The article considers the results of a study aimed at establishing the constants of enzymatic kinetics of biological treatment of domestic wastewater in low-oxygen bioreactors of the circulating type and proposes methods for calculating such structures using the dependences of enzymatic kinetics Michaelis-Menten. The technological mode of operation of the reactor implies a total oxygen regime of not more than 1.1 mg / l at horizontal flow rates of 0.25-0.3 m/s. The efficiency of wastewater treatment is achieved by increasing the mass transfer of oxygen to the sludge mixture and directly into the flocs of activated sludge, as well as due to aerobic granulation by built-in secondary settling tanks.

Keywords: nitrification, denitrification, activated sludge, aeration tank, granular activated sludge, biological treatment, domestic wastewater, low-oxygen treatment method, energy saving, resource saving, ecology

An algorithm is given for carrying out repair work in rooms where devices with ionizing radiation sources are located (inspection points, X-ray machines, computed tomography devices, mammographs, etc.). All stages of the work are considered: the development of documentation, the conduct of examinations, the implementation of construction and installation works, the commissioning of the object (apparatus). Practical recommendations are given on the preparation of the required design and estimate documentation and repair work. The article was written on the basis of completed research work No. 20-147.

Keywords: construction and installation works, repairs, buildings and structures, ionizing radiation sources, X-ray machines, computed tomography devices, expertise

This work is devoted to the problem of the shortcomings of the current regulatory and methodological literature, which complicate the conduct of construction and technical judicial expertise. On the example of the building in Rostov-on-Don, the shortcomings of the normative and methodological literature in the areas of possible use of modern equipment for the inspection of structures are shown. This lack of the necessary normative literature in the field of non-destructive testing is clearly shown. This article shows the difficulties which experts face due to the indicated shortcomings. Conclusions based on the results of the study are made.

Keywords: cconstruction and technical expertise, normative literature, methodical literature, laser scanners, non-destructive control, masonry

An integrated information-measuring system is presented, which includes: a personal computer, special software, a set of sensors, an analog-to-digital and digital-to-analog converter, which makes it possible to investigate corrosion processes. Some possibilities of using modern information technologies in the workshop on physics and electrochemistry are shown. An experiment was carried out to study metal corrosion and its suppression using a traditional installation and a modified one using modern information technologies.

Keywords: software package, metal corrosion, natural experiment, integrated system, information technology

The article is devoted to the problems of the use of building waste in the demolition of houses, as well as substandard products at housing enterprises. The issues of concrete scrap processing, methods of its crushing to obtain materials that can be reused to create reinforced concrete products and structures are considered. Concrete scrap has been investigated for compliance with requirements for large aggregate for construction works. Compositions based on conventional coarse aggregate, concrete scrap and conventional fine aggregate have been developed. For the compositions, the technological characteristics of the concrete mixture are determined, as well as the physical and mechanical characteristics of the concrete at 28 days of age. The use of such compositions for the production of reinforced concrete structures is justified.

Keywords: concrete scrap, secondary crushed stone, concrete, characteristics of concrete scrap, recycling, construction waste, large aggregate from concrete scrap, application of concrete scrap

The article analyzes the experience of creating and testing a professional development program in the field of manufacturing products from micro-and nanopowders. The program is aimed at solving the problem of the qualification deficit experienced by powder metallurgy enterprises, which has become more acute in recent years The educational program was developed by the Volga State Technological University with the support of the RUSNANO Foundation for Infrastructure and Educational Programs and is designed to train engineering personnel in three areas: process engineers who develop technological processes for the production of powder products, design engineers - developers of technological equipment and production personnel who organize and control the production of metal powder products. A special feature of the program is its modular structure, which allows students to choose an individual learning path. The program includes a general professional cycle and three professional modules, the development of which allows you to form the professional competencies required by specialists. One of the modules is implemented remotely using e-learning technology. The advantage of the program is also a focus on practice: it provides a large volume of laboratory and practical classes, as well as practice at specialized enterprises. To assess the effectiveness of the advanced training program and if necessary to adjust it, the program was tested on a pilot group of students. Testing of the program confirmed its effectiveness and the possibility of successful use for professional development of specialists involved in the development and implementation of processes for obtaining products from metal powders.

