The kinetics and mechanism of the reaction between benzaldehyde 1, malononitrile 2 and dimedone 3 in a mixture of ethanol and water as solvents in the presence of fructose as a biodegradable catalyst has been studied by the spectroscopic method (UV-Vis spectrophotometry method). The influence of various parameters (temperature, solvent and concentration) was studied on the reaction by means of ...

it seems that the presence of soil organic matter (som) increases p availability to plants. this effect has commonly been ascribed as competition between the decomposition products of som and p for soil sorption sites resulting in p concentrations increase of soil solution. this study was carried out to obtain information about soil organic matter (som) influence on kinetics and thermodynamics ...

a topical o/w cream containing tretinoin microspheres was prepared. gelatin microspheres of tretinoin were prepared using coacervation method. these microspheres contained about 50% w/w tretinoin. the particle size range of microspheres was between 90-150 m m. in vitro drug release from microspheres and a cream formulation was studied. it was shown that drug release from microspheres followed h...

We describe and interpret computer simulations of the time evolution of a binary alloy on a cubic lattice, with nearest neighbor interactions favoring like pairs of atoms. Initially the atoms are arranged at random; the time evolution proceeds by random interchanges of nearest neighbor pairs, using probabilities compatible with the equilibrium Gibbs distribution at temperature T. For temperatur...

The theory of growth kinetics developed previously is extended to the asym-metric case of oo-critical quenches for systems with a conserved scalar order parameter. In this instance the new parameter M, the average global value of the order parameter, enters the theory. For M = 0 one has critical quenches, while for suuciently large M one approaches the coexistence curve. For all M the theory su...

Ecological, toxicological, and pharmacological research is often concerned with the answer to the question of how a substance is processed within a biological system. The exact knowledge of the corresponding kinetic pattern forms the basis for a useful answer. In order to identify non-linear kinetics, a firstorder approximation method is proposed for complexity-reduction. A simulation study is ...

The digestibility of ether extract varies greatly from forages to grains and further to added fats consisting mainly of triglycerides. This variation has been attributed to two main factors, the presence of nonhydrolyzable substances in the ether extract, especially in leafy foods, and the dilution of endogenous fecal fat. A compilation of results from 188 equine digestion balance observations ...

We conside the kinetics near a first-order poisoning transition for simple surface reaction models which exlude nonreactive desorption. Elucidation of the development and growth of the reactive steady state from a near-poisoned state is achieved via an ‘‘oxidation epidemic’’ analysis of the evolution of an empy patch embedded in the poisoned phase. Associated critical exponents vary strongly wi...

In this research project, the nitrito nitro isomerization of [Co (NH3)5No2]F2 complex has been studied. Isomerization of this complex in the solid state follows a first order kinetics. The rate of isomerization at different temperatures was determined using a Fourier Transform Lnfrared Spectrophotometer. ? and ? are calculated at 298 K. The infrared, visible and ultraviolet spectra of th...