A computer mathematical model was developed to predict the course of working processes in the device. To estimate the reliability of the obtained model, the study of mass-exchange characteristics of the experimental cooling device was carried out. Analyzing the graphs of mass-exchange characteristics of the model and the experimental cooling device it is possible to conclude about their correspondence. The conducted tests allowed to reveal three characteristic zones of distribution of two-phase gas-liquid flows arising in the working zone of the atomizer at the atomizer's output in the steady-state operation mode. It is proved that the optimum air pressure at the inlet of the vortex chamber can be considered as 0.10...0.15 MPa.

Keywords: ejection, cutting zone cooling, mathematical model, dispersant, emulsion, aerosol, lubrication, turbulence, pressure, mass transfer, atomization

This article addresses a number of issues related to the environmental friendliness of motor vehicles. Modern trends in the transition of the market to electric vehicles, and the problem of recycling and recycling of electric vehicle elements are considered. It was revealed that the transition from cars from ICE to electric vehicles is not yet fully justified from the point of view of ecology.

Keywords: electric car, environmental safety, waste, battery, disposal, recycling

The article presents the features of the methodology for teaching general technical disciplines at an agricultural university, taking into account the reduction in the audience load when switching to the next standard of applied bachelor's degree of GEF BO 3. The work implements the approach of preserving classical methods and the volume of educational material both in standard (classroom form) training conditions and at the distance, by applying innovative educational technologies, in conditions of reducing the audience load.

Keywords: applied bachelor's degree, GEF VO 3 + +, competencies, educational technologies, general technical disciplines, independent work, remote technologies

This article is devoted to the study of indoor air quality in a higher education institution: assessment of the distribution patterns of suspended solids by equivalent diameters (RM0.5, RM1, RM2.5, RM5 and RM10).

Keywords: indoor air, indoor air quality, air pollution, dust, solid suspended particles, PM2.5, PM10

The article is devoted to the issue of improving devices for cleaning gas station emissions from hydrocarbon vapors to improve the environmental safety of zones and territories of residential development. The largest part of the release of gasoline vapors entering the local aspiration systems is associated with the filling and emptying of fuel storage tanks at gas stations. It is known that emissions of benzene vapors belonging to the second hazard class have a significant problem in terms of exceeding the maximum permissible concentrations at the boundaries of the sanitary protection zones of gas stations and nearby residential buildings. Creation of new highly efficient technologies and devices for reducing the volume of pollutant emissions from gas filling complexes, while reducing operating costs by the amount of emissions and waste generated, developing reliable gas trapping devices of acceptable low material and energy consumption for gas station aspiration schemes is an urgent task. Another reason of elaborations’ needs of those gas trapping devices are reducing operating costs and environmental payments for emissions and waste. It was carried out environmental – economic research to verify justification to use absorption-type apparatuses within an absorbent mixture of sodium-magnesium salt’s solution (bischofite solution) and waste water of from a local purification device. It was allowed reducing emissions from sources of gas station aspiration schemes using capturing gasoline hydrocarbon vapors by mention above apparatus. It is essential reducing negative emissions’ impact of harmful substances and an additional amount of generated waste of gas stations. There are presented the results of calculating volume of the fees’ environmental damage, and economic efficiency of the use the proposed type of sorbent’ apparatus in this article also. The use of the proposed device in gas station aspiration schemes allows deceasing environmental payments for emissions including carbon taxes and fees and additional operating costs in terms of the use of consumables. The successful tests carried out have shown the reliable and efficient operation of the pilot plant with the proposed device at the gas station. The successful tests carried out have shown the reliable and efficient operation of the pilot plant set up with the proposed device that decreased environmental payments for emissions, waste and operating costs.

Keywords: gas station, gasoline, emission, atmosphere, concentration, hydrocarbons, aspiration, absorption, device, bischofite, water

The article proposes a method for assessing the risk of a possible stay of an automated special-purpose information system in a critical state, based on the synthesis of two heterogeneous mathematical models, one of which allows taking into account the intensity of DDOS attacks and the intensity of application processing, based on Markov processes, and the second is one of the forms of a formal description of protection systems, with complete overlap, in which the interaction of the "threat area", "protected area" is considered – areas of resources of an automated information system for special purposes, and "protection systems" – security mechanisms of an automated information system. The developed method makes it possible to simulate the information security tools included in the automated information system for special purposes, under the influence of DDOS attacks, taking into account both the empirical values obtained as a result of measurements or modeling, and the theoretical base of parameters specified by input data. In the synthesis of the two models, the lack of uncertainty of some of the input parameters, taking into account the values based on expert estimates, was eliminated.

Keywords: automated information system, security assessment, queuing system, risk

The article is devoted to the use of artificial intelligence tools to solve technical problems in the construction industry. It is noted that the use of neural networks will allow taking into account the behavior of materials in various experimental conditions. The authors present a comparative analysis of approaches to neural network training, in particular, the structures of multilayer and LSTM networks are considered. It is established that LSTM networks are more effective in solving problems of identification properties of materials.

Keywords: neural network, non-destructive testing, identification task, multilayer network, LSTM network, impact indentation, indentation, strength properties of materials, neural network technologies, statistical distribution

This article analyzes the calculated fire curve in accordance with the ignition heat source in the compartment. To predict the calculated fire curve, the exponential equation proposed in the previous study was compared with the heat release rate measured in a fire experiment. The lag index, which is the main factor used to predict the time it will take to reach the maximum heat release rate, has decreased in proportion to the ignition heat source.

