Exchange Definition and 262 Threads

  1. joshcitylife

    New member

    Hello im Josh I found this site via google. I like to exchange ideas in order to create a better place for my kids and yours!
  2. E

    Thermodynamic equilibrium for systems only open to particle exchange

    I am only interested in the initial equilibrium conditions, and I am struggling to convince myself whether that should correspond to the equality of chemical potentials for H2 or an equality of temperatures as well. My work is as below: We take both gases as simple ideal (this is only relevant...
  3. archeryemily9085

    B Filling a bathtub (Hot water to cold water exchange)

    Hey there, I honestly don’t know if this is the right place for this, but I figured I would ask. lets say you are going to take a bath, but someone just took a shower and you know your hot water heater will be running low on the goods. Just for arguments sake, let’s say you have just enough...
  4. D

    A Heat exchange in a thermal storage based on phase change materials

    Hello, I want to model a thermal battery based on phase change materials (PCM). It is a plate heat exchanger immersed in a PCM bath. The diagram is given in the attached file. I want to determine the temperature at each moment and from everywhere in the battery. The hypotheses are the...
  5. V

    B Heat exchange after thermal equilibrium

    In screenshot below, systems A and B are separated by an adiabatic wall initially while each of them exchanges energy with system C via a diathermic wall. Once A and B reach thermal equilibrium with C, then A,B are allowed energy exchange via a diathermic wall, and energy exchange between A and...
  6. J

    I Particle exchange explaining attractive forces

    I understand, and have unwillingly come to terms with the fact that virtual particles can carry negative momentum. This explains how momentum can be conserved in attractive forces via particle exchange. I have a problem with this that I cannot reconcile...wouldn't this imply that as a particle...
  7. shivajikobardan

    Comp Sci Diffie Hellman Key Exchange Algorithm? (x,y value)

    I'm not asking it from "will it be secure" point of view, rather I'm asking textbook kind technically correct or not. This is the algorithm (in the 3rd step of right figure, it should be generate y, typo) I took p=23,g=5. And picked x=4,y=5 I got the secret key as 12 and both got 12, so it...
  8. S

    Stripping ions from exchange resin

    I want to strip the hydrogen ion from a cation exchange resin. Would it be feasible to do this using hot water? I've tried using water at somewhere above 130 degrees Fahrenheit I believe, but I didn't see any immediate decrease in pH. I believe the resin uses polystyrene sulfonate. Should I use...
  9. V

    B How does exchange of elementary particles result in a force?

    Homework Statement:: I came across the following in an online article. I am unable to understand how these elementary particles cause a force to exist. "Each of the four forces results from the exchange of force-carrier particles.". Above statement is taken from...
  10. pdorton89

    Need Help with Heat Exchange Calculations for Cosplay Suit Idea

    Hello, I am trying to figure out if the investment into a watercooling system in a Cosplay suit would be worth it. I plan on using a water loop made by taking a "CoolShirt" https://coolshirt.com/product/white-coolwater-shirt/ and running water through it either from an ice bath in a sealed...
  11. Samama Fahim

    I Deriving the Commutator of Exchange Operator and Hamiltonian

    In the boxed equation, how would you get the right hand side from the left hand side? We know that ##H(1,2) = H(2,1)##, but we first have to apply ##H(1,2)## to ##\psi(1,2)##, and then we would apply ##\hat{P}_{12}##; the result would not be ##H(2,1) \psi(2,1)##. ##\hat{P}_{12}## is the exchange...
  12. K

    I Equilibrium equation if the barrier allows particle exchange

    "... two physical systems [seperated by wall], A1 and A2. A1 has ##\Omega_{1}(N1,V1,E1)## possible microstates, and the macrostate of A2 is ##\Omega_{2}(N2,V2,E2)## " "... at any time ##t##, the subsystem ##A_{1}## is equally likely to be in anyone of the ##\Omega_{1}\left(E_{1}\right)##...
  13. G

    Functional Analysis exchange year at Imperial

    Hey, I would like to do an exchange year at Imperial. I would like to follow as a physicist the Functional Analysis course. However, I have not heard the best things about this peculiar course. What is the audience opinion on that?
  14. UFSJ

    A Magnetic exchange interaction by first principle (Blume-Capel model)

    Hi guys. I work with statistichal mechanics, applying classical spin models, as Ising model. I'm trying a collaboration with a colleague that works with first principle calculations. Does anyone know how to calculate the exchange interaction and anisotropic constant (of the Blume-Capel model)...
  15. S

    HVAC Attic to Pool Heat Exchange, will car radiator collect heat?

