نتایج جستجو برای: conversion kinetics
تعداد نتایج: 207514 فیلتر نتایج به سال:
Here we describe a preliminary investigation on the ability of natural keratin to catalyze the nitroaldol (Henry) reaction between aldehydes and nitroalkanes. Both aromatic and heteroaromatic aldehydes bearing strong or moderate electron-withdrawing groups were converted into the corresponding β-nitroalcohol products in both DMSO and in water in the presence of tetrabutylammonium bromide (TBAB)...
Perovskite solar cells (PSCs) have immense potential for high power conversion efficiency with an ease of fabrication procedure. The fundamental understanding of interfacial kinetics in PSCs is crucial for further improving of their photovoltaic performance. Herein we use the current-voltage (J-V) characteristics and impedance spectroscopy (IS) measurements to probe the interfacial kinetics on ...
A simplified approach to the model development and scale-up of a packed bubble column reactor from pilot semi-batch mode to continuous commercial operation has been presented. This is illustrated by choosing the reaction of ethynylation of formaldehyde to 1,4-butynediol for which correct reaction mechanism is difficult to postulate in the compelling safety limitations. The apparent reaction kin...
The kinetics of enzymatic desymmetrisation were analysed for the most common kinetic mechanisms: ternary complex ordered (prochiral ketone reduction); ping-pong second (ketone amination, diol esterification, in half reaction); first (diol ester hydrolysis) and both diacids). For plausible values enzyme parameters, product enantiomeric excess (ee) can decline substantially as reaction proceeds t...
BACKGROUND The systemic availability of oral/dietary arginine and its utilization for nitric oxide (NO) synthesis remains unknown and may be related to a competitive hydrolysis of arginine into urea in the splanchnic area and systemic circulation. OBJECTIVES We investigated the kinetics and dose-dependency of dietary arginine utilization for NO compared with urea synthesis and studied the cha...
Thimerosal (TM) is an ethylmercury (etHg)-containing preservative used in some vaccines despite very limited knowledge on the kinetics and direct interaction/effects in mammals׳ tissues after exposure. Thus, this study aimed to evaluate the kinetics of Hg species in mice in a time course analysis after intramuscular injection of TM, by estimating Hg half-lives in blood and tissues. Mice were ex...
The pyrolysis behavior and kinetics of the aqueous fraction of bio-oil were studied through thermogravimetric (TG) analysis. Based on the experimental data, activation energies and kinetic parameters were calculated by the Achar differential method and the Coats-Redfern integral method, then the most probable mechanism functions and kinetics model were obtained at last. The results show that th...
The previous papers of this series (Bray, Thorpe & White, 1951, 1952e; Bray, Humphris, Thorpe, White & Wood, 1952b, c, d) reported a study of the kinetics in vivo of some reactions involving benzoic acid and some of its precursors, certain precursors of phenols and a series of substituted phenols. A mathematical model was worked out which could account for the effect upon metabolic fate of dose...
This paper deals with the design of a feedback controller for fed-batch microbial conversion processes that forces the substrate concentration C(S) to a desired setpoint, starting from an arbitrary (initial) substrate concentration when non-monotonic growth kinetics apply. This problem is representative for a lot of industrial fermentation processes, with the baker's yeast fermentation as a wel...
Reversible addition-fragmentation chain transfer polymerization (RAFT) was used to prepare polymer brushes grafted onto silica nanoparticles. Novel RAFT-silane agents were prepared that contained both an active RAFT moiety and a silane coupling agent. RAFT agents were anchored to silica nanoparticles by the functionalization of colloidal silica with the RAFT-silane agents. RAFT polymerizations ...
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