As the number of low-orbit satellite constellations (LEOs) increases, the probability of destructive impact from alien spacecraft (SC) will increase. One of the most effective impacts on the NHS is the setting of relay interference, which is an intercepted and delayed signal. This problem can be eliminated by using the "friend or foe" identification system for the spacecraft. At the same time, in order to reduce the probability of selecting the correct transponder signal by a foreign spacecraft, it is proposed to reduce the time spent on calculating the status of the satellite through the use of parallel calculations using codes of the polynomial residue number system (PRNS). A characteristic feature of these codes is the independent and parallel execution of calculations based on the bases of the PRNS. However, this property of the PRNS code can also be used to correct errors that occur during the operation of the identification system. In this case, the algorithm must perform this procedure at a lower time cost. Therefore, the modification of the error correction algorithm, which makes it possible to provide a higher speed of searching and correcting errors, is an urgent task. The purpose of the work is to reduce the time spent on the execution of the procedure for detecting and correcting errors during the operation of the identification system, by modifying the correction algorithm based on the Chinese residual theorem
Keywords: satellite identification system, codes of the polynomial residue number system, positional characteristic, error detection and correction algorithms
A review of methods for calculating microclimate parameters is performed. The possibility of using existing mathematical models to describe the aerodynamic characteristics of ventilation valves and optimize their performance indicators: productivity, hydraulic resistance, density, response time and other parameters that form their efficiency is considered. In order to assess the correspondence of the obtained mathematical dependencies, a physical experiment was conducted. The adequacy of the mathematical model was verified by comparing the results of calculating the parameters of the internal environment in the SolidWorks software and computing complex with experimental data.
Keywords: microclimate parameters, heat and mass transfer, mathematical modeling, heat transfer resistance, experimental study of microclimate, air mobility, valve
This work highlights the architectural and urban planning structure development of Rostov-on-Don in the first half of the twentieth century. The article reflects the main problems identified by architects in the 1920s and 1930s and attempts to solve them in the pre-war and post-war periods. The stages and conditions of restoration of the destruction of the city caused by two occupations during the Great Patriotic War are presented. The restoration concept of 15 RSFSR cities is described. The principles of restoration and their implementation on the example of Rostov-on-Don are considered. The evolution of the city’s architectural appearance is presented. The Triumph of Victory over the Nazi occupiers is shown.
Keywords: urban planning, restoration, architectural appearance, Rostov-on-Don, history of architecture, reconstruction, planning structure, general plan, urban landscaping structure, post-war restoration, preservation of architectural heritage
The article considers one of the ways to improve the reliability of mining equipment, by eliminating sudden failures and reducing the severity of their consequences, based on the use of digital technologies and automated control systems for its technical condition and online diagnostics. It is proposed to use the methods of diagnostics and automated control of the technical condition of power electrical machines, which consist in monitoring the current with subsequent spectral analysis of the recorded signal. The method allows to determine the current technical condition of the engine elements with sufficient accuracy. A high-performance RISC microcontroller of the AVR ATmega16 family was adopted as the constituent elements of the diagnostic complex, which contains a fast Harvard processor, program memory, data memory, input / output ports and various interface circuits.
Keywords: reliability of mining equipment, diagnostics, automated control, current monitoring, spectral analysis
The article presents the results of checking the adequacy of the method of online diagnostics and automated control of the technical condition of the electromechanical drive of the KP21 mining machine with an asynchronous squirrel-cage motor, proposed earlier by the authors. The method of experimental production studies provides for the connection of the measuring complex to the stator winding of one of the phases of the electric motor. The measurements were carried out under various operating conditions of the combine, corresponding to various technical conditions of the facility. A comparative analysis of the technical condition of the diagnosed nodes and the values of the normalized amplitudes of the corresponding frequencies led to the conclusion: the defect must be fixed if the signal amplitude exceeds the value of 10% of the maximum, and the defect is significant and needs to be eliminated if the amplitude value exceeds 30%. To use the obtained research results in practice, an integral nomogram of the correspondence between the operating time of the combine harvester and the amplitude - frequency characteristic of the stator current of the drive motor of the cutting body is proposed. The results obtained are taken as a basis for correcting the schedule of preventive maintenance and maintenance of the cutting body of mining machines KP21 when operating in the appropriate mining and geological conditions.
