Журнал Сибирского федерального университета. Серия: Техника и технологии @technologies-sfu
Статьи журнала - Журнал Сибирского федерального университета. Серия: Техника и технологии
Все статьи: 1579
Reliability evaluation method of the wind-diesel installation with application of dynamic fault tree
Статья научная
Renewable energy sources becoming more widespread in decentralized power supply systems. However their functioning depends on the natural resources potential having variable character. This dependence influences reliable work of autonomous power supply system. Reliability analysis of a renewable energy based autonomous generating system is the actual practical task requiring the solution. For the reliability assessment of autonomous wind-diesel installation it is offered to use the method of dynamic fault tree with Markov models for representation of dynamic operators. The offered method is applied for reliability calculation of the wind-diesel installation functioning in the autonomous power supply system in the north of Krasnoyarsk region.
Бесплатно
Статья научная
This article represent the results of research of mechanical and electrical properties of deformed semi-fifnished products from alloys system Al-Zr, obtained with using methods of combined casting-rolling, combined casting and rolling-extruding and drawing.
Бесплатно
Статья научная
This article examines the issues of hydraulic resistance of solar air heaters with concave tubes and reduction of pressure losses, as well as the determination of the air flow in concave tubes installed in the working chamber of the solar air heater and discusses the reduction of the number of common tubes to reduce pressure losses in the solar air heater and the installation of concave pipes to give air a swirling motion to eliminate a sharp decrease in the heat transfer process.
Бесплатно
Researching the Energy Balance of Swimming Pools
Статья научная
Swimming pools are among the buildings that consume the most energy, and it is important to reduce their energy consumption by widely introducing energy devices based on renewable energy sources into the pool heating system. In our republic the analysis of renewable energy resources and the use of renewable energy sources in the electricity and heat supply of swimming pools is economically profitable too. This article analyzes the energy balance of swimming pools and the possibilities of using renewable energy sources in their heating.
Бесплатно
Retraining data sequence for combined detector
Статья научная
This work presents two detectors that are employed to manage the intersymbol interference that the communication channels introduce. These two detectors work by combining a Viterbi detector and a nonlinear equalizer. The second detector, which this study contributes, is called Combined Detector-2(CDR2). The first detector, which was previously constructed, is known as Combined Detector-1(CDR1). With a different data sequence, CDR2 is comparable to CDR1. Data transfer at 9.6 kbps over telephone channel is used to test these detectors with a nonlinear equalization. According to simulation data, the CDR2 performs better than the CDR1, whereas the nonlinear equalizer performs better than the CDR1.
Бесплатно
Review on ADPCM System and its Applications: US Patents from 2024 to 2025
Статья научная
The Adaptive Differential Pulse Code Modulation (ADPCM) has been standardized by the International Telecommunication Union (ITU) due to its significance and extensive applications within telecommunication networks. This paper provides a concise overview of the recent US patents related to ADPCM, covering the years 2024 to 2025. Additionally, the general architecture of ADPCM is discussed. The findings presented herein aim to inspire researchers and motivate further explorations in this domain.
Бесплатно
Satellite Monitoring of Atmospheric Carbon Dioxide in Krasnoyarsk Krai
Статья научная
The present study analyzes the year-to-year (2003–2021) and seasonal variations in concentration of atmospheric CO2, Land Surface Temperature (LST), and Normalized Difference Vegetation Index (NDVI) in Krasnoyarsk Krai, based on satellite data. Over the study period, the annual average concentration of atmospheric CO2 had increased by 41 ppm. Analysis of seasonal variations in CO2 concentration demonstrated a carbon dioxide decrease in summer and an increase in winter. Positive trends were revealed in the annual average LST and the average NDVI values for a period between March and October in Krasnoyarsk Krai over 2001–2023. Analysis of the spatial distribution of CO2 in the atmosphere of Krasnoyarsk Krai in 2021 revealed higher CO2 concentrations (about 415 ppm) in the west of Krasnoyarsk Krai, as far as the Yenisei River. Lower CO2 concentrations (about 414 ppm) were found in the northern, island areas (ice-covered area and Arctic deserts) and in the regions of the Central Siberian Plateau and Sayan Mountains. Analysis of correlation of the LST and NDVI spatial distributions for 2021 revealed a positive relationship of NDVI to LST. In the northernmost, island part of Krasnoyarsk Krai, the negative LST value is correlated with the negative NDVI value. Farther south, a classical increase in LST and NDVI occurs. The coefficient of correlation between LST and NDVI over the entire area of Krasnoyarsk Krai is rather high: 0.83.
