Технические науки. Рубрика в журнале - Бюллетень науки и практики
Memory leaks in SPA: prevention, detection, and remediation methods
Статья научная
This article addresses the issue of memory leaks in modern single-page applications (SPAs). By investigating the causes of leaks associated with dynamic content updates, active interaction with the document object model (DOM) interface, and asynchronous operations, developers gain insights into avoiding the excessive accumulation of unused objects in memory. The article discusses methods for preventing and addressing leaks, including the use of weak references, component state management, and optimizing asynchronous requests. It also emphasizes the importance of using monitoring tools, such as Chrome DevTools, and integrating automated testing into the continuous integration (CI) and continuous delivery (CD) process. The article offers a comprehensive approach for efficient memory management and preventing performance issues in SPA applications.
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MgH2 insights used for hydrogen storage and catalysis: preparation, characterization and mechanism
Статья научная
Magnesium is a rich element on earth, with high reversible, cycle stability and antitoxicity, low cost, and high-volume hydrogen capacity, its theoretical hydrogen storage capacity up to 7.6 wt %. Magnesium-based hydrogen storage materials are considered as one of the most promising hydrogen storage media. However, due to its high thermodynamic stability and slow hydrogen adsorption kinetics, the high adsorption temperature and long adsorption time limit its practical application. In order to overcome the thermodynamic and kinetic obstacles of magnesium-based hydrogen storage materials in practical application and improve the hydrogen storage performance of MgH2, catalytic modification is a very effective method at present. This review summarizes the preparation methods, characterization methods and reaction basis of various catalysts modified by MgH2. Finally, we analyze the development trend of various catalysts in the future, as well as the application prospects.
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Model of a heat exchanger air heating booster
Статья научная
To solve the problem of energy crisis in today’s world, energy conservation is more and more get the attention of people, heat exchanger occupies an important place in the field of energy saving, however, because of the heat exchanger is a traditional energy-intensive heavy industry, one of the most widely used equipment in it as preheating, mainly in the process of waste heat recovery, refrigeration equipment, made outstanding contributions to energy saving. In this paper, spiral plate heat exchanger as the research object, select the established model, through the analysis of the existing heat transfer enhancement theory, combined with the classical optimization algorithm genetic algorithm spiral plate heat exchanger programming optimization, through iterative calculation to get the optimal spiral plate heat exchanger structure parameters. On this basis, based on the theory of dissipative, puts forward a new physical volume of fire, and established a new heat exchanger performance evaluation standard unit total cost model of heat transfer, and the objective function, analyzes the structural parameters in the spiral plate heat exchanger (cold and hot fluid flow, heat exchanger, plate spacing) and their relationship. Because the total cost per unit heat transfer not only considers the thermodynamic performance of the heat exchanger but also the economic feasibility of the heat exchanger. Finally, combined with the simulation calculation of the performance of the heat exchanger before and after optimization structure parameters, further analysis of its internal flow. The research in this paper provides a theoretical basis for the design, structure optimization and performance prediction of spiral plate heat exchanger.
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Model of a microchannel heat exchanger of a supercharger for heating water
Статья научная
The subject of the research is a model of a microchannel heat exchanger of a supercharger for heating water. The purpose of study is to simulate the heating effect of microchannel heat exchangers for heating water and to evaluate their effectiveness in practice. Research methods: comparison, synthesis, modeling, description, experimentation, graphical analysis. As a result of the study, the prerequisites for the energy conversion of the microchannel heat exchanger, the heating unit, the energy conversion unit, and the biofuel storage unit were considered and put together. The degree of implementation is complete. Efficiency of development - in order to enhance energy use and reduce losses in energy use, thereby protecting the environment and saving energy.
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Modeling of the organic Rankine cycle based on the theory of energy chains
Статья научная
This paper examines an experimental setup of an organic Rankine cycle and proposes a method for describing it using differential equations. The aim of the work is to obtain approximate values of the setup's characteristics before conducting the experiment. The constructive scheme of the experimental device and its operating principle are described in detail. The power circuit of the setup is composed, and complex impedance, frequency function, amplitude-frequency, and phase-frequency characteristics are obtained based on the mathematical transformation of the circuit. The frequency response of the circuit is constructed. As a result of the calculations, the amplitude-frequency and phase-frequency characteristics are obtained, and graphs are plotted based on them. Conclusions are drawn about the dependence of the characteristics on the change in parameters, and the shape of the graphs is explained. The results of the work can be used to predict the behavior of the experimental setup of the organic Rankine cycle and optimize its parameters before conducting physical experiments.
