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3
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0answers
34 views

Geometric frustration in power transmission networks

I read this article concerning the detection of Braess Paradox on power transmission networks: http://phys.org/news/2012-10-power-grid-blackouts-braess-paradox.html Here is a quote from the article: ...
0
votes
1answer
104 views

1-D Fick's first law - partial derivative?

I've recently been reviewing some concepts, including diffusion. Fick's 1st law: $$J = -D\frac{\partial C(x,t)}{\partial x}$$ as I understand it, applies to the steady state. For 1-D diffusion and ...
0
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1answer
47 views

A cylindrical vessel open at the top

A cylindrical vessel open at the top is 20cm high and 10cm in diameter. Circular hole whose cross-sectional area 1 cm² is cut at the centre of the bottom of the vessel water flows from a tube above it ...
1
vote
3answers
143 views

General Definition of Steady State

According to many sources (including Wikipedia, Stephani&Kluge, D.J. Acheson) a steady state ist: In systems theory, a system in a steady state has numerous properties that are unchanging in ...
1
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0answers
56 views

The steady state theory, can it now be falsified on particle physics grounds, in addition to CMB data?

The steady state theory is no longer taken seriously by most physicists and the Big Bang theory is supported by an enormous amount of evidence, especially the CMB data. But from a quick scan through ...
1
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0answers
39 views

Steady-state solution of Fokker-Planck DE

I have this differential equation: $$\frac{\partial f}{\partial t} = \frac{1}{\tau_s v^2} \frac{\partial}{\partial v}(v^3+v_c^3)f + S$$ It is a Fokker-Planck equation that describes collisional ...
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0answers
55 views

In steady state heat transfer from fins how to choose correct physical situation in numerical applications?

I was solving case for heat dissipation in a turbine blade and it clearly has application for surface convection and insulated tip but correct answer was fetched when tip convection and insulated ...
2
votes
0answers
66 views

Flow between two infinite plates [closed]

I recently got set this problem and I was wondering if anyone would be able to give me some hints/intuition on how to solve it. Thanks. An incompressible thermal conducting fluid is contained between ...
1
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0answers
89 views

Steady State Solution for Carrier Concentration of Intrinsic Silicon in an Electric Field

I'm trying to model carrier action in intrinsic silicon under an applied electric field in one dimension. Taking $n$ and $p$ to be the concentrations of electrons and holes respectively, I got that $...
1
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0answers
81 views

Why is it valid to assume that the liquid-vapour interface is always saturated during evaporation?

For steady state evaporation, I read from two textbooks which simply states that the partial pressure of vapour of interest (say water) at the liquid-vapour interface is equal to the saturation ...
2
votes
0answers
2k views

Steady-state adiabatic nozzle, unknown exit velocity & temperature [closed]

The question is 2.10 taken from: Introductory Chemical Engineering Thermodynamics, 2E by Elliot,Lira Air at 30ºC and 2MPa flows ata steady state in a horizontal pipeline with a velocity of 25m/s. ...
0
votes
0answers
40 views

Interpretation of decay associated difference spetrum

We measured transient absorption spectra and we got $\Delta A(\lambda,t)=A(\lambda,t)-A(\lambda,0)$. If we use DAS (decay associated spectra) for interpretation, we assume that our data have this ...
5
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1answer
11k views

Difference between steady state and equilibrium?

In semiconductor physics, what is the difference between steady state and equilibrium. How analysis of devices varies in these processes?
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2answers
968 views

What is decay associated spectra?

What is decay associated spectra? Suppose we measure the fluorescence intensity over different wavelengths and over time, we get: $$I(\lambda,t) = \sum_i^n \alpha_i(\lambda) \exp(\frac{-t}{\tau_i}).$...
1
vote
1answer
394 views

What happens if we give a single electron charge to a hollow metal sphere?

I found this related question: What happens to 5 electrons on a sphere? But this question describes the case when there can only be 5 electrons on that sphere at all times. The answer linked to the ...