Технические науки. Рубрика в журнале - Бюллетень науки и практики
Electric vehicle charging scheduling and pricing based on Stackelberg game
Статья научная
The disorderly charging and discharging of a large number of electric vehicles will have a serious negative impact on the safety and economic operation of the power system. In order to avoid safety problems and obtain maximum economic benefits, a master-slave game is proposed to model the maximization of profits for agents and car owners. In the upper model of the model, the optimization objective of the main body is to minimize the operating cost and minimize the load mean square error; in the lower model, the goal is to minimize the cost of electric vehicles; the particle swarm algorithm is used, and the model decoupling characteristics are used from the inside to the outside. Solve the Nash equilibrium point of the optimization model, obtain the set of optimal time-of-use electricity price and electric vehicle charging and discharging scheme, and finally obtain the global optimal pricing strategy. Various typical scenarios before and after optimization are compared and analyzed in detail through calculation examples, and the effect of the proposed model and the overall scheduling benefit are verified.
Бесплатно
Energy circuit of 1.3 MW with Brayton cycle
Статья научная
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
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
Краткое сообщение
Presents the results of studies (research) on the use of silica raw materials from the production waste of refinement tailings of antimony ores (or antimony ores refinement tailings) and basalt fiber waste, their influence on the quality characteristics of non-autoclave aerated concrete.
Бесплатно
Enhanced heat transfer of heat-exchange equipment by pulsating air flow
Статья научная
This paper designs a pulsating generator to provide pulsating air flow for experiments the relationship between the average flow velocity, pulse and pulsation amplitude and the pulsating flow enhancement heat transfer ratio was discussed respectively. The characteristics of the pulsating flow enhanced heat transfer were analyzed, and the academic research and engineering application of pulsating heat transfer was proposed. This inevitably has an optimal pulsating frequency value at which the maximum vortex generation can be obtained within one pulsation cycle to obtain maximum heat transfer effect, for example, in this experiment; the optimal frequency is 1-1.25 Hz. The effect of Reynolds number Re on the low-frequency pulsation convection heat transfer process is that the low-frequency pulsation can only enhance the convective heat transfer within a certain range of Reynolds numbers. If it exceeds this range, the convective heat transfer is weakened.
Бесплатно
Статья научная
Study of urban public transport management on the basis of logistical approach today is of high relevance. For a long time, logistical concepts in transport have only been applied in the freight transport field of activities. However, logistical principles might be meaningful for systemic organization and management of civil passenger traffic. The given paper describes the use of logistical approach and technique in passenger transport, as a logistical chain of operators and infrastructure interacting through logistical links allowing for optimizing the production of transport services, meeting the needs of different population categories through the proper management of available economic resources. The paper proposes the use of logistical approaches in the systems of urban public transport. They should help to formulate the new principles of management, planning and control over material and their attendant flows, and to become the main competitive advantage in the market of transport services.
Бесплатно
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 lubrication/water inlet keep temperature and flow rate constant at 72 °C and 0.8-0.1 L/s, the cold-water inlet remained 12 °C with different velocity. Then the convective heat transfer coefficient increases with enhancement of Reynolds number. Moreover, it is observed that Fanning friction factor decreases with an increase of the Reynolds number and it is showed by the figure. 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 in water - water smalls than 2500. Finally, we get heat exchanging performances of cold side in lubrication/water - water using plate heat exchanger.
Бесплатно
Experimental research on heat dissipation at the hot end of semiconductor refrigeration chips
Статья научная
TEC1-12705 and TEC1-12706 two types of semiconductor refrigeration chips were designed with different hot-end heat dissipation conditions. At the same time, a test device for heat dissipation of heat pipes for heat sinks with separate current input and two-stage refrigeration was designed, and the influence of hot-end heat dissipation conditions on cold-end temperature was analyzed. The test results show that the cold terminal temperature of the semiconductor refrigeration sheet is related to the heat dissipation capacity of the hot terminal. Under the condition of limited heat dissipation capacity, the cold terminal temperature decreases first and then increases with the increase of the input current; and under the condition of ensuring the heat dissipation capacity, the cold terminal temperature decreases with the increase of the input current and decreases with the decrease of the hot terminal temperature. The two-piece TEC1-12706 semiconductor refrigeration sheet adopts two-stage refrigeration with separate current input, and the minimum temperature of the cold terminal can reach -36,8°С. The test results show that improving the heat dissipation conditions of the hot end can improve the performance of a single semiconductor refrigeration sheet. At the same time, under the best heat dissipation conditions, the use of separate current input two-stage refrigeration can greatly reduce the temperature of the cold end, which is of great significance to improve the working temperature difference of the semiconductor refrigeration sheet.
Бесплатно
Experimental study of cavitation heat generator for heating water
Статья научная
The energy released by cavitation is a new method to make full use of energy. Based on this, a new type of cavitation heat generator for heating water is designed. A conical core is used instead of the traditional throttling element to build a set. Closed circulation system device, the performance of the cavitation heat generator when the cone core with different cone angles was tested in the test. The temperature difference and pressure difference before and after the three groups of liquid medium flow through the cavitation heat generator were measured experimentally. The results show that the cavitation heat generator with a 30-degree tapered core has the best performance and improves the heating efficiency of the feed water, which has a great reference value for the further study of cavitation heat transfer.
Бесплатно
Experimental study on a pulsation-enhanced heat transfer device
Статья научная
The pulsation-enhanced heat transfer technology is introduced, and a volume coil heat exchanger is designed. A pulsation valve is installed at the heat exchanger outlet of the heat exchanger to pulsate the heat medium, and the same heat exchanger is subjected to pulsation and non-pulsation heat transfer tests. Based on the experiments, combined with the theory of pulsation-enhanced heat transfer technology, heat transfer capacity, heat flow, and convective heat transfer coefficient coefficients, the effective temperature difference, heat flow, and convective heat transfer coefficient of the heat exchanger at different pulse frequencies are analyzed. The relationship between the pulsation frequency of the heat transfer effect of the heat exchanger is obtained. The test results show that the heat exchanger has higher heat exchange efficiency when there is pulsation under the test conditions.
Бесплатно
Experimental study on heat transfer and pressure drop in plate heat exchanger using water-water
Статья научная
It would be misguiding to consider only cost in design of a heat exchanger because high maintenance costs increase total cost during heat exchanger’s services life. Therefore, exergy analysis and energy saving are very important parameters in heat exchanger design. In this study, the effects of pate heat exchanger (PHE, Ridan HHN no. 04) on heat transfer, friction factor and exergy loss were investigated experimentally. Experiments were conducted from laminar flow condition to turbulence flow condition under counter flow condition. Reynolds number and Prandtl number were in the range of 220
Бесплатно
Experimental study on heat transfer of pulsating flow enhanced the plate heat exchanger
Статья научная
We conducted two sets of experiments, one is under steady-state conditions and the other under pulsating conditions. We focused on measuring the heat transfer characteristics of plate heat exchangers under different pulsation conditions. In the experiment, we control the mass flow of the hot fluid to circulate at a rate of 0.722 kg/s. The mass flow rate of the cold fluid is 0.05-0.18 kg/s, and the pulsation frequency is 0.45-2.23 Hz. We measured different mass flows at different pulsation frequency. The data analysis shows that when the pulsation frequency is 1.78 Hz, the heat transfer coefficient reaches a maximum of 4415.73 w/(m2·k), and the corresponding cold fluid mass flow rate is 0.155 kg/s, and compared with the heat transfer characteristics of the plate heat exchanger under steady flow, it is found that the average increase in the heat transfer coefficient during the transition to the pulsating mode was 20%.
Бесплатно
Experimental study on unidirectional flow characteristics of flow diode
Статья научная
Flow diode is a kind of control fluid one-way flow of components, it has many advantages, such as simple structure, no rotating parts, no need for external control, power, high reliability, in the medical industry, nuclear industry, petrochemical industry, flow diode has a wide range of applications. By studying relevant literature, combined with the actual situation, based on the experimental study method, using air pump, pressure regulator, 3 d printers and other laboratory equipment, by changing the pump seal the air inlet, simulation of different flow diode under different conditions make the fluid flow through, will pump displacement into displacement, record each air inlet in unit time displacement, and then compared these data, the flow is obtained by carefully analyzing the flow characteristics of diode and the relationship between the fluid flow characteristics diode, it is concluded that: the displacement increases with increase of voltage; when the aperture changes, the flow diode will produce important changes; unstable flow characteristics of variable diameter flow diode.
Бесплатно
Статья научная
The article is devoted to the determination of the optimal parameters of a dielectric fluid as an impregnant in power capacitors. The optimal parameters for the synthesis of the ester are found on the basis of a not clear Mamdani model. The model providing optimization of the chemical process is offered and on the basis of statistical data, the algorithm of training of the fuzzy model is developed. The goal was solved with fuzzy data and a regression model of the three-stage process was obtained. Optimization was carried out and optimum parameters were found. Based on the statistical data, a fuzzy Mamdani model was compiled.
Бесплатно
Hadrian X - автономная роботизированная система для кладки кирпича
Статья обзорная
Рассматривается разработка инновационной системы для автономной кладки кирпича Hadrian X от компании Fastbrick Robotics, которая позволяет выстраивать дома из кирпича в автоматическом режиме без участия человека. Рассмотрены преимущества и недостатки данной разработки, а также области применения и перспективы развития в строительной области. Выявлены направления развития и совершенствования данной системы. Является лучшим способом строить типовое недорогое жилье за очень короткие сроки.
