The object of research is the design features of tanks for gas transportation in a compressed state and the criteria for their comparative evaluation. One of the most problematic places is the lack of a unified approach to the non-economic evaluation of the efficiency of transportation of compressed gas in high-pressure tanks. The issue is of particular importance in the conditions of gas transportation by sea and, in particular, produced on the shelf. This is due to the diversity of tank designs offered by manufacturers, characterized by different working pressures and design. To create the possibility of evaluation of the mass-dimensional perfection of high-pressure tanks, an analysis of the structures suitable for the formation of the cargo systems of marine vehicles, and the criteria for their comparative evaluation has been carried out. Also the design of multi-cavity high-pressure tanks of increased working tank is proposed. They consist of steel and fiberglass pipes and special connections with plug-in retaining elements. Considering that it is common to use normal cubic meters for gas metering, a new universal criterion is proposed for comparative evaluation of their perfection. It is determined by the ratio of the mass of the tank to the volume of gas transported in it to normal conditions. The criterion establishes the relationship between the amount of gas transported and the main parameter of the tanks, taking into account their inclusion in the freight systems of vehicles. According to the specified criterion, multi-cavity tanks are competitive in terms of their performance in the form of a lengthy design, limited by the parameters of the marine vehicle. Due to the universality of the proposed criterion, it is possible for manufacturers of high pressure vessels to use them in promoting products in various industries. For the perception of the new criterion by consumers, it is necessary to conduct its comparative analysis with the criteria used today for evaluation of perfection for tanks of various types and parameters.

The paper presents information on the prospects for the use of nanoparticles to improve the thermotechnical characteristics of heat exchangers of the refrigerator operating on isobutane. The effect of nano additives is considered on the example of an experimental study of an evaporator. The object of research is the refrigerator’s evaporator, working as part of the calorimetric stand. The parameters to which attention was paid in the experiment were the heat transfer coefficient and the heat loss coefficient. One of the most problematic places is the use of model manometers and thermometers, which required manual data removal. The problem can be solved by replacing analog devices with digital ones with constant parameter removal and automatic recording and processing by computer. It also took a long time to establish the regime. During the study, data were obtained that when using nanofluids as a working medium, it is possible to increase the heat transfer coefficient by 21 % at a mode with a boiling point of –20 °C and a condensation temperature of 40 °C and also by 18.1 % at the mode with boiling point –15 °?. The heat loss coefficient in the evaporator can be increased to 7.5 %. This is due to the fact that the proposed method of introducing impurities of titanium oxide into the working fluid of the refrigerator leads to an increase in thermal conductivity, and hence to an improvement in heat transfer in heat exchangers. The use of nanofluids makes it possible to significantly increase the heat and mass transfer characteristics of the refrigerant, as compared with the means that require structural changes in the refrigerator circuit, to reduce temperature differences on the surfaces of the condenser and evaporator. And as a result, to reduce the ratio of boiling and condensing pressures, and, consequently, the electric power consumed by the refrigerator without adding additional elements to the apparatus. The industries of rational use of these additives are enterprises and the production of low-capacity refrigerators, including household appliances.

The object of research is the process of creep feed grinding of parts of aircraft engines with hard-to-machine materials. In the aviation industry from such materials (steel 4?5??1?, ??53??????, etc.) blades and disks of turbines, segments of nozzle apparatuses, sectors of input guide vanes, plungers, pistons, gears, etc. similar details are made. Blade processing methods are not very effective in creating such parts. Increased wear of technological equipment and tools leads to an increase in temperature in the cutting zone, adversely affects the quality indicators and reduces the life of the product as a whole. Constant sharpening, editing or changing the tool to a new, additional adjustment of the process equipment leads to an increase in the cost of manufacturing parts from difficult-to-work materials. The introduction of creep feed grinding in technological processes allows to avoid the above negative factors. The increase in the technological modes of grinding reduces the processing time, but it becomes a cause of burn in the surface layers and damage to the processed surface. Experimental studies of the process of creep feed grinding are carried out to determine the temperatures in the subsurface layers of the part during its processing and subsequent comparison with the theoretically obtained results of the developed mathematical model. Processing was performed on a surface grinding machine Jotes SPD-30b (Poland). The temperature is measured by the contact method (measuring instrument ???? ??? 8, Russia) and contactless (using a pyrometer ?? 3M, Germany). The results of the experimental temperature values are given in tabular form. According to the research results, it is found that the use of a planetary grinding head for the technology of creep feed grinding of machine-building and aviation parts of difficult-to-process, corrosion-resistant materials leads to a decrease in the power-process parameters. In addition, there is an improvement in the surface cleanliness class (surface roughness Ra is between 1.25-1.8 µm). The results suggest that the technology of creep feed grinding should be introduced into technological processes instead of milling, external pulling and traditional grinding.

