Unimolecular β-Hydroxyperoxy Radical Decomposition with OH Recycling in the Photochemical Oxidation of Isoprene

2009 ◽  
Vol 44 (1) ◽  
pp. 250-256 ◽  
Author(s):  
Gabriel da Silva ◽  
Claire Graham ◽  
Zhe-Fei Wang
Keyword(s):  
Photochemical Oxidation ◽  
Radical Decomposition

Photochemical Oxidation of Poly(dimethylsiloxane) Surface and Subsequent Coating with Biomimetic Phosphorylcholine Polymer

2007 ◽  
Vol 2 (2) ◽  
pp. 245-249 ◽  
Author(s):  
Yoshiteru Hamada ◽  
Takao Ono ◽  
Takanori Akagi ◽  
Kazuhiko Ishihara ◽  
Takanori Ichiki
Keyword(s):  
Photochemical Oxidation

scholarly journals End-of-Life Alternatives of Glass Reinforced Polyester Boat Hulls Compared by LCA

2018 ◽  
Vol 27 (4) ◽  
pp. 096369351802700 ◽  
Author(s):  
Mehmet Önal ◽  
Gökdeniz Neşer
Keyword(s):  
End Of Life ◽  
Environmental Impacts ◽  
Raw Materials ◽  
Weight Ratio ◽  
Cost Effective ◽  
Raw Material ◽  
Photochemical Oxidation ◽  
Human Toxicity ◽  
Vacuum Infusion ◽  
Infusion Method

Glass reinforced polyester (GRP), as a thermoset polymer composites, dominates boat building industry with its several advantages such as high strength/weight ratio, cohesiveness, good resistance to environment. However, proper recovering and recycling of GRP boats is became a current environmental requirement that should be met by the related industry. In this study, to propose in a cost effective and environmentally friendly way, Life Cycle Assessment (LCA) has been carried out for six scenarios include two moulding methods (namely Hand Lay-up Method, HLM and Vacuum Infusion Method, VIM) and three End-of-Life (EoL) alternatives(namely Extruding, Incineration and Landfill) for a recreational boat's GRP hulls. A case study from raw materials purchasing phase to disposal/recycling stages has been established taking 11 m length GRP boat hull as the functional unit. Analysis show that in the production phase, the impacts are mainly due to the use of energy (electricity), transport and raw material manufacture. Largest differences between the methods considered (HLM and VIM) can be observed in the factors of marine aquatic ecotoxicity and eutrophication while the closest ones are abiotic depletion, ozon layer depletion and photochemical oxidation. The environmental impact of VIM is much higher than HLM due to its higher energy consumption while vacuum infusion method has lower risk than hand lay-up method in terms of occupational health by using less raw material (resin) in a closed mold. In the comparison of the three EoL techniques, the mechanical way of recycling (granule extruding) shows better environmental impacts except terrestrial ecotoxicity, photochemical oxidation and acidification. Among the EoL alternatives, landfill has the highest environmental impacts except ‘global warming potential’ and ‘human toxicity’ which are the highest in extrusion. The main cause of the impacts of landfill is the transportation needs between the EoL boats and the licenced landfill site. Although it has the higher impact on human toxicity, incineration is the second cleaner alternative of EoL techniques considered in this study. In fact that the similar trend has been observed both in production and EoL phases of the boat. It is obvious that using much more renewable energy mix and greener transportation alternative can reduce the overall impact of the all phases considerably.

Photochemical oxidation of water on a 1 μ Ag+ zeolite layer

1992 ◽  
Vol 69 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Robert Beer ◽  
Frank Binder ◽  
Gion Calzaferri
Keyword(s):  
Photochemical Oxidation

scholarly journals Urban organic aerosol composition in Eastern China differs from North to South: Molecular insight from a liquid chromatography-Orbitrap mass spectrometry study

2019 ◽  
Author(s):  
Kai Wang ◽  
Ru-Jin Huang ◽  
Martin Brüggemann ◽  
Yun Zhang ◽  
Lu Yang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Eastern China ◽  
Organic Aerosol ◽  
Photochemical Oxidation ◽  
Lower Latitude ◽  
Molecular Formula ◽  
Aerosol Composition ◽  
Orbitrap Mass Spectrometry ◽  
Low Degrees

