DEVELOPMENT OF A NONISOTHERMAL METHOD FOR DETERMINATION OF DIFFUSIONAL PARAMETERS

A non-isothermal method for determination of diffusional parameters wa s developed. The dependence of diffusivity on temperature was describe d by an Arrhenius type equation, with the pre-exponential factor and t he activation energy as parameters. These parameters were obtained by optimization of the fit between experimental and theoretical values, u sing the Simplex method of minimization. Equilibrium conditions were d escribed with a constant unit partition coefficient. This model was ap plied to the diffusion of acetic acid into turnips. Results compared w ell with values obtained with the conventional method, using a set of experiments at isothermal conditions. The non-isothermal method has si gnificant advantages, namely the need for much less experimental data and better insight into the statistical significance of the results.