darklight03/StackMIAsub huggingface dataset:
In practical engineering we are limited in the upper temperature of thermodynamic cycle due to the material properties. So, after the max temperature is fixed, we want to make our cycle as close as possible to a Carnot cycle with the same max temperature. It is clear that the compression and expansion should be adiabatic and we are technically close to the realization of this. Also, we have to cut lower right angle of the Carnot cycle, because each next turbine stage should be larger in diameter, and building them becomes economically or technically impractical at a certain point. But the process of heat addition is a bit more tricky to understand. Consider the case of Humphrey and Brayton cycles in the same range of temperatures: The heat addition process is more vertical in case of faster heat addition, but according to Carnot process it should be more horizontal to be more efficient (i.e. close to isothermal). However, we do know that faster heat addition is more efficient (detonation engines are more efficient), so Humphrey cycle should be more efficient. Can't solve this puzzle...
I have viewed the definitions of the Hubble Sphere and related cosmological concepts, as well as various explanations, yet Im still struggling to comprehend a full visualisation of this, which I would prefer instead of taking its word for it. To phrase the question that would most help me, the following follows: so from the moment that a celestial object crosses the hubble sphere boundary, as in going out of our hubble sphere scope, the images of that object will never reach us, the observer, from that point on, and we are left with a developing and cascading history of prior images only just reaching us now. If what I said is accurate, and requires no correction, my question now is how will the developing and changing history of past images for this celestial object play out in our view for the next millions of years until that moment in the old present where it crossed the Hubble Sphere boundary? How would it appear to us, the observer, over such a long term period? My intuition is telling me that such a celestial object will continue to age in our view of its past images, but also becoming increasingly redshifted until phoof, it is no longer visible due to being outside of the Hubble sphere.
I understand that infalling objects reach the speed of light at the event horizon. Any associated clock would be observed to stop, according to SR. But isn't the key here 'observed'? An infalling observer at the event horizon would observe a remote clock to stop. Who is to say which clock stops. No clocks actually stop in SR, because it is symmetrical. But there is gravitational time dilation. In this case clocks really slow down. But you would expect the force of gravity to be infinite at the singularity. It is here you would expect gravitational time dilation to be infinite and clocks would really stop, not just be observed to stop. The force of gravity is nowhere near infinite at the event horizon, so why would clocks stop here rather than just slow down? Do properties at the singularity transfer themselves to the event horizon? Perhaps because there is no physical singularity?
This paper has the following abstract: We theoretically consider a graphene ripple as a Brownian particle coupled to an energy storage circuit. When circuit and particle are at the same temperature, the second law forbids harvesting energy from the thermal motion of the Brownian particle, even if the circuit contains a rectifying diode. However, when the circuit contains a junction followed by two diodes wired in opposition, the approach to equilibrium may become ultraslow. Detailed balance is temporarily broken as current flows between the two diodes and charges storage capacitors. The energy harvested by each capacitor comes from the thermal bath of the diodes while the system obeys the first and second laws of thermodynamics. Can someone explain the importance/meaning of the claimed result for a layperson? In particular, how does this not violate the second law, if it's "thermodynamic fluctuations" being harvested?
I am working on this problem. A hexagon is inscribed in a circle. The length of five of its sides is a, while the length of the six side is b. My question is : a. How to find the area of this hexagon? b. how to find the each of the diagonals's length? What I have in mind is that, since only one side is different from all other sides, the figure is still symmetric. Then I can calculate the area of the two trapezoids. I think I should use the condition that it is inscribed in a circle. However, I am stuck with how to find the angles or what other fomula should be used here. Then for the length of the diagonals, I am thinking that once I got the two trapezoids, I got them. Anyway, I think I lack of the knowledge of some intermediate theorems. Thank you for the help in advance!
This question closely ties into a question I had about verbless clauses. However, I am writing a new one at the suggestion of a user. Polarity-sensitive aspectual-related words are those such as 'still' and 'already.' I have established that modifiers like 'obviously,' which I believe to be evaluative in nature, can function as modifiers in an adjective phrase, as determined by the answer to my question linked above, where I confused them to be part of verbless clauses. But can 'still' and 'already' also be modifiers in an adjective phrase? Below is an example similar to the one from my previous question, using 'still' instead of 'obviously.' I have highlighted in bold what I believe to be the complete adjective phrase. He was crying, still sad because of the passing of his father.
