In the article, a numerical study of the heat sink with a change in the aggregate state of the oil is carried out. Simulation was carried out in Ansys Fluent CAD for two modes, static - with constant heating of the oil at 340K and dynamic, at which the heating temperature varied with time from 340K to 270K. Heat transfer in the event of a change in the aggregate state of a substance is widely used in cases where it is necessary to achieve the maximum efficiency of heat exchange. In this case, the energy is expended on the phase transition of the substance, for example, to evaporation from the liquid phase. The advantage of the heat-sink design described in this work is a rather high rate of heat transfer, greater resistance to various influences, including mechanical ones, which is primarily ensured by the simplicity of construction, eliminating the drawbacks of classical designs, which are cumbersome (the presence of an external cooling circuit ) and the limited rate of heat transfer.
Keywords: heat dissipation, numerical methods, aggregate state, computational experiment, heat exchange efficiency
This article presents the results of studies on the effect of the erbium chelate complex on the processing of secondary raw materials from polyethylene terephthalate (PET).
Keywords: polyethylene terephthalate, recycling, extrusion, polyisobutylene, chelate complex of erbium.
In the article, the authors carried out a computer experiment in Ansys Fluent CAD to study the efficiency of a heat sink surface in terms of reducing the temperature of a heat-loaded source. Providing optimal thermal conditions for electronic products is one of the most important problems in the design of radio electronic equipment. Increasing the temperature of electronic products significantly reduces the reliability of their work. The work is devoted to numerical modeling of the heat sink surface efficiency of a pin radiator with an internal heat source. A conclusion is drawn about the ineffectiveness of performing a heat sink pin surface, not the entire surface is equally effective.
Keywords: thermal mode of equipment, pin heat sink, numerical methods, aerodynamic flow
The physical and chemical properties of cobalt catalysts for the Fischer-Tropsch synthesis prepared by the method of impregnating a silicate carrier have been studied. The influence of oxide promoters on the specific surface, volume and pore sizes, the degree of reduction of metallic cobalt on the surface of Co-Al2O3 / SiO2 catalyst has been studied.
Keywords: Fischer-Tropsch synthesis, synthetic hydrocarbons, catalyst, cobalt, promoter, carrier, specific surface, porous structure, catalytic activity, degree of reduction
Investigation of the interaction of electromagnetic radiation with molecular systems gives most of the information about their structure and properties. Interpretation of experimental data is directly determined by the knowledge of the structure of energy levels and its change in the transition of these systems to an excited state. A key task of the methods for calculating the molecular orbitals of excited states is to accurately describe the emerging vacancies of the molecular core, leading to radial relaxation of the electron density. A method is proposed for an exact description of the electron density of a molecular system near its nuclei, which provides solutions to the problem of slow convergence of molecular orbitals in a single-center representation. The implementation of the computational procedure is examined using the example of a diatomic hydrogen fluoride molecule. The energy characteristics of the ground and ionized states of the molecule are estimated
Keywords: single-center method, molecular orbital, excited state, ionized state, deep shell
In this paper, we propose a technique for calculation of the thickness. This technique is allowed to determine the thickness of a sleeping bag based on data on the equivalent coefficient of thermal conductivity of a sleeping bag package and data of heat production of person during the sleep. The values and trends in the variation of the relative discrepancy between the calculated and experimental thickness of the sleeping bags as a function of temperature are explained by the possible differences in the data on the thermal conductivity of the down, and by the necessity to introduce thermal insulation coefficients for individual parts of the body.
Keywords: Key words: sleeping bag thickness, down, thermal conductivity, thermal insulation
The parameters of the porous structure and the outer surface of cobalt catalysts for the Fischer-Tropsch synthesis prepared by the water-impregnation method were studied. The effect of the polymorphous modification of the support on the physico-chemical properties of the Co / Al2O3 catalyst was studied.
Keywords: Fischer-Tropsch synthesis, synthetic motor fuel, catalyst, carrier, promoter, polymorphic Al2O3 modifications, elemental analysis, specific surface, porous structure
The necessity of studying the thermal balance of electrons in the ionospheric sporadic E layer to clarify the conditions of its formation in the framework of the theory of the wind shear. The method of calculation of the altitude profile of electron temperature in the sporadic E layer of the ionosphere. Reported satisfactory agreement between the calculated profile of the temperature of the eiectrons and its experimental profile.