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New method of using mobile robots for moving cargo in warehouse
Статья научная
The new patented method for moving cargo in warehouse is proposed in this article. According to the new method, movement of cargo from the storage area to another warehouse area is carried out by throwing the cargo by the first mobile robot and catching the thrown cargo on fly by the second mobile robot. The parameters of the calculated trajectory of movement, in the free flight phase, of the center of mass of the cargo to be thrown are calculated by numerical methods for solving the Cauchy problem for a system of ordinary differential equations, and by the shooting method for boundary value problems of a system of ordinary differential equations. The first mobile robot throws the cargo at the specified angle to the horizon with the specified initial velocity, at the specified moment of time. In order to catch the thrown cargo on fly by the second mobile robot, the parallel algorithm A1-A2 for catching a thrown cargo on fly by the second mobile robot was created. The method allows the first mobile robot to throw cargoes for large distances, and the created algorithms allow the second mobile robot to catch reliably the thrown cargoes on fly. The proposed method for moving cargo is superior in economic efficiency and reliability to the other methods for moving cargo by implementing tossing of inventory items by robots.
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New wireless technology for data transmission in chemical systems
Статья научная
New type of wireless computer network in chemical systems is presented in this article. This wireless network uses chemical system as physical media for data transmission, instead of environment. Thus, represented wireless network differs substantially from molecular communication networks and wireless networks covered by IEEE standards, such as radio frequency based wireless networks. This new wireless technology can be used not only in chemical industry for continuous controlling chemical processes in chemical reactions zones but also for medical purposes, and as a new type of wireless body area computer network.
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Статья научная
The spatial distribution of heavy oils and natural bitumen’s depending on their reserves is analyzed. It is shown that due to the deterioration of the structure of the reserve in the direction of increasing the share of hard-to-recover oils, the role of heavy oils and natural bitumen’s in the overall hydrocarbon balance increases. Analysis of reserves showed that most of their world reserves are concentrated in Canada, Venezuela, and Russia. The results of studies of the distribution patterns of heavy oils and natural bitumen’s can be used in improving methods of field search and in solving other problems of the oil industry.
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Numerical simulation of the effect of air velocity on fin heat dissipation
Статья научная
Fin has a good effect in strengthening heat dissipation, and the structure is simple, and it has been widely used in civil and industrial applications, such as radiators, automobile engine heat dissipation, air conditioning internal and external units, computer radiators and air preheaters of power station boilers. Based on the CFD numerical simulation method, the temperature change of the fin under different flow velocities is simulated. Result surface: When the calculation time is 100 seconds, when the air velocity is 0.5 m/s and 1 m/s, the heat dissipation of the fin is about 3.1℃ and 4.6℃ increasing than that at 0 m/s.
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Статья научная
Baffle heat exchanger is widely used in various production activities because of its simple design and strong adaptability, so the structural optimization of baffle heat exchanger is of great significance to engineering practice. COMSOL software was used to simulate the shell-and-tube heat exchanger with baffles. By comparing and analyzing the simulation results, we find that the temperature field and pressure field of baffle plate are distributed evenly; The existence of baffles leads to the transverse flow of air, which increases the heat exchange area. Another advantage of using baffles is that vibration due to fluid flow can be reduced.
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Numerical simulation research on cavitation flow of different fuels in diesel engine injectors
Статья научная
With the increasingly stringent requirements of diesel engine fuel consumption and pollutant emission, higher requirements are put forward for the performance of diesel engine fuel injection systems. Cavitation flow in diesel fuel injectors is an extremely important factor affecting spray characteristics. In this study, the occurrence of cavitation in the fuel injector nozzle and its impact on mass flow rate and vapor fraction at the outlet of the fuel injection hole are studied numerically for various fuels such as diesel, gasoline, ethanol and methanol. The results show that the mass flow rate of diesel is the highest and that of gasoline is the lowest. Methanol and gasoline have the highest vapor content, followed by ethanol, and then diesel with the lowest vapor phase. For mass flow, the mass flow is inversely proportional to the viscosity of the fuel, and for cavitation, the amount cavitation is inversely related to the viscosity of the fuel. This agrees with many researchers’ findings.
