Questions tagged [diffusion]

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How the 3M Aura 9332+ masks filtrate airborne particles/virus?

The 3M Aura 9332+ mask is labeled FFP3 which means that it filters at least 99% of airborne particles. This article mentions that N95 masks (which filtrate 95% of airborne particles) filtrate the ...
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1answer
24 views

P-N junction depletion region

Before I explain my problem I'd like to mention I'm still green and about 2 weeks into these topics. I learned most of it from youtube videos, wikipedia and other science sites, so I'll be explaining ...
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1answer
85 views

What is the difference between a diffuser and a duct in turbines?

I have been reading this paper, which addresses the advantages of diffusers in cross flow turbines. The abstract says (emphasis is mine): A CP’s extraordinary improving resulted when yaw increased ...
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2answers
39 views

Diffusion of miscible fluids

I was trying to model experimentally the interdiffusion of two miscible liquids. Is there an optical method to find out the extent of diffusion; the addition of fluorescing agent into any of the two ...
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0answers
26 views

How to calculate the Jacobi of electron/hole continuity equations for semiconductors with respect to potential when applying Newton's method?

These are the discretized drift diffusion equations as taken from the book "Analysis and Simulation of Semiconductor Devices" by Siegfried Selberherr. The electron continuity equation is: $$\begin{...
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0answers
195 views

How is the reaction progress variable $c$ coupled with Temperature equation while solving the SIMPLE algorithm in CFD?

While solving the Navier-Stokes equation using SIMPLE algorithm, we solve the transport equation for additional scalar at the last step according to the SIMPLE's procedure. We need to add a new ...
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2answers
2k views

Derivation of Overall Mass Transfer Coefficient

The flux in the gas can be written as: $$N_{1}=k_{p}(p_{1}-p_{1i})$$ And the flux in the liquid can be written as: $$N_{1}=k_{x}(x_{1i}-x_{1})$$ And we know that $$x^*_{1}=\frac{p_{1}}{H}$$ How ...
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1answer
187 views

Waterproof Case Time Limits

Some cell phone cases have a waterproof rating of IP-68, often specifying that they can tolerate immersion to 6 feet for 30 minutes or 3 feet for 60 minutes. My understanding, however, is that a good ...
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1answer
89 views

How long does it take for two initially seperate fluids to reach a certain homogenity across their container?

Imagine the following initial condition: Two completely miscible fluids A and B with different dynamic viscosities $\eta_A$ and $\eta_B$ are seperated in a container with fixed Volume $V_0$ and ...