Keywords: educational program of advanced training, production of powder metallurgy products from micro-and nanopowders, modular structure, distance learning, electronic training course, practice orientation, qualification deficits

The work is devoted to the search for an optimal design solution for columns of a 16-storey monolithic reinforced concrete residential building with a minimum cost of materials. The modern approach to the constructive solution of high-rise buildings assumes multipolarity at the design stage. Meeting modern requirements determined by human needs, durability and functionality of housing and other parameters, the essential importance of economic indicators is also noted. A special approach to the design stage as an attempt to consider in detail the preparatory stage (the choice of the section and class of concrete columns in buildings made of monolithic reinforced concrete) is justified by the relevance of the problem considered in the article.

Keywords: Reinforced concrete columns, frame calculation, Lira-SAPR, concrete class variation, optimal design of reinforced concrete structures, calculation of a 16-storey building

The key parameter of any cooling system is the heat transfer coefficient. The article deals with the issue of studying the dependence of the thermal resistance of the heat exchanger of a liquid cooling system based on ferrofluids and the heat transfer coefficient on the parameters of the fluid flow and the magnetic field in the heat exchanger. The study was carried out by numerical simulation and thermophysical experiment. A feature of the considered cooling system is the coolant. A ferromagnetic liquid based on Fe3O4 magnetites and propylene glycol is used as a coolant. As a result, a numerical model for calculating the heat transfer coefficient for an experimental liquid cooling system is obtained. The influence of the magnetic field on the thermal resistance of the system and the heat transfer coefficient of the wall-liquid at various magnitudes of the magnetic field strength is estimated. An experimental dependence has been obtained showing an increase in the heat transfer coefficient up to 12.5% when a magnetic field is applied.

Keywords: numerical model of heat transfer, liquid cooling system, Laplace equation, thermal management, CPU, ferrofluid, percolation, heat transfer coefficient, nanofluid, magnetic field, electronics cooling

The article discusses the effect of photon drag (EPI) of electrons in a semiconductor quantum wire (QW) with hydrogen-like impurity centers and Kane's dispersion law, located in a longitudinal magnetic field. An analytical expression for the drag current density is obtained in the effective mass approximation, and its spectral dependence is investigated for various values ​​of the magnetic field B and the parameters of the QW upon scattering by a system of potentials of short-range impurities. It was assumed that the QW has the shape of a circular cylinder, on the axis of which hydrogen-like impurity centers are localized. It is shown that, in the one-band approximation, taking into account the nonparabolicity of the dispersion law leads to significant dynamics of the threshold of the spectral curve. The spectral dependence is characterized by a pronounced Zeeman effect. The possibility of using an ESP for the development of photodetectors of optical radiation with a sensitivity controlled in a magnetic field is discussed.

Keywords: electron dragging by photons, quantum wire, hydrogen-like impurity centers, dragging current, dipole approximation

The global economy growth and active industrial development are limited, among other things, by the capabilities of existing technology. The potential for improving the functional characteristics of classical materials is practically exhausted, and the widespread use of new composite materials and high-enthalpy alloys is limited by the high cost and complexity of the technological process of their manufacture and processing. Knowledge of the materials physical-mechanical, thermophysical and chemical characteristics proves that the surface structural-phase state in many cases is crucial in the processes of wear, fracture, chemical and thermal destruction. Thus, the issue of developing technologies and equipment for modifying the surface layer and creating multicomponent coatings, including nanocomposite ones, is urgent. Current article presents the results of a study devoted to the creation of a facility for such coatings deposition by plasma spraying. One of the key elements of technological equipment for this method is a vacuum chamber, which is exposed to intense thermal stress during operation. Thus, the issue of designing a cooling system is relevant. To reduce the material and time resources at the design and experimental development, the temperature state of the chamber was simulated. It is shown that to ensure safe operation, it is advisable to use water cooling. The simulation results confirm the operability of the vacuum chamber cooling system under operating conditions. The following operating parameters were determined: the inlet pressure is 0.6 MPa, the water flow rate is 2 l/s, and the mass average temperature of the outlet water is about 40°C.

Keywords: plasma spraying, thermal state simulation, vacuum chamber, cooling system

Due to the constant increase in production, new structural materials development and growing rates of non-renewable resources consumption, the issue of increasing the machinery resource is urgent. Thus, it is necessary to develop technologies for spraying coatings that improve the functional characteristics of products, in particular, impact strength, microhardness, resistance to wear, corrosion and other environmental factors by modifying the surface layer structural-phase state. These technologies application is necessary in strategically important industries, such as machine tool manufacturing, aerospace, automotive, shipbuilding, chemical, energy, etc. This article is devoted to the facility development for multicomponent nanocomposite coatings sputtering. The design and commissioning of such a facility requires a high time and material resources investment. In this regard, it is necessary to use modern computer software systems that allow simulating multiphysics processes that take place during the facility operation. The simulation of the cathode-anode unit was carried out. Based on the simulation results it was shown that it is necessary to take into account the physical processes in the interelectrode region when designing the plasma spraying unit, since the resource of the cathode-electrode unit and the productivity of the sputtering process directly depend on the parameters of the discharge and the resulting plasma jet. Thus, high temperature and current density, as well as the arc spot abrupt movement, lead to increased wear and failure of the copper nozzles. The maximum values of the temperature and velocity of the plasma jet during spraying were 32000 K and 1800 m/s, respectively.

