The electronic structure of zinc aluminate (ZnAl2O4) and that of zinc gallate (ZnGa2O4) were studied by the self-consistent tight-binding linearized muffin-tin orbital method with the atomic sphere approximation. The calculated results predict these zinc-based spinel oxides to be direct-gap materials. The direct gap at 0 is found to be 4.11 eV for ZnAl2O4 and 2.79 eV for ZnGa2O4. With reference...

a basic alumina-spinel low cement castable (lcc) composed of sintered bauxite, reactive alumina, calcined alumina, calcined magnesia, microsilica, and high alumina refractory cement was prepared (castable a) to which 5% sodium hexa-meta phosphate was later added (castable b) to prepare samples for heat treatment at 110ºc, 900ºc, and 1400ºc. bulk density (bd), apparent porosity (ap), and cold cr...

Dolomite and magnesite are simple anhydrous calcium and/or magnesium carbonate minerals occurring mostly at Earth surfaces. However, laboratory synthesis of neither species at ambient temperature and pressure conditions has been proven practically possible, and the lack of success was assumed to be related to the strong solvation shells of magnesium ions in aqueous media. Here, we report the sy...

Strontium-90 is a major hazardous contaminant of radioactive wastewater and its processing sludges at many Department of Energy (DOE) facilities. In the past, such contaminated wastewater and sludge have been disposed in soil seepage pits, lagoons, or cribs often under highly perturbed alkaline conditions (pH > 12) where 90Sr solubility is low and its adsorption to surrounding soil is high. As ...

The continuous casting tundish is the last metallurgical reactor where molten metal flows before solidifying in mold. A covering powder can be used for improving steel cleanliness; this case it named ‘active slag’. objective of work to evaluate, laboratory, effect three kinds powders on cleanliness a SAE 1055 modified - Ca-aluminate, Ca-Mg-aluminate, and an Al-silicate powder, analysing their i...

The desilication effects of aluminium sulphate and sodium aluminate on kraft bamboo pulp during the cooking process were investigated in this study. Furthermore, the residual aluminium ion concentration in the resulting black liquor was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES) to evaluate the scaling properties of black liquor during the evaporation process....

A modified commercial (Setaram C80) calorimeter has been used to measure the isobaric volumetric heat capacities of concentrated alkaline sodium aluminate solutions at ionic strengths from (1 to 6) mol kg, with up

The properties of nanocrystalline materials are essentially determined by the grain size and the properties of the grain boundaries of the respective material. Using PAC for the investigation of nanocrystalline materials new information about structural properties and, in case of nanocrystalline semiconductors, electronic properties are obtained. In combination with “classical” experimental tec...

A significant improvement in the production of l-ribulose from inexpensive and commercially available starting materials, L-arabinose and sodium aluminate, is demonstrated. This has facilitated expeditious access to gram-scale quantities of L-ribulofuranoside derivatives.