Журнал Сибирского федерального университета. Серия: Техника и технологии @technologies-sfu
Статьи журнала - Журнал Сибирского федерального университета. Серия: Техника и технологии
Все статьи: 1471
Compensation of thermal deformations of heat supply network with radial expansion bends
Статья научная
A methodology for structural analysis of compensation of thermal expansions used for channel or aboveground sections of heat network pipelines with radial expansion bends has been proposed. The methodology is based on the methods of structural mechanics and allows to find technically based dimensions of radial expansion bends. Increased flexibility of the heat pipe angles and stress-raisers of additional bending stresses have been taken into account, the functional and graphical dependencies of the stress caused by thermal deformations of the heat pipe section with the U-shaped radial expansion bends on the temperature of the coolant have been presented. The authors developed and presented the computer program used for calculating radial expansion bends. Due to the program analyzing the model of a heat pipe section with a radial U-shaped expansion bend has been calculated. Comparison of the calculation results with the results obtained by means of the well-known software system “Start” developed by the scientific-and-technological enterprise “Pipeline” has shown a sufficient convergence of results, which confirms the efficiency of the presented methodology and computer program.
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Статья научная
In this study, the data obtained by satellite remote sensing and by studying a mathematical model are combined to investigate seasonal dynamics of wheat and oat agroecosystems with different levels of weed infestation. The study was performed in the south of the Krasnoyarskii Krai. NDVI was used to show the possibility of identifying weed-free and weed-infested crop fields. The model study was based on variations in the initial percentages of the crop and weed biomasses, with plant growth limited by mineral element deficiency. Model prediction of productivity of agroecosystems with different levels of weed infestation showed that the initial weed biomass higher than 30% is critical for crop productivity and may result in considerable crop yield loss.
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Complex approach to the evaluation of the reactivity of solid organic fuels
Статья научная
A universal experiment-calculation approach for the evaluation of the kinetic characteristics of thermochemical transformation of solid organic fuels based on the application of the methods of complex thermal analysis and mathematical simulation has been proposed. The technique of the thermogravimetric experiment data processing and mathematical model description bases itself on a unifi ed calculation scheme of material balances and kinetic processes of natural coal burnout. Satisfactory qualitative and quantitative convergence of experimental and numerical results has been obtained.
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Статья научная
The article deals with the complex computer applications and techniques for solving problems with the fatal errors and synthesis of optimal characteristics of materials and design parameters. A number of examples of typical problems solved these programs and methods.
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Composite multicomponent of gallium pastes-solders
Статья научная
Contact interaction of copper-zinc and copper-silver alloys is investigated with eutectics melts of the system Ga-Zn as composite components of gallium pastes - solders have been revealed. Interaction products have been determined depending on the structure and temperature of contacting components. Structures of developed new low temperature solders have been approved on the basis of gallium.
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Compounding of spent nuclear fuel
Статья научная
The paper resents the results of the research into the processes of extraction of liquid radioactive waste of low and intermediate activity levels from storage and their hardening into inorganic binders (cementation process). The resulting cementing product has a number of advantages: it has high mechanical strength, is non-combustible, radiationally and chemically resistant, and has reduced external radiation of cementitious materials due to high density. Cementation as a technology of conditioning of liquid radioactive waste is a process of immobilization of liquid radioactive waste in cement matrix to obtain a solid fi nal product (cement compound). The paper shows the expediency of using the effects of cavitation technology which is quite easily feasible, energy-efficient, and in some cases has no alternative. The disposal of radiochemical production waste with the decommissioning of nuclear power plants on the basis of cavitation technology increases the productivity of their extraction and the strength of cement compound.
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Computational experiment in the problem of the recent traces of oceanic cosmic impacts
Статья научная
The paper aims to fill the gap between geological practice on the problem of the recent traces of oceanic cosmic impacts and computational experiment on tsunami geology problem. Computational experiment and numerical analysis data of the oceanic comet impacts could be more effective for mega tsunami understanding and prediction than the traditional geological methods. We explored the depositional traces of large-scale water impact on the coast and modeling of mega tsunami given the steep waves and Mach reflection on the rocky shore and described chevron dunes form on the base of neural network technology to solve the inverse tsunami problem. The ocean impact craters were explored using the wavelet analysis digital data of the ocean bottom.
