Herald of Dagestan State Technical University. Technical Sciences最新文献_第10页

Modeling of regasification and recirculation processes during the transportation of liquefied natural gas 液化天然气运输过程中再气化和再循环过程的建模

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-05-08 DOI: 10.21822/2073-6185-2023-50-1-6-14

A. Baranov, E. Seredenko, T. A. Malysheva, Y. Kravchenko

引用次数: 0

To the issue of optimising the performance of a scroll compressor as part of a CO2 booster refrigerating machine in order to increase its efficiency 以优化涡旋压缩机作为CO2增压制冷机的一部分，以提高其效率的问题

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-05-08 DOI: 10.21822/2073-6185-2023-50-1-42-52

V. Pronin, A. Kovanov, V. Tsvetkov, E. N. Mikhailova, P. A. Belov

{"title":"To the issue of optimising the performance of a scroll compressor as part of a CO2 booster refrigerating machine in order to increase its efficiency","authors":"V. Pronin, A. Kovanov, V. Tsvetkov, E. N. Mikhailova, P. A. Belov","doi":"10.21822/2073-6185-2023-50-1-42-52","DOIUrl":"https://doi.org/10.21822/2073-6185-2023-50-1-42-52","url":null,"abstract":"Objective. With the decreasing use of refrigerants with a high global warming potential, increasing the efficiency of refrigeration machines using natural working fluids is a very urgent task. The CO2 booster refrigerant cycle may be optimal for the fields of commercial refrigeration, climate engineering and heat pumps, but needs to be adapted to regions with hot climates. The purpose of the study is also to systematize possible ways to improve the spiral technology, as a guarantee of increasing the efficiency of booster refrigeration machines.Method. Such solutions have already been tested by increasing the transcritical cycle efficiency through the use of an ejector and parallel compression. However, the use of a scroll compressor in the transcritical cycle may be a good alternative to these methods. This solution, a little bit improves technical and economic indexes of the refrigerating machine, in the most part reducing capital and operational costs. When considering the prospect of improving the efficiency of a booster system with scroll compressor, it is necessary to address the issue of compressor performance optimisation. An issue of this kind can be referred to improving the efficiency of the booster system, at the expense of the internal characteristics of the refrigeration machine.Result. Thus, in this paper, a conceptual approach is considered to solve this problem based on a system analysis of the interconnection of the compressor as the main energy-intensive element of a refrigeration machine.Conclusion. Development of conceptual model, allows to identify influence of various factors on scroll compressor operation and to build adequate mathematical model, to choose or develop necessary calculation methods.","PeriodicalId":202454,"journal":{"name":"Herald of Dagestan State Technical University. Technical Sciences","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127225986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Field studies of a thermoelectric system for thermal action on the anterior segment of the human eyeball 热电系统对人类眼球前段的热作用的现场研究

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-05-08 DOI: 10.21822/2073-6185-2023-50-1-15-23

O. V. Evdulov, I. Y. Aminova, G. I. Aminov, S. Gasanova, P. N. Surakatova

{"title":"Field studies of a thermoelectric system for thermal action on the anterior segment of the human eyeball","authors":"O. V. Evdulov, I. Y. Aminova, G. I. Aminov, S. Gasanova, P. N. Surakatova","doi":"10.21822/2073-6185-2023-50-1-15-23","DOIUrl":"https://doi.org/10.21822/2073-6185-2023-50-1-15-23","url":null,"abstract":"Objective. The aim of the study is to develop the design of a thermoelectric system (TPS) for thermal action on the anterior segment of the human eyeball, as well as to conduct its field studies.Method. The study is based on the methods of thermodynamic analysis, natural and computational modeling of processes and life support facilities.Result. The design of TPP for thermal impact on the anterior segment of the human eyeball is presented. Its fullscale studies were carried out in accordance with the existing methods of thermophysical measurements. Curves of changes in the temperature of the surface of the gelatin model of the human eyeball over time during cooling and heating were obtained for the supply currents of the thermoelectric module (TEM) included in the TPP, equal to 2.5 A, 3 A, 3.5 A, A and 1 A, 1 .2 A, 1.4 A, as well as changes in the temperature of the object of influence over time when changing the cooling mode to heating and vice versa. To assess the possibilities of heat removal from the hot junctions of TEMs in the system, data were obtained on the change in their temperature over time during the cooling effect for various values of the module supply current.Conclusion. It has been established that standard modules produced by domestic firms can be used as TEMs in the system. The duration of entering the TPP mode is about 230 s. The refore, it seems appropriate to bring the TPP to the operating mode before the actual procedures are carried out. It has been established that the duration of TPP switching from cooling to heating mode and vice versa is 230 s, which requires further optimization of the design and operating modes of the device through the use of more advanced types of TEMs and the use of forced operation of thermal modules in the transient mode.","PeriodicalId":202454,"journal":{"name":"Herald of Dagestan State Technical University. Technical Sciences","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124404528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modeling the process of refrigeration effects on food products 模拟冷藏过程对食品的影响

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-05-08 DOI: 10.21822/2073-6185-2023-50-1-24-32

