degradation of o,o-dimethyl -o-4-nitrophenylphosphorothioate (methylparathion) by ozonation in aqueous solution was studied in a batch reactor under constant ozone dosage and variable ph conditions. the effectiveness of the process was estimated based on the degree of cod (chemical oxygen demand) reduction and conversion of methylparathion. it was observed that ozonation is more effective at a...

Magnetic, Mössbauer, and I.R. studies of nanosize particles of Fe and Co species dispersed in a cage of aluminosilicates structure, in relation to syngas (CO+H2) Fischer Tropsch conversion. The difference in the catalytic activity of such species have shown dependancy on their degree of dispersion. The carbonyl impregnation gave ultra-fine Super Paramagnetic Fe3O4, whereas the nitrate impregnat...

The purpose of this study was to evaluate the correlation between degree of conversion and microhardness in dental composites, as well as the effect of the inorganic content and type of photo-curing unit on these parameters. Three indirect composites (Artglass, Solidex and Zeta LC) were polymerized by means of three different laboratorial units (UniXS, Solidilite and an experimental device). Fo...

Objectives: The study evaluated the bond strength, degree of conversion and fracture pattern hybrid layer in cement-dentin adhesion techniques. Materials Methods: Bovine teeth dentin blocks were divided according to cementation techniques: G1- Conventional three-step adhesive dual-curing resin cement; G2- One-step self-etch G3-Self-adhesive G4- Self-adhesive primer cement. Specimens submitted t...

The aim of this study was to analyse the extent of polymerization of different adhesive films in relation to their permeability. One adhesive of each class was investigated: OptiBond FL; One-Step; Clearfil Protect Bond; and Xeno III. Adhesive films were prepared and cured with XL-2500 (3M ESPE) for 20, 40 or 60 s. Polymerization kinetic curves of the adhesives tested were obtained with differen...