Element Definition and 836 Threads

i was given that if y is an element in Hb then it is an element in Ha. that is Ha=Hb proof I said: since y in Hb then then y= h(1)b for h(1) in H to show that Ha=Hb let x be an elt in Ha hence x=h(2)a for some h(2) in H. now i am stuck

Hello, Some knows how to Bondi deduce his radiating line element? I read some papers and there isn't any hint about hit. Best regards

Hello, What is the most general cylindrically symmetric line element in the canonical form? Best regards.

Hi, I was just going over the moment of inertia for a 2D lamina, I've been happy with writing the small mass element dM as dM = ρdxdy where ρ is the area density, but for some reason decided on doing it like this, M(x,y) = ρxy so dM = \frac{∂M}{∂x}dx + \frac{∂M}{∂y}dy = ρ(ydx +...

So this is a review problem in our book I came across and i really want to understand it but I am just not having any luck, I did some research and found a guide on solving it but that's not really helping either. We didn't talk about unity elements in class and there aren't any examples in our...

Homework Statement The continuum element shown in Figure (a) deforms to figure (b) I'm looking to find the positions after deformation (x coordinates) by expressing them in terms of E coordinates. Homework Equations The Attempt at a Solution x1 = E1 + E2 x2 = E1 + E2 x3 = E3 The...

Hi everybody, I am interested to do some DEM(Discrete Element Method) simulation for my miniproject. So far I have seen that the most available opensource codes require large computation resource for parallel calculation. I don't have access to such facility and also my initial problem...

let say there is an bundle of fuel with 4 rings. Where ring 1 is center most ring and ring 4 is outer most ring. 1st ring contains: 1 fuel element 2nd ring contains : 6 fuel elements 3rd ring contains: 12 fuel element 4th ring contains : 18 fuel elements The general distribution of...

Suppose I write the following in my stylesheet .class1 { position: relative; } .class2 { position: absolute; bottom: 0px; } and then the following in my body <div class="class1 class2"> </div> Will that div take...

See image attached. (I've had a google but can't find anything). I am trying to understand the expression : Rdθ.2∏Rsinθ Here are my thoughts so far: Rdθ is the width of a strip, θ being the variable changing/to integrate over, giving arise to the elements. 2∏Rsinθ must then...

Here is the problem I have faced recently that I cannot deal with yet and I need some help: Given is the - list of elements (numbered): e.g. [1,2,3,4,6,7,8] - the count and size of groups, which can be used to cover the given set of numbers, e.g. groups with group size 2. - I need to find...

What are the advantages and disadvantages of both AEM and FEM and which on is easier. I am doing a project and I should use one of these two methods to solve for a truss system. P.S. computer programming shall be used. In the end which method is better for this case?

I found this matrix in the wiki: https://fr.wikipedia.org/wiki/Vitesse_ar%C3%A9olaire#.C3.89valuation_en_coordonn.C3.A9es_cart.C3.A9siennes I think that it is very interesting because it express d²A not trivially as dxdy. So, I'd like of know if exist a matrix formulation for volume...

A simple question about elasticity theory/finite element method: Suppose I have a tetragonal 2D piece of a linear isotropic elastic material, that has Young's modulus ##E## and Poisson's ratio ##\nu##. The vertices of the tetragon are at positions ##\textbf{x}_{1}##, ##\textbf{x}_{2}##...

What is a Standard State or Reference State of an element? Can someone please give me a simple explanation of what a standard state or reference state is? I don't quite understand the way wiki describes it which is - The standard state, also known as reference state, of an element is...

When we way that \frac{d^3p}{p_0}=\frac{d^3p}{\sqrt{m^2+\vec{p}^2}} is the invariant volume element, is that with respect to all Lorentz transformations or just proper orthochronous Lorentz transformations?

