Исследования. Проектирование. Опыт эксплуатации. Рубрика в журнале - Журнал Сибирского федерального университета. Серия: Техника и технологии
Abnormal phenomena in the tropical part of the world ocean according to MODIS-Aqua satellite data
Статья научная
The work analyzes monthly data from the MODIS-Aqua satellite scanner on the temperature of the surface layer of water with a resolution of 4320×2160 (9 km at the equator) for 2002-2021, obtained from the Ocean Color Data website (https://oceandata.sci.gsfc.nasa.gov/MODIS-Aqua/Mapped/ Monthly/9km/). It was shown that the degree of influence of changes in ocean surface temperature on the atmosphere depends not only on the absolute values of temperature changes, but also on the surface area on which these changes occur. It was revealed that starting from the end of 2009 - beginning of 2010, the climate system of the tropical zone was destabilized, and reliably positive temperature trends began to prevail over most of the ocean surface in the tropics. At the same time, in the circulation belts of temperate latitudes, processes occur that are not synchronous either with the processes in the tropics or with each other. It was noted that zones with predominant warming or cooling are sometimes located nearby on the scale of the World Ocean, practically not separated by buffer zones. This could destabilize the ocean-atmosphere system. It was revealed that the predominance of warming processes in the Gulf Stream does not lead to a corresponding predominance of warming processes in the North Atlantic Current. The opposite is observed.
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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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Статья научная
Using data from the MODIS-Aqua satellite scanner, seasonal changes in ocean surface temperature (OST) in the Atlantic Ocean for the period 2003-2019 were studied. Based on these data, quasi-stationary zones were calculated based on the average monthly ocean surface temperature using the moving window variance method. Zones were identified that are quasi-stationary in terms of the seasonal dynamics of OST and that correspond to the present position of current boundaries. Significant differences in ocean surface temperatures were revealed. Areas in the ocean were identified that differ in absolute OST values, but have similar seasonal dynamics, as well as areas with different seasonal OST dynamics. An interesting fact has been revealed when currents that geographically continue each other do not always coincide in seasonal dynamics. For example, at the boundary of the North Atlantic Current and the Gulf Stream, there is a vast zone with no stable seasonal dynamics. The possibility of using this method for monitoring of mixing zones that arise at the boundaries of currents was shown.
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Cleaning of industrial emissions from gas and dispersive particles
Статья научная
This article presents the results of experimental and theoretical studies of the effective purification of dispersed-ring two-flow industrial gases from gaseous and dispersed particles, hydrodynamics and mass transfer. The devices are designed to reduce the harmful emissions of the established threshold permissible (ChRET) at relatively low energy costs.
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Cleaning of natural gases from sour components
Статья научная
The article presents absorption, adsorption, catalytic and membrane methods of purification of hydrocarbon gases from acidic components, as well as the technology of membrane purification methods.
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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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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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Design of pulse width modulation based dc motor for electric vehicle
Статья научная
The aim of this paper is to design and implement a power controller based on a microcontroller to be used in controlling a DC motor driving an electric vehicle. The ease of control and excellent performance of the DC motors ensure that it is widely used in many applications. This paper is mainly concerned on DC motor speed control system by using microcontroller PIC16F877A. Pulse Width Modulation (PWM) technique is used where its signal is generated in microcontroller. The program for PWM generation is written in C Language using MIKROC software. It is programmed into the microcontroller using Pickit 2. Then the microcontroller is installed into the motor control circuit. The Microcontroller acts as the motor speed controller in this paper. Based on the result, the readings are quite reliable. Through the paper, it can be concluded that microcontroller PIC16F877A can control motor speed at desired speed efficiently by using PWM signal.
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Determining properties of a flow-through supercavitation desalination plant
Статья научная
Nowadays humanity faces an increasing problem of fresh water, the resource of which is rapidly declining because of anthropogenic activity. In this regard, the development of methods and means of purification of natural waters from various impurities, both solid and gaseous, becomes a priority. Steam extraction from the supercavitation cavity for its subsequent condensation is an obvious method of water desalination and has a number of undeniable advantages. However, numerous attempts to implement a method of cavitation desalination of water using large-scale setups have not been successful yet. The purpose of this study is to obtain experimental dependence between the temperature and flow velocity of the desalinated liquid, the pressure in the cavity and its size, the geometry of the streamlined body and the volume of steam taken from the cavity in the prototype of a supercavitation desalination plant. Analyzing obtained data made it possible to show a sharp difference between gas and steam cavitation, the performance of the experimental setup in the desalination mode has been determined. It was concluded that the steam velocity in the condensate extraction pipeline is a factor limiting the condensate output. Based on the data obtained, specific design criteria for industrial supercavitation desalination plants were determined.
