Supported metal oxide based olefin metathesis catalysts are widely used in the chemical industry. In comparison to their organometallic catalyst cousins, the oxide catalysts have much lower activity due to the very small fraction of active sites. We report that a simple pretreatment of MoO3/SiO2 and WO3/SiO2 under an olefincontaining atmosphere at elevated temperatures leads to a 100−1000fold i...

Workers in the road construction industry include asphalt plant, ground construction, and road paving workers. These individuals can be exposed to a wide range of potentially hazardous substances. A summary of levels of exposure to different substances measured during road construction is presented. In modern road paving, workers typically are exposed to 0.1 to 2 mg/m3 of bitumen fume, which in...

Metal fiber porous materials with intrinsic properties of metal and functional properties of porous materials have received a great deal of attention in the fundamental research and industry applications. With developments of the preparation technologies and industrial requirements, porous fiber metals with excellent properties are developed and applied in many industry areas, e.g., sound absor...

struggling in world's competitive markets, industries are attempting to upgrade their technologies aiming at improving the quality and minimizing the waste and cutting the price. industry tries to develop their technology in order to improve quality via proactive quality control. this paper studies the possible paint quality in order to reduce the defects through neural network techniques in au...

BACKGROUND L-tryptophan is an important ingredient in medicines, especially in neuromedicines such as antidepressants. Many commercial processes employ various microorganisms with high tryptophan synthase activity to produce L-tryptophan from indole and L-serine, but these processes are very costly due to the costs of precursors, especially L-serine. OBJECTIVES For this reason, we studied the...