An urgent scientific and technical task is the development of electric energy converters with high operational and energy characteristics. The use of modern methods for the development and analysis of power electronics circuits based on the use of computer equipment allows us to successfully solve this problem. In this article, a schematic diagram of an alternating voltage regulator has been developed, in which a control system based on a microcontroller implementing an algorithm for pulse-phase regulation of the variable output voltage is used to control a power thyristor key. The control system, a power thyristor key, is synchronized with the moments of transition through zero of the supply voltage of a sinusoidal shape. The controller circuit is adapted for computer modeling in the environment of the PROTEUS software product. In the article, a block diagram is also developed and a software implementation in assembly language of the microcontroller operation algorithm is performed. As a result of computer modeling, time diagrams of voltages on the main elements of the AC voltage regulator circuit are obtained. Time diagrams explain the features of electromagnetic processes occurring in the controller circuit. The results of computer modeling, the controller circuit, the developed algorithm and the microcontroller software can be used in the development of electric energy converters for automatic control systems of electrical equipment.

Keywords: computer simulation, thyristor regulator, alternating voltage, microcontroller operation algorithm, time diagrams, transistor switch, control system, damping circuit, power thyristor, active-inductive load

The paper considers mathematical models obtained on the basis of experimental studies of electrical sheet steel. The models reflect the error in determining the main magnetization curve of electrical steel. The magnetic properties are determined in the center and at the edge of the cut of sheet samples with a size of 150 × 150 mm, made by cutting with guillotine shears and laser cutting. The choice of scale factors for calculating the main magnetization curve with an error of ± 5% according to the measured Weber-ampere characteristic has been substantiated. The study was carried out using a device for express control of the magnetic characteristics of electrical sheet steel. The main curve of magnetization of the sample material from sheet electrical steel was determined in an alternating magnetic field with a frequency of 50 Hz, along the direction of rolling. Investigated samples of isotropic sheet electrical steel grade 2212.

Keywords: mathematical model, electrical steel, magnetic properties, magnetization curve

This paper proposes an algorithm for automatic segmentation of subretinal fluids in the macular retinal layers of the retina. The proposed algorithm is implemented in an integrated development environment - PyCharm, a high-level general-purpose programming language (GPL) - Python was chosen. The proposed algorithm together with other methods of analysis of morphometric parameters of the human retina, which are still under development, will be used for more accurate diagnosis of the stage and degree of retinal damage in age-related macular degeneration.

Keywords: software, image processing, diagnostics, automatic segmentation, macula, retina, age-related macular degeneration, optical coherence tomography

The article provides a brief overview of the creation of the Diagrid system, describes the concept of forming this structure, its key elements and their role in creating geometrically immutable integral structures. The main directions of application in construction and the peculiarities of work on vertical and horizontal force effects are given. It also provides an overview of the materials of construction used and the main design constraints. This article will be useful for design engineers and architects engaged in the design and calculation of high-rise buildings, as well as buildings with a complex architectural form made of reinforced concrete and metal structures.

Keywords: diagrid, mesh supporting structures, reinforced concrete structures, metal structures, stability, free architectural form

The main types of formwork systems used in monolithic construction are described. The types of formwork by construction, by the type of concreted structures, by the base material, by turnover, as well as the types of formwork during concreting under different temperature conditions are considered. The historical reference of the appearance of the formwork is given.

Keywords: formwork, frame-monolithic construction, structures, vertical, horizontal, large-panel, small-panel, block, volume-adjustable, heating, inventory formwork

The article deals with the forecasting of direct material damage to urban areas depending on the number of fires based on official data of the Ministry of Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters, presented in state reports on the state of protection of the population and territories of the Russian Federation from natural and man-made emergencies for five years, based on the model of correlation analysis, which allows us to determine the degree of mutual influence of the parameters under consideration and the linear regression responsible for determining trends for subsequent years. The analysis of the reasons associated with the lack of the possibility of assessing the damage resulting from the fire of the structures of the building or its premises and its subsequent extinguishing in order to increase the economic efficiency of the cost examination during the restoration of real estate is an auxiliary basis for the construction of a correlation-regressive forecasting model.

Keywords: fires, cost assessment, cost of restoration repairs, real estate objects, economic efficiency, statistics, direct material damage, correlation and regression analysis

a study of a ventilation system with a local recirculating diffuser was carried out. A three-dimensional model of the office space has been built. Using the STAR-CCM + hydrodynamic computing complex, a numerical simulation of the ventilation system has been performed. The calculation results are analyzed, the advantages of the investigated system are given.

Keywords: ventilation systems, local recirculating diffuser, indoor air quality, energy saving, numerical simulation, STAR-CCM +

As the object of research, the angular joints of glued wooden structures used for the construction of external enclosing structures in low-rise housing construction, made in factory conditions with modern equipment, were selected. As part of the work, the available literature on this topic was analyzed. The analysis of the variability of the use of modern corner joints of external walls for low-rise construction, made of glued beams, in the design and construction, taking into account the development of technical capabilities in modern industries. Describes the old and new device technology, corner joints, indicating the advantages and disadvantages of such compounds, describes the technical characteristics of the used elements. Conclusions are drawn, as well as recommendations for the further use of these materials in design and construction.

