Журнал Сибирского федерального университета. Серия: Техника и технологии @technologies-sfu
Статьи журнала - Журнал Сибирского федерального университета. Серия: Техника и технологии
Все статьи: 1471
An improved multi-objective BPSO-based method for radial distribution networks reconfiguration
Статья научная
The present paper will introduce an improved BPSO algorithm for radial distribution networks reconfiguration. In this regard PSO algorithm has extensively been used in many of the previous literatures; however, here a new method will be introduced in order to update swarm position which is not only simple and fast but also has high accuracy. The objective function has four weighted components representing load balancing, total losses of network, voltage deviation and system reliability. The test network is a standard distribution system with 3 feeder and 16 switches. Accuracy and speed of proposed method are compared with three other well-known algorithms to ensure its efficiency.
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Analysis of the Younger Dryas impact layer
Статья научная
We have uncovered a thin layer of magnetic grains and microspherules, carbon spherules, and glass-like carbon at nine sites across North America, a site in Belgium, and throughout the rims of 16 Carolina Bays. It is consistent with the ejecta layer from an impact event and has been dated to 12.9 ka BP coinciding with the onset of Younger Dryas (YD) cooling and widespread megafaunal extinctions in North America. At many locations the impact layer is directly below a black mat marking the sudden disappearance of the megafauna and Clovis people. The distribution pattern of the Younger Dryas boundary (YDB) ejecta layer is consistent with an impact near the Great Lakes that deposited terrestrial-like ejecta near the impact site and unusual, titanium-rich projectile-like ejecta further away. High water content associated with the ejecta, up to 28 at. % hydrogen (H), suggests the impact occurred over the Laurentide Ice Sheet. YDB microspherules and magnetic grains are highly enriched in TiO2. Magnetic grains from several sites are enriched in iridium (Ir), up to 117 ppb. The TiO2/FeO, K/Th, TiO2/Zr, Al2O3/FeO+MgO, CaO/Al2O3, REE/ chondrite, FeO/MnO ratios and SiO2, Na2O, K2O, Cr2O3, Ni, Co, U, Th and other trace element abundances are inconsistent with all terrestrial and extraterrestrial (ET) sources except for KREEP, a lunar igneous rock rich in potassium (K), rare-earth elements (REE), phosphorus (P), and other incompatible elements including U and Th. Normal Fe, Ti, and 238U/235U isotopic abundances were found in the magnetic grains, but 234U was enriched over equilibrium values by 50 % in Murray Springs and by 130 % in Belgium. 40K abundance is enriched by up to 100 % in YDB sediments and Clovis chert artifacts. Highly vesicular carbon spherules containing nanodiamonds, glass-like carbon, charcoal and soot found in large quantities in the YDB layer are consistent with an impact followed by intense burning. Four holes in the Great Lakes, some deeper than Death Valley, are proposed as possible craters produced by the airburst breakup of a loosely aggregated projectile.
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Статья научная
The article considers the modeling and analysis of transient processes in a system of substation Zarya500 kV with different external conditions during commutation shunt reactor ROMBS-60000/500. Revealed that the high-frequency overvoltageduring switching shunt reactor of 500 kV, can be dangerous for air insulation transformers TSZ-630/15.
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Статья научная
The article is devoted to the determination of the fractal dimension of the porous surface and further finding the relationship of the fractal dimension with the porosity of cellular concrete. A numerical experiment was carried out aimed at determining the fractal dimension of the structure of cellular concrete in order to clarify the relationship of the latter with its porous structure. An approach has been developed to assess the properties of cellular concrete based on the analysis of its image.
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Anodic behavior of Zn22Al alloy, doped with erbium
Статья научная
The article presents the results of a potentiodynamic study of the anodic behavior of the Zn22Al alloy with erbium dopants in various corrosive media of HCl, NaCl and NaOH electrolytes. Erbium alloying additions corrosion rate in various corrosive environments. In this case, there is a shift in the potentials in amounts of 0.01÷1.0 wt.% somewhat increase the anode resistance of the Zn22Al alloy by reducing the of corrosion, pitting formation and repassivation of alloys to the region of positive values. The dynamics of changes in electrochemical potentials favorably affects the parameters of the corrosion resistance of alloys. Erbium additions monotonically reduce the corrosion rate of the anode Zn22Al alloy in various media.
