نتایج جستجو برای: toluene and xylene
تعداد نتایج: 16828906 فیلتر نتایج به سال:
Background and purpose: Biological monitoring for workers exposed to solvents includes complementary environmental monitoring which is useful in toxic chemical risk assessments. The aim of this study was environmental and biological monitoring of workers exposed to volatile organic compounds (VOCs) in petrochemical industry. Material and Methods: Air and urine samples were collected from 104 i...
Enthalpies of dissolution of C60 and C70 in o-xylene, toluene, and CS2 have been measured by a Calvet MS-80 microcalorimeter at temperatures from 293.15 K to 313.15 K. It was observed that the dissolution of C60 in the three organic solvents in the above range of temperatures was exothermic, while the dissolution of C70 in the same three solvents was endothermic. The enthalpy of dissolution of ...
The objective of present study was to identify volatile organic compounds (VOCs) emitted from several sources (fuels, traffic, landfills, coffee roasting, a street-food laboratory, building work, indoor use of incense and candles, a dental laboratory, etc.) located in Palermo (Italy) by using canister autosamplers and gas chromatography-mass spectrometry (GC-MS) technique. In this study, 181 VO...
Shape selective xylene production is very important in the polymer industry because of its extensive use as raw material for monomer preparation. The acidity associated with the Lewis and Broensted centers present in the pillars interlayered clay and its textural properties allows good catalytic activity and shape selectivity toward p-xylene production. So, in the present study, ultrasonic and ...
The municipal solid waste (MSW) landfill is recognized as an anthropogenic source of air pollutants that can have a negative impact on human health and the environment. Workers who work at MSW may be exposed to risk due inhalation substances such volatile organic compounds (VOCs). Although VOCs account for 1% in gas, they are important because high level toxicity associated with them. Regular m...
New photographs of the far ultra-violet spectrum of benzene are presented. The absorption from 2000 to 1800A (Amlx, c. 1980A) is regarded not as a part of the much stronger absorp tion of peak at 1790 A but as due to a separate transition. Sharp bands lying at 1790 A represent the first member of a previously reported Rydberg series. The spectra of toluene, xylene, monochloroando-dichlorobenze...
Pseudomonas putida mt-2 carries a plasmid (TOL, pWWO) which codes for a single set of enzymes responsible for the catabolism of toluene and m- and p-xylene to central metabolites by way of benzoate and m- and p-toluate, respectively, and subsequently by a meta cleavage pathway. Characterization of strains with mutations in structural genes of this pathway demonstrates that the inducers of the e...
Quartz crystal nanobalance (QCN) sensors are considered as powerful masssensitive sensors to determine materials in the sub-nanogram level. In this study, a single piezoelectric quartz crystal nanobalance modified with polystyrene was employed to detect benzene, toluene, ethylbenzene and xylene (BTEX compounds). The frequency shift of the QCN sensor was found to be linear against the BTEX compo...
Methyl bromide (CH3Br) and methyl chloride (CH3Cl) are important precursors for destruction of stratospheric ozone, and oceanic uptake is an important component of the biogeochemical cycle of these methyl halides. In an effort to identify and characterize the organisms mediating halocarbon biodegradation, we surveyed the effect of potential cometabolic substrates on CH3Br biodegradation using a...
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