The object of research is AK7 alloy, which is subjected to the complex action of vibration and modification in the process of producing cylindrical billets by means of casting in a metal mold. One of the most problematic places is the determination of rational modes of influence of technological factors on the alloy, ensuring the satisfaction of a given level of properties in terms of their competitive nature. During the study, the methods of regression analysis were used and identified as promising methods of analysis of variance to improve the accuracy of the findings. In particular, the results of the regression analysis of experimental and industrial research data on the vibration treatment technology with a frequency of 100–150 Hz with an additional input of the ultradisperse modifier into the melt are presented. The results are obtained concerning the confirmation of the hypothesis about the significance of the influence of the modifier on the increase of the mechanical properties of the alloy: ??, s0.2, ss, ds, ?. This is important because attempts to improve the properties of the alloy using the combined technological solutions invariably cause the expenditure of energy and material resources. This ensures the possibility of energy and resource savings in the process. The obtained results show that the use of modification as an additional component of the technological process increases only ?, but reduces HB and ds. In the vibration frequency range of 100–140 Hz, modification has a positive effect on s0.2, and an increase in the frequency above this value leads to a deterioration in the result. The opposite effect is observed with respect to ds – with an increase in the vibration frequency of more than 140 Hz, modifying increases this alloy characteristic, in the range of 100–140 Hz, the introduction of a modifier can be considered justified. Thus, it is found that the modification has an ambiguous effect on the properties of the alloy, therefore, in order to select a rational technological regime, a solution to the compromise problem is necessary. This is due to the revealed fact of competing properties. It is proposed to use the methods of analysis of variance to refine the obtained results.

The level of electrophysical properties of fireproof polymer compositions, depending on the influence of ingredients, has not been sufficiently studied. This is especially true of the effect of the modifier on the properties of the insulation and sheath of cable products. Therefore, the object of research is the electrophysical properties of fireproof composite materials: ethylene-vinyl acetate copolymer, filled with hydromagnesite. Composition of the copolymer with a melt flow index of 2.5 and 5 g/10 min, hydromagnesite with an average median particle diameter of 1.4 µm, aminosilanes with a dynamic viscosity of 2 MPa·s and 2.5 MPa·s are investigated. An isolation test apparatus, an insulation resistance meter, an AC bridge are used. Electrophysical characteristics are obtained, which allow to determine the composition that provides the optimal values for insulating materials and materials of cable sheaths with increased fire safety requirements. The methods of electrophysical studies are used to determine the effect of the properties of the ingredients of polymer compositions on the electrical strength, specific volume electrical resistance, the dielectric loss tangent, and dielectric constant. Electric strength increases when using the polymer matrix EVA-1 and modifier 1 from 21 to 40 kV/mm; when using the polymer matrix EVA-2 and modifier 2 from 22.5 to 42 kV/mm. The specific volume electrical resistance increases significantly for polymer compositions filled with hydromagnesite, using the polymer matrix EVA-1 and modifier 1. Its value increases from 1·1013 to 6.6·1014 Ohm-cm. Using the polymer matrix EVA-1 results to reduce the dielectric constant. A significant decrease in this indicator from 4.1 to 3.6 is observed when using modifier 1 with a lower dynamic viscosity (2 MPa s). The tangent of dielectric loss angle also decreases from 0.013 to 0.0046 when using the modifier 1. It is advisable to use the results of the research to develop the composition of fireproof polymer compositions for cable products.

The object of research is the hydrodynamics of the boundary layer of the nozzle element of the proposed design. In the course of the study, computer simulation methods were used in the ANSYS environment, in particular the CFX block, which includes a set of physical, mathematical and numerical methods designed to calculate the characteristics of streaming processes. The analysis of the influence of the fluid velocity in the packed bed bioreactor on the magnitude of the hydraulic resistance for the following values of the fluid velocity: 0.1 m/s; 1 m/s; 2 m/s. The obtained data almost repeat the value of experimental studies, confirms the correctness of the construction of a computer model. A simulation of the hydrodynamics of a single nozzle of the proposed design for a longitudinal and transverse flow of fluid is done. Changes in the hydraulic resistance during transverse flow around the nozzle are insignificant, the maximum value lies within 101.3 kPa, for longitudinal washing the value of the pressure differential lies in the range from 98.96 to 102.7 kPa. Diagrams of the distribution of fields and velocity vectors in the boundary layer of the nozzle are obtained. When transversal washing of the nozzle, the magnitude of the velocities is in the range from 0 to 1.511 m/s, for longitudinal washer it ranges from 0 to 1.968 m/s. The distribution of the shear rate in the boundary layer is established, for the transverse washing of the nozzle, the magnitude of the shear flow rate ranges from 3.1 to 4.27·103 s-1, for a longitudinal washing of the nozzle, this indicator ranges from 5.6 to 1.25·104 s-1. Through the use of the proposed nozzle, it is possible to obtain large specific surface areas for the immobilization of microorganisms, provided that the critical parameters of the cultivation process are in accordance with permissible maximum deviations. Compared with the methods of determining the optimal parameters experimentally, a computer model is proposed that provides the following advantages: a significant reduction in the material costs of introducing a new nozzle design and a quick optimization of the process parameters when the initial data changes.