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Antenna arrays on surfaces of revolution
Статья научная
In this paper explicit analytical expressions are derived which describe radiation pattern of multi ring antenna array and multi ring continuous radiator allocated on an arbitrary surface of revolution. Radiation patterns of semi-spherical, conical and hyperbolical antenna arrays are shown.
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Application of UWB modem in WBAN network: performance study over AWGN channed
Статья научная
The major constraints in the design of Wireless Body Area Network(WBAN) can be attributed to the battery autonomy, need for high data rate services and low interference from the devices operating within the industrial, scientific and medical (ISM) bands. To meet the demand for high data rate services and low power spectral density to avoid ISM band interference, an ultra-wide band(UWB) system based technology has been proposed. This paper focuses on the design and demonstration of an UWB modem to be used in the WBAN applications and the evaluation of its performance in a near-real world scenarios affected by additive white Gaussian noise(AWGN) interference. The modem is tested with different values of signal to noise ratio(SNR). Results show that the performance of the modem degrades as the value of SNR decreases.
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Application of biological substances to increase the strength of materials and structures
Статья научная
This article explores the innovative field of bioconcrete, where bacteria, specifically Bacillus pasteurii, are employed to enhance the strength and durability of concrete structures. The key mechanism involves the bacteria’s ability to produce urease, catalyzing the hydrolysis of urea into carbonate and ammonia. The resulting carbonate ions react with calcium ions in the concrete, forming calcium carbonate (calcite), which fills cracks and pores in the structure. This process not only contributes to increased strength but also provides bioconcrete with remarkable self-healing properties.
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Application of error - correcting coding in hydroacoustic communication channels
Статья научная
The paper considers the possibility of using error-correcting coding in hydroacoustic communication channels (HACC).Comparison of test results shows that errors substantially packaged, resulting in increase of error probabilities with the large multiplicity and the likelihood of receiving a code word without error. Results of comparative statistical studies of these codes on a channel model with impulse hindranceare listed. As a result of theoretical and practical studies of various structures of error protection device (EPD) to improve the noise immunity of equipment sonar communication systems (HACC) was selected the algorithm of error correction, which is based on convolutional code R = 1/2 with block, the threshold, the iterative decoding. To ensure the independence of errors at the decoder input (decorrelation of error stream), the matrix interleaver are encouraged to use in the EPD.
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Application of fluxes for melting and processing of aluminum alloys
Статья научная
This article explores of the effect of the composition of the protective flux on the melting process of aluminum alloys and their mechanical properties. Experimental studies have been carried out with various flux compositions in order to optimize the melting process and improve the quality of the alloys obtained. The results showed that the change in the composition of the flux has a significant effect on the structure of the alloy and its mechanical characteristics. Optimization of the flux composition can lead to improved strength, corrosion resistance and other important properties of the alloy. The results obtained can be used in the metallurgical industry to optimize the melting process of aluminum alloys and improve the quality of products.
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Application of methods combined treatment for obtaining welding wire from silumins
Статья научная
Developed technology of obtaining rods and wires from silumins using casting in electromagnetic crystallizer and follow combined rolling-extruding and drawing. Were carried studies of properties of deformed semi-finished products and obtained experimental batches of welding wire from alloys AlSi5 and AlSi12.
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Application of modified sorption material for efficient wastewater treatment of galvanic production
Статья научная
The galvanic production is one of the source of environmental contamination by harmful substances and especially heavy metals. The questions of water pollution prevention by wastewater containing heavy metal ions, are closely linked to the development of event to reduce fresh water consumption for technological needs of production and to reduce the amount of wastewater. One solution to this problem is the creation of low-waste and waste-free environmentally safe production processes of sewage treatment with the use of treated wastewater in the working cycle, which leads to a reduction of negative impacts on the environment.
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Статья научная
Entropy criteria of traction substations of 110-220 kV schemes’ unreliability are considered in this article in the conditions of indeterminacy of schemes’ conditions. It is shown how the application of entropy estimates during scheduling reconstruction of traction substations allows to estimate effectiveness of measuring to increase non-failure operation and substations’ schemes electrical connections availability.
