Exchange Definition and 245 Threads

Hello, I arrived here following links to "heat exchange". I've got a small (200amp) tig welder and would like to move up to a water cooled torch. I'm building my own cooler in my workshop. I'm challenging myself to fit a cooler into the smallest package possible, the only limits being my...

Consider a system of two bosons with spin, say photons. The wave function must be symmetric under the exchange of the two particles. For example, |psi> = |up> |down> + |down> |up> So far, so good. Now let us measure the spin of the particles, and let the outcome of the measurement be that...

Homework Statement Let E be the exchange matrix (ones on the anti-diagonal, zeroes elsewhere). Suppose A is symmetric and positive definite. Show that B = EAE is positive definite. Homework Equations The Attempt at a Solution I've tried showing directly that for any conformable vector h...

hi, the standard (?) explanation for particle exchange to produce repulsion and attraction is at: http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html this seems to me to have two problems. 1.) in the case of repulsion beteen two electrons, the direction has to be...

Could someone explain me an elementary introduction to this phenomenon ? i know that it is produced whenever an ANTIFERROMAGNETIC and a FERROGMAGNETIC materials are put together , however my doubts are - is this 'exchange bias' produced by any spin interaction ?? - i can see the figures...

Hi, I am involved in a project that cools outside air to underground temperatures at 6' below ground in Florida soil. we are using thin wall PVC @ 4" diameter. i am looking for an equation that will tell me how long to make the pipe and what the ideal cfpm should be to achieve desired...

. hi everyone here , i have a problem about the exchange energy . IN quantum mechanics, there is a example how to solve eigenvalue and eigenfunction of helium within the framework of perturbation theory . when two electrons are in different eigenstates,the first order correction of...

Just looking through some old papers and found a problem that I don't know how to solve. Two identical 1.0-kilogram blocks of copper metal, one initially at a temp OC and the other initially at a temp of 100C are enclosed in a perfectly insulating container. The two blocks are initially...

It seems to me that the physics is the same they are all due to the exchange of virtual photons between two particles

When Empathizing, one puts oneself in another's shoes (colloquially speaking). The magnitude of the wave function corresponding to identical particles is invariant under the exchange operator. This exchange interaction; one might say that identical particles are "empathizing" with one...

How does the exchange of photons/virtual photons give rise to the electrostatic or electromagnetic force? Why do like charges repel and opposite charges attract?

Has anyone heard of this title or seen the documentary. Well I was introduced to it by my roommate. I found it very interesting how one sided University's are, the majority of faculty hold very liberal views, I tested this at my own school (University of Washington) and based on my experience i...

I know there is already a post on this, but I just wanted to make a point. I live in California, so obviously there is a great deal of controversy here by the coast and especially where I am (a small conservative community) whether or not warming is legit (long story short, I believe...)...

exchange forces have always confused me. I get the feeling they're made up to explain forces. The exchange of a photon between two electrons makes some sense to me. Conservation of momentum alone would make them repel each other. It makes some sense that on a larger scale this "force" would...

Hi, Was doing a bit of work the other day and I was looking at collisions. Thinking about real collisions compared to ideal ones and the thing in particular which stands out is that often when two vehicles (for example) collide the striking vehicle will continue to travel some distance in its...

is anybody here from Russia? I ask as I'm planning on doing some type of exchange program there, and am looking for schools that have strong physics programs. i'm hoping to go to a school near a city so I get a better chance to experinece russian life.

Hey! Could someone please explain to me what the exchange integral exactly represents? I understand the coulomb integral and the overlap integral, they have nice classical analogs. But there doesn't seem to exist a classical analog to exchange. Thanks

I ran some simulations with a two mass-three springs oscillator. I found that one mass would oscillate for a while and then almost stop. When that happened the other would start moving back and forth. Is there a way I can predict at what rate the masses will exchange energy?

Well its not really a homework question but I have looked through the tutorials and am still at a loss. Homework Statement During weak interactions the particle exchanged is either W- W+ or Z0. The thing is, I get confused which weak interactions involve W- and which involve W+. I know...

Deuterium is heavier then Hydrogen so a metal bonded to H vs. C can be determined by isotopic exchange and then using Infrared Spectroscopy/mass spec. But how do you replace hydrogen with deuterium? a.Dehydrogenation and then add deuterated solvents (heavy water or CDCl3 ..deuterated...

Can gravity be explained by exchange interactions? I am supposed to give a presentation on it, so some explanation as to why or why not would also be very much appreciated. Thanks very much in advance.

Guess what? I made conversation hearts! :!) INSTRUCTIONS: 0) Quote this post and use only the text following the dotted line below (don't forget to delete the ending [/quote'] tag). 1) Fill out the TO: and FROM: fields. 2) I included three lines for your message (you don't need to use all of...

i would like to know more about the heat exchange in mixtures and thermodynamics example would be like: How much heat energy is required to change? a) 2.0kg of ice at 0 C to water at 0 C? b) 500g of water at 100 C to steam at 100 C?

