№ 133(9), November, 2017
Public date: 30.11.2017
Archive of journal: Articles count 94, 254 kb
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Description
The influence of auto-displacement in a resonancetunnel diode (RTD) on the dynamic range of amplifiers on these diodes is considered in the article. The amplification at resonance frequency is considered and the influence of higher harmonics is not taken into account, since they do not create a significant voltage drop at the nonlinear resistance of the diode. It is assumed that the gain will be sufficiently large, and then the nature of the dependence of the gain factors on the degree of regeneration will be the same for amplifiers "per pass" and "reflection". This allows us to consider the problem for both types of amplifiers on the RTD. The types of amplitude characteristics , which are possible for the RTD amplifier, are considered. The dependences of the parameter determining the dynamic range of the amplifier on the position of the operating point for several values of the product of the resistance on the direct current of the supply circuit are calculated for the value of the modulus of the maximum negative conductivity of the tunnel gap RG max. For each value of RG max for given parameters, you can determine the position of the operating point, which provides the specified amplifier mode. Dependences of the value of the dynamic range are constructed with allowance for auto-displacement and in the absence of auto-displacement for two values of the degree of regeneration. Taking into account autosplacement, two possible types of amplitude characteristics and boundaries of their existence were revealed. For these two types of amplitude characteristics, expressions were obtained that determine the dynamic range of the amplifier
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Description
The work is done in scientific and practical directions for minimization of power losses in transmission of electricity to local distribution networks between the actors of the energy (producers and consumers) of energy-saving technologies focused on technological activities such as modernization and reconstruction of networks. Quite often in various circuits of power systems, it is advisable to transfer energy and its power through intermediate (transit) nodes. Structural changes in the electricity sector, at present, are mainly associated with the introduction of market relations between the subjects of energy exchange; therefore, in this work special attention is paid to the problem of calculating the power losses, as it is nonlinearly dependent on the power at the nodes and branches of a network. It should be noted that the nodes in problems transit capacity could be both sources and consumers. The latter necessitated the need for search of possible ways to reduce transportation losses of energy due to both the improvement and optimization of distribution networks and through the use of intermediate transit nodes. It follows that the transportation problem in this formulation is more General and expands the possibilities of optimization of power losses for the local subsystems of the energy clusters. The work is composed of the transport matrix for solving problems transit capacity, where the algorithm taking into account the distinctive features of which consist in the use of continuous numbering of sources and consumers in the matrix, and any node can be a transit country. The transit capacity ii-th node Zii=0, and the dimension of the matrix in contrast to the previously considered tasks has (n+m) (n+m) and it remains square as all the transport problems of linear programming. Transit variables Xii are included in the solution of the problem with a minus sign, and all transit variables are considered basic. From the above example in the work of a number of branches of a network is minimal, which significantly reduces the cost of building and maintaining the network, and the solver minimizes the power loss between the subjects of energy exchange and, as a result to savings from the standpoint of cost of construction of the network and the management of overflows of energy in it
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THE METHOD OF CALCULATION OF FILTERS FOR STATIC CONVERTERS OF ELECTRIC POWER
Description
One of the important issues in the design of static converters of electric power, i.e. rectifiers and inverters, is to calculate the parameters of the output and the input filters. Output filters are designed to improve the quality of output voltage of inverters, and input filters are created to reduce ripple of the input voltage of the converter that occur when commuting power semiconductor devices, and smoothing fluctuations of the current consumed from the power supply. The complexity of analytical description of the harmonic composition of the output and the input of the voltage rectifiers and inverters makes it difficult to develop some accurate methods for calculating the parameters of their filters. At the same time, considering the discreteness of the number of possible parameters of real elements of the filter, the practical value of such techniques with a high analysis accuracy of the harmonic components is negligible. In this article, we suggest the technique of the simplified calculation of output and input filters for passive LC filters rectifiers and inverters. At the same time, the practice of mathematical modeling and design of transducers has shown that the calculations of the filter parameters for rectifiers and inverters are not significantly different from each other. Therefore, the analytical expressions for calculation of the filter parameters of rectifier used ripple coefficient, and if necessary the calculation of the filters of the inverter, instead of the pulse number in the formula can be substituted with the value of the harmonic; in addition, we have also taken into account the value of the load power factor
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Description
Fruits are an important part of the diet of humans and many animals. In case of an improperly organized process of storing of fruits, the loss of mass and decrease of quality can be substantial. This makes relevant the research, aimed at enhancing existing and developing new technologies of fruits storing. In this article, the results of the investigation of influence of complex treatment of fruits with electromagnetic fields of extremely low frequency (EMF ELF) and а biopreparation on the change of microbial contamination of their surface and on the loss of mass in the process of long-term storage are revealed. Apples of the Idared variety and pears of the Conference variety were the objects of research. The change of microbial contamination of the surface of fruits, undergone a few types of pre-treatment (EMP ELF, bio-preparation “Vitaplan”, complex treatment “EMP ELF + the biopreparation” and no special treatment), after storing during 7 months in case of pears and 8 months in case of apples is shown in the article. It was found, that the greatest decrease of content of microorganisms on the fruits’ surface is achieved as a result of the complex treatment, combining the treatment with EMP ELF and an aqueous solution of the “Vitaplan” bio-preparation. The effective parameters of such a treatment for apples and pears are represented
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METHODOLOGY OF MODELING SOCIAL SYSTEMS FOR CONFLICT ANALYSIS AND CONTROL
Description