Hey! :o Given the following two-point problem: $$-y''(x)+(by)'(x)=f(x), \forall x \in [0,1]$$ $$y(0)=0, y'(1)=my(1)$$ where $ b \in C^1([0,1];R), f \in C([0,1];R)$ and $ m \in R$ a constant. Give a finite element method for the construction of the approximation of the solution $y$ of the...

I've been struggling with this for the past hours and I can't find a good answer. Using the integral for work W = \int_a^b \vec{F}\cdot d\vec{s} , when a > b , and the force is directed from a to b, i keep getting a negative result. I am considering d\vec{s} as the infinitesimal difference...

Hello All, Some of you may have heard of the freeware FEA program called FEMM written by David Meeker. It is used to simulate 2D electromagnetic geometries and also has an integrated LUA scripting host which allows script files to be written to automate the process. I'm currently using...

When doing surface integrals of surfaces described parametrically, we use the area element dA = ndS = (rv x rw)dvdw Where dS is the surface area element and v and w are the parameters. I'm fine with the derivation of this (I think) but I don't understand why it's necessary to have n and dS...

Homework Statement This is more about checking a solution I've been given is correct, because either my professor is consistently getting this wrong or I am.The Attempt at a Solution My professor's answers say [ \left( \begin{array}{ccc} 1 & 0 \\ 0 & 4 \end{array} \right), \left(...

I want to know what causes this specificity of reactions in between elements. Why does carbon only react with X elements? What are the factors that come into play to cause this specificity? From what I understand every element has the potential to bond with every other element but a lot of...

Hi, I have been stuck on a problem for a while now (3.24 part c). My attempt is as follows: Internal virtual work = external virtual work T/2 ∫0->L (∂u/dx)(∂v/dx)dx + ∫0->L (∂^2u/∂t^2)vdx = ∫0->L (Pv)dx Stationarity is already invoked on this functional as it's the principle of...

I developed finite element program (MFEM) in java for BVP &IVP to compute partial differential equation. I am facing one problem and description is as follows my problem is on generalized eigenvalue problem generated in wave propagation through rectangular wave guide in TE mode. (Differential...

Homework Statement The Question originally is to find the m of a solid uniformly charged solid sphere which is rotating uniformly with ω Now Homework Equations Now my question to you is how to take the small element? The Attempt at a Solution i take a small disc with...

Hello all, I have this matrix A \[A=\begin{pmatrix} 1 &2 &3 &4 \\ 9 &8 &2 &0 \\ 17 &2 &0 &0 \\ 1 &0 &0 &0 \end{pmatrix}\] B is defined as the inverse of A. I need to find the element in the first row and fourth column of B, without using determinants, so without using adjoint. How should I...

I write this in the hope that somebody reading this can explain to me, a laymen, in non-mathematical, plain English terms, why my thinking is wrong regarding the calculation of the age of the observable Universe and the formation of the elements in the Periodic Table given the (short) age of...

I found the equation for the speed of an electron today. atomic number*fine-structure constant*speed of light. rearranging we get z= v/σc. if you set v to c then you find that at element 137 the electrons become superluminal. This can be possible right? a retrocausal atom! Could someone please...

I am thinking about taking a finite element method course. I know what FEM is and how it solves boundary value problems and stuff but I'm wondering how widespread it is used... Is it a useful numerical technique? What industries/research use it? I am interested in research in continuum...

Question 2 (a) how is it possible? B is a set (since A is a set), how can a set be an element of another set? Rather than saying: B is an element of C I thought it would be better to say: B is a subset of C. Also, can someone explain question 2 (d) to me? thanks

I want to compute the flux surfaces using FEM but i haven't found any good source to read. any help will be appreciated. Thank you

hi Guys, i Needed your help to prove out the following, thanks in advance; Let u1,u2,...,ut be vectors in $\Re^n$ and $k\in\Re ,k\neq0.$ Prove that $Span\{u_1,u_2,...,u_t\}=Span\{ku_1,u_2,...,u_t\}$

A piece of unidentified element X reacts with oxygen to form an ionic compound with the chemical formula X2O3. Which of the following elements is the most likely identity of X? A) Ba B) Cs C) In D) P E) Zn I am doing exam practice questions...

