The dynamics of chemical reaction networks often takes place on widely differing time scales--from the order of nanoseconds to the order of several days. This is particularly true for gene regulatory networks, which are modeled by chemical kinetics. Multiple time scales in mathematical models often lead to serious computational difficulties, such as numerical stiffness in the case of differenti...

the effect of mechanical activation on structural changes and kinetics of carbothermic reduction of hematite with graphite was studied in this research. hematite powder mixture with graphite (with stoichiometry ratio c/o=1) was milled for the time periods of zero to 50 hours, and the structural changes were studied using x ray diffraction (xrd). the effect of mechanical activation on the kineti...

Sucrose is applied as an efficient catalyst for the three-component reaction consisting of aromatic aldehydes, malononitrile and resorcinol in a mixture of water and ethanol media as green solvents. The advantages of this method are excellent yeild, inexpensive catalyst and more environmentally friendly. Mechanistic insight into the synthesis of 2-amino-4H-chromene included spectral kinetics ap...

In this work, experimental kinetics data of methane hydrate decomposition at temperatures ranging from 272.15 to 276.15 K and at pressures ranging from 10 to 30 bars were modeled by using chemical affinity. This model proposed a macroscopic model which is independent of any intermediate mechanism like heat or mass transfer. The results show there is good agreement with experimental data. Al...

The spontaneous and pepsin-catalyzed activation of pepsinogen has been observed and analyzed kinetically. At appropriate protein concentrations (1 mg per ml or less), a kinetically first order reaction was observed in the pH range 1 to 3, implying an intramolecular activation mechanism. Substantiation of the first order reaction came from a linear plot of log pepsinogen concentration versus tim...

Molecular dynamics simulations are used to study the mechanism and kinetics of hydrated electron diffusion. The electron center of mass is found to exhibit Brownian-type behavior with a diffusion coefficient considerably greater than that of the solvent. As previously postulated by both experimental and theoretical works, the instantaneous response of the electron to the librational motions of ...

Macrocyclic ligands form highly selective and kinetically labile complexes with a wide range of cations, including alkali metal and alkaline earth cations. Formation rate constants are high and remarkably insensitive to ligand structure, but decrease systematically with increasing charge density of the cation this behaviour is qualitatively similar to that expected for the dissociative intercha...

Através da carbamoilação do 2-aminobenzimidazole com diferentes cloroformatos substituídos, sintetizaram-se novos N-[1-(2-amino)benzimidazolil]carbamatos. Estudouse a hidrólise em meio aquoso destes carbamatos numa gama de pH compreendida entre 1 e 13, a uma temperatura de 25 oC. Os parâmetros cinéticos avaliados levaram a concluir que até pH 4 a reação se processa por mecanismo que envolve o a...

The effect of mechanical activation on structural changes and kinetics of carbothermic reduction of hematite with graphite was studied in this research. Hematite powder mixture with graphite (with stoichiometry ratio C/O=1) was milled for the time periods of zero to 50 hours, and the structural changes were studied using X ray diffraction (XRD). The effect of mechanical activation on the kineti...