Keywords: reliability of mining equipment, online diagnostics, automated control, current monitoring, maintenance and repair
The article analyzes the peculiarities of the organization and technology of repair of urban roads in conditions of dense traffic. The technological parameters of pavement repair, considering uneven temperature and peculiarities of compaction of hot asphalt-concrete mixtures, have been substantiated.
Keywords: Urban roads, multi-lane highways, pavement repair, roadway, asphalt pavement, defects
The article considers the directions of development of energy, transport and water facilities through the use of liquefied natural gas.
Keywords: liquefied natural gas, energy, methane, motor transport
The object of the research is the utilization heat exchanger. The purpose of the work is to develop a design of a heat exchanger (HA) used to recover the heat of exhaust gases from a gas turbine unit (GTU) with an increased thermal power. In the process of work, the calculation and numerical modeling of the new design of the heat exchanger was carried out. The result of the research was the design of a gas-air heat exchanger, which requires 6.5% less flow rate of the coolant (exhaust gases) compared to the prototype.
Keywords: heat exchanger, heat utilization, energy efficiency of a gas turbine unit, numerical modeling, gas-air heat exchanger
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
This article considers the development of an information-measuring system for determining the thermophysical parameters of electrical devices. The developed functional diagram of the device is presented. Experimental studies were carried out in the COMSOL program. As a result of an experimental study of the transfer of heat from one part of the electromagnet to another, namely from the magnetizing coil, through the core to the environment, it was concluded that the best location of the temperature sensors is in the upper part of the body of the electromagnet EM-34-5. The data obtained can be used to determine the thermophysical parameters, in solving problems of the theory of inverse problems of heat transfer and heat transfer.
Keywords: information-measuring system, electrical devices, thermophysical parameters, COMSOL
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 article considers one of the parts of the development of the input control device for film capacitors. Structural and functional schemes have been developed. The results of modeling the measuring circuit in the Microcap software package are presented. The results of the model experiment confirm the correctness of the calculations.
Keywords: input control, film capacitors, Arduino, Microcap, diagnostics
A method of selecting admixtures for the production of dry building mixes is proposed based on the results of an expert assessment of the complex indicator of the workability of application (connectivity, continuity when pulling with a toothed trowel, elasticity, quality of rollers) on a 100-point scale and the strength of adhesion to the concrete base, followed by the calculation of the specific cost of admixtures in the mixture per ton of products, respectively, by one point of workability of application and 1 MPa of adhesion strength, developed as a result of studies of adhesive mixtures made using 4 different cements, 5 water-retaining additives and 12 redispersible polymer powders. The possibility of obtaining adhesive compositions of adhesion class C 2 using redispersible polymer powders of domestic production is shown.
Keywords: dry building mix, adhesion strength to the base, unit cost, processability of application
The choice of a method for transporting hydrocarbons from the shelf of the northern seas is an urgent task, necessary for the economic justification of a project for the development of an offshore field. A comparative analysis of existing transportation schemes allows us to take into account both the advantages and disadvantages of possible options, namely, the natural and climatic features of the region, the technical capabilities of contractor organizations, the cost of field development facilities and vehicle rental.
Keywords: hydrocarbons, continental shelf, transport scheme, analysis, tanker, gas and oil pipeline, onshore infrastructure, offshore infrastructure
The article is devoted to the problem of certification of construction projects according to new environmental standards in Russia and abroad. The main characteristics of foreign certificates BREEM, LEED, HQE and domestic "Green Standard", SDS "RUSO", EcoGreenOffice are presented; certification implementation processes; the main factors of green building. The problems of certification of real estate objects in Russia, as well as ways of solving these problems, are analyzed.
Keywords: certification, environmental standard, energy efficiency, green building, environment