Bulk Nanocrystalline Thermoelectrics Based on Bi-Sb-Te Solid Solution

A nanopowder from p-Bi-Sb-Te with particles ~ 10 nm were fabricated by the ball milling using different technological modes. Cold and hot pressing at different conditions and also SPS process were used for consolidation of the powder into a bulk nanostructure and nanocomposites. The main factors allowing slowing-down of the growth of nanograins as a result of recrystallization are the reduction of the temperature and of the duration of the pressing, the increase of the pressure, as well as addition of small value additives (like MoS2, thermally expanded graphite or fullerenes). It was reached the thermoelectric figure of merit ZT=1.22 (at 360 K) in the bulk nanostructure Bi0,4Sb1,6Te3 fabricated by SPS method. Some mechanisms of the improvement of the thermoelectric efficiency in bulk nanocrystalline semiconductors based on BixSb2-xTe3 are studied theoretically. The reduction of nanograin size can lead to improvement of the thermoelectric figure of merit. The theoretical dependence of the electric and heat conductivities and the thermoelectric power as the function of nanograins size in BixSb2-xTe3 bulk nanostructure are quite accurately correlates with the experimental data.Comment: 35 pages, 24 figures, 4 tables, 52 reference

The effectiveness of modern technologies of secondary opening of productive horizons and the ways of its improvement

The technologies of secondary penetration of productive formations are considered. Main factors affecting the efficiency of technologies in well completion and operation are shown

Stabilization of Disintegrating Ferroalloy and Steelmaking Slags

High-basic refinery slags are susceptible to silicate disintegration and turn into powder at cooling, and it is the cause of a negative impact of slag disintegration products on the environment. An applied method of slag disintegration preventing is the stabilization of its structure in the process of formation or cooling. The crystallographic method of stabilization of disintegrating slags lies in introducing micro additives into the slag composition. To realize the thermal method of slag stabilization, a rotor-type installation with a ball piece is proposed. Approbation of the applied methods of disintegrating slag stabilization showed their efficiency for producing a material with a number of new technological properties and uses. Keywords: disintegrating slags, stabilization, micro additives, rotor-type installatio

Depression of the ULF geomagnetic pulsation related to ionospheric irregularities

We consider a depression in intensity of ULF magnetic pulsations, which is observed on the ground surface due to appearance of the irregularities in the ionosphere. It is supposed that oblique Alfven waves in the ULF frequency range are downgoing from the magnetosphere and the horizontal irregularities of ionospheric conductivity are created by upgoing atmospheric gravity waves from seismic source. Unlike the companion paper by Molchanov et al. (2003), we used a simple model of the ionospheric layer but took into consideration the lateral inhomogeneity of the perturbation region in the ionosphere. It is shown that ULF intensity could be essentially decreased for frequencies f = 0.001-0.1 Hz at nighttime but the change is negligible at daytime in coincidence with observational results

Circadian rhythm of carbohydrate metabolism in health and disease

The article presents a review of the main circadian mechanisms regulating carbohydrate metabolism and their role in maintenance of energy homeostasis; the molecular genetic structure of the circadian system is also discussed. The role of adipose tissue and other organs and systems in the maintenance of circadian rhythm of carbohydrate metabolism, both in health and in obesity and diabetes, is highlighted. Particular attention is paid to diurnal rhythms of endocrine factors responsible for metabolic patterns of hormones such as cortisol, growth hormone and melatonin. Gender differences in the circadian regulation of energy and carbohydrate metabolism are also discussed, as well as their changes in different age periods. Article provides detailed review of the mechanisms of glucose utilization, reactivity of the pancreatic islets and peripheral insulin sensitivity shifts at different time periods of the day in people with normal body weight, android and gynoid types of obesity, both in women and men. Protective factors of energy metabolism circadian regulation structure preventing the development of diabetes mellitus and cardiovascular disease in individuals with so-called “metabolically healthy” obesity type are discussed. Article provides a review of various pathways of circadian rhythm disturbances, mechanisms of their development, as well as exogenous and endogenous factors leading to carbohydrate metabolic circadian rhythm misalignment, such as shift work, untiming of natural and artificial lighting, jet lags, sleep disorders. Represented data contribute to a new look at the pathogenesis of obesity and carbohydrate metabolism disorders in various types of obesity in men and women, that provides basis for searching for new effective methods of prevention and treatment of these conditions, elaboration of evidence-based diets and physical activity recommendations, as well as approaches to their medical treatment

Disappearance of aligning properties of deposited SiOx films as caused by external factors

Thermal and degradation stability of SiOx aligning films deposited by cathode reactive sputtering (CRS) in glow discharge plasma were investigated. It was shown that a heat treatment and other external factors initiate transformations on the surface of aligning film and provided new conditions at the interface. This leads to a change of slight axis orientation direction of LC molecules and appearance of various defects in the LC aligned structures. The technological ways to increase the aligning layer durability under influence of external factors were proposed