The models tag has no wiki summary.
6
votes
1answer
1k views
LED Thermal Modeling (How to solve heat equation with constant heat source)
I have a mechanical design with LEDs that generate heat. I want to estimate the temperature at the LED junction vs. time, but especially at steady state.
Knowing the LED voltage drop and current, I ...
1
vote
0answers
30 views
is log-Laplace ever an optimal model for physical phenomena?
In the financial world, the log-Laplace distribution almost perfectly models many phenomena such as price changes.
Does this model best fit any physical phenomena?
1
vote
1answer
61 views
Any noise slowly starting to take effects?
I am studying a system subject to random noise, or a system driven by some noise, for example, heat flow or wave propagation perturbed by noise. I would like to know if there is a real system where ...
-2
votes
0answers
16 views
Modeling organic decomposition. [closed]
I am wondering if there is an equation in physics that models organic decomposition using factors like temperature, organic content, etc. I am thinking one exists under the term "chemical potential" ...
0
votes
1answer
115 views
Eddy current losses in electric steel by harmonics of a magnetic field
I am working on an model of a permanent magnet synchronous machine. Right now I am stuck with calculating the eddy current losses caused by the harmonics of the stator magnetic field in the electrical ...
0
votes
0answers
30 views
Examples in physics modelled with a linear ODE [closed]
I have just come across the modeling of an harmonic oscillator that comes out as a linear ordinary differential equation.
As this equations are heavily studied in ODE courses i wonder if there are ...
2
votes
4answers
204 views
Modeling incoming solar radiation
I want to write a model for estimating incoming solar radiation for a specific latitude on earth but I am struggling to find an appropriate source which shows the required equations for doing so. ...
6
votes
1answer
359 views
't Hooft for laypersons
I have looked at some of 't Hooft's recent papers and, unfortunately, they are well beyond my current level of comprehension. The same holds for the discussions that took place on this website. (See, ...
2
votes
1answer
73 views
Is energy always proportional to frequency?
Google has no results found for "energy not proportional to frequency" and many results for E=hf. Is there an example of an energy that is not proportional to frequency?
6
votes
2answers
173 views
Modeling non-quantum objects (in finance, sociology etc) using fermionic fields?
Please provide (if any) applications of fermionic field theory in non-physics macro contexts (finance, sociology etc). I see only bosonic fields being used mostly. The only (minor) application of ...
1
vote
2answers
74 views
Does a scale model with 1/2 the linear length have 1/8 the mass?
If a scale model has 0.5x the original length in all directions, should its mass be 1/8th of the original mass?
2
votes
0answers
101 views
Turboshaft Turbine Mathematical Model
Are there any simplified mathematical models for how two gas coupled turbines (also called a free power turbine) should interact with one another as the speed of the driving turbine changes.
(i.e.) ...
1
vote
1answer
49 views
If a cart hits a wall, does the weight of it affect how it moves, when the center of gravity is constant?
I have a model that represents a bicycle (a wood block with wheels), and I'm balancing the center of gravity so it's the same as a real bike. However, when the center of mass is kept constant, does ...
2
votes
0answers
62 views
Elimination of the node
Recently I have been reading a lot of astronomy papers on reductions in models of the solar system. A reoccurring concept is the elimination of the node. However, they never explain what the node is ...
12
votes
7answers
355 views
Macroscopic laws which haven't been derived from microscopic laws
Can you think of examples where a macroscopic law coexists with a fully known microscopic law, but the former hasn't been derived from the latter (yet)? Or maybe a rule of thumb, which works but ...
1
vote
1answer
254 views
Definition of elementary particle [duplicate]
Possible Duplicate:
Why are atoms particles?
According to wikipedia an elementary particle or fundamental particle is a particle not known to have substructure.
Moreover, I've learned ...
1
vote
0answers
47 views
Modeling the probability of a photodiode measuring photons targets at a neighbor
In current digital cameras, sensors are arrays of photodiodes which "transform" photons energy to electrons. I am aware that the probability of a photon to generate an electron is modeled by a Poisson ...