    My attic gets very hot even with the exhaust fan I installed. I would like to move than heat to my swimming pool. I currently have a FAFCO solar pool heater where the pool pump pumps water up onto my roof and thru the 12' long solar panel and down back into the pool. I would like to free up roof...
  16. F

    Neuron's location and signal exchange with the rest of the body

    Hello, Just checking that my understanding is correct: the nervous system is formed by the central nervous system (CNS), which comprises the brain and the spinal cord, and by the peripheral nervous system (PNS) which bring signals from and to the CNS from and to the rest of the body. Both CNS...
  17. P

    I Are Virtual Exchange Particles a Valid Concept in Understanding Remote Forces?

    Such particles are virtual, but it should be possible to associate a basic idea with them, as this is the foundation of calculation methods. I think the concept of vacuum fluctuations in the form of virtual, fluctuating pairs of particles is something else. Is the idea of virtual exchange...
  18. Rzbs

    I Electron correlation vs electron exchange

    What is the difference between electron correlation and electron exchange? Which of them is due to the spin of electrons and which is due to charge of electrons?
  19. A

    I When does the exchange operator commute with the Hamiltonian

    I am attaching an image from David J. Griffith's "Introduction to Quantum Mechanics; Second Edition" page 205. In the scenario described (the Hamiltonian treats the two particles identically) it follows that $$PH = H, HP = H$$ and so $$HP=PH.$$ My question is: what are the necessary and...
  20. sophiatev

    I Significance of the Exchange Operator commuting with the Hamiltonian

    In an Introduction to Quantum Mechanics by Griffiths (pg. 180), he claims that "P and H are compatible observables, and hence we can find a complete set of functions that are simultaneous eigenstates of both. That is to say, we can find solutions to the Schrodinger equation that are either...
  21. bob012345

    A Coulomb and Exchange Integrals

    Summary: I'm looking for a table of Coulomb and exchange integrals for Lithium and beyond. I'm looking for a convenient table of Coulomb and exchange integrals for Lithium and beyond. I've looked everywhere and I find integrals for J,K 1s, 2s or 1s,2p for Helium. Does anyone know of a...
  22. ValeForce46

    Two objects exchange heat through a cyclical thermal machine

    This is how I solved part a) : ##Q_1=C\cdot (T_1-T_i)## This quantity is negative because object 1 loses heat. (positive for the machine) ##Q_2=C\cdot (T_2-T_i)## This one is positive because the object 2 absorbs heat.(negative for the machine) Then the exchanged heat FOR THE MACHINE is...
  23. O

    B Photon exchange in molecular bonds

    So a photon is absorbed into and emitted from electrons, causing the electrons to jump energy levels around an atomic nucleus. And enough energy absorbed into the electron will cause the electron to break from the atom altogether. My question is, where does this energy that enters the...
  24. sww_world

    Heat Capacity energy exchange problem

    Givens for water: m: 0.250kg of water TW : 95°C C=4180 Givens for mug: m=0.085kg TM : 19° c=107 Required: final temperature of water Analysis/Solution: Qreleased+Qabsorbed=0, q=mc▲t mw*cw*Tw + mp*cp*Tp = 0 (0.250)(4180) (T2-95) + (0.085)(107)(t2-19)=0 1045(t2-95) + 9.095(t2-19)=0...
  25. P

    I In QFT people exchange electrons during touching?