The object of research is calculation of the value of the course of changes in the internal temperature in the investigated house with ventilated (VPS) and unventilated enclosing structures, where the two-stage regulation of the operation time of the heat point was used. Complex analysis of energy efficiency of the house, and first of all, of the enclosing structures, has been carried out. It has been demonstrated that regulation of the central heating can be used for additional energy savings. It is also possible to regulate depending on the climatic conditions, that is, the thermal power of the boiler or the heating point will depend on the change in the temperature of the air outside. It has been established that the use of scientifically substantiated proposals offered in the work significantly increases the thermal inertia of the enclosing structures. Due to this, when the heating system is switched off, the house is slowly cooled and heated relatively quickly. Thus, it is possible to get savings, as the structure elements of the building accumulate heat. The essence of optimum temperature control has been established, which is controlling the supply of heat energy in the room in such a way that the corresponding internal air temperature has been reached over a certain period of time. It has been found out that in order to achieve high energy efficiency of a building, in addition to its thermo-modernization, it is necessary to maintain the appropriate climatic conditions inside the heating premises. The factors that influence the ability to regulate the temperature inside the premises, depending on the change in the temperature of the air outside, have been established. The coefficient of thermal accumulation of the building with the VPS use has been defined, which characterizes the ability of the overall structure of the building to accumulate heat and reduce the temperature fluctuations in the heated premises. In the course of the study, a technique for heating premises has been developed, which allows to determine the consistent change in the temperature of air in the premises. With the help of mathematical models developed in the work, it is possible to predict and optimize thermal processes in the investigated objects.

The object of research is the process of processing the signal of the primary converter by a certain method. In carrying out measurements on the primary converter of the measuring system, in addition to the action parameter measurement, there are many secondary influences. One of them is the change in the temperature of the environment. This leads to the appearance in the measured signal of such a component as an additional constant level. It is caused by the generation of the primary converter in the absence of influence on the object of measurement of additional charge, potential. That is, in the absence of action on the side of the measurement parameter there is a shift in the zero level of the signal of the primary converter. Thus the fluctuations of the temperature of the medium result in the appearance of a non-informative component in the measurement signal. That is, we get an increase in the error of the measurement result. The principle of the method used to process the signal of the primary converter is presented on the example of measuring the vibration with a piezoelectric accelerometer. The proposed method of processing the signal of measurement allows to distinguish a constant component of the complex signal of measurement. This is achieved by supplying a measuring signal to two parallel channels, in one of which the signal is delayed by phase for half of the period relative to the second, followed by processing on the adder. Since the signal from the primary converter has a wide frequency band, it is necessary to ensure the accuracy of the delay in the phase. This is achieved by reconfiguring a constant time phase filter phase. The reconfiguration is carried out using a frequency-voltage converter that tracks the frequency of the measured signal. Since changes in temperature over time compared with the frequency of measured vibrations are much slower, then the inaccuracy of the scheme is practically absent. That is, the inaccuracy of determining the constant component in the complex signal will be determined by the difference in the amplitudes of adjacent half-lives. The obtained results allow to assert that this method can be used both for correction of the primary transformer itself (by influence on its transfer function), and for correction of the results of measurements in general.

The object of research is a model of the thermal state of a remote measurement device, determined by the operating conditions and caused by the need to confirm the operation of the device in ambient conditions according to the requirements of the specification. During the research, the physical formulation of the problem of determining the thermal state of a remote measurement device under various operating conditions and their mathematical description were used. The choice of strategy is based on the solution of technological problems that ensure the optimal process of control. The thermal and mathematical model of the thermal mode of the device is developed to calculate the multidimensional temperature fields of the elements of the device. The model of the thermal mode of the remote measurement device is obtained. The proposed method allows to determine the temperature regimes of the nodes in the preparation mode and the main work at different ambient temperatures. In particular, determine the emitting power at the design state and changes over time. The model takes into account the geometric parameters of the main structural elements of the device. At the same time, in order to maintain the heat balance and the adequacy of the model to the main elements of the device, additional characteristics of these components are introduced in the mathematical model. So, the radiation heat exchange between the external surfaces of the device and the compartment structures surrounding it is taken into account. The regularity of changes in ambient temperature depending on the operation mode of the device is taken into account. The non-stationary thermal state of a remote measurement device is considered, taking into account the radiation-convective heat exchange of the external surfaces of the device with the environment. According to the conducted studies, the thermophysical characteristics of the materials used in the model are determined with two options of the temperature conditions of operation of the remote measurement device. The model is implemented in the STAR-CCM program code based on the control volume method. This technique simplifies the development of a numerical three-dimensional model from the control volumes of a remote measurement device for computer analysis. These studies are an integral part in the design, development and use of a remote measurement device based on a gyro sensor in various temperature conditions.