Исследования. Проектирование. Опыт эксплуатации. Рубрика в журнале - Журнал Сибирского федерального университета. Серия: Техника и технологии
Methods for preventing ferrocene catalyst migration into solid fuels
Статья научная
Ferrocene compounds are among the most common solid fuel combustion speed catalysts, which have attracted the attention of scientists due to better combustion speed, ease of production, purity percentage and high efficiency. Due to their high migration, the main problem of these compounds is their migration during storage, which can reduce engine performance and cause subsequent risks. Various methods have been proposed to solve this problem, including branching, adding active groups and creating bulky compounds or strengthening intermolecular bonds, polymerization, excessive branching, etc., due to the high importance of the migration phenomenon. In the exploitation of solid fuels, this article introduces ferrocene-based combustion rate catalysts and briefly reviews methods to prevent their migration.
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Mutual coupling enhancement in antenna array
Статья научная
Antenna arrays are very important in wireless communication networks, as they can sustain radiation direction change, with high capacity and high gain requirement. Mutual Coupling (MC) between antenna arrays has effects on some parameters, impedance, reflection coefficients, radar cross-section, and array performance. Most significantly, the MC has greatly influenced the efficiency of the antenna array. This phenomenon reduces array signal processing efficiency. To address this constraint, different approaches have been proposed in this article. The usefulness of multiple approaches lies to a major degree in implementations in which the arrays have been applied. This article is a comprehensive study for investigating MC influences on several parameters, including impedance and radiation pattern. In addition, some developed decoupling methods are outlined, receiving the Mutual Impedance Method and S-Parameter Process, including the open-circuit voltage mechanism. This can aid in contrasting the different strategies in order to allocate enough knowledge to help future research.
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On the choice of some modifiers when creating composite nickel-phosphorus coatings
Статья научная
The article considers the issues of choosing some modifiers of composite nickel-phosphorus coatings (CNiPC) using the method of crystal-chemical design in order to create high reliability and durability in the friction units of machines and mechanisms of tribological systems (TS). The paper shows the possibility of improving the tribological and anti-corrosion properties of NiP coatings without modifiers by introducing modifying additives into the coatings - ultradisperse powders of simple and complex metal oxides, oxides with corundum and rutile structures, simple substances with magnesium and tungsten structures, and polytetrafluoroethylene.
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Статья научная
The article considers the problem of insufficient use of solar potential in the southern regions of the Republic of Tajikistan, where limited access to centralised energy supply negatively affects the quality of life of the population. The main objective of the study is to analyse the performance of autonomous solar power plants for these remote regions with a focus on assessing the impact of climatic factors and equipment parameters on the efficiency of electricity generation. The methodological basis of the study includes modelling the operation of solar energy systems using the PVsyst software package. The software modelling allows taking into account key parameters such as solar radiation level, PV panel tilt angle, shading and temperature fluctuations. Based on the analysis of load data and daily electricity consumption, the parameters of PV modules, batteries and controllers were determined and optimised. The simulation results showed that with an installed system capacity of 13.68 kW, the energy demand coverage ratio reaches 100 % and the system efficiency is 13.57 %. Graphical and tabular data show the monthly distribution of generation and energy losses due to the climatic peculiarities of the region and the technical characteristics of the system. The conclusions of the study emphasise the need to select quality equipment and optimise design parameters to ensure high efficiency of autonomous solar power plants in conditions of remoteness from centralised power grids and significant solar resources. In addition, the obtained results can serve as a basis for the development of effective recommendations for the design and implementation of solar energy systems in the southern regions of Tajikistan, which will contribute to the improvement of energy security and sustainability of energy supply in these territories.
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Статья научная
Photovoltaic-thermal (PVT) panels combine solar thermal and photovoltaic technologies and generate simultaneously both heat and electricity. They can be a good variant for small domestic households to reduce their energy costs. This paper looks at the potential of these systems into the climates of Vladivostok, Russia, and Tehran, Iran. In the article, some brief background information on PVT systems and the concept of prosumers is introduced. Next, a similar PVT system is proposed for a given household consumer in Vladivostok and Tehran with the variable weather conditions corresponding to the two locations. The PVT system is modeled in TRNSYS (v18, Thermal Energy System Specialists, Madison, USA). A performance analysis is carried out in order to establish the daily instantaneous energy output and the annual energy production. The results indicate a 15-20 % better performance in Tehran compared to Vladivostok due to slightly better weather conditions, though the total efficiency of system has a better performance in Vladivostok. The system efficiency was assessed through two different methods. This study concludes that both the Russian and Iranian PVT market has a good potential for adopting the technology, especially since it is currently less mature than other leader countries in renewable energies.
