Transport Definition and 239 Threads

Homework Statement In the book, Nuclear Reactor Theory, Glasstone, Bell, under section 2.2 SOLUTION OF THE ONE-SPEED TRANSPORT EQUATION BY THE SEPARATION OF VARIABLES, I have difficulty in understanding the derivation. Hope some one can explain the derivation or give a reference where the...

Since for a general contravariant vector, ##\nabla_{\nu}V^{\mu}## will not in general be zero, is it correct to say that all of them are transported by Fermi Transport? (With the only vector being parallel transported being the four velocity vector?)

I'm currently in a GR class and have come across the notion of parallel transport, and I've searched and searched the last few days to try and understand it but I just can't seem to wrap my head around it, so I'm hoping someone here can clarify for me. The way I picture parallel transport is...

I've managed to derive the form of Reynolds transport theorem as a bilance of linear momentum of the system: \left (\frac{\vec{\mathrm{d} p}}{\mathrm{d} \tau} \right )_{system}=\frac{\mathrm{d} }{\mathrm{d} x}(\int_{V}^{ }\vec{v}\cdot \rho dV)+\int_{A}^{ }\vec{a}dm+\int_{A}^{ }\vec{v}\cdot \rho...

I cannot understand the the relation between Reynolds Transport Theorem and Volume Calculation. Volume calculation is an simple, straightforward process which, I think, have much connection between Reynolds Transport Theorem. We calculate volumes in thermodynamics, heat transfer and fluid...

The recent thread on parallel transport has raised a couple of things I'd like to review for my own sake. I'll address them one at a time as my time permits. The first question is this. If we offer ##t^a \nabla_a u^b## or the equivalent ##\nabla_{\vec{t}} u^b## as the definition of parallel...

Good Day Guys, I need help in checking the beam size required to transport a cargo. What checks do i do? 1. Check actual BM with resisting moment of the beam 2. Check actual shear with the resisting moment of the beam How do i calculate following if I only know the type of beam used, i.e...

Background: I am taking an undergraduate fluid mechanics class. I seem to have a misunderstanding with my interpretation of Reynolds Transport theorem (RTT), which I have written below: $$\frac{DB_{sys}}{Dt} = \frac{\partial}{\partial t}\int_{CV}\rho bd V +\int_{CS}\rho b \vec{V}\cdot...

Hello everyone ! I wanted to ask you if anyone ever encountered problems with proton transport using MCNP. In particular, the production of electrons when protons interact with matter. I have been trying to figure it out modifying the different physics cards (phys, lca, ...) with no result...

Hey guys, I got this problem: We had the derivation of the ekman transport today in class. And what I wondered about is this: Usually the equation for the ekman transport looks similar to this (depends on the author) u = V_0 e^{az} cos(\frac{\pi}{4}+az) v = V_0 e^{az} sin(\frac{\pi}{4}+az)...

Hello, I have 2 questions regarding similar issues : 1*) Why does one say that parallel transport preserves the value of dot product (scalar product) between the transported vector and the tangent vector ? Is it due to the fact that angle between the tangent vector and transported vector is...

Hello! I try to think about the Foucault pendulum with the concept of parallel transport(if we think of Earth as being a perfect sphere) but I can't quite figure out what the vector that gets parallel transported represents(for example, is it the normal to the plane of oscillation vector?). In...

I learned about Tesla's valve and how, without moving parts, it wouldn't be useful enough. But my question is, can I make a pipe with the valve's structure, and only apply heat in order to create flow. I know things follow the path of least resistance, and with a constant addition of heat, I'm...

Hello, I'm studing the history of this phenomenon. Does someone has the original paper of A.G. Walker of 1932?

Hi there, I am always confusing in the difference between diffusive and ballistic transport. My understanding on the diffusive transport is from it's name, particles diffuse from the high density region into the low density region. I think the diffusion happens towards all direction, is it why...

I'd like to purchase one of these books for self-study. The BSLK Introductory Transport Phenomena claims: "Devoting more space to mathematical derivations and providing fuller explanations of mathematical developments—including a section of the appendix devoted to mathematical topics—allows...

