Transport Definition and 239 Threads

I am little bit confused about derivation for Boltzmann equation for electron look at this link http://relativity.livingreviews.org/Articles/lrr-2008-10/articlesu25.html which is final boltazmann equation ?

Hi all, I want to learn Quantum Transport materials . I would like to know some good material to start with and also I want to learn NEGF formalism. please suggest me some good books that teach from fundamentals in these areas.. Thank you ...!

I have this equation ux(x,t) + c(x)ux(x,t) = 0 x>0 I want to obtain information on how the initial input uo(x)=u(x,o) would deform when the sound speed is not constant. c(x) is the sound speedi wanted to start this by finding a DE for the level curves x=X(t) so that i can solve in terms the...

am given a scaled transport equation ut(x,t) + ux(x,t)=0 x>0; t>0 u(x,0)=0 x>0 u(0,t)= sint t>0 how can I begin to find a solution in the quadrant {x.0,t>0} to this problem, am really struglling:(

Published values for the room temperature thermal conductivity of graphene vary from ~2000 W/m*k to 5600 W/m*k, for freely suspended samples. The large discrepancy shows the sensitivity of graphene to lattice defects (contact with substrate, edge defects, etc.) Thermal conductivity increases...

Hi everyone, I am currently undertaking my honours year in physics focusing on atmospheric physics. I am wondering if anyone knows where I can get a model to determine how much energy is moved to the top of the troposphere by deep convective "hot towers". I wish it was as simple as...

From the Wikipedia article on the Riemann curvature tensor: The last sentence assumes that ##\tau_{sX}^{-1}\tau_{tY}^{-1}\tau_{sX}\tau_{tY}## returns Z back to x0. It isn't obvious to me that this should be true. My guess is that this is true because X and Y commute, but I can't think of a...

I am starting to work with the high temperature superconductor BSCCO (Bi–Sr–Ca–Cu–O). I have read that the carriers of superconducting current is hole pairs. (As opposed to electron-pairs in normal superconductors) I am trying to understand how the transport would work. If I contact it with...

Say we have an electron traveleing in a crystalline conductor. It can scatter off of defects such as vacancies, interstitial atoms, grain boundaries, etc. Is there a way to quantify the relationship between conductance and defect density? I.e., if I want to build a 2D crystalline...

I have this question on the calculation of the geometric phase (Berry phase) of a parallel transporting vector over the surface of a sphere, illustrated by Prof. Berry for example in the attached file starting on page 2. The vector performing parallel transport is defined as ψ=(e+ie')/√2...

Given a curve c(τ) with tangent vector V, a vector field X is parallel transported along c if \nabla_V X=0 at each point along c. Let x^\mu(\tau) denote the coordinates of the curve c. In components the parallel transport condition is \frac{dx^\mu}{d\tau}\left(\partial_\mu X^\alpha +...

Would it be possible? -- A fifth mode of transport... There has been a lot of talk about developing a fifth mode of transport, and most of these involve some sort of tube such as the hyperloop idea from Elon Musk. Now I don't know why but I have the idea stuck in my head that the fifth mode of...

Hi, The transmission of nano devices are generally done without cosidering the spin polarization. However, as I saw in some papers, the effect of spin is sometimes included. How can I decide to use spin or not when simulationg transmission of nanoscale devices? Thanks in advance...

In GR, the geodesic equation for a test particle can be seen in 2 ways. (1) It is a fundamental postulate consistent with the EP that is experimentally verified. (2) It is derived from more fundamental postulates such as the Hilbert action with minimally coupled matter as an approximation...

One of these days on the TV I have seen news which has shaken me: Elon Musk has decided to intrigue the world - has declared that will soon open the project of essentially new personal transport. Which will move with speed of a sound, but will be cheaper than the plane . The construction cost...

Homework Statement Hi guys, I'm having trouble with a homework problem: I will have to solve for the IVP of a transport equation on R: the equations are: Ut-4Ux=t^2 for t>0, XER u=cosx for t=0, XER Homework Equations transport equation The Attempt at a Solution...