According to my current understanding of special relativity, photons do not experience the passage of time. It is as though the universe is completely 'paused' for them. I know that objects with mass cannot accelerate to the speed of light. But isn't the whole point of relativity to predict the motion of an object from a different frame of reference? The universe also tends to increase its size with time. In that case, consider the following thought experiment: Let's go back in time to when the universe was relatively young. There was once a photon which, when created, observed the universe to be completely stationary as it didn't experience the ticking of time. As the time does not tick, the universe doesn't expand (relative to the photon) and instantaneously, it exits the universe. So my question is, what part(s) of the above statements is false?
I made the claim on a manuscript that all manifolds possess an acceleration field. The referee rejected the idea saying "The nature of this acceleration field has not been seriously discussed and the theory lacks justification in physics". This confused me as I understand that a field, in physics, is a region of space for which each point is associated with a specific physical quantity. Velocity is a physical quantity. If we impose an evolution parameter, then don't all points on this manifold have a velocity (vector) quantity? Is that not sufficient to claim the manifold has a velocity field? Can we not also take the second derivative of the position with respect to our evolution parameter and say that every point on a manifold has an acceleration (vector) quantity? Does that not also qualify as a field? Is there an argument to be made that all smooth, differentiable manifolds do not possess an acceleration field?
I am looking for a word that describes something whose meaning is instantly recognizable, that is so simple as to be offensively lazy, and yet completely apropos. Such a word might describe Kazimir Malevich's painting Black Square: Chef's kiss conveys artfulness and minimalism, but not to the point of laziness or offense. I like sophomoric for its literal translation "wise fool", but the word is not used to suggest brilliance. Cunning has the right connotation of artfulness, but its connotations of subtlety, and further, deception, make it inappropriate. Stupidly/offensively obvious almost works, but is boring. Unsubtle is ok; blunt better. Both don't convey the artfulness that I'm looking for. I love the divine feel of manifest; I'm wondering if this is the best I can do. I'm tempted to coin kazimirean, but of course that's too indulgent.
Let's bring a positively charged rod near a conductor. Now since some electrons in outer shells are not strongly bound to atoms,they will get to the side near the rod. But why does it mean that dipole is formed in that conductor? We take the vertical cross sections of the conductor. Now,in each vertical layer,there will be atoms. So electrons from each vertical layer will get to the side of the rod. If that happens,except from the region closest to the rod,there will be positive charge in every cross section. Hence,apart from the very region towards the rod,the entirety of the conductor will be positively charged since electrons have left from each of the cross sections. As we can see dipole(positive at one side and negative on another side) hasn't been created,rather negative at a very small region and positive charges throughout the rest of the conductor. The logic that the rod will push the positive charges at the extreme end also doesn't work since atoms are firmly immovable. So why is it still said that dipole is created as a result of electrostatic induction whereas we have proved that it isn't the case?
In basic physics lectures, the teacher or professor in my class never explains the behavior of rotating two or many body particles. In my experience and intuition doing physics, two-particle or many-body systems tend to rotate about their center of mass. For example, the earth-sun rotates around its center of mass, or two black holes rotate around its center of mass; also in ideal conditions, without air friction, a stick when a force is applied to it at the end edge, stick will rotate around its center of mass. Can anyone explain the physics of a system of mass that tends to rotate around its center of mass? I tried to solve this problem and read some reference books, but I don't have any conclusion. most of the books I read just explain what rotation or torque is. Or, is my intuition wrong?
I'm hoping maybe this is the right spot for this question, if not, I would love for someone to suggest a better spot I am attempting to use SOLIDWORKS flow simulation to simulate the airflow through a ram air duct. Think like a venturi tube on an airplane, but the convergent divergent duct is embedded in the structure rather than being a protrusion. The issue I'm having, is that for the area ratio of the entrance to the throat, I don't get the velocities I expect at the throat when doing an external flow sim. When I build just the duct itself and put lids on it and do an internal sim I get the numbers I expect. Is there any deficiency in the Flow Simulation when using the external simulation and the flow must through a completely bounded flow area? Or is the simulation giving me true results and the flow through the duct is that degraded by being embedded in the larger structure moving through the air?
Intuitionistic logic can't prove as many sentences as classical logic, for example: Peirce's Law; Reductio Ad Absurdum; Double Negation Elimination; and Tertium Non Datur, which are all equivalent in classical propositional calculus and they can't be proved in intuitionistic systems. I can prove their equivalences in some famous system, but I can't prove that we can't prove all of them in intuitionistic proof system especially without using semantics. I would like to prove this fact only using syntactic properties, i.e. proving these formulas are not in the set of provable sentences or proving that there aren't any proof of them in the set of proofs of intuitionistc proof system, without interpretation into some semantics: Kripke models or Heyting algebra. Where can I read this topic? is there any great book for this proof?