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Статья научная
The results of computer-aided design of deformed semi-finished products manufacturing technological processes for the jewelry chains from new alloys of precious metals production are presented. Algorithms and automated calculations adequacy confirmed by computer simulation and physical modeling of bar rolling and drawing processes. Using data on the mechanical properties of new gold, palladium and silver alloys, patented by the authors, the energy-power equipment load of the subject to the limitations on permissible rolling forces and torques are calculated.
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Concretion onyx of the Torgashino deposit – new type of carbonate vein onyx (Krasnoyarsk territory)
Статья научная
A new type of carbonate vein onyx is identified. The onyx composition is calcite. Banding is preconditioned by alternation of the zones of light calcite, and calcite rich in ferruginized argillisite. Three types of vein bodies are composed of poorly dislocated, brecciated and concretion onyx. The latter type is presented by easily dissected concretions (5-12 cm). Calcite crystal fragments (1-3 cm) overgrown by concentric-zonal ferruginized much argillisite-altered calcite onyx looking like “rounded pebble” (2-4 cm) from outside, overgrown in its turn by concentrically banded large radial-columnar calcite crystals form the concretions. Concretions are interesting in terms of collection material.
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Conditions for conducting experimental studies on grain drying
Статья научная
This paper examines the effect of heater power, speed of drying agent (air), adjustable slit width and number of revolutions of drying drum on the drying efficiency of the device, the moisture content of the rice pile coming out of the drum, and the chatness of rice in the rice pile. In addition, showed the changes in the value of the heating power and the drying efficiency of the device. The change of the adjustable slot size of the drying drum and the drying efficiency of the device consist of determining the effect of the moisture content of the pile of rice coming out of the drum and the effect of rice chatnash in the pile of rice. The experimental rice drying device in a stationary version was prepared at the “Andijan experimental-testing plant” JSC according to the design drawings developed by the Andijan Institute of Mechanical Engineering. Based on the results of theoretical studies, a drying drum with a diameter of 880 mm and a length of 1800 mm was adopted as the main working body.
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Construction of geographic information system of corporate level in geological prospecting
Статья научная
The paper describes the experience of application of geographic information technologies and methods of processing of the Earth remote sensing data for solving practical tasks in the search for hydrocarbon deposits. The most important feature of technological processes in this sphere is the necessity to analyze large flows of spatially distributed data of different nature in real time. We propose a service-oriented approach to organize a geographic information system (GIS) in order to optimize the solution of tasks in nature management and exploration for oil and gas studies.
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Control of convective flows in liquid metal influenced by electromagnetic forces
Статья научная
During preparation of metal alloys stirring of the melt plays an important role in order to even its chemical composition and temperature in the whole bath volume. It is necessary to create specific convectional streams of metal in the bath for effective stirring. Based on the known analysis of selforganization of convectional streams in the liquid heated from beneath (Rayleigh-Bernard effect), the present article describes a MHD-stirrer which allows receive a similar pattern of streams in the molten melt by using electromagnetic force. We have considered stirring processes in the rectangular bath and a MHD-stirrer which allows increase efficiency and reduce energy costs on the alloy preparation process.
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Control of the shape of semiconductor crystals when growing in Czochralski method
Статья научная
A model of the formation temperature and the rate of withdrawal of semiconductor crystals when grown by the method of “Czochralski”, which allows you to control the shape of the crystals, providing a fl at solidifi cation front and getting a quality fi nished product.
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Cooperative spectrum sensing based on softened two-bit hard combination scheme
Статья научная
This paper measures the performance of cooperative spectrum sensing, over Rayleigh fading channel and additive white Gaussian noise, based on softened two-bit hard combination scheme. Two measures based on energy detection are considered including effect of false alarm probability, and effect of number of users. Simulation results show that the detection probability increases with the increase of false alarm probability, number of users, and signal-to-noise-ratio.