Бесплатно
High power led fish collector heat sink
Статья научная
High-power LED fish collector lamps are small in size and work with high heat flow density, LED chips emit more and more heat, and heat dissipation problems have gradually become a bottleneck limiting the development of LED. In this paper, for a typical power LED, it mainly discusses the LED packaging technology, the heat sink structure and characteristics of the impact on the heat dissipation conditions.
Бесплатно
Hot water heating circuit with impulse cavitator
Статья научная
An effective method of multifactorial influence on a liquid is cavitation, which leads to a change in the physicochemical characteristics of the liquid, its activation and heating. One of the devices, the principle of which is based on cavitation, is a cavitation heat generator. At present, the production of these units has been mastered by many manufacturers, and they appear in large numbers on the world market. Among the numerous designs of cavitation heat generators, a worthy place belongs to jet ones, which have the lowest pressure drop, but their efficiency is relatively low (from 20% to 40%) and does not meet modern requirements. The purpose of this work is to increase the efficiency of water heating in a cavitation heat generator based on the use of a pulsed mode of its operation. To achieve this goal, the following tasks were identified in the work: to develop a laboratory sample of a flow-pulse cavitator; to develop a diagram of a laboratory setup and a cavitator design; conduct hydraulic and thermal tests of the cavitator prototype, obtain the results and evaluate their effectiveness. Thus, the successful implementation of the goal of this work may encourage many industrial enterprises and households to abandon traditional heat supply systems and switch to modern sources of thermal energy, namely jet cavitation heat generators with a pulsed cavitator.
Бесплатно
How to learn and control effective hybrid cars
Краткое сообщение
The article deals with the history of hybrid cars, their types, running principle, parts, characters, advantages and negative features. Hybrid cars combine the efficient features of an electric motor and an internal combustion engine, and the use of hybrid cars in Azerbaijan, as in other countries, is satisfactory.
Бесплатно
Hydrodynamics of Absorption Bubbling Apparatus
Статья научная
The article proposes an improved design of the energy-saving, compact absorption bubbling apparatus, which cleans the particles and gas mixtures in the exhaust gases of industrial enterprises, has a high absorption efficiency. As a result of theoretical research, an equation has been proposed that calculates the value of the height of the gas cushion “h”, which provides equal distribution of purified gas to the mixing sections of the apparatus and operation in a stable hydrodynamic mode. As a result, depending on this value, it is possible to calculate the gas velocities and the gas consumption supplied to the apparatus.
Бесплатно
IPtables для обеспечения безопасности информационных сетей на базе Linux
Статья научная
В статье рассмотрены основные компоненты информационной безопасности: конфиденциальность, целостность и доступность. Пароли, шифрование, аутентификация и защита от проникновения - это методы, предназначенные для обеспечения конфиденциальности. Целостность означает поддержание данных в исходном состоянии и предотвращение их изменения: случайного или злонамеренного. Под обеспечением доступности информации понимают соответствие сетевых и вычислительных ресурсов ожидаемому объему доступа к данным и реализацию политики резервного копирования для целей аварийного восстановления. Для обеспечения безопасности информационных сетей на базе RedOS наилучшим образом показала себя утилита iptables, используемая для настройки брандмауэра ядра Linux. Несмотря на то, что на первый взгляд реализация IP-маршрутизации в Linux может выглядеть довольно сложной, на практике наиболее распространенные варианты использования (NAT и/или базовый брандмауэр Интернета) значительно проще реализуются. Iptables - это пользовательская утилита, позволяющая работать цепочками/правилами. В статье подробно рассмотрены принципы работы iptables, приведено подробное описание таблиц nat, mangle, filter, raw и цепочек. Таблица nat используется для трансляции сетевых адресов, mangle применяется для искажения пакетов, filter дает возможность выполнять фильтрацию пакетов, raw и ее цепочки используются перед любыми другими таблицами в netfilter. Цепочка input применяется для обработки входящих пакетов и подключений, forward - для проходящих пакетов, output - для исходящих пакетов. Показано, что для обеспечения безопасности функционирования компьютерных классов и всей сетевой инфраструктуры в целом, достаточно только двух таблиц: filter и nat. Другие таблицы предназначены для сложных конфигураций, включающих несколько маршрутизаторов и решений по маршрутизации. Приведены результаты использования iptables на основе опыта администрирования информационных сетей на базе RedOS в федеральном государственном бюджетном образовательном учреждении высшего образования «ПГУТИ».
Бесплатно