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Potential bases of physical modification of local minerals-heterocomposite polymer materials
Статья научная
The article explains that “Angren Kaolin” LLC produces enriched kaolin of AKF-78, AKS-30, AKT-10 brands, Kaolin AKF-78, mainly used as a filler in paper production and its unique properties include excellent adhesion and a high kaolin particle thickness ratio of 30:1 and solar curing of the polymer composition to control the strength response in the preparation of highly viscous epoxy composites using GS in a 10:10 (w/w) ratio with DBF, high-viscosity epoxy compositions using gossypol resin in a ratio of 50:50 with DBP, which is an effective way to save energy, and solar treatment of the polymer composition is important in their practical application in the industry for technological equipment and products operating under conditions of corrosion-hydroabrasive corrosion save energy in cooking, effective way to control the hardening reaction.
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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.
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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.
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Study on long-term tempering on the microstructure of creep strength enhanced ferritic P92 steel
Статья научная
Present paper deal with the studies of effect of long term heating on the microstructure and mechanical properties of creep strength enhanced Cr-Mo P92 steel. Such steels are used in supercritical power plant boilers where continuous operating temperature and pressure can be as high as 650 0C and 300 bar respectively. The P92 specimens were thermally exposed at temperature of 650 0C for duration of varying from 1000 to 3000 hours. Tensile fracture and impact toughness fracture surfaces were studied by using scanning electron microscope. The fracture surface of P92 impact toughness specimen exhibited both inter lath-decohesion and ductile dimple tearing. The various phases that formed in the tempered P92 steel were analyzed by X-ray diffraction. In XRD analysis of tempered P92 it was observed that amount of precipitates increased as compared to untemperedcondition. After tempering time of 1440 h, some new precipitates such as NbC, NbCrN were also observed.
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Supercapacitor as a buffer electrical source for induction motor
Статья научная
Mathematical substitutions in the equations and the used methods have shown the adequacy and correctness of their use. Analysis of the data, obtained from simulation modeling of the developed model, showed small discrepancies with the standard block from the Simulink library. The use of the obtained mathematical equations, as well as the model assembled in Matlab Simulink, will make it possible to qualitatively evaluate the operation of an induction drive in statics and dynamics. This model will be used in future research, including the creation of a buffer power source based on a supercapacitor for an induction electric drive.
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Статья научная
In this paper, we analyzed the vehicle’s driving modes and opted for the idle mode to save fuel. The synergy of the vehicle with the traffic light depends on many factors and has been studied on the example of the information model of the “Intelligent start-stop system”. A vehicle with an “intelligent start-stop system” was saved 8.25 % of fuel during 100 km in urban conditions. In addition, emissions of harmful gases into the environment have been minimized. It was found that an average of 132 liters of fuel was saved when one vehicle traveled 20,000 km per year. Moreover, the idling time of the vehicle’s engine was characterized by a reduction of 28-32 % in 100 km of the total test distance. Also included are the concepts of order parameter and flexible parameter on the principles of synergetic by using intelligent transport systems in the local condition.
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Synthetic fuel production: thermal behavior of lemon and orange peels composite fuel diesel
Статья научная
This study aimed to investigate the thermal combustion behavior of lemon peel powder, LPP and orange peel powder, OPP composite fuel diesel. The pyrolysis experiments of the diesel/ citrus composite fuel were conducted in combustion chamber. The results showed that the citrus/diesel composite fuel sustains its combustion properties at 30 % of the added citrus peels powder,. The results showed that calorific values of diesel containing 30 % LPP or 15 % LPP + 15 % OPP were very close to that of the pure diesel. The maximum calorific values were obtained at α = 0.85, 0.80 and 0.90 for 30 % OPP, 30 % LPP and 15 % OPP + 15 % LPP composite fuels respectively.
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The Influence Manganese on the Kinetics of Oxidation of the Zn5Al and Zn22Al Alloys
Статья научная
The article presents the results of thermogravimetric studies on the influence of alloying additions of manganese on the oxidation kinetics of zinc-aluminium alloys Zn5Al and Zn22Al. The values of the true oxidation rate of the zinc-aluminium alloys Zn5Al and Zn22Al, alloyed with manganese, calculated from the kinetic curves, are given as a function of temperature and the composition of the studied alloys. It is observed that small additions of manganese (0.01–0.05 wt.%) significantly reduce the true oxidation rate of the zinc-aluminium alloys Zn5Al and Zn22Al, while simultaneously increasing the apparent activation energy of this process. Larger additions of manganese (0.1 and 0.5 wt.%) also reduce the oxidability of the base alloy.
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The influence of thallium additives on the kinetics of oxidation of the Zn22Al alloy
Статья научная
The article presents the results of a thermogravimetrical study of the effect of thallium alloying additives on the oxidation kinetics of the Zn22Al alloy. Established in the temperature range of 473-623 K the kinetic and energy parameters of the oxidation of alloys. The oxidation of alloys proceeds according to the hyperbolic mechanism and has the order of 10-4 kg∙m-2∙sec-1. Higher activation energies indicate that the oxidation of these alloy samples results in the formation of oxide films with good protective properties. Additives of thallium in amounts of 0.01-1.0 wt.% contribute to a decrease in the oxidizability of the Zn22Al alloy. The resulting products during the oxidation of the studied alloys consist of a mixture of oxides ZnO, ZnAl2O4, Al2O3, Tl2O3.
