darklight03/StackMIAsub huggingface dataset:
I am a graduate student studying wireless perception, and recently I want to carry out liquid recognition. I want to use a speaker as a sound source to generate vibrations (by playing sounds of different frequencies). My idea is that different liquids have different resonant frequencies. When the frequency of the external force is close to the resonant frequency of the liquid itself, the liquid's The amplitude will be larger, so different liquids can be identified. I would like to ask you if my idea is reliable and can you tell me some theoretical knowledge, such as whether the amount of liquid also affects the resonant frequency?
I have been doing some deeper reading on optics out of my interest and one of the most important differences between ray and Gaussian optics is the existence of a non-zero beam waist when a laser beam is focused using a field lens. Most literatures that I have read go over this fact as if it's a common knowledge, but doesn't exactly over why this phenomenon occurs. I understand that focusing to a single point would result in singularity which is physically impossible, but I was hoping if someone could explain what cause the beam waist behavior. Some literatures attribute it to diffraction, but I don't understand what causes this while a Gaussian beam is propagating in vacuum.
I know it happens when the elements on both sides are identical, the more you remove asperities, the more they become like a single substance. But does this happen to the same extent if I take two different substances and start removing asperities? Or maybe close to that... My textbook doesn't explain much about this, it says "By making the surfaces extra smooth, frictional force increases as actual area of contact increases and two bodies in contact act like a single body." Doesn't say anything about the substances taken. Thanks for your precious time.
An example of a non-associative ring R whose non-zero elements form commutative quasigroup (with regard to multiplication in R) without identity is easy to find. I'm looking for examples of a non-associative ring S whose non-zero elements form a non-commutative quasigroup without unity. Put another way: A non-associative non-commutative division ring without unity. 'division ring' in the spirit of 'ring R (associative or not) whose non-zero elements form non-empty quasigroup by means of multiplication in R'. Can you help me ?
In many (biological and living systems) physics courses I encountered the notion that systems operating far from equilibrium are related with more efficiency with regard to their specific tasks. One example I vaguely remember is the comparison of the energy efficiency of ATP to ADP convertion reaction with the efficiency of combustion engines. Unfortunately, I can not think of many specific examples and can only recall this abstract notion of efficiency of systems far from equilibrium. Could someone break this notion down by using many specific examples of simple physical systems, and in each case clearly defining the notion of far from equilibrium and the notion of efficiency ? You could start with the example I mentioned.
I have a camera that gives Azimuth and Elevation of an object with respect to itself (camera). The camera doesn't send image but Azimuth and Elevation data (in float format). The camera doesn't provide range. Is their a mathematical way for me to calculate the range of the said object using Azimuth and Elevation. I wish to use this data received for camera in sensor fusion algorithm along with LIDAR data. For this I need range of the object.
I am currently studying electromigration in liquid metals. According to studies that have been done for electromigration in liquid metals, the metal ions are affected by the electrostatic force and therefore can move to the cathode/anode. The force that moves the metal atoms to the electrode is affected by the charge of the metal ion. However, my professor told me that in liquid state metal atoms should be neutral/not ionized. So how exactly does an electrostatic field affect the metal atoms or cause atomic movement in this case?
Free space is a region in which there is no matter and no electromagnetic or gravitational field. Which means that the resistance in free space is zero, because there is no resisting force and as far as I know, free space is a synonym for "vacuum" and there is no resistive force in a vacuum. So, how is the permittivity of free space, not zero? Permittivity is a property that measures the opposition against an electric field, but there is no resistance in free space, no opposition?
This question relates to the Michelson-Morley experiment and whether anyone has so far proposed an equivalent experiment using aqueous waves instead of optical waves. If it is true that (i) The properties of optical waves and aqueous waves are approximately equivalent and (ii) Nature is consistent in her implementation of traveling waves, then, I believe such an experiment should manifest every characteristic of the Michelson-Morley experiment to some degree of approximation including relativistic effects such as relativity of simultaneity, lorentz contraction and time dilation. Is this a valid assertion? If not, why?
Please forgive me for not having the best grasp on graph theory terminology. I am doing my best. I have a large connected subgraph of a large graph where I want to find, what I am terming the "weak points," of the graph. A "Weak point" exists, in my conception, when given a vertex, there exists at least one single edge among the vertex's edges that can be deleted to create two independent distinct subgraphs. Does this character of a vertex have a name? I can imagine if one must delete two edges to create two independent subgrpahs this vertex would be a "stronger" vertex. Thanks
In an inelastic collision where mechanical energy is not conserved, momentum is still conserved. Should the Earth or the ground be considered as part of the system in order to account for the conservation of momentum? Since there is friction in a collision, is it appropriate to include the ground as part of the system to analyze the conservation of momentum? Are air particles considered to be a part of this isolated system? To clarify I am specifically talking about two vertically-moving objects colliding.