Keywords: fire calculation curve, pipe insulation, ignition heat source, deceleration index, heat release rate

In this article, we investigate the effectiveness of using multiple pipes for heat dissipation. The study assumes laminar flow under steady-state conditions. Various mixtures are numerically investigated at different flow rates. Various nanofluids flowing through multiple parallel pipes have been numerically investigated to study the effects of temperature rise. Thanks to the benefits they bring to the cooling process, nanofluids have opened up a new way to improve the performance of thermal systems. A typical nanofluid consists of a base fluid, which is usually water, and nanoparticles.

Keywords: heat exchanger, flow tube, nanofluid, bottom heating, coefficient of friction, pressure drop

The paper presents a comparative assessment of the methods for generating radiation in the form of a two and three-frequency symmetric packet of discrete frequencies, both traditional on the basis of the Mach-Zehnder modulator operating at various operating points, and the author's on the basis of tandem amplitude-phase modulation. The generated emissions are special cases of an ultra-narrowband packet of discrete frequencies used to construct radio-photonic vector analyzers. Based on the results of computer simulation of the shapers in specialized software, a qualitative and quantitative assessment of the purity of the generated radiation is given, which confirms the results obtained for mathematical models and their adequacy to the described physical processes.

Keywords: modulation of optical radiation, ultra-narrowband packet of discrete frequencies, Mach-Zehnder modulator, tandem amplitude-phase modulation, electroabsorption modulator

The paper presents the concept of constructing microwave photonic vector analyzers of a new type based on an ultra-narrowband packet of discrete frequencies, formulated as a result of a comparative analysis of existing methods for constructing optical vector analyzers.

Keywords: optical vector analyzer, microwave photonics, microwave photonic vector analyzer, modulation of optical radiation, ultra-narrowband package of discrete frequencies

This article presents the results of a study of the tendency of composites based on magnesium oxychloride cements to deformation changes. The dependence of the degree of deformation of light magnesian concretes on the conditions of their hardening has been determined. The main factors influencing the deformation of light magnesia concretes have been established. The influence of hardening conditions on the intensity of deformation changes is shown. Revealed the reasons causing uneven deformation of light magnesia concrete. A method for the manufacture of light magnesia concretes has been determined, which prevents their uneven deformation and subsequent violation of the geometry of the structure. It has been established that the introduction of modifier additives, such as cellulose ethers, helps to reduce the delamination of concrete magnesia mixtures, improve their homogeneity and reduce the unevenness of deformation changes over the sample volume.

Keywords: magnesium oxychloride cement, volumetric deformations, shrinkage, expansion, warpage, hardening conditions

Most of the electric motors used in industry are squirrel cage induction motors. In modern industries, various types of starting and controlling asynchronous motors are used, the choice of the starting mode determines the necessary means of automating the electric drive, which directly affects the functionality and, accordingly, the final cost of the project. Direct starting is the most common way to start an electric motor. The main advantage of direct start is the maximum cheapness of the control scheme implementation. The disadvantage of direct starting is high starting currents, exceeding the rated ones by 3-8 times, which leads to increased wear of the windings and causes a reduction in the service life of the electric motor. A high initial starting torque is accompanied by a significant impulse, which places a significant load on both the mechanisms of the electric drive itself and the units of technological equipment. Star-delta starting is used to reduce inrush currents. It allows you to make a soft start with a star circuit, and during operation, a triangle is turned on, providing the maximum power of the unit. In contrast to the starting modes discussed earlier, the soft starter stabilizes the starting characteristics, providing a gradual increase in power and stable operation of the motor, which allows to extend the service life of the electric motor and technological equipment. The use of frequency converters allows you to optimize production, reduce energy consumption, and increase the service life of equipment. The inverter also protects the electric motor in the event of a short circuit, deviations from the nominal mains voltage and controls the operating temperature of the electric motor, preventing it from overheating. Having considered the features, as well as the advantages and disadvantages of starting modes of asynchronous electric motors, it is possible to determine what equipment is needed to implement a specific task of an automated electric drive.

Keywords: automated electric drive, asynchronous electric motor, starting mode, soft starter, frequency converter, automatic control

The design of internal combustion engine (ICE) control system for an unmanned aerial vehicle (UAV), providing reduced fuel consumption and stable operation of ICE at an altitude above 5000 m above sea level, has been created. A system of remote adjustment of the internal combustion engine parameters in real time during the flight of the UAV was developed and manufactured.

Keywords: unmanned, aircraft, control system, internal combustion engine, remote adjustment, radio channel

The occurrence of convection in a two-layer system consisting of a region of a free fluid and a porous array saturated with the same fluid is investigated. The equations in the Oberbeck-Bussinesq approximation are used to describe the motion of a pure fluid, and the equations based on Darcy's law are used for the porous layer. Using the shifted grid scheme, the plane problem is approximated in natural variables. At the interface, special formulas derived by the integro-interpolation method and taking into account the different types of equations in the two domains are applied. The results of calculating critical numbers corresponding to the occurrence of convection for different heights of the porous layer and Darcy numbers are presented.

Keywords: dconvection, porous medium, Oberbeck-Boussinesq equations, Darcy model, shifted grids, stability