Бесплатно
Статья научная
Satellite-to-ground optical communication link bit error rate (BER) depending on atmospheric propagation, pointing errors is considered. The theoretical and numerical estimations of BER for GEO to Earth link under various conditions are proposed.
Бесплатно
Satellite monitoring of grain crops in the south part of Western Siberia
Статья научная
In agriculture an important issue is to obtain reliable information on the status of agricultural land. The article presents the most recent results of grain crops’ status monitoring based on remote sensing data on the example of the south part of Western Siberia.
Бесплатно
Satellite monitoring system for the Krasnoyarsk territory area based on small satellites use
Статья научная
The satellite monitoring system for the Krasnoyarsk Territory area is proposed. The main feature of proposed system is its implementation at three levels: space, low altitude and ground levels. Each level assumes the use of data compatible spectrophotometric equipment for subsequent integrated interpretation. The development of ground system for control, data acquisition, processing and distribution is assumed.
Бесплатно
Search for the new form of raw material for the alyumineevoy industry of siberiaode
Статья научная
This article presents the results of research into rational schemes ore enrichment Bazybajsk deposit (Krasnoyarsk region). Optimal conditions for sillimanit and quartz concentrates.
Бесплатно
Статья научная
The actual problem of duly revealing of mechanical stressed sections of fiber optical communication lines, in particular, optical fibers which are under influence of the raised mechanical pressure (strain) in optical cables is considered in this paper. Results of modeling of Brillouin backscattering spectrum changes depending on change of optical fiber strain are presented. Results of experimental examinations of strain characteristics of various types optical fibers, which are under longitudinal and transverse mechanical influences, based on Brillouin backscattering spectrum analysis are given in this paper. Also are discussed temperature dependences of Brillouin backscattering spectrum changes of the optical fibers. The received results confirmed a possibility to detect problem (mechanical stressed) sections and estimations of the optical fiber strain degree on basis of Brillouin refl ectometry method at different mechanical infl uences.
Бесплатно
Shok-free dismounting of cathode assembly lining of aluminum cells
Статья научная
The technology of dismantle of the cathodic device of electrolytic furnaces is considered. Lining destruction in the cathodic device of an electrolytic furnace is made by a special hydraulic press. In a lining material locally non-uniform loadings causing occurrence of cracks are created. The technology allows to exclude with great dispatch-vibrating influence on near electrolytic furnaces and to increase term of their operation.
Бесплатно
Short distance data transmission method by using QR code
Статья научная
QR code (quick response code) has become a widely common technology along with the increase in the usage of smartphone. In many areas, QR codes have over taken the place of linear barcodes due to the obvious advantages of large data capacity and ease of data retrieval. In this paper, we propose a novel data transfer scheme that employs the camera in smartphone devices as an alternative data channel. The sender device encodes data as a series of QR code images like the video data type. The video will be exhibited on the screen of smartphones, tablets, or PCs. The receiver device records the video by camera, splits video into frames, and decodes the data from images. This method is implemented by using multiple versions of QR code started from 1 to 40. By conducting several experiments, the version 19 is the best choice for transferring data between smartphone devices because of it’s the ability to transfer 135 Kbit/s without error. To transmit data from tablets and PCs to smartphone devices, the best version of QR code is 29, which allows 277 Kbit/s to be transferred without error. Further, the proposed method shows the advantages of permitting satellite TV channels to transfer files to viewers instead of giving file links. This results in solving the problem of transferring files from IOS and Mac devices to windows and android devices and vice versa.