How does a common base transistor amplify current if a small part of its emitter current gets divided into base current and the rest goes to collector current? If the input signal is applied to the emitter part of the transistor then the output current in the collector part should be less than the input one. Then how is the current amplified where the current flow actually decreases rather than increasing?
Is there a notion of a singularity of a real "algebraic variety" which looks locally like a double cone but with a countable infinite number of cones which meet in the same point? A short example or reference would be highly appreciated. I am self-studying algebraic geometry at the moment and the literature/videos do not treat this topic and I am lacking the necessary intuition.
I am very confused about this, are they an excited state of a particle where an electron is excited to an upper energy level, which seems less likely to be the case since the resonant states of particles have different names; or are they the constructive interferences of the wave functions of two different particles, which again doesn't seem likely since as far as I know, one wave function is used to describe a system of particles instead of different wave functions. I am aware of the question, but the answer there doesn't satisfy me
I am beginner to optimization and my question is fundamental. We all know that Static optimization means the design variables/objective function does not vary with respect to time. Dynamic optimization means the design variables vary with time. I need help in organizing the below algorithms/concepts into static and dynamic optimization categories. Ordinary calculus Dynamic Programming Convex Optimization Tabu Search Lagrange multiplier Genetic Algorithm Calculus of Variations Simulated Annealing Linear/Non-Linear Programming Particle Swarm Optimization Ant Colony Optimization First and Second Order Algorithms
Why doesn't a pressure cooker reach a state of equilibrium where the steam passed is constant (assuming the contents of the cooker are maintained throughout the cooking process), but rather, it accumulates pressure until it releases it in the form of a whistle every so often? I don't understand why the pressure "overshoots" and releases more than what would keep the weight open, and then releases more than is needed for the weight to lower. I suspect this has to do with the static friction which needs to be overcome for the whistle to rise being greater than the dynamic friction, or something along those lines.
As the title says, I'm trying to determine numerically when an n-DOF oscillating system (linear or nonlinear) subjected to forced base oscillation reaches the steady state solution. Is there an energy component (or another global parameter) that converges to a single value when the steady state is reached? I have the time series of the position and velocity of every mass and the base oscillation.
Recently while experimenting with force experienced by current carrying conductor, I came across a abnormality in the horse shoe magnet, due to which the direction of force on the current carrying conductor by the Flemings Left Hand Rule was false. I noticed that when i kept a compass near the heads of the horse shoe magnet, the needle pointed from North Pole to South Pole of the magnet. But when it was kept between the two hands, it pointed from South Pole to North Pole. I dont think it is theoretically possiblle that magnetic field is going from North to South outside the horse shoe whereas it is going from South to North between the two ends of the horse shoe. Please explain this.
There are certain complex functions which lack a proper denominator corresponding to which poles can be found for the given function. For example , the gaussian function, the frenel functions are some of the popular functions lacking any denominator, in the complex plane . So , as a result of those function lacking any pole , I am wondering how to evaluate their corresponding improper integrals using contour integration (complex analysis). Is there any way by which a denominator can be generated assuming certain conditions for those functions lacking denominator? I really want to clear the doubt regarding this ...All of yours opinions would be highly appreciabble in my regard. Thanks a lot in advance .
I have a question about degenerate electrons in white dwarfs. So, as far as I know, when the gas contained in stars is compressed so much, the electrons start to fill the lowest energy level and then, for Pauli's Principle, they continue to fill up incresing energy levels up to a certain level. As you can read here http://astro.vaporia.com/start/electrondegeneracy.html, "During compression, as electrons take on momentum, they gain too much to maintain a nucleus orbit, and they travel freely through the material rather than remain with a single nucleus." I did not understand this last statement. Does this mean that the electron become free? Or they are still bounded to the nuclei? Thanks for the answers
It is well known that the method of image charges is not always applicable, so I was wondering: is there an analytic way to calculate the electric potential for a point charge interacting with a perfectly conducting, neutral (edited) metallic disk using image charges? If it can be calculated or not, for what reason? Even if it could be solved, I don't think the method conforms to that of a conducting sphere, so I would like to know (if there is one) an analytical method that would allow it to be calculated.
