The negative trends in the country's economy associated with the COVID-19 pandemic have also affected the construction industry of the Russian Federation. The impossibility of transferring construction to a remote mode, the suspension of the work of construction companies affected their financial activities. In addition to government support, construction companies must independently seek ways to improve their performance. One of the ways to improve the quality of management in the implementation of investment and construction projects is to use the approach of integrated project implementation. Within the framework of this approach, it is necessary to focus on quality management at all stages of the life cycle. It is proposed to use this approach in conjunction with the methods of business information modeling technology for projects.
Keywords: Integrated Project Delivery, lean construction, business information modeling
The possibility of using European standards, manuals and manuals for the calculation of elements of nodes of frame structures according to criteria that have not been reflected in Russian standards today is being considered. Numerical methods have been used to analyze the bearing capacity of frame nodes for various combinations of longitudinal forces and bending moments. The formation of residual plastic deformations in the elements of the nodes of the frame structures is considered. The nodes were calculated using the ANSYS software package, and a comparative analysis of the calculation results according to European and Russian standards was performed based on the results of the calculation. The question is raised about the need for further numerical studies of the work of steel frame assemblies, including the conduct of field tests, as well as the development of new methods for calculating frame assemblies with regard to plastic deformations. As a result of the calculations and calculations, the need to take into account the fatigue survivability of steel frame assemblies is established, which is associated with the probability of the occurrence of full design loads for the design life.
Keywords: European standards, calculation of steel elements, nodes of frame structures, bearing capacity, plastic deformations, fatigue survivability, low-cycle design loads, full design load, redistribution of internal forces, flexibility of rigid nodes
The article presents the results of studying the effect of the loading of active metal on the physicochemical properties of cobalt catalysts for the Fischer-Tropsch synthesis on a silicate support, promoted with aluminum. Using the BET, XRF, TPR, TPD-H2 methods, it has been established that the optimum cobalt content is 15‒18 wt. %.
Keywords: Fischer-Tropsch synthesis, catalyst, cobalt, active component, loading
The article uses a method of modernizing solutions for constructing vehicle monitoring models made using standard Bragg structures. The applicability of fiber Bragg gratings (FBGs) with structural defects such as phase shifts is carried out. This article proposes a fiber-optic sensor system (FOSS) based on FBG with a phase π-shift, which makes it possible to switch from optoelectronic interrogation methods to radio-photonic ones. The radio-photon approach is presented as an effective method for detecting vehicles in normal traffic. The principle of information signal formation when measuring vehicle parameters. This FOSS allows, on the one hand, to get rid of an expensive optoelectronic interrogator, on the other hand, it requires the construction of neural network models for its work to determine cars of different types and weights.
Keywords: fiber bragg gratings, phase shift, distributed sensor networks, portable sensor, traffic density monitoring
Concentration changes of refraction and frequency of raman spectrum in melts of salt systems of alkali metals containing nitrate and thiocyanate anions are shown. The change in molar refraction and frequency confirmed the concept of additivity and linearity of isotherms when changing composition.
Keywords: molten salt, nitrates and thiocyanates of alkali metals, refraction, raman-spectr
The article presents scientific and technological aspects of improving grain cargo transportation in the southern region with the participation of railway transport. Based on the analysis of volume indicators of transportation, existing delivery technologies, scientific provisions in the studied area, the directions of development of grain cargo transportation logistics are identified. The prospects of increasing the supply of grain cargo to the ports of the Azov-black sea basin are considered. The review of logistics technologies of grain cargo delivery to the ports of the Azov-black sea basin by rail is performed. New information tools have been developed to support decision - making when optimizing cargo flows and developing grain delivery plans under multi-Agency conditions. A system of temporary criteria for evaluating cargo flow distribution plans at the port road polygon has been formed .The article presents statistics on purchasing innovative rolling stock for the specified volumes of grain cargo transportation.
Keywords: railway transport, export, logistics, management, technology, transportation organization, outsourcing, utilitarianism, egalitarianism, distribution of cargo flows, optimization, information technology, mathematical modeling
An auxiliary subsystem of a multi-agent robotic sowing system for agricultural crops, including autonomous robots functioning as part of a group, is considered as an object of research. The aim of the study is to improve the management of adaptability and productivity of agricultural plants. The tasks of the study included the development of the simplest autonomous robot for introducing working fluids into the cenosis and the choice of its parameters. The experimental data were processed by the methods of mathematical statistics. The developed autonomous robot is made of polymer gel and has the properties of a quasi-liquid body. Its parameters are determined, presented experimentally certain mathematical dependences of the interaction of autonomous robots with working fluids, for example, rainwater.
