Element Definition and 836 Threads

Hi, I have to write a spacetime line element for the shape of a cube of cosmological dimensions. This cube is expanding like this: i)With time, the cube becomes elongated along the z-axis, and the square x-y shape doesn't change. ii)The line element must be spatially homogeneus. (I don't...

As I know, the method to solve neutron problem is divided into two steps now, neutron transport calculation for fuel assemblies and neutron diffusion calculation for whole reactor core, both using specified code such as CASMO and SIMULATE from STUSVIK. I want to know whether the commercial...

My two questions are related to the title. The problematic is: "How can we connect the coordinates ... xα... for α = 0, 1, 2 and 3 to the coordinates of the same object in another frame, say ...yλ for λ = 0, 1, 2, 3 in preserving the quantity η(x)αβ. dxα.dxβ = η(y)λμ. dyλ. dyμ? Can someone...

Homework Statement The current flowing through an element is i = 2 A for 0<t<1 and i = 2t^2 A for t>1 Calculate the charge entering the element from t=0s to t=2s. Answer: 6.667 C. Homework Equations I used Q=t1∫t2 i dt The Attempt at a Solution I tried to solve using...

Homework Statement A circuit is constructed with two capacitors and an inductor as shown. The values for the capacitors are: C1 = 513.0 μF and C2 = 68.0 μF. The inductance is L = 265.0 mH. At time t =0, the current through the inductor has its maximum value IL(0) = 106.0 mA and it has the...

Here's what I know: Scientists used mass spectrometry to figure out the number of electrons in a neutral atom of the element. We know that if an atom has a neutral charge, the number of protons = the number of electrons - therefore, the atomic number = the number of electrons. Would anyone...

I'm currently studying the pion leptonic decay and I'm getting a bit confused about some factors. Firstly, le correct lagrangian that describe the pion decay \pi^+\rightarrow l^+ + \nu_l is: $$L=\frac{4G_F}{\sqrt{2}}V_{ud}^* \bar{d}_L\gamma^\mu u_L \bar{\nu}_L \gamma_\mu l_L$$ We can't...

assuming that the system (s,*) has an identity element. if the equation (a*b)*(c*d)=(a*c)*(b*d) holds for all a,b,c,d belongs to S , ,prove that:* is associative and commutative . I tried so much but with no good result ! any ideas ?

Let $S=\{ 1, 2, \ldots , 2p\}$, where $p$ is an odd prime. Find the number of $p$-element subsets of $S$ the sum of whose elements is divisible by $p$.Attempt. Let $\mathcal{K}$ be the set of all the $p$ element subsets of $S$. Let $\sigma(K)$ denote the sum of the elements of a member $K$ of...

TA sample of 24Na has a half-life of 234 hours, How much time elapses before a 5μg sample contains 1μg of undecayed atoms? I have calculate the decay constant (8.23x10-7) What do I do now?

Homework Statement Transform the line element of special relativity from the usual (t, x, y, z) coordinates rectangular coordinates to new coordinates (t', x', y', z') related by t =\left (\frac{c}{g} + \frac{x'}{c} \right )sinh\left (\frac{gt'}{c} \right) x =\left (\frac{c}{g} +...

I'm making a circuit to control the temperature of a peltier element, and I'm trying to figure out the cheapest way that will actually work over the long term, and not burn out my components fast. At first I wanted to just use standard power regulation to control the power to the element and...

Hi All, I'd like to what kind of steps need to be taken to accurately estimate the yield lines of RC structures. My intention is, to know what type of loading is acting on beams transferred from slabs. I know how to formulate thin/thick plates and shells. The results converges with commercial...

Hi I would like to know is there any way except using graph to find area element in cylindrical ( or Spherical) coordinate system? Thanks.

Folks, I have the book An Introduction to the Finite Element Method by J.N Reddy. The following website provides http://highered.mcgraw-hill.com/sites/0072466855/student_view0/executables.html access to the Fortran Executable but I am not sure how to work them. I am just beginning to...

