The aim of the present work was to evaluate with different statistical criteria the suitability of nine equations for describing and optimizing the simultaneous effect of temperature and pH on glucanex activity using two characteristic polysaccharides (curdlan and laminarin) as substrates. The most satisfactory solutions were found with an empirical equation constituted with parameters of pract...

We consider two-dimensional overdamped double-well systems perturbed by white noise. In the weak-noise limit the most probable fluctuational path leading from either point attractor to the separatrix (the most probable escape path, or MPEP} must terminate on the saddle between the two wells. However, as the parameters of a symmetric double-well system are varied, a unique MPEP may bifurcate int...

Self-diffusion coefficient measurements were performed for pure n-alkyl ketone liquids using the pulsed field gradient NMR spin-echo technique. Ionic conductivities and dielectric constants of 0.0055 mol·L-1 tetrabutylammonium trifluoromethanesulfonate in 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone, 2-nonanone, and 2-decanone were also measured. The temperature-dependent conductivities and...

The degradation of branched-chain amino acids (valine, leucine, and isoleucine) in subcritical water was measured from 290 degrees C to 330 degrees C. The degradation process at any temperature obeyed first-order kinetics. The energy of activation for the degradation of each amino acid could be estimated according to the Arrhenius equation. The pH value of the reaction mixture increased during ...

Hydrolysis data for Bis(3-(3,4-dicyanophenoxy)phenyl) phenyl phosphate and Bis(3-(3,4-dicyanophenoxy)phenyl) phenylphosphonate under pH 4, 7 and 10 are presented. Conversion/time plots collected by HPLC analysis, typical chromatograms and NMR spectra of the reactions products are given. Pseudo-first order rate constants are determined for both substrates at 25, 50 and 80 °C. Activation paramete...

Estimating the probability of and mechanism for rare events is a physically relevant and mathematically interesting question. Focussing on issues related to “constrained switching events,” we describe differences from the classical Arrhenius picture and how action minimization can be used as a tool. As a specific example, we turn to the stochastic Allen-Cahn equation and explain recent results ...