# Tagged Questions

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2k views

### Effective refractive index calculation of fiber core

Can someone pls explain what is effective refractive index of fiber core and how to calculate it theoretically? Suppose the fiber core refractive index=1.4446 and cladding refractive index is= 1.4271, ...
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### Mass scaling in molecular dynamics

I've noticed some authors scale the mass of particles in molecular dynamics simulations while leaving the force field parameters the same in order to achieve materials of different densities. Does ...
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### Analyse astronomical data

Recently I was told of a job offer to analyse astronomical data. The job offer states that they want somebody with knowledge of astronomical data analysis software and it will be a plus somebody who ...
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### Final-state baryons in $p \bar p$ collisions in Pythia

I'm trying to simulate inclusive $\chi_c$ production in $p \bar p$ collisions at very low energies (~ 5.5 GeV) using Pythia8 event generator. Leaving aside problems bounded with applicability of ...
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### How to calculate dispersion relation from a Finite Difference (FD) wave simulation

I have a python code that calculates the solution of the inhomogeneous acoustic wave equation for a 2D medium with any velocity and source configuration. It was implemented using Finite Differences ...
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### Maximum-Entropy Method deconvolution implementation?

I am looking for an implementation of the Maximum Entropy Method for image deconvolution, ideally in MATLAB or Mathematica. I'm trying to reconstruct an image from fringe visibilities, as is often ...
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### Comparison of different ab-initio codes

One may find on the web a lot of different computational packages to perform "ab-initio" calculations of electron structure of the solids. Usually, the documentation is not quite transparent about the ...
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### How can one activate the decay of the quark b with PYTHIA event generator?

This is my problem and I hope finding a solution. _In the simplest alternative, MSTJ(22) = 2, the comparison is based on the average lifetime, or rather (c*tau "time life") , measured in mm. Thus ...
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### How to let Pythia to output the complete event record in LHEF or StDHep format?

I am currently using Pythia 6.4 to simulate some processes (I do not have the intention to upgrade to 8). Now, I need Pythia to output its event record in the format of LHEF or StDHeP. I accidently ...
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### 3D Simulation Software

I need a software capable of simulating the physics of a car going off a ramp. This is a stunt that I will be attempting and looks like the following: A car, going off a curved ramp, doing a barrel ...
622 views

### Sum of energy in a free rotation with Algodoo software

I try to understand why Algodoo software (freeware) give an efficiency greater than unity. I tested several scenes and at each time I can look the software give energy, I don't say it's all the time ...
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### Gerstner Wave Formula to Vertex information $(x,y,z)$

I have created a program, that draws a plane mesh, and allows to me edit or animate all the separate vertices along it. The idea behind it, is for me to be able to create a gridMesh based wave ...
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### What software do publishing companies use to create drawings for text books?

What software is used to create free body diagrams, inclines, springs and so on in the introductory physics textbooks ? I know Adobe, Luxology, and many others could, but I am more interested in ...
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### Toolbox for Complex Networks and Graphs

Is there a toolbox which helps in visual simulation and modeling of a network (say a mesh or ring) consisting of coupled synchronized system of nonlinear equations(ODE) which represent a system of ...
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### Algorithmic approach for applying Kirchhoff's Rules to circuit analysis

Working with Kirchhoff's rules, I am attempting to device an algorithmic approach to finding the unknowns of the problems, I am of a Computer Science background and I am finding it difficult to ...
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### What is wrong with my formulas for a mathematical model of a double pendulum?