The question is, "determine whether 2 is a set of the following," the set being {x∈R|x is the square of an integer} I think I might need a bit of help interpreting the meaning; I believe its saying that if you square some number, you'll get x, right? I just need a little help reading this.

Homework Statement Let A, B, and C be sets. Assume the standard ZFC axioms. Please see below for my updated question. Thanks.

I've been given the following problem (attached), not sure how to tackle this one, do I use mesh/node analysis and super node analysis, or can I find the v in the loop with the dependant voltage source then use that as the supply to the second and third loops? Not sure, any help would be...

Folks, Is there anyone out there familiar with 'An introduction to the Finite Element Method' by J.N. Reddy? I am struggling to decipher what is happening on page 129 as shown in the attachment. If some-one is willing to help I will reply with a more specific query on that page. Thanks

Dear All I want to know the formula to extract the longitude of the satellite from the TLE below. I hope someone can help. Thanks 1 24652U 96063A 97251.85429118 .00000144 00000-0 00000-0 0 568 2 24652 0.0850 104.0202 0008355 303.2059 279.6585 1.00288964 3492

Homework Statement Suppose a nameless element (X) was found to occur in three different substances (A, B and C). The relative molecular masses of A, B, and C were found to be 25.80, 43.70 and 83.50 respectively, compared to an assigned value of exactly 2.00 for H2. Subsequently, these...

Homework Statement Say we have a function such that x = uv , y = (u^2 - v^2) /2 Hence our line element in Cartesian coordinates is. ds^2 = dx^2 + dy^2 Now I have two questions. I like to work on math problems algebraically if possible so I thought to convert our line element I could take...

Homework Statement If G is a group, a is in G, and a*b=b for some b in G (* is a certain operation), prove that a is the identity element of G Homework Equations The Attempt at a Solution I feel like you should assume a is not the identity element and eventually show that a= the...

I am slightly confused with the invariance of four-volume element. The orthodox way to show it is to prove that Jacobian is one, that I did, however in many textbooks I find a reasoning that because we have Lorentz contraction on one hand and time dilation on the other hand, the product is...

1. Determine the power supplied by the leftmost element in the circuit Homework Equations Power = Voltage ( Current) The Attempt at a Solution As power = voltage (current), that is the equation that will be used. The leftmost element shows a current of 2 AMPS entering through...

Hello, I know the value of a field variable in a 3d mapped finite element mesh. Can anyone suggest an effective method/methods to find its gradient throughout the mesh.

In a simple circuit having battery (6v) connected to two resistors (1K each) in series, 3mA would flow through the entire circuit. 1) If resistor is a current limiting element, current following the first resistor should reduce its value (from 3mA to some other) before entering the another...

I was thinking about identities, and seem to have arrived at a contradiction. I'm sure I'm missing something. A(n) (two-sided) identity for a binary operation must be unique. I will reproduce the familiar proof: Proof: Suppose a is an arbitrary element of a set S, e and e' are both...

Hello, currently I work on 2->3 scattering process. So there exist five external momenta and in my case 5 different Feynman diagrams, for which I have already calculated the full matrix element. The matrix element is a function of various scalar products of the four-momenta. This scattering...

Hi all, Papapetrou line element describes an axial symmetric stationary spacetimes and the coordinates that appear in this metric are just similar to cylindrical coordinates; I mean they are labeled ρ, z and phi. I want to know if they are really the cylindrical coordinate or not; In other...

Homework Statement The oxides of a certain element contain 27.28%, 42.86% and 52.94% oxygen. What is the ratio of valencies of the element in the 3 oxides? Homework Equations The Attempt at a Solution Following calculations were made: Molecular mass of the first oxide is 58.6...

Hi, i need some help in writing the surface mesh in abaqus. i have a wing model, meshed using hexahedral mesh. now what i want is to write the surface element detail on a file, containing the element number and its neighbouring four nodes. for example 12, 2 3 5 6 here 12 is the element number...