Hi guys, I'm having trouble with a homework problem: I will have to solve for the IVP of a transport equation on R: the equations are: Ut-4Ux=t^2 for t>0, XER u=cosx for t=0, XER I've actually never seen a transportation problem like this and any help would be...

I have a book on nuclear reactions which details the mean free paths for thermal neutron scattering as: 0.37cm for water and 2.2cm for heavy water The transport cross sections are listed as 0.45cm for water and 2.6cm for heavy water. Does anyone know how to calculate these from the thermal...

I have to calculate the transport coefficients for the Maxwell-Boltzmann distribution. But I'm not sure what distribution I have to use. As far as I know it should not be the MB distribution for v-space (Velocity) or E-axis (Energy), since that will get me the wrong dimensions in the end. I...

Discussion

Homework Statement I will honestly be so grateful if someone can explain this to me. I am studying the Reynolds transport theorem, particularly mass conservation. I have read over my notes and I really do not understand how to calculate the mass flow rate through the control surface if it...

You've heard of "Snakes on a Plane", right? How about roaches on a bus?

Homework Statement An engineer is designing a system that requires transporting .01 m^3/s of helium at 15°C and 120 kPa. The velocity of the pipe is limited to 40 m/s. What size (diameter) of pipe is needed? My question is what equation do i need to solve this problem? Homework...

In neurons during re-polarization ATP is used to "actively transport" Na ions out of the cell and K ions into the cell. Does this mean that the ions are flowing against their concentration gradient or the word "actively transported" is just used because ATP is used in this process?

Author: R. Byron Bird, Warren E. Stewart, Edwin N. Lightfoot Title: Transport Phenomena, Revised 2nd Edition [Hardcover] Amazon Link: https://www.amazon.com/dp/0470115394/?tag=pfamazon01-20 Prerequisities: Advanced Calculus, Differential Equations (ODE, PDE), Introductory Heat Transfer...

I am a graduate student in physics. Can someone recommend a book that explores transport phenomena or diffusion from a physical sciences (instead of engineering) point of view? I would like that because I'm not dealing with industrial equipment and don't want to spend chapters wading through...

Hi everyone, I'm trying to design a simple model by using Comsol Multiphysics. I set an inlet concentration of a species "cp" that will be adsorbed to a circular surface located at the center of the microfluidic cell (I named the concentration of adsorbed protein "cpl" ). I used laminar flow...

Torsion has propped up in a couple of recent threads, but none of my texts really cover it well. Does torsion make parallel transport direction dependent? I.e. if we parallel transport some vector v "forwards" along a curve, and then "backwards" along the very same curve to its starting...

Hello, everyone! I'm studying Nakahara's book, Geometry, Topology and Physics and now studying the connection theory. I come across a problem. Please look at the two attachments. In the attachment , Nakahara said we could use the similar method in the attachment to get \tilde X, but why...

Hi! My friends and I have been working on a project which encapsulates the use of semi porous transparent membranes that can selectively pass glucose molecules through them in one direction. Does such a membrane already exist? Where can I get literature on the construction and/or existence of...

Hello! I have two questions for knowledge. Q) Explain under what conditions Maxwell Boltzmann and Fermi Dirac statistics are applied on free electrons. Q) Explain each parameter of Boltzmann Transport's equation. Thank you in advance. :-)

I'm listening to Prof. Leonard Susskind's lectures on GR on youtube.com at http://www.youtube.com/watch?v=hbmf0bB38h0&feature=relmfu He's trying to explain how to visualize parallel transport of a vector. But I'm having a hard time of it. I think I understand it. Let me know if I got it...

I am a physicist trying to understand the notion of holonomy in principal bundles. I am reading about the horizontal lift of a curve in the base manifold of a principal bundle (or just fiber bundle) to the total space and would like to relate it to the "classic" parallel transport one comes...