    Does in QFT static electricity work classically or is there a more fundamental explanation?
  26. S

    Prove that the exchange operator is Hermitian

    Homework Statement [/B] Let P be the exchange operator: Pψ(1,2) = ψ(2,1) How can I prove that the exchange operator is hermitian? I want to prove that <φ|Pψ> = <Pφ|ψ>Homework Equations [/B] <φ|Pψ> = <Pφ|ψ> must be true if the operator is hermitian. The Attempt at a Solution [/B] <φ(1,2) |...
  27. C

    I Phenomenological potentials and exchange of force carriers

    Consider a proton-neutron system. Phenomenlogical nucleon-nucleon potentials contain exchange forces terms (Majorana, Bartlett and Heisenberg terms), which are linked to the symmetry of the state w.r.t. (for example) the exchange of isospin (i.e. charge). On the other hand proton and neutron...
  28. C

    I Strong force as exchange of mesons, or of quark and antiquark

    The (residual) strong force between nucleons can be desribed as - The exchange of a meson (from a nucleon to the other), as in picture b) - The exchange of a quark and an antiquark: in picture a) one nucleon "gives" a quark and receive an antiquark and it's the opposite for the other I do...
  29. Andres Padilla

    Why this special case occurs in an exchange of heat

    Homework Statement Hello. First of all sorry about this question, it has to do a little with heat transfer from engineering. This situation is not real, I was working in a proyect and this doubt came to me. I have a heat exchanger of parallel tubes. Water flows in a tube and oil flows in...
  30. N

    A Electron-Hole- or Many-Electron Exchange Interaction

    Hello together, I'm interested in the electron-hole exchange energy. I would like to see how and have a proof why electron-hole exchange works. Is it symmetric or antisymmetric? More specific, I would like to have a proof that exchange with paired electrons in a molecule can be neglected...
  31. A

    I Do particles in the universe exchange gravitons with each other?

    Does each and every, say, proton, neutron and dark matter particle (DMP) exchange gravitons with each and every other proton, neutron and DMP in the universe? (Sorry if this question has been posted to the wrong forum. Advice re correct forum would be appreciated.) Art
  32. sophiecentaur

    Confusion about ion exchange water softener

    I am about to have a water softener installed and I thought I should learn a bit about the Chemistry involved. There is loads of advertising blurb on the Web but very little precise Chemistry. I am sure someone here can help me with this. The basic softening process is fair enough with sodium...
  33. dRic2

    Calculating Heat Exchange Surface for Fluid Flow

    Fluid comes in at ##T_1## and comes out at ##T_2## and I know that heat is exchanged with steam at constant ##T_{steam}##. If I want to know the Surface of the exchanger then ##US(T_{steam}-T_{fluid}) = \dot m_{fluid} cp_{fluid} (T_2-T_1)## My question is, since ##T_{fluid}## changes, which...
  34. Luke Strand

    Finding Initial Temperature Entropy and Heat Exchange

    Homework Statement A 2.45 kg aluminium pan at 155 C is plunged into 3.58 kg of water. If the entropy change of the system is 162 J/k, what is the initial temperature of the water? Homework Equations Q = mcΔT ΔS=mcln(T_2/T_1) Q_water + Q_Aluminium = 0 c water = 4184 J/kg*K c aluminium = 900...
  35. A

    Eigenvalue of Exchange Operator in Hartree-Fock: 2e-

    Homework Statement Homework Equations The Attempt at a Solution [/B] ##\hat{S}_1.\hat{S}_2 = (S(S+1) - S_1(S_1 + 1) - S_2(S_2 + 1))/2## therefore singlet: ##\psi_s = \frac{\phi_a (1)\phi_b(2)(\alpha(1)\beta(2) - \alpha(2)\beta(1))}{\sqrt(2)}## So for singlet, ##\mathcal{V} = -\frac{K...
  36. P

    Carnot Cycle: Analysis of Energy Exchange

    A refrigerator operates on a Carnot cycle. In this cycles, it absorbs 120 J of energy at a temperature Tc while 300 J of work is done on the gas undergoing the cycle. How much energy is exhausted as heat during this process? The answer is 420 J. I am unsure of where to start for this...
  37. M