I know Mars colonization is a hot topic these days, and there are a lot of threads on this topic, but I would like to discuss specifically the SpaceX Interplanetary Transport System. There's a video on the subject here. On a recent thread that I posted here, some people came to the conclusion...

Elon Musk presented SpaceX's plans for its manned missions beyond Earth orbit yesterday. SpaceX is well known for missing their deadlines (like most in the space industry, to be fair), so we'll see how long it will take to develop it. The question how it will look like is clearer already, here...

Hello, When looking at the simplest definition of mechanical devices, is there a way to transport something non-mechanically? Physics isn't my strong suit, but it seems to me that all transport is mechanical in nature. The phrase 'mechanical transport' comes up a lot in political discussions...

I have to say first that I found quite a similar question under https://www.physicsforums.com/threads/poynting-vector-dilemma.331375/ However those thread ended without real answer.There shall be the following simple setup: A battery, and quite at a distance a light bulb. They are connected by...

i am a physicist now i am doing Ms in nuclear engineering ... i need to understand basic concepts ... neutron transport equation ? what is the transport phenomenon actually ? and pressure drop calculations in core ... please help thanks in advance

hi, first of all in this image there is a fact that we have parallel transported vector, and covariant derivative is zero along the "pr"path as you can see at the top of the image. I consider that p, and r is a point and in the GREEN box we try to make a taylor expansion of the contravariant...

Homework Statement Explain why large transport trucks have a hard steel barrier between the load and the driver's cab. Consider Newton's first law in your answer. Homework Equations no equations required.The Attempt at a Solution According to Newton’s first law, if no net force acts on an...

Homework Statement Homework Equations one dimensional Reynold's transport theorem The Attempt at a Solution [/B] I started with this equation, and tried to expand it using the equation given in #2. This is the farthest I have gotten so far. I got stuck from here. I do not know how to...

I'm in a logical loop here: 1. A tensor undergoes parallel transport if, as it moves through a manifold, its covariant derivative is zero. 2. Covariant derivative describes how a tensor changes as it moves through a manifold. 3. A tensor undergoes change as it moves if it does not parallel...

Hi, Could someone explain to me how exactly ATP changes the shape of a transport protein? If ATP, when hydrolyzed, releases free energy, how does this energy change the conformation of the structure of the protein? Additionally, why must a phosphate group attach itself to it? Thanks!

So I have NO IDEA how to do this problem. I am assuming it has to do with linear transport because that's the next section in the book but we have yet to talk about this in lab and briefly (one slide) discussed this in lecture. I tried reading in my book which was did no good as it just showed...

Hello! In my course on physical transport processes time and again these type of equations, containing partial derivatives, appear: But how do you actually calculate such an equation? I know how to take the partial derivative from a function like x²tz³. Would it be that I am given a...

Hello there! I'm new on the forum and english is not my first language. I'm working on an art project and I wonder if there's any mean by which I can transport the light from an illuminated scene across a small tube (let say not larger than 5 cm in diameter) and over some distance (let say 2...

In superluminal light pulse experiments, as shown in Fig. 4 of the Letter [Nature 406 (2000) 277], the whole pulse intensity profile observed is advanced by 62 ns nearly without any distortions, and the light pulse energy must be transported faster than the speed of light in vacuum...

I cannot find a website that answers this question, and all diagrams I see do not show that ATP is used. Does this mean that these processes are intrinsically spontaneous? I can see how the electron transport chain is spontaneous, as the oxidation of oxygen to water is favorable (E 1/2=0.7V).

Homework Statement A charge Q = -820 nC is uniformly distributed on a ring of 2.4 m radius. A point charge q = +530 nC is fixed at the center of the ring. Points A and B are located on the axis of the ring, as shown in the figure. What is the minimum work that an external force must do to...

hello all, I just wanted to check my worded interpretation of this otherwise messy result is ok:

Does plasma transport oxygen?