0
votes
4answers
121 views
What is the simplest system that has both, discontinous and continous phase transitions?
I am looking the simplest system that has both discontinous phase transition and a continous phase transition between the same phases (you can change one parameter).
discontinous transition: first ...
36
votes
7answers
5k views
Why do people categorically dismiss some simple quantum models?
Deterministic models. Clarification of the question:
The problem with these blogs is that people are inclined to start yelling at each other (I admit, I got infected and it's difficult not to raise ...
4
votes
3answers
244 views
Can anyone estimate what proportion of water remains after I flush a toilet?
Imagine I have a clean toilet with some amount of water in the bowl. When I flush the toilet much of that water will be displaced by the tank's water. I want to work out (or model really) what amount ...
1
vote
1answer
192 views
Physics of the electric hot plate
For an electronics experiment, I began wondering about the electric hot-plates (specifically the temperature dependence over time). If I were to measure the given temperature over time, I assume that ...
4
votes
0answers
327 views
Is there any simple quantum model by Gerard 't Hooft which can explain the double slit experiment?
This question is directed to Prof. 't Hooft and anybody who is familiar with his papers. It is a reaction to Prof. 't Hooft's question why nobody is excited about his classical models for quantum ...
3
votes
2answers
91 views
A problem of approximation [duplicate]
Possible Duplicate:
Why are continuum fluid mechanics accurate when constituents are discrete objects of finite size?
When we apply differentiation on charge being conducted with respect to ...
3
votes
4answers
966 views
Bohr's model of an atom doesn't seem to have overcome the drawback of Rutherford's model
We, as high school students have been taught that-because Bohr's model of an atom assigns specific orbits for electrons-that it is better than Rutherford's model. But what Rutherford failed to explain ...
3
votes
4answers
211 views
Formulation of general relativity
EDIT: I think I can pinpoint my confusion a bit better. Here comes my updated question (I'm not sure what the standard way of doing things is - please let me know if I should delete the old version). ...
3
votes
2answers
284 views
Relating the power to weather variables [closed]
Could you please help me in this problem?
I have 3 independent variables, (T,H,t) , as inputs and one output P ( I have all data for these inputs and the output, done experimentally measured every ...
4
votes
0answers
345 views
Interpretation of Stiffness Matrix and Mass Matrix in Finite Element Method
I would like to have a general interpretation of the coefficients of the stiffness matrix that appears in FEM. For instance if we are solving a linear elasticity problem and we modelize the relation ...
3
votes
1answer
89 views
Are there microscopic theories, which work, but which wrongly predict macroscopic behaviour?
Motivated by this question (and the P. W. Anderson article linked in that question, which I came across here somewhere today and just read) I wonder about something, which is somewhat bordering an ...
0
votes
0answers
74 views
References for circular restricted 3 body problem?
Does anyone know of any good references for the CR3BP -- the circular restricted 3 body problem? Emphasizing on real-life applications, and interpretation of the numerical solutions? Thank you. There ...
2
votes
1answer
312 views
The most challenging physical phenomena [closed]
What are examples of endeavors, in the history of mankind, to understand physical phenomena with models which were proved to be incorrect later, reformed significantly, or are still under ...
1
vote
0answers
141 views
Modeling the trajectory of a particle in an Electric field [closed]
[This problem has been resolved, sorry for posting in the wrong forum!]
(I was trying to model the trajectory of a particle in an electric field.)
4
votes
1answer
136 views
Event-by-Event Simulation of Quantum Phenomena
I just recently stumbled over
http://rugth30.phys.rug.nl/dlm/
and
http://www.sbfisica.org.br/bjp/files/v38_26.pdf
As the title suggests these are presentations of mathematical models capable of ...
2
votes
1answer
242 views
Implementing simple atom model using density functional theory (DFT)
I am trying to write computer code which will find the energy and density function for a atom with Z protons and N electrons. I am working in 1D for simplicity and would like to make the overall code ...
