Pub Date : 2021-10-07DOI: 10.21122/2227-1031-2021-20-5-410-419
V. V. Ivashechkin, J. Medvedeva, A. N. Kondratovich, E. S. Satsuta
The paper provides an overview of the known designs of water wells. A new design of a two-column two-filter water intake well has been also proposed, in which the filters are arranged in two tiers. This will lead to an increase in water intake capacity and will reduce the filtration rate on the approach to the filters. This, in turn, will create conditions for reducing head losses and will make it possible to reduce drawdowns in the well, ensuring a reduction in the cost of produced water. This design combines both working and reserve wells located in one borehole, which increases its reliability, durability and uninterrupted water supply to the consumer. A method for calculating the hydraulic parameters of a two-column two-filter water intake well is presented in the paper. It is based on dependencies for calculating the main geometric dimensions for a given design flow rate and hydrogeological characteristics of an aquifer, as well as formulas for determining a decrease in a well for a given period of operation when one and two pumps operate simultaneously. The basics of designing a well of the proposed design are outlined in the paper. The paper considers an example of calculation for a new well design instead of an existing typical well that has reduced its specific flow rate.
{"title":"Basics of Calculation and Design of Two-Column Two-Filter Water Intake Wells","authors":"V. V. Ivashechkin, J. Medvedeva, A. N. Kondratovich, E. S. Satsuta","doi":"10.21122/2227-1031-2021-20-5-410-419","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-5-410-419","url":null,"abstract":"The paper provides an overview of the known designs of water wells. A new design of a two-column two-filter water intake well has been also proposed, in which the filters are arranged in two tiers. This will lead to an increase in water intake capacity and will reduce the filtration rate on the approach to the filters. This, in turn, will create conditions for reducing head losses and will make it possible to reduce drawdowns in the well, ensuring a reduction in the cost of produced water. This design combines both working and reserve wells located in one borehole, which increases its reliability, durability and uninterrupted water supply to the consumer. A method for calculating the hydraulic parameters of a two-column two-filter water intake well is presented in the paper. It is based on dependencies for calculating the main geometric dimensions for a given design flow rate and hydrogeological characteristics of an aquifer, as well as formulas for determining a decrease in a well for a given period of operation when one and two pumps operate simultaneously. The basics of designing a well of the proposed design are outlined in the paper. The paper considers an example of calculation for a new well design instead of an existing typical well that has reduced its specific flow rate.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"14 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87140656","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-338-344
A. A. Lobaty, A. Y. Bumai, S. S. Prohorovith
. The problem of analytical synthesis of the control acceleration for an unmanned aerial vehicle (UAV) during its flight along a complex trajectory, consisting of sequentially located horizontal flight sections, located at different heights relative to the earth's surface has been solved in the paper. The problem has been solved as an analytical definition of the optimal control of a linear non-stationary system for a specified minimized quality functional. The mathematical model of the system is presented in the form of differential equations of UAV motion in the vertical plane of a fixed coordinate system related to the earth's surface. A feature of the proposed methodology for solving the problem is the substantiation of the original form of the minimized functional and parameters included in the law of variation of the control acceleration obtained by known methods. As the components of the quality functional, the values of coordinates and velocity of the UAV are considered and they are specified at the corresponding points in space through which the UAV path must pass, in order to obtain the optimal curvature of the trajectory. The derived mathematical dependences make it possible to implement them on board of an aircraft and, ultimately, solve the problem of ensuring the minimum energy consumption when controlling an object (UAV). Computer simulation of the analytically obtained results in the form of the UAV flight trajectory and the processes of changing its acceleration and speed have shown the efficiency of the proposed technique and the prospects of its use at the initial stage of the synthesis of the UAV control system.
