially susceptible to this.\nIn short, qualitative analysis and proxies are insufficent. Are there any ways to get real quantitative numbers for things like monthly record temperatures?", "867" ], [ "I have now played 2 games of Black Angel; I have also played Troyes 4 times, all in the past year. I would like to do a comparison of the two games for those who have perhaps played and enjoyed Troyes and would like a rundown of how the two games differ, as clearly they are siblings.\nTL;DR\nThe game state in Black Angel is easier to read because the game has 3 single-use currencies (ships, resources, debris) and one multi-use currency (robots).\nBlack Angel has a lot more going on in terms of upkeep/fiddliness.\nThe end of game timer is harder to get a read on in Black Angel as the game moves forward in many small irregular steps instead of a few regular steps.\n(b) The current score is much more clear: Black angle has a score track whereas Troyes has private scoring tokens. Black angle has face-up end of game scoring tiles that score linearly, whereas Troyes has hidden scoring that scores non-linearly.\nBlack Angel has a technology tableau which provides a bit of engine building that did not exist in Troyes (outside of banking future actions)\nTroyes' core action selection mechanic is more interesting than Black Angel (choosing up to three dice vs. exactly one).\nIn Black Angel, even though the missions and technology are abstract, the theme feels more integrated into the mechanics.\nEdit: After three plays, I can am beginning to feel that the sum of the differences between Black Angel and Troyes result in a game that feels more wide-open. You often feel like you have a number of good options on your turn; Black Angel feels like exploration, whereas Troyes feels like mitigation.\nActivities vs. Missions\nTroyes: Activities come up randomly, you see only 25% of them each game. Activities may be purchased (with coins) and you get to do the activity the first turn you place a meeple there. They can be selected by all players, but those who come first get victor point bonuses. One you buy-in, you have access to that activity for the remainder of the game, unless you choose to abandon it to reuse that meeple. Some of these are immediate effects, and others give you the potential for stronger actions later in the game. The suits (yellow/white/red) have very different focuses and personalized artwork. Activities each feel very unique.\nBlack Angel: Players draft missions and hold them in their hands. Those missions are either one time or ongoing. They then play them out onto the conveyor-like space board. The ongoing missions all have immediate effects when activated, but must be activated on a separate turn after playing them out. Most are time-limited (will eventually fall off the board).", "349" ], [ "When they fall off the board they may be worth 2 points at the end of the game (if you attach them to the right scoring tile). One-time missions activate when they fall off of the board, but you do not need to invest any more actions into them.\nThe suits (yellow/green/grey) are symmetrical feel kind of \"samey\"; Missions do not even have titles or artwork. Players own missions and gain a benefit from other players using them (for ongoing missions). Missions are limited (only two players can dock ships with them at one time). Missions must be paid for with \"ships\" as well as robots.\nMeeples vs Robots\nTroyes: Meeples are drafted with Influence, a common currency that is also used for dice manipulation. Meeples give you access to dice and to activities. Meeples can abandon their posts at any time to be used in a different capacity.\nBlack Angel: Robots are added through specific actions in the game, choosing to draft more robots via missions or technology activations. Robots are used to gain more dice and to work at missions. Robots in workstations (where they give you more dice) must be moved to the \"breakroom\" before they can be assigned to missions (this doesn't really happen). Robots in ships may be flown between missions to change what actions you have available.\nDice Manipulation\nTroyes: Can flip up to three dice for a high cost, or reroll one at a low cost. Uses a common currency for dice manipulation and drafting new meeples (Influence). Influence can score at the end of the game, but only if the secret scoring card is in play. You can only manipulate your own dice.\nBlack Angel: A separate currency (debris) is used for dice manipulation. The manipulation is always deterministic (one cube flips one die). This changes a 0 to a 2 or a 1 to a 3. Debris can score at the end of the game if you draft the appropriate scoring tile. Generally, you can only manipulate your own dice.", "50" ], [ "To elaborate on and combine a few other answers, consider that the Earth's magnetic north is not in a constant position, so it is not the factor in how lat/long coordinates are determined. Rather it is the axis of rotation as has been pointed out by others.\nThe equator is determined by being the great circle (circle which circumscribes the geoid of the planet), upon which twice per year (on the equinoxes) the sun travels exactly 180 degrees from horizon to horizon in a perpendicular fashion. Leap years are a thing because there is a slight difference in the time it takes for the earth to complete a single orbit of the sun vs. the period in which two equinoxes occur.\nIn your case a similar equator could be determined by observing the relationship between the body which the astroid orbits vs any 'wobble' along its axis of rotation (although this may take longer than a single 'year' or orbital period about the body.) The 2 points at which any two lines that are perpendicular to that equator intersect are its 'poles'. Lines which then intersect at a 90 degree angle at the poles can be used as meridians, the points at which those meridians intersect the equator are effectively arbitrary (the prime meridian is Euro-centric due to the fact that European cartographers defined it, not for any special geometric reason.)\nThe last step is then determined by math which describes projecting the surface of the asteroid to the abstract sphere that these lines define, surveying specific landmarks (natural or artificially placed) to act as well-known points which can be surveyed against as a reference system for any other point on the surface, allowing you to triangulate coordinates.", "204" ], [ "These landmarks need to be offset along either the x or y axis from one another.\nOn a personal note I am also a fan of the answer which mentions 'geohashing' for modern cartographical applications. I have worked on an abstract specification known as 'Discrete Global Grid Systems' with the Open Geospatial Consortium which is conceptually similar and I'd encourage you to look into it if this sort of thing interests you. Its basis divides the sphere defined by an equator and meridians into a grid of triangles which is then projected to the surface of the body. Ironically, this is shown in the illustration of the robot in the left sidebar of this site. However your question specifically mentions coordinates, which a hashed addressing system does not provide.", "441" ], [ "Can I take advantage of a nearly banded A in AX=b?\nI am working on a 1D drift-driffusion problem in a finite-difference (FD) approach.\nI hade 3 equations per node ($3N$ in total): electron continuity $E_i$, Poisson $P_i$, hole continuity $H_i$. With corresponding variables: electron concentration $n_j$, potential $V_j$, hole concentration $p_j$.\nBy rearranging the problem has a banded matrix, the Jacobian $A$ takes the following form, with shape $(3N\\times 3N)$\n$$A = \\begin{pmatrix} A_{1,1} & A_{1,2} & & & & & \\ A_{2,1} & A_{2,2} & A_{2,3} & & & & \\ & A_{3,2} & A_{3,3} & A_{3,4} & & & \\ & & \\ddots & \\ddots & \\ddots & & \\ & & & A_{N-2,N-3} & A_{N-2,N-2} & A_{N-2,N-1} & \\ & & & & A_{N-1,N-2} & A_{N-1,N-1} & A_{N-1,N} \\ & & & & & A_{N,N-1} & A_{N,N} \\ \\end{pmatrix}$$\nwhere\n$$ A_{i, j} = \\begin{pmatrix} {\\partial E_i}/{\\partial n_j} & {\\partial E_i}/{\\partial V_j} & {\\partial E_i}/{\\partial p_j} \\ {\\partial P_i}/{\\partial n_j} & {\\partial P_i}/{\\partial V_j} & {\\partial P_i}/{\\partial p_j} \\ {\\partial H_i}/{\\partial n_j} & {\\partial H_i}/{\\partial V_j} & {\\partial H_i}/{\\partial p_j} \\end{pmatrix} $$\nOwing to that data structure, I have been using scipy.linalg.solve_banded to solve for $X$ in\n$$AX = b$$\nwhere $b$ is a $(3N \\times 1)$ shaped vector.\nMy problem comes from that I want to add an equation that controls the potential at one end (say on the left) based on the value of total fluxes of $n$ and $p$ at both ends.\nAs a result the additional equation depends on $(n_1, V_1, p_1, n_2, V_2, p_2)$ but also $(n_{N-1}, V_{N-1}, p_{N-1}, n_N, V_N, p_N)$.\nTherefore, if I was to include this new equation in $A$ to form a $(3N+1 \\times 3N+1)$ Jacobian $A'$, the bandwith would suddenly become much larger. Though I can optimize this by inserting the new equation in the middle row of $A$, the banded representation would remain very sparse.\nMy question is then: is there a way I can solve for $X'$ in $$A' X' = b'$$\nwhile keeping the advantages of the banded structure of $A$?\nEDIT addressing comments\nHere is a visual example of the Jacobian before (left) and after reordering (right).", "490" ], [ "The last column/line, highlighted in yellow, is the additional equation that fails to fit the banded structure. Elements in dark gray background are non-zero, elements in white are zeros, elements in light gray background are zero, but a future version of my physical could in principle make them non-zero so an ideal solution would not exclude that possibility.\n(click to enlarge)\nDisclaimer: I do not pretend to be the author of this ordering method. I have read it a few years ago in a software manual I believe ...", "614" ] ]

[ 5997, 3883, 5851, 3358, 9215, 10081, 2016, 1266, 9620, 6501, 8705, 957, 8413, 7201, 7249, 4844, 3987, 11285, 11207, 8991, 6588, 991, 8122, 3650, 3620, 10464, 1098, 4702, 7893, 2782, 498, 7019, 6106, 5979, 9954, 3491, 977, 8697, 8560, 888, 5157, 5380, 5538, 10661, 5363, 8313, 7731, 5723, 10999, 5703, 7036, 4184, 6082, 8834, 7609, 8759, 9583, 1430, 6238, 2167, 4112, 9490, 10826, 7574, 9483, 5925, 1338, 4, 6102, 91 ]

[ [ "\"Is it policy or law?\"\nI can't stand the entitlement of people. If I say it's policy it's policy. It doesn't matter if it's me, the governor or the pope himself. If I say no, the answer is no. I'm not risking my job for an eighteen year old (freshly eighteen too.", "806" ], [ "like this month.) to stay in our 21+ hotel.\nAnd, the guy had a whole story of how he booked using his work's discount rate for him and his \"fiances\" vacation. A cooperate business rate. Not for personal use, so homeboy's going to have a problem with his people too.\nI'm trying to tell him that in our state, almost every hotel besides the sleazy places are 21, for legality/liability reasons. Then he pops off with \"so is it policy or law?\" Well, it's a firm 21 from my manager (we literally just had a whole email discussion about it.) so, <PERSON>. It's a hard, sorry.", "806" ], [ "<PERSON>\nThe American Dream is a nightmare\nIf I had a nickel for every time someone told me, \"he seemed harmless so I didn't say anything,\" I would be a very wealthy woman.\nThey've been saying this long before 1956 and people are still saying it.\nWe excuse or overlook dangerous behavior and signals from men all of the time. ALL OF THE TIME. Society encourages us to do it.\nThat's what's happening in The Unguarded Moment. <PERSON> (<PERSON> in her only non-swimming role) is a high school teacher who gets intrusive questions about her marital status, leers from her fellow teachers, and is now receiving threatening anonymous notes.", "861" ], [ "Which she writes off first as the result of a student crush.\nAnd she's encouraged to do that. Because boys will be boys and attractive women should really be married and not out there tempting teenagers.\nSo it's through this lens that I think we have to view <PERSON>' reactions and behaviors, which it is easy to find questionable. When everyone around you is telling you that you're the problem, well it's hard not to listen sometimes.\nIt's actually a pretty interesting film with a couple of decent performances. <PERSON> makes for a well written lead and both <PERSON> and <PERSON> are quite good.\n<PERSON> co-wrote the screenplay. Apparently, her original plan was to star but things happened and they went with <PERSON>.", "657" ], [ "Chat GPT for the win\nIn the banter of <PERSON>. Describe the difficulties trying to get people to automatically fill prescriptions and corporations berating their employees to get people to sign up for autofill\nWhat's the deal with filling prescriptions, am I right? You go to the doctor, they give you a little piece of paper and you're supposed to take it to the pharmacy and magically your ailment disappears. But the real magic is getting people to actually fill those prescriptions! I mean, have you ever tried to get someone to fill their prescription automatically? It's like pulling teeth! \"Oh, I don't know if I want to commit to that,\" they say. \"What if I don't need it anymore?\" What if you don't need it anymore? Then you can just cancel the automatic refill! It's not like you're signing a blood oath! And then there's these corporations, right? They're always berating their employees to get people to sign up for automatic refills.", "360" ], [ "\"Come on, <PERSON>, you gotta get those numbers up!\" They're like the mafia! \"You gotta make your quota, or else.\" It's like, can't we just let people make their own decisions? We're all adults here, right? But no, they gotta push and push and push. It's like, what are they afraid of? People actually taking control of their own healthcare? That's the real prescription we need!\nChatGPT Mar 14 Version (https://help.openai.com/en/articles/6825453-chatgpt-release-notes). Free Research Preview. Our goal is to make AI systems more natural and s afe to interact with. Your feedback will help us improve.", "618" ], [ "Title: Administrator casually warning me about layoffs??\nI was chatting with a higher-ups executive assistant this morning. We were just talking about some health problems she'd been having and then all the sudden, she got kinda quiet and asked if I'd heard that the Board was considering layoffs. I. had not.", "1015" ], [ ":/ She said nothing was for sure yet but there's been a lot of public funding issues lately. She wasn't supposed to say anything but wanted to warn me to start looking for other jobs. How worried should I be? This place has been having funding issues for ages and every year they say something like this might happen. Has this ever happened to anyone else?", "536" ], [ "Dog Day Afternoon\nThank God I did not know anything about this movie because the experience I just had was transcendent.\nThe opening was so funny I was asking myself if this had been a comedy all along, until I realized that the absurdism was just a reality of the overall situation. It’s funny, yes, but it’s also tense and thrilling and tragic all over, to the point where I sobbed my eyes out during that one phone call towards the end.\nWhat a heartbreaking little moment that oddly encapsulates the personal cost of queerness, the lengths to which society can push you by means of rejection.", "471" ], [ "When a society doesn’t afford you dignity, you are forced to demand it.\nAlso, the actual bank robber <PERSON> is playing was as hot, if not hotter, than <PERSON> himself. No wonder the tellers were like “whatever you say, handsome”. Like, same.", "86" ], [ "Private Life\n\"I know that's harsh but that's honestly what I feel. Relieved. I don't think I even want to have a kid anymore. I just want my life back. I mean, look at us.", "975" ], [ "We're a mess. It's like we're not even in a relationship, let alone a marriage. I'm not your husband, I'm just some guy that injects hormones into your ass every night.\"\nA delicate movie that captures the ups and downs of a middle-aged couple’s attempt to conceive and how the complexity of IVF procedures consumes their marriage. Very funny, real, and nuanced. Great performances by <PERSON> and <PERSON>.", "1009" ], [ "The French Dispatch\nEvery film <PERSON> makes feels like a love letter to cinema and this was no exception.\nThe French Dispatch is four stories in a film, which works really well with his style. In everyone of them he gets to explore different sides of the magazine and the city. And introduce a whole other set of quirky characters.", "594" ], [ "It's a smart choice, because nothing outstays it's welcome or drags on for to long.\nThe cast is huge, it feels like everyone is here. You just don't say no when you get asked for an <PERSON> film.\nFor me the last story, with <PERSON>, was the strongest or most fun. It's a crazy journey from a dinner in the police precinct to a chase through the city streets to catch a kidnapper.\nI laughed, I cried and I marveled at every frame <PERSON> created with his team. He used every trick in his playbook and somehow it all came together in this wonderful film.", "529" ], [ "You Are So Hard To Find, We've Been Looking All Over For You!!!\nI love it when people come to the store and the first thing uttered is an outburst \" you are so hard to find, we've been looking all over for you, no one knows where you are\" and then rage about parking which is a topic I honestly don't give a fuck about. All this and they have actually arrived on time.\nMy regular reply is: \"We are right here.", "866" ], [ "In this room. It's always hard to find somewhere the first time\". Sometimes I go to stage 2: \" the whole front of the building is plasti-wrapped with our name and logo and there is a 4 meter (15') sign out the front\".\nWhat they are really saying is how unorganized they are and that they don't know how to access information services, check Google information in advance.", "1015" ] ]