I tried mathematics but I've had no response in a month. I wanted to create a computer simulation on Matlab, using a model for a pendulum from this study (A double pendulum model of tennis strokes. ...
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### Mathematica code for self-consistent field loop in Hartree-Fock method

I want to write a Mathematica code for Hartree-Fock treatment of helium (or hydrogen molecule-> namely two electrons systems) , but I don't know how to write a loop for self consistent field procedure....
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### C libraries for Solid State Physics

During last year I've attended courses of solid state physics, and I studied methods for bands structure calculations in the Hartree Fock framework. However, I know only theoretical aspects of these ...
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### Physical pendulum dynamics confusion

I'm validating a Matlab Simulink SimMechanics model analytically. The model consists of a physical pendulum (uniform rod with length $l$ and width $w$) which is torque driven. I'm somewhat confused ...
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### use FEMM to simulate electric field for a magnet inside a coil

I'm trying to simulate a magnet inside of a coil of wire, with and without current running through the wire. I'm using the free FEMM software to try to simulate this, but I don't think i'm setting ...
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### Any freeware or shareware (demo/evaluation version) software to peak match XRD precalculated pattern?

I have an XRD data with an already calculated pattern from another analysis software and I need to peak match this pattern to XRD database. Is there freeware or shareware to do it. I tried crystal ...
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### Finding the distance a spaceship would travel given a time of departure and velocity

Let's say a spaceship leaves Earth at a day t and with velocity v. Is there a way to know how many kilometers it will cover to arrive on Mars? This would be a trivial question were it not by the fact ...
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### Electromagnetic scattering $T$-matrix in MATLAB

My problem with the inverse of the matrix T (in the photo) , the matrix consists of Bessel and Henkel functions in high order (the orders from 1 to 21), then the elements of this matrix arrived to ...
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### Simulation software for wave optics

I am using COMSOL multiphysics Optics module for wave optics simulations and I am wondering if there is better simulation software for wave optics simulations (no multiphysics needed). Like software ...
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### RF cavity Field Maps using Poisson Superfish

This may be a slightly obscure question but I'm trying to use Poisson Superfish to generate field maps for single cell of an ILC SRF Cavity. There are examples in the documentation for radio ...
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### Software for BEC dynamics in optical lattice

I am looking for a quantum chemistry software that deals with Bose-Einstein condensate in optical lattices (1D, 2D, 3D). I am interested in full many-body Schrodinger equation (two-body interactions - ...
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### Setting up initial configuration of a Micelle - Molecular Dynamics

I have just started learning Molecular Dynamics using dl_poly_classic and analysing trajectory using nMOLDYN. Our primary aim is to do neutron scattering, but however we do Molecular Dynamics to ...
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### Accelerometer Pitch and Roll Calculation

I am developing an application for a device that needs to know its tilt/orientation, specifically, pitch and roll. Roll is positive if the right side of the device is elevated, and pitch is positive ...
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### What is the electron barrier tunneling mass, and why it is necessary? What is the ebarrier tunneling mass of AlGaAs?

I am doing solar cell simulations in synopsys software. I am getting a persistent error saying ebarrier tunneling mass has not been defined. Is anyone familiar with this error? What is this ...
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### Initial conditions for second order ODE with complex stiffness

I tried this on Math Stack Exchange. I'm trying to find initial conditions to ensure systems of the form stay bounded $$\ddot{x}_i+\sum_{j=1}^N k_{ij} x_j = 0, \quad k_{ij} \in \mathbb{C}.$$ For ...
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### How to properly implement Huygen's integral?

I'm really confused by what's happening ... I'm trying to propagate a beam some distance and compare initial and final intensities. Lets say the initial electric field is just cos(200x). I then used ...
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### Projectile motion with wind

I am trying to simulate a projectile motion with wind and gravity. (I'm a programmer so excuse my knowledge on the subject) I want to know launch rotation of a person in 3d to throw a ball forward ...
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### Are there datasets with light spectrum samples and their respective 1931 CIE XYZ values?

I'm developing a software (.NET/Mono) library to work with color spaces and light spectrums, and I want to add many test cases in order to ensure software quality. I've programmed code to convert ...
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### Coupled Oscillation Simulation

I'm looking for an online coupled oscillation simulation. The best I have got so far is this --- https://phet.colorado.edu/sims/normal-modes/normal-modes_en.html But I'm looking for something which ...