I'm using pandoc in my website to allow my content creators to use Word, which would simplify developmnent immensely. The only issue I have is that Pandoc seems to output very little information about document styling. It's possible for me to manually re-add these with CSS later, but that somewhat defeats the pupose of using Word. Hence my question. Can I get pandoc to spit out more information about how my document is structured, such that I can apply more generic styles and have the document looking comparable to how it was written. Example, I've got a table with user-defined centre-aligned text (the person centred the text in Word). When I export my document to HTML using the following command: pandoc --from docx --to html --embed-resources --reference-doc ./reference.docx --section-divs. (I'm streaming in the contents of the file via stdin, as it isn't guaranteed to be in a consistent location)`. When the HTML comes back, the contents of the table elements are simply paragraphs. I'd like them to be wrapped in <center> tags or the equivalent - just something to identify that they need to be centred. There's a number of examples like these that I'd like to introduce, but momentarily, centring text is a priority. Thanks for any pointers
When there is wind at a surface, and a rotating cylinder is placed there, mounted in a way that it is free to reorient itself, can it be predicted if the cylinder will align itself in a certain way? Perhaps it is easier to first consider the same scenario but without a surface. So, simply, a rotating cylinder in wind. Can it be predicted if it will prefer to orient itself in a certain way? A cylinder with its axis perpendicular to the wind direction, will for example experience lift. Is there anything to suggest a rotating cylinder, free to orient itself in any direction, will prefer to orient itself perpendicular to the wind (its axis perpendicular), such that it also develops lift? And, what if a surface is then added? May be possible to make an analogy to how cylinders rotating in the same direction repel while those rotating in opposite direction attract. In this case, the surface with wind over it may "appear" similar to the surface of a rotating cylinder.
It is very common in physics, when we refer to the most diverse theories, on the most diverse length scales, we also refer to their energy scale. It is through the energy scale that we classify a theory as being classical, quantum, or relativistic, for example. Likewise, on such a scale, we know whether we are dealing with sub-atomic or sub-nuclear particles. Thus, when constructing a theory, it seems to be of vital importance for the physicist to understand where such a theory lies on the underlying energy scale. However, for a young physicist student, it is not always easy to make such a correlation and find available material that deals with the subject in a didactic way. So, the question of how to determine the energy scale of a physical theory and classify it in the energy scale of physical phenomena remains somewhat nebulous, without many students realizing the importance of knowing how to classify the energy regime of a given theory. From this, as the question in the title of this topic already delivers, I would like to know how, given any physical theory, one can determine its energy and classify it according to the cosmic energy scale (I don't know if I can call it so: "cosmic energy" scale.). I would like, if possible, indications of references that deal with the subject.
I was walking by the sidewalk during the night when I noticed a swarm of flies circling a street lamp. It was difficult to see at first, so I tried looking in different angles. The security gate came in by pure chance between me and the streetlight. Now the insects became crystal clear. I tried to capture this in camera, and the same effect can be observed. Now the object between me and the streetlight doesn't matter. My umbrella, or even my hand also works. I would like to know why exactly the blocking of the dominant light source allows the less dominant ones to be seen. The light from the less dominant ones were still present before blocking the light. What roles does blocking play here? Many a times me and my friends have to abandon astrophotography camps in the night due to an overly bright moon or street lamp nearby. Can this same method be utilized to capture a clear image of stars in the night sky?
My teacher gave us the assignment to find the moment of inertia of any shape you want. So I decided to find the moment of inertia of our milky way galaxy. I found out that our galaxy is shaped like a warped disk, not a flat. After I found out that, I looked for the equation of the shape and density distribution of the Milky Way to find its I. But, to me, Nasa's and some high university papers had so many big wards that I could bearly understand what they were talking about(I'm Korean.. ^^). I'm sure that I can understand the equation if I had it, but I just can't find any information about them. I would really appreciate it if someone could tell me what you know about this equation(shape & density distribution) Thank you! (Img)Dorota M. Skowron, A three-dimensional map of the Milky Way using classical Cepheid variable stars
I was watching this video on Hall effect, and to demonstrate that it is not electric fields that are bending the electron beam, the presenter puts a metal plate between the magnet and the beam. So, my question is, say there was a charge instead of the magnet. How will the metal plate shield the electric field produced by a charge? My reasoning till now was, say, you put a positive charge in front of the metal. Since the electric field inside the metal is zero, negative charges will develop on the face near the charge, and to maintain charge conservation, a positive charge will develop on the other face of the metal. So, in effect, the plate has done nothing. There are still positive charges pointing toward the beam, and the beam will still perceive a force from the charge. So, how is the metal plate acting as a shield? ( If I assume that the plate is grounded, then I can say that the plate will serve as a shield. But in the video, it is not grounded.)