[ 9558, 3953, 5605, 6004, 4940, 8665, 3599, 645, 352, 10911, 7458, 5457, 322, 7419, 3110, 10108, 7429, 10146, 10298, 5299, 5749, 1976, 5061, 1926, 3524, 7688, 7208, 11245, 8417, 9054, 11012, 2365, 1547, 717, 6659, 10671, 5109, 6303, 198, 8861, 1290, 201, 8112, 2336, 9173, 4057, 11181, 3277, 6753, 3592, 9219, 7065, 3129, 10471, 29, 2145, 10518, 9408, 5151, 7735, 125, 3000, 1526, 2952, 2728, 7336, 11252, 514, 1572, 4231 ]

[ [ "Exotica\nThe tension here in the way this uses the knowingly false constraints of hip post-Twin Peaks 90’s deadpan semi-surrealist arthouse drama (or, in this case, the knowingly false walls of a strip club) as a pressure cooker for authentic undiluted Toronto freak shit makes for one of the most potently fucked vibes I’ve ever seen. I think <PERSON> overplays his hand once or twice to the point that it starts to border on parody (parroty?), but it’s also probably the most a movie has legitimately upset me in years (nearly had me throwing up by the end), which counts for a lot! Gotta be the least erotic thriller of all time - ostensibly a movie about tax fraud!", "306" ], [ "The Curse\nSometimes you have to go to extreme lengths to make your point! <PERSON>’s screen presence is a bit of a complicating and frustrating factor for me, although all three leads are uniformly excellent - this is really compelling as a super-weird slow-motion <PERSON> moving-parts-in-a-pressure-cooker thriller about white-saviorism, gentrification, New Mexican liberalism, contemporary art and reality TV (the specificity and depth of the venom here, my god!), and the much-discussed WTF ending actually makes about as much sense as anything else would in that context, but in casting himself <PERSON> places this firmly within his artistic project of finding new ways to expose himself as pathetic on television, which has pretty consistently held diminishing returns for me since Finding Frances, when the interiority actually came as a surprise rather than being par for the course. You mean <PERSON> plays a cosmic cuckold with a micropenis? You mean he’s gonna get grilled on camera about his personal failings and the end of his last relationship? Or, tee-hee, is it a show about why and how the constraints of reality TV might make him look like a loser? Haven’t we been through this before? Is there really anything more to be milked out of the <PERSON>-both-<PERSON>-and-<PERSON> stuff? I’m not so sure, especially now that it’s had a perfect formal payoff with “the pottery scene.” Viewed in that light, I’m hoping this is a final kiss-off to that side of his work, but I was saying that that about The Rehearsal too, so I’ll believe it when I see it.\nAnyway, whatever it all amounts to, it’s pretty magnetic television. I don’t think the 10 episode format does it any favors - it’s not that it’s too long, exactly, as much as it feels like a pitch for a limited series of 4 two-hour episodes cut into a full season; those previously-ons are obviously at least somewhat part of the show’s parodying of TV, but the show itself isn’t really doing a ton of that, so...", "282" ], [ "they mostly just end up serving the purpose of reminding the viewer what themes they should have in mind for the next 45 minutes. The amorphousness is by and large perfectly harnessed within the episodes themselves (<PERSON> as director is the biggest revelation here, just unbelievably good stuff), although Episode 8 in particular stuck out as an exception to that, but as a Season Of Television I’m not sure how functional it is. Happy to settle for electrifying, alienating, hysterical and perfectly-performed, tho!", "282" ], [ "Memory of Red\nIt’s really endlessly frustrating to me when a <PERSON> film (impossibly textured, deeply engaged with film form in really exciting and fresh ways) inevitably ends up becoming a <PERSON> film (lines go brrrrrrr), feels like just starting to lose yourself in a <PERSON> when suddenly it’s a <PERSON>. I like both, but the whole point is that one is overpowering in its subtleties and hidden depths and the other is hard-edged, loud and surface level (not in a philosophical sense necessarily but a flatly aesthetic one), and so often they don’t really comment on or constructively add to each other, cuz how or why would they be expected to? The film that followed this one in tonight’s screening, Barva (not on tMDB/LB at the time of this writing), on the other hand, gave me an unexpected amount of meaningful points of conversation between the complexity and nuance of <PERSON> the experimental filmmaker engaged with the process of making art within the world and the whirling abstract beauty ranging from serene to frenetic of <PERSON> the animator, with none of the tacky goofiness of <PERSON> the wannabe psych rock music video director - easily a highlight of the program, really beautiful stuff", "80" ], [ "Natural Born Killers\n<PERSON> had a lot of chips in 1994 and he cashed them in on a movie that on some level is his crowning achievement, though if like me you think he's often a fundamentally unserious filmmaker - a zeitgeist-surfing, fast-twitch opportunist as opposed to a vanguard artist - that's not a compliment. Points for managing to shove something mostly free-form and story-less into several hundred American cinemas, and for a few effectively quasi-surrealist touches, like the sitcom of the damned starring <PERSON>, which really does make you sit up straight and pay attention; it’s appalling, and inspired as satire. But for the most part, NBK's hyper-formalism, switching formats and framings, shoehorning in Godardian text and turning numerous scenes into rear-projected palimpsests, only exacerbates the material’s essential and irrecuperable paltriness. Having worked very hard with a host of talented people to develop a distinctive cinematic language, <PERSON> uses it to simply say the same thing, over and over again, and not too convincingly. While it might seem like a cop out to ding a movie like this for its gratuitousness, it's more that said gratuitousness - on every front, from acting to editing to gore to needle-drops - is ultimately the wrong kind of alienation effect for this material, which needs, to paraphrase <PERSON> on Peckinpah, to have some sting in its death.", "698" ], [ "<PERSON> gives us Wild Bunch -style scorpions aplenty, but no sting; instead of using cartoon stylization to deepen and contextualize real-life horror (sexual and emotional abuse; the predations of the carceral state) he ends up reducing (and banalizing) his subject and its potentially juicy complexities into a display of lizard-brained showmanship. I thought on this viewing of <PERSON> tough, unyielding Henry: Portrait of a Serial Killer, and how one short, horrifying scene involving a television suggests most of what <PERSON> is preaching about here and more; I thought of the shivery lyricism of Badlands and the blocky naturalism of The Honeymoon Killers and the bravura camerawork of Man Bites Dog and even the po-mo pedantry of Funny Games, which has aged into even more of a critical pinata than NBK (<PERSON> having <PERSON> to go full-scold mode against \"enemy films\" that had their gore and ate it too) and realized I'd rather be watching its precisely-tuned situationist shtick. For a movie that means to castigate the history of representation and the complicity of mass media in a culture of violence, Natural Born Killers lags behind the pace-setters in its own genre and even looks draggy compared to unpretentious inheritors like <PERSON>/Taylor, whose movies are far less pious about revelling in shit in order to say something about our collective pungency. One note about <PERSON> Aussie let TV trash-humper <PERSON>: this could have been a brilliant performance if it had been allowed to stand apart tonally from the rest of the movie, on its own plane of reality, <PERSON>-style. Integrating the character into the second half of the film - and into the prison riot section that finds <PERSON> going for broke and getting there, especially via <PERSON> rape attempt on <PERSON> -is a real mistake, one among many.", "698" ], [ "The Opposite of Sex\nThe Mutual Cinematic Education of José and Camilo #38 (<PERSON>’s Choice)\nSurprisingly post-modern in its insane mix of 90’s irony poisoning and genuine sincerity. A gay writer/director throwing a lot of preemptive (?) homophobia at the wall in order to expose the real complexities and liberate himself of the audience’s baggage.\nMy boyfriend says that seeing this when he was a teenager made him feel a lot stronger and liberated as a gay teen, especially given the lack of conversations about queerness at the time. It makes it all the more special in hindsight; that we also get to indulge in messy and complex art that’s as messy and complex as our own experience.\nAlso, <PERSON> is a TREASURE.", "378" ], [ "Fallen Leaves\nPretty much my platonic ideal of “romantic comedy”; <PERSON> pairs his mastery of ethnographic working-class detail with a genuinely hilarious (and moving!) love story, beautifully photographed (one could describe the aesthetic here as “Neorealist <PERSON>”) and filled with curiously memorable conversations and side characters…really loved this one, pretty easily my favorite thing I’ve seen from <PERSON>. Also manages the feat of packing in an absurd amount of cinephilic in-jokes without ever feeling too cutesy. Come for the Finnish cover of “Early Morning Rain”, stay for the swooningly romantic trip to the theater to see The Dead Don’t Die, etc.", "217" ], [ "Perfect Days\nA little overly cute for me — semi-structuralist arthouse for your parents to enjoy. Great leading performance.", "657" ], [ "Gets a lot of mileage out of its depiction of the quiet joys of routine. Ends strongly.\nBut I absolutely hated the B&W dream sequences. And while I’m complaining: props to <PERSON> for choosing a (unfortunately kinda bad) Stones song that even I was not familiar with, but other than that, I was a bit disappointed by the bland obviousness of this much-hyped dad rock soundtrack…your mostly plotless, needledrop-focused movie about a music collector’s got a prominent “Brown Eyed Girl” sequence? It opens with “House of the Rising Sun”?!? “Dock of the Bay”???? “Feeling Good”???? Cmon!!!!!!!!", "144" ], [ "The Irishman\n“He’s dead? Who did it?”\n“Cancer.”\nI found this a touch overrated upon release, but <PERSON> — once you’re keyed into <PERSON>’s thematic goals regarding the pathetic, “just following orders” nature of his protagonist here, this thing just sings. I unfairly derided the aesthetic here as having “Netflix sheen” back in the day, and while the look is perhaps overly digital and clean, it still looks — let’s be real — heads and shoulders above most anything else being made at the moment. <PERSON>, <PERSON>, and especially <PERSON> are all delivering performances that rank among their very best, the script is absurdly detailed and honestly impressively subtle…it’s a fucking masterpiece.", "475" ], [ "Easily better than Casino and among <PERSON>’s best. One of the great films about the act of dying. Bring on Flower Moon.", "529" ] ]

[ 3217, 8696, 3802, 2811, 10319, 7594, 3283, 1487, 9107, 9867, 6786, 7206, 11012, 7620, 5119, 10800, 2750, 8175, 7106, 7943, 11313, 3730, 385, 7326, 4169, 9517, 10850, 9930, 6624, 10223, 6960, 4359, 7667, 1373, 11400, 6901, 9086, 6829, 562, 135, 3085, 5743, 736, 8809, 9642, 8817, 11220, 3301, 5610, 242, 5499, 6891, 7960, 7547, 6785, 7816, 10803, 7568, 7598, 5042, 10931, 4696, 5426, 8978, 2225, 5920, 3119, 3453, 1258, 5961 ]