I understand (vaguely) how momentum is exchanged via virtual photons in electromagnetic interactions. But how do the changes in kinetic energy occur? For instance, a proton and electron are at rest separated by a distance x. The proton emits a virtual photon and recoils in the direction of...

All the places I've searched I find that the change in the internal energy for the adiabtic process is dU = C_V\,dT But I don't understand why they use C_V, neither the volume nor the preassure is constant during the adiabtic process.. I know that dU = C_V\,dT = C_p\,dT - p\,dV...

I noticed someone posted on the internet (not on PF of course!) a largely senseless attack on science which contains a discussion of quantum mechanics and the view that neutrons change into protons and protons into neutrons in what they called a ceaseless exchange of identity. I think it's...

Hello, although being graduated in physics (but not being an expert on QED) I find myself embarassed in trying to explain in very simple terms how the electrostatic force arise from the exchange of virtual photon. Especially when it comes to actually reduce all calculations to the expected...

I'm trying to understand the Hartree-Fock mathematical formulation I understand the Coulomb operator, but I don't understand the exchange operator: \hat{K_{j}}[\Psi](\textbf{x})=\Phi_{j}(\textbf{x})\int d\textbf{x}'\frac{\Phi_{j}^{*}(\textbf{x}')\Psi(\textbf{x}')}{|\textbf{r}-\textbf{r}'|}...

I've been reading Giancoli (Physics for Scientists and Engineers, 3rd Ed) and Griffiths (Intro to QM). There seems a contradiction on the applications of the Energy-time uncertainty principle between the two. Griffiths claims that energy is always conserved, even though mathematically...

hello all I never really understood the future exchange Market. Can anyone explain it to me in detail, any information would be helpful? thank you

why is it acceptable to assume any heat exchanged with the surroundings of a system is a reversible heat exchange? The only explanation I can find is that it's because the surroundings are essentially unchanged by the heat they absorb...but I don't understand that as an explanation. I take...

For a hydrogen/deuterium exchange experiment, the protein of interest is first incubated at pD = 7, after which it is quenched at pH = 2-3. Why it the exchange done at a neutral pD and why has the exchange of hydrogen atoms a minimum at pH 3?

In Yukawas model the force between nucleons comes from the exchange of a pion. How precisely does this lower the energy? Has it something to do with confinement energy? I know an exchange force can be understood in terms of a momentum exchange by the force carrying particle. But there must...

When N2 and H2 are reacted in a bomb calorimeter to form NH3 the temperature of the bomb calorimeter and the water it contains increases. Is the energy required to break the bonds in the reactants greater or less than the energy released during the formation of the bonds of the prouducts. I...

I never really understood the stock exchange. :cry: Can anyone explain it to me in detail :-p

I was wondering if their is a critical distance for quark exchange. say you have a proton and a neutron in the nucleus. When the quarks get very close to each other they exchange from the proton to the netron. they can no longer tell the difference between its up quark and the neutron's up quark...

I can't solve this problem. Could anyone help me? A piece of metal with a mass of 2kg and specific heat of 200J/kg C is initially at a temperature of 120 C. The metal is placed into an insulated container that contains a liquid of mass 4kg, a specific heat of 600J/kg C, and an initial...

Hey guys, please help. Two people, one of mass 65kg and the other of mass 40kg, sit in a rowboat of mass 85kg. With the boat initially at rest, the two people, who have been sitting at opposite ends of the boat, 4.0m apart from each other, exchange seats. How far will the boat move? and in...

As far as I can see, the exchange particle involved in gravitational forces is the graviton. However, in the markscheme for both the original and revised EDEXCEL A-Level Physics PHY3 Topics Paper (topic C) it states that it is the photon. Which is correct, or are both correct? Why is there this...

Economics is also a social sciences branch. So, I post this here but if moderators find that my question is not appropriate to stay here, please move it to the place where it should be,Thank you very much, Very short question, that has anyone of you, gurus, senpai, etc any experience in...

Mind to Mind: Mr. Dennett & Mr. Gautama Exchange Ideas (NOTE: The main body of this thread, though written as a fantasy :cool:, prepares for earnest “test questions” posed at the end of the thread.) Good day ladies and gentlemen, welcome to Mind to Mind! Sit back and enjoy as we utilize...

Suppose two particles bound by electromagnetic interaction, kind of hidrogen atom. How do you calculate the number of virtual photons exchanged by unit of time? Has this frequency of exchange some meaning in usual textbooks?

How much US dollars can I get if I have 10 000 TaiWan Dollars?

I would like to exchange books on nanotechnology and modern physics Popular science books only I am too young for all that math if you have a book had read already and it's just laying around contact me here please I live in Israel

Here is a horribly misguided theory from my youth. I polished it up a bit and gave it a name. If anyone wants this theory, they can have it. MicroElectroMagnetoValence Theory Tenets:[list=1] The fundamental electric and magnetic charges are 1/6 of the elementary electric and magnetic...