{"title":"Analytical Synthesis of Control Acceleration of Unmanned Aerial Vehicle","authors":"A. A. Lobaty, A. Y. Bumai, S. S. Prohorovith","doi":"10.21122/2227-1031-2021-20-4-338-344","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-338-344","url":null,"abstract":". The problem of analytical synthesis of the control acceleration for an unmanned aerial vehicle (UAV) during its flight along a complex trajectory, consisting of sequentially located horizontal flight sections, located at different heights relative to the earth's surface has been solved in the paper. The problem has been solved as an analytical definition of the optimal control of a linear non-stationary system for a specified minimized quality functional. The mathematical model of the system is presented in the form of differential equations of UAV motion in the vertical plane of a fixed coordinate system related to the earth's surface. A feature of the proposed methodology for solving the problem is the substantiation of the original form of the minimized functional and parameters included in the law of variation of the control acceleration obtained by known methods. As the components of the quality functional, the values of coordinates and velocity of the UAV are considered and they are specified at the corresponding points in space through which the UAV path must pass, in order to obtain the optimal curvature of the trajectory. The derived mathematical dependences make it possible to implement them on board of an aircraft and, ultimately, solve the problem of ensuring the minimum energy consumption when controlling an object (UAV). Computer simulation of the analytically obtained results in the form of the UAV flight trajectory and the processes of changing its acceleration and speed have shown the efficiency of the proposed technique and the prospects of its use at the initial stage of the synthesis of the UAV control system.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"1 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81282692","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-345-351
A. Liashok, Y. Popova
Sintered friction materials are widely used in friction units of automotive vehicles and special purpose vehicles. The main purpose is to transmit torque to the actuator. The development of the technology market requires the development and use of new units. At the same time, the creation of new materials is required, which also applies to sintered friction materials. This group of materials is characterized by a high service life, efficiency of torque transmission, as well as the ability to restore performance in case of violation of operating modes. One of the most significant parameters characterizing a sintered friction material is wear resistance. In most cases, it determines not only the resource of the unit itself, but the entire machine as a whole. A special place is occupied by brake units, which also use friction materials. The increased wear resistance of the friction material contributes to a decrease in the efficiency and service life of the brake system. Evaluation of the wear resistance of a friction material for the given operational parameters is a very long and costly process. The development of methodology and methods for accelerating the assessment of wear resistance is an important scientific and practical task. The paper presents the results of using artificial neural networks to predict the service life of a composite friction material based on copper on the sliding speed, pressure on the material and the amount of lubricant supplied to the friction zone. An artificial neural network has been trained using an array of experimental data for the FM-15 friction material. The training results have shown high accuracy, correctness of the proposed and implemented network architecture. The developed software has demonstrated its efficiency and the possibility of using it in calculations to determine the wear of a composite friction material.
{"title":"Using Artificial Neural Networks to Determine Wear of Composite Friction Material","authors":"A. Liashok, Y. Popova","doi":"10.21122/2227-1031-2021-20-4-345-351","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-345-351","url":null,"abstract":"Sintered friction materials are widely used in friction units of automotive vehicles and special purpose vehicles. The main purpose is to transmit torque to the actuator. The development of the technology market requires the development and use of new units. At the same time, the creation of new materials is required, which also applies to sintered friction materials. This group of materials is characterized by a high service life, efficiency of torque transmission, as well as the ability to restore performance in case of violation of operating modes. One of the most significant parameters characterizing a sintered friction material is wear resistance. In most cases, it determines not only the resource of the unit itself, but the entire machine as a whole. A special place is occupied by brake units, which also use friction materials. The increased wear resistance of the friction material contributes to a decrease in the efficiency and service life of the brake system. Evaluation of the wear resistance of a friction material for the given operational parameters is a very long and costly process. The development of methodology and methods for accelerating the assessment of wear resistance is an important scientific and practical task. The paper presents the results of using artificial neural networks to predict the service life of a composite friction material based on copper on the sliding speed, pressure on the material and the amount of lubricant supplied to the friction zone. An artificial neural network has been trained using an array of experimental data for the FM-15 friction material. The training results have shown high accuracy, correctness of the proposed and implemented network architecture. The developed software has demonstrated its efficiency and the possibility of using it in calculations to determine the wear of a composite friction material.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"62 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80795461","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-310-319
A. Yurkevich, A. Tereshin, V. Soldatkin
The paper proposes a new type of a mechanical continuously variable transmission with internal force functions to upgrade the energy efficiency of a vehicle equipped with a conventional engine. The prototype of the transmission is a well-known V. F. Maltsev concurrent pulse variator in which freewheel mechanism driven members are supplemented with elastic torsions shafts. It is shown that the variator turns into a continuous transformer – a mechanical continuously variable transmission with internal force functions. There is an internal automaticity and continuity in the entire range of gear ratio changes. The configuration engineering solution is implemented in the engineering prototype. The aim of the research is experimental study of the properties and characteristics of such a mechanical continuously variable transmission. The kinematic configuration and the main structural dimensions of the engineering prototype are given. Special testing facility and measuring-and-recording equipment have been developed. A set of parameters to be recorded has been specified. The accuracy of their measurement is statistically estimated. The results of the experiments are presented in terms of output and input torque dependencies on the speed of the driven shaft. It is shown that the transmission characteristics in their dimensionless form (transformer ratio and efficiency) in the function of internal gear ratio are universal. The possibility of obtaining an infinite kinematic and significant power transmission ranges by independently changing the internal link oscillation range (level of the force function) and the rotation frequency of the drive shaft has been experimentally shown. The transmission has high transforming and energy properties, which are higher than those of hydrodynamic gears.
{"title":"Experimental Characteristics of Mechanical Continuously Variable Transmission with Internal Force Functions","authors":"A. Yurkevich, A. Tereshin, V. Soldatkin","doi":"10.21122/2227-1031-2021-20-4-310-319","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-310-319","url":null,"abstract":"The paper proposes a new type of a mechanical continuously variable transmission with internal force functions to upgrade the energy efficiency of a vehicle equipped with a conventional engine. The prototype of the transmission is a well-known V. F. Maltsev concurrent pulse variator in which freewheel mechanism driven members are supplemented with elastic torsions shafts. It is shown that the variator turns into a continuous transformer – a mechanical continuously variable transmission with internal force functions. There is an internal automaticity and continuity in the entire range of gear ratio changes. The configuration engineering solution is implemented in the engineering prototype. The aim of the research is experimental study of the properties and characteristics of such a mechanical continuously variable transmission. The kinematic configuration and the main structural dimensions of the engineering prototype are given. Special testing facility and measuring-and-recording equipment have been developed. A set of parameters to be recorded has been specified. The accuracy of their measurement is statistically estimated. The results of the experiments are presented in terms of output and input torque dependencies on the speed of the driven shaft. It is shown that the transmission characteristics in their dimensionless form (transformer ratio and efficiency) in the function of internal gear ratio are universal. The possibility of obtaining an infinite kinematic and significant power transmission ranges by independently changing the internal link oscillation range (level of the force function) and the rotation frequency of the drive shaft has been experimentally shown. The transmission has high transforming and energy properties, which are higher than those of hydrodynamic gears.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"23 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81871966","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-357-364
Yu. Mialeshka.
A meaningful characteristic of modern industrial production is given and prospects for the modernization of the Belarusian industry through new industrialization are identified in the paper. In this regard, the objectives of the study have been determined: to consider modern concepts of the transformation of economic systems under the influence of technological progress, to substantively characterize the new industrialization, including to describe the technological and organizational features of the new intentional production, to identify its distinctive features, to determine the prospects for using the concept of new industrialization for modernization of the Belarusian industry. The methodological basis was the general scientific methods and principles of сognition, namely: the method of deduction and induction, the method of comparative analysis, historical approach. The author considers the new industrialization as an economic structure that has developed as a result of the spread of digital technologies in a modern socially-oriented, predominantly market economy. The technological basis of the new industrial production is cyber-physical production systems that operate through the industrial Internet of things, the Internet of services and network mechanisms of interaction between all participants in the value added chain. The development of digital production and digital services entails the digitalization of business models. The result is flexible, adaptive, individualized industrial production through the triad of digital production, digital services and digital business models. When modernizing the Belarusian industrial complex, aimed at developing high-tech and knowledge-intensive industrial production and increasing the efficiency of traditional industries through the use of a wide variety of new technologies, the priority should be the comprehensive digitalization of production, services and business models.
{"title":"New Industrialization and Trends in Modernization of Belarusian Industry","authors":"Yu. Mialeshka.","doi":"10.21122/2227-1031-2021-20-4-357-364","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-357-364","url":null,"abstract":"A meaningful characteristic of modern industrial production is given and prospects for the modernization of the Belarusian industry through new industrialization are identified in the paper. In this regard, the objectives of the study have been determined: to consider modern concepts of the transformation of economic systems under the influence of technological progress, to substantively characterize the new industrialization, including to describe the technological and organizational features of the new intentional production, to identify its distinctive features, to determine the prospects for using the concept of new industrialization for modernization of the Belarusian industry. The methodological basis was the general scientific methods and principles of сognition, namely: the method of deduction and induction, the method of comparative analysis, historical approach. The author considers the new industrialization as an economic structure that has developed as a result of the spread of digital technologies in a modern socially-oriented, predominantly market economy. The technological basis of the new industrial production is cyber-physical production systems that operate through the industrial Internet of things, the Internet of services and network mechanisms of interaction between all participants in the value added chain. The development of digital production and digital services entails the digitalization of business models. The result is flexible, adaptive, individualized industrial production through the triad of digital production, digital services and digital business models. When modernizing the Belarusian industrial complex, aimed at developing high-tech and knowledge-intensive industrial production and increasing the efficiency of traditional industries through the use of a wide variety of new technologies, the priority should be the comprehensive digitalization of production, services and business models.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"41 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89816271","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-287-295
K. Y. Bykov, I. V. Kachanov, I. M. Shatalov
The paper presents a mathematical model developed for calculating the force effect on the punch in the process of high-speed combined hot extrusion of bimetallic road milling picks under plane deformation conditions. To solve the problem, the process is divided into two phases: acceleration phase and braking phase, which consists of two stages. A distinctive feature of the acceleration phase is that it allows the analysis of reverse extrusion, in the process of which the metal flows in the opposite direction to the punch stroke. A method for calculating the force acting on the punch at each phase of the process of plastic flow of a bimetallic workpiece into a matrix cavity with three deformation zones is presented in the paper. While solving the problem in a quasi-static formulation and proceeding from the conditions of the minimum power of internal forces, equations have been obtained for calculating the optimal field parameters aopt, bopt, gopt, depending on the elongation coefficients l and the friction coefficient m. The equations obtained within the framework of the developed model are quite correct, since they allow determining the minimum force acting on the punch. The considered calculation model and equations can be used in the development of industrial technology for high-speed combined hot extrusion of flat-step bimetallic road milling picks.
{"title":"Power Mode of High-Speed Combined Extrusion of Flat Bimetallic Road Milling Picks","authors":"K. Y. Bykov, I. V. Kachanov, I. M. Shatalov","doi":"10.21122/2227-1031-2021-20-4-287-295","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-287-295","url":null,"abstract":"The paper presents a mathematical model developed for calculating the force effect on the punch in the process of high-speed combined hot extrusion of bimetallic road milling picks under plane deformation conditions. To solve the problem, the process is divided into two phases: acceleration phase and braking phase, which consists of two stages. A distinctive feature of the acceleration phase is that it allows the analysis of reverse extrusion, in the process of which the metal flows in the opposite direction to the punch stroke. A method for calculating the force acting on the punch at each phase of the process of plastic flow of a bimetallic workpiece into a matrix cavity with three deformation zones is presented in the paper. While solving the problem in a quasi-static formulation and proceeding from the conditions of the minimum power of internal forces, equations have been obtained for calculating the optimal field parameters aopt, bopt, gopt, depending on the elongation coefficients l and the friction coefficient m. The equations obtained within the framework of the developed model are quite correct, since they allow determining the minimum force acting on the punch. The considered calculation model and equations can be used in the development of industrial technology for high-speed combined hot extrusion of flat-step bimetallic road milling picks.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"12 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85070010","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-296-301
N. M. Selivonchik, N. L. Nesterenko
According to the requirements of the “Rules for industrial safety of cranes”, anti-theft devices must ensure that cranes under the influence of wind force stop at any point on the track, including at the junction of rails connected by side strips. Various types of anti-theft crane devices recommended for use have a number of disadvantages. Thus, the supply of anti-theft crane devices made in the form of lever grips interacting with the rail head with mechanisms for disengaging and converging grippers with electromechanical, electromagnetic, hydraulic or pneumatic drives complicates their design. There are also known anti-theft crane devices, in which the stopping of cranes on a rail track is carried out by a locking eccentric interacting with the surface of the rail head. The reliability of such devices is insufficient, since, due to the constant force of the spring, the adhesion force of the eccentric to the rail does not depend on the changing wind force. The paper proposes the basics of calculating the anti-theft crane device, representing the kinematic connection of two mechanisms – eccentric and thick-borne, which allows to solve a number of the above problems.