[ [ "PCB Necklace V1\nIntroduction: PCB Necklace V1\nHey Everyone, so here's something cool.\nA PCB Necklace or Pendant powered by an Attiny13A.\nThe goal here was simple, to make a small Blinky board that can be attached to a chain so we can wear it like a locket or pendant.\nIn this Instructables, I'm gonna show you the whole build process of this PCB Necklace.\nSupplies\nThese are the stuff I used in this built -\n* 0603 Blue LEDs x24\n* Custom PCB which was provided by PCBWAY\n* Attiny13A\n* AO3400 N channel mosfet x4\n* 10K 0603 Resistor x4\n* SMD Coin Cell holder CR2032\nStep 1: Working of This Pendant\nThere are a total of 24 LEDs in this Pendant, I've divided LEDs into pairs of 4.\nThis means 6 LEDs are connected in parallel and they are driven by a single AO3400 N channel mosfet. there are a total of 4 of these which control 6 LED segments each. These 4 MOSFETs are then controlled by an Attiny13A, I've added a button with its D4 Pin which starts the LED sequence.\nhttps://www.tindie.com/products/makerpals/valentine-pendant/\nBuy from here\nStep 2: Preparing the Board\nI've prepared this PCB in the shape of a tear which I first modeled in Tinkercad.\nAfter preparing the Basic shape, I exported it into fusion360 so I could export the DXF file from it as my OrCad PCB Suit only imports the DXF file for making PCB Layer. After importing the Tear Shape in my PCB suite, I prepared the Board Schematic first that consists of an Attiny13A driving four different N-channel mosfet setup which is then connected to a total of 24 LEDs.", "982" ], [ "After finalizing the schematic, I exported the netlist and prepared the PCB by using the imported Tear shape as a reference.\nStep 3: Schematic\nStep 4: Getting PCBs From PCBWAY\nAfter completing the design, I uploaded the Gerber data on PCBWAY's quote page, I selected the solder mask color which was RED and placed the order.\nAfter placing the order, I received the PCBs in a week and the PCB quality was pretty great.\nThis shape is completely random so it's pretty hard to make but they did an awesome job of making this PCB with no error whatsoever.\nYou guys can check out PCBWAY If you want Great PCB Service at an Affordable rate and low price.\nStep 5: ​ASSEMBLY PROCESS\nAfter unboxing the PCBs, I started the assembly process which had the following steps.\n* Solder Paste Dispensing\n* Pick & Place Process\n* Hotplate Reflow\n* LED Testing\n* Adding Coin Cell holder\n* Programming\nStep 6: Solder Paste Dispensing\nThe first step is to apply solder paste to each component pad.\nI used a normal Sn-Pb solder paste which has a melting temp from 140°C to 270°C. After Adding solder paste, we move on to the next process which is the \"PICK & Place Process\"\nStep 7: Pick & Place Process\nI then used an ESD Tweeaser to carefully pick and place each component on their assigned place one by one which took like 30 Seconds tops but the result was a perfect PCB with all the components placed in their location.\nStep 8: Hotplate Reflow\nAfter the \"PICK & Place Process\", I carefully lifted the whole circuit board and place it on my DIY SMT Hotplate which is also homemade just like this project.\nAfter a Few mins when the hotplate reaches the Solderpaste melting TEMP, all the components will get soldered by this Hot Reflow process. We then remove the PCB from the Hotplate to cool down all componenets and board surface.\nStep 9: Testing LEDs Continuity\nBecause we are using LEDs here, it's crucial to check whether LEDs are soldered properly or not.\nI used a normal Multimeter set in Diode checking mode, we connect the probe of the multimeter to the Anode and Cathode of leds in right polarity. If LEDs are soldered properly, all LEDs will glow. If there's any soldering error they won't glow.\nStep 10: Coin Cell Holder\nAfter testing the LEDs, we move on to the next step which is to add a Coin cell holder to the bottom layer of the PCB.\nAfter this the board is almost completed, now we just have to flash the Attiny13A with the main sketch.", "472" ], [ "Diamond Shaped PCB Necklace\nIntroduction: Diamond Shaped PCB Necklace\nHey Everyone how's it going.\nHere's something super cool, a Diamond-shaped PCB Necklace powered by an Attiny13A.\nThe goal here was to make a Wearable Necklace or jewelry by using a PCB and a few LEDs to make a combination of Electronics and Wearable Jewellery.\nThe heart of this Project is an Attiny13A that controls all the LEDs present onboard, also this pendant or necklace is powered by a CR2032 Coin Cell that is on the bottom side of the board.\nThis Instructables is gonna be about the whole built Process of this Necklace so let's get started.\nSupplies\nFollowing were the materials I used in this built-\n* Attiny13A\n* Custom PCB\n* LEDs\n* AO3401 Mosfet\n* 10K resistors\n* CR2032 Coin Cell with its holder\n* Chain for necklace\n* Solder paste\n* Arduino Nano for Programming Attiny13A\nStep 1: Schematic\nThe schematic of this PCB was pretty simple, I've placed a total of 12 LEDs on this board, and 3 LEDs are connected with a single Mosfet, to drive 12 LEDs, I used 4 Mosfets. Attiny13 Controls the gate of each Mosfet and we can change the state of Attiny13 by using the toggle switch.\nI've also added a CON6 Header Pin for flashing the Attiny13A, I will later use my Arduino as ISP Setup to connect through this CON6 Pin and flash the Microcontroller.\nStep 2: PCB Design\nI prepared a Diamond Shaped PCB Board with a hole in the top for mounting the chain with this setup. I placed 3 LED Pairs on one side, I did this with the remaining 3 LED Pair and then put the attiny13A at the center part of the board.\nI tried to keep this PCB as Small as possible as it's a wearable device that one will wear all day so by reducing its size, we are reducing the overall weight as well.\nStep 3: PCBWAY\nAfter completing the design, I uploaded the Gerber data on PCBWAY's quote page, selected the solder mask color which was White, and placed the order.\nAfter placing the order, I received the PCBs in a week and the PCB quality was pretty great.\nThis shape is completely random so it's pretty hard to make but they did an awesome job of making this PCB with no error whatsoever.\nYou guys can check out PCBWAY If you want Great PCB Service at an Affordable rate and low price.\nStep 4: Error in the Design\nHere's a small mistake I made while designing the board, I forgot to double-check the Mosfet PAD that I made for this project, I made the pad of Mosfet a little smaller than my existing footprint as this PCB was small and so I reduce the side of Mosfet Pad to save space.\nI forgot to add a soldermask layer on the Pad of Mosfet that I created and this resulted in a PCB that doesnt have any Soldermask opening for soldering Mosfet with the PCB.\nWire traces were all in their place so I used a tweezer to scratch the solder mask in place of mosfet Pads and this revealed copper terminals that I can solder mosfet with.\nStep 5: PCB Assembly\nthe PCB Assembly Process will have the following steps.\n* Solder Paste Dispensing\n* Pick & Place Process\n* Hotplate Reflow\n* LED Testing\n* Programming the Attiny13A\n* Adding Coin Cell holder\nStep 6: Solder Paste\nThe first step is to apply solder paste to each component pad.\nI used a normal Sn-Pb solder paste which has a melting temp from 140 to 270 °C.\nAfter Adding solder paste, we move on to the next process which is the \"PICK & Place Process\"\nStep 7: Pick & Place\nI then used an ESD Tweeaser to carefully pick and place each component in their assigned place one by one which took like 30 Seconds tops but the result was a perfect PCB with all the components placed in their location.\nStep 8: Hotplate Reflow\nAfter the \"PICK & Place Process\", I carefully lifted the whole circuit board and place it on my DIY SMT Hotplate which is also homemade just like this project.\nAfter a Few mins when the hotplate reaches the Solderpaste melting TEMP, all the components will get soldered by this Hot Reflow process.\nWe then remove the PCB from the Hotplate to cool down all componenets and board surface.\nStep 9: Testing LEDs Continuity\nBecause we are using LEDs here, it's crucial to check whether LEDs are soldered properly or not.", "982" ], [ "Flux Capacitor PCB Badge V3\nIntroduction: Flux Capacitor PCB Badge V3\nHey Everyone what's up!\nSo this is my FLUX CAPACITOR Badge version 3 which is a replica of the actual flux cap which was in back to the future movie.\nI've prepared its V1 a few months ago, back then, it had a couple of Throughole componenets which included the main MCU and Slide Switch, so I switched to all SMD components to make this project easy to assemble.\nLike its previous version, this edition requires 2.6V at 0.0069A which is around 0.017 Watts or 0.000000000017 Gigawatts\nIt uses a CR2032 3V Coin Cell to power or we can use any TYPE C cable connected to a smartphone charger.\nIn these Instructables, I'm gonna show you guys how I prepared this Badge by following a few easy steps.\nLet's get started\nSupplies\nMaterial Required\nthese are the things used in this built-\n* Custom PCB (which was provided by PCBWay)\n* LEDs 06038205S Mosfet IC\n* SMD Tactile Button\n* 10K Resistance 0603\n* M7 Diode\n* Attiny13A SOIC8\n* USB Type C port\n* 1K Resistance 0603\n* Lithium CR2032 Cell SMD Holder\n* Solder paste\n* Arduino as ISP Programmer setup (consist of Arduino Nano or UNO)\nStep 1: Circuit Study\nAbove is the Circuit diagram of V3.\nLet me explain how this setup works.\nIn total there are 12 LEDs divided into Four different parts. Each part contains 3 LEDs connected in parallel, these 3 LEDs are then connected with 8205S N channel Moseft IC. Total 4 of these Mosfet ICs are being used to drive 4 different LED parts. An Attiny13A is being used to drive the gate of 4 Mosfets.", "982" ], [ "I've also added a Push Button on Pin D4 of Attiny to control the state of Mosfets. A Type C Port has also been added to power this setup through any Smartphone Charger.\nTo recreate the Flux Capacitor Animation, I've placed LEDs in a twisted way.\nThe First 3 LEDs that are connected in parallel are placed in the innermost part. then the second 3 LEDs are placed a little bit above the innermost part. The other two layers are placed in a similar fashion.\nBy Turning the Mosfet ON in a sequence starting from inside to outside, we get a chasing pattern similar to Flux Capacitor.\nAlso, you can get this Flux CAP from here -\nhttps://www.tindie.com/products/makerpals/flux-cap...\nStep 2: Getting PCBs From PCBWAY\nAfter Finalizing the PCB, I sent the Gerber data to PCBWAY for samples.\nI choose White Soldermask for this project with a Black silkscreen.\nI've added graphics on Both sides of PCB to increase the aesthetic of PCB, Quality of the PCB I received was just awesome.\nI have Been using their service for a while and I have to say, it's pretty decent for getting started.\nCheckout PCBWAY from here- https://www.pcbway.com/\nStep 3: PCB ASSEMBLY\nThese are the steps for the main assembly of the FLUX CAP V3 PCB.\n* Solder paste Dispensing Process\n* Pick & Place Process\n* Hotplate Reflow\nBecause this PCB Doesn't have any Through-hole component, we dont have to add any component with soldering iron, except for the Coin Cell holder on the backside.\nStep 4: SOLDER PASTE\nThe first step is to add solder paste to each components pad one by one.\nTo Apply solder paste, I'm using a Solderpaste Dispensing Needle with a Wide syringe, and the solder paste I'm using is a regular solder paste consisting of 63% Tin 37% Lead.\nStep 5: PICK & PLACE PROCESS\nAfter carefully applying Solderpaste we move on to the next step which is to add componenets to their assigned location.\nI used an ESD Tweezer to place each component in its place.\nStep 6: HOTPLATE REFLOW\nAfter the \"Pick & Place Process\", I carefully lifted the whole circuit board and place it on my DIY SMT Hotplate.\nI made this Hotplate especially for making projects like these which require SMD soldering. hotplate available in the market were not exactly cheap so I made a minimal version of that which you can check out from here-\nhttps://www.instructables.com/DIY-SMT-Hotplate-Pro...", "472" ], [ "PCB Heart Necklace\nIntroduction: PCB Heart Necklace\nHey Everyone what's up!\nSo this is my Heart Themed PCB Necklace. The idea here was to make a necklace from PCB that glows. The concept that I used for making this Necklace was pretty simple as well.\nIt's basically a blinky board consisting of 36 LEDs that are controlled by an Attiny84.\nSupplies\nFollowing are the materials used in this built-\n* Attiny84\n* LEDs 0603 package\n* 10K 0603 Resistor\n* SMD Button\n* Slide switch\n* Custom PCB\n* Arduino nano\n* Coin Cell holder\n* solder paste\nStep 1: GETTING STARTED\nI first searched for a heart image that would be suitable for adding leds and componenets, I select this image in the end.\nI first imported this image on fusion360 and sketched the exposed white lines. then I used the extrude function to make this 2D Sketch into a 3D shape. now we have a 3D Heart shape that will act as a base for our PCB design,\nmy plan is to convert this 3D shape into a drawing and export the top layer's DXF file so my OrCAD PCB suite can import this DXF file which will be then used to make the PCB Outline and art patterns.\nStep 2: Circuit Study\nNow after finalizing the shape, I prepared the schematic which consists of a total of 36 LEDs, 6 LEDs are in parallel and there is a total of 6 different led setups driven by 6 different 8205S N channels MOSFET IC.\nThis Mosfet IC is then controlled by an Attiny84 MCU, we can change the LED Glow pattern by pressing this button.", "982" ], [ "After following the schematic and making a PCB Board with these components, I sent the Gerber data to PCBWAY for samples.\nStep 3: Getting PCBs From PCBWAY\nI received the PCBs in a week which was really fast.\nI choose RED Soldermask for this project with a white silkscreen. I've Left openings in the soldermask on both sides so the LED would be visible from the topside.\nThe quality of the PCB I received was just awesome.\nI have Been using their service for a while and I have to say, it's pretty decent for getting started. Checkout PCBWAY from here- https://www.pcbway.com/\nStep 4: PCB ASSEMBLY\nThese are the steps for the main assembly of the FLUX CAP V3 PCB.\n* Solder paste Dispensing Process\n* Pick & Place Process\n* Hotplate Reflow\nBecause this PCB Doesn't have any Through-hole component, we dont have to add any component with soldering iron, except for the Coin Cell holder on the backside.\nStep 5: SOLDER PASTE\nThe first step is to add solder paste to each components pad one by one.\nTo Apply solder paste, I'm using a Solderpaste Dispensing Needle with a Wide syringe, and the solder paste I'm using is a regular solder paste consisting of 63% Tin 37% Lead.\nStep 6: PICK & PLACE PROCESS\nAfter carefully applying Solderpaste we move on to the next step which is to add componenets to their assigned location.\nI used an ESD Tweezer to place each component in its place.\nStep 7: HOTPLATE REFLOW\nAfter the \"Pick & Place Process\", I carefully lifted the whole circuit board and place it on my DIY SMT Hotplate.\nI made this Hotplate especially for making projects like these which require SMD soldering. hotplate available in the market were not exactly cheap so I made a minimal version of that which you can check out from here-\nhttps://www.instructables.com/DIY-SMT-Hotplate-Pro...\nthe hotplate heats the PCB from below up to the solder paste melting temp, as soon as the PCB reaches that temp, solder paste melts and all the components get soldered to their pads.\nWe carefully lift this PCB and try not to shake it as the solder paste is still melted and components might move a bit from their location if shake the circuit too much.\nwe lift the PCB and then place it on a cooler surface for a little bit, to cool down the heat of PCB.\nStep 8: LED Placement\nNow here's something odd, my plan is to add leds on the bottom side of the PCB but the orientation of the LED would be inverted. which means I'm gonna add them upside down so their glow will be visible from the top.\n* To accomplish this method, I have added 1206 Pads on the PCB and I'm using 0805 Package LEDs with this 1206 PAD, by using smaller LEDs, soldering them would be much easier.", "472" ], [ "Naruto Themed Night Lamp\nIntroduction: Naruto Themed Night Lamp\nHey guys what's up.\nHere's something cool, a <PERSON>-themed Desk light that is made mainly from PCB. The heart of this project is an Attiy13A that drives some 0603 LEDs which are on the backside of the Face.\nThe Head part is detachable or swappable, which means we can prepare two or more Naruto Heads and add different color LEDs on the backside, then we can swap them for whatever light color we need.\nI've modeled <PERSON>'s face in my PCBCad software and then send it to PCBway for samples.\nAfter receiving the PCBs, I assembled the whole board and then added code to it and that is pretty much how I made this project.\nIn this Instructables, I'm gonna show you guys how I prepared this project in few easy ways.\nso let's get started!\nSupplies\n* Custom PCB\n* Attiny13A\n* 10K Resistor\n* AO3400 Mosfet\n* LEDs 0603\n* switch\n* USB Port\n* 3D Printed Parts\n* Li-ion cell\n* Arduino as ISP Setup\nStep 1: Basic Idea\nSo the idea here was to make a Naruto-Themed PCB Art kinda stuff.\nTo make this setup somewhat useful, I added LEDs on the backside so we can turn them ON whenever we like to use this setup as a dope Night Lamp.", "982" ], [ "As for its working, Attiny13A is being used as the main MCU here.\nAttiny13 Controls the gate of mosfet which turns ON or OFF LEDs.\nThe state of Mosfet is changed by pressing the button in a sequence.\n* The first tap will put the setup in a FADE Sequence\n* The second tap will keep this setup in HIGH Mode\n* The third tap will reduce the Brightness by 50%\n* The fourth tap will turn OFF the setup\nNow let's talk about the PCB Designing process of this board.\nStep 2: PCB Design Process\nSo as you can see here, this PCB is not exactly normal.\nThe shape of this PCB is pretty different than the traditional Square or circular PCBs. At the TOP side, the Head is there and this rectangular part is the Driver board that will hold the head and keep the other components like MCU, USB Socket, Switch on it.\nAlso, this PCB is a breakaway PCB, which means we have to separate the Head portion and Base portion from each other by cutting this section with a cutter.\nStep 3: SCHEMATIC\nI placed all the LEDs with the Mosfet setup and a CON3 Header on the head.\nOn Base, I placed all the Important stuff like Attiny13A, USB Port Switch, and a CON3 Header pin. The plan here is to add Male and female Header Pins on both of the CON3 Pin.\nBy doing this, we can now remove or place the head on the base without any permanent solder joint.\nThis idea is pretty cool as we can now model a bunch of stuff from different movies or anime, we just need to place LEDs on them with a mosfet setup and when we connect them to base, they will work.\nAfter finalizing the schematic and then making a perfect PCB, I send the Gerber data to a PCB Manufacturer for samples.\nStep 4: Getting PCBs From PCBWAY\nI uploaded the Gerber data to the PCBWAY's quote page, I wanted to do something different this time so I choose the yellow solder mask, I generally get PCBs in white solder masks but this time I choose a yellow one as naruto hair is Yellow so getting yellow solder mask makes a lot more sense.\nI received PCBs in a week and the overall PCB quality was great, which was expected as PCBWAY always offers quality stuff,\nI've been using their PCB service for a year now, and my review of them is still the same, quality of PCBs is always high which is a plus point.\nPCBWAY, well done you guys!\nCheck out PCBWAY for getting great PCB service at a less cost.\nStep 5: Assembly Process\nNext is the Assembly process of this Badge, which includes -\n* solder paste dispensing process\n* pick & place process\n* hotplate reflow\n* and THT components.\nThere is a total of 2 PCBs in this project and both have SMD and THT components.\nFirst is the solder paste dispensing process\nStep 6: Solder Paste\nFirst, we place solder paste on each components pad, I'm using a generic solder paste (SN-Pb Ratio 63-37) with a solder paste dispensing syringe.\nwe first added the solder paste to the head and then on the base PCB.", "472" ], [ "Bi Flasher With and Without Microcontroller\nIntroduction: Bi Flasher With and Without Microcontroller\nHey Everyone Whazzup!\nSo you want to make a PCB Badge and in that badge, you want to add a simple Two LED Flasher circuit in which Two LEDs will turn HIGH and LOW simultaneously.\nThis task can be done quite easily with or without a microcontroller.\nUsing a Microcontroller is good but for such a minimal task, a timer ic could also be used here which would save a lot of costs.\nIn this Instructables, I'm gonna show you guys how you can use a Microcontroller (Arduino Nano and Attiny13A) and a simple Timer IC Setup to make a Bi Flasher with minimal stuff and Low cost.\nLet's get started\nSupplies\nI will use two types of setups in this project so the following are stuff required in both setups.\nMicrocontroller Setup\n* Attiny13A\n* LED Red and Green\n* Power Source (can be anything, coin cell, 3.7V battery, Bench Power supply)\n* Arduino as ISP Programmer setup\n* Breadboard\n* jumper wires etc\n555 Timer IC Setup\n* 555 Timer IC\n* LED Red and Green\n* 22uf Capacitor\n* Power Source (can be anything, coin cell, 3.7V battery, Bench Power supply)\n* 68k ohms 1/W Resistor\n* 1K Ohms 1/W Resistors\nStep 1: Procuring Materials\nAs for the Source from where I get most of these components, I got the Timer ICs, Attiny13, LEDs, Resistors, and capacitors from ALLCHIPS.\nALLCHIPS is a well-known Platform For Electronic Components Supply, they have everything that you need for any type of project. They are an all-in-one procurement department of hardware manufacturers as all components I used in this project were provided by ALLCHIPS which was a cool and helpful thing!\nAlso, they have this BOM IN ONE BOX thing which is such a helpful thing, we provide them a BOM List and they procure all the components and deliver them \"IN ONE BOX\" which is an efficient way of purchasing components for any project!\nCheck out ALLCHIPS for more info.\nStep 2: Getting Started\nBefore Setting up both versions of a Bi Flasher circuit, let first see where and how we can use Bi Flasher setup.\nI've been making some PCB Badges recently, these PCB Badges are a combination of Art and Electronics in which we add some artistic elements on a PCB like a character from anime or movie or just a few patterns.", "982" ], [ "we also add LEDs on these badges to illuminate certain aspects of that added character or pattern.\nFor example, I made a C3PO PCB Badge from Starwars.\nI've placed LEDs in his eyes and to control these LEDs, I have used the Bi-Flasher setup which is based on 555 timer IC in the SOIC package.\nWhat I'm trying to say here is, this LED Flashing-Blinking setup increases the impact of the whole Circuit and it also looks pretty awesome. If you want to see the whole Badge making process, check this post of mine-\nhttps://www.instructables.com/Obito-Uchiha-PCB-Bad...\nStep 3: Microcontroller Setup\nLet's first start with the easiest method in the Book which is to utilize a microcontroller to control LEDs.\nThe first choice here would be an Arduino board connected with two or more LEDs. This one is by far the easiest set up to make such projects.\nWire the LEDs with Arduino Nano in this way.\n* D3 to VCC of GREEN LED\n* D2 to VCC of RED LED\n* GND of Both LEDs to GND of Arduino\nStep 4: ​Here's the Code for Chasing/Bi Flashing of Two LEDs.", "854" ], [ "Garrison Regiment PCB Badge From Attack on Titan\nIntroduction: Garrison Regiment PCB Badge From Attack on Titan\nHey Everyone what's up!\nSo this is my Garrison Regiment-themed PCB Badge from Attack on titan. Garrison Regiment is one of the three Regiments in attack on titan anime that protects and maintains order within the Walls.\nThe goal for making this badge was simple, I wanted to make some kind of AOT-inspired project that I could keep in my Project collection.\nI also prepared two more Badges from AOT which were themed after the other two remaining divisions which are scouts and military police.\nhttps://www.instructables.com/Wings-of-Freedom-PCB...\nhttps://www.instructables.com/Attack-on-Titan-Mili...\nSupplies\nThese were the things I used in this Badge Project-\n* Custom PCB (which was provided by PCBWAY)\n* Resistor 10K 0603 Package x 1\n* Resistor 2R 1206 Package x 1\n* Attiny13A SOIC8 x 1\n* SMD LEDs 0603 Package x 15 (Color will be RED)\n* Arduino for Programming the Attiny13A\n* Solder paste\n* Coin Cell holder\n* CR2032 Coin cell\n* Slide switch\n* Hotplate reflow\nStep 1: Why Choose PCB, Why Not 3D Printing?\nMy reason for choosing PCBs as a base for this project was also pretty simple if we are making some kind of illuminating device that is meant to be a wearable thing, Using a 3D Printed body with electronics adds too much weight to the whole project and its easier to lay down everything on a PCB and use it as a whole thing instead of making an enclosure for it.\nStep 2: PCB Designing Process and Schematic\nTo prepare this Garrison badge, I first had to find a black and white image of the badge and then convert it from any format into BMP.\nBMP because I will be using my OrCad PCB Suite which only imports images in BMP format, so after converting the image into BMP, I uploaded it into my Cad suite as a TOP Silkscreen layer.\nNow what I want to do here is, I will be adding a few 0603 package LEDs from the backside to illuminate the rose shape in front.\nTo transfer the Glow of LEDs from the backside to the front side, I used one of my classic tricks which are to remove solder mask from the top and bottom side and solder LEDs in an inverted position so their glow will face the FR4 board, we can see the glow from the Front side.\nStep 3: Soldermask Opening\nTo do that, I had to manually fill each area of the Rose pattern which is on the front side with an irregular shape of Soldermask Top openings.\nI did the same on Soldermask Bottom but instead of making the Soldermask Openings of each rose area, I made a huge opening as this side won't be visible from the Top, we are making this opening to let the light from LEDs get past the FR4 Board.", "982" ], [ "By doing this, we will be able to see illuminated Rose from the front side without adding any components on TOP Side.\nStep 4: SCHEMATIC\nTo Drive all the 15 LEDs, I use an N Channel SMD Mosfet which is AO3400, its gate is connected with an Attny13A.\nWe use the Attiny13 to control the gate of mosfet to fade or blink the LEDs.\nthe schematic of this project is attached above.\nStep 5: Additional Stuff\nI've made this designed in such a way that if we dont want to add any Blink or fade sequence through using Attiny, we can skip the MCU and Mosfet by shorting R6 and this will connect LEDs directly with the Coin Cell holder.\nBy Shorting R7, we can connect this setup with Attiny and mosfet.\nI believe badge projects should be simple as possible so anyone can make them on their first try which is the whole point of making this project. Adding Functions like glow and fade or multiple LEDs will increase the aesthetics more but using an ESP12F or Higher MCU for a simple blinky board seems very overkill. An Attiny85 can be used here as an Alternative as Attiny13A isn't powerful enough for driving RGB Neopixel LEDs.\nStep 6: Getting PCBs From PCBWAY\nAfter Finalizing the PCB, I sent the Gerber data to PCBWAY for samples.\nI choose RED Soldermask for this project, this was my first time getting RED soldermask PCB from PCBWAY and the quality of PCBs was just great.\nBeen using their service for a while and I have to say, it's pretty decent for getting started.", "472" ], [ "DIY Studio Light/ Light Box\nIntroduction: DIY Studio Light/ Light Box\nHey Everyone what's up.\nThis is my DIY Studio Light Project\nWhich basically is a do-it-yourself studio light that is made from a custom 3D Printed body and a custom PCB which were both provided by PCBWay.\nQuestion\nIs it better to Buy an expensive Studio Light or Make your own DIY Studio Light with custom 3D Printed parts and PCB?\nWell, the goal for making this project was just that, I wanted to make a DIY Studio Light for my current \"Maker Setup\" as the lighting in my lab bench is not very great.\nCommercially available light costs above 50$ (good ones) but why spend money on them when you can make your own Studio Light, Body can be made from a 3D Printer and the circuit can be manufactured by a PCB manufacturer.\nIn this Instructables, I'm gonna show you guys how I made this DIY Studio Light in few easy steps.\nLet's Get started!\nSupplies\nThese are the things that I used for this built\n* LEDs (NICHIA JK3030 3V .2W LED)\n* 1.5 Ohms Resistance 1206 Package\n* 0.47 Ohms Resistance 1206 Package\n* 100uf Capacitor\n* 63uH Indictor\n* SS34 Diode SMA\n* DC Barrel Jack\n* Custom PCB (which was provided by PCBWAY)\n* Custom 3D Printed body (which was also provided by PCBWAY)\n* SIC9301A led driver IC x2\n* 12V DC FAN (Generic small one)\n* 12V SMPS Power Supply\nStep 1: Basic Structure\nMy goal was to make a DIY Studio Light completely from scratch to compete with existing light available in the market.\nThe reason for starting this project was the cost of the existing setup, Commercial Studio Light isn't exactly cheap and I need at least 2-3 Lights which would cost a lot so I made an easy-to-make Studio Light with custom PCB and 3D Printed Body.\nAlso, I'm using a generic FR4 PCB here. these LEDs produce a lot of heat so why I'm not using MCPCB (metalcore) instead of FR4 (fiberglass) for making a better-LED PCB that can disperse heat better than FR4 Board?\nYou see, I have added lots and lots of Via in this PCB, these Via will conduct heat from the top side and transfer that heat to the bottom portion which will result in Heat getting Disperse equally. Then at the backside, there's a 12V Mini DC FAN which cools down the PCB heat.\nApparently, Metal PCBs or MCPCBs are not $$$ wallet-friendly and if I have used a metal PCB in this project, I also have to use another FR4 board for LED Driver IC setup.", "982" ], [ "So I saved a lot by making a single PCB that contains the LEDs and Driver IC setup.\nAlso, the Body of this light is made from PET-G which is quite a durable plastic so overall, this DIY Studio Light can sustain heat.\nStep 2: Schematic\nThe main schematic of this project is attached above and as you can see, it's not very complex. it contains two LED Driver IC setups both with their LOAD (LEDs) connected separately.\nTheir Input side is connected with each other which is the common Input VCC and GND. we will supply 12V to these two terminals to run this board.\n(yes, I haven't used any Microcontroller or any Switching IC in this Circuit)\nStep 3: PCB Designing\nWith the above Schematic, I prepared the PCB in my CAD software.\nThe board outlines were already designed in the Fusion360, I used its measurements as a reference to make the PCB.\nI placed LEDs at the center of the board and maintained an equal distance between them, to keep things symmetrically accurate.\nAnd as you can see, I've placed lots of Vias in this PCB. Vias cover almost 70% of this PCB and they are here for Conducting heat as well as connecting one side with another side of the board.\nAnyways, after finishing the PCB, I exported its Gerber data and send it to PCBWay for samples.\nI Received the PCB in 7 days which is pretty fast, and it also came with a PCB Scale which was pretty cool (I have used my beans to get that scale though)\nI have to say, PCBs that I've received were great as expected, PCBWay, you guys rocks.\nCheck out PCBWay for getting great PCB Service for less cost!\nNext is the PCB Assembly Process.", "472" ] ]