I have a problem asking to prove the following statement is false: "Every non-empty set of integers has a least element". This seems pretty intuitively false, and so I tried to sum that up in the following way: Suppose we have a subset \(A\) in the "universe" \(X\). Let \(A=\{-n: n\in{N}\}\), a...

Field Theory - Element u transcendental over F In Section 10.2 Algebraic Extensions in Papantonopoulou: Algebra - Pure and Applied, Proposition 10.2.2 on page 309 (see attachment) reads as follows...

Hey guys! Basically, I was wondering how to prove the following statement. I've seen it in the Hamermesh textbook without proof, so I wanted to know how you go about doing it. Let's say you have a group element g_{1}, which has a corresponding inverse g_{1}^{-1}. Let's also define a linear...

I highlighted a portion in the paint document. Is that a mistake? How am I supposed to compare the polarity of the wire connected to the left to the polarity of the wire connected to the right?

Or some naturally occurring material what would I use. I'd like the strongest constant uniform magnetic field possible. Is there some sheet of material I can use?

Homework Statement I need to prove that Q[√2,√3] = \{a+b√2+c√3+d√6: a, b, c, d \in Q\} is a field. Homework Equations The Attempt at a Solution I proved all axioms except the existence of inverses for nonzero elements. My problem is that multiplication is quite hairy. I ended up...

Homework Statement Show that in cylindrical coordinates x = \rho cos \theta y = \rho sin \theta z = z the length element ds is given by ds^{2} = dx^{2} + dy^{2} + dz^{2} = d \rho^{2} + \rho^{2} d \theta ^{2} + dz^{2} Homework Equations -- The Attempt at a Solution...

1. I need to find the element being oxidized and reduced for: CO2 + C = 2CO I don't know how to do it for this one. 3. I know how to do it for ones like this: 2Al + 3Cl2 = 2Al(3+) 6Cl(-) it would be zero for elemental Al and Cl and the oxidation number for the...

Dear All, I just have a single element, I need to apply a plane stress condition as in the attached image. For the boundary conditions; • I have constrained the nodes 1 and 2 in the horizontal (x) direction • I have constrained the nodes 1 and 3 in the vertical (Y) direction • I have...

I'm building (or rather, debugging) a lightning detector that detects the electromagnetic charge emitted by a lightning bolt. I need a good way to generate a little lightning as a test signal and I'm currently using a the piezo electric part of an electric lighter which generates a small...

the two energy level atom, whose hamiltonian takes the form \hat{H_A}=E_g|g\rangle\langle g|+E_e|e\rangle\langle e|, where E_g as well as E_e represent the eigenvalues and |g\rangle as well as |e\rangle denote the ground state and excited state. There is an interaction between the atom...

Is there a term for the least k such that a^k = 1 in some ring R (if it exists, specifically in a finite ring)? Is there a way to get an upper bound in general? I know that it's hard to get even in say F_p, but I'm just looking for some conditions that would help me understand what it looks like.

Hello, I’m a sci-fi writer and I wish to gage the believability of (or lack of) the following which I’m using in a story. Concerning the extensions to cosmology and quantum physics, one of the cornerstones of my book’s sci-fi universe stems from a strange and intriguing fact that I’ve...

Hi, This is a sample problem from logan finite element method. I have attached the problem and solution given in the book. As per the problem i first derived the stiffness matrix and den putting the boundary conditions started solving for the forces. I am stuck as three forces are unknown but...

Hello! I ve come across with something called ' relative element of a vector' Could you provide me a definition and how is it used? Thank you

Dear all, Please tell me the steps are used to find Modal loss factor of composite constrained layer damped beam by using Finite Element software such as ANSYS etc.