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Бюллетень науки и практики @bulletennauki
Статьи журнала - Бюллетень науки и практики
Все статьи: 6432
Статья научная
This article presents current issues of gradual, systematic and continuous improvement of organizational and economic mechanisms of development of small business and private entrepreneurship in service sphere of Uzbekistan as well as ensuring a unified integrated approach to solve problems in support of this sphere. It is assumed that the implementation of the above reforms will lead to further improvement of the organizational and economic mechanisms for the development of small business and private entrepreneurship not only in the field of service but also in economic sectors. In addition, the article contains the following legislative acts, their content and essence, and scientific recommendations.
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Current state of wild Pistacia lentiscus in Azerbaijan
Статья научная
Information is provided on Pistacia lentiscus L. belonging to natural forest vegetation, Anacardiaceae family, Pistacia genus. Information is given on the modern status and importance of Pistacia lentiscus L., which is one of the wild tree species in the flora of Azerbaijan. Due to its resin content, the Pistacia lentiscus is a valuable plant that is resistant to pests and used in various fields. The Pistacia lentiscus is a long-lived tree that coexists with other forest plants.
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Current status and development of contemporary high temperature heat pump technology
Статья научная
With the continuous deepening of the concept of energy saving and emission reduction, heat pumps have been widely applied to life. With the improvement of heat quality, the corresponding condensation temperature of heat pump devices is required to be high. Therefore, high temperature heat pumps have become a hot topic, looking for a high-temperature heat pump working fluid is an effective way to develop a high-temperature heat pump device. Exploring a new heat pump cycle mechanism is also an effective way to generate a high-temperature heat pump device. This paper combs the research status of high temperature heat pump in the field at home and abroad and analyzes the existing high temperature heat pump working medium and high temperature heat pump circulation mechanism, mainly expounds the principle of the existing high temperature heat pump technology.
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Current status and taxonomical composition of the natural dendroflora of the Hirkan National Park
Статья научная
The current state of the natural dendroflora of the Hirkan National Park was analyzed, an inventory of natural and cultivated plant species was carried out, the impact of climate change on biodiversity, the taxonomic composition of trees and shrubs, dominant species, and the distribution areas of the studied plants were comprehensively studied. In the forest ecosystem of Hirkan National Park, the area where the plants live change in several directions. In the deep layers of the forest, the sun hits a small amount. The level of illumination depends on the composition, age, density and geometric dimensions of the trees and shrubs that make up the forest. Depending on the amount of light, more or less shade-tolerant species grow in the lower tiers of the forest. Hirkan National Park has undergone anthropogenic impact in recent years. The forest usually consists of 2-3 tiers.
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Dermatitis caused by stress in quails and measures to combat them
Статья научная
The research work was carried out in the vivarium of the Faculty of Veterinary Medicine of ASAU and in the Education-experimental Center for Quail Breeding on White texas breed quails in the period of temperature stress in the building and under the shed. When quail broods are kept under shed in June, July, August, temperature stress occurs among quails as a result of air temperature higher than 38-42°C, and as a result, large changes in homeostasis occur, as well as due to prolonged sunlight during the day, as in ornamental birds. Dermatitis disease also occurs among quail birds. Dermatitis disease is different - allergic, chemical, physical, etc. arises under the influence. The article shows ways to prevent dermatitis caused by temperature stress and strong sunlight. 100 grams of Anti Stress Forte WSP drug was added to 120 liters of water in order to prevent the formation of large changes in homeostasis and the formation of the photo-contact form of dermatitis on the skin of quails as a result of temperature stress during this period, as a result of the rise in temperature and the long duration of direct sunlight should be applied, in case of prolonged exposure to the sun’s rays, a curtain made of white polyethylene should be placed on the front part of the shed. While investigating the dermatitis disease caused by temperature stress and long-term exposure to sunlight, we determined the clinical-physiological condition and productivity of the mother quails.
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Description of women in Jawahir ul-ajaib
Статья научная
The article provides information on the first memoir devoted to women Jawahir ul-ajaib by Fakhriy Hiraviy, and the manuscript copies of the memoir stored in libraries around the world. You can find out about the quantity of art forms in the Jawahir ul-ajaib as well as the number of women and their work.