[ 3777, 3418, 6924, 2015, 9002, 1435, 11117, 11072, 9346, 8890, 9138, 731, 5679, 4110, 10564, 4293, 4397, 5711, 8337, 9095, 4639, 1126, 3547, 5182, 2178, 7616, 1693, 5505, 6205, 5361, 1716, 9869, 9428, 3296, 2193, 5744, 9155, 9953, 755, 8767, 2430, 1968, 6554, 5132, 9057, 1784, 10951, 5389, 5216, 9743, 101, 8965, 9817, 10886, 375, 8000, 6546, 6089, 9886, 5232, 5579, 11320, 4718, 2198, 3574, 989, 350, 6236, 9070, 631 ]

[ [ "Black Panther: Wakanda Forever\nMCU Films Ranked\nDefinitely one of the stronger projects to come out of the MCU in a while. It focuses on a contained story that doesn’t require you to watch all the tv shows to understand it. It builds off of the first film well while also respectfully saying goodbye to <PERSON>.\n<PERSON> is a fantastic villain who really adds to the intensity of the film and <PERSON> performance is top tier. Also the cringy MCU humour is at a minimum which is always appreciated.\nOverall it’s a solid film but it definitely is lacking in originality and adds very little to the MCU.\nThe ending is absolutely beautiful.\nGrade: 74%", "647" ], [ "The Good Nurse\n2022 Films Ranked\nI understand that I may have enjoyed this film more than the average viewer due to me being an absolute sucker for crime dramas/thrillers, but wow, this film was a fun watch.\nMaybe “fun” isn’t a good word to use. This is an extremely disturbing film that tells a horrifying true story, but it’s a story that is so captivating and unnerving that it had me on the edge of my seat from the opening shot.\n<PERSON> and <PERSON> absolutely kill their performances, but <PERSON> in particular blew me away.", "241" ], [ "He shows such incredible range throughout this film and proved once again how good of an actor he actually is.\nIf you don’t know the details of the crime this film is based around I suggest not doing research prior and to just go into the film blind. There is something so riveting about finding out the details with the characters as the movie goes along.\nOne of the most entertaining and unsettling films of the year. It doesn’t reinvent the wheel by any means, but with the great acting, fascinating story and solid execution, this is overall a really good movie.\nAnyone who loves a good crime movie like myself, check this one out.\nGrade: 83%", "583" ], [ "The Menu\n2022 Films Ranked\nA captivating and highly original critique on “The Elite” 1% and their presence within modern society.\nThe Menu is a really well executed dark comedy with elements of horror. It’s a somewhat satirical dissection on pretentiousness and what it means to truly be an “artist.” This film was super entertaining from start to finish and though it was slightly predictable the storyline was one that felt very fresh and original.\n<PERSON> leads this talented ensemble with a heartfelt but unnerving performance that is truly incredible. He, to a certain extent, carries this film through his acting, and helps to make even the slow parts enjoyable and memorable.\nThe food is stunning. Truly some of the most beautiful dishes I’ve ever seen presented on screen.", "241" ], [ "Whether it’s a miniature edible ocean ecosystem or a simple cheeseburger, the food was gorgeous.\nPersonally, I didn’t love the ending. It was fine, but for some reason it just didn’t hit me as hard as I think it should have. It honestly just felt like a mediocre recreation of Midsommar that lacked the shock value and artistic flare.\nIt’s a solid film that has a great message. It’s also executed well and is really entertaining. It’s not a perfect movie by any means and it doesn’t really try anything new from a filmmaking perspective, but if you are into dark comedies or have a passion for the culinary arts, you’ll definitely enjoy this one.\nGrade: 74%", "596" ], [ "The <PERSON> of Inisherin\n2022 Films Ranked\nThis is most likely going to be the last film I watch in 2022 and honestly, this was a great film to end the year on.\nThe In Bruges boys are back at it again but this time with a film that is less laugh out loud funny but instead one that is far more mature, simple, and heartbreaking.\nIt’s a <PERSON> film so it is still very witty and darkly comedic, but this does feel like his most down to earth and “dramatic” film to date. Though I don’t think it is quite on the level of genius as Three Billboards Outside Ebbing Missouri, there is something so simplistic and unpretentious about this film that makes it such a refreshing watch.\nBeautifully shot with mesmerizing locations, and great performances from the entire ensemble. Though Everything Everywhere All at Once is still my favourite film of the year, I would not be mad one bit if this film started picking up some best picture or best screenplay awards.\nThis hit really close to home for me and was weirdly very relatable to certain things currently happening in my life. Because of that I actually found myself getting quite emotional while watching this.\nA great movie and another amazing addition into <PERSON>’s filmography.\nGrade: 92%", "905" ], [ "Spider-Man: Across the Spider-Verse\nThis… this right here is art.\nThis Spider-verse trilogy is going to be up there for one of the greatest trilogies of all time. This film was absolutely phenomenal, even though the vast majority of it is purely just set up for the next film. Every frame is stunning and the attention to detail is something rarely seen in films like this today.\nA brilliant film that’s just as good, if not better than the first, and I have a hunch that the third one is going to be even better than both of them.\nGrade: 90%", "462" ], [ "The Suicide Squad\nYes! This is how you do a Suicide Squad movie!\n<PERSON> not only delivers a great DC movie, but also a fresh take on the super hero genre.\nFrom the first scene you know that there are stakes. As the marketing already made very clear, no one is safe. This adds a lot of tension to the movie, you never know which fall or bullet will be fatal.\nThere's so much to talk about. The cast is great, featuring some standout actors, but they work so good together.", "796" ], [ "Like <PERSON> constant rivalry with <PERSON>'s character, which leads to one of the greatest action scenes.\n<PERSON> as <PERSON> is again very good, maybe even at her best in this one.\nThe story, unlike the first one, feels more like something the Suicide Squad would tackle. A covert operation in a hostile country, is the perfect setting for this team. The story takes some twists and turns to at the end wrap it up with an amazing final battle.\nTalking about battles, <PERSON> knows how to get the most out of it's R rating.\nMaybe my only negative I can think of is that <PERSON>'s Thinker is kind off wasted.\nBut except that I had a lot of fun! I sat at the edge of my seat during the whole runtime. Laughing and gasping at everything that happened.\nIf this is the direction the DCEU is going in, count me in!", "577" ], [ "Marriage Story\nAfter hearing all the hype for this movie, I went in expecting a masterpiece. Watching Marriage Story, I quickly realized this isn’t the same kind of masterpiece that Parasite is. It’s a masterpiece because the story, acting and cinematography is entirely human and real. The long takes, the superb acting, and the pensive atmosphere creates masterful story telling. I watched this not wanting it to end.\n<PERSON> creates scenes that if it were another movie would seem too long, but here fit perfectly and still keep your attention. <PERSON> & <PERSON> give their best performances ever.", "217" ], [ "This is a new standard of filmmaking. One that is more human, cutting out the fluff of current Hollywood. The score is incredible too. The tone is set the first ten minutes thanks to the beautiful score.\nThe only problem is, I wish this was shown in theaters nationwide. To start and stop this movie, as one does with Netflix, is a disservice to the movie as whole.\nOverall this movie is perfection. 5 stars.", "583" ], [ "Poor Things\nBeing a big fan of <PERSON> this was my most anticipated film of the year and I’m beyond satisfied to state this film lives up to the hype.\n‘Poor Things’ is a film like absolutely nothing I’ve seen before. The originality is completely off the charts and I loved everything I saw.\nThe film touched on themes of growth, sexual liberation, freedom, identity, lower vs higher class and power. So much passion in this project you just can’t help but adore this.\nFrom black and white to gorgeous vibrant colours, the cinematography was visually striking. The set design was also stunning and played a huge part in the personality of the film.\nI’m not sure why it’s not labelled as a comedy because the whole cinema was in laughter many times. The screenplay was impressive, definitely the best I’ve heard this year. The sharp deliveries and snappy, hilarious one-liners really added to the enjoyment of this wild film. It’s absurd and bizarre but also so relatable in many ways.\n<PERSON> will be picking up her second Oscar for Best Actress. She immerses herself into her role impeccably.", "217" ], [ "She really went above and beyond all the limits to accurately portray the character <PERSON> was seeking out - they make an incredible duo. <PERSON> & <PERSON> were also fantastic in every scene.\nMy only slight criticism is the film loses its rhythm slightly around the two-hour mark. It almost stalls and includes some in my opinion unnecessary scenes. But this is a very minor criticism. Because the vast majority of the film was brilliant.\nWhenever <PERSON> intended to be funny the cinema was laughing, when he wanted it to be serious it was meaningful, anything he directed into through that lens translated to the audience perfectly. I can see myself coming back to this multiple times in the future. It’s got all the elements of a future classic. Like <PERSON> or not? It doesn’t matter you’ll have a blast.", "132" ] ]

