Purpose of research. Analysis of preservation agents for the protection of technical products to determine the direction for the modification of preservation materials.
Methods. To achieve this goal, we have reviewed the modern scientific and technical literature in this area. The conservation method using lubricants is used to maintain the stored products in working order and use them as intended,. Lubricants for various purposes are usually subdivided into lubricants, oils and specialty liquids.
Results. The currently used preservatives not only fails to provide reliable protection of the materials of products, but in most cases they themselves are power sources for microorganisms, provoking the development of microbiological and corrosive damage. One of the new directions in the modification of preservation materials is the use of alternative sources for modification based on plant origin materials (essential oils). The conducted analysis shows that many of the foreseen means of conservation are not produced for objective reasons, and the use of other means is often ineffective. The solution to this problem is associated with the use of essential oils for modifying existing preservation materials. which should increase their protective properties against the effects of biodegradable microorganisms, and, as a result, create effective protection against corrosion and biological damage.
Conclusion. The presented results can be used to create resource-saving processing processes, frictional interaction, storage and preservation of metal systems, taking into account the operating conditions of a particular part for various weather conditions.

Purpose of research. With the increase of population and number of megacities, the consumption of various goods increases and the waste of which eventually turns into garbage. The growing amount of all kinds of waste every year and their negative impact on the environment is a global problem. However, with all existing methods of waste disposal, the least environmentally friendly method of waste disposal is used in our country - disposal by means of burial ground disposal at solid waste landfills. Landfills of solid waste are a source of landfill gas, the uncontrolled emissions of which have a negative impact on the environment. At the same time, the properties of landfill gas make it possible to use it as an energy source. The analysis of the problems рфму showт the relevance of the direction of using landfill gas as an alternative type of gas fuel, as well as the development of devices for its efficient combustion.
Methods. The article discusses the impact of solid domestic waste (MSW) on the Earth's biosphere. The analysis of the global problem of waste disposal is carried out, solutions are considered. Based on the methodology specified in GOST 33998-2016 “Gas household appliances for cooking. General technical requirements, test methods and rational use of energy ”, we have carried out a study of the efficiency of the landfill gas combustion process in the developed design of a gas burner device equipped with a thermal splitter.
Results. On the basis of experimental studies for a gas burner device of the developed design, the values of efficiency,% of the burner and the content of carbon monoxide (CO, mg / m3) in the combustion products have been obtained, depending on the length of the thermal divider.
Conclusion. The results of experimental studies have shown the high efficiency of the original gas burner device when burning landfill gas.

Purpose of research is to make methodology and algorithm for finite element modeling in a single computational scheme of deformation of flat steel trusses, previously stressed using high-strength ropes, in accordance with the chronology of impacts on the object in the form of prestresses, normative loads and emergency destruction of one of the bearing elements.
Methods. The solution of the problem is carried out in geometrically nonlinear staging using numerical integration based on Newmark approach with the construction of equilibrium equations of the finite element model of the structure in a deformed state at each integration step. Structural nonlinearity related to structural restructuring and consideration of ropes operation for tension only is described. The application of gravity forces of the carrier system, sequential introduction of tightening and their prestress, the application of payload and emergency impact in the form of instantaneous local destruction are traced. Before failure occurs, static loading condition is simulated using dynamic relaxation method. Methodology of accounting within numerical integration of emergency impact is formulated by application of dummy forces, values of which are calculated in excluded structural element before its destruction.
Results. Performance of presented computational procedure is illustrated by the example of a flat steel truss calculation with a span (54 m), including two ropes. Object behavior is considered considering the break of one of the ropes subjected to preliminary stress. It was revealed that the investigated emergency does not lead to the destruction of the second rope and the occurrence of plastic deformations in the truss rods.
Conclusion: Completed developments can be used to ensure the survivability of pre-stressed steel trusses under beyond design basis effects, leading to the destruction of individual structural elements.

Purpose of research. In some classes of information systems, it is impossible to use well-known algorithms for the identification and the authentication the data blocks sources. The reason for this is the duration of the full data processing cycle. The article considers the original algorithm for determining sources for a group of data blocks. It allows you to detect errors faster than the usual iterative algorithm for forming tree structures of blocks by changing the order of base operations. The purpose of the work is to reduce the computational and resource costs for the receiver to perform identification the sources of blocks, each of them has a size not exceeding a few bytes.
Methods. The identification method based on the forming a tree structure of incoming information blocks and subsequent analysis of tree branches. It allows selecting a chain of blocks formed by the target source. In the article the formal description of the algorithm is given. The results of the simulation of the procedures for determining the source are presented. In this case, the characteristics of the recursive algorithm were compared with those obtained for the known iterative one.
Results. The relationships between the average number of typical hash comparison operations, the average number of tree structure branches, and the number of accepted blocks obtained as a result of simulation modeling. This made it possible to determine the conditions for applying the recursive and iterative algorithms.
Conclusion. It is shown that the using of a recursive algorithm for forming a tree structure of frames can reduce the average number of base operations performed by the receiver by 5-10 % and reduce the memory cost for storing tree structure branches by up to 30%.

