, D, the amount of a particular substance that diffuses across a unit area in unit time, often obeys the activated transition state theory and its temperature dependence can be expressed by the Arrhenius equation, (22), (23) equation (1):
The resulting calculated diffusion profiles agree reasonably well with the data and yield a single diffusion coefficient
Lastly, changing the water content of the soil will change the diffusion coefficient
and hence the rate at which oxygen can enter the soil and the flux of oxygen for pyrite oxidation (Fig.
Experimental values for the diffusion coefficient
and retardation factor of TMPD-MIB in latex paint are nonexistent in the published literature; hence, a back-calculation of both parameters was obtained using a best fit of the model described herein to experimental data for latex paint applied on gypsum board.
The molecular diffusion coefficient
is proportional to the reciprocal of pressure, 1/P, while the amount of pollutant in a unit volume is proportional to P.
As mentioned earlier, the diffusion coefficient
may be spatially variable to account for local effects (e.
The slow-mode diffusion coefficients
of the polymer aggregates in DMF and DMAc are about 1.
of Aerogel-coated Metal Foam Samples Catalyst used Adsorption Desorption in Sol-Gel diffusion diffusion process coefficient coefficient ([m.
s] is the solid phase effective diffusion coefficient
, which describes the diffusion in the pores of activated carbon, and t is time.
2]D, where D = l9O/p is the diffusion coefficient
Weber determined that the diffusion coefficient
D of sulfur in NR was 0.
Exact expressions also are obtained for the first and second moment of the distribution and the apparent diffusion coefficient
The parameters required to accurately estimate the diffusion coefficient
as a function of temperature for a plasticized cellulose acetate propionate are measured, and theoretical healing times and temperatures are calculated.
In the Knudsen flow regime the diffusion coefficient
is independent of pressure and the governing PDE simplifies to Fick's second law:
At any time, t, the concentration values in the two tanks can be used to calculate the diffusion coefficient
, D, of the drug in the hydrogel from the following equation: