Технические науки. Рубрика в журнале - Бюллетень науки и практики
Testing of the model of the heat exchanger supercharger with a flat active part
Статья научная
This paper designs a pulsation-generating structure to provide pulsating flow for experiments. The relationship between frequency, flow and pulsating flow enhancement heat transfer is discussed separately. The characteristics of pulsating flow enhanced heat transfer are analyzed, and the theoretical research and engineering application of pulsating heat transfer are proposed. The scheme of the laboratory installation is developed, which is an independent circuit from the heat source with a pulse circulation of the coolant. The unit allows testing the heat exchanger-supercharger at different performance at the frequency of fluctuations of the coolant from 0.5 to 2 Hz. As a result of thermal tests, graphs of temperature changes over time in the heated and closed circuit at flow interruption frequencies from 0.5 to 1 Hz are obtained. It is found that with increasing frequency of flow fluctuations, the heating time of the coolant in a closed loop decreases by almost 1.85 times.
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The Process of Weaving New Types of Adras National Textile
Статья научная
This article describes our experimental research on the technology of production of a new range of national textille at the production enterprise Yodgorlik LLC in Margilan and its selling.
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Статья научная
Liner has a role as sealing or waterproof layer that was made to prevent water to be absorbed by the soil. A good liner is made within the minimum hydraulic conductivity (k) within the requirements of 1.0E-07 cm/s. This study was conducted to determine the extent on the difference between hydraulic conductivity (k) bentonite and termite nest ( Macrotermes gilvus Hagen) as one of the materials that have the potential to obtain small value of hydraulic conductivity (k). This research was conducted by examining the effect of hydraulic conductivity (k) value on the percentage of additives, such as bentonite and termite nest material ( M. gilvus Hagen), and then compared the hydraulic conductivity (k) values of those two materials. The variations in the additive content percentage are 5%, 15%, and 30% with laterite as a base material. Based on the results of falling head test at minimum density of 95% γdmax, the smallest hydraulic conductivity (k) value was obtained by bentonite with 30% mixed percentage level of 6.9390E-08 cm/s and the smallest hydraulic conductivity (k) value of termite nests was 1.2646E-07 cm/s with the content percentage of 5% mixture.
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The design of electric fire engine
Статья научная
The electric fire engine is based on the single chip microcomputer as the control core. In order to better realize the fire extinguishing function, the latest electric fire engine has added the tracking module, wireless transceiver module, etc., to realize the intelligent fire engine to detect the fire source and extinguish the flame. This design combines the principle of single chip microcomputer with the hardware and software circuit program to realize the function of automatic tracking and fire extinguishing, without the fire personnel risking their lives to carry out on-site operation. This kind of electric intelligent fire truck adds some practical small functions, brings us a lot of convenience, can better serve human beings. The main model of this design is a small toy car model with universal wheel and motor control wheel. The chassis is installed with a variety of sensors with different functions to achieve the purpose of moving forward and backward, steering and avoiding obstacles and eventually extinguishing the fire source. At the same time, the car can also realize wireless remote control. By comparing the shortcomings of the traditional fire truck, some improvements are made, the circuit diagram of intelligent control is designed, and the method of wireless control car for fire fighting is explored with the combination of practice and thinking, so as to further improve the fire truck and make it intelligent. The main purpose of this design is to reduce the fire casualties and improve the need for fire personnel to take the risk of life operation of the traditional fire truck function. Its advantages are automatic tracking, avoidance of obstacles, wireless control, measuring the source of fire.
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Статья научная
Among the alternative energy sources, of particular importance is the hydrogen energy industry, whose advantage over petroleum products consists in its high environmental safety and caloric content, inexhaustible natural reserves, its use in the internal combustion engines, and so on. Among the hydrogen-containing raw materials used in the fuel elements, particular attention is paid to hydrogen sulfide, which is disintegrated into sulfur and hydrogen. One of the biggest sources of hydrogen sulfide is the Black Sea, whose total volume is increasing annually by 4-9 million tons. The paper dwells on several methods for extracting hydrogen sulfide from the Black Sea basin, as well as associated difficulties. It also presents methods for the decomposition of hydrogen sulfide, of which special mention should be made on the plasma-chemical membrane technology.
