scholarly journals FEATURES OF DESIGNING OF BISTABLE ELECTROMAGNETIC LATCHING RELAYS

Author(s):  
Evgeniy G. Vasilyev ◽  
Ivan P. Ivanov ◽  
Oleg N. Mitrofanov ◽  
Dmitriy V. Samuilov ◽  
Gennadiy P. Svintsov

Bistable relays are widely used in both general and special purpose engineering. Such relays are subdivided according to the construction principle into two groups: bistable electromagnetic polarized relays and bistable electromagnetic latching relays. In the technical literature, there is practically no information on the design of the relay of the second group. This article highlights general issues of their design using the example of high-current relays of the DP-1 series for rated currents from 25 to 100 A, which have been used for a long time in autonomous power supply systems for military equipment. The descriptions of the distinctive features of the relay construction and the principle of its operation are given. The kinematic schemes of the main mechanism of the electromagnetic and contact systems are considered. The example of constructing the opposing characteristics of the relay is shown. The paper provides the replacement scheme for calculating of magnetic system on improved method of sections and assumptions, characteristic of the given relay construction.

2021 ◽  
Vol 13 (15) ◽  
pp. 8628
Author(s):  
Emília Duľová Spišáková ◽  
Barbora Gontkovičová ◽  
Emil Spišák

Research and development have been of interest to the European Union for a long time. This topic is also underlined in economic reform agendas and plans that have the form of strategies with clearly set targets. The article deals with the issue of financing R&D activities from the perspective of the share of expenditure to GDP, the total amount of funds spent on R&D, the share of expenditure per capita, and the structure of expenditure. The aim is to analyze and compare development in the field of R&D financing in selected countries of the European Union with emphasis on achieving the Europe 2020 target and to point out the expected development of the indicator for the first years of the validity of the 2030 Agenda for Sustainable Development. During the processing of the article, mathematical and statistical methods (regression and correlation analysis) were used in addition to standard logic methods intended for processing data and drawing conclusions (synthesis, induction). The final evaluates the achievement of the target in the field of R&D financing in accordance with the target of the Europe 2020 strategy and, using regression, predicts the development of the given indicator for coming years.


Author(s):  
Hikmat Hamid oglu Asadov ◽  
Sima Ajdar gizi Askerova

Pollution of sea waters is one of major attributes of coastal industrial centers and the norming of such emissions is one of major countermeasures. The assimilation capacity of sea waters is a major factor relevant at norming and planning of outflows into sea waters. At present time the synoptical method has been developed, which doesn’t require carrying out long time and repeated observing of the level of pollution of sea waters. This method has formed the basis for developing the integrated synoptical method for calculating sea water assimilation capacity. The suggested method provides for division of the sea waters into separated homogenous water masses. The aim of the study is to develop an inverse integrated synoptical method allowing synthesizing of such an optimum order for loading separate water masses with pollutants upon, at which the calculated total value of assimilation capacity would reach its maximum. The article shows the possibility of utilization of known synoptical method for determining assimilation capacity of sea waters in the inverse order, i.e. for calculating the maximum value of pollutant put into the fixed zone of sea waters, upon a condition of reaching the given amount of assimilation capacity and absence of essential negative effect on ecosystem. The task of calculating an optimum regime function of discrete type, upon which the integrated value of assimilation capacity would reach the maximum value, has been formulated. The solution of analogue equivalent of the formed optimization task is carried out using the Euler equation for a non-conditional variation optimization task, taking into account the accepted limitation condition. The recommendations on optimum loading of different sea water zones with determined type of pollutant have been given.


Vestnik MGSU ◽  
2019 ◽  
pp. 621-633 ◽  
Author(s):  
Tatyana A. Rafalskaya ◽  
Valery Ya. Rudyak

Introduction. Being used in various industries, heat exchangers most often work under conditions of variable coolant flows and temperatures. At the same time, the existing theories of calculating the heat exchanger operation modes are based on the use of constant unitless parameters at any operation mode. Taking into account the effect of coolant rates on the heat transfer coefficient of the heat exchangers, the given relations are bound to specific types of heat exchangers and can only be used at constant coolant temperatures. The purpose of this study is to obtain expressions for determining the effect of coolant flow rates on the variable heat exchanger parameter. Materials and methods. The main variable operation modes for water-to-water heat exchangers used in heat supply systems are determined. Using simulation in the PTC Mathcad software, dependencies describing the change in the heat exchanger parameter for all the considered variable operation modes are defined. This made it possible to obtain a general formula for the change in the heat exchanger parameter for varying coolant flow rates. Coefficients in this formula take into consideration the effect of coolant temperatures, which cannot be known when calculating variable conditions, especially when the interconnected heat exchangers are operating. Results. To test applicability of the existing relations describing the change in the heat exchanger parameter and of obtained formula, a large number of heat exchangers is calculated at variable operation modes. Comparison with the simulation results shows that the correlations of heat exchanger theories work well at the mode with constant coolant temperatures only, while their use at other operation modes can lead to large calculation errors. Conclusions. The obtained formula allows finding the effect of coolant flow rates on the variable heat exchanger parameter. The formula can be used to predict the operation modes of large systems including a large number of various-type heat exchangers.


