cerium oxide (ceria) nano particle, as photodegradation prevention agent was studied in water-based polyurethane clear coat  systems. polyurethane coatings show superior weathering resistance compared with acrylic melamine systems. however, any chemical change has detrimental effects on the property profile of pu coatings. coatings containing various amounts of cerium oxide nanoparticles were p...

in this research, the thin films of n-s doped titanium dioxide (tio2) were successfully prepared by simple sol-gel method in the presence of tetrabutylorthotitanate as a starting reagent. furthermore, titanium dioxide (tio2) was functionalized with thiourea. furthermore, n-s doped titanium dioxides (nsto) were fixed on glass balls by glass balls fixed-bed reactor system. besides, the effect of ...

In the continuous gas lift operation, compressed gas is injected into the lower section of tubing through annulus. The produced liquid flow rate is a function of gas injection rate and injection depth. All the equations to determine depth of injection assumes constant density for gas based on an average temperature of surface and bottomhole that decreases the accuracy of gas lift design. Also g...

Compounds characterized by a slow degradation rate in the environment, i.e. resistant to biodegradation, and photolysis processes, are classified as persistent and have often been considered as potential environmental problems. A more exacting approach recognizes that a compound released to the environment has a tendency to accumulate in one medium more than in others. Hence, partitioning, tran...

hartree-fock (hf) and density functional theory (dft) methods employed to study the effect of conformational change on the 13c chemical shifts of 6-mono axial and equatorial substituted and 6,7-di axial-axial, equatorial-equatorial and axial-equatorial substitutedderivatives of 5,6,7,8-tetrahydrodibenzo[a,c]cyclo-octene. the geometry of the conformers have been optimized in the gas phase employ...

Photodegradation of an aqueous solution of Penciclovir (PC, 1) in phosphate buffer (pH 7) under aerobic condition was studied with light of wavelength>270 nm. Three major oxidation products were detected by means of spectroscopic measurements. The products were 4-hydroxy-(3-Hydroxymethyl) butyl spiro imino dihydantion (2), 4[4-hydroxy(3hydroxymethyl)butylamino]-2-imino-1,2-dihydroimidazol-5-one...

perazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid] (Fig. 1) is a broad spectrum fluoroquinolone antibacterial, which is effective against a wide range of Gram-positive and Gram-negative bacteria (1). Fluoroquinolones are sensitive to light (2) and studies have been carried out on the photodegradation of quinolones (3), fluoroquinolones (4), ciprofloxacin (5, 6), sparfloxaci...

Abstract-The photodegradation of two phenylurea herbicides monuron 3-(4-chloropylphenyl)-1,1 dimethylurea) and isoproturon (3-(4isopropylphenyl)-1,1 dimethylurea) in an aqueous solutions containing nitrates (10 M) and nitrites (10 M), using irradiation at 310 nm and at 365 nm respectively is investigated. In both cases MN (10 M) and IP (10 M) photodegradation followed pseudo-first order kinetic...

This work represents the first laboratory study known to the authors describing photochemical behavior of persistent organic pollutants in snow at environmentally relevant concentrations. The snow samples were prepared by shock freezing of the corresponding aqueous solutions in liquid nitrogen and were UV-irradiated in a photochemical cold chamber reactor at -25 degrees C, in which simultaneous...