I've heard that gravitational fields carry energy themselves, and are therefore a source for their own existence. I take this as a "pre-requisite" of a sort for gravitational waves. If I were to shoot a high energy laser in space and cause a rippling effect of space-time. Could somebody...

The future of the automotive industry and transport in the us? Why will Americans never fully take to rail? Because we are adventurers by nature. The people that came to this Country had adventure in their blood. We like our cars, and we like em big and fast. So then I tell you Rail is the...

So Reynold's transport theorem states that \frac{\mathrm d}{\mathrm d t} \int_{V(t)} f \; \mathrm d V = \int_{V(t)} \partial_t f \; \mathrm d V + \int_{V(t)} \nabla \cdot \left( f \mathbf v \right) \; \mathrm d V. Now I would expect (on basis of conceptual reasoning) that if I were to apply...

So from what I understand if you pass a vector (using parallel transport) through a closed curve where there is curvature in the interior, the vector will come back not to it's original vector but with a changed sense. However if the vector is on a geodesic it will not change its sense after it...

Homework Statement Please show that the defining equation for the parallel transport of a contravariant vector along a curve \dot{\lambda}^a+\Gamma^a_{bc}\lambda^b\dot{x}^c=0 is coordinate-independent, given that the transformation formula for the christoffel symbol being...

I am really not all that intelligent and fairly new to the whole mathematical equation solving thing. So please bare with me, I came to the conclusion instead of reading the daily paper I will read daily articles, as I am reading I am unfamiliar of course with the symbols being undefined in the...

Homework Statement Show that \frac{d}{dt}\int \rho r^{2}\phi dr = \int \rho r^{2}\frac{d\phi}{dr} dr Homework Equations Fundamental theorem of calculus The Attempt at a Solution So I follow the derivation from the textbook and I think I get the rather sneaky rearrangement of...

Assuming that we are working with an infinitessimally small region of a manifold so that we can consider only first order effects, does parallel transport in the absence of torsion necessarily "close the quadrilateral"? What I mean is, if I have two vectors (very small vectors) V and U, and I...

Hi All, I am an idiot but I don't understand the parallel transport: Parallel transport should be in surface right? [SIZE="3"][SIZE="5"]How to keep parallel and still be in surface?

Hello, First of all, please excuse me if I posted in the inappropriate place.. While a student few years ago, I used to work a lot with advanced differential geometry concepts, but never got an intuitive view of HOW humanity got to think about parallel transport, why it contained two words...

I am facing a problem on transport phenomena. Can anyone help me to solve this problem. I would really appreciate it. Its little urgent. I know that i have to use shell mass balance to start the problem but how to proceed further is what making me confused. In a beaker, a solid sphere of...

how do you use the change of variable: \xi = x - ct on the PDE ut + c ux = 0 where u(t,x) = v(t,x-ct) = v(t,\xi) to get vt = 0 I am trying to follow the steps of Peter J. Olver in this document http://www.math.umn.edu/~olver/pd_/lnw.pdf starting on pg 4 but get stuck here...i...

Hi, I've begun learning about General Relativity, though I've already had some exposure to differential geometry. In particular, I understand that Lie Differentiation is a more "primitive" process than Covariant Differentiation (in that the latter requires some sort of connection). My...

Hi all, Can anybody explain the Transport Theorem (http://en.wikipedia.org/wiki/Rotating_reference_frame#Relating_rotating_frames_to_stationary_frames) in more non-physicist terms? I simply can't wrap my head around the visual of this theorem, which has the gist of: d/dt f = df/dt +...

Can anyone explain to me reynolds transport theorem in the simplest way possible? for eg, under what circumstances is it used...etc

As an aero, I'm rather interested on what PFers would feel about flying on an UAV airliner... I'm kind of mixed; on one hand I would have no problems, but on the other hand I know some of the people who would be designing the control laws! I don't think the general public would want to fly...

Hello everyone! I have been on this website for quite a while, and found some interesting answers to many questions, and I decided to create an account to seek you help with a particular issue I encountered in my assignment. Please have a read, and thank you for any input! Homework...