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Статья научная
The article considers the application of two approaches to optimizing the direct-flow burners and nozzles location using numerical simulation. The study objects are two furnaces of the traditional and invert type with solid slag removal for boilers for supercritical and ultra- supercritical steam parameters, respectively. The lean hard Kuznetsk coal was used for both cases, somewhat different in characteristics in the cases under consideration. This coal type is currently burned mainly in furnaces with liquid slag removal. The use of the zone-by-zone optimization method implies a sequential each pre-selected zones optimization of the furnace in the direction of flue gas movement with modeling of the solid fuel combustion process with different burner and nozzle layouts. A dimensionless scheme for burning coal dust in a traditional furnace with an upward flue gases movement has been developed. The use of a simplified numerical model (SNM) due to certain settings made it possible to approximate the results of furnace aerodynamics modeling without taking into account the chemical reactions to the results with combustion simulation, which significantly reduced the conducting research time. As a result of modeling the invert furnace aerodynamics, the optimal arrangement of direct-flow burners and nozzles was selected. The article discusses the main features of each research method use, optimization criteria, research objects, initial combustion schemes, design parameters of combustion schemes that are changed during optimization, as well as the main results of the optimization. The solid fuel combustion schemes obtained using two approaches to conducting research using direct-flow burners and nozzles ensure the operation of the considered furnaces with better values of efficiency and environmental indicators than traditional combustion of similar fuel in furnaces with liquid slag removal. The obtained values are at a level acceptable for the Russian Federation.
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Application of «gradient» algorithm to modeling thermal pipeline networks with pumping stations
Статья научная
The paper deals with the analysis of flow distribution in regulated pipeline systems. Proposed inclusion of nodal elevations and piezometric heads into «global gradient» system of equations allows estimation of hydraulic regimes of thermal networks with pump stations, flow- and pressure-control valves during the process of iterative approach. Application of proposed modification of the Todini’s GGA method to calculation of flow distribution is shown on example of a small thermal network with pumps.
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Approaches to nordifikation of high-latitude construction engineering
Статья научная
The simple mechanical transfer of structural technologies to high-latitude construction engineering is not efficient. But construction engineering nordifikation seems to be effective and expedient, for example working camps. Severe, extreme conditions in the Arctic are similar to extraterrestrial, for example, Martian therefore use of space technologies is required here. From this point of view, it is expedient to build space frame constructions such as: domes, lenses, spheres, Rello’s cones united by the covered transitions of ribbed type or the common covering, having good aerodynamics. In this article is emphasized the rationality of designs made of timber itself and wood materials that defines need of creation of the glued elements industry, that is possible only in presence of government support.
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Approaches to simulation of interaction of concentrated solar radiation with materials
Статья научная
The paper analyzes approaches to modeling the processes of interaction of concentrated solar radiation with materials. The experimental results obtained on the synthesis of materials from a melt in a solar furnace are presented. It is shown that when melting in a solar furnace under the influence of concentrated solar radiation of high density due to the acceleration of the recovery process, it is possible to obtain a fine-grained microstructure that gives the material enhanced mechanical and dielectric properties. It is shown that the relationship between the structure and properties of the materials obtained with the technological parameters of melting and cooling in a solar furnace can be used as an approach to modeling the interaction of concentrated solar radiation with materials.
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Статья научная
The architecture and the main characteristics of an information system are presented in article, they allow to solve a complex of the problems connected with estimation of a condition of agricultural lands on the basis of processing of spatial data. The system is based on the ontology of estimation of agroeconomic capacity of lands developed by authors.
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Статья научная
For crystals grown from the liquid melt using the Czochralski method, the mathematical model of the current control chip area by controlling the conditions of the contact sensor circuit level of the melt in the crucible, which allows to calculate the control signal, as the difference between the current and the target area grown crystals.
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Assessment of agroecosystem productivity based on satellite data and a mathematical model
Статья научная
The possibility of determining seasonal dynamics of agroecosystem productivity was estimated based on the combined use of satellite data and results of a mathematical model study. The study showed a qualitative agreement between normalized difference vegetation index (NDVI) and the total aboveground phytomass of the wheat and oat agroecosystem. Analysis of the mathematical model proved the possibility of prediction and improvement of the crop yield estimate. A distinction has been made between the vegetative and reproductive biomass of the agroecosystem. Results of mathematical modeling were in good agreement with ground-truth data in the case of nutrient (nitrogen) limitation.
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