New approximate formula for Arrhenius temperature integral

In this paper a more precise approximate formula for Arrhenius temperature integral, i.e., -ln P(u) = 0.37773896 + 1.89466100 ln u + 1.00145033u, is proposed, by using two-step linearly fitting process: (i) the linear dependence of d ln p(u)ldu on 1/u and (ii) the linear dependence of (ln p(u) - c ln u) on u. Values of p(u) at different u were directly obtained from numerical integration of temperature integral without derivation from any approximating infinite series, and values of d In p(u)ldu were obtained by numerical differentiating. New equation for the evaluation of non-isothermal kinetic parameters has been obtained from the above dependence, which can be put in the form ln[g(alpha)/T-1.89466100] = [ln AE/betaR + 3.63504095 - 1.89466100 ln E] - 1.00145033E/RT The validity of this formula was confirmed and its deviation from the values of numerical integrating was discussed. Compared with some previously published approximate formulae, our formula has the best result in the kinetics analysis of non-isothermal process. (C) 2003 Elsevier B.V. All rights reserved.