[ 6532, 9850, 7384, 1601, 234, 9581, 2879, 59, 922, 7909, 7976, 1057, 2213, 7341, 8047, 1566, 1312, 4118, 8075, 9830, 5755, 2901, 2301, 9774, 1056, 8704, 2381, 6345, 4256, 9422, 9187, 5661, 8679, 3056, 629, 8258, 507, 5460, 5982, 3044, 10055, 7256, 9352, 8765, 1907, 1141, 8371, 1900, 2447, 10615, 2391, 769, 8446, 9271, 8448, 9430, 3937, 11134, 1552, 10772, 7655, 5585, 7677, 8859, 4498, 2307, 5081, 9019, 10536, 3098 ]

[ [ "<PERSON>\nI can see why a lot of fans love this one. It's a grand, operatic, melodramatic trilogy capper that puts a lot of focus on <PERSON> and <PERSON>. But... I just don't connect with it. It's one of the meanest movies I've ever seen, and I don't think it fully earns that moniker, thanks to haphazard dialogue and plotting. It's just a hard, grisly watch.", "698" ], [ "And that ending - there's too much going on! That's before the next few movies add even more layers to it. Anyway time for the praise. There is an artistry to the bleakness, and I think there's more to the themes and story than most of the other Saw movies. The acting is actually pretty good too. A mixed bag.\nI am not doing a full Saw rewatch btw. I just wanted to get refreshed on the original trilogy before Saw X. Building that hype you know", "596" ], [ "The Silence of the Lambs\n1000 Spines #13\nFeels so good to finally revisit this after like six years. Such a joyous watch from start to finish. Makes me feel so disgusting. Love love love the structure of it. The forward framing is so cool.", "291" ], [ "<PERSON>'s presence (and lack of presence) throughout the film is fab, and honestly I could say the same for <PERSON>. Really interesting how little <PERSON> is even in the film. But he's serving when he is. <PERSON> is just such a delight. Let's go lesbians! Honestly excited to continue watching the Hannibal trilogy, although I have no idea what I'm getting myself into.", "577" ], [ "<PERSON>\nThe first half of this is so good. The second half, I think was difficult for the filmmakers to make sense out of (and how can you make sense of senseless tragedy? I’m not sure, but that is why we create art, in the end).\nThe chemistry between the brothers and how they all were suffocating under the pressure from their father was done so well.", "306" ], [ "But when tragedy strikes, it devolves into scene after scene of unfortunate events that feel isolated and without much meaning. <PERSON> character is great, but the other brothers don’t get nearly enough fleshing out to fully appreciate their arcs. That said, I understand it’s a delicate balance because it’s a true story.\nThe tail end brings it home, though.", "352" ], [ "Killers of the Flower Moon\nFrequently fantastic, bold, sweeping, and bloated. <PERSON> crafts a handsome and classical drama that explores a very real historical atrocity. The choice to focus on the perpetrators of the crimes is an intriguing one that mostly works, specifically in how it shows how one can lie to themselves to justify their horrific actions, and the corrupting power of greed. But it also means we miss out a lot of the point of view of the <PERSON>.", "217" ], [ "I understand that Scorcese may not be the best choice to tell that side, but while watching I felt like we were missing an integral part of the story. There's clearly an effort to be as respectful as possible, though, and I appreciate the conversations this film will spark. It's not just a one-and-done. It's dense as hell, and I'm glad I got to catch this in a cinema.", "596" ], [ "Thanksgiving\nI wanted to like this more than I did. I love slashers but there's a few aspects here that I feel like distract a tad and work against each other. One being I'm waiting around for the movie to recreate scenes from a trailer I saw 16 years ago. That creates a sort of auto pilot.", "596" ], [ "Another thing is the huge plot points hinging on social media and live streaming that feels so against the grain of that Grindhouse trailer. Plus adding in a Black Friday stampede feels more 16 years ago then now. So I kinda found this to be all over the place. That said, I'd absolutely watch a sequel because we need more slashers in this world.", "269" ], [ "Anatomy of a Fall\nI get why this is a Palme d'Or and why fans are falling over themselves lavishing praise on the movie. I do get it. It's great. The script is exceptional, the world (which was a mystery to me - The French courtroom I mean) is engaging and the performances wonderful.\nAnd I give it 4/5.\nIt just never hit me in the chest as hard as it seem to have for everyone else.", "462" ], [ "It never twisted up my mind or enraptured me with it's storytelling. It's an extremely well crafted movie and I'm having just as much fun with the after-discussions and \"theories\" on the plot as I did watching the film. I just never got that \"wow\" factor. Wish I had.", "596" ], [ "The Last Man on Earth\nCrazy about the first 20 minutes of <PERSON> just going about a \"normal\" post-apocalyptic day. Also really love the way this mushes together zombie and vampire iconography - not something I've seen before.", "475" ], [ "The rest of the movie is good but it has a certain level of self-seriousness that I just don't think I'm in the mood for. Was probably ruined by seeing and really enjoying The Omega Man first, in which <PERSON> makes <PERSON> look like a paragon of restraint and subtlety. Hard to go back to the comparatively respectable version once you've gotten attached to that.", "698" ], [ "Signs\nMy most notable Letterboxd review is a pan of Close Encounters. <PERSON>, who loves <PERSON> as we all do, wanted this to be his version of it. I think this one is way better.\nA broken man in an impossible situation relearns how to love and protect his family. <PERSON> crushed it with two great kid actors. Compared to a movie like Independence Day, this is basically a home invasion film.", "369" ], [ "It didn't have to be aliens, it could have been anything (except for the thematic reasons). <PERSON> is a tortured man just barely holding it together, which in retrospect turned out to not be a stretch for him. <PERSON> really didn't need to cast himself as the manslaughtering neighbor. Weirdly for a movie about an atheist preacher mourning his dead wife, this is kind of his funniest movie. It's really pretty cheesy but it works for me unlike Close Encounters.\nAlso, the shared memory people my age have of that footage of the birthday party being one of the most terrifying things in cinema is some sort of fever dream we all had. It's a tense moment but stop citing it as one of the scariest movie moments of all time.", "698" ] ]

[ 11202, 7943, 1976, 10879, 135, 6799, 1280, 4426, 713, 4304, 7784, 3020, 2487, 885, 3072, 3802, 562, 8731, 7990, 6829, 114, 3808, 3730, 11170, 3008, 4242, 727, 4498, 8052, 2068, 2365, 3599, 8470, 7278, 3364, 9162, 3766, 10653, 7898, 3914, 10850, 7218, 11245, 514, 9571, 6200, 3604, 9642, 1651, 2164, 2347, 4756, 3902, 8329, 92, 9313, 829, 9726, 1794, 5314, 10934, 6657, 3233, 10719, 7973, 2005, 1663, 9054, 2684, 9667 ]

