praj-17/QA-MCQ-Open-ended huggingface dataset:
Title: Bacteria
Context: Bacterial infections may be treated with antibiotics, which are classified as bacteriocidal if they kill bacteria, or bacteriostatic if they just prevent bacterial growth. There are many types of antibiotics and each class inhibits a process that is different in the pathogen from that found in the host. An example of how antibiotics produce selective toxicity are chloramphenicol and puromycin, which inhibit the bacterial ribosome, but not the structurally different eukaryotic ribosome. Antibiotics are used both in treating human disease and in intensive farming to promote animal growth, where they may be contributing to the rapid development of antibiotic resistance in bacterial populations. Infections can be prevented by antiseptic measures such as sterilizing the skin prior to piercing it with the needle of a syringe, and by proper care of indwelling catheters. Surgical and dental instruments are also sterilized to prevent contamination by bacteria. Disinfectants such as bleach are used to kill bacteria or other pathogens on surfaces to prevent contamination and further reduce the risk of infection.

question: What type of antibiotics called bacterocidal? 

answer: if they kill bacteria

question: What kind of antibiotics are used for prevention of bacterial growth 

answer: bacteriostatic

question: What is the drawback of using antibiotics if agriculture? 

answer: rapid development of antibiotic resistance in bacterial populations

question: Besides in treating human disease where else are antibiotics used? 

answer: in intensive farming to promote animal growth

question: What is common prevention method of infections in medicine? 

answer: sterilizing
Title: Bacteria
Context: The ability of bacteria to degrade a variety of organic compounds is remarkable and has been used in waste processing and bioremediation. Bacteria capable of digesting the hydrocarbons in petroleum are often used to clean up oil spills. Fertilizer was added to some of the beaches in Prince William Sound in an attempt to promote the growth of these naturally occurring bacteria after the 1989 Exxon Valdez oil spill. These efforts were effective on beaches that were not too thickly covered in oil. Bacteria are also used for the bioremediation of industrial toxic wastes. In the chemical industry, bacteria are most important in the production of enantiomerically pure chemicals for use as pharmaceuticals or agrichemicals.

question: What quality of bacteria is being widely used re-cyling? 

answer: ability of bacteria to degrade a variety of organic compounds

question: What is being used in cleaning up oil spills? 

answer: Bacteria

question: What other way is bacteria aiding to nature? 

answer: used for the bioremediation
Title: Bacteria
Context: Because of their ability to quickly grow and the relative ease with which they can be manipulated, bacteria are the workhorses for the fields of molecular biology, genetics and biochemistry. By making mutations in bacterial DNA and examining the resulting phenotypes, scientists can determine the function of genes, enzymes and metabolic pathways in bacteria, then apply this knowledge to more complex organisms. This aim of understanding the biochemistry of a cell reaches its most complex expression in the synthesis of huge amounts of enzyme kinetic and gene expression data into mathematical models of entire organisms. This is achievable in some well-studied bacteria, with models of Escherichia coli metabolism now being produced and tested. This understanding of bacterial metabolism and genetics allows the use of biotechnology to bioengineer bacteria for the production of therapeutic proteins, such as insulin, growth factors, or antibodies.

question: What sciences use bacteria? 

answer: molecular biology, genetics and biochemistry
Title: Bacteria
Context: Bacteria were first observed by the Dutch microscopist Antonie van Leeuwenhoek in 1676, using a single-lens microscope of his own design. He then published his observations in a series of letters to the Royal Society of London. Bacteria were Leeuwenhoek's most remarkable microscopic discovery. They were just at the limit of what his simple lenses could make out and, in one of the most striking hiatuses in the history of science, no one else would see them again for over a century. Only then were his by-then-largely-forgotten observations of bacteria — as opposed to his famous "animalcules" (spermatozoa) — taken seriously.

question: When was the first time bacteria were observed? 

answer: 1676

question: Who discovered bacteria? 

