نتایج جستجو برای: atmospheric oxidation
تعداد نتایج: 192737 فیلتر نتایج به سال:
The photooxidation of diethyl ether (C2H5OC2H5) and diisopropyl ether, (CH3)2CHOCH(CH3)2, in the presence of NOx was studied at the European Photoreactor (EUPHORE) in May 1998. The main objective of the experiments was to validate the degradation mechanisms that are based on data obtained from laboratory photoreactor studies. For diisopropyl ether, the experiments provided product yield data th...
The catalytic oxidization of CS2 over atmospheric particles and some oxide catalysts was explored through FT-IR, MS and a fixed-bed stainless steel reactor. The results show that atmospheric particles and some oxide catalysts exhibited considerable oxidizing activities for CS2 at ambient temperature. The reaction products are mainly COS and elemental sulfur, even CO2 on some catalysts. Among th...
Global models of atmospheric mercury generally assume that gas-phase OH and ozone are the main oxidants converting Hg0 to HgII and thus driving mercury deposition to ecosystems. However, thermodynamic considerations argue against the importance of these reactions. We demonstrate here the viability of atomic bromine (Br) as an alternative Hg0 oxidant. We conduct a global 3-D simulation with the ...
The chemical and physical speciation of atmospheric sulfur was investigated in ambient aerosol samples using a combination of sulfur near-edge x-ray fluorescence spectroscopy (S-NEXFS) and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the composition and oxidation state of sulfur in common primary emission sources and ambient particulate matter collected from the ...
The growth in global methane (CH4) concentration, which had been ongoing since the industrial revolution, stalled around the year 2000 before resuming globally in 2007. We evaluate the role of the hydroxyl radical (OH), the major CH4 sink, in the recent CH4 growth. We also examine the influence of systematic uncertainties in OH concentrations on CH4 emissions inferred from atmospheric observati...
INTRODUCTION........................................................................................................................... 1 OVERVIEW OF ATMOSPHERIC VOC OXIDATION ............................................................... 2 CURRENT STATE OF KNOWLEDGE ........................................................................................ 4 Inorganic Reactions.....................
The formation of syngas (H2 and CO) from methane in a rhodium coated monolith is studied as an example for the simulation of reactive ow in a partial oxidation reactor. A tube wall catalytic reactor, which serves as a model for a single pore of the monolithic catalyst, is simulated. The simulation is carried out using a two-dimensional ow eld description coupled with detailed reaction mechanism...
Self-assembled monolayers (SAMs) derived from adsorption of n-alkanethiols onto the surfaces of copper slow the oxidation of the copper surface by ieaction with atmospheric dioxygen. Angstrom-lervel changes in the thickness of the monolayer result in readily observable differences (by X-ray pirotoelectron spectroscopy, XPS) in the rates of oxidation of the copper and adsorbed thiolates. The rat...
The aim of this study was to produce in vitro oxidation products of lycopene, which could be possible in vivo metabolites. An oxidation of lycopene with potassium permanganate gave a range of lycopene degradation compounds resulting from the oxidative cleavage of one or two carbon-carbon double bonds. Eleven apo-lycopenals/ones and six apo-carotendials were obtained and tentatively characterize...
This paper provides an analysis on the various plasma effects on polymers exposed to atmospheric-pressure DBD. Homogeneous diffuse DBD, in symmetrical electrode configuration, working in He and He+O2 is used. The discharge is characterized by electric parameters measurement, whereas the surface is analyzed using contact angle measurement and XPS. The surface modification depends on the level of...
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