{"title":"Basics of Calculating Anti-Theft Crane Device from Eccentric and Tick-Borne Mechanisms","authors":"N. M. Selivonchik, N. L. Nesterenko","doi":"10.21122/2227-1031-2021-20-4-296-301","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-296-301","url":null,"abstract":"According to the requirements of the “Rules for industrial safety of cranes”, anti-theft devices must ensure that cranes under the influence of wind force stop at any point on the track, including at the junction of rails connected by side strips. Various types of anti-theft crane devices recommended for use have a number of disadvantages. Thus, the supply of anti-theft crane devices made in the form of lever grips interacting with the rail head with mechanisms for disengaging and converging grippers with electromechanical, electromagnetic, hydraulic or pneumatic drives complicates their design. There are also known anti-theft crane devices, in which the stopping of cranes on a rail track is carried out by a locking eccentric interacting with the surface of the rail head. The reliability of such devices is insufficient, since, due to the constant force of the spring, the adhesion force of the eccentric to the rail does not depend on the changing wind force. The paper proposes the basics of calculating the anti-theft crane device, representing the kinematic connection of two mechanisms – eccentric and thick-borne, which allows to solve a number of the above problems.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"106 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75754145","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-320-328
V. Molodin, A. Anufrieva, S. Leonovich
During operation, concrete and reinforced concrete structures are exposed to the aggressive environment of carbon dioxide. During the reconstruction and overhaul of the berthing facilities in the coastal zone of the seas of the Far East, a weak bond strength of the “old” carbonated and “new” repair concrete has been established in the paper. The reason that prevents reliable adhesion of concrete is the formation of fragile corrosion products in the pores and on the surface of “old” concrete. Accelerated tests of concrete carbonization from exposure to carbon dioxide have been carried out in the course of the study. The structure of the carbonized cement stone has been examined using a scanning electron microscope. The research results have made it possible to assess the structure of a “healthy” cement stone and affected by carbonization. The performed analysis of concrete carbonization process, including micrographs of the samples, has shown that under the action of carbon dioxide, the surface layer with a thickness of 4 mm and more undergoes structural restructuring. Fibrous formations are destroyed, and the carbonized volume is a heap of loosely bound loose new formations and films blocking the entrances to the capillary system of concrete. They are not a reliable basis for adhesion of “new” and “old” concrete and prevent the penetration of liquid containing cement dissolution products from “new” concrete into the capillaries of the healthy structure of the “old” concrete for their reliable connection.