answer: Dutch microscopist Antonie van Leeuwenhoek

question: How was he able to see bacteria? 

answer: using a single-lens microscope of his own design

question: How long did it take for his discovery to be taken seriously? 

answer: over a century
Title: Bacteria
Context: Though it was known in the nineteenth century that bacteria are the cause of many diseases, no effective antibacterial treatments were available. In 1910, Paul Ehrlich developed the first antibiotic, by changing dyes that selectively stained Treponema pallidum — the spirochaete that causes syphilis — into compounds that selectively killed the pathogen. Ehrlich had been awarded a 1908 Nobel Prize for his work on immunology, and pioneered the use of stains to detect and identify bacteria, with his work being the basis of the Gram stain and the Ziehl–Neelsen stain.

question: When was the first antibiotic discovered? 

answer: In 1910

question: Who was the creator of antibiotic? 

answer: Paul Ehrlich

question: What bacteria did he treat first? 

answer: Treponema pallidum

question: Who based their research on Enrlich's stains works? 

answer: Gram stain and the Ziehl–Neelsen

question: How was his discovery aknowledged? 

answer: had been awarded a 1908 Nobel Prize
Title: Printed_circuit_board
Context: When the board has no embedded components it is more correctly called a printed wiring board (PWB) or etched wiring board. However, the term printed wiring board has fallen into disuse. A PCB populated with electronic components is called a printed circuit assembly (PCA), printed circuit board assembly or PCB assembly (PCBA). The IPC preferred term for assembled boards is circuit card assembly (CCA), and for assembled backplanes it is backplane assemblies. The term PCB is used informally both for bare and assembled boards.

question: What's the abbreviation for a printed wiring board? 

answer: PWB

question: What organization likes the term "circuit card assembly" for boards that have already been assembled? 

answer: IPC

question: What would we call a printed circuit board with embedded electronics, abbreviated PCA? 

answer: printed circuit assembly

question: What's the more appropriate, but mostly unused, name for a printed circuit board when it doesn't have embedded components? 

answer: printed wiring board

question: What abbreviation would the IPC use for an assembled circuit board? 

answer: CCA
Title: Printed_circuit_board
Context: Initially PCBs were designed manually by creating a photomask on a clear mylar sheet, usually at two or four times the true size. Starting from the schematic diagram the component pin pads were laid out on the mylar and then traces were routed to connect the pads. Rub-on dry transfers of common component footprints increased efficiency. Traces were made with self-adhesive tape. Pre-printed non-reproducing grids on the mylar assisted in layout. To fabricate the board, the finished photomask was photolithographically reproduced onto a photoresist coating on the blank copper-clad boards.

question: In the old PCB design method, what was used to connect component pin pads? 

answer: traces

question: What did PCB designers used to employ on a mylar sheet? 

answer: photomask

question: What were traces originally made out of? 

answer: self-adhesive tape

question: Designers would rub on a dry transfer of what to make the process of laying out components simpler? 

answer: common component footprints

question: What kind of metal coated the blank boards used to make PCBs? 

answer: copper
Title: Printed_circuit_board
Context: Panelization is a procedure whereby a number of PCBs are grouped for manufacturing onto a larger board - the panel. Usually a panel consists of a single design but sometimes multiple designs are mixed on a single panel. There are two types of panels: assembly panels - often called arrays - and bare board manufacturing panels. The assemblers often mount components on panels rather than single PCBs because this is efficient. The bare board manufactures always uses panels, not only for efficiency, but because of the requirements the plating process. Thus a manufacturing panel can consist of a grouping of individual PCBs or of arrays, depending on what must be delivered.

question: What process groups PCBs before transfer to a panel? 

answer: Panelization

question: Is it more common for panels to have a single design or many designs? 

answer: a single design

question: What type of panels can also be referred to as an "array?' 

answer: assembly panels

question: What step of the bare board manufacture would be impossible if panels weren't always used? 