Some visuals are so obvious that you would think proofs are not needed. But then trying to proof them rigouresly is a whole other kettle of fish. I was stumped by the following puzzle I made for myself: (really it is no homework question) How do you proof that the axis of an ellipse are perpendicular? Yes you can see it, it is obvious but seeing in itself is no proof. Yes you cannot construct a countermodel, but again that is no proof. I am really stumped with this one, it is so obvious, and easy to see, but a proof? As definition of an ellipse I want to use: (reused from Wikipedia) An ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the points is a constant. As definition of the axis i want to use: (all made up by myself, so maybe incorrect, the second one, defining the minor axis, was a real struggle ;) The first axis of the ellipse is the line containing the longest segment possible between two points on the ellipse. The second axis of the ellipse is the line containing the midpoint of the two focal points and the shortest segment possible between two points on the ellipse,
Good afternoon everyone, I am currently resetting my mac and reinstalling everything in a clean way. I would love to have guidance here if possible. I currently installed TexLive and TextDist but now i am guiding myself with this : https://github.com/James-Yu/LaTeX-Workshop/wiki/Install If anyone could explain to me this section : Setting PATH environment variable After installing TeX Live, you must add the directory of TeX Live binaries to your PATH environment variable except on Windows. See the official document. LaTeX Workshop never touches the variable. If VS Code cannot find executables of TeX, it means that the setting of your system is broken. For the ways of setting environment variables on Windows, see link or link. On macOS and Linux, see the documentation by the rbenv dev team. Very detailed information is also available on stackoverflow for macOS. Notice that you have to restart VS Code and the operating system after changing the variable. If you can not fix the setting of your system, you can also override PATH with the env property of LaTeX tools in LaTeX recipes. Notice that, to set the PATH environment variable for VS Code Remote Development, you usually have to edit .bash_profile or .profile instead of .bashrc. See the document for WSL and an issue for Remote SSH. If you want to know about environment variable itself, please read Wikipedia and stackexchange. I do not really understand how it is important and what to do if anyone could help here !
I often have to translate sentences such as: The Department of Environment has offices everywhere in the country, and we would love for you to join us [us as in "the whole department, and not a specific team]. Or: The Police Department is assigning as many resources possible to the case, but we [the Police Department] cannot counter these threats alone I've been told quite a few times that a switch from the third person singular to the first person plural like that is to be avoided in French (supposedly because "we" could refer to anything and cause confusion, even in simple cases like these), and was wondering if the same kind of rule applies in English. I couldn't find any grammar or style guide to help me with this. All help is appreciated, thanks.
I have a great interest in synthetic geometry since I was in senior high school. Although I have graduated from university I still like them now. When I was in high school, I read many textbooks and exercise books about synthetic geometry of mathematical competition and learned many interesting things like harmonic range and inversion transformation. But I think people must have invented something new. I am really curious about what new techniques synthetic geometry has developed other than I learned in old textbooks and I want to know if there are any reference on modern synthetic geometry. Also I want to learn how synthetic geometry studies other curves such as conic curves, especially ellipses. I have read the book Geometry of Conics, and the Conics Books by Apollonius, but I hope I could read more such books with deeper results, like those ordinary mathematical competition books with various theorems and interesting and difficult exercices. On a Chinese forum I find out that there are many people discussing modern synthetic geometry and writing short essays on various topics, but I hope I can read some systematic reference books. Thank you in advance.
I have a problem I fail to research properly, so I hope you may at least push me in the right direction (or maybe even provide me an answer right away?). I know how linear regression works, that it attempts to find a linear curve such that the sum of all residual errors to the square of the given data points is minimal (least squares). Now, how does one go about, when data points have deviations attached? I have a set of data points, where every point has a unique deviation. The linear regression should still work as usual, but how do I get the resulting error bar of the linear regression curve? Also, since deviations fluctuate, I'd assume some sort of weighted method would make more sense in order to prioritize those data points with less deviation relative to those with larger deviation. What weighted method would make most sense in my case? Thanks a lot for your reply!