{"title":"Influence of Carbonization of Concrete Surfaces on their Adhesion with Freshly-Laid Concrete","authors":"V. Molodin, A. Anufrieva, S. Leonovich","doi":"10.21122/2227-1031-2021-20-4-320-328","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-320-328","url":null,"abstract":"During operation, concrete and reinforced concrete structures are exposed to the aggressive environment of carbon dioxide. During the reconstruction and overhaul of the berthing facilities in the coastal zone of the seas of the Far East, a weak bond strength of the “old” carbonated and “new” repair concrete has been established in the paper. The reason that prevents reliable adhesion of concrete is the formation of fragile corrosion products in the pores and on the surface of “old” concrete. Accelerated tests of concrete carbonization from exposure to carbon dioxide have been carried out in the course of the study. The structure of the carbonized cement stone has been examined using a scanning electron microscope. The research results have made it possible to assess the structure of a “healthy” cement stone and affected by carbonization. The performed analysis of concrete carbonization process, including micrographs of the samples, has shown that under the action of carbon dioxide, the surface layer with a thickness of 4 mm and more undergoes structural restructuring. Fibrous formations are destroyed, and the carbonized volume is a heap of loosely bound loose new formations and films blocking the entrances to the capillary system of concrete. They are not a reliable basis for adhesion of “new” and “old” concrete and prevent the penetration of liquid containing cement dissolution products from “new” concrete into the capillaries of the healthy structure of the “old” concrete for their reliable connection.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"1 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84989461","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-352-356
R. Ivut, P. Popov, P. I. Lapkovskaya, N. Sheveleva
The paper considers an algorithm for solving the problem of finding the optimal location of key objects of transport and warehouse infrastructures within the framework of a methodological approach to designing logistics infrastructure in the territory of the region of the countries. The methodological approach includes three stages. At the first stage, areas are determined where it is advisable to locate key objects of the regional logistics infrastructure. Further, using the models developed by the authors, the linking of warehouse infrastructure objects on the ground has been carried out and, taking into account the designed warehouse network, the optimal dislocation of transport infrastructure objects has been determined. To find the optimal locations for the objects for regional logistics infrastructure facilities, the authors propose an algorithm that is applicable both for building warehouse and transport infrastructures due to the similarity of the models. The algorithm is based on the method of constructing a sequence of plans. At the initial stage, the final expansion is constructed for the set of plans under consideration. For a given set, a minorant has been determined for the cost function associated with the placement and maintenance of infrastructure facilities, the movement of goods, and the haul of an empty vehicle. After that, an iterative algorithm has been formed that determines the sequence of optima of the minorant on a sequence of nested sets. At the first step, an element of the set of plans has been found that minimizes the minorant, at the next step, the found element is excluded from the set under consideration, and a new optimum is sought on the remaining set for which the minorant takes the minimum value. To eliminate multiple plans, it is advisable to use dynamic programming procedures. The limits of applicability of the method for constructing a sequence of plans are determined by the ability to construct an extension of the set of plans for placing objects, select a minorant on it, and build an algorithm for ordering optima.
{"title":"Algorithm for Solving Problem of Designing Regional Logistics Infrastructure","authors":"R. Ivut, P. Popov, P. I. Lapkovskaya, N. Sheveleva","doi":"10.21122/2227-1031-2021-20-4-352-356","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-352-356","url":null,"abstract":"The paper considers an algorithm for solving the problem of finding the optimal location of key objects of transport and warehouse infrastructures within the framework of a methodological approach to designing logistics infrastructure in the territory of the region of the countries. The methodological approach includes three stages. At the first stage, areas are determined where it is advisable to locate key objects of the regional logistics infrastructure. Further, using the models developed by the authors, the linking of warehouse infrastructure objects on the ground has been carried out and, taking into account the designed warehouse network, the optimal dislocation of transport infrastructure objects has been determined. To find the optimal locations for the objects for regional logistics infrastructure facilities, the authors propose an algorithm that is applicable both for building warehouse and transport infrastructures due to the similarity of the models. The algorithm is based on the method of constructing a sequence of plans. At the initial stage, the final expansion is constructed for the set of plans under consideration. For a given set, a minorant has been determined for the cost function associated with the placement and maintenance of infrastructure facilities, the movement of goods, and the haul of an empty vehicle. After that, an iterative algorithm has been formed that determines the sequence of optima of the minorant on a sequence of nested sets. At the first step, an element of the set of plans has been found that minimizes the minorant, at the next step, the found element is excluded from the set under consideration, and a new optimum is sought on the remaining set for which the minorant takes the minimum value. To eliminate multiple plans, it is advisable to use dynamic programming procedures. The limits of applicability of the method for constructing a sequence of plans are determined by the ability to construct an extension of the set of plans for placing objects, select a minorant on it, and build an algorithm for ordering optima.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"17 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89480096","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}