Keywords: seeding, watering, robotic subsystem, autonomous robot, polymer hydrogel, quasi-liquid body
The article provides a brief analysis of the starting processes of electrical devices. The mathematical formulation of the problem of synthesis of starting rheostats is formulated and its solution is proposed. The main condition for optimal starting of electric motors using thermistor rheostats is presented. Optimal diagrams of the starting current and set of revolutions are given. and also, the change in heat losses in the anchor chain. Recommendations on the layout of starting rheostats are given.
Keywords: thermistor rheostat, optimal start-up, thermal start-up characteristic, optimal control problem, DC motor, boundary conditions, speed
This article illustrates specifically how to use least squares method (LSM) and sensitivity function to cope with parametric identification problems. The object of this task is BLDC motor. The example of BLDC can justify the application of LSM and sensitivity function method for estimating nonlinear dynamic objects’ parameters, and the application for motor controlling system in particular. The model in the article is conducted by Matlab. The output is a proof to convey that the method used in solving the problem is accurate, and proves the possibility of its application in scientific and engineering field.
Keywords: parametric identification, least squares method, sensitivity function, BLDC motor, electric drive
The article proposes a thermodynamic approach that allows us to more accurately represent the flow modes of quasi-stationary gas through a long step gas pipeline . It takes into account the peculiarities of the operation of side gas venting devices of small-caliber automatic guns on the principle of automatic operation. We use a combination of the main characteristics that represent the operation of such systems under difficult loading conditions and high temperatures. These are mainly gas consumption, heat transfer losses, gas flow rate, improvement of the approach to the solution of ensuring the appropriate parameters to ensure the reliable operation of the relevant technical systems with the possibility of recommendations after appropriate tests of such products.
Keywords: step gas pipeline, side gas outlet device, gas flow, thermodynamic parameters, heat loss, filling period, gas consumption, automatic weapons systems
Rail transport plays a key role in the transport of passengers and goods. The high demand for effective means of flaw detection of high-speed rails, which is an important component of railway safety, is justified by the constantly growing number of vehicles and their speed . Failure of elements of the railway infrastructure entails huge losses. In this regard, the analysis and forecasting of the state of elements of the railway infrastructure is an urgent task. This article analyzes modern methods for diagnosing the state of a rail track from a mobile bogie or a conventional locomotive. A method for diagnostics of a rail track is proposed, based on registration of vibrations near the rolling surface of rails and processing these signals using neural networks.
Keywords: rail flaw detection, wheel surface, algorithm, IMM, MEMS, control system, inertial sensor, rail defect, contactless measurement
The article describes a device for simulating a control object for automated temperature control systems, a mathematical model of the heating and cooling processes of an isolated room, modeling temperature effects on the control object, and a method for implementing a control object simulation on a microcontroller. The device will allow debugging and testing of automated temperature control systems under laboratory conditions, which will improve the quality of temperature control systems being developed.
Keywords: temperature control, automation of temperature control process, mathematical modeling
The goal of the paper is to consider the major ways of word formation in the modern English language and to analyse some of the word-building models, which have emerged relatively recently. As the material for the paper we have collected modern cognitive-semantic studies, Russian and foreign research works devoted to brand new words in English, lexical data from native speakers and the authors’ observation as well as the notes made during the visits of Great Britain in 2010-2020.
Keywords: word-building, word-building models, word formation, modern English, lexical item, lexical unit, tendency, neologism, etymology, modern English-speaking community
The work consists of two parts and is devoted to a comparative analysis of the declared cognitive and actually perceived affective relations to friendship. In the second part, the distribution functions for the entire hierarchical system of factors identified in the first part and reflecting the structure of the cognitive perception of friendship by DSTU students are presented. It was found that the overall cognitive attitude of the group is positive. For two indicators of the second level and the integral factor of all cognitive perception, about 80% of all respondents are characterized by positive values of these indicators. For the third factor of the second level, the subgroup with a positive perception (60%) is also larger than with a negative one (40%), but not so much. The affective component of students ' attitudes towards friendship gives a completely different picture. Here, 57% of respondents are characterized by an almost neutral emotional attitude to it, while only 29% are positive. All this suggests that in the group as a whole, students position a more positive relationship to friendship on a cognitive level than they actually feel emotionally. We associate this with the influence of society (both the immediate environment in direct communication, and through literature, art, mass media, etc.). The paper also analyzes the relationship between cognitive and affective attitudes to friendship at the individual level. In General, there is no such connection for the studied audience, even statistically (the correlation coefficient is only 0.17). But if we divide the entire audience into two subgroups, characterized by both the excess of cognitive perception over affective, and with the opposite ratio, then for them separately there is already a positive statistical relationship.