[ [ "You seem to want or need to have a person single-handedly responsible for the shift from heavier-than-air flight to lighter-than-air flight.\nI'd like to suggest an alternative approach which may give you the result you require.\nBack in the 1970s there was a some fairly serious talk in some circles about a possible resurgence in the popularity of blimps and dirigibles for long-distance travel. The reason? The Energy Crisis which began in October of 1973.\nCurrently we are undergoing a climate crisis based off the use of fossil fuels, and oil-based energy continues to become more expensive as we continue to burn through irreplaceable reserves.\nAdditionally, consider that while airborne transportation is very popular with over 100,000 flights worldwide per day, it seems to be increasingly difficult to turn a consistent profit from year to year in that industry. Wikipedia lists 83 airlines, since 1979, which have gone out of business, re-organized as another business, or have merged with a larger airline.\nYou'd have to work out the timeline, but I would suggest a future where it is simply too expensive for most commercial endeavors to employ heavier-than-air flight in their daily operations. One man has seen the writing on the wall and has positioned his considerable wealth into the re-development of dirigible and blimp technology. During the crash of oil reserves his gamble pays off and he's now the leader of some dirigible monopoly.\nDirigibles would now occupy the place of the ocean-going liners of the late 19th and early 20th century as the primary mode of international transport. A 1930s dirigible crossing of the Atlantic took from 3 to 4.5 days, depending on weather and routing and such; I would suggest that with modern technology and knowledge of atmospherics one could probably guarantee a crossing in either direction in 2-3 days.\nAn envelope calculation figures that it would take about 1.16x10^12 cubic feet of helium to carry the same amount of cargo as a supermax vessel, so you may want to consider a similar, parallel, ocean-going sail industry! It currently takes a cargo vessel 9 or 10 days to cross the Atlantic -- sometimes as long as 20 days, depending on the actual destination. My own limited experience with ocean-going sailing makes me believe that a modern cargo vessel with the best sail technology would take a good month to cross the Atlantic. So: maybe the majority of cargo is moved around via ocean-going sailing vessels, but you'd still have some class of super-dirigible for carrying cargo more quickly.\nHelium without an oil-based economy is an interesting problem. We don't have a lot of helium in the atmosphere because it's so light; it floats to the top of the atmosphere and is blown off by the solar wind.", "308" ], [ "My understanding is that we get most of our helium from the oil industry. So if you want your dirigibles to be elevated by helium, you're going to have to find a source.\nI would suggest a world which uses fusion energy. It's a source of energy which would be only economically feasible for city-scale power production, but which produces helium as a \"waste\" product. Now you have a cheap source of helium. But, fusion power would be too expensive, not to mention too bulky, to power even a very large cargo vessel, much less an aircraft.\nNow, while hydrogen has proven historically to be a bad choice as the lifting gas for dirigibles, I would suggest that is only true using 1930s technology. Using modern technology and materials the use of hydrogen as a lifting gas would arguably be much safer, with the added benefit that you can use it as a fuel for propelling the dirigible. So, if it's a story you're writing, or an RPG milieu, you may want to use hydrogen as the lifting gas to introduce some kind of balance or limiting feature in your world, especially if you really don't want to use fusion technology.\nAnd the use of dirigibles would not preclude the use of fossil fuels in other areas. The military, of course, would continue to use fossil fuels in nearly all their aircraft. Private and government aircraft would probably use jets powered by liquefied hydrogen.\nThose are my thoughts on this interesting question. Hope that helps.", "435" ], [ "The origins of the words \"port\" and \"starboard\" may be useful to consider here. Early ships did not have a rudder built into the hull, but instead used a modified oar - or later, a larger and more sophisticated steering-board - positioned at the helmsman's right hand. To prevent damage to these devices, the opposite side of the ship had to be moored to the wharf, hence \"port side\" and \"steer board side\". A certain amount of lexical drift resulted in \"starboard\" for the latter.\nThe practical upshot is that port and starboard are synonyms for left and right respectively in the direction of travel. So they only make sense for a vessel which has reasonably consistent \"forward\" and \"up\" vectors.\nThe ISS, even though it is a space station existing in microgravity, is such a vessel:\nNominally, the ISS flies in an LVLH (Local Vertical Local Horizontal) attitude. That means that the vehicle pitches at four-degrees-per-minute in order to keep its belly pointed towards the Earth. So, nominally, the orientation of the ISS appears rather consistent with respect to the Earth.\nThis is desired because the vehicle was designed to be in an attitude in which the comm antennae pointed up at the TDRSS, the GPS antennae point up at the GPS satellites, the thickest shielding is in the direction of greatest debris damage risk, the windows point towards Earth for Earth observation science, and other external payloads can point at their desired topic, consistently.\n<PERSON>, NASA\nHowever, this would not be true of a wheel-type or cylinder-type rotating space station, whose gyroscopic properties would keep it pointed along a consistent axis instead of in \"local attitude\" - unless the axis of rotation happened to be aligned with the plane of orbit.", "947" ], [ "That would actually be a reasonable orientation for a wheel-type station, but not for an O'Neill cylinder which must keep its axis pointed towards the local sun.\nA far more reasonable organisation for both types would be compass directions. As seen from above the North Pole, the Earth rotates anticlockwise, resulting in the Sun appearing to rise in the East. Analogous definitions result in natural N/S/E/W directions in a rotating wheel or cylinder. Up and down would be reversed relative to a rotating planet (ie. up is inwards), due to the direction of apparent gravity.\nNote however that a common design for <PERSON> cylinders is as a pair, rotating in opposite directions, so that the common axis can be precessed to follow the sun through its orbit. In such a design, north and south would be at opposite ends in each cylinder, so would not be useful for locating external non-rotating parts of the station (though residents probably wouldn't care). In such cases, an additional set of directions based on the \"hot\" and \"cold\" ends may prove helpful.", "15" ], [ "Sounds like you're in the market for a brand new torch ship! Step right this way...\nhttp://www.projectrho.com/public_html/rocket/torchships.php\n<PERSON>'s site goes over various definitions for a torch ship, but it boils down to any rocket which has both high thrust and high specific impulse (fuel economy). In general this means getting away from chemical rockets and moving over to rockets which use some kind of nuclear reaction.\nOnes we might be able to build in the near future are mainly based on fission - Orion drives and nuclear salt water rockets. These are every bit the radiological hazard you might expect them to be, so you wouldn't want to operate them in a planet's atmosphere. Not one that you cared about, anyway.\nMore speculative versions are based on fusion. Some of these (deuterium-tritium rockets, for instance) are still pretty dirty. Others (proton-boron and proton-proton) are much cleaner, but you still wouldn't want to be anywhere near the exhaust when the engine was running.\nNaturally, the cleaner reactions are much harder to initiate and sustain than the dirtier, more neutronic ones. Thanks, universe.\nAll of these have the potential to get you to a closer planet like Mars in pretty short order. The exact amount of time will depend on how much delta-V your ship's engine and fuel fraction gives you, but think in terms of days instead of months.\nThis has a lot of advantages.", "199" ], [ "For one thing, shorter trips mean less radiation exposure for passengers and crew. Engines that aren't as mass-limited mean that you can push more cargo and carry more shielding. The spacecraft is reusable, which keeps costs-per-trip down. You can reach the asteroid belt in only a little more time than it would take to reach Mars, so you can potentially extract raw materials from there to maintain your space effort, instead of having to lift them out of a gravity well.\nIt's not all roses though.\nIf you're using an engine with a highly radioactive exhaust, you'll probably only want to use it in space. That means that you'll need a more conventional way to escape Earth's gravity well to get to your interplanetary craft.\nFortunately, that falls into the realm of reusable rockets (now not actually science fiction any more) and spaceplanes. Check out the Wikipedia page for SpaceX for a breakdown of their current and future reusable launch vehicles, or Skylon for an idea of how a spaceplane might operate.\nProject Rho is a veritable gold mine of engine ideas, as well as in-depth discussions on any other facet of spacecraft design you can think of. All of it's are based in real physics, too. Scroll down to the bottom of the page for a full list of subject areas.\nEverything listed represents a significant engineering challenge, but none of it is physically impossible.", "199" ], [ "You can make it believable\nAs a writer you get to make a few assumptions about the environment in which your story happens. Clearly you're not intending to write a futuristic Sci-Fi novel in which humanity has already colonized the galaxy; the question makes it clear that humanity is still earth-bound.\nBut how earth-bound is humankind's technology? To make the basic story work (single person escaping Earth and settling elsewhere), there must be plenty of accessible resources in the Solar System. And here in 2019, those resources are not yet accessible. They exist - there's plenty of evidence of ice on the moon for instance. They're just not at all useful.\nBut what we do have in 2019 is robotic space exploration. It turns out robots are the better pioneers, they survive much harder environments. So what if we assume a few decades of slow development towards space mining? Your much-improved AI explains why robots are still preferred over humans in space, and they have a basic off-Earth infrastructure running for basic chemicals such as water, hydrogen, oxygen, steel, etc.", "199" ], [ "Mars can have a robot base with a nuclear reactor in this scenario. But of course, no habitat for humans yet.\nNo space agencies You didn't exactly say what you meant by \"no space agencies\". But this is another case where you get to choose what it means, as long as you can make the story believable. So you can just say that the organizations ceased to function as the vast majority of personnel became ill or died, and basic society collapsed so the remaining personnel was no longer funded by the state. But as space mining required a fairly steady pace of launches, this process had been automated to a much larger degree to keep costs down.\nPerhaps SpaceX now has rockets that launch and land from underground silo's, where the rockets are resupplied by robots between missions. And without anyone deciding to launch new missions, all rockets have returned to their home silo's and are waiting for orders. Unbelievable? Well, it's the only way in which mining titanium in space could be made profitable, in your story.", "199" ], [ "Yes and no.\nSome stages of progress are inevitable. For instance:\n1. You don't use tools at all.\n2. You make tools from things which are just lying about, like sticks and stones for weapons or lumps of clay for a cup.\n3. You figure out that flint is a better stone for tools than quartzite is, so you starting digging flint out of the ground. Hurrah, you've invented mining.\n4. You figure out that clay heated in a fire is harder and lasts longer than the sun-dried stuff. Hurrah, you've invented pottery.\nOn the other hand, the environment of your alien species is going to be a big factor. Dolphins and octopuses, for instance, are never going to invent pottery, because they live underwater and thus can't do the simplest version (firing pots in a bonfire) to kickstart that whole line of technology.\nSo anywhere the chemistry doesn't or can't work the way ours does will not be able to duplicate some of our achievements (fire won't burn underwater). Or they may discover something earlier in their development, For instance fires burn hotter and longer in high oxygen atmospheres, so observing what heat does to things may be a higher priority for them, and they invent smelting or kilns quicker than we did.\nThe environment includes the other creatures you share the planet with. If you have no equivalent of cattle and horses, you don't invent the plough, the stagecoach or horse-drawn artillery.", "335" ], [ "Animal power was a major factor in many of Earth's civilisations and technological developments.\nNext, there is the anatomy and physiology of your aliens themselves. For instance, if they have wings and can fly (and obey the laws of physics), they will be severely restricted in how much they can carry and still take off. A bird-alien can't cover itself in chainmail or platemail unless it wants to be stuck on the ground. Bird-aliens may therefore neglect aspects of metallurgy in favour of trying to create tough but light textiles to act as armour.\nIf they are carnivores, they are not going to invent horticulture or arable farming early like we did. They'll probably invent pastoralism (herding animals) pretty quickly, but it may be a long time before they decide to start growing fodder for their domestic animals.\nAnd if they are not growing plants in their equivalent of the Stone Age, then they are not going to kickstart a whole bunch of other industries - anything which relies on plant fibres or plant oils, for instance. So they might invent knitting, wool weaving and felt making because they keep sheep, but they won't have canvas for sailcloth & tents or linen for clothes, because they never grew flax for edible seeds and oil and thus never figured out its other properties.\nFinally, their psychology. If they are a truly territorial species, by which mean territoriality in the biological sense of the word they don't travel and they don't invent trade. They stick within their territory boundaries and react with violence when strangers turn up. Territories are small, globally speaking. A territory might be the size of farm or small national park, but it is never going to be the size of a country. The aliens can't invent any technological development which relies on resources outside their territory. So they can't have a bronze age unless they've got both copper and tin on their particular patch of land.", "197" ], [ "Anything is possible. This post assumes an Earth-like technology with basically just space-enabled technology. So space-missiles, space-ships, space-mines, etc.\nPossible the most effective way to attack an Alcubierre drive ship is to attack it's end point. The Wikipedia article taking about the Alcubierre drive talks about how to travel at very fast speeds using it, you need to begin the process of that travel as many years before as the destination is lightyears away.\n<PERSON> and <PERSON> comment that <PERSON>'s finding \"does not mean that <PERSON> bubbles, if it were possible to create them, could not be used as a means of superluminal travel. It only means that the actions required to change the metric and create the bubble must be taken beforehand by some observer whose forward light cone contains the entire trajectory of the bubble.\" For example, if one wanted to travel to Deneb (2,600 light years away) and arrive less than 2,600 years in the future according to external clocks, it would be required that someone had already begun work on warping the space from Earth to Deneb at least 2,600 years ago, in which case \"A spaceship appropriately located with respect to the bubble trajectory could then choose to enter the bubble, rather like a passenger catching a passing trolley car, and thus make the superluminal journey.\"\nSo if one knew where the ship would end up, one could set-up an attack on the destination.\nOne could also send a projectile into \"the bubble.\" The missile will then either hit the ship during travel or immediately after it arrives.", "947" ], [ "This would not prevent a ship from arriving, necessarily, but it would likely prevent it from doing anything.\nThis rest of this post assumes that the \"bubble\" of space-time created by the Alcubierre-drive does not push all space away from it, so that only the space \"native\" (i.e. in the bubble when it was created) ever actually enters the bubble. If this is the case, sabotage would be required to attack an Alcubierre-drive ship in-flight.\nThe most effective way to attack/defend a moving Alcubierre-drive ship would be a mine that attached to the ship. An Alcubierre-drive still requires the ship to pass over all the space it travels through, it just does so at a very fast rate.\nAnother way is to send a projectile into path of \"the bubble\" (see quote above) that the ship will be traveling through. It would have to travel along the same route of the ship, but in the opposite direction, because estimation of an <PERSON> ship's position would be difficult to impossible.\nWikipedia says that the above to methods could work, because\nA paper by <PERSON> published in 2002 argues that crew members could not control, steer or stop the ship because the ship could not send signals to the front of the bubble.\nSo even if they knew the mine was in their path while in the bubble, they could do nothing to prevent the inevitable explosion. This might result in the sending out of \"dummy ships\" to blow up mines and missiles before the main, expensive ship comes.", "947" ], [ "No, not in the way these \"grav lifts/antigrav lifts\" are depicted in the literature.\nSurprisingly, this has nothing to do with (anti-)gravity.\nA typical scenario would be: you return from lunch, enter the mgea-skyscraper at ground level, step into an \"antigrav tube\" and move up to your office on the 240th floor, where you and your lunch arrive, quite possibly, separately.\nThe idea of this kind of life was perhaps inspired by a paternoster lift (https://en.wikipedia.org/wiki/Paternoster_lift), and movement in the lift tube is usually described just like that of paternoster lift, just without cabins.\nNow, with constant and human-manageable velocity (the passenger enters and exits the lift on his/her own, by means of a handle), this trip will take some time (let's say 15 minutes for single 240 floor trip). Basically, when you arrive at ground level, you can immediate embark on the return trip to your office because the travel time leaves no time for lunch. Which saves you from the embarrassing situation of you and your lunch arriving separately.\nObviously, one \"solution\" would be to have constant acceleration (and deceleration) in the grav lift. So, on the trip from your 240th floor office to ground level, you would accelerate for the first half the trip and decelerate for the second half. Mathematically, with about 1 g-force of acceleration, you could expect to arrive in maybe 20 seconds. Practically, you will crash into Guido from the 120th floor after 10 seconds, at a speed of 350km/h.", "947" ], [ "Lunch separation issues are now the least of your worries.\nAgain, this is about how the lifts are depicted in the science fiction literature. You might add accelerator tubes which bring the passenger up to some fixed travel speed before entering the main tube, and some clever exit system which pulls the passenger out of the main tube upon arrival at the pre-selected destination and slows them down in a separate decelerator tube. But that's far from being as \"elegantly simple\" as the grav lifts depicted in the literature.\nAnother solution would be to \"bundle\" passenger with similar trips (this is actually done in real life right now, to increase the bandwidth of conventional lifts). You might even provide cabins for these \"passenger bundles\" (groups).\nOh, wait. That's too much like a boring ordinary lift. Note that in very tall building, even the boring ordinary lift already accelerate (and decelerate) at 0.5 g-force - and this is already a bit of a lunch containment issue for some people.", "947" ], [ "Interstellar combat without instant FTL\nIn this scenario there are two spacefaring empires, each with a handful of solar systems under their control. The two empires have been adversaries for millennia.\nIn each solar system there are habitable worlds. Any indigenous population on these worlds was forcibly conscripted into the empire that found them first and operate as a vassal state. Unoccupied worlds were populated.\nThe technology in this scenario allows for planet-to-planet travel in a matter of hours. Imagine 1 hour from Earth to Mars, or 10 hours from Earth to Uranus for scale, something akin to air travel for us now.\nSystem to system travel, while faster than light, still takes centuries. Neighboring systems might be 200 years, while the frontier systems may take 800 years or more to reach from the core worlds. Most of the beings in this universe have a life span similar to humans - assuming technological advancement in health care and gene-therapy, maybe 200 years. Cryogenic suspension is possible but difficult.\nThe question is: What does this war look like?\nSending a fleet to assault a system would take hundreds of years and several generations, and would be seen coming decades before they arrive. Also, those ships would be unavailable to counter some other offensive launched against their civilization.\nI have a few options on the table already:\n* Attaching drives to meteors or other large space rocks and launching towards the expected location of the system. These could travel faster than the ships, maybe decades instead of centuries. I assume these species could to the math for where to aim them.\n* Ships full of robots, again these could go faster than 'squishy' ships.", "302" ], [ "They would be hard pressed to accommodate changing commands though.\n* Ships with no crew but full of bio-weapons.\nNote: For the sake of the story, let's assume communication is near-instant across systems.\nThanks!\nUpdate:\nJust to provide some clarification, each side of this war has a deep-seated, almost religious belief that their empire must be the one to control the stars. There's nothing political about the war, it simply must happen, and must continue until one side wins.\nSecond, neither side wants to rule over a galaxy of glass balls in space. They know that habitable planets and populations are valuable. Each side wants to conquer the systems while still having something to rule. Since all but the original system for each empire was forcibly conquered in the first place, a change of allegiance is realistic. (Perhaps several systems have been passed back and forth already)\nThey would be willing to 'nuke' a planet or two if necessary, but for the most part the goal is to take control of the planets under the other empire's control.\nThe 'vassal state' planets are effectively doing their own thing in terms of society, but they are directed by the overlords to help the war effort - for example 'attack planet x' or 'build shipyards'.\nUpdate 2\nFirst of all, thanks everyone for the feedback and ideas. It's a lot to wade through and there a lot of ways this could impact the universe I'm thinking of, I'm going to need to unpack it all in my brain.\nSecond, I need to apologize because I muddied the question by referencing FTL. My intention was to ask what a war would look like without planet to planet travel times being short, like in Star Trek or Star Wars. Going back to my old math / notes, the speed I'm looking at for ships is about 10% of Light speed, or around 1,000,000km/h.\nAt this speed, Earth to Mars would be less than an hour, Earth to Uranus about 25 hours, and Earth to Alpha Centauri would be 42 years, Earth to Wolf1061 would be 140 years, etc... Not accounting for acceleration issues, if there are any with this level of technology. I want it to be somewhat science-based but a little handwavium is OK to keep the story entertaining (it will use real star systems and their real distances for example, but somehow maybe the aliens all have a universal translator).\nThird I think technology of the two main factions would basically have plateaued. The vassal planets might not all have an even level of technology, but overall there aren't any game changing discoveries that change the balance of power on a regular basis any more.", "302" ] ]

[ 628, 4561, 9737, 6932, 7201, 13, 10081, 6779, 5851, 10888, 2594, 9032, 8304, 5910, 7840, 5839, 7406, 4844, 10515, 8326, 7780, 3011, 7858, 4589, 2446, 6187, 6900, 6288, 1385, 7042, 5432, 4150, 1753, 8683, 4951, 5420, 10727, 3783, 2016, 836, 4904, 4586, 4787, 529, 3969, 6471, 5311, 7631, 9039, 8449, 7587, 10459, 10830, 3769, 273, 7401, 2256, 10046, 1069, 4276, 496, 6757, 11350, 1085, 10999, 8438, 3856, 3113, 10258, 4833 ]