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Corrosive fluid effects on volute surface roughness in centrifugal pumps: a computational study
Статья научная
Corrosive fluids, namely, hydrogen peroxide (H2O2), hydrochloric acid (HCl) and sulfuric acid (H2SO4) can be used as a working fluid for volute surface roughness to study its impact on an existing H47 centrifugal pump. To analyse the effects of volute surface roughness, ANSYS student version 2023 software was used - wherein; head rise (H), pump speed (N), discharge rate (Q), inlet pressure and roughness height (h) of 20-40 m, 2000 rpm, 144 m3/h, 0 atm and 0.5 m, were respectively specified as initial and boundary conditions in the computational fluid dynamics (CFD) tool. CFD of volute roughness were respectively simulated for all corrosive fluids to obtain pressure and velocity distribution and profile plots of the analysis using fluid constant properties. The presence of volute wall roughness was observed to increase hydraulic losses in the volute when using corrosive fluids. The hydraulic loss in the volute due to wall roughness is influenced by the viscosity of the respective fluids. Denser fluids, like HCl and H2SO4 required more input power for the same flow rate, highlighting the viscosity-dependent nature of hydraulic losses. Smoothing and refining the volute wall may lead to a significant increase in pump performance without compromising impeller flow conditions. Exploring the effects of smoothing and roughening the volute wall on pump performance should be investigated.
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Статья научная
The analysis of the effect of systematic errors in pseudorange measurements on the accuracy of determination the coordinates in the plane of the horizon is presented. The criteria for selecting navigation satellites GLONASS are proposed to minimize the systematic components of the error of the planned coordinates, determined on the basis of the method of least squares. The results of checking the effect of selection of satellites when processing real pseudorange measurements by signals of the GLONASS system are presented.
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Статья научная
The article presents the results of the research of the cutting process of complex contour products from cellular honeycomb structures based on aluminum alloys, with a cutting tool in the form of a thin narrow blade with double-sided sharpening, reciprocating perpendicular to the wall of the honeycomb structure. The functional dependence of the cutting force and speed on the sharpening angle of the cutting tool blade and its thickness has been established. The optimal distance of the cut plane from the nodal points of the honeycomb structure is determined. The results of numerical simulation and experimental research to determine the optimal processing parameters that ensure the maximum cutting quality are presented. The reliability of the results obtained at the stage of analytical calculations and numerical simulation was confirmed experimentally by full-scale tests. As a result of the research, the optimal parameters and conditions of the cutting process were established: the thickness of the cutting tool is 0.4 mm, the sharpening angle is 20°, the speed of the tool is 5 m/s, the distance of the cut plane from the nodal point is 0.4 of the length of the cell wall. The results of the research can be used in the creation of a fundamentally new technological equipment for processing honeycomb cellular fillers, which have low manufacturability with traditional types of processing, which has found wide application in aviation and space production and makes it possible to produce complex-contour products from cellular honeycomb structures based on aluminum alloys. without additional processing, which increases its speed and reduces the cost.
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Cнижение оксидов азота в процессе сжигания Канско-Ачинских углей
Статья научная
Изучена возможность использования понятия эксергии для решения экологических проблем, связанных с совершенствованием процесса вихревого сжигания канско-ачинских углей с учетом снижения оксидов азота. Эксергия является единственным понятием в физике, определение которого включает в себя окружающую среду и особенности технической системы. Изложены мероприятия по снижению вредных выбросов с применением метода эксергии и аппарата неравновесной термодинамики для оценки их эффективности.
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Deep purification technogenic solutions of nickel ions (II) by the modified aluminosilicate
Статья научная
There studied an adsorption method for purifying technological solutions of nickel (II) ions modified aluminosilicates. The obtained adsorption isotherms. Experimental data were processed using the models of Langmuir, Freundlich, BET and Dubinin-Radushkevich. Defined constants for these equations. It is shown that the adsorption on aluminosilicates modified poly-1-vinylimidazole best describes the model of Freundlich the adsorption on aluminosilicates modified poly-4 vinylpyridine - Langmuir. The model of Dubinin-Radushkevich is used to calculate the free energy of adsorption. For all modified aluminosilicates, the value of free energy of adsorption, indicates an ion exchange mechanism, and fixation the ions of Nickel (II) has a chemical nature.
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Design of 2.4 GHz microwave bandpass filter
Статья научная
This paper presents in detail the design of highly selective microstrip bandpass filters that consist of microstrip open-loop resonators with a cross coupling that exhibit a single pair of attenuation poles at finite frequencies. The design approach enables one to use advanced full-wave EM simulators to complete the filter design, namely, to determine the physical dimensions of the filter. The results acquired through research & development process are simulated, analyzed and verified by using parallel-coupled lines filter topology, which are later, enhanced by various value-aided software tools such as MATLAB-7.0, CorelDraw-12, Microwave Office-2012.
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