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Design and analysis of antireflection layer on the surface of crystalline silicon solar cell
Статья научная
With the positive development of photovoltaic technology, improving efficiency and reducing cost has become a global problem facing the solar industry. The development of solar cell anti-reflection film can significantly reduce the reflection of sunlight on the surface of the battery, increase the flux of light entering the battery, and create more photo-generated carriers, which is the most economical and effective way to improve the efficiency of the battery. More photo-generated carriers are produced, which is the most economical and effective way to improve the efficiency of batteries. Therefore, it’s of great value to explore a performance-matched antireflective film material for solar cells and its preparation process. The plasma enhanced chemical vapor deposition of silicon nitride antireflective coatings has been widely used in photovoltaic industry. The aim is to form an antireflection film on the surface of crystalline silicon solar cells and achieve good passivation effect. The thickness and refractive index of the antireflective film have an important influence on the performance of the battery. It is of great significance to explore the optimum technological conditions for preparing the optimum thin films. Considering the optical properties, stability, preparation process and production cost of antireflective film materials, the influence of antireflective film on the output characteristics of solar cells was studied by using PC1D simulation software.
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Design and analysis of heat pipe heat exchanger efficiency
Статья научная
The heat pipe has a high thermal conductivity, and its basic working principle is to transfer heat through evaporation and condensation through the working medium inside the pipe. Heat pipe has good thermal conductivity, isotherm and other characteristics, and the heat transfer area at both ends can be changed at will, control the temperature and other advantages. Therefore, the heat pipe heat exchanger has the advantages of high heat transfer efficiency, compact structure, small fluid resistance loss, and beneficial to control dew point corrosion. At present, it has been widely used in metallurgy, chemical industry, oil refining, boiler, ceramics, transportation, light textile, machinery and other industries, as energy saving equipment for waste heat recovery and heat energy utilization in the process and has achieved remarkable economic benefits. The design of the heat pipe heat exchanger on the development of the current situation, development trend, application, design principle and design process of a simple description, while focusing on the discussion of the heat pipe heat exchanger design process. The main content of the heat exchanger thermodynamic calculation, structural design and material selection. The model of heat pipe heat exchanger is established according to the actual situation and the calculated data.
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Design of PFC converter based on interleave boost
Статья научная
Based on the principle of stagger boost PFC, this paper expounds the application value of stagger PFC theory by developing a scientific and feasible scheme and using Matlab simulation. According to the subject requirements, the use of UCC28070 to achieve PFC control function. And learn IC functions. Based on the theory of interlaced PFC, the most suitable electronic device is selected to adjust each part of the circuit. Finally, Solidworks and Protel software were used to draw the radiator and PCB boards, then the prototype was made and debugged, and the final result was obtained.
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Статья научная
The subject of the research is designing a regenerative heat exchanger to heat hot water. Qualitative and quantitative analysis of relevant physical parameters to optimize heat exchanger models. The purpose of this study is to simulate realizing the goal of heating hot water with 25 kW and optimize the model to optimize the heat exchange efficiency in practical work. As a result of the research, Amplitude-frequency response of the circuit increases linearly as speed of rotation. When the speed is constant, the less of water mass is, the value of Amplitude great. The phase frequency response of the circuit increases overall as the speed increases. The greater the mass, the greater, and the rate of increase gradually decreases. we know that increasing the water volume can improve the heat transfer efficiency, but when the water volume (G) increases to 1.6, the rate of increasing the heat transfer efficiency begins to decline, so this should be taken into account in the design process. With the heating time increases, the heat transfer efficiency will also improve. It should be noted that when the heating time increases, the rate of increase of heat transfer efficiency decreases and specific heat capacity (KF) decreases.
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Design of a liquid cooler for a 100 kW semiconductor power converter
Статья научная
He focus of this research in this paper is to design a 100 kW power liquid cooler, semiconductor converter liquid cooler, thus using pulsed thermal medium circulation to increase the capacity of the cooling system on the surface of the power semiconductor device. Based on comparing the parameters of conventional and pulsed coolant circulation mode, the liquid cooling system of power semiconductor converter is studied by physical method. In laboratory testing, experiments are planned according to the order and frequency of changing device operating modes. Finally, the experimental research results are processed, and the relationship between the discharge heat power and the temperature drop and the coolant flow is established by using the mathematical statistics method. Result: Depending on the exhaust heat power and the coolant flow in the range of 3-1.5 L/min, the pulsating heat transfer enhancement in the liquid cooling system of the power semiconductor converter can increase the thermal capacity and the current load of the power semiconductor converter by a factor of almost 2.5 times, respectively. At the same time, the circulation of the coolant in the inner circuit is carried out by a hydraulic powered film pump.
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Design of dangerous driving behavior detection system based on STM32
Статья научная
With the rapid development of China’s economy and the continuous improvement of the living standards of the people, cars have gradually become an indispensable tool for travel. At the same time as the number of cars increases rapidly, the accident rate of road traffic is also increasing. Traffic accidents caused by dangerous driving behavior account for a large part of the accident rate. In order to reduce the road traffic accident rate, a vehicle dangerous driving behavior detection system using STM32 single-chip microcomputer is designed from the vehicle itself, which mainly detects the speed and weight of the vehicle. When the vehicle is in the starting state, the detection system detects the weight and speed of the vehicle in real time through the sensor and the motor speed. In this system, the STM32 is used as a core MCU. When the speed or weight of the vehicle exceeds the threshold, the MCU performs an alarm and subsequent operations. This design introduces the overall design of the system in detail, from the test of each module to the use of the overall connection test, the interface module and STM32 interface circuit as well as the system hardware circuit and related peripheral circuits are given, and finally the measurement data is displayed through the OLED. The design is simple in structure and can be applied to various vehicles.
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Design of fishing vessel lighting system based on force-controlled wind-solar complementarity
Статья научная
This paper focuses on the lighting system of fishing vessels, and the emergence of histograms has brought a new vitality to the development of the lighting of fishing vessels. In this paper, after summarizing the knowledge of wind and solar complementary technology, combined with the design needs to use the configuration control of each part of the control function to put forward a series of control schemes. Explains the background of the project development and its importance and introduces the key technical situation of the wind and light photoelectric complementary and the use of solar wind energy in the ship. Master the wind and solar complementary technology overview and summarized the independent wind power generation system and independent photovoltaic power generation system technology as well as the characteristics and working principle of wind and solar complementary power generation. Obtain the specific parameters of each component, including marine lighting parameters, wind turbine parameters, photovoltaic solar panel power generation parameters, in order to prepare for the simulation afterwards. Software base before simulation, simulation according to the requirements of the design, including the design of wind turbine, photovoltaic solar panels, the design of the fishing boat lighting load, and finally the results of the simulation are analyzed as well as the conclusion.
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Design of heat pipe air preheater for 10 t/h gas-steam boiler
Статья научная
This design is aimed at energy -saving and designed a heat pipe air preheat to recover 10 t/h steam gas boiler flue heat waste heat, thereby increasing the efficiency of the boiler and reducing gas consumption. This article first introduces the thermal pipe, heat pipe heat exchange, and boiler thermal system, and then focus on the design and optimization of the heat pipe air heater. This design optimizes the thermal pipe specifications of the heat pipe air heater and the parameters of the fins. At the same time, the sealing structure, the fixed structure, and the airport structure are optimized. Subsequently, the UG software created a three-dimensional physical model model and rendering model, and finally proposed corresponding countermeasures on equipment corrosion, thermal pipe life and tube vibration problems. This design uses Excel software to make design calculation tables. Through input parameters, the results of the results of the number of thermal pipes can be obtained.
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Design of metal sulfide electrode for hydrogen production by electrolysis
Статья научная
Hydrogen evolution reaction (HER) is the cathodic hydrogen evolution reaction in electrolytic cell, but the hydrogen evolution catalytic properties of electrode materials best remains is the precious metal catalyst, therefore, in order to study the catalytic performance is good, and cheap hydrogen evolution electrode materials has become the research hot spot, metal sulfide can be mixed and with good electrical conductivity is it can be used as a necessary condition for hydrogen evolution electrode, The core theory of this paper is the first principle. By taking metal sulfide as the matrix and doping it with 10 metal group elements, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, we obtained the configuration of 20 metal sulfide by doping it at two different sites of S atom, and inlaid H atom into metal atom. Then, through the use of software to study its catalytic performance, through the free energy analysis, rate analysis, bond length analysis, density of states analysis, charge analysis method, compared and found the most suitable doping metal element V, thus also determined that metal sulfide can be used as hydrogen evolution electrode through metal doping.
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Статья научная
As a new type of heat exchanger with compact structure and efficient performance, microchannel heat exchangers have good application prospects in industries with strict requirements such as energy and power, petrochemical, aerospace, and other industries. Therefore, exploring the performance and heat transfer characteristics of microchannel heat exchangers is of great significance. This article designs a performance testing system that can simultaneously explore the enhanced heat transfer inside the pipeline of water water and carbon dioxide compressed air microchannel heat exchangers. The variable working fluid circuit design is used to analyze the factors that affect the enhanced heat transfer. The Control variates is used to control the heat transfer conditions, explore the difference of heat transfer performance between different working fluids under different flow rates, inlet temperatures and other conditions, and analyze the heat transfer performance of different channel types by comparison method. The results indicate that when the hot water flow rate range is 2.063×10-5~2.556×10-5m3/s, Re-5~2.556 ×10-5m3/s, the Reynolds number and Nusselt number in the pipeline increase with the increase of inlet flow. In the carbon dioxide compressed air heat transfer experiment, when the flow rate range is 2.810×10-4~3.182×10-4m3/s, the Nusselt number and convective heat transfer coefficient of the 3.6mm inner diameter microchannel are always greater than the Nusselt number and convective heat transfer coefficient of 6.6mm. When the pipe diameter is the same, the water water microchannel heat exchanger has better heat transfer performance and smaller pressure drop compared to the carbon dioxide compressed air microchannel heat exchanger.