R. A. Zhlobo, M. V. Shamarov, V. I. Alyoshin

引用次数: 0

Applying conditional optimization to determine the allowable loads on flexurally rigid threads 应用条件优化确定柔性刚性螺纹的允许载荷

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-02-10 DOI: 10.21822/2073-6185-2022-49-4-169-176

D. Tarasov

{"title":"Applying conditional optimization to determine the allowable loads on flexurally rigid threads","authors":"D. Tarasov","doi":"10.21822/2073-6185-2022-49-4-169-176","DOIUrl":"https://doi.org/10.21822/2073-6185-2022-49-4-169-176","url":null,"abstract":"Objective. Development of a methodology for determining the allowable loads on existing structural elements, the design model of which is a flexural-rigid thread, based on the requirements of strength and rigidity due to the changed operating conditions of structures.Method. This study is based on mathematical modeling of the problem of conditional optimization. The objective function is the total potential energy of deformation of a thread with some flexural rigidity. In this case, restrictions are imposed on strength, rigidity, and the condition of continuity of deformations. At the same time, to achieve this goal, the provisions of the strength of materials, as well as the apparatus of integral and differential calculation of functions of one or more variables, were used.Result. An assessment of the adequacy of the results obtained using the developed methodology was carried out. A numerical experiment was performed to determine the value of the allowable uniformly distributed load and the corresponding distribution of stresses and strains along the length of a thread of finite stiffness with given physical and geometric parameters. It has been established that the discrepancies in the values of the results obtained using the proposed modeling technology and the commercial computer-aided design and calculation system LIRA 10.8, implemented on the generally recognized finite element method, are no more than 5%.Conclusion. The developed technique allows setting and solving problems of determining the ultimate loads on flexural-rigid threads, based on the allowable stresses and strains, in contrast to existing commercial computer simulation systems that solve exclusively direct problems of determining the stress-strain state of various types of structures. It can be used at the stage of inspection of large-span coatings in the reconstruction of public buildings and engineering structures. ","PeriodicalId":202454,"journal":{"name":"Herald of Dagestan State Technical University. Technical Sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130947931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Determination of the bearing capacity of encentrally compressed concrete filled steel tubular columns on the basis of the deformation theory of concrete plasticity 基于混凝土塑性变形理论的钢管混凝土中压柱承载力的确定

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-02-10 DOI: 10.21822/2073-6185-2022-49-4-182-193

K. Khashkhozhev, L. I. Lesnyak, R. M. Kurachev, A. Chepurnenko

{"title":"Determination of the bearing capacity of encentrally compressed concrete filled steel tubular columns on the basis of the deformation theory of concrete plasticity","authors":"K. Khashkhozhev, L. I. Lesnyak, R. M. Kurachev, A. Chepurnenko","doi":"10.21822/2073-6185-2022-49-4-182-193","DOIUrl":"https://doi.org/10.21822/2073-6185-2022-49-4-182-193","url":null,"abstract":"Objective. The article proposes a method for finite element analysis of pipe-concrete columns in a physically nonlinear setting by reducing a three-dimensional problem to a twodimensional one based on the hypothesis of plane sections.Method.The equations of the theory of plasticity of concrete by G.A. Geniev are used. The technique was tested by comparing the solution with a calculation in a three-dimensional setting in the LIRA-SAPR software package, as well as with the experimental data of A.I. Sagadatov and calculation according to the current Russian design codes for steel-pipe concrete structures.Result. It has been established that the effective area of operation of columns with a circular cross section is small eccentricities of the longitudinal force.Conclusion. The proposed approach can be applied to the analysis of the stress-strain state and the bearing capacity of pipe-concrete columns of arbitrary section. There are no restrictions on the composition of concrete, and the shell material can be not only steel, but also fiberglass. ","PeriodicalId":202454,"journal":{"name":"Herald of Dagestan State Technical University. Technical Sciences","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126562476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Features of the work of flat large-span structures 平面大跨度结构的施工特点

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-02-10 DOI: 10.21822/2073-6185-2022-49-4-194-203

A. K. Yusupov, H. M. Muselemov, R. I. Vishtalov

引用次数: 0

Mathematical modeling of evaporation processes in a heat pump circuit 热泵回路中蒸发过程的数学建模

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-02-10 DOI: 10.21822/2073-6185-2022-49-4-177-181

V. Fedoseev, S. Loginova

引用次数: 0

Study of the dependence of the maximum normal stresses in the sections of thin-walled rods on the curvature of the bent axis in the longitudinal bending 研究了薄壁杆在纵向弯曲中截面最大正应力与弯曲轴曲率的关系

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-02-10 DOI: 10.21822/2073-6185-2022-49-4-162-168

A. S. Lichkovakha, B. A. Shemshura, S. Kuznetsov

引用次数: 0

Deployment of a fault-tolerant videoconferencing server for a virtualization-based judicial system 为基于虚拟化的司法系统部署容错视频会议服务器

Herald of Dagestan State Technical University. Technical Sciences Pub Date : 2023-02-09 DOI: 10.21822/2073-6185-2022-49-4-45-51

O. Bokova, N. Khokhlov, A. Bokova

引用次数: 0