2021 ◽  
Vol 297 ◽  
pp. 01071
Author(s):  
Sifi Fatima-Zahrae ◽  
Sabbar Wafae ◽  
El Mzabi Amal

Sentiment classification is one of the hottest research areas among the Natural Language Processing (NLP) topics. While it aims to detect sentiment polarity and classification of the given opinion, requires a large number of aspect extractions. However, extracting aspect takes human effort and long time. To reduce this, Latent Dirichlet Allocation (LDA) method have come out recently to deal with this issue.In this paper, an efficient preprocessing method for sentiment classification is presented and will be used for analyzing user’s comments on Twitter social network. For this purpose, different text preprocessing techniques have been used on the dataset to achieve an acceptable standard text. Latent Dirichlet Allocation has been applied on the obtained data after this fast and accurate preprocessing phase. The implementation of different sentiment analysis methods and the results of these implementations have been compared and evaluated. The experimental results show that the combined uses of the preprocessing method of this paper and Latent Dirichlet Allocation have an acceptable results compared to other basic methods.


2018 ◽  
Vol 245 ◽  
pp. 13001 ◽  
Author(s):  
Mikhail Doronin ◽  
George Greshnyakov ◽  
Nikolay Korovkin

Cables with high current capacity are used in power devices, including special-purpose ones operating in impulse modes. It is important to ensure low inductance of such cables, because these type cable products are often used as connecting products. This article discusses the problems that arise in the design and manufacture of special low-inductance impulse cables (SLIC) for power supply and protection of the superconducting magnetic system of the ITER reactor (France), the distinguishing features of which are the optimum ratio of insulation thickness and throughput at low inductance.


Author(s):  

System engineering laws of big cities’ centralized water supply functioning and development have been stated in a structural form. This enables to define strategy of scientific research and updating of enginnering infrastructures of the municipal water sector. The given approach is applicable for substantiation of priority directions in the process of development and adoption of technical solutions on providing environmental safety for drinking water supply systems.


2020 ◽  
Vol 1 (191) ◽  
pp. 150-154
Author(s):  
Olena Synyukova ◽  
◽  
Oleh Chepok ◽  

The so-called tasks with parameters for a long time now have become an integral part as of the every to some extent profound course of algebra or of algebra and the beginnings of cultures at the institutions of general secondary education, as of the corresponding tasks of the State Final Attestation in Mathematics and the External independent assessment in mathematics. And it isn’t accidental because in the most often cases the solution of the task with a parameter turns for the student into a small investigation by his own. The realization of such investigation favors the formation of the creative practical-oriented personality. Simultaneously we must state that, despite of the existence of a lot of the high scientific and methodical level created corresponding training books, it is difficult just now to find in the methodical literature the clear answers to the natural questions of what is meant on the whole by the task with parameter (or with parameters) and its solution. At the same time, in the courses of geometry of the institutions of general secondary education to the tasks with parameters it is given next to nothing consideration. But in fact such tasks in the courses are present, their importance for the proper construction of the courses can be exaggerated. In the paper the problems of what must be understand by the task with the parameter or with the parameters and by its solution are analyzed. The essence, the part and the place of the tasks with parameters in the geometry courses of institutions of general secondary education are elucidated. Euclidean geometry as an axiomatic theory investigates the sets that in their overwhelming majority represent by themselves the mathematical abstructions of the spatial forms of the surrounding, some relations between such set and quantities that characterize such sets and relations. In the contrast to the courses of algebra, in the geometrical courses the part of parameters may be played by all of the three mentioned components. Geometrical figures can change by the size and by the form. Changing by the size bring us to the concept of the scalar quantity. Changing by the form are considered in the tasks of paving and, for example, in the tasks of finding the amount and the types of symmetries of geometrical figure in dependence of its form. The part of the parameter-relation can be played by different variants of mutual displacement of the given figures in Euclidean plane or in Euclidean space. According to their content, different geometrical tasks with parameters are considered in the work. The task of the existence of geometrical figures, the tasks, conserning the character of some geometrical places of points, the tasks of tracing with the help of a compass and a ruler are among them.


2021 ◽  
Vol 8 ◽  
Author(s):  
Radu Mariescu-Istodor ◽  
Pasi Fränti

The scalability of traveling salesperson problem (TSP) algorithms for handling large-scale problem instances has been an open problem for a long time. We arranged a so-called Santa Claus challenge and invited people to submit their algorithms to solve a TSP problem instance that is larger than 1 M nodes given only 1 h of computing time. In this article, we analyze the results and show which design choices are decisive in providing the best solution to the problem with the given constraints. There were three valid submissions, all based on local search, including k-opt up to k = 5. The most important design choice turned out to be the localization of the operator using a neighborhood graph. The divide-and-merge strategy suffers a 2% loss of quality. However, via parallelization, the result can be obtained within less than 2 min, which can make a key difference in real-life applications.


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