answer: the plating process

question: Besides assembly panels, what's the other type of panel? 

answer: bare board manufacturing panels
Title: Printed_circuit_board
Context: The panel is eventually broken apart into individual PCBs; this is called depaneling. Separating the individual PCBs is frequently aided by drilling or routing perforations along the boundaries of the individual circuits, much like a sheet of postage stamps. Another method, which takes less space, is to cut V-shaped grooves across the full dimension of the panel. The individual PCBs can then be broken apart along this line of weakness. Today depaneling is often done by lasers which cut the board with no contact. Laser panelization reduces stress on the fragile circuits.

question: What is the process called whereby the individual PCBs are separated? 

answer: depaneling

question: What boundaries would you follow to separate PCBs on a panel? 

answer: individual circuits

question: What technology has made depaneling possible without needing to physically interact with the board? 

answer: lasers

question: What does the V-shaped groove method save? 

answer: space

question: What delicate component is less likely to be damaged if laser depanelization is used? 

answer: circuits
Title: Printed_circuit_board
Context: Subtractive methods remove copper from an entirely copper-coated board to leave only the desired copper pattern. In additive methods the pattern is electroplated onto a bare substrate using a complex process. The advantage of the additive method is that less material is needed and less waste is produced. In the full additive process the bare laminate is covered with a photosensitive film which is imaged (exposed to light through a mask and then developed which removes the unexposed film). The exposed areas are sensitized in a chemical bath, usually containing palladium and similar to that used for through hole plating which makes the exposed area capable of bonding metal ions. The laminate is then plated with copper in the sensitized areas. When the mask is stripped, the PCB is finished.

question: Do additive or subtractive methods use less raw materials? 

answer: additive

question: What object is used to expose selected parts of the photosensitive film to light? 

answer: mask

question: What chemical element is often present in the bath used to sensitive exposed film after it's been imaged? 

answer: palladium

question: In subtractive methods, what metal covers the board and is then partially removed? 

answer: copper

question: In the additive method, which parts of the laminate are plated with copper? 

answer: sensitized areas
Title: Printed_circuit_board
Context: Semi-additive is the most common process: The unpatterned board has a thin layer of copper already on it. A reverse mask is then applied. (Unlike a subtractive process mask, this mask exposes those parts of the substrate that will eventually become the traces.) Additional copper is then plated onto the board in the unmasked areas; copper may be plated to any desired weight. Tin-lead or other surface platings are then applied. The mask is stripped away and a brief etching step removes the now-exposed bare original copper laminate from the board, isolating the individual traces. Some single-sided boards which have plated-through holes are made in this way. General Electric made consumer radio sets in the late 1960s using additive boards.

question: In the semi-additive process, what do the areas exposed by the mask become at the end? 

answer: traces

question: What metal is used to plate the unmasked parts of the board in the semi-additive method? 

answer: copper

question: After the mask comes off of the board, what step takes off the original plating? 

answer: etching

question: What company used to make radios with additive boards in the mid-20th century? 

answer: General Electric

question: What weight of plating is possible with copper? 

answer: any
Title: Printed_circuit_board
Context: The simplest method, used for small-scale production and often by hobbyists, is immersion etching, in which the board is submerged in etching solution such as ferric chloride. Compared with methods used for mass production, the etching time is long. Heat and agitation can be applied to the bath to speed the etching rate. In bubble etching, air is passed through the etchant bath to agitate the solution and speed up etching. Splash etching uses a motor-driven paddle to splash boards with etchant; the process has become commercially obsolete since it is not as fast as spray etching. In spray etching, the etchant solution is distributed over the boards by nozzles, and recirculated by pumps. Adjustment of the nozzle pattern, flow rate, temperature, and etchant composition gives predictable control of etching rates and high production rates.

question: What non-professionals might use immersion etching, since it's the easiest way to make a PCB? 

