the thermal degradation of polyethylene (pe) was carried out in the absence and presence ofcatalystes x-zeolite and silica-alumina at different temperatures. the optimum pe/catalysisratio was 0.25:0.05 g/g, which produced highest degradation value. pe and pe/catalysis werecharacterized by thermogravimetric analysis. the thermal degradation properties of polymerhave been studied by infrared spec...

In this research the effects of adding silica and alumina nanoparticles on flow ability and compressive strength of cementitious composites based on Portland cement were investigated. In the first stage, the rheological behavior of different samples containing nanosilica, nanoalumina and polypropylene, polyvinyl alcohol and polyethylene fibers were evaluated. With increasing of nanoparticles in...

Two processes for extracting alumina from low-grade ores are described, one applicable to both clays and high-silica bauxites, and the other only to bauxites. In the former process, a line-containing sinter is prepared and annealed by cooling it slowly through the range of 1,3000 to 1,2000 C. The annealed sinter dusts to a powder which requires no grinding. This material is extracted with a sol...

Tetraethoxy orthosilicate (TEOS) was used not only as a precursor of silica, but also as an agent which reinforces the skeleton of silica-gel to prepare an aerogel and resultant silica and silica-alumina with large pore size and pore volume. In this gel skeletal reinforcement, the strength of silica aerogel skeleton was enhanced by aging with TEOS/2-propanol mixed solution to prevent the shrink...

A highly active heterogeneous Fenton catalyst was fabricated by impregnating iron oxide nanoparticles in alumina coated mesoporous SBA-15 silica.

Examination of clays from surface and basal horizons of four Scottish soils by differential thermal analysis, before and after heating to 600~ and by infra-red spectroscopy indicates that these contain a proportion of highly hydrated amorphous material, resembling allophane in its properties, and that this component is particularly high in clays from the surface horizons with the greatest organ...

The room temperature oxidation of betulin by Cr(VI) compounds in aqueous acetone on solid supports such as alumina, zeolites and silica gel has been studied. The oxidation on alumina support leaded to a single product--betulonic acid--in quantitative yield. One hundred percent selective oxidation during 30 min of betulin up to betulonic aldehyde was determined when silica gel support was used. ...

[BMI][PF(6)] has been supported on silica and alumina in order to study the effect of these classical oxide supports on the structure of the ionic liquid. A widespread characterization by TGA, DSC, XRD and solid NMR of thin films of [BMI][PF(6)] immobilized on these amorphous supports has evidenced a dramatic effect on the ionic liquid structure depending on the nature of the support. For the a...

OBJECTIVE To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. STUDY DESIGN Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al₂O₃-particles); and Group 3: Silica-coating (50 µm silica-modified Al₂O₃-...