This article provides results of studying the world achievements in modeling social systems in the aspects of personality, group, and social institute (e.g. the state and army). Through prism of conflict, we review research methodology for modeling social identity, social navigation, geopolitical processes, and command and control systems of the enemy. We discuss four agent-based models of social identity: SCIPR, MetaContrast, PS-I, and SILAS. We examine Spence model for modeling social navigation. Basic principles for modeling relations between the states are considered using ontology approach. The presented model allows systemic analysis of various micro- (intrastate) and macrolevel (external) variables and relations between them. Modeling command and control system of the enemy is implemented as a part of an automated decision support system that tackles the problems of enemy structure identification as well as classification of objects and relations within the structures. The object of study are approaches, methods and models for representation and analysis of group interaction. The subject of study are processes of agent self-identification and interaction, formal and informal organizations, the states and public institutes as well as processes and principles for group formation and mechanisms for behavior control. Research methodology: social network analysis, ontology approach, theory of graphs and hypergraphs, multiagent systems
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A COMPUTER AUTOMATED SYSTEM AS A WAY TO IMPROVE THE EFFICIENCY OF REPAIR FACILITIES
Description
During an era of rapid development of society and all areas of its activity, special attention should be paid to a condition of the objects considerably simplifying humans’ life. The car, which began to be an integral part of each family, is among such objects. But sometimes, the car can get into accident and then some malfunctions appear. For their elimination, motorists address to the specialized organizations for car repairs. The article is devoted to introduction of information technologies to the sphere of rescue and recovery operations of a body of the car. Today, a necessary condition of advance in the sphere of information technologies is widespread introduction of standards and technologies of the information systems used both for hardware, and for software products. In this study, the efficiency of application of the complex of hardware (CH) by means of which achievement of improvement of quality of rescue and recovery operations, through a possibility of comparison of the damaged detail with its factory model and a possibility of quality check of the end result will be considered. The set of methods and techniques of the organization of information processes in the production systems allowing carrying out the choice and use of necessary information technical solution for synthesis of knowledge of a production situation makes contents of the concept of formation of information resource of a control system of the knowledge-intensive production
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THE PROJECTS SUCCESS ISSUES IN SYSTEM INTEGRATION
Description
The article explores the distinctive features of project management in the field of information technologies in general and in system integration in particular. We have analyzed and explored the success of project management cases in global practice of project management in information technologies, explored the criteria of success in projects and its evolution throughout the history. The article also investigates the main problems and risks in project realization and identifies the factors, causing the negative effect on project management. We have explored the interconnections between the identified problems and the lifecycle of the project and the fundamental features of the project management. We have also paid attention to the role of the project manager and the importance of his contribution to the project. We have worked out a set of measures entitled to minimize the identified risks and to increase the success of project management in information technologies and system integration
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SUPPLYING THE GREENHOUSES WITH POWER BY THE USE OF ASYNCHRONOUS GENERATORS
Description
Due to the recommendation of the World Health Organization, the standard rate of vegetables consumption for a person per year is 130-150 kg, including up to 15 kg of fresh production during the off-season. To meet these standards in Russia, the construction of greenhouses and greenhouse complexes was sped up. To cultivate the bulk of vegetables in the conditions of protected soil we have mostly used winter greenhouses. At the same time, in terms of the climatic conditions, the main production costs are accounted for energy carriers (up to 60 – 70%). The main consumers of energy in greenhouses are plants’ lighting and creation of the required temperature conditions for plants and soil. Annual increase of rates for energy carriers affects the cost of the greenhouses’ production. To increase the energy efficiency and independence in greenhouse complexes, it is proposed to use installations based on gas reciprocating units (GRU) for the production of two types of energy – electric and thermal. Such installations can run on the natural gas and other types of fuel. The drawback of existing installations is that they are mainly produced abroad or consist of the foreign components. As an alternative, we offer new technical solutions, which were developed and patented in the Russian Federation. What makes these solutions original is that asynchronous generators in the installations are used with various control schemes
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Description
Now in different branches of the industry there is a need for the new equipment and mechanisms with the seized characteristics. Special requirements are shown to energetic and mass-dimensional indices of systems of electric drives as one of the main components of such devices. Mass-dimensional and energetic indices due to constructional features and the used management system will allow improving use of special or controlled asynchronous cascade systems of an electric actuator of cylindrical construction. One of the main difficulties is simulation and design of special systems of the electric drive. In this article, a new approach to determination of magnetic model parameters of the stator of a component of the controlled asynchronous cascade electrical drive of cylindrical construction is offered
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Description
The transportation process plays an important role in the delivery of agricultural products to the consumer. On how well the fruits are preserved, their grade will depend, and, consequently, the price of them. It is known, that the annual damage from losses of agricultural products in the agro-industrial complex amounts to 8 billion rubles, according to various estimates. A large number of different factors affect the safety of fruits during transportation: temperature, humidity, smoothness of the vehicle, type of container, etc. The more factors will have a negative impact on fruit and vegetable products, the more losses will ultimately be. The appearance of dents and abrasions on the fruits gives rise to the formation of foci of rot, leading to damage to the transported products, and, as a consequence, reducing the grade. In order to reduce the losses of fruit and vegetable products in the process of transportation, the USSR and the Russian Federation have been and are working on the creation of containers and ways of transporting pomegranates. All of them, according to the authors, are able to reduce the dynamic loads that arise during the transportation process and have a negative impact on the transported products. However, due to various circumstances in commercial gardening all these developments have not been extended
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