When a satellite is revolving around a planet with an orbital velocity in presence of air resistance, the satellite's Kinetic Energy keeps on increasing as it falls down. The resistive force is trying to decrease the speed and the gravitational force cannot change the speed (or Kinetic Energy) as it's perpendicular to the velocity. Or, am I wrong and gravity can actually change K.E. even if it's always perpendicular to velocity. In the Free Body Diagram, I see no force acting along the velocity that can increase the speed of the satellite.
I and some classmates are recently teaching ourselves the famous book Foundations of Perturbative QCD by John Collins via a form of regular peer reading group. We find that exercises in this book are really worth working on. But, as a group of relatively junior students, we are hesitating to go deeper before finding a way to verify our answers. One obvious solution must be to consult some more senior researchers. But, other than that we want to know whether there exists a document of solutions to this book, so that at least we can self-verify even if we fail to find such a senior mentor.
The tangent plane at a point of a hyperboloid meets the hyperboloid in the two generators through that point. However, a tangent plane is defined as the locus of all tangent lines at a point on the hyperboloid. Now, since generators lie completely on the surface they can't be tangent lines to the hyperboloid. Then how is it possible that the tangent plane contains the generators that intersect at that point?
What's a safe, easily executable experiment to confirm that quantization of light occurs directly to the retina. We know that light is quantized when projected on to a surface, or on to an inanimate detector, then the surface or the detector observed. An eye can detect a single photon. This means we should be able to quantize light such that a single photon lands on the retina of the left eye or of the right, and the observer confirm it is seen in only one eye. What's a design for this experiment?
From my understanding self-energy is the energy required to put charges in a certain charge distribution and interaction energy is the potential energy caused by the interactions between particles, but to me it seems like there isn't really a big difference between them and this post What does electrostatic self-energy mean? basically talks about them like they are the same thing. My book says the total energy is the sum between the interaction energy and self-energy. I'm very confused.
From what I understand relativity predicts that outside observers would never observe external objects actually crossing into the event horizon, due to time dilation. How does that can reconciled with the fact that the Schwarzschild radius is largely dependent on black hole mass? Then, does this imply that one can never observe an increase in the radius of the event horizon? This seems wrong to me, as there are different size black holes, and I'd like to know what I am missing.
I am trying to say in good quality English that a certain idea which was implemented is currently used way beyond the scope it was intended for. It was a gap-filler which we are now basing our entire solution and this is going to be unsustainable. I am trying to write something like "This architecture has exceeded it's original ____ and needs major refactoring" I know there's a word exactly for this... I keep coming up with "premise" or "precinct" (I know the word I am looking for sounds something like these, not saying they are applicable). I've already used "purpose" a lot, in a different context, and I need to avoid using purpose for this statement to prevent confusion.
Suppose a car is at rest and you apply the accelerator, then the wheels are applying a horizontal force on the road so according to Newton's third law an opposite force (friction) pushes you forward. From what I understand no matter how much force you apply (hit the accelerator) the maximum force that can push you forward is the limiting friction. But then since the car is going with an acceleration forward friction should again act backward and there will be no net force, so the car doesn't move. How is this possible?
It's well-known that given a sentence independent of a system of axioms, we can consistently extend the system by appending either the sentence or its negation. However, if a given theorem can be deduced in each of the two systems, then we have a proof of that theorem. We don't even need to prove independence, because given any sentence, either it or its negation is consistent with a given system, provided that the original axiom system is consistent. I'm simply wondering whether there's a specific example of that proof technique having been used.
An observer near the event horizon of a black hole will experience an extremely strong gravitational field. Due to the principle of equivalence, this observer cannot locally distinguish between this strong gravitational field and the experience of being in a highly accelerated frame. As a result, the observer will detect radiation or temperature in the seemingly empty space around them, as predicted by the Unruh effect. This radiation can escape to infinity being near the event horizon not inside the black hole, and is what we refer to as Hawking radiation.
I tried to understand the physical interpretation of uniform continuity, and saw different graphical interpreation in Wikipedia. At the end, I have concluded that functions which are uniform continous in a set, also have finite derivative in all the set and its boundary. Is this interpretation right? I don't want to be rigourous at all, but if you can provide some proff or counterexample, it will be great. Thanks!
Normal measurements of compressive strength work by compressing a sample with an hydraulic press and see when the sample deforms plastically or cracks. Now if pressure is applied on the surfaces of the sample that aren't in contact with the hydraulic press, will the compressive strength (as seen by the hydraulic press) increase ? If yes, will that increase be exactly the external pressure or lower or higher? I feel like the compressive strength as seen by the press must be higher because the pressure on the "sides" will prevent the material from going outwards thus deforming or cracking. (Imagine a cylindrical sample is being pressed) Am I missing something ?
