# diffusion constant

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## dif·fu·sion co·ef·fi·cient

the mass of material diffusing across a unit area in unit time under a concentration gradient of unity.
Synonym(s): diffusion constant
References in periodicals archive ?
Diffusion constants of PHA hydrogels are between 4.05 x [10.sup.-2] [min.sup.-n] and 7.73 x [10.sup.-2] [min.sup.-n].
In the first step, effective velocities and diffusion constants are determined by solving the Fokker-Planck equation in a force field determined by the Maxwell stress tensor.
So it is necessary to obtain a dimensionless diffusion constant in the following sections.
Jayas, "On the diffusion constant of water in wheat," J.
The same approach has been adopted for the selection of the values for the diffusion constants. On the other hand, essentially the same qualitative result of the dimple formation was obtained for different values around the mean values chosen.
TABLE 6-1 Diffusion constants of soil gases in air and water.
In this model the diffusion constant, D, or more accurately the diffusion coefficient, is assumed constant throughout the decomposition.
The diffusion constant ranged from 153 kg [m.sup.-1] ([+ or -] 25.6 kg [m.sup.-1] at 95% confidence) to 670 kg [m.sup.-1] ([+ or -] 113.6 kg [m.sup.-1] at 95%) as plow depth increased from 20 cm to 40 cm.
The ions then diffuse into the adsorbing particle with a diffusion constant of D.
where c(r,t) is the concentration of diffusing substance at a distance r from the center of the egg mass at time t, [c.sub.1] is the initial uniform concentration of substance, [c.sub.0] is the surface concentration, a is the radius of the sphere, and D is the diffusion constant of the substance.
Small differences in melt temperature will, therefore, greatly affect the diffusion constant and weldability by altering this viscosity term.
where t is time (recorded in days for this paper) and D is the diffusion constant (a measure of the long-term spread of populations).

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