Complex processing of fluorine-containing wastes of fluorite ores

The possibility of processing fluorine-containing wastes of fluorite ore, which include fluorite, calcite, quartz, and anorthite, has been investigated. A manufacturing flow chart of the complex processing of the ore waste materials with the production of sodium fluoride, alumina, soda ash, and raw materials suitable for the production of Portland cement and wollastonite is suggested.     

Removal of impurities from liquid solutions by vacuum desorption with solvent evaporation

Mass transfer with solvent evaporation in the vapor-liquid two-phase film evaporators used for the removal of undesirable impurities from liquid solutions at low pressure is studied. The average concentrations of solution components in the falling liquid film are determined. The most efficient operating conditions for impurity removal, in which the resistance to mass transfer is concentrated in the liquid phase, are found. Original Russian Text ? V.N. Babak, T.B. Babak, L.P. Kholpanov, 2008, published in Teoreticheskie Osnovy Khimicheskoi Tekhnologii, 2008, Vol. 42, No. 6, pp. 654–670.     

Some sulfides of gold and silver: Composition,mineral mineral assemblage,and conditions of formation

Characteristic mineral assemblage and special features of the composition of Au and Ag sulfides of gold-silver deposits have been established. The forms of the occurrence of Au and Ag in the minerals of the early and last stages have been analyzed. The conditions for the formation of uytenbogaardtite and petrovskaite in supergene and low-temperature hydrothermal processes have been considered. A thermodynamic model explaining their genesis in the oxidation zones is presented.     

Kinetics of the reaction of olefin synthesis from methanol and dimethyl ether

The kinetics of the reaction of olefin synthesis from dimethyl ether and methanol is studied. A kinetic model of the nine-route reaction under study is constructed. The constants of the model are estimated using experimental data. The adequacy of the model to the results of experiments is shown     

Integrated carbon nanotube field emission differential amplifier: Modeling and measurement of the common-mode rejection ratio

A novel integrated vacuum field emission (VFE) differential amplifier (diff-amp) utilizing carbon nanotube (CNT) emitters has been developed. A dual-mask microfabrication process was employed to achieve a VFE diff-amp by integrating identical CNT VFE transistors with built-in split gates and integrated anodes. The identical pair of triode amplifiers was well-matched in their device characteristics. The measured ac small-signal characteristics of the diff-amp showed a common-mode-rejection ratio (CMRR) of ~ 320 (~ 50 dB). The proposed analytical model of the CMRR was verified to be in good agreement with the experimental data. The successful implementation of the CNT diff-amp demonstrates a new way to achieve temperature and radiation tolerant VFE integrated microelectronics.     

Use of sequential x-ray fluorescence analysis for solving analytical problems in the glass industry

The capabilities of x-ray spectral instruments for fast analysis of raw materials and glass and ceramics were demonstrated. The range of the content of determinable elements in a sample ranges from 1 ppm to 100%. The measurement time is 10–15 sec.     

Oxidation of carbon nanofibers and materials obtained on their basis

The results of the oxidation of carbon nanofibers and materials obtained on their basis are presented; these results demonstrate that the nanofibers were formed by carbon with different degrees of crystal structure ordering. The experimental data supported previous hypotheses that amorphous carbon results from the decomposition of metal carbides. The subsequent formation of spatial structures and the appearance of crystalline carbon species resulted from catalytic graphitization. It was demonstrated that sorbents can be prepared based on carbon nanofibers after pyrolytic consolidation followed by activation, and these sorbents are more effective than well-known sorbents.     

Properties of impregnants from shale phenols

Impregnants prepared from shale phenols for cellular materials had a cohesive strength of 2.4–18.5 J/m² and a specific elongation of 160–170%. The adhesive strength toward a metal was 3.5–6.0 J/m²; in the case of concrete, it was greater than the concrete strength.     

The relationship between bioelectrical impedance phase angle and subjective global assessment in advanced colorectal cancer

Background  

Bioelectrical Impedance (BIA) derived phase angle is increasingly being used as an objective indicator of nutritional status in advanced cancer. Subjective Global Assessment (SGA) is a subjective method of nutritional status. The objective of this study was to investigate the association between BIA derived phase angle and SGA in advanced colorectal cancer.     

Highly heat-resistant mullite-silicon carbide materials

Cross-linking additions of silicon carbide and waste material from ferroalloy production make it possible to increase the heat-resistance index for mullite-containing refractories. For briquette specimens based on a charge containing aluminum powder it reaches 45 thermal cycles (1300°C – water). Translated from Novye Ogneupory, No. 11, pp. 44–46, November 2008.