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Thin magnetic film magnetometer
Статья научная
This paper presents a novel design of a dual resonator broadband sensor for weak magnetic fields based on thin magnetic films. Such sensors are widely used in various fields, e.g. in geological exploration. The magnetic field of the feedback coil in the sensor is orthogonal to the plane of the printed circuit board with the microwave oscillator. This makes it possible to extend the frequency bandwidth of the measured magnetic fields in the sensors based on thin magnetic films. This is achieved by reducing the effect of the electromagnetic shielding covering the microwave oscillator in the device.
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To the Issue of Application of Unstabilized Voltage in the Power Supply System of Spacecraft
Статья научная
In this article the spacecraft load voltage stabilization range influence on the specific power parameters (W/kg) of the power system as a complex of the electric power supply system and the secondary power supply devices (DC-DC convertors) built in loads is considered. It is showed that the secondary power supply devices usage in the on-board equipment on the base of a flyback impulse convertor for the load voltage of (25–27) V allows providing for the higher specific parameters than for the load voltage of (17–36) V within the range of loads up to 3 kW. The graphic characteristics and analytic formulae are derived.
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Статья научная
At present, the process of converting potential energy concentrated in the surrounding air is of considerable interest when using its active component. For many years, searches have been made for ways to increase the efficiency of existing energy sources, the continued study of which would not lead to environmental consequences for mankind. Much attention of scientists is attracted by the problems of energy inversion. And the most acute issue is the control of energy inversion, which is a single process of energy transformation from one state to another, occurring simultaneously in the “concentration-dispersion” format in the surrounding air. This kind of opportunity to use ambient air as renewable energy sources is provided by air heat pump systems, the heat supply of which is practically the only effective, environmentally friendly source of heat supply in buildings at present. However, modern air heat pump systems cannot be attributed to systems operating only on renewable energy sources, since their operation requires, according to the technology, a certain amount of electrical energy to start the compressor engine, which ensures the operation of a closed compression cycle of the evaporative-condensation unit. At present, it is not possible to achieve a full autonomous mode of operation of an air heat pump system without the use of an additional energy source. Continuing the innovative and effective way of developing the extraction of the surrounding air for the purpose of obtaining thermal and electrical energy, scientists propose to use the capabilities of modern quantum wave technology, based on thermodynamics and electrodynamics. To solve this problem, they followed the path of development of modern electronics, realizing that electrons - “quanta” determine the vast majority of the physical and chemical properties of the bodies around us. Such a process of heat and mass transfer, in the conditions of the surrounding air, under the influence of external forces of the energy field, is the environment in which natural and artificial electric currents propagate.
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Статья научная
The study reports results of analyzing the dynamics of forest vegetation phenology associated with climate change in Siberia (the Stolby National Park, Krasnoyarsk Krai). Correlations between the start of growing season (SOS) and land surface temperature (LST) in March, April, May, and June and between the end of growing season (EOS) and LST in August and September have been analyzed. Regions where the growing season of forest vegetation tends to increase have been revealed. The study shows that the longer growing season of forest vegetation is associated with the earlier start of the season, which is correlated with the rise in April air temperature. The later end of growing season of forest vegetation is determined by higher temperatures in both August and September
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Статья научная
Для эффективного решения задач по вскрытию подводной обстановки и обнаружению подводных объектов необходимы совершенные гидроакустические системы. Их создание должно не только основываться на «грубом» увеличении чувствительности приемных элементов и совершенствовании их конструкции, но и носить комплексный характер, основанный на научно обоснованном подходе. Предложен вариант подхода к построению гидроакустической системы (ГАС) с критерием минимума потерь и адекватного отображения подводной обстановки. Применен метод дискретизация зоны обнаружения и вычисление оптимального размера дискрета. На базе данного подхода разработана структура агрегирования варианта ГАС и ее элементы, содержание базы исходных данных, предъявляемые требования к модулю формирования контура требований к ГАС, решаемые задачи модулем формирования вариантов ГАС и необходимые для этого данные.
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Адаптивная регулировка спектральной составляющей мощности излучения многоволновой лазерной системы
Статья научная
В данной статье представлен способ повышения энергетической эффективности систем, использующих для передачи информации лазерное излучение, путем автоматического выбора рациональной мощности излучения. Разработана модель процесса адаптивной регулировки спектральной составляющей мощности излучения многоволновой лазерной системы на основе анализа величины отраженного от ретрорефлектора оптического сигнала в интересах обеспечения требуемого уровня мощности лазерного излучения для надежной передачи информации каждым отдельно взятым каналом. В программной среде MATLAB Simulink, на основе математического аппарата теории автоматического управления, произведена имитация исследуемого процесса и подтверждена адекватность предложенной модели. Модель подразумевает возможность ее коррекции путем изменения усиливающих и инерционных свойств элементов схемы для описания частных случаев функционирования многоволновой лазерной системы.
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