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The energy circuit of the exhaust gas heat recovery circuit of a 25 kW diesel generator
Статья научная
The purpose of the work is to describe the installation using differential equations and obtain approximate values before the experiment. In this paper, a constructive scheme of the experimental device is proposed, and the principle of its operation is described in detail. The power circuit of the device has been drawn up. Complex impedance, frequency function, amplitude-frequency characteristic and phase-frequency characteristic are obtained by mathematical transformation of the power circuit. The frequency response of the circuit is constructed. As a result of the calculations, we will obtain the amplitude frequency response and the phase frequency response. Using the found values of the characteristics, we will build graphs and draw conclusions about how the characteristics depend on the change in parameters and why the graph lines of the graphs are exactly the way they are.
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The grape skins and seed polyphenolic extracts
Статья научная
The paper dwells on identification of phenolic compounds and anthocyanins from newly-squeezed grape skins and seed ethanol extracts of Zeibeli and Izabela color grape varieties cultivated in viticulture-winemaking micro-zone of western Georgia, by combined gas chromatography mass-spectrometry, and their determination by method of high-pressure liquid chromatography, but antioxidant activity has been assessed by DPPH method. For the experiment, we used newly-squeezed grape skins and seed without drying, mechanical and thermal treatment. Total phenolic compounds content in grape skins and seed ethanol extracts of Zeibeli variety (>423 mg/100 ml) was greater than in grape skins and seed extracts of Izabela variety (>394.2 mg/100 ml). The same results have been registered when assessing antioxidant activity of extracts. In particular, in the conditions of the same dissolution of extracts, grape skins and seed ethanol extracts of Zeibeli variety had higher antioxidant activity (up to 67-79,4%) than grape skins and seed extracts of Izabela variety (49.5-63.9%). Studies have shown that total phenols and anthocyanins quantitative content correlates with antioxidant activity of extracts. The polyphenolic contents and the antioxidant activity of the skins and pulps of different grape cultivars were estimated using HPLC and DPPH antioxidant assay, respectively. The phenolics and flavonoids identified were quercetin, kaempferol, caffeic acid, p-coumaric acid, cinnamic acid, and (-)-epicatechin. The total phenolic contents were found to be the highest in the grape skin of Flouxa (> 400 mg/100 g), followed by Campbell Early and Tamnara (> 300 mg/100 g), and then by Red Globe and Ruby Seedless (> 250 mg/100 g), and the total phenolic content was the lowest in Italia and Delaware (
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The loop with heat recovery of diesel generator lubrication system
Статья научная
In recent years, with the increasing severity of energy problems, more and more energy-saving technologies and enhanced heat transfer methods have been valued. Pulsating flow enhanced heat transfer technology as a branch of enhanced heat transfer, has a wider application background in industrial production and living areas. In the research process of this paper, an experimental platform is built according to the requirements of pulsating enhanced heat exchange and dual-circuit cooling. Through the experimental research on the double-loop air cooling of the fluid in the tube with pulsation, the influence of various parameters and pulsating characteristics of the pulsating fluid on the enhanced heat transfer is analyzed; the temperature of the inlet and outlet of the device under normal conditions and the flow of the fluid under the condition of pulse are measured through a temperature sensor. The outlet temperature was compared with the analysis, and the measurement data was calculated and analyzed. Experimental results show that the pulsation of the fluid has a significant effect on the heat transfer effect, and the effect of the flow rate on the pulsation enhanced heat transfer is significant. When the flow rate is small, the phenomenon that the fluid does not generate pulsation or pulsation is relatively weak, which cannot cause strong disturbance of the fluid in the heat exchange section, so that the heat exchange cannot be enhanced, and even the heat exchange is weakened; as the flow rate gradually increases, the heat transfer coefficient is enhanced.
