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Unformatted text preview: concentration gradient E. Steady State diffusion occurs when the concentration gradient is stable dx dC D J x-= 1. Flux is defined as the number of atoms diffusing through unit area and per unit time 2. Concentration drives the diffusion rate it is the “driving force” F. Diffusion coefficient 1. D is the measure of mobility of diffusing species 2. D is a strong function of T G. Temperature dependence: follows the Arrhenius equation 1. Q is calculated by determining the slope of the line H. There is a wide range of diffusion coefficients for materials -= RT Q D D d exp ---= 2 1 2 1 1 1 log log 3 . 2 T T D D R Q d...
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- Fall '08
- Thermodynamics, Molecular diffusion, D. Fick, Diffusion- material transport