Keywords: glued wood, structural features of corner joints, production of wooden structures

The article reproduces and supplements the experience of modeling and determining the optimal angle of inclination of the lattice with an estimate of the total lengths of the elements, the greatest forces, displacements and natural frequencies for computer models of various configurations. The possibility of using this system in civil construction with the use of volume-block technology of building construction is described. This article will be useful for design engineers involved in the design and calculation of high-rise buildings, bulk-block or modular buildings made of reinforced concrete and metal structures.

Keywords: diagrid, mesh load-bearing structures, reinforced concrete structure, metal structures, stability, computer model, high-rise buildings, bulk-block, prefabricated module

Based on the Bayes approach, a representative number of experimental measurements was determined when assessing the quality of the environment, in particular, when monitoring the quality of the atmosphere and checking the compliance with the standard for the accumulation of solid municipal waste

Keywords: Bayesian approach, quality control, experimental measurement, a priori data, a posteriori data, distribution density

The purpose of this work is to develop an algorithm for recognizing shrinkage defects on metal alloys. The steps for image processing are described. When analyzing the algorithm, a description is presented for each step, followed by a software implementation. The final step, after using the methods of the algorithm, is to count the contours of the defects. To demonstrate the functionality of the software, random photos of the metal body in the section were taken, where defects in the form of gas pores can be directly observed. The software, with the correct selection of input data, processes the image with high accuracy, minimizing errors in calculating defects. Using the proposed algorithms reduces the diagnostic time. The article presents a comparative description of the manual and automated methods, showing the effectiveness of the second method in comparison with the first. To write the software, the Python 3.7 programming language was used, as well as the OpenCV computer vision algorithms library.

Keywords: defect detection, computer vision algorithms, OpenCV, metal defects, shrinkage defects

Reducing energy consumption in the design, installation and operation of engineering networks is implemented in the process of implementing investment construction projects. An energy service contract, like any economic agreement, requires a feasibility study. When strengthening the thermal protection of a building, it is necessary to determine both the design of the fences and translucent structures, and the payback period of the investment. The objective of the research is to develop and analyze a mathematical model of heat losses depending on the characteristics of the resistance to heat transfer of walls, windows and balcony doors. Classical dependencies do not allow applying standard mathematical analysis procedures. It is proposed to use a power function that assumes the availability of differentiation. The paper substantiates the form of such a function and provides an extended analysis of the effect of changes in the resistance to heat transfer of building structures on the transmission heat losses of a building, which allows arguing for the adoption of optimal technical and economic decisions.

Keywords: energy-saving construction project, thermal protection of buildings, indifference curves, mathematical model of heat loss

For the statically indeterminate systems under consideration, there is an optimal ratio between the load-bearing capacity of stretched and out-of-center compressed elements, in which the required reliability will be provided at the lowest value of the mathematical expectation of an external destructive load. It should also be noted that for statically indeterminate systems, the beginning of rebar fluidity is not a sign of destruction, but only indicates the beginning of an intensive redistribution of forces in it. Therefore, the values of C, do not refer to the beginning of the rebar flow, but to the complete exhaustion of the load-bearing capacity. The reliability of statically undetectable systems, including prestressed trusses, is always higher, all other things being equal, than that of statically definable systems.

Keywords: reinforced concrete, reinforced concrete structures, statically indeterminate systems, reliability

A method for determining the optimal value of the heat transfer resistance of a three-layer exterior wall of a country cottage building is presented. As an optimization criterion, the specific consumption of thermal energy for the weekly cycle of operation of the building is selected. As a result of the study of the function describing the total specific energy consumption for heat loss compensation and heating of 1 m2 of the outer wall, an analytical expression was obtained to determine the optimal value of the heat transfer resistance. Based on the obtained solution, the thickness of the monolithic expanded clay concrete used as a structural and thermal insulation material in the outer wall is optimized. An analytical relationship is obtained to evaluate the energy-saving effect due to additional insulation of the outer wall of a country cottage.

Keywords: intermittent heating, heat transfer resistance, enclosing structure, energy consumption, heat protection characteristics

The object of the research, the result of which is the presented work, is a comprehensive system of spatial data of the railway infrastructure, within which a high-precision system of coordinates of the Russian Railways has been created, and methods definition of normal heights in the Baltic Heights System 1977. The strategy and prospects for the development of high-speed transport highways (VSM) have been described. Methods for determining normal heights at research sites are given.

Keywords: monitoring, buildings, facilities, engineering and geodesic research, laser scanning, GNSS receivers, design, construction, observations, geodesic measurements