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The loop with pulse circulation of oil for fuel oil heating
Статья научная
The energy issue is an important strategic factor that determines the sustainable development. Fuel oil is the main raw material in most power plants and boiler houses. Energy conservation is an important issue in the 21st century. This article focuses on pulse circulation for heating fuel oil. The heating system of fuel oil with pulsating circulation of oil in the heating circuit can be provisionally represented as an energy chain consisting of separate links and functioning as a single whole. In the master's thesis the process of heat transfer from the vibrating bellows heater to fuel oil was investigated. On the basis of the conducted experiments on the heating of fuel oil, it has been shown that when the bellows heater oscillates with significant amplitudes, the boundary layer breaks down, and the heat transfer is affected mainly by forced convection, in experiments it amounts to 4-8% of the total heat flux of the bellows heater in the barrel with fuel oil.
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Статья научная
The theoretical aspects of statistical analysis on fruit and vegetable farms’ activity, the system of statistical indicators and their practical application will be discussed in this article. The stages of statistical analysis on farms specialized in fruit and vegetable yielding, the system of statistical indicators and the main tasks are given. The article deals with the development of farms specialized in fruits and vegetables and exclusive features of their activity. The farms’ main development tendencies, determined problems, given available ways to solve these problems and factors to the modernization of fruit-vegetable field are analyzed.
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The power circuit of mechanical damping device for cooling system of 50 kW pulse diesel generator
Статья научная
Diesel generators have advantages such as high reliability, superior economic performance, and a wide range of applications. However, its working environment is relatively sealed, and it is difficult for the internal heat of the motor to transfer to the outside. Prolonged high temperatures can affect the operational performance of the motor and even cause danger. Therefore, it is necessary to design a reasonable cooling system to ensure its efficient operation within the safe working temperature. The water-cooled cooling system has good heat dissipation performance, consisting of components such as a water pump, radiator, fan, water tank, and temperature controller. By precisely controlling the water flow rate and wind speed, effective control of the internal temperature of the generator is achieved, extending the service life of the equipment. This article studies the power circuit of the mechanical damping device in the cooling system of a 50kW pulse diesel generator, develops heat transfer and hydraulic energy circuits, and constructs the frequency response of the circuit. As the water quality increases in the circuit, the amplitude decreases at low frequencies (less than 4 rad/s) and frequencies close to 10 rad/s, and the amplitude aligns. For one parameter variable, the optimal frequency is 3-4 rad/s.
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The review of the water mist fire extinguishing technology
Статья обзорная
Due to the signing of the Montreal Convention, people have been looking for alternatives to the halon fire extinguishing system. The water mist is widely concerned because of its unique advantages. Many scholars have conducted extensive research on water mist fire extinguishing technology. This paper makes a review of the development and research results of the water mist.
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Статья научная
In this paper, a three-stage series power generation system is designed. The waste heat generated by the engine is used as the heat source, and the energy released before LNG liquefaction is used as the cold energy. It is used to improve the performance of the system by increasing the carbon dioxide transcritical cycle. With the target of maximum generation capacity and exergic efficiency, exergic pressure and condensation pressure in the system were selected for the most beneficial generation capacity and efficiency of the system through analysis of exergic pressure and evaporation pressure.
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Thermal-hydraulic performance analysis cold side of the plate heat exchanger using water-water
Статья научная
In this research, the thermal-hydraulic performance of plate heat exchanger (Ridan HHN no. 04) used in domestic water system is investigated experimentally. The hot water inlet keeps temperature and flow rate constant at 70 C and 0.1 l/s, the cold-water inlet remained 110 C with different velocity. The heat transfer coefficient can reach maximum when velocity of cold water is 0.2 m/s. Then the convective heat transfer coefficient increases with enhancement of Reynolds number and it is stable after more than 1200. Moreover, it is observed that Fanning friction factor decreases with an increase of the Reynolds number and it is showed by the empirical correlation. Therefore, it is possible to find that the increase of the Peclet number results in an increase of the Nusselt number as well when Peclet number small than 200. Finally, we get reference idea how to be cooling in the particular case using plate heat exchanger.