[ [ "How to Mill Rough Lumber With No Jointer\nIntroduction: How to Mill Rough Lumber With No Jointer\nwww.howidothingsdiy.com\nIn this video I'm going to show you how I mill rough lumber with no jointer. As you may have noticed, I don't have a jointer but I also want to start using nicer types of wood like walnut from local lumber yards. So I have to mill the lumber with the tools that I have. With rises lumber prices, you can also save money by milling cheaper cuts of lumber.\nThe first thing I need to do is mill the first face flat. I do this by making a planer sled and supporting the piece of wood, then running it though the planer.\nThe next step is to mill the other side so it is parallel to the first side and even thickness.\nNext I have to cut one straight perpendicular edge. Ordinarily I would do this with my jointer jig for my DeWalt table saw, but it is not long enough for this board. So I screwed a straight piece of MDF to it for a straight edge.\nFinally, I simple run it though the table saw with the new straight edge against the fence to get the last edge.\nBeat those rising lumber prices and save money on wood. Subscribe for more videos like this.\nSupplies\n-Planer\n-Table Saw\n-Drill\n-3/4\" MDF\n-CA Glue\nStep 1: Cut to Rough Length\nIt makes it much easier to work with the piece of wood if you cut it a little over the length you need it to be for your project. I needed a 60\" piece of wood so I'm rough cutting my piece to 65\"\nWhen rough cutting the wood to size, its is a good opportunity to identify any imperfections you do not want on the ends. and try to cut those off when doing your rough cut.\nI marked the board and then cut it in my miter saw.\nStep 2: Make Planer Sled\nPlanning the board by itself will create a face that is parallel to the other side including any warps or cupping.\nIf you want a flat face, you will need to make a planer sled. I made a long planer sled for this piece out of 3/4\" MDF. The sled needs to be longer than the piece of wood you're working with. I made mine 66\" x 10\". and then added a strip of wood to one end as a stop. The stop is just attached with CA glue.\nStep 3: Mount and Support Board on Sled\nLay the board on your new sled and identify any areas that are not touching the sled.", "431" ], [ "Now, using shims and hot glue, support all the voids. Also add a little more glue around the board so it doesn't move when going through the planer. The board should not rock or move after this step.\nStep 4: Plane First Face\nStart passing your board though the planer. Take off small amounts until their are no more rough areas left.\nStep 5: Plane Second Face\nNow remove the board from the sled. Using a flat surface, confirm that the board is now flat. Then flip it over and plane the other side until you have reached the desired thickness. If you are not using it right away, you can leave it a little thick. This allows you to do the final milling just before you use it to get rid of any imperfections that may have occurred while storing.\nStep 6: Create a Straight Edge\nLay the board on your bench \"bad\" side up. Find a straight piece of wood (I used MDF) and position it on the board so it hangs just slightly over one of the edges. Now screw it in place. Be careful not to put screws through areas of the board that will be visible on your project.\nNow, using your attached board as a fence guide, run it through your table saw. Be careful to only remove enough material to clean up the edge. Taking too much off is just wasteful, taking off too little will not give you a straight edge.\nYou can also use a table saw taper/jointer jig for this step. I have one that is 48\" long so it would not work for a board this long.\nStep 7: Cut Last Edge\nNow remove the guide board and run it though the table saw again. This time use your new straight edge cut in the previous step as your fence guide. Again, remove just enough to fully clean up the final edge.\nIf done correctly, you should now have a board that has two flat, parallel faces and two perpendicular and parallels edges.\nEnjoy making your project with your freshly milled piece of lumber!", "76" ], [ "Dino Charcuterie Board\nIntroduction: Dino Charcuterie Board\nIn this woodworking shorts video, I'm making a charcuterie board for kids. A charcuterie board is a decorative board meant for holding meat, cheese and fruit. I'm using walnut wood along with a piece of hard maple wood. I'll walk you through the process on how to make a charcuterie board. I used a Ridgid jigsaw to cut out the dino shape, but a scroll saw probably should have been a better choice. I also used my DeWalt DWE7491 table saw and my DeWalt DW735 planer for most of this project and then I finished up the board with a round over and mineral oil.\nCharcuterie boards make great gives as well. This dino charcuterie board was a gift for my 6 year old son. He loves dinosaurs, meat and cheese.\nAmazon Links (helps support my channel, thank you!)\nMineral oil- https://amzn.to/3HhFQuj\nTitebond 3- https://amzn.to/3FDF8qV\nWelcome to How I Do Things DIY! Subscribe for more videos like this!\nSupplies\n-Wood of your choice\n-Wood glue\nStep 1: Charcuterie Board Layout\nPick an animal or shape you want to use for your board. Be sure it has enough area to lay out some meat and cheese. Place some meat cheese and crackers on a piece of paper and sketch your shape around it. You may need to tape a few pieces of paper together or use larger paper.\nStep 2: Rough Cutting Boards\nMy final board is 3/4\" thick with 1\" wide pieces of wood. I used walnut and hard maple. Decide how you would like the wood on your board and then rough cut the pieces and lay them over your stencil. Be sure the entire stencil is covered with wood. Then cut out your stencil and lay it on top of the wood just to make sure you have enough wood cut.", "493" ], [ "Leave the boards about 1/8\" thicker than they need to be so you can take them down to final width when planning the board.\nNote: Make sure the board you made can fit through your planer or drum sander.\nStep 3: Glue Up\nNow put several lines through the laid out boards to mark their position. Now flip them on their side and spread out the wood glue. Be sure to use food safe wood glue and to spread evenly to the entire face of the boards. Now flip them back and clamp them up with good even pressure. Its a good idea to use cauls to keep your board as flat as possible. Let the board dry for 24 hours. Then remove the clamps and scrap off any excess dried glue.\nStep 4: Planning Board\nNow run the board through the planner or drum sander to make it smooth and to take it down to its final thickness.\nStep 5: Cut Out Shape\nTrace the stencil onto the board. Then used either a jigsaw or a scroll saw to cut out the shape.\nStep 6: Sanding\nSand the edges and the face from 40-120 grit sand paper. You may want to used a paint stirring stick with sand paper on it to get the details around the edge.\nStep 7: Adding Round Over\nNow, use a router and add a round over. The size of the round over is personal preference. Hand sand any imperfections left from the router with 120 grit sand paper.\nStep 8: Water Pop\nWater pop the board by spraying or soaking in water. Then allow to completely dry before proceeding to the next step.\nWater popping with cause the grain to stand up, leaving the board rough. This will allow you to sand that rough grain off. This will allow your board to stay smoother even after washing.\nStep 9: Finish Sanding/oil\nOnce the board is completely dry, finish sand to 220 grit sand paper. Then apply or soak the board with food grade mineral oil. Once the board has absorbed as much oil as it can, wipe off any excess oil.\nThat's it! Clean your board and throw some meat cheese and crackers on it and surprise you kids with it! I promise they will love it!", "76" ], [ "Scrap Wood End Grain Cutting Board\nIntroduction: Scrap Wood End Grain Cutting Board\nIn this woodworking video I'm using scrap wood to make a scrap wood end grain cutting board. This how-to woodworking video will show you step by step how to make a DIY cutting board. I'm using walnut scrap wood along with a piece of hard maple wood. End grain cutting boards are the best because and the most expensive because of the extra steps required as well as their durability over their life. I used my DeWalt Table saw and my DeWalt planer for most of this project and then I finished up the board with a juice groove, which I make a juice groove jig for, and mineral oil.\nSupplies\n-Whatever scrap hardwood you have laying around!\n-Titebond 3 wood glue (https://amzn.to/3CiMcI5)\n-Mineral Oil (https://amzn.to/3joeNnU)\n-Cove box router bits (https://amzn.to/3m4NjFC)\nStep 1: Plane to Consistent Thickness\nPlane all boards down to 3/4\" thick.\nStep 2: Rip Into 1 5/8\" Strips\nThen rip all boards into 1 5/8\" wide strips.\nStep 3: First Glue Up\nNow glue up in the desired pattern as shown. Be sure to use glue that is waterproof and rated for use with food. I used Titebond 3.\nStep 4: Plane to 1 1/2\" Thick\nAllow the glue to to dry to 24 hrs and then plane down to 1 1/2\" thick.\nStep 5: Cut Into 1 5/8\" Strips\nNow, using a cross cut sled, cut into 1 5/8\" wide strips.\nStep 6: Second Glue Up\nNow, flip every other piece to randomize the pattern and glue up as shown. Be sure to use lots of clamps for even pressure.\nStep 7: Plane to Final Thickness\nNow, plane to the final thickness of 1 1/2\" thick. When planning an end grain board be sure to remove very small amounts of wood on each pass so you do not separate the grain or cause tear out.\nWARNING: It's very dangerous to do this in a planer. It's possible for pieces to break off and shoot out of the machine at high speed. If you follow my instructions, attach longer sacrificial pieces of wood to the long edges with masking tape and CA glue.", "76" ], [ "This will help protect the ends as well as prevent snipe.\nStep 8: Clean Up Edges\nNow clean up all 4 sides of the board. Start by using masking tape and CA glue to create a straight edge on one of the long edges as shown. Then clean up the other long side on the table saw. Finally, clean up the short edges on the table saw using a cross cut sled.\nStep 9: Add Chamfer\nIf you would like to, add a chamfered or roundover edge using a router.\nStep 10: Cut Juice Groove\nCreate a juice groove jig using the link below. Then, carefully, cut the groove in multiple passes. The direction of the router rotation should push the router into the guide jig.\nStep 11: Final Sanding\nNow sand going through all the grits but stop at 120. Then wet the board and let it dry. This will cause the grain to \"pop\" allowing for you to sand it smooth with 120 and 240 grit. This will also keep the board smooth over time.\nStep 12: Add Rubber Feet\nIf you would like to add rubber feet, pre drill small holes in all 4 corners about 1\" from the edges. Now screw on the feet.\nStep 13: Oil\nFinally, fill a plastic bin with food grade mineral oil and let the board soak for 30 min. Remove the board, wipe off excess oil and allow time to dry before use.", "76" ], [ "How to Make Drawer Boxes | With a Beveled Face\nIntroduction: How to Make Drawer Boxes | With a Beveled Face\nwww.howidothingsdiy.com\nIn this woodworking video I'm going to show you how to make drawer boxes with a floating bottom and how to install them. This drawer is a little special as it has a beveled front face. I'll walk you through all the steps to build this walnut drawer box with a floating bottom. I'll show you how to install drawer slides and make adjustments. I'll even show you a trick to install the drawer face.\nThis drawer build is part of building a walnut office desk. Please also check out the rest of the build on my channel.\nSupplies\n-Drawer slides\n-3/4\" Wood for frame\n-Wood glue\n-Brad nailer\n-1/4\" plywood for floating bottom\n-Scrap 3/4\" plywood for nailiers\n-1/2\" plywood for supports\nStep 1: Install Supports to Attach Slides\nFirst measure your space and select and purchase right slides. If the area you want to install your drawer into doesn't have anything to attach slides to, add some supports to screw to. I used 1/2\" plywood for the supports and 3/4\" plywood to make some mounting blocks to nail to. I used CA glue to immediately hold the piece in place while I nailed it but also regular wood glue to hold the support in place long term. Then I glued and nailed some 3/4\" support blocks in place for added strength.\nStep 2: Measure and Cut Frame\nMeasure your space for the drawer between the supports to determine how big your drawer box can be. Just remember that typical drawer slides are about 1/2\" wide on both sides and that you will need to attach a face to the front of the drawer. Now cut the sides, front and back. I'm using 3/8\" rabbets in the side pieces so I added 3/4\" to the front and back. Remember, you want to build the frame with the front and back inside of the side pieces so only the sides are visible when the drawer is done. You do not what to have end grain showing.\nStep 3: Cut Floating Bottom Slot in Frame\nCut a slot about 1/4\" from the bottom of each of the frame pieces. Not find a scrap piece of wood and do the same.", "401" ], [ "Now move the fence enough to make a slot just wide enough for the drawer bottom and try it on the scrap piece. You should be able to slide the drawer bottom in the slot but it should fit snug enough that it wont rattle. Once your happy with your test piece, cut all of your frame pieces the same way.\nStep 4: Cut Rabbets in Side Frame Pieces\nUsing either a dado set or multiple passed with a flat kerf blade, make your desired rabbet cut so the front and back frame pieces fit into the sides. Again, I made my rabbets 3/8\" deep and as wide as the material I was using.\nStep 5: Assembly/Cut Bottom to Size\nAssemble the back and side pieces using the rabbet cuts, glue and brad nails. Measure and cut the bottom to fit into the slots with about 1/8\" of allowable movement. Now slide the bottom into the frame and then install the front frame piece using the rabbet cuts, glue and brad nails. Fill the holes and rough sand the assembly. You will be sanding it again later.\nStep 6: Install Slides\nTypically side mounted slides will be mounted near or at the bottom of the box. But in this example I mounted them near the top because of the beveled front face. I attached the slides to the drawer box first and then measured where the mounting holes needed to be in the supports on the desk. Then I predrill holes and installed the slides in the desk, making sure that they were level. Then, test fit the drawer box into the the space and make sure it slides smoothly. We will make final adjustments later.\nNote: If the drawer is a little tight you can plane or sand down the side faces a little bit to get the drawer to slide smoother.\nStep 7: Sand/finish\nMake sure all the holes are filled and then sand working your way from 60-240 grit sand paper. Finish with your finish of choice.\nStep 8: Install Face\nUsing double sided tape, stick the face in place where you want it. I added recessed holes for the face screws on the inside, but it is not necessary. Screw the face on from the back side making sure the screws you selected will not go through the front of the face. Now remove the drawer and double sided tape and reinstall using the screw reference holes you just made.", "785" ], [ "How to Make a Wooden Box Joint Box\nIntroduction: How to Make a Wooden Box Joint Box\nwww.howidothingsdiy.com\nIn this video I'm going to show you how to make a wooden box with box joints. However, there is a twist. Most boxes use hinges or a sliding lid, this box opens in a unique way you won't usually see. But you’re going to need to watch the video to see what that is!\nI’ll show you how to cut the frame, cut box joints, use wood glue to glue the frame together, build the top and bottom assembly and finally, apply finish.\nMost of the work was done on my DeWalt table saw with the help of my box joint jig and my cross cut sled. Links below.\nSubscribe for more videos like this!\nTools\nTable saw w/ box joint jig and cross cut sled (videos to build them on my channel)\nDrill and drill bits\nRouter\nOrbital Sander\n<PERSON> nailer\nDado blade set\nSupplies\n1x6 pine board\nWood Glue\nWood filler\n<PERSON> nails\nStep 1: Cut Frame to Size\nDecide how big you want to make your box and cut the1x6 pieces to size.\nStep 2: Cut Box Joints\nInstall your dado set and get out your box joint jig. Now cut all your box joints in all four frame pieces.\nStep 3: Dry Fit Frame\nAssemble the frame with no glue just to make sure all the joints are cut properly.\nStep 4: Make Corner Supports\nNow reinstall your standard table saw blade and cut 4 corner pieces to keep the box square but also to stop the lid mechanism when fully opened and closed.\nStep 5: Assemble Frame\nApply glue to the box joint ends making sure to get glue on all edges of the joints. Now assemble the box together. Make sure everything is fully seated and square. Now clamp in the corner pieces. Use a scrap piece of the lid material to space the supports from the top.", "493" ], [ "The supports should hold the lid flush with the top of the frame.\nStep 6: Build Top/bottom Assembly\nCut top and bottom pieces that fit nicely but but still slide freely. Now cut two pieces for either side of the box that connect the top on bottom. They will need to be narrow enough to fit in between the corner pieces install earlier. Test fit all pieces.\nNow drill a finger hole in the top piece. I used a 1\" forstner bit. Now glue and brad nail the components so when they are assembled, the top/bottom assembly can slide up and down to open the box. The top and bottom should be flush with the frame and the assembly should stop in the opened and closed position on the corner pieces.\nSink all brad nails just below the surface.\nStep 7: Apply Finishing\nFill all small holes with wood filler. Then sand with 80, 120 and 220 grit sand paper until its all perfectly smooth. Finally, wax the entire box and the mechanism with paste wax. Test for smooth operation.\nIf you like this concept but want a different size box, you can scale it up and down.\nEnjoy your cool little box for storing small things.", "56" ], [ "Easy Box Joint Jig | Quick Box Joints in Your Table Saw\nIntroduction: Easy Box Joint Jig | Quick Box Joints in Your Table Saw\nwww.howidothingsdiy.com\nIn this video, I'll show you how to make an easy box joint jig. You will be able to make quick box joints in your table saw. I'll show you how to DIY and the make box joints. I'll cover making the slides for the miter slots, making the base, using CA glue and screw to attach the base, making the frame, attaching the fence, creating an indexing pin and waxing the slides and base.\nPlease SUBSCRIBE to my YouTube channel for more great how-to videos!\nDownloadable plan available for purchase here:\nhttps://howidothingsdiy.com/plans/ols/products/box...\nSupplies\n-Dado Set https://amzn.to/3oTbRmM\n-Hardwood or poly table saw slides\n-1/2\" plywood\n-1x4 pine lumber\n-1x2 pine lumber\n-Short wood screws\n-Paste wax https://amzn.to/3oSMvFE\nStep 1: Step 1: Cut Slides to Size\nMake the slide out of a hard wear resistant wood. Cut to fit without slop and be just proud of the saw table.\nStep 2: Step 2: Cut Base to Size\nI used 1/2\" birch plywood cut to 12\"x16\". You could also use 3/4\" or make a difference size for your needs.\nStep 3: Step 3: Attach Slides to Base\nUse CA glue and accelerator to glue the slide on. Then remove from the saw and predrill and countersink holes and screw into place.\nStep 4: Step 4: Attach Frame\nI used a 1x2 for the three frame sides. I glued and brad nailed them into place. Cut the fence a little long but do not permanently attach it yet.\nStep 5: Step 5: Install Dado Set\nRemove the blade and install a dado set.\nStep 6: Step 6: Temporarily Install the Fence\nScrew down the fence so you can cut the indexing pin slot.\nStep 7: Step 7: Cut Dado Slot\nThe slot width will be how wide your finished joints are. The depth of the slot should be a little less than the thickness of the wood you will use.", "493" ], [ "I use a 1/2\" dado for 3/4\" thick wood.\nStep 8: Step 8: Cut and Install Indexing Pin\nRemove the fence. Now cut indexing pin material to fit tight in the slot in the fence. I used oak for wear resistance.\nStep 9: Step9: Permanently Install the Fence\nNow install the fence offset from the blade by that distance as the width of the indexing pin. You can use some of your extra indexing pin material to do this. Now permanently glue and screw the fence in place while the slides are still in the miter slots so it doesn't move.\nStep 10: Step 10: Wax the Slides and Base\nNow wax the slides and base to allow the jig to move smoothly on the table.\nStep 11: Step 11: Test!\nTest using a scrap piece. Start with first piece butted up against the indexing pin and work your way over. Not flip that piece over and put it back over the indexing pin as a reference for the mating piece. Work your way across the mating piece until its complete. Test the joint. If it fits properly, you can glue it together to make it permanent.", "599" ], [ "How to Make a Crosscut Sled | Simple Table Saw Sled\nIntroduction: How to Make a Crosscut Sled | Simple Table Saw Sled\nwww.howidothingsdiy.com\nIn this video I’m going to show you how to make a crosscut sled to allow your table saw to make perfectly square cross cuts. This is a simple table saw sled but very functional. It incorporates a Powertec t-track and t- track stop.\nI’ll cover cutting the slides, cutting the base, milling the fences and attaching them. Then I’ll show you how to attach the t-track and stop. Finally, we will cut the slot and wax the slides and base.\nPleas SUBSCRIBE to my YouTube channel for more great how-to videos!\nDownload full PDF plans for this cross-cut sled here:\nhttps://howidothingsdiy.com/printable-pdf-plans/ol...\nSupplies\n1/2\" Birch Plywood\n(1) STRAIGHT 2x4\nWood Glue\nWood Screws\nT-Track and Stop https://amzn.to/30ivomf\nCA glue and activator https://amzn.to/3mG6DYB\nWood wax https://amzn.to/3oVO2dQ\nStep 1: Cut Slides\nRip down your slides so they fit your tracks without play but still slide smoothly. They should be around 1/16\" proud of the table top. I used oak for better wear resistance.\nStep 2: Cut Base\nUsing 1/2\" birch plywood, cut the base to the size you want your sled. The size is your own preference but I chose to make this sled 24\"x18\". You can also used 3/4\" plywood or a different species of wood.\nStep 3: Attach Slides to Base\nPut the slides in the miter slots aligned with the edge of the table. Position the table saw fence so the base is centered on the slides. Mark the location of the slides on the bottom of the base. Now apply a bead of CA glue on the slides and then spray the accelerator on your marks on the base.\nNow butt the base up against the fence and then carefully lay it down on the slides.\nFinally, drill and countersink holes and then screw the slides to the base.", "493" ], [ "Be sure none of the screws are still proud or it will scratch your table saw when in use.\nStep 4: Mill Front and Rear Fence\nMill down all 4 sides of your 2x4's for your front and rear fence. You should only be removing just enough to get full cleanup of the surface. This is to ensure the are smooth and straight.\nStep 5: Drill Holes and Mount Front Fence\nDrill and countersink holes for your front and rear fence. Now glue and screw just the front fence in place, as shown. This fence is only meant to hold the base together after the slot is cut. It does not need to be perfectly square, it just needs to look nice. The rear fence will be attached later.\nStep 6: Cut Slot\nPut the sled on your saw and cut a slot from the front to about 2\" from the back and stop. DO NOT CUT ALL THE WAY THROUGH YET!\nStep 7: Install T-Track in Rear Fence\nMeasure your t-track and cut a dado in the front of the rear fence so, when installed, your t-track is flush. Then mark the hole locations, predrill holes and screw the t-track in place.\nStep 8: Install Rear Fence\nTake extra care with this step! Put down a bead of wood glue where the rear fence will go and set the rear fence in place. Lightly clamp it down. Make sure the rear fence is square with the slot cut earlier in the process. Then you can tighten the clamp and screw down the rear fence.\nStep 9: Wax Slides and Base\nNow, wax the slides and the base with wood wax so it slides smoothly on the table when using.\nStep 10: Test!\nNow test the sled and check your cut to make sure you are making square cuts.\nNow be amazed at what you were able to accomplish and enjoy safer, straighter cross cuts on your table saw!", "76" ], [ "How to Make a Zero Clearance Insert (For Table Saw)\nIntroduction: How to Make a Zero Clearance Insert (For Table Saw)\nwww.howidothingsdiy.com\nIn this video I’m going to show you how to make a zero clearance insert for your Dewalt DWE7491 table saw! Even though this is specifically for the DWE7491, it can be used for many other table saws. Especially other DeWalt table saws.\nI’ll explain why you need a zero clearance insert (safer, better cuts, better dust collection) and then show you how to make it. I’ll cover cutting out the basic shape, zero clearance insert layout, cutting out the tabs, finger hole and adjustment screws so you can level the insert when done. I’ll also show you the safe way to run the blade through your insert.\nNow I can make much safer and cleaner cuts with better dust collection.\nPleas SUBSCRIBE to my YouTube channel for more great how-to videos!\nSupplies\n-1/2\" Plywood\n-Table Saw\n-Sander\n-Drill\n-Jigsaw\n-1/2\" Wood Screws\n-Hacksaw\nStep 1: Cut to Width\nCut the 1/2\" plywood on the table saw to fit in the throat plate slot snug but not tight.\nStep 2: Layout Details\nRemove the hardware from an old factory throat plate and clamp it to your work piece. Now mark out the profile, mounting tabs, adjustment screw location and the finger hole location.\nStep 3: Drill Finger Hole\nUse a fostner bit to drill about a 3/4\" finger hole. Drill part way through on one side and finish the hole on the other side to reduce the risk of tear out.\nStep 4: Cut Out Details\nUse a jigsaw to cut out the radii on the ends and cut around any mounting tabs. Leave about a blades width of extra material to be sanded later to the exact size.\nStep 5: Sand to Final Size\nNow, test fit the part in the slot on the saw and note any areas that need to be sanded. Then carefully sand and test fit until you have the perfect fit.\nStep 6: Install Adjustment Screws\nUsing the marks you made during layout, drill and countersink holes for the adjustment screws.", "493" ], [ "Be sure the holes are slightly smaller than the threads of the screws you plan to use.\nNow screw in the adjustment screws and make sure the heads can sit lower than flush when fully tightened.\nNow cut off the excess with a hack saw.\nStep 7: Cut Clearance Groove\nWith the table saw unplugged and the blade removed, raise the blade adjustment all the way up. Try to install the the new insert and note any areas of interference. If there is interference, cut clearance using a router or whatever other tool you have or makes the most sense.\nStep 8: Run Blade Through Insert\nReinstall the blade but leave the riving knife off and attempt to install the insert. If you can not install the insert because it's hitting the blade, put your old insert in and cut a blade relief groove in the slot just deep enough to allow you to install it.\nOnce are able to install it, clamp a scrap 2x4 over the top of it and then turn your table saw on. Now very slowly raise the blade to the maximum height.\nStep 9: Extend Slot for Riving Knife\nNow, observe the location of the riving knife when the blade is all the way up. Mark out extension lines on your insert to allow the riving knife to clear in the max height position.\nNow, very carefully, cut out the area for the riving knife with your jigsaw. If your insert is very thin after cutting the blade relief groove, you should reinforce the ends of the relief groove before doing this. I cut some pieces of wood on my table saw and glued and clamped them in place.\nStep 10: Sand\nSand all sides of the insert smooth.\nStep 11: Apply Paste Wax\nApply paste wax to protect the insert and also reduce friction.\nStep 12: Final Adjustment\nInstall your insert and use your adjustment screws to get the insert just below flush with the table.\nStep 13: Test\nTurn the saw on and raise the blade to the max height to make sure there are no clearance issues. Then lower it back to a normal level and cut a thin strip of wood to make sure it works as it should.\nEnjoy safer, better cuts with a little less dust!", "76" ] ]