Hello, I've just read and I think I have understood the following result : If we were to geodesically transport all points of a small 2D surface, so small that it would be flat for all purposes, in a direction vertically above it, and if this surface belongs in an arbitrary 3D manifold, then in...

Greetings PFers, Would it be possible to move microscopic particles of a wide range of composition (conductivity, density, etc...) using a directed beam technology? The idea is to have a fast 3D printing technology (practically no moving parts) that is capable of depositing of a wide array of...

Hello! (Wave) Definition A partial differential equation is called dispersion equation if it allows solutions in the form of a wave function and furthermore solutions in the form of a wave function with different wavenumbers have different velocities. The relation between the cyclic frequency...

Greetings, PF! I have some questions regarding the problem I attached below. It is some sort of Couette flow variation. It's not homework, I'm just learning the basics of TP on my own. I fully solved the problem with the Navier-Stokes and continuity equations, using some assumptions in order to...

So I've found several instances in which Bernoulli and Conservation of momentum (in Reynolds transport theorem form) give different answers for the study of an inviscid fluid. Let's consider a simple situation as described in my diagram attached. Basically a tap/faucet is releasing fluid, which...

I would like to reproduce results from a much older code to test a new one. I only have the old code's results in the form of plots, not data, but I need data. The older code solves the unsteady vorticity transport equation in 2D with a constant kinematic viscosity term. I'm interested in 2-D...

I'm currently teaching a gen ed course called Relativity for Poets. This is the first semester I've taught it, and it's been a ton of fun so far. If anyone is curious, http://www.lightandmatter.com/area3phys120.html is the class's web page with links to the syllabus and lecture notes. The...

I have been reading section 3.1 of Wald's GR book in which he introduces the notion of a covariant derivative. As I understand, this is introduced as the (partial) derivative operators \partial_{a} are dependent on the coordinate system one chooses and thus not naturally associated with the...

Show by direct calculation that Eqs. (4-134) and (4-137) in the textbook by Duderstadt and Hamilton hold, i.e.:(a) ∫ dΩΩiΩj= 4π/3 δij; i,j = x,y,z; 4π(b) ∫ dΩΩxΩyΩz = 0, if l, m, or n is odd. 4π The integrals are over 4π. This is part of the derivation of the diffusion equation...

I am studying parallel transport in order to understand Berry curvature, but I know this topic is most commonly used in GR so I'm posting my question here. I do not know differential geometry. I am looking for a general explanation of what it means to parallel transport a vector. Mostly I am...

Clock transport can be used to compare one clock with another in an absolute sense. All we have to do is to transport a clock between two A-frame clocks that have been synchronized per Einstein's definition. Let's call the transported clock "T" and the left-hand and right-hand E-synch'd clocks...

1. Homework Statement Calculate the torque on the dam about the origin (Picture attached) due to the pressure force of the fluid. Homework Equations Pressure force is correct (dF) The Attempt at a Solution [/B] I have solve it; however, I am not sure if I calculated over the origin asked...

In several fiber-optic-based probes in medical imaging fields, the light travels towards an object through an optical fiber (or even free space), interacts with the object and then travels back through the same fiber (or the same path in free space) and is captured by a camera or photodetector...

Hi guys, I want to calculate an explicit example of a vector parallel transported along a cardioid to see what happens. Maybe someone could help me with that since no author of any book or pdf on the topic is capable of showing a single numerical example. So we need a vector field on a manifold...

In my recent studies of curvature, I worked with the Riemann tensor and the equation: (\deltaV)a= A\muB\nuRab\mu\nuVb Now previously, I worked in 2D with the 2 sphere. While doing so, I learned that if I set my x1 coordinate to be θ and my x2 coordinate to be ø, then the vectors that serve...

I recently derived the Riemann tensor (Rabmv) for the 2 sphere. I then did RabmvUbVmWv to calculate dva (the change in the vector va as you parallel transport it around the loop of the sphere). The result I got for dv1 was 0. I got 0 for dv2 as well. I am just making this thread to...