Pub Date : 2021-07-19DOI: 10.21122/2227-1031-2021-20-4-329-337
E. I. Batyanovskiy, A. I. Bondarovich, N. N. Kalinovskaya, P. V. Ryabchikov
. The paper presents the results of the development and implementation of the technology of self-compacting heavy structural concrete and the technology of concreting with its use of the largest foundation slab in Belarus (concrete volume ~9100 m3) of a high-rise building at the facility “Construction of a multifunctional complex in Minsk within the boundaries of Filimonova Street – Avenue Nezavisimosty – Makayonka Street”. The results of research are shown, which ensured the production of self-compacting concrete of class C35/45 with water resistance up to W20 (with the required W12 according to the project) from concrete mixtures of the maximum cone expansion of the PK6 (RK6) grade for three zones of the foundation slab different in degree of reinforcement: lower, middle and upper, with a total structure height of 3.5 m and plan dimensions ~(83´34) m. The technology of continuous (seamless) concreting has been developed and implemented, which made it possible to lay ~9100 m3 of concrete into the structure without defects within 42 hours of continuous operation, and a system of technological measures that prevented temperature cracking in concrete. The homogeneity of the physical and mechanical properties of concrete, confirmed by control tests, is ensured due to the uniform supply of the concrete mixture (from six concrete pumps at the same time) in layers 200–300 mm high with a distance between the supply points of about 5–6 m and the vertical arrangement of the “trunks” of the concrete pipes during delivery of concrete to each point, as well as the fact that the time for feeding the next volume of concrete was significantly less than the setting time of the previously laid concrete (with a total concreting speed £0.1 m/h). Standardized and original test methods for concrete mixtures, hardening kinetics and properties of hardened concrete have been used during the development, research and implementation of the project. Control tests of physical and mechanical properties and characteristics of concrete, carried out at BNTU together with authorized organizations controlling the progress of construction, as well as in independent (third-party) organizations, have confirmed their compliance with the design requirements.
{"title":"Self-Compacting Concrete and Concreting Technology for Foundation Block Using 9000 Cubic Meters of Concrete","authors":"E. I. Batyanovskiy, A. I. Bondarovich, N. N. Kalinovskaya, P. V. Ryabchikov","doi":"10.21122/2227-1031-2021-20-4-329-337","DOIUrl":"https://doi.org/10.21122/2227-1031-2021-20-4-329-337","url":null,"abstract":". The paper presents the results of the development and implementation of the technology of self-compacting heavy structural concrete and the technology of concreting with its use of the largest foundation slab in Belarus (concrete volume ~9100 m3) of a high-rise building at the facility “Construction of a multifunctional complex in Minsk within the boundaries of Filimonova Street – Avenue Nezavisimosty – Makayonka Street”. The results of research are shown, which ensured the production of self-compacting concrete of class C35/45 with water resistance up to W20 (with the required W12 according to the project) from concrete mixtures of the maximum cone expansion of the PK6 (RK6) grade for three zones of the foundation slab different in degree of reinforcement: lower, middle and upper, with a total structure height of 3.5 m and plan dimensions ~(83´34) m. The technology of continuous (seamless) concreting has been developed and implemented, which made it possible to lay ~9100 m3 of concrete into the structure without defects within 42 hours of continuous operation, and a system of technological measures that prevented temperature cracking in concrete. The homogeneity of the physical and mechanical properties of concrete, confirmed by control tests, is ensured due to the uniform supply of the concrete mixture (from six concrete pumps at the same time) in layers 200–300 mm high with a distance between the supply points of about 5–6 m and the vertical arrangement of the “trunks” of the concrete pipes during delivery of concrete to each point, as well as the fact that the time for feeding the next volume of concrete was significantly less than the setting time of the previously laid concrete (with a total concreting speed £0.1 m/h). Standardized and original test methods for concrete mixtures, hardening kinetics and properties of hardened concrete have been used during the development, research and implementation of the project. Control tests of physical and mechanical properties and characteristics of concrete, carried out at BNTU together with authorized organizations controlling the progress of construction, as well as in independent (third-party) organizations, have confirmed their compliance with the design requirements.","PeriodicalId":42375,"journal":{"name":"Science & Technique","volume":"25 1","pages":""},"PeriodicalIF":0.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86825884","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：