[ 8746, 9300, 4825, 3045, 1117, 11169, 3834, 10400, 2605, 11371, 4773, 1833, 4198, 9460, 7398, 10970, 1288, 5095, 10990, 9563, 6105, 10995, 7286, 3805, 5880, 1542, 775, 7854, 10981, 3740, 2833, 8743, 6755, 354, 2008, 6292, 6849, 1372, 4465, 10060, 10700, 10856, 7595, 205, 4149, 981, 2380, 7538, 33, 11066, 4507, 7727, 3718, 2162, 10340, 2337, 8363, 7012, 5522, 5896, 7807, 2809, 4052, 5195, 10104, 8939, 6343, 9075, 1933, 2865 ]

[ [ "Neru\nA very <PERSON> core movie, in every sense. The presentation, the writing, the 10 secondil 10 reaction shots, the dramatic tone everything is your typical <PERSON> style, which is the movie's ultimate drawback. It could've been an alright movie if he had kept aside his usual antics (keep the transition game tho, those are fun). Everyone in this movie is at the most extreme point of a particular character trait, the evil person gives the most obvious wide evil smirk every time he gets, the opposition lawyer is the most evil inhumane lawyer you will find, stuff like that. All this is done to garner sympathy for the victim but the thing is we already are very sympathetic to the victim, there's no need to reinforce that.", "796" ], [ "Istg they showed or described that rape scene like 6 times, you didn't have to do that we get it.\nActing wise every character is in different zones, <PERSON> is being as evil as he can, vere characters are doing vere random things. The most annoying character in this movie is <PERSON>, its like she wrote herself into the script just to serve as 'ahem I actually know law', like some scene at the court happens which is very clear to the audience. However, still she uses the next 5 minutes to explain what happened as if the audience didn't understand. <PERSON> but <PERSON> aa dramatic performance keri keri engoto pokum. <PERSON> our ashwasam is A10, itu necessarily our great performance alla to be called a comeback but <PERSON>, he has done his role neatly and I am happy with that. <PERSON> i see the light.", "132" ], [ "<PERSON>\nIt's fun, <PERSON> atra <PERSON> onnum toniyilla, sure it has it's issues but at the end I'd say i had fun.\n<PERSON> main issue i feel is like oru tonal inconsistency, oru spaghetti western fight pedakumbo atinte edak goofy auggh pokan lesham padanu. So it leaves the audience wondering how to feel about it and creates this awkward atmosphere, i felt the same for the first 20mins, <PERSON> goofy <PERSON> embrace <PERSON> It's more fun. Like goofy agumbo i like it atepole A10 aa music vechu mass western kanikumbolum i dig. <PERSON> amanushikante kadha kelkana laghavatode kandal its more fun, you'd like to know more about it. Philosophical bagam eniku atraku angidu click ayilla, i can sense it but <PERSON> angidu kathiyilla. Also language accent inconsistency was kinda annoying, <PERSON> typical ljp core vartamanam, should've just stuck to one.", "1010" ], [ "Score and visuals were great, visuals <PERSON> edak i go daymn, atepole score <PERSON> score orma vannu. The fights were kinda cool, slow mo kurakayirunu, would've been more cooler. Also I'm glad to see <PERSON>, like he's probably the only one who could pull this off, he has this aura, but ya pulliyude aa potential ethiyitilla, last aa harish <PERSON> ik if A10 would've done it in his full potential I'd cry, despite the writing being kinda shallow. But at the end I'd say ya fuck <PERSON> anu A10nte we're soo back. Also sad to see LJP fall victim to the sequel idea, please stop making sequels if it isn't very necessary, a plain good old story which concludes itself neatly is beautiful. Shoutout to <PERSON>, she's soo beautiful i think I'm in love with her.\nAlso <PERSON> was hype asf ngl, shonen anime battle vibes, part 2 indakindel i will be there no matter what", "80" ], [ "Scream VI\n\"Film nerds with letterboxd account instead of personalities\" Damn, I feel attacked lol.\nScream VI exceed my expectations, it was a lot better than I expected. The cast are amazingly good, the setting is amazing (especially the shrine), the story line is pretty engaging, and the gore/violence are appatizing. I had a blast since the very first opening scene with the scream queen herself <PERSON> until the very end of the movie. I love the easter eggs and nods to other horror movies, it make the whole movie more meta than ever. I watched Scream VI two times in a row and I think it slowly dethroned Scream IV as my second favourite in the franchise.\n<PERSON> is a fucking gnarly maniac in this one! Very menacing, agile, and disturbingly talkative. There were a lot of really suspenful and intense scenes with <PERSON>, usually they were just clumpsy, goofy, and playful. I love how the mask were looking grimy and rough, reminds me of <PERSON> mask in Halloween 2018.", "444" ], [ "That being said, I kind of see it coming but it was beautifully executed, it was still quite formulaic but felt fresh at the same time.\nI thought <PERSON> was gonna be abrasive little brat at first, but thankfully she didn't. <PERSON> was marvelous as always, the relationship between <PERSON> and <PERSON> also felt more organic this time. I'm happy to see the full potential of <PERSON> as <PERSON>, she's way more interesting and relatable, I think it has a lot to do with how they write her character this time around. All the supporting act was really great too!\nNow you enter the <PERSON> section:\n<PERSON> is by far my favourite character in the franchise, I was really bummed out when they \"killed\" her in Scream IV, but I was so excited when I discovered an Easter egg on Scream V that lead to the fact that <PERSON> is potentially still alive. I smiled so hard when I saw her face, she make the movie ten thousand times better. I actually like the red herring in the third act that suggest she's the killer, I thought that would be insane and bold but I guess they didn't want to go that route.\nOverall, Scream VI was extremely entertaining, there's a lot of nostalgia boost but the movie itself is really good. I purposely watched it after all the hype kinda subside and it was proven that Scream franchise is genuinely fun and everlasting. <PERSON> would be proud.", "444" ], [ "The Conjuring: The Devil Made Me Do It\nAn underwhelming third chapter to An excellent series.\nThe premisse of the film is quite strong and tries to set it apart from the predecessor. Gone is the haunted house and now we're focused on a kid who claims the devil made him kill someone. That's a very great start to a story.\nBut it doesn't quite always work as they expected it too. Resulting in a bit of a mess that unlike it's predecessors isn't really that scary.", "133" ], [ "It's not that i got used to the scarrs, they just weren't that good. The few scary scenes were spread far apart and very much the same.\nThey do play with color more in this one, resulting in a gorgeous movie.\nOf course the warrens again carry this film.\nBut except from that I'm not a big fan. It fellt too much like it wanted to be bigger, a spectacle to finish the series. But I rather have a slow and scary scenes instead of a tornado excorcism and teleporting witches.\nThey also could've done a lot more with the court case. It should've been the central Point of the story\nI like the series , only wished it ended stronger.", "596" ], [ "Crimes of the Future\nIm so glad i've watched it! It feels like <PERSON> is getting back to where he's started. As I could've seen this is a provocative work, which its background happens in the future (?) where performance artists are like rockstars, and \"surgery is the new sex\". People are growing internal organs and they get tattoos and be displayed for the public, as an work of art.", "282" ], [ "This is science meeting art. As the movie flows, we are invited to a moral debate. Has art the potencial to create the cure for humanity? And IF it does, how would humankind deal with it? The hypersensibily of the artistical classes is contrapointing to the mothers obsession about her son's \"monstruosity\".\nVery very good movie, highly recomended.\nPs.: it reminds me a little of <PERSON> Cyborg Manifest.", "80" ], [ "Blue Beetle\nThis movie was 10 years too late to be cool.\nThe plot is identical to Ant-Man. A suit is stolen, the main character puts it on and is basically forced to become a superhero. There’s also a villain who is the same as the hero but a different color. Red Beetle! lets gooo!!!\nThe suit is like a mix between iron spider and moon knight.", "387" ], [ "The suit talks to the guy like in homecoming and it covers his body on command like moon knight.\nThe family dynamic is like Ms <PERSON>. Both families are part of a minority group in America and they support the hero by being kind of annoying.\nPossibly the middest movie I’ve ever seen. There was nothing good and also nothing bad. Best DC movie of the year so far!!", "217" ], [ "Fanatic\nI lost count how many times I checked the time\nI think Fanatic is a slow uninspiring drag which is bland and unrewarding throughout majority of it.\nThe ideolic concept of this old woman being a fanatic to religious values is left flat and unexplored beyond the surface level of restricting the virtues of a prisoner.\nAn idea like Fanatic's feels too small for 97 minute run time that felt like a frustrating 3 fucking hours, as a result we get a basic filler narative piled on top of boring sequences of <PERSON> failing to escape the midst of <PERSON> who never shuts up raving on about her dead son no one gives a shit about in the first place.\nThe mystery of <PERSON> is the most interesting part and was anticipating in the finale with his painting and the his alluring spirit but is left waiting in a writing purgatory, no enticing progression in story, repetitive events that posses minimal thrill and lead to nothing.\nSome great acting was no compromise on an idea which wastes it's own time.", "952" ], [ "Boss <PERSON>\nHow much does any one person want to see <PERSON> die over and over again in a time loop movie? Well on the surface I'm completely game for that but director <PERSON> lumbers the picture with an ever present voice-over narration which labours the movie somewhat. I was beginning to question if actual dialogue between characters in the scene would actually happen.", "647" ], [ "Not that it needed to, this one didn't need to be a talky, the dialogue is a bit naff and it doesn't help that <PERSON> and <PERSON> are in complete paycheck mode either. <PERSON> isn't a bad presence though, there is something likeable about him, like the TV Movie action hero getting a chance to level up. This is completely B-Grade quality though, not without its pleasures for sure but not one that will live long in the memory either.", "698" ] ]

[ 7973, 4498, 6861, 3319, 11134, 2901, 5013, 845, 9271, 4954, 1623, 5457, 3364, 4696, 305, 4426, 1990, 11034, 8905, 10530, 7194, 8693, 4367, 1566, 6657, 2152, 6832, 3279, 11012, 5743, 135, 727, 9863, 8258, 1057, 8788, 5646, 2145, 6797, 6371, 4931, 9673, 9344, 3570, 9699, 59, 9937, 6226, 11006, 3658, 6450, 10165, 3020, 5581, 8659, 3802, 10008, 2507, 11016, 676, 2956, 1794, 1636, 9361, 2952, 2625, 4118, 5324, 8482, 8763 ]