Исследования. Проектирование. Опыт эксплуатации. Рубрика в журнале - Журнал Сибирского федерального университета. Серия: Техника и технологии
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
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
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
