Технические науки. Рубрика в журнале - Бюллетень науки и практики
Статья научная
Harnessing and further development of the transit potential of Georgia are closely linked to the country’s overall socio-economic development, effective use of its advantageous transport-geographical location and, in general, the successful functioning of the Eurasian transport corridor. The growth in the volumes of freight flows and increasing competitiveness in the transport corridor, along with other factors, depends on the effective work of customs services of the countries located across the corridors. The establishment and implementation of a Single Automated System of Customs Clearance and Control of Transit Goods will be a step forward in effective management and control of transit procedures, which will significantly reduce the time of customs clearance of transit goods and contribute to the reduction of financial costs of the economic operators.
Бесплатно
Study of a laboratory circuit with a warm baseboard in pulse mode
Статья научная
The increasing global energy demand is a problem that people have been paying attention to, people’s demand for energy is increasingly urgent, and improving energy efficiency has become a hot topic in this century. Studies have shown that pulsating flow has an important effect on heat transfer, and it has been concluded in most literatures that turbulent pulsation can enhance heat transfer in different degrees. Pulsation heat transfer is a comprehensive heat transfer process, and the best heat transfer performance can be achieved only when the thermal resistance of each part is reasonably coordinated. Based on the principle of hydraulic shock, this paper develops a device with warm substrate which can be used to increase the pulsating pressure and enhance the heat transfer efficiency of pulsating flow. Firstly, the construction scheme of the experimental device is proposed, and the working principle of the experimental device is described in detail. The complex impedance, frequency function, amplitude-frequency characteristic and phase-frequency characteristic are obtained by mathematical transformation of power supply circuit. Finally, the frequency response of the circuit is constructed.
Бесплатно
Study of dynamic characteristics of clay solution under the influence of vibration
Статья научная
It is known that with the help of a vibrating sieve for vibration separation (separation) of a clay solution, the following technological problems are solved: cleaning the clay solution from drilled rocks and separating it into fractions, i.e. sorting. Signs of separation of drilled rocks from clay solution using vibration are the size of the drilled rocks, the shape and density of the clay solution itself, etc. It has been shown that in order to improve the basic technological characteristics of the vibrating sieve, it is necessary to study the behavior of the clay solution in the vibrating sieve.
Бесплатно
Study on heat transfer performance of non-integral capillary core sintered uniform plate
Статья научная
This paper mainly introduces the sintering process of the monolithic capillary wick and analyzes the influence of different copper powder particle size, filling rate, copper powder shape and heat source size on the heat transfer performance of the isothermal plate. The experimental results show that: (1) For the isothermal plate sintered with spherical copper powder, the capillary force of large particle size copper powder is small, but the flow resistance is also small, and the performance of the isothermal plate sintered with large particle size copper powder is better. (2) In the case of low filling rate, the isothermal plate is dried due to insufficient return fluid. In the case of high filling rate, on the one hand, the thickness of the liquid film at the evaporation end of the isothermal plate is large, resulting in additional thermal resistance. On the other hand, the thin film evaporation mode will be transformed into pool boiling mode, which will reduce the heat transfer performance. (3) Spherical copper powder sintered plate with regular shape has the best performance, while dendritic copper powder sintered plate has relatively high thermal resistance. (4) The heat source area has a great influence on the thermal resistance of the plate. Under the same heating power, the thermal resistance of the small area heat source is much higher than that of the large area heat source; The thermal resistance of sintered copper plate is lower than that of pure copper plate under two heat source areas.
Бесплатно
Study on the effect of diaphragm booster on the pulsed heat transfer of cooling system
Статья научная
This paper has developed a diesel engine cylinder liner and cooling water heat exchange enhancement device, including diesel engine cylinder liner, cylinder liner water cooler, hydraulic accumulator, check valve, diaphragm booster, centrifugal water pump, pulse valve and Conical tube. As well as the pulsating circulation system and booster system composed of equipment. The device heats the heat generated by the diesel engine cylinder liner in a pulsating circulation system through a cylinder circulator in a pulsating circulation system to exchange heat with the external low-temperature seawater. By controlling the opening and closing of the pulsating valve in the pulsating circulation system, fluid is generated in the pipe. Pulsing and hydraulically impacting the diaphragm booster connected near the pulsation valve pipeline, the fluid at the outlet of the diaphragm booster is subjected to hydraulic shock and circulates in a closed booster circuit connected to the diaphragm booster and passes through the cone during the flow...
Бесплатно
Test of the layout of the correction circuit with a plate heat exchanger
Статья научная
Pulse enhanced heat transfer technology is introduced, and a plate heat exchanger is designed. A pulsating valve is installed at the outlet of the heat exchanger to pulsate the heat medium. Pulsating and non-pulsating heat transfer tests are carried out on the same heat exchanger. On the basis of experiments, the effective temperature difference, heat flow and convective heat transfer coefficient of the heat exchanger at different pulse frequencies are analyzed by combining the theory of pulse enhanced heat transfer technology, heat transfer capacity, heat flow and convective heat transfer coefficient. Find the relationship between pulsation frequency of heat transfer effect of heat exchanger. The experimental results show that the heat exchanger has high heat transfer efficiency under the experimental conditions when there is pulsation.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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 (
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
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.
Бесплатно
