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).