Keywords: ionosphere electron, temperature, sporadic layer, heat balance, the heating rate, wind shear, altitude profile of the temperature probe measurements
The paper presents an overview of the existing calculation schemes and the technique for obtaining the angular parts of the matrix elements of the spectroscopic quantities operators with the discussion of cases of complex electron configurations containing nonequivalent electrons. Using the example of a configuration with four unfilled electronic shells, the high efficiency of the technique for constructing wave functions of arbitrary electronic configurations is shown, based on a combination of Slater's determinant approach and the procedure for sequential coupling of orbital and spin moments on the basis of the Clebsch-Gordan coefficients in the LS coupling approximation.
Keywords: Slater determinant, Clebsch-Gordan coefficient, orbital angular momentum, spin moment, 3j-symbol, coefficients of fractional parentage, LS-coupling
The absorbing apparatus serves to extinguish the impact when the wagons cohere and move. Most of the energy, about 80%, in this system is absorbed by a friction unit consisting of a friction wedge and a fixed plate. Absorption of energy in this system occurs due to the work of frictional forces arising during longitudinal motion of the pressure wedge with respect to the friction plate. Due to the large shock-frictional loads, intensive wear and destruction of the cermet cake occurs, which adversely affects the energy capacity of the absorbing apparatus. To eliminate these shortcomings, studies were conducted to create a new material. After numerous experiments, a composition was obtained with the optimum content of components, which maximally satisfies the working conditions of the friction unit and the requirements imposed on these devices.
Keywords: absorbing apparatus, friction unit, cermet, wear resistance, friction plate, powder material, sintering technology
The article deals with the analysis of theoretical cycles of internal combustion engines. Presents Otto cycle, Diesel and Sabate-Trinkler. The theoretical cycle is a closed cycle occurring in the cylinders of the piston engine with its inherent features and assumptions. Each cycle is characterized by two main indicators, such as heat use and efficiency. In this case, the thermal utilization is determined by the thermal efficiency. The estimation of influence of thermodynamic factors on change of thermal efficiency for reception of the best efficiency and the maximum specific work of cycles is resulted. The thermal efficiency of the mixed cycle is obtained. The conclusions of the influence of the compression ratio on the thermal efficiency are presented. A comparison' of different theoretical cycles from the point of view of their cost-effectiveness and efficiency under the same conditions.
Keywords: internal combustion engine, ideal cycle, thermal efficiency, thermal processes
The article gives an overview of the ways to utilize the heat of the boiler exhaust gases. In conditions of actualization (both technical and economic expediency) of application of technologies for fuel economy and environmental protection, the use of aggregates based on the internal combustion engine and microturbines with the utilization of the heat of the cooling system and exhaust gases has found application. Deep cooling of combustion products of natural gas both in boilers (condensing boilers) and in special condensing heat exchangers (utilizers) makes it possible not only to organize the full utilization of the physical heat of the flue gases (the lowest heat of combustion of the fuel), but also to select the latent heat of condensation Water vapor. The coefficient of efficiency of the boiler-aggregate will be increased in this mode by 8-12%, provided that the boiler operates in the optimal mode. Cooling of combustion products also reduces the content of nitrogen oxides in flue gases, incl. With the use of heat pump plants. The efficiency of the implementation of projects for the installation of condensing heat exchangers depends to a large extent on the number of hours of operation at maximum capacity in the mode of deep utilization. In this connection, we propose a variant of optimization of the boiler room thermal scheme with the heat recovery of the flue gases.
Keywords: Heat recovery boiler, boiler house thermal scheme, optimization, boiler, flue gases, heat generating unit
The questions of desorption of the elemental composition of glass during processing with an electron beam is discussed. Sample silicate glasses prepared by standard technology were studied after polishing by electron beam processing (EBP). Calculated estimates showed that the depth of the surface depletion layer of weakly alkaline elements reaches 20-50 nm. Herewith the temperature front reaches the machining depth of 50 µm.
Keywords: electron-beam, glass, diffusion, desorption, microsystems
The article presents the results of the use of viscous additives based on polyisobutylene to improve the performance of railway greases LZ CNII. It is established that the introduction of this type of additives into the dispersion medium of lubricants allows to increase their colloidal stability and tribological properties without deterioration of the operational parameters essential for the application of these lubricants.
Keywords: plastic lubricant, friction, thickener, polyisobutylene, wear resistance, grease film, reliability
A comparative analysis of the methods of heat engineering calculation and an assessment of the efficiency of heat exchange in frame-panel housing construction are presented.
Keywords: Skeleton-panel housing construction, air permeability, heat exchange efficiency, heat and moisture regime
Concentration changes in the frequencies of Raman spectra in binary salt molten alkali metal systems with a common cation Li / ClO4, NO3 are shown. An antibiotic change in the frequencies of stretching vibrations is noted.