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To the problem of TV innovations in the near future
Статья научная
This article describes the innovation in technology services. In the process the information about some new and improved gadgets was received. Today this area is evolving and the article discusses three new inventions that will help all mankind in the future. This theme is most relevant to the technical specialists, or people who are fond of TV.
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To the question on the technology of koumiss production
Статья научная
This article is devoted to the analysis of methods of production of koumiss. Koumiss, unlike kefir, has a more delicate, soft and gentle sour-milk taste, and aroma has tender flakes of casein. The ways of making koumiss are described. An accelerated, easier method of preparing koumiss without maturation and without prolonged mixing is known. However, this method was not widely used. The article describes that the technological regimes for the preparation of koumiss are controlled only organoleptically. The general techniques in the technology of making koumiss are revealed: thelong-term fermentation method and the method of short-term fermentation. The article shows the technology of koumiss production. The inventions of koumiss preparation are considered. It is concluded that there is a need for physicochemical studies of koumiss production and the establishment of its optimal regimes for Kazakhstan.
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Статья научная
Proton exchange membrane fuel cells (PEMFCs) are vital energy-conversion devices in a hydrogen-fueled economic. In this study, we performed density functional theory (DFT) calculations to study 4e- oxygen reduction reaction process on transition metal embedded in single and double vacancies (SV and DV) in a graphene. We calculated bonding energy and adsorption energy on CoX3 (X = B, C, N, Si, P and S) and CoX4 (X = B, C, N, Si, P and S) embedded in graphene. Our DFT results indicate that formation of CoX3 is unfeasible and the formation of CoX4 is feasible. In addition, the crucial role of ligand atoms near embedded metal atoms is revealed via the molecular orbital theory. Then the Gibbs free energy of CoX4 are calculated and the CoN4, CoS4, and CoP4 are predicted to be active for catalyzing ORR, and these also show ligand atoms’ coordination effect for catalytic activity of central metal. Furthermore, we observed that they have identical rate-determining step (RDS). This work can provide some references for transition atoms catalytic doped in carbon materials.
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Underwater robot technology and future trend analysis
Статья научная
Underwater positioning and navigation is a technology that provides the attitude, speed, position and other information of underwater robots. It is the premise for underwater robots to successfully complete various underwater tasks. The underwater environment is complex and changeable, and a single positioning and navigation technology will inevitably not meet the needs of long-range, multi-target and high-precision. The navigation system of the future underwater intelligent robot integrates the integrated navigation mode of various technologies. This paper discusses the basic underwater positioning and navigation mode and integrated navigation mode, describes the development process of underwater positioning and navigation technology, compares the research methods and progress of Chinese and foreign scholars, analyzes the current research bottlenecks and technical difficulties, and points out the direction for future research, which can be used as a reference for the follow-up research of underwater robot positioning and navigation system.
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Warehouse problems in logistics. Systems and their digital solutions
Статья научная
Warehouse operations are the lifeline of all companies doing business in Uzbekistan and around the world. Good warehouse management keeps products flowing efficiently through the system, which is a critical factor in serving customers and securing increasing profit margins. When warehouse operations are smooth, the entire company can organize a reliable supply chain to prevent shortages and holdups.
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Ways to protect equipment from hydraulic shock
Статья научная
The hydraulic equipment is experiencing damage to its components and even the mechanical equipment owing to hydraulic shock induced by a sudden rise in load, resulting in a step reaction in the hydraulic system. An analysis of the hydraulic system is conducted to protect the equipment from the detrimental effects of hydraulic shock. This analysis includes examining components such as the hydraulic damper, centrifugal pump, accumulator, control valve, and others. The primary function of the power component is to mitigate hydraulic stress by altering the pump’s flow rate. The control element initiates the reversing of the valve in the hydraulic system in order to mitigate hydraulic shock. The auxiliary components primarily concentrate on enhancing the efficiency of the accumulator and maximizing the synergistic utilization of damping components. By adjusting the input value, one may regulate the flow rate and pressure of the system. The discussion revolves around finding the most efficient frequency in the shortest amount of time.
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