answer: hobbyists

question: If you wanted to speed up the etching process, you could agitate the bath up or add what to it? 

answer: Heat

question: Is the immersion etching process long or short compared to other production methods? 

answer: long

question: What funny name is used for the etching process where air is blown through the etching solution to get it moving around? 

answer: bubble etching

question: What's the fastest and most easily controlled process for etching? 

answer: spray etching
Title: Printed_circuit_board
Context: Multi-layer printed circuit boards have trace layers inside the board. This is achieved by laminating a stack of materials in a press by applying pressure and heat for a period of time. This results in an inseparable one piece product. For example, a four-layer PCB can be fabricated by starting from a two-sided copper-clad laminate, etch the circuitry on both sides, then laminate to the top and bottom pre-preg and copper foil. It is then drilled, plated, and etched again to get traces on top and bottom layers.

question: If you started with a two-sided laminate etched on either side, laminated to the top and bottom, and processed it again to get traces on the outside layers, how many layers would your final PCB have? 

answer: four

question: What makes up the inside of a multi-layer PCB? 

answer: trace layers

question: Pressure is one thing you need to apply to make a multi-layer PCB; what's the other thing? 

answer: heat

question: What tool is used to push the trace layers in a multi-layer PCB together? 

answer: press
Title: Printed_circuit_board
Context: Holes through a PCB are typically drilled with small-diameter drill bits made of solid coated tungsten carbide. Coated tungsten carbide is recommended since many board materials are very abrasive and drilling must be high RPM and high feed to be cost effective. Drill bits must also remain sharp so as not to mar or tear the traces. Drilling with high-speed-steel is simply not feasible since the drill bits will dull quickly and thus tear the copper and ruin the boards. The drilling is performed by automated drilling machines with placement controlled by a drill tape or drill file. These computer-generated files are also called numerically controlled drill (NCD) files or "Excellon files". The drill file describes the location and size of each drilled hole.

question: What kind of material sometimes used for drilling will lose sharpness quickly if used for PCBs? 

answer: high-speed-steel

question: What property do PCBs have that makes them tough to drill through? 

answer: abrasive

question: What kind of drill bit do you need to drill holes in a PCB? 

answer: coated tungsten carbide

question: What's another name for NCD files that has an "x" in it? 

answer: Excellon files

question: What does the "NCD" in "NCD files" mean? 

answer: numerically controlled drill
Title: Printed_circuit_board
Context: The hole walls for boards with two or more layers can be made conductive and then electroplated with copper to form plated-through holes.  These holes electrically connect the conducting layers of the PCB. For multi-layer boards, those with three layers or more, drilling typically produces a smear of the high temperature decomposition products of bonding agent in the laminate system. Before the holes can be plated through, this smear must be removed by a chemical de-smear process, or by plasma-etch. The de-smear process ensures that a good connection is made to the copper layers when the hole is plated through. On high reliability boards a process called etch-back is performed chemically with a potassium permanganate based etchant or plasma. The etch-back removes resin and the glass fibers so that the copper layers extend into the hole and as the hole is plated become integral with the deposited copper.

question: What do the hole walls in two-layer PCBs have to be before they can be electroplated? 

answer: conductive

question: What's the minimum number of layers a PCB can have to be considered "multi-layer"? 

answer: three

question: What process does a multi-layer PCB usually undergo before plating to make sure the layers have good connectivity with each other? 

answer: de-smear

question: What type of boards undergo the etch-back process? 

answer: high reliability

question: Etch-back removes glass fibers and what other material? 

answer: resin
Title: Printed_circuit_board
Context: Matte solder is usually fused to provide a better bonding surface or stripped to bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickly, and therefore is not readily solderable. Traditionally, any exposed copper was coated with solder by hot air solder levelling (HASL). The HASL finish prevents oxidation from the underlying copper, thereby guaranteeing a solderable surface. This solder was a tin-lead alloy, however new solder compounds are now used to achieve compliance with the RoHS directive in the EU and US, which restricts the use of lead. One of these lead-free compounds is SN100CL, made up of 99.3% tin, 0.7% copper, 0.05% nickel, and a nominal of 60ppm germanium.