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Designing a cooler with natural cold for a 100 kW semiconductor power converter
Статья научная
The subject of the study is the design of a cooler with natural cooling capacity for a 100 kW semiconductor power converter. The purpose of this thesis is to design a cooler with natural cooling capability for a 100 kW semiconductor power converter and to evaluate its practical effects. We summarize the demand for power semiconductor devices for new applications in power electronics in recent years. During the study and testing of the cooler for the 100 kW semiconductor power converter, the parameters that became the basis for mathematical modeling were determined. In this paper, we summarize the key issues and the current state of research on power semiconductor modules, including module thermal design and thermal modeling issues. The degree of realization is complete. In the process of developing the experimental device, reduction of energy consumption losses and reduction of explosion and fire hazards in industrial production facilities was achieved, which in turn will increase the efficiency of the invention and reduce its production costs. Development of efficiency - reduction of power consumption losses, reduction of explosion and fire hazards in industrial production facilities due to overheating of power semiconductors.
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Статья научная
As in the Republic of Azerbaijan, appropriate measures are being taken in the Guba district in the field of environmental policy, environmental security, and efficient use of natural resources that meet the needs of society and require environmental protection in order to achieve sustainable socio-economic development. Therefore, the interaction of society with nature, the optimization of the impact of these relations, and the search for solutions are considered as one of the important issues. In this case, the main attention should be paid to the organization of the designing the industrial zones Phin the Guba district. Because the correct designing of industrial zones helps to organize work, protect the environment, and achieve sustainable socio-economic benefits. The article presented as a result of research in this area examines the volume of industrial products produced in the Guba district, the retail trade turnover of local production and export products, design of industrial zones, and environmental problems during production.
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Designing of a cavitation heat generator for heating water with a capacity of 10 kW
Статья научная
This article establishes a three-dimensional model of the design circuit of a water heating cavitation device and simulates it in Hysys software. The relationship between temperature, pressure and flow rate of cavitation generator in pulsed heating water circulation unit is studied by using control variables. The dependence of pressure and temperature difference on flow rate was studied. The dependence of pressure and temperature difference on the thermal power of the cavitation device was studied. The dependence of pressure and temperature differences on pipeline diameter was investigated. Explored the differences in pressure and temperature through water flow methods in pulse and stationary modes. The following conclusions can be drawn: 1) When the flow rate and output thermal power remain constant, the pipe diameter is inversely proportional to the pressure; 2) When the pipe diameter and output thermal power remain constant, the flow rate is proportional to the pressure; 3) When the total output power is 10 kW, the outlet temperature of the system gradually rises to a relatively stable state after 1000 seconds for different power cavitator schemes; 4) When the total output power is basically equal, the more times the parallel connection is made, the smaller the voltage drop, and the higher the system efficiency; 5) When the pipe diameter and output heat power are constant, the larger the flow rate, the smaller the temperature after the cavitator and the temperature difference between the front and back become smaller. When the pipe diameter and flow rate are constant, the smaller the output thermal power, the smaller the temperature after the cavitator and the temperature difference between the front and back become smaller.
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Designing of a liquid cooler with a phase transition with a power of 5 kW
Статья научная
A diagram and installation of a prototype of a two-flow heat pipe with the ability to regulate the parameters of the working environment have been developed. The installation allows the heat pipe to operate in both normal and pulsed cooling modes. Data were obtained that made it possible to obtain the dependence of the heat transfer coefficient on the heater power, and the heat transfer coefficients in stationary and pulsed modes were determined. In this article, the Aspen Hysys software package is selected as the software and circuit simulation. As a result of theoretical studies, it was established that the heat transfer coefficient of a heat pipe in pulsed mode is 12% higher than in stationary mode with the same initial coolant parameters. Based on the results of the work, it is proposed to use the method of pulsed supply of liquid coolant as one of the ways to increase the heat transfer of a heat pipe.
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