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Development of wear-resistant parts of high-manganese modified 110G13L brand steel
Статья научная
The efficient operation of the technological equipment of machinery manufacturing enterprises and heavy industry without distortion depends in many respects on the strength of their details. This requires the study of the process of operation of the details, which are mainly rubbed with each other. These methods are widely used in obtaining high-quality steel castings. The simplest method of processing steel outside the oven is modification. Modified carbon steel is much more economical in properties approaches to leached steel, while modified steel leached by saving and investigation approaches leached steel with valuable and rare additives (Ni, Mo, Ti and other). Modification with alkaline and alkaline-earth metals greatly increases the quality of steel. The quality of steel is positively influenced by nitride-forming modifiers.
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Effect of neodymium and erbium on the kinetics oxidation of Zn0.5Al zinc alloy, in solid state
Статья научная
Thermogravimetrical method studied the effect of alloying additions (on 0.01÷1.0 wt%) of neodymium and erbium on the oxidation kinetics of Zn0.5Al zinc alloy in the temperature range of 523-623 K. The values of the oxidation rate of the Zn0.5Al alloy and the alloy alloyed with neodymium and erbium, have been established in solid state. The behavior of ternary alloys with the participation of neodymium and erbium at the indicated temperatures somewhat differs from the oxidation of the binary Zn0.5Al alloy. For the eutectoid Zn0.5Al alloy, as compared with the alloys alloyed with neodymium and erbium, the minimum oxidation rate was noted. The addition of 0.5 and 1.0 % Nd and Er in the zinc alloy Zn0.5Al significantly increases its oxidizability. Alloy additions (on 0.01÷0.05 %) of neodymium and erbium slightly increase the oxidizability of the eutectoid zinc alloy Zn0.5Al. During the oxidation of the studied hard alloys, protective oxides pellicle are formed ZnO, Al2O3, Nd2O3, Er2O3, ZnAl2O4.
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Energy efficient modular block diagram of an air heat pump heat supply system
Статья научная
The use of air source heat pumps, together with other renewable energy devices and high efficiency heating equipment, together with digital control systems, is a promising European trend that continues to grow in the face of rising costs of traditional energy carriers. The article presents a number of technical energy-saving solutions, such as a mixing chamber for HHP, built into the heat supply system and the use of a supply and exhaust ventilation system, which is based on the principle of recuperation. A digital modular-functional-structural diagram of heat generation of a coolant from the environment is proposed. Based on the energy efficiency of the circuit solution with an electric boiler, a buffer tank and a patented mixing chamber, the authors achieve a rationally controlled heat and air exchange of a combined heat pump space heating system. Automation of the joint work of rationally selected elements of the heat pump air system is one of the Smart Home technologies that improve the efficiency of heat supply, create comfortable living conditions and security due to the digitalization of the control algorithm for this system.
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Статья научная
This paper covers the results of the composition and structure evolution of nanostructured materials produced by separate electrochemical oxidation of metals (copper and aluminum). The electrolysis products after short-term and long-term aging were characterized by XRD (X-ray diffraction) and DSC (differential scanning calorimetry) analysis. There is the difference in aging of nanostructures of copper- and aluminum-compounds. Short-term aging results in the phase transformation of copper(I) oxide and the stability of aluminum oxyhydroxide (boehmite). Copper (I) oxide is oxidized to copper (II) oxide and copper carbonate hydroxide. At long-term aging the oxidation of copper (I) oxide does not completed because the Pilling-Bedworth ratio for copper (II) oxide, copper carbonate hydroxide is greater than one. The structure of all copper-containing compounds (copper (I) oxide, copper (II) oxide, copper carbonate hydroxide) is changed. It results in the increases of both the interplanar spacing and the temperature of the phase transformations. Coherent scattering region (CSR) of boehmite and copper (I) oxide are 3-4 nm and 20-30 nm, respectively, and does not change at short-term and long-term aging.
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Experimental study of the effective insulation of building envelopes
Статья научная
The relevance of research is caused by the fact that at present, modern standards for saving thermal energy and thermal protection of buildings are focused on the use of a very limited set of solutions to reduce energy consumption, which do not always meet the specific conditions of construction and are often very expensive. A method for studying the effective insulation of building envelopes is proposed, taking into account the relationship between structural, heating, regime parameters and economic indicators. The goal is to determine the optimal value of the insulation thickness of the heat-insulating material, taking into account the thermal energy supplied to the object. The study used methods of mathematical modeling of heat transfer, optimization problem. An experimental study is presented, showing the possibility of applying the method of technical and economic optimization of thermal insulation of building envelopes. It was determined on the basis of the mathematical model of the thermal insulation of building envelopes developed by the authors, taking into account the regulation of the supplied thermal energy. The result of the study is to reduce the cost of heat losses through building envelopes and electrical energy for the regulation of the “heating, ventilation and air conditioning” system. The conducted studies testify to the expediency of using the proposed developments, which contribute to determining the optimal thickness of wall insulation with heat-insulating material, finding the minimum reduced costs, and an advantageous choice of a method for regulating the supplied thermal energy.
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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
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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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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