I have a polymer sample and am interested in qualitatively determining the sulfur (sulfate group) content. Which analytical technique should I consider using? This polymer is not soluble in water but is soluble in THF and toluene. Thanks.

Hi, I'm facing a real-life problem and I don't what specific mathematics topic it's related to. Homework Statement I know the value of the components of a vector field in three points of space and I have to find the flux of this vector field through the surface defined by those...

while working with ansys classic, while adding link element 2D spar is not available in the list,do i need to install it additionally? if yes how? or otherwise what can i do?

Homework Statement The area element of a sphere in spherical coordinates is given as following dA = r^2 \sin(\phi)\; d \theta \; d \phi using the notation in the following figure: However, while going through some E&M books I ran into the following notation Surface \; Area = r^2 \...

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...

\inthi all, I need just little bit of confirmation about what I'm doing. Normally I know how the stiffness matrix is composed for 2 node frame element in 3D space. which creates 12x12 matrix for that element, if there is also thermal loading on frame element additional...

In one of the early chapters of Gravity by Hartle, he is developing the line element on a sphere in preparation for developing the concept of a spacetime interval. Whilst finishing up the proof Hartle sort of implicitly says that if two lines are orthogonal the line element connecting two points...

Hi, If I have a vector c = [ a , 1 ]T where the element a is a vector. If I multiply c by its transpose: cTc is this defined? How do I calculate the a*a? Matrix multiplication rules would say that a * a is undefined because it is a nx1 matrix multiplied by a nx1 matrix. Or is the...

Hi all. I would like to do a finite element simulation of a coil in a time-varying magnetic field, to see how much current is induced in the coil, and also to see how the coil itself affects its surroundings. Now my question is, how do I model a coil with several thousand turns in a practical...

if I have square matrix A whose decimal elements a_{i,j} = \frac{v_i}{v_j} how do I find (or approximate) the vector that would produce the matrix elements. what's a good way to do that? i guess you can scale the vector however you want and it'll still produce the same matrix.. thanks.

I need to design a voltage doubler that takes in 115V-50Hz a.c. and produces a doubled voltage output of 230V dc. I am using this circuit: I need help in the mathematics part: i) How do I find the optimum value of capacitance? (Using high capacitance values reduces ripples; but can...

Hi all. In most of our analysis of continuous systems ex: in fluid mechanics, solid mechanics etc. we consider a differential element(infinitesimally small element) and obtain the differential equations that govern the phenomenon. But why do we consider a differential element? What is it's...

I am in trouble… I am a master student (first year) in theoretical particle physics and I have been working for several months on the calculation of the total cross-section at leading order for the process: u + \overline{d} \rightarrow W^{+} + \gamma I performed the whole calculation by...

Hi, I'll cut to the chase: I've been designing a project that uses a series of MCUs and such, in order to control a series of systems. The device is ment to run from a standard 120 V wall outlet, has a few motor controls, a piston control, but problematically also needs a heating element that...

Homework Statement Let a and b be elements of a group,with a^2=e , b^6=e and a.b=b^4.a find its order and express its inverse in form of a^m.b^n Homework Equations The Attempt at a Solution (ab)^2=(ab)(ab)=(ab)(b^4.a)=a(b^5)a (ab)^3=a(b^5)a(ab)=a(b^5)(a^2)b=a(b^6)=ae=a it...

http://news.yahoo.com/livermorium-flerovium-join-periodic-table-names-213303266.html http://phys.org/news/2012-05-livermorium-flerovium-periodic-table-elements.html http://www.webelements.com/flerovium/, Fl http://www.webelements.com/livermorium/, Lv

Structural Analysis-Writing Finite Element Code, Dear all, I have written a code ( in fact it is a software) for 3D finite element structural analysis. While developing the code I found that assembling global stiffness matrix is quite complicated. The complication is even more when we...

Hi All, I have this clarification, if I have a resistor element of any value and if the physical length of the resistor is say L. Does the resistance of the element increases from 0 at the beginning to R at the end of the resistive element that is L, or it is the average, or it is located at...