Purpose of research. The need for the development of a mathematical model for determining the composition of binary relations and a hardware-oriented algorithm for multiplying binary matrices that allow organizing parallel data processing when determining the composition of binary relations.
Methods. The procedure for determining the composition of binary relations is as follows: at the first stage, the definition of the sequence relation is performed, for this purpose its transitive closure is performed; the definition of the connection relation occurs after clarifying the sequence relation; then the alternative relation is clarified; at the final stage of determining the composition of binary relations, the parallelism relation is clarified.
Results. In this paper, a mathematical model for determining the composition of binary relations and an algorithm for multiplying binary matrices are developed. The novelty of the mathematical model is the introduction of binary relations of connection, alternative and parallelism of the vertices of flowgraphs of parallel algorithms in addition to the sequence relation known in the graph theory. The novelty of the binary matrix multiplication algorithm is the reduction of the number of iterations of the inner cycle (with respect to the variable k) when obtaining a single value at one of the iterations of determining the scalar product of binary vectors.
Conclusion. The developed mathematical model of binary relations of the sequence and connection of the vertices of flowgraphs of parallel algorithms allows for the organization of parallel data processing when determining the composition of binary relations. Based on the mathematical model for determining the composition of binary relations, a hardware-oriented algorithm for multiplying binary matrices was developed which allows transferring computationally complex procedures for multiplying binary matrices to the hardware level. The developed mathematical model and algorithm allow for the practical implementation of devices for multiplying binary matrices with an interruption of the internal cycle.

Purpose of research is of the paper is to analyze bifurcations of two-frequency oscillations of a DC electric drive with pulse-width control.
Methods. The research is based on the construction of a stroboscopic Poincare map, the calculation of saddle periodic orbits and their stable and unstable invariant manifolds.
Results. The study of the mechanisms of the occurrence of two-frequency oscillations from a periodic motion that loses stability in a DC electric drive with pulse-width control was carried out. A non-local saddle-node bifurcation leading to resonance (synchronization) on a torus characterized by a pair of independent frequencies when their ratio becomes a rational number, was studied.
Conclusion. A bifurcation analysis of the control system of a DC electric drive, the dynamics of which is described by non-smooth nonautonomous differential equations, was carried out. The research was conducted on an iterable map obtained from the specified vector field in an analytical form. It is shown that the system under consideration demonstrates two-frequency oscillations that occur through the Neimark-Sacker bifurcation. In the phase space of the discrete model, a closed invariant curve corresponds to oscillations with two independent frequencies. It is shown that if these frequencies are correlated multiply, then a resonance occurs when the dynamics becomes periodic. But at the same time, the closed curve remains invariant, and the limit points of the orbit form a pair of periodic cycles – stable and saddle, corresponding to a rational frequency ratio. A closed invariant curve is formed by unstable manifolds of a saddle cycle. If the frequency ratio is irrational, then the dynamics is quasi-periodic. The orbits of such motion fill the closed curve everywhere densely.

Purpose of research. Development of a technique for estimating the average flow rate of physiological fluids in capillaries from images obtained using laser speckle-contrast imaging. The technique includes obtaining experimental data in the form of an image of the fluid flow in a thin tube, their preliminary processing, including filtering and compressing data, as well as training and testing approximate models using modern machine learning methods.
Methods. The experimental study of the fluid flow in the tube is based on the application of the laser speckle-contrast imaging method. The spatial speckle-contrast values are calculated from the obtained images. The obtained data are subjected to preliminary processing, including the data filtering out and extending to a steady flow mode, as well as compressing the obtained images using the principal component method, which allows reducing the dimension of the feature space. The problem of predicting the average velocity from the image of the fluid flow is solved as a classification problem based on the composition of decision trees constructed through the bagging procedure, as well as in the form of a random forest.
Results. A technique for predicting the average velocity of liquid flow in a capillary from images obtained using the laser speckle-contrast imaging method has been developed. The accuracy of predicting the average velocity (or flow rate) based on the training sample was about 91%, on the validation and test samples - at least 81.5%.
Conclusion. Based on the developed technique, it is planned to determine the kinematic characteristics of the parameters of physiological fluids flow, which will improve the inertial method of measuring the viscosity of the tested liquids developed earlier by the authors, getting rid of a number of assumptions about the velocity profile.

Purpose of research is to describe the process of making managerial decisions in terms of the management system of logistics flows based on the management theory principles and concepts.
Methods. The formalization of the management system of logistics flows of transportation and storage complex is based on the management theory approaches and methods. The proposed management system model presupposes the formation of an influencing impact, the specification of the output coordinates of the object under control after working out control actions, and a description of the external environment. The visual model of the management system and its formalization in terms of the set-theoretic approach are presented. Management principles based on error and disturbance are described; the accounting of these principles makes it possible to adjust the managerial actions on the logistics flows of the transportation and storage complex to achieve the targeted benchmarks of a company. Making a managerial decision in logistics of transportation and storage complex is based on a process approach.
Results. The proposed visual as well as set-theoretical model of the management system for logistics flows of transportation and storage complex is the basis for further formalization of the management problem, optimality criteria and corresponding constraints in similar logistics systems. The process of managerial decision-making in relation to logistics flows given in the article is considered as the basis for expanding the possibilities of applying automated decision support systems.
Conclusion. The prospects for the further development of management processes based on the principles of automation are assessed as significant ones. The theoretical substantiation of these prospects is the formalization of the control system model based on the management theory approaches, which makes it possible to determine the areas of further work for expanding management theory use in such organizational systems as logistic ones as well as to specify the management task for them.

Purpose of research: Development of a neural model of a semiconductor gas sensor in order to generate data for training an information-processing device of gas analyzers based on artificial neural networks (ANN). Search and optimization of cleaning data composition and volume. The neural model of the sensor should take into account the influence of those factors on the signal, the fluctuations of which make the maximum contribution to the