Abstract. Particulate air pollution in China is influencing human health, ecosystem and climate. However, the chemical composition of particulate aerosol, especially of the organic fraction, is still not well understood. In this study, particulate aerosol samples with a diameter ≤ 2.5 μm (PM2.5) were collected in January 2014 in three cities located in Northeast, East and Southeast China, i.e., Changchun, Shanghai and Guangzhou, respectively. Organic aerosol (OA) in the PM2.5 samples was analyzed by ultrahigh performance liquid chromatography (UHPLC) coupled to high-resolution Orbitrap mass spectrometry in both negative mode (ESI−) and positive mode electrospray ionization (ESI+). After a non-target screening including molecular formula assignments, compounds were classified into five groups based on their elemental composition, i.e., CHO, CHON, CHN, CHOS and CHONS. The CHO, CHON and CHN compounds present the dominant signal abundances of 81–99.7 % in the mass spectra and the majority of these compounds were assigned to mono- and polyaromatics, suggesting that anthropogenic emissions are a large source of urban OA in all three cities. However, the chemical characteristics of these compounds varied among different cities. The degree of aromaticity and the number of polyaromatic compounds were significantly higher in samples from Changchun, which could be attributed to the large emissions from residential heating (i.e., coal combustion) during winter time in Northeast China. Moreover, the ESI− analysis showed higher H / C and O / C ratios for organic compounds in Shanghai and Guangzhou compared to samples from Changchun, indicating that OA in lower latitude regions of China experiences more intense photochemical oxidation processes. The majority of sulfur-containing compounds (CHOS and CHONS) in all cities were assigned to aliphatic compounds with low degrees of unsaturation and aromaticity. Again, samples from Shanghai and Guangzhou exhibit a larger chemical similarity but largely differ from those from Changchun.

The Role of the Solvent in Radical Decomposition Reactions: p-Nitrophenylazotris-(p-anisyl)-methane

1954 ◽  
Vol 76 (16) ◽  
pp. 4169-4171 ◽  
Author(s):  
Mendel D. Cohen ◽  
John E. Leffler ◽  
Libero M. Barbato
Keyword(s):  
Decomposition Reactions ◽  
Radical Decomposition

Photochemical oxidation of thiols and copper complexing ligands in estuarine waters

2006 ◽  
Vol 101 (1-2) ◽  
pp. 130-140 ◽  
Author(s):  
Luis M. Laglera ◽  
Constant M.G. van den Berg
Keyword(s):  
Photochemical Oxidation ◽  
Estuarine Waters

scholarly journals Primary Productivity of Phytoplankton in Loch Leven, Kinross

1974 ◽  
Vol 74 ◽  
pp. 157-181 ◽  
Author(s):  
Margaret E. Bindloss
Keyword(s):  
Photosynthetic Capacity ◽  
Photochemical Oxidation ◽  
Light Extinction ◽  
Poor Correlation ◽  
Dark Bottle ◽  
Gross Photosynthesis ◽  
Ph Values ◽  
Photosynthetic Productivity ◽  
Loch Leven ◽  
Crop Density

SynopsisPhotosynthetic productivity of phytoplankton in Loch Leven was studied over a 4-year period (1968–71), using the oxygen light and dark bottle technique. Marked seasonal changes in hourly and daily rates of gross photosynthetic productivity are described within the range 0·02 to 1·59 g O2/m2.h and 0·4 to 21·0 g O2/m2.day respectively. Hourly rates are shown to be relatively insensitive to variations in surface light intensity, whereas daily rates are influenced to a considerable extent by the duration of incident radiation (daylength).The phytoplankton itself exerts a dominant influence on underwater light penetration, accounting for ca 75 per cent of light extinction at highest crop densities. This self-shading effect contributes to the poor correlation observed between crop density and areal gross productivity. The chlorophyll a content per unit area in the euphotic zone often approached its estimated theoretical limit of 430 mg/m2.In general, increase in photosynthetic capacity (per unit content of chlorophyll a) accompanied increase in water temperature. During certain periods an inverse relationship between photosynthetic capacity and population density was evident. Reduction in photosynthetic capacity is attributed, in part, to the high pH values (> 9·5) with concomitant CO2-depIetion associated with dense phytoplankton crops.Estimates of net photosynthetic productivity were frequently zero or negative, even over periods when algal populations were increasing and dissolved oxygen and pH values were above their respective air-equilibrium values. Underestimation of gross photosynthesis due to photochemical oxidation, photorespiration or the use of stationary bottles could not account for this apparent anomaly. The most probable sources of error in the estimates of net photosynthetic productivity are discussed.

Photochemical Oxidation Removal of Hg0 from Flue Gas Containing SO2/NO by an Ultraviolet Irradiation/Hydrogen Peroxide (UV/H2O2) Process

2014 ◽  
Vol 28 (3) ◽  
pp. 2135-2143 ◽  
Author(s):  
Yangxian Liu ◽  
Jun Zhang ◽  
Jianfeng Pan
Keyword(s):  
Hydrogen Peroxide ◽  
Flue Gas ◽  
Ultraviolet Irradiation ◽  
Photochemical Oxidation
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