The transient preheating process of a regenerative oxidation bed placed in a coal mine methane thermal reverse-flow reactor is numerically investigated in this paper. The regenerative oxidation bed is heated by the burned gas which is generated from a burner and is distributed through manifolds, which is modeled in a three-dimensional, unsteady state and laminar flow system, and is assumed as a...

After SO(2) has entered leaves of spinach (Spinacia oleracea) through open stomata and been hydrated in the aqueous phase of cell walls, the sulfite formed can be oxidized to sulfate by an apoplastic peroxidase that is normally involved in phenol oxidation. The oxidation of sulfite is competitive with the oxidation of phenolics. During sulfite oxidation, the peroxidase is inhibited. In the abse...

Oxidation of histidine by (1)O2 is an important process associated with oxidative damage to proteins during aging, diseases and photodynamic therapy of tumors and jaundice, and photochemical transformations of biological species in the troposphere. However, the oxidation mechanisms and products of histidine differ dramatically in these related environments which range from the gas phase through...

Ammonia-oxidizing bacteria (AOB) can use oxygen and nitrite as electron acceptors. Nitrite reduction by Nitrosomonas is observed under three conditions: (i) hydrogen-dependent denitrification, (ii) anoxic ammonia oxidation with nitrogen dioxide (NO(2)) and (iii) NO(x)-induced aerobic ammonia oxidation. NO(x) molecules play an important role in the conversion of ammonia and nitrite by AOB. Absen...

Manganese (Mn) oxides, which are generally considered biogenic in origin within natural systems, are the only oxidants of Cr(iii) under typical environmental conditions. Yet the influence of Mn biooxide mineral structural evolution on Cr(iii) oxidation under varying geochemical conditions is unknown. In this study we examined the role of light, organic carbon, pH, and the structure of biogenic ...

effects of water on the catalytic performances of movtenbo catalyst in the oxidation of propane to acrylic acid have been investigated at different reaction temperatures and different steam contents. obtained results show that both catalytic performances and catalyst structure are very sensitive to the presence of water vapor in the reaction feed. presence of water induces some structural modif...

The perovskite-structured La2CuO4 nanoparticles have been synthesized via an ultrasonic-assisted co-precipitation route using octanoic acid as organic surfactant, and the phase composition, morphology, lattice parameters and size of nanoparticles are characterized through Fourier transform infrared spectrosco...

nanotechnology is the study of manipulating matter on an atomic and molecular scale. generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension size from 1 to 100 nanometers .  carbon nanotubes have great potentials for novel applications in industry, drug delivery system and many other uses. in this work after purification, multiwa...

The aim of this study was to investigate whether the phases of the menstrual cycle affect lysine requirement in healthy adult females, as determined by the indicator amino acid oxidation (IAAO) method. Five healthy females with regular menstrual cycles were studied at seven graded levels of lysine intake, in random order, with an oral [13C]phenylalanine tracer protocol in both the follicular an...

The reaction of reduced xanthine oxidase with oxygen occurs in two distinct kinetic phases with the rate of the fast phase being about 10 times greater than that of the slow phase. Comparison of transient state and steady state kinetics demonstrates that only the fast phase of oxidation is catalytically significant. The time course of oxidation is quantitatively independent of the following fac...