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Статья научная
The accommodation of renewable energy is driving the development of energy storage technology, and shared energy storage has gained widespread attention because of its decentralized nature. In the optimal scheduling of shared energy storage, the problem of benefit distribution among multiple subjects is faced, so a shared energy storage plant operation optimization method based on Nash bargaining theory is proposed. The article constructs a joint model of shared energy storage plants and industrial users, establishes the cooperative operation model of each operator based on Nash bargaining theory, equates this nonconvex nonlinear problem into two subproblems of system revenue maximization and power transaction payment bargaining according to the mean value inequality, and uses the alternating direction multiplier method to solve them in a distributed manner. The algorithm selects three typical industrial users to participate in the joint system of shared energy storage, and through comparative analysis before and after cooperative bargaining, it is concluded that the proposed optimization method can effectively improve the benefits of each subject, while promoting the accommodation of new energy.
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Optimal design of heating boilers
Статья научная
Instead of a regular flywheel, it is possible to install a lightweight, with a variable moment of inertia on the electric unit, which will accelerate faster, which means it is faster to enter the mode of the rated frequency of the generator output voltage. In a mode close to the nominal speed of rotation, the moment of inertia will increase sharply, which will allow more mechanical energy storage, which will not allow to slow down the speed of the internal combustion engine, so it is better to damp (smooth out) the low-frequency external disturbances from the side of the electrical network.
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Статья научная
The integrated energy system (IES) is an effective way to achieve the “carbon neutrality and emission peak” goal. In order to further explore the role of the adjustable potential of demand side on carbon emission reduction, an optimized operation model of IES considering the demand response under the carbon trading mechanism is proposed. Firstly, according to the characteristics of load response, the demand response is divided into two types: price-type and substitution-type. The price-type demand response model is established on the basis of price elasticity matrix, and the substitution-type demand response model is constructed by considering the conversion of electricity and heat. Secondly, base-line method is used to allocate free carbon emission quota for the system and considering the actual carbon emissions of gas turbine and gas boiler, a carbon trading mechanism for the IES is constructed. Finally, a low-carbon optimal operation model of IES is established, whose objective is to minimize the sum cost of energy purchase, cost of carbon transaction and cost of IES operation and maintenance. The effectiveness of the proposed model is verified through four typical scenarios. By analyzing the sensitivity of demand response, heat distribution ratio of gas turbine and the operating state of the system under different carbon trading prices, it is found that reasonable allocation of price-type and substitution-type demand response and heat production ratio of gas turbine is beneficial to improve the operating economy of the system. Making reasonable carbon trading price can realize the coordination of system economy and low carbon.
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Optimal operation of integrated energy systems based on multi-energy complementarity
Статья научная
Complementary multi-energy operation is an inevitable trend in the development of integrated energy systems, and the construction of a fair and reasonable distribution method among multiple stakeholders is the key to realizing complementary multi-energy operation. Integrated energy systems have important applications for achieving sustainable energy development and building a green, low-carbon society, while the complex internal energy structures and equipment coupling relationships pose challenges for their operational optimization. Taking advantage of the interactive and complementary relationship between power and heat on both the supply and demand sides, energy storage devices are used on the supply side to realize the thermo-electrolytic coupling of the combined supply equipment and to enhance the multi-energy supply capacity of the system through each energy conversion device. On the demand side, load types are classified, and the elasticity of electrical loads and the diversity of system heating methods are used to construct a comprehensive energy demand response model with time shifting and curtailment responses of electrical loads and responses of heating load supply methods, and to propose a response compensation mechanism. On this basis, with the objective of minimizing the sum of system operation cost and response compensation cost, the mathematical model for optimal operation of integrated energy systems based on multi-energy complementarity is established, taking into account the equipment operation and dispatchable load resource constraints on both the supply and demand sides. Simulation results and comparative analyses based on arithmetic examples show that: synergistic optimization of both supply and demand, taking into account multi-energy complementarities, can effectively improve the flexibility and operational economy of the system.