Keywords: plasma spraying, multicomponent nanocomposite coatings, multiphysics processes, mathematical modeling

Simulation modeling of protective circuits of a DC transistor electronic device is considered. It is shown that simulation modeling is one of the advanced research methods. The application of the Simulink program for this purpose is justified. The transistor switching device is considered from the point of view of overvoltages arising when the current is switched off. A simplified circuit of the switching device necessary for conducting research is given. A complete diagram of the Simulink model is given. Protection schemes using resistors, capacitors and varistors are given. The magnitude of overvoltages on a transistor with a different combination of protective circuits is investigated. The dependences of the overvoltage magnitude on the switched current for various combinations of protective circuits are given. The dependences of the overvoltage magnitude on the parameters of the elements of the protective circuits are given. The conclusion about the necessary structure of protective circuits is formulated.

Keywords: simulation, Simulink, switching device, overvoltage, transistor, protective circuit, varistor

Transportation is one of the most important stages in the management of cement delivery, which accounts for 60% of total costs. Thus, a slight improvement in the collection and processing of data on the operation of concrete mixers can have a significant impact on the overall savings spent on the work of companies engaged in transportation. On the other hand, the movement of heavy vehicles carrying cement mixture leads to the spread of air pollution and damage to the road surface in case of excessive loading. Therefore, the issue of determining the route of the vehicle to achieve this goal is very important. In this study, the routing process of concrete mixers was modeled using random routing problems and genetic algorithms. The simulation results showed that the genetic algorithm converges to the optimal answer. On the other hand, the volume of the cost function decreases from 1,177,500 rubles to 158,900 rubles. due to the optimization of the mentioned model, and the performance result led to the appearance of the shortest possible path. With the help of the algorithm, all the parameters of sustainable development management are achieved, including reducing air pollution, reducing fuel consumption and reducing the destruction of the road surface. Finally, thanks to the integration of the GLONASS/GPS software, the output data of the algorithm was mapped to the map.

Keywords: optimization of routes, fuel efficiency, reduction of emissions, preservation of the integrity of the road surface, optimization, logistics, modeling, special car, urban operation

The presence of vibration loads in any node or unit almost always leads to negative consequences in one way or another. Vibrations affect both biological objects and materials. High level of vibrations, under certain conditions can even lead to the destruction of the surfaces of parts and node as a whole. The purpose of these studies was to study the vibration-absorbing ability of zinc electroplating, used to restore the seating holes of the housing parts of machines. The main task was to determine the presence and the level of vibration-absorbing ability of zinc in relation to grey cast iron SCh18. The research was carried out on a laboratory prototype of a gearbox (gear reducer) with the use of vibration sensors and an oscilloscope. As a result, the vibration damping ability of galvanic zinc was proved and the comparative level of vibration damping in comparison with Cr18 cast iron was determined. For this study, zinc was electroplated from sulfuric acid electrolyte on the inner surface of the cast iron shells. First, readings were taken without zinc plating, then a 0.1 mm zinc layer was applied and readings were taken. After obtaining the data, the zinc layer was removed mechanically, the next 0.2 mm coating layer was applied and the readings were taken. The process was repeated with a coating interval of 0.1 mm until the zinc electroplating thickness of 0.6 mm was reached.

Keywords: load, vibration, vibration-absorbing capacity, electroplating, substrate, vibration velocity, vibration acceleration, oscillograms, sulfuric acid electrolyte, zinc coating, gray cast iron

This article is devoted to the study of concentrations of carbon monoxide (II), phenol, formaldehyde, aliphatic hydrocarbons in the premises of buildings, including the assessment of the regularities of their vertical distribution in the height of buildings at different times of the day from vehicles. Research is necessary to develop a program for electronic computers, which is necessary for the design of construction projects.

Keywords: помещения, оксид углерода (II), фенол, формальдегид, углеводороды алифатические, здания, время суток