Keywords: friendship, pilot survey, cognitive component, hierarchical factorization method, distribution functions, affective component, comparative analysis
The search for technological solutions for the organization of lean production at precast concrete enterprises was carried out. Options for rational use of rock crushing screenings as a filler and filler for self-compacting fine-grained concrete are considered. The optimal dosage of limestone crushing screenings in the composition of fine aggregate for the preparation of self-compacting mixtures has been determined. It was found that the enrichment of very fine Sands with large fractions of Sandstone crushing screening in an optimal amount reduces the intergranular voidness and reduces the water demand of the fine-grained mixture.
Keywords: lean production, rock crushing screenings, optimization of grain composition of aggregate, self-compacting fine-grained concretes, superplasticizer based on polyaryl and polycarboxylate esters
A scheme and procedure for carrying out emanation tests of radon-protective coatings on standard concrete samples are proposed. The results of testing the material "Silor-Ultra" as an effective radon protective coating are shown.
Keywords: radioactivity, radon, radiometer, concrete, standard sample, antiradon protection, radon protection coating, radon insulation, emanation tests
The analysis is made of the use of expanded clay gravel in cement-sand mortar in order to reduce ice at the boundary between the pile and the mortar. The application of expanded clay concrete in block-modular buildings is considered. Lightweight design and reduced heatloss are proven.
Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production
The article presents an assessment of the environmental costs of dust pollution in local construction. The environmental assessment of construction in the region should take into account the optimal conditions for preventing damage to all related areas of activity, both during construction and throughout the life cycle of the project. Under the damage caused to the environment by dust emissions from construction and other sources, we mean additional costs necessary to eliminate the consequences of atmospheric pollution. Losses in the cost and productivity of finished construction products are increasing very significantly due to the introduction of measures to protect the environment from dust emissions. These losses are especially noticeable in the production of earthwork, installation, and plastering works. The purpose of the study is to determine the cost of damage caused by dust pollution, develop and propose solutions to reduce this type of damage and associated environmental costs.
Keywords: environmental safety, environmental monitoring, air protection, ecology in construction, dust suppression, dust deposition, dust collection systems, labor protection in construction
The article considers the main approaches to the organization of ecological management and environmental safety at industrial enterprises in Russia, highlights the key problems and trends of environmental management in industry, factors and conditions for ensuring environmental safety in the production sector. Based on a comprehensive analysis of scientific literature and activities to ensure the implementation of ecological management of large industrial enterprises in the country, the main directions and problems of practical implementation of environmental management, as well as the design and operation of environmental safety systems in the industrial sector are identified: insufficient experience in developing and implementing an environmental strategy; fragmented use of elements and methods of environmental management; lack of methodological support for effective integration of the environmental management system into the management system of industrial enterprises; problems of corporate governance and others.
Keywords: ecological management, ecological safety, ecological management, environmental safety management system, industrial enterprise management
Fiber-reinforced concrete is a promising type of concrete, which in the near future may take a fairly large share in the total volume of concrete produced. Dispersed reinforcement fibers are a versatile material that can be introduced into various types of concrete. This additive may later be as common as plasticizers for modern concrete mixes. Fibro fibers can be used for the production of concrete products in stationary reinforced concrete plants or on-site installations for the production of ready-mixed concrete. The paper examines the influence of parameters on the index of bending strength of the material, as the main one, which is aimed at the introduction of fiber. The results of the influence of the characteristics of dispersed reinforcement on the effectiveness of the introduction of these additives and the final construction and strength properties of heavy concrete are described.
Keywords: dispersed reinforcement, basalt fiber, polypropylene fiber, fiber concrete, prismatic strength, Flexural strength
This study presents the results of the development of a polymer composite material with good dielectric properties, which allows it to be used in the radio and electrical industries. This material is based on epoxy resin, polyethylene polyamine, hollow glass microspheres and gallium oxide. The use of hollow glass microspheres in the composition in an amount of 5-20 wt. h. reduces the dielectric losses, and the use of gallium (III) oxide in an amount of 5-15 wt.h. it makes it possible to increase the stability of the dielectric characteristics when working in the microwave radio range and reduce the dielectric loss. Studies have shown that a sufficiently effective composite polymer material with high physical, mechanical and dielectric properties can be obtained on the basis of the developed composition.
Keywords: composite material, epoxy resin, hollow glass microspheres, gallium oxide, permittivity, dielectric loss tangent