where D0 is the pre-exponential factor of the Arrhenius
equation (m2
/s), Ea is the activation energy (kJ/mol), R
is the universal gas constant (kJ/molK), and T is the
absolute temperature (K). The natural logarithm of Deff
as a function of the reciprocal of absolute temperature
was plotted in Fig. 4. The results show a linear relationship
due to the Arrhenius type dependence. Eq. (8