HEAT EXCHANGE IN A PLANE CHANNEL IN A TURBULENT FLOW REGIME IN THE CASE OF SMALL VALUES OF PRANDTL NUMBER ACCORDING TO DATA OF DIRECT NUMERICAL SIMULATION

Using the results obtained by the method of direct numerical simulation of the heat transfer process in a flat channel by various authors, it is shown that at small values of Prandtl number quite a few characteristics of the heat transfer process in a flat channel depend not on Reynolds and Prandtl numbers separately, but on Peclet number. Peclet number is calculated from the so-called dynamic speed

MULTIAGENT SYSTEM OF FORECASTING OF CHAOTIC PROCESSES ON THE BASIS OF STATISTICAL EXTRAPOLATORS

The problem of the of a non-stationary system state predicting is considered. The decision based on the joint processing of the results obtained by a group of independent statistical extrapolators. In the terminology of multiagent systems, each extrapolator is an intelligent agent. The quality of the agent solutions is evaluated on retrospective data and is used as weight characteristic in the problem of a terminal solution estimation. The specificity of non-stationary processes with a chaotic system component leads to the empiricca version of the forecast generation algorithm

THE ANALYSIS OF POSSIBLE FAULTS OF TECHNOLOGICAL PROCESSES IN THE RECOVERY BOILER

The analysis of technological processes for a real control object-a recovery boiler is performed in order to determine faults and possible emergency situations. The recovery boiler is considered as a complex control object (in which a chemical reactor is combined with a steam power boiler), which is advisable to decompose into several interconnected subsystems. The study was carried out in accordance with the HAZOP application manual in the form of a qualitative analysis of faults and possible abnormal situations in the recovery boiler. The study was conducted in accordance with the decomposition of the recovery boiler for each constituent of the interconnected subsystems. As a result of research, for each of the subsystems of the recovery boiler, HAZOP work tables were developed that allow you to identify root frames-linked to specific causes of possible faults.

AN INTELLIGENT INFORMATION SYSTEM DESIGN FOR ANALYSIS AND PREDICTION OF THE DYNAMICS OF RISKS OF THE COMPETITIVENESS OF REGIONS OF THE RUSSIAN FEDERATION

It was revealed that there are no generally accepted methods for assessing competitiveness; modern research is mainly a theoretical analysis of regional competitiveness. It was substantiated that the use of mathematical models and quantitative methods will improve the objectivity of the assessment. A methodology for an information system design for analysis and prediction of the dynamics of risks of competitiveness of regions of the Russian Federation was proposed. The prospects and directions of intellectualization of that system were shown. Based on the analysis of officially published statistical data and information from the regions and the proposed methodology, methods of systematization of socio-economic indicators were designed. An information system module was developed to implement the model based on the Kolmogorov-Chapman equations for assessing the risks of regional competitiveness and its validation was carried out

SYNTHESIS OF ZINC SULFIDE RADIOLUMINESCENT PHOSPHORS WITH USE OF ELECTRONIC BEAM MODIFICATION AND INVESTIGATION OF THEIR PROPERTIES

Synthesized recombination-type zinc sulfide phosphors used in solid-state radioluminescent light sources (SSRLS) are the object of the research. In the course of the study, experimental data were obtained for the first time on the effect of the amount of the incorporated activator on the brightness-spectral characteristics of radioluminescence upon excitation by β-radiation of tritium. Data were obtained on the changes in the radioluminescence parameters under various synthesis conditions, phase composition and electron-beam modification of the crystal structure of the initial phosphors. The results of the work make it possible to find the best light compositions for the use in solid-state radioluminescent light sources

THE MAIN CONCEPTS OF SYNTHESIS OF PEPTIDES AS A NEW GENERATION OF BIOLOGICALLY ACTIVE DRUGS

Currently, peptide-based drugs are increasingly replacing dosage forms which have been widely used for many years due to their affinity for living organisms and greater selectivity to biological targets, which lead to a growing demand. To meet that demand, a method using a solid polymer carrier (solid-phase synthesis), which has no alternative for fast and large-scale synthesis, is used. Nevertheless, work on its improvement is carried out non-stop, not only to optimize the chemical process, but also to bring the process to compliance with environmental standards dictated by modern concepts of green chemistry

INFLUENCE OF VANADIUM OXIDE ADDITIVE ON THERMAL TRANSFORMATIONS OF CERAMIC MASS

A comparative study of thermal transformations of ceramic mass (CM) based on α-Al2O3 modified with vanadium oxide additives introduced into CM by wet mixing and by deposition on the surface of the CM particles using molecular layering nanotechnology was carried out. The structural and chemical transformations of the obtained compositions were characterized by differential thermal analysis under linear heating conditions at a rate of 10°С/min, in the temperature range from room temperature to 1000°C. Changes in the phase composition, specific surface area of the compositions, and the state of the modifying additive before and after heating were studied using x-ray diffraction, low-temperature nitrogen adsorption, and ultraviolet–visible diffuse reflectance spectroscopy

EFFECT OF CALCIUM ON THE ANODIC BEHAVIOR OF ALUMINUM CONDUCTOR ALLOY AlTi0.1 IN THE MEDIUM OF THE ELECTROLYTE NaCl

The article presents the results of an experimental study of the effect of calcium on the anodic behavior of the aluminum alloy AlTi0.1, in the medium of NaCl electrolyte. The study was carried out by the potentiostatic method in the potentiodynamic mode at the potential sweep rate of 2 mV / s. It is shown that the modification of the aluminum alloy AlTi0.1 with calcium promotes the displacement of the potentials of free corrosion, pitting formation, and repassivation to the positive range of values. The corrosion rate of the aluminum alloy AlTi0.1 when modified with 0.01-0.5 wt % calcium decreases by 10-17 %.

SPARK IGNITION EFFECT ON FOAMED FUELS

Experimental research results on the initiation of foamed oil products by electric-discharge plasma are presented. The experimental research simulates the impact of electrostatic charges on foamed oil products and makes it possible to determine their minimum ignition energy. Foamed diesel fuel was chosen as the object of the research. The article shows that when a foamed fuel mixture is exposed to a high-voltage discharge, a physical explosion of the mixture occurs. In that case, there is no ignition of the mixture. The dielectric strength of the foamed fuel mixture is close to the dielectric strength of air

REGULARITIES OF BAYERITE-STRUCTURED ALUMINIUM HYDROXIDE FORMATION DURING PRECIPITATION

Based on published data and experimental studies of formation regularities of aluminium hydroxide, a reproducible technique for synthesis of bayerite-structured aluminium hydroxide by precipitation was developed as a part of the creation of preparation technology of chromia-alumina dehydrogenation catalyst. A possibility of synthesis of high purity bayerite (above 90 wt.%) with different particle sizes depending on synthesis conditions was shown. A correlation between dispersion of the sediments and synthesis temperature was shown, the optimal precipitation temperature – which allows obtaining bayerite with a sufficiently large particle size and high purity – was found. Based on the experiments, a fundamental difference between technologies and products of precipitation by sodium hydroxide and aqueous ammonia was shown. The influence of duration of precipitation stages on the properties of sediments is analyzed from the standpoint of theory of relative supersaturation