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Статья научная
Combined with domestic and foreign literature, the research progress, key parameters and existing problems of flat-panel solar collectors are analyzed. On this basis, the thermal efficiency of flat-panel solar collectors is studied by means of experiments and numerical simulations. This paper introduces and analyzes the structural characteristics of flat-panel solar collectors. Based on the structural characteristics of flat-panel solar energy and research at home and abroad, the influence of the structural parameters of each flat-panel solar collector on the collector performance was studied. According to the heat transfer process and structural characteristics of the collector, the heat energy equation of the collector is established, and the calculation process of the heat loss of the collector is simplified according to the existing research, and the calculation of the heat loss coefficient is an empirical formula. In order to facilitate the experimental study, an efficiency factor and a heat transfer factor are introduced, and the temperature of the fluid at the inlet of the collector is used to replace the surface temperature of the heat-absorbing plate, which is difficult to measure. The calculation program is used to obtain the influence data of each key parameter of the collector on the thermal efficiency and use Origin to process the data to visualize the influence of each parameter on the thermal efficiency. On this basis, a variance analysis method is proposed to optimize the collector. Based on the PYTHON software, the calculation program is written according to the variance analysis method, and the key parameters that will greatly affect the instantaneous efficiency of the collector are combined in pairs, and the optimal collector parameter combination corresponding to the maximum instantaneous efficiency is studied. This research has a certain guiding effect on the utilization of solar energy.
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Optimizing the time costs of passenger transport of people with disabilities
Статья научная
The paper dwells on a mathematical model of the logistical system of transport services for persons with disabilities, and there have been analyzed factors that affect the time spent on their transportation. When developing methodology for optimizing the time costs of passenger transport of persons with disabilities, the following two basic transportation services have been taken into account: “Social Taxi”, which will transport only people with special health; b) vehicle system in combination with urban passenger transport, which will transport representatives of the group of people with restricted mobility together with all other passengers. The study found that in the case of insufficient accessibility to the required environment, by the increase in the demand of disabled people for transportation by “social taxi”, travel costs are increased that results in increasing total costs of the carrier. When determining the expenses of passengers, it is necessary to take into account the additional time, which the disabled persons need for boarding and alighting in buses at the stopping points, on average 2-3.5 minutes.
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Ordering and density amorphous phase of carbon-fiber polymer-matrix PTFE-composites
Статья научная
We studied the application of a mathematical model for calculating the X-ray density of a pure amorphous-crystalline polymer, taking into account the degree of ordering, crystallinity and deformation of a crystalline cell in the amorphous phase, to carbon-fiber PTFE-composites. By comparing the theoretical densities (based on the developed software) of PTFE+CF-composites system with the results of experimental densities and X-ray structural parameters, it was shown that the degree of ordering and density of the amorphous phase of the polymer-matrix PTFE-composites linearly decrease as the content of the carbon-fiber increases. The change in the degree of ordering of the amorphous phase when filler application can be considered as one of the mechanisms of formation of supramolecular structure of composite materials on the basis of amorphous-crystalline polymers.
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Organization of pulsating air flow through a heat exchanger
Статья научная
In recent years, the enhancement of heat transfer by pulsating flow has become a research hotspot. A great deal of work has been done in the past, with remarkable results, to achieve better heat transfer rates. How to improve the efficiency of heat exchanger is always a research topic. In this paper, pulsating air flow is formed by standard ventilation grille and electric actuator, and the pulsating air flow is guided through two-stage heat exchanger to study the influence of pulsating air flow on heat transfer efficiency. The experimental results show that the heat transfer efficiency can be improved by pulsating flow and the heat recovery efficiency can be reduced by increasing the flow rate of the heating medium.
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Overview of research on heat transfer technology for reinforcement of shell and tube heat exchanger
Статья обзорная
The progress made in recent years in the field of reinforced heat transfer technology of shell and tube heat exchangers in China and abroad is reviewed. The energy-saving means and results of improving the heat transfer efficiency of shell and tube heat exchangers are introduced from the experimental research and numerical simulation respectively, and the future research of shell and tube heat exchangers to strengthen the heat transfer technology is also foreseen.
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