Questions tagged [diffusion]

For questions referring to the process by which molecules move as a result of their kinetic energy.

9 questions with no upvoted or accepted answers
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How to account for the interface between two different phases in a discretized diffusion model?

I have tried to set up a model for the diffusion of a gas into a liquid. The two media are next to each other and the geometry is spherical because the system should simulate the diffusion out of a ...
4
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0answers
105 views

Reaction-diffusion equation using Lattice-Boltzmann method

I'm struggling to get a working LBM reaction-diffusion implementation. I have a pretty weak mathematics and physics background, and thus I'm having a hard time understanding the notations around the ...
3
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0answers
28 views

Are there materials permeable to oxygen and carbon dioxide but not nitrogen?

Are there materials permeable to $\ce{O2}$ and $\ce{CO2}$ but not $\ce{N2}$? Would this even be possible in theory? Can it be done at even at pressures of 300 atm?
3
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36 views

Cause of imaginary part of Warburg element in EIS

In electrochemical impedance spectroscopy experiments (EIS) the diffusion of electroactive species at flat, macroscopic electrodes is commonly described by the Warburg element with the impedance ...
3
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0answers
41 views

Limit to volume change in a discretized mathematical model?

I have set up a mathematical model describing the diffusion of ozone out of a gas bubble. The bubble is surrounded by a thin gas film. So actually, the model describes the diffusion of ozone through ...
1
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0answers
32 views

Molar flux through membrane

Consider a liquid of pure $\ce{A}$ covered by a composite membrane through which the vapor of $\ce{A}$ is diffusing. The membrane consists of two layers of thickness $l_1$ and $l_2$. The diffusion ...
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0answers
29 views

Diffusion equation I can't seem to find anywhere

So I was looking through some old lecture notes from a few years back when I stumbled upon a useful and simple equation that should, according to my former professor describe the diffusion in solid ...
1
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0answers
59 views

What coefficients can I use in a Reaction-Diffusion Equation?

I am qualitatively analyzing an abstract chemical reaction $A + B \rightarrow 2A$ where $A$ and $B$ are some liquid substances that undergo Reaction-Diffusion with a second order reaction (actually ...
1
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203 views

How to write mass balance equation for the scenario when molecules are getting generated inside an sphere?

I am working on the physical understanding of diffusion through a nano machine(a shell with hollow interior in which molecules are produced) and have taken few assumptions: There is rate $r_T$ with ...