I was wondering if someone can explain simply why phase changes are isothermal processes? I am studying hydrology and some of our material about snowmelt has to do with phase changes and in this example, water retains a constant temperature when melting/freezing, or boiling/vaporizing. I was wondering why, as the ice melts, why does the temperature not increase as it is changing phase? I am just wondering if there is a chemical/molecular reason that better explains why the heat energy is no longer warming the ice as it changes phase. Like, is all the energy directed to separating the bonds and cannot go to heating? My background is aerospace/mechanical engineering so I have some thermo experience but the more simple the explanation the better. :)
Consider a piston such that it is in mechanical equilibrium with its surroundings. If I pull the piston (reversible work) then the work done by me would be positive. If I push the piston, again work is done by me. However, in one case positive work is considered to be done on the gas inside piston, while it is negative in the other case. If I pull the piston, negative reversible work will be done on the gas -- does it mean that the gas is working on me? I know that I must be making a mistake, but what?
What are some good entry points into physics? I'm wanting to eventually be able to understand some more abstract concepts like quantum physics but understand that is a very long way away. Just been spending far too long trying to understand things above my pay grade. I'm pretty sure I remember linear algebra being something I should read up on, what are some good books on that subject? What are some other good books that would be entry points? I'm wanting to eventually be able to understand some things like Planck area and a lot of concepts related to entropy. I would consider myself intelligent but not well read as I've slacked on learning since high school. Any help is much appreciated!
I am working through Srednicki's "Quantum Field Theory" and am at the chapter on the Minimal Supersymmetric Standard Model (MSSM). In answer to why two higgs superfields are needed in the MSSM model, Srednicki's solutions say that "...the superpotential cannot depend on hermitian conjugates of [super]fields." In trying to think through why this is, the best I could come up with is that any Yukawa term in the superpotential with a hermitian conjugate could either ... make a vector superfield and thus not something that would be in the superpotential and/or it would be a term that wouldn't be holomorphic (though I have to be honest, that my knowledge of holomorphism is very limited and shaky at best).
Using induction on the complexity of formulas, let's assume that in every proper non-empty initial segment of a propositional formula, the number of left parentheses is greater than or equal to the number of right parentheses. Note: A proper initial segment of a propositional formula is an expression that starts and continues with the same symbols as but does not include all symbols of . Any thoughts?
When a capillary tube is inserted into a large body of water, there is an increase in potential energy (PE) of the system. This is because the increase in PE of the rising water in the capillary is greater than the loss of PE of the body of the water. The increase in height of the capillary water is greater than the loss of height of the body of water, and the same mass is involved. Is an empty capillary tube really a source of potential energy?
Simple question, but I can't find any answer around. If a pipe turns, aka is not straight, the length of the pipe (in order to calculate the resonance frequency) is given by the length of the imaginary line connecting the centers of the circular section of the pipe, by an imaginary string of zero width that connects the two extreme of the pipe, or by which other measure? For a straight pipe is easy, but I can't find any information on what happens when it bends. Silly question for the standard here, but I don't know where else to ask Thanks a lot
I've come across the expression "head(s) and tails above" (the rest, the competition etc; different from something like "can't make head or tail of something" i.e. can't figure it out/understand). I can't find information about this. It seemingly means completely. Could you confirm its meaning and explain it a bit? Is it rare, is this expression recent and is it restricted to or typical of specific regions (Canada?)?
I have been thinking about how physics has evolved since the time of Galileo . Back then physical laws could be describe using axioms which could be comprehended by anyone who reads them. But currently physics is done in a whole different manner. The laws are written mathematically. The language of mathematics is deeply encrypted in the study of physics. For example, the theory of general relativity requires the idea of tensors, black holes are deeply mathematical and so on. I just wanted to know why physics is done using mathematics? Cant it be done without mathematics - for instance, by only doing only experiments?
Vogel's method selects the corresponding variable through a penalty. There is a penalty for each row and column and is the subtraction between the two lowest costs (in absolute value). We must select the highest penalty and then the lowest cost in the row or column of this penalty. I understand the second step (if you want to reduce the cost of the problem, you select the lowest cost of the row or the column), but not the first. I don't understand why we have to do the subtraction between the two lowest costs and, then, select the highest penalty. Can someone tell me what the explanation is?