Keywords: Concentration changes in the frequencies of Raman spectra in binary salt molten alkali metal systems with a common cation Li / ClO4, NO3 are shown. An antibiotic change in the frequencies of stretching vibrations is noted
An experimental device designed for the detection of peripheral veins during the injection and infusion was developed on the basis of recording the difference in the intensity of the optical signal reflected from the vessels and surrounding tissues. The device allows to perform the detection of the locations of vessels, to determine their projection, to confidently distinguish veins and arteries. The effectiveness of the application is shown in tests on healthy people and patients with diabetic angiopathy. The device is very compact, has a simple design and low cost.
Keywords: infrared light, optical pair, photodiode, LED, introscopy, vascular detection, complicated intravenous access, peripheral vein, photoplethysmography, angiopathy
In this paper, the effectiveness of implementing DSP algorithms necessary to realize the fact of glass breaking in a controlled room is considered. In the course of the research, existing schemes for constructing glassbreak detectors used in existing fire and security alarm systems are analyzed. The possibility of constructing digital filtering algorithms on microcontrollers STM32F4XX of medium degree of integration is investigated. Studies have shown the fundamental possibility of implementing DSP algorithms necessary to detect the fact of glass breaking on STM32F4XX microcontrollers in real time.
Keywords: digital signal processing, burglar alarm system, glass break detector, digital filter, finite impulse response, microcontroller performance.
Flat multicolor light rasters larger sizes can be used for orientation of the aircraft relative to the runway. In the case of the use of such light vehicles in the route and glide-path system (KGF) landing aircraft to increased demands. It should be reliable, efficient, weatherproof and safe. The safety of the pilot is of importance both from the point of view of security applications of KGF as avionics, and increasing psychological and emotional stress, and richness of information flows. As well as the reliability of the system is a guarantee of minimization of emergency situations, leading to the work of the pilot in a stressful condition when a person has reduced functional performance (reduced attention, drops his concentration), speed of decision making and actions can be reduced and, accordingly, affect the results of its activities. Despite the high level of automation of process of landing of an aircraft on the runway, visual perception a pilot environment remains a key in taking a final decision. A particularly acute problem when landing on small platforms, including on the platforms of shipborne. The sooner the pilot will visually assess the environment, the more time it will have for decision-making, especially in conditions of poor visibility and the presence of radio interference.
Keywords: the light raster, semiconductor lasers, galvanoscanner, line scan, frame scan, sector, raster geometry raster, route and glide-path system
The article analyzes the adaptation contour, which is an integral level of management of the body's hematopoietic system, aimed at optimal maintenance of the body's metabolism as a whole. It is indicated that for complex measurement problems it is advisable to use the principles of constructing measuring systems, formulated in terms of system functions using the fractal-categorical approach. It is concluded that the functorial and category maps make the analysis of the hematopoiesis process more complete and visual, and the possibility of further decomposition allows the researcher to carry out more detailed research, visually displays the processes of adaptation of the organism under external influences and naturally contributes to the construction of automated measuring systems for which the adaptive The contour is a model of the bioconverter of information on the processes of hematopoiesis included in composition of bioinstrumental measuring system
Keywords: structural and analytical method, information-measuring system, information flows, hematopoietic system, category diagram, functors, adaptation contour, bioinstrumental information-measuring system, control signal, measurements
To significantly increase the accuracy of measurement and the reproducibility of the results, a method has been developed for determining the decrease in illumination of filamentary LED lamps. The necessity and possibility of realization of the first reading of illumination in one second is grounded.
Keywords: filament lamp, illumination recession, method, error, criterial value, rate of decline
The paper is devoted to an overview of the methods of ice characteristics of water bodies studies (such as an indicator of the ice cover, the timing and duration of the phases of ice regime). The advantages of the use of multispectral satellite imagery to assess ice conditions of water bodies over the other methods are listed. The difficulties of obtaining data on a particular water body under study are shown. These difficulties appear because of the identification problems of the water body when interpreting satellite images (maps).
Keywords: ice characteristics, water, earth remote sensing, interpretation, multispectral imagery
In work methods of generation of an optoacoustic signal for studying biological tissues are considered, the advantages of the method are shown. Ultrasound studies of biotissues are based on the detection of mechanical properties in biological tissues, ultrasonic methods do not allow to establish the level of oxygen saturation or hemoglobin concentration. Optoacoustic methods can allow to determine the properties of tissues and give images with high contrast at high ultrasound resolution in relatively large volumes of biological tissues.
Keywords: optoacoustics, optoacoustic waves, biofluids, spherical sources, absorption, oxygen saturation, near field, far field