Бесплатно
Siberian centre of Russian satellite designing
Статья научная
Space technologies are not luxury, but essential requirement for economic and social development of the country and guarantor of national security. In the Krasnoyarsk region, along with major extractive industries successfully operates a high-tech enterprise in space design Joint - Stock Company Academician M.F. Reshetnev developing space technologies and ensuring economic growth of Russia.
Бесплатно
Sigmaflow как инструмент исследования ветрового комфорта в условиях городской среды
Статья научная
Интенсивный рост современных городов приводит к строительству жилых микрорайонов с плотным расположением зданий различной высотности. Подобные архитектурные решения способствуют непредсказуемому изменению аэрационного режима территории, который может вызывать ухудшение экологической обстановки города, а также формирование дискомфортных условий в зоне пребывания человека. Для изучения механизмов формирования данных условий и прогнозирования ветрового режима используется микромасштабная модель атмосферы города, реализованная в программе «SigmaFlow». В работе представлены результаты верификации численной модели с экспериментальными данными на двух тестовых задачах обтекания модельных элементов городской застройки. Полученные результаты расчетов демонстрируют достаточно хорошее совпадение с экспериментальными данными. Кроме этого, был выполнен анализ формирования ветровых условий в реальном жилом микрорайоне. Получены характерные структуры течения при обтекании зданий, а также выявлены места формирования дискомфортных и опасных зон для пребывания человека.
Бесплатно
Simulation and calculation of heat transfer in multilayer wall structures based on iterative models
Статья научная
Through heat transfer is considered: heat carrier, liquid medium 1 - wall of arbitrary n layers - liquid external medium 2, cooler. For heat flows, a system of (n + 1) nonlinear equations is considered. The method of excluding unknowns sequentially calculates all values of tw, i. The design scheme allows iterative calculations of wall temperature from one to three layers and, accordingly, five heat flows. The novelty of the solution is that the temperature of the first wall tw,1 and the last wall tw, n+1 are not set, but are unknown. They are calculated using an iterative scheme.If you further increase the number of wall layers, the calculations become cumbersome. We are talking about the explicit expression of all tw, i through formulas based on the manual transformation of equations. Optimally bringing the problem to a closed and defined system (n + 1) of equations for (n + 1) unknown wall temperatures tw, i. This system of equations is easily calculated in mass accessible packets, to which Matlab belongs. The advantage is a matrix solution of the entire system at once. In the case of a system of cylindrical and spherical walls, the problem is also solvable. New coefficients have been established for these systems of equations. Which allows you to save balance equations for heat flows.
Бесплатно
Simulation modeling accounting for reservoir fluid properties heterogeneity
Статья научная
Current article deals with fluid properties heterogeneity. The reasons of this phenomenon are analyzed. 3D digital modeling of formation, saturated with oil having variable properties (density and viscosity) is performed. It is compared with model, built in the frameworks of classic approach, where oil has constant density and viscosity. It is shown, that accounting for oil properties heterogeneity allows making oil field design and planning of different activities more precisely.
Бесплатно
Simulation of a continuous ingots structure formation process
Статья научная
The presented results demonstrate the possibility of mathematical complex model in research of the temperature characteristics pattern changes in polymorphic transformations, isotherms of liquidus and solidus, and other parameters depending on the cooling conditions of the ingot. Shown the possibility of predicting parameters of a continuous ingot microstructure (distance between dendrites, size of the austenite and ferrite grains). Were made microstructure parameter calculations of the continuous steel ignot containing 0.17 % C, 0.62 % Si, 1.4 % Mn at various secondary cooling modes.
Бесплатно
Статья научная
Under study was the reaction of the basic operating performance of the cold low-shrinkage ramming paste (CRP) on the pre-heating conditions of the rammed joint. It was found out that the uncontrolled high-rate heat-up of the cold ramming paste (CRP) loosens the macrostructure and intensifies impregnation of the rammed layer. The controlled delayed rate in the temperature rise of the inter-block joint up to 400 °С enables to obtain a high-quality layer of paste with the improved barrier properties against its impregnation with electrolyte.
Бесплатно
