Model Definition and 1000 Threads

According to physicist John Wheeler, the universe is part of a sequence of cycles of Big Bangs and Big Crunches, called cyclic or oscillatory universe model (https://en.m.wikipedia.org/wiki/Multiverse (Mentioned in "Classification schemes") According to this author, in each cycle, the laws of...

I greatly appreciate this opportunity to submit a query, and apologise for posting two simultaneous, but unrelated, queries on the forum. I simply wonder if a lower than prescribed diode voltage (0.65V) for a given I_naught be considered for the case when there is no load resistor. wirefree

Hi, are there any attempts to make a machine readable definition of most common rules and actions (or a causal model) of physical world? I'm looking more a logical level of modelling, at the same level that human common sense works. I have some experience on semantic tecnologies and ontologies...

Hi all. Let's assume I have a situation as following. I have a set of x values containing 10 data points. I also got the corresponding measurement values for that each x data points, as y values, and the error on them. Then, I perform calculations, with let's say 5 different models, in where I...

https://www.upi.com/Science_News/2019/07/30/Mathematical-model-identifies-acoustic-signal-preceding-seismic-shake/4431564489814/

Hi, I wish to write a simple simulation of gas behavior. I have two tanks, connected by a valve. When the valve is opened, the gas will obviously flow and after some time it will reach an equilibrium. I could really do with some help in calculating the rates of change of the temperatures and...

Randall-Sundrum model (https://en.wikipedia.org/wiki/Randall%E2%80%93Sundrum_model) is related to string theory. String theory can be background independent (https://en.wikipedia.org/wiki/Background_independence): "String theory is usually formulated with perturbation theory around a fixed...

The anthropic principle is a philosophical consideration that observations of the universe must be compatible with the conscious and sapient life that observes it. There are two main types of anthropic principle: Weak Anthropic Principle (WAP) and Strong Anthropic Principle (SAP) The Strong...

Hello Everyone! I am interested in examining the case of an isolated Einstein Solid (ES) with a decreasing number of oscillators. The total amount of energy of the ES is considered fixed. Whenever an oscillator abandons our model, it "leaves behind" the amount of energy it contained, so that the...

Hi, I don't know much about the standard model but I'm asking out of interest. Why do we actually need a Lagrangian for the standard model? Surely when you apply the relevant Euler-Lagrange equations, you end up with a variety of equations like the Maxwell equations or Dirac equations. Why...

I have been interested in Seth Lloyd's cosmological model (which proposes that the universe is a some kind of quantum computer or at least similar to it: https://en.wikipedia.org/wiki/Programming_the_Universe, https://arxiv.org/abs/quant-ph/0501135) since long ago. I was wondering if his...

I did the first part using the transfer matrix method: $$ Z = Tr(T^{N}) $$ In this case, the transfer matrix will be $$ T(i,i') = \begin{pmatrix} e^{\beta J} & 1 & e^{-\beta J}\\ 1 &1 &1 \\ e^{-\beta J} & 1 & e^{\beta J} \end{pmatrix} $$ To get the trace of $T^N$, you find the...

Hello! I am trying to model a small pumped hydro energy storage system, with two closed reservoirs (upper and lower). However, I am assuming here that I only know the volume of both reservoirs, the penstock diameter and length, the height difference between both reservoirs, and the turbine...

In This paper we have used Ischemia - Repurfusion in chick embryo to study different markes using Western blot. quoting from Paper Various in vitro and in vivo models are currently available to study I/R mechanism in the brain and other tissues. However, thus far, no in ovo I/R model has been...

Dear all, For an assignment, I am trying to find the relationship between the Sherwood number and the Reynolds number in a channel for different laminar velocity profiles, where there is a concentration of a species at both the top and bottom wall which is transported to the fluid. For this, I...

This took me almost a month to make. It's a CGI model (blender 2.79) of the Colorado lounge, which is part of the Stanley hotel in Estes Park, Colorado. The room was featured in the 1980 Stanley Kubrick horror film "the shining". I was plumb out of ideas for what to make next in 3D, but I saw...

Summary: Can a black hole merger be approximated as a daughter Schwarzschild black hole created when two parent Schwarzschild black holes pack close enough together to trigger a local Schwarzschild radius containing their combined mass? We know that the radius of the event horizon of a...

John's Barrow book "The Constants of Nature" in chapter 13, he talks about a hypothetical multiverse composed of universes governed by other logics. Specifically, he talks about different approaches that physicists take when studying the multiverse, and he mentions a radical approach where even...

This is just to complement some older threads on the topic. The strand model, a conjecture that appears to describe both the standard model and general relativity, has been published. The DOI is http://dx.doi.org/10.1134/S1063779619030055 and the reference is Physics of Particles and Nuclei...

I have a problem about Heisenberg model.When applying mean field approximation,why does the average of spin flip terms be zero(<S+>=<S-> = 0 )? Thanks

I've recently been reading about the 2-dimensional Ising model and its continuum limit from several sources, including https://webhome.weizmann.ac.il/home/fnfal/papers/Ising/lecture1.pdf https://webhome.weizmann.ac.il/home/fnfal/papers/Ising/lecture2.pdf As far as I understood it, the state...

In the Peskin & Schroeder textbook, the ##\beta## function for the Gross-Neveu model is discussed in problem 12.2. After computing it, I have tried checking my results with some solutions found online. My problem is that they all disagree among each other (something quite recurrent for this book...

Summary: I need to Identify my linear model matrix using least squares . The aim is to approach an overdetermined system Matrix [A] by knowing pairs of [x] and [y] input data in the complex space. I need to do a linear model identification using least squared method. My model to identify is a...

Hi so I'm really new to stats, like I know mean, median, mode, and t-testsish and that is it. However, this topic really resonates with me because I know it can have real world applications. So these are my questions. First off here is my real world problem. At my workplace, we sell food that...

Summary: The new HBO miniseries inspired me to use blender 3D to re-create the Chernobyl control room. The HBO miniseries about Chernobyl inspired me use a 3D modeling program called Blender to re-create the RBMK-1000 reactor control room of the Chernobyl nuclear power plant. It's about 95%...

ok guys ! i need to edit this question ! I have an iris type of valve that is installed between the throttle valve and the intake manifold to restrict flow. the valve is to be fully closed and fully opende based on need. there is no partial opening something like that. what i need is the...

I think the answer should be (b) and not (a) because to study the mice model, there should be a gene designed to express the protein of this virus on the cell surface (but I don't know the what it has got to do with puberty ).

As far as I understand, Linearizable Consistency model is a Data-centric and Strong consistency model: Data-centric means: All clients experience the consistency All clients access the same data store All clients experience the same ordering Non-mobile clients. I.e. replica used doesn’t...

ρο/a4 ρο/a3 k Λ Βig Bang Big Crunch Polynomial Expansion Exponential Expansion x 0 x 0 >0 x +1 x +1 x 0 <0 x -1 x -1 >0...

Hi there, studying the Haldane model for my final year project next year, having some trouble understanding how the distant and nearest neighbour hopping works with varying width or height of a 2d sheet in the Haldane model? I'm find some references in papers but they appear to be way over my...

According to the wiki entry 'Kuramoto Model', if we consider the ##N=2## case then the governing equations are $$\frac{d \theta_1}{dt} = \omega_i + \frac{K}{2}\sin(\theta_2 - \theta_1)~~~\text{and}~~~\frac{d \theta_2}{dt} = \omega_i + \frac{K}{2}\sin(\theta_1 - \theta_2),$$ where ##\theta_i##...

Hi, I want to program an GARCH model for exchange rates. To do this, I calculated the residuals. Next, I did the following (in python) def main(): vP0 = (0.1, 0.05, 0.92) a = minimize(garch_loglike, vP0, eps, bounds = ((0.0001, None), (0.0001, None), (0.0001, None))...

Hi, according to ARMA model it is said that in order to check out white noise terms, Ljung-Box is applied involving sum of squared autocorrelations of errors with relevant lags. In short, sum of them is chi-square distribution but n-p-q degree of freedom when we have ARMA(p,0,q) model. My...

Look at the paper in the link below: https://link.springer.com/content/pdf/10.1007%2Fs10701-016-0026-7.pdf It introduces a pilot-wave model on a discrete spacetime lattice. However, the pilot-wave model is not deterministic; the motion of quantum particles is described by a |Ψ|^2-distributed...

Hello, I am currently trying to understand the TUBRNP model which is used to calculate the isotope compositions and the radial power profile evolution with the burnup. I am talking about the basic model (the one from 1994 with only 6 isotopes taken into account) in the case of a LWR with UO2...

Hi there! Is anyone familiar with the Tametire tire model by Michelin? I understand it is based on the brush model and can take into account thermal and pressure properties of a tire. I was able to find only a very basic article online, but not a full description of how this model is able to...

I have an interest in storing, for later use, energy from excess shaft power developed by a wind turbine. Currently I am assuming that the compressor is running in a steady fashion, continually drawing 300K, 1.0 atm. air into the compression chamber and compressing it to 20 atms. before...

Popular reporting: https://www.washingtonpost.com/climate-environment/2019/02/25/very-high-carbon-dioxide-could-suppress-cooling-clouds-climate-change-model-warns/?utm_term=.d40e5e576254 Article in Nature Geoscience: https://www.nature.com/articles/s41561-019-0310-1 (I can see the article, may...

Imagine an half car model with the two suspension and two wheels. There is a torque applied to the rear wheels, that torque create the force between tire/asphalt that pull the car. How that torque react in the main body? I have two hypotesis: 1) It's only internal force that tend to bend the...

In the formulation of Euler-Bernoulli Beam Theory, there are two degrees of freedom at a point, w and dw/dx. Typically, the finite element model of this theory uses cubic polynomial for interpolation of $w$ using a two noded element as given in Chapter 5 of this book [1]. This element is a...

please refer me a good book for the detail step by step study on the second quantization. and also where can I find the jellium model for the metal?

I'm learning about imaging techniques and projection/deprojection for images of galaxies at university. The big issue there is the fact that an image is a 2D representation of a 3D object (for example a galaxy), and to learn some properties of the object you need the 3D structure. What happens...

Hi, I have been reading the Milonni and Eberly book "Laser": in one of the chapters they discuss the Oscillator Model. The treatment is quite straightforward, the Hamiltonian of the process is H=H0+HI where the first term is the "undisturbed" hamiltonian, and the second one is the interaction...

Hi. I'd like to ask what are the differences between Particle Physics, Quantum Field Theory and the Standard Model. I see these names of physics courses but I want to confirm if I understand the difference. My understanding is that when students learn particle physics in their undergraduate...

Homework Statement equations above are descriptive of a system with two configuration variables, q1 and q2. inputs are tau1 and tau2. d and c values are given. the question is about conversion of above equations to a state-space equation where the state-variables are x1 = q1_dot, x2 = q1_2dot...

Does anyone know a model to identify Straight Compact Linear data? I've been toying with Pearson Correlation Coefficient and am very disappointed. https://en.wikipedia.org/wiki/Pearson_correlation_coefficient I originally thought that this would be exactly what I needed, but... After some...

Hi, it's been a long time since I've been on these forums, but here is a new 3D blender model that I spent four weeks of daily work to finish. I'm glad it's done, it wasn't easy. This is metal gear RAY, a 70-foot tall robot from the popular video game franchise metal gear solid.

I calculated FS Model using Mathcad and I got that this part increases with decreasing width $\w$. This make the resistivity increases with decreasing width $\w$. This contradict the result of this model. Has anyone ever come across with this before? the original paper...

I am looking for a comprehensive nonlinear transformer model, which should be available free, readily available for simulation in LTSpice and able to take account of various factors of nonlinear transformer including hysteresis characteristic, skin and proximity effect, leakage inductance...

Homework Statement Using free electron model find the number of electron quantum states per unit volume in ##[\varepsilon_F, \varepsilon_F + \Delta \varepsilon]## energy interval of sodium. Fermi energy of sodium is ##\varepsilon_F = 3.22 eV##, and energy band width is ##\Delta...