question: What happens to untreated copper that makes it difficult to solder? 

answer: oxidizes

question: What chemical treatment will prevent bare copper from oxidizing? 

answer: benzimidazolethiol

question: What's the process by which bare copper gets covered in solder? 

answer: hot air solder levelling

question: What does hot air solder leveling ensure the coated copper will have? 

answer: solderable surface

question: What alloy can no longer be used in HASL because of restrictions on the use of one of its metal components? 

answer: tin-lead
Title: Printed_circuit_board
Context: Other platings used are OSP (organic surface protectant), immersion silver (IAg), immersion tin, electroless nickel with immersion gold coating (ENIG), electroless nickel electroless palladium immersion gold (ENEPIG) and direct gold plating (over nickel). Edge connectors, placed along one edge of some boards, are often nickel plated then gold plated. Another coating consideration is rapid diffusion of coating metal into Tin solder. Tin forms intermetallics such as Cu5Sn6 and Ag3Cu that dissolve into the Tin liquidus or solidus(@50C), stripping surface coating or leaving voids.

question: What does OSP stand for? 

answer: organic surface protectant

question: What metal is often under the gold plating on edge connectors? 

answer: nickel

question: What's the abbreviation for immersion silver plating? 

answer: IAg

question: Ag3Cu is one intermetallic that tin forms; what's the other one? 

answer: Cu5Sn6

question: What might the rapid diffusion of coating metal into tin solder leave in the surface coating? 

answer: voids
Title: Printed_circuit_board
Context: Electrochemical migration (ECM) is the growth of conductive metal filaments on or in a printed circuit board (PCB) under the influence of a DC voltage bias. Silver, zinc, and aluminum are known to grow whiskers under the influence of an electric field. Silver also grows conducting surface paths in the presence of halide and other ions, making it a poor choice for electronics use. Tin will grow "whiskers" due to tension in the plated surface. Tin-Lead or solder plating also grows whiskers, only reduced by the percentage Tin replaced. Reflow to melt solder or tin plate to relieve surface stress lowers whisker incidence. Another coating issue is tin pest, the transformation of tin to a powdery allotrope at low temperature.

question: What's the process whereby metal filaments are grown on or in a PCB via DC voltage? 

answer: Electrochemical migration

question: Along with silver and aluminum, what metal grows metal filaments when exposed to an electric field? 

answer: zinc

question: In addition to "whiskers," what does silver sprout around ions like halide? 

answer: conducting surface paths

question: What do scientist call the function whereby tin changes when it's very cold? 

answer: tin pest

question: What's present in plated surfaces that causes tin to grow metal filaments? 

answer: tension
Title: Printed_circuit_board
Context: Areas that should not be soldered may be covered with solder resist (solder mask). One of the most common solder resists used today is called "LPI" (liquid photoimageable solder mask).  A photo-sensitive coating is applied to the surface of the PWB, then exposed to light through the solder mask image film, and finally developed where the unexposed areas are washed away. Dry film solder mask is similar to the dry film used to image the PWB for plating or etching. After being laminated to the PWB surface it is imaged and develop as LPI. Once common but no longer commonly used because of its low accuracy and resolution is to screen print epoxy ink. Solder resist also provides protection from the environment.

question: If part of a PCB isn't solderable, what can be used instead? 

answer: solder resist

question: What's another term used for "solder resist"? 

answer: solder mask

question: What solder resist with a four-word name is a popular choice in the industry? 

answer: liquid photoimageable solder mask

question: What kind of coating gets applied to the PWB before light exposure? 

answer: photo-sensitive

question: What solder resist is so inaccurate that few choose it anymore? 

answer: screen print epoxy ink