3
votes
0answers
172 views
Simple model of the solar system. Parameters? Accuracy?
I was thinking of making a simple 2D model of the solar system, with planets moving along ellipses like
$$x(t) = k_x \sin(t + k_t) (\sin(k_\phi) + \cos(k_\phi))$$
$$y(t) = k_y \cos(t + k_t) ...
3
votes
2answers
301 views
Why are continuum fluid mechanics accurate when constituents are discrete objects of finite size?
Suppose we view fluids classically, i.e., as a collection of molecules (with some finite size) interacting via e&m and gravitational forces. Presumably we model fluids as continuous objects that ...
0
votes
0answers
97 views
Book for learning about constructing correct physical modeling [duplicate]
Possible Duplicate:
List of good classical physics books
I know physics. At least I thought so until I tried to make a model of the system of scales by myself. It was confusing. For example ...
4
votes
3answers
285 views
Guessing what a simple partial differential equation is describing physically
Is there an easy way to look at a partial different equation and get a sense of what kind of phenomena it is physically describing? I have an equation that looks like this:
...
1
vote
0answers
37 views
Conveyor scales modeling [duplicate]
Possible Duplicate:
Conveyor scales modeling
Assume we have a conveyor scales. Which consists of scales, and motor with conveyor belt placed above, so that the boxes can be measured ...
1
vote
1answer
118 views
SDE for particle, PDE for the density
Given a particle on the plane we can assume that it follows 2D Brownian motion. On the other hand if there is a lot of such a Brownian particles one can be interested in the evolution of the density ...
2
votes
2answers
296 views
Software for simulating 3D Newtonian dynamics of simple geometric objects (with force fields)
I'm looking for something short of a molecular dynamics package, where I can build up simple geometric shapes with flexible linkages/etc and simulate the consequences of electrostatic repulsion ...
2
votes
2answers
236 views
Is it meaningful to imagine a sphere uniformly charged with 2e?
If the charge is large, considering charge density is usually meaningful despite the discrete nature of electrical charge. The following sentence is part of a problem in a textbook on ...
3
votes
1answer
191 views
Olympic games and the local g
As you probably know, the two next Olympic games will take place in London and Rio. Randall, author of xkcd, did an interesting observation (that I had never thought of) in http://xkcd.com/852/ , ...
2
votes
1answer
308 views
Modelling noise with distance
I was wondering about the relation between noise with distance, assuming a point source, using sound as the method for communication and air as the medium of communication. Obviously as the distance ...
3
votes
2answers
524 views
Approximating mean daily and hourly temperature beyond Fourier series
Summary: What "well-known" and short parametrized mathematical
function describes daily and hourly temperature for a given location?
If you look at the mean daily temperature graph for a given ...
7
votes
3answers
479 views
Is anyone studying how the topology of space arises from more fundamental notions?
Stephen Wolfram in his book "A New Kind of Science" touches on a model of space itself based on automata theory. That it, he makes some suggestions about modelling not only the behaviour of matter ...
14
votes
5answers
682 views
Relativistic Cellular Automata
Cellular automata provide interesting models of physics: Google Scholar gives more than 25,000 results when searching for "cellular automata" physics.
Google Scholar still gives more than 2.000 ...
1
vote
1answer
300 views
How to model the dynamics of human movement?
I am trying to derive a state space equation for human movement (i.e. walking, running, standing still) in some normal distribution sense. The following equations should not be so hard to follow:
If ...
8
votes
2answers
306 views
Do current models of particle physics explain the chemical properties of elements/compounds?
I have a particle system of seven protons and seven (or sometimes eight) neutrons (each formed by their appropriate quarks, etc.) bound together in a state that can be macroscopically described as a ...
0
votes
1answer
117 views
Computing delta temperature based on radiation and heat loss
Is there a formula that gives me the instantaneous change in temperature under ideal circumstances? Details:
On a cloudless day, temperature is affected by two major things(?):
While the Sun is ...