    Physics New to Spectroscopy? Let's Connect and Exchange Ideas!

    hi friends, I am new to this forum and to this domain as well,i am basically a networking/IT guy, i am looking to do some project which is involving spectroscopy to find chemical composition in different elements. As i am new to this domain,i don't know how i can find a friend/guide probably...
  38. S

    A Relative sign in diagrams for ##Z##-boson exchange for ##WW## scattering

    Consider the scattering process ##W^{+}W^{-} \to W^{+}W^{-}##. This process is mediated in the Standard Model by 1. a four-##W## scattering, 2. ##Z##-boson exchange, 3. Higgs exchange...
  39. rachel6589

    Calculating Heat Exchange for a Water Pump

    Homework Statement A pump, operating at 10 W, is used to raise the pressure of a stream of water at 2.5 mol/s from 1 bar to 2 bar. At steady state, if the water temperature should remain constant at 25oC, how much heat exchange between the pump and its surroundings is required? Note that 1 bar...
  40. throneoo

    I Defining exchange statistics of anyons in terms of Berry phase

    In 2D, if we define exchange statistics in terms of the phase change of the wavefunction of two identical particles when there are exchanged via adiabatic transport (https://arxiv.org/abs/1610.09260), we would discover that this phase can be arbitrary due to the topology of relative...
  41. Carlos de Meo

    Heat exchange, emissivity and reflectance

    Hi Guys I´m studying the heat exchange problem in furnaces and, to begin with, i started with Incropera´s book. One thing is actually driving me crazy On the last part of this exercise´s solution (part 3), the physical principle involved is not very clear to me. To calculate the absorptivity of...
  42. Ben Wilson

    I What mediates the exchange force?

    In many-body theory for electronic structure, fermions experience a force resulting from Pauli Exclusion. So by extension, would quarks and other subatomic fermions experience this force? If so, what is the "high energy" physics side of the story to forces arising from exchange rules? Is it a...
  43. Ian Baughman

    Heat exchange in an isolated system

    Homework Statement In a container of negligible mass, equal amounts (in weight) of ice at 0°C and steam at 100°C are mixed at atmospheric pressure. Assuming no heat exchange with the surroundings, what is the temperature when the system reaches equilibrium? What are the fractions of weights of...
  44. A

    A Difference between Hubbard and Heisenberg-model

    Hi, I read a chapter about the Heisenberg-model, and then something about the Hubbard-Model. The Heisenberg-model just shows, that neighbouring spins allign antiparallel if J<0. The Hubbard-Model says, that there is a hopping probability t and an Coulomb replsion, so that a material becomes...
  45. Vibin Narayanan

    B Gauge Boson Exchange: Do Particles Influence Each Other?

    Do a particle influence another particle by exchange of gauge bosons? If so, how?
  46. wolram

    Xmas Card Exchange: Send & Receive Cards

    I am very happy to receive and send Xmas cards:biggrin:. I still have some addresses, so please let me know is you want a card from me.
  47. CassiopeiaA

    I Exchange of photons inside atoms

    I was reading Feynman Diagrams and stumbled upon this query: If the electrons and protons interact by exchange of photons, does the electron inside an atoms also interact with the nucleus with a similar kind of exchange?
  48. OMANII_93

    Calculating Heat Exchange Requirements for Ethanol Condenser

    Homework Statement Hi, I need someone to help me with this question. I tried to find the answer for two weeks I could not finde it. Anyone with the required experience can help! I will be so grateful. Question: A shell-and-tube heat exchanger is to act as a condenser: saturated ethyl alcohol...
  49. D

    I How do Particle Exchange Forces Create Attractive Forces?

    So sorry to post what seems to be a well worn question. So the 4 forces of nature work by "particle exchange" ? Yes we understand the maths of "Fields" and we have the elegance of Maxwell and Newton/Einstein and these mathematical descriptions lead us to force exchange particles which can...
  50. T

    Linear Algebra, forcing a row exchange.

    the answer key said d is supposed to be 10. but there's a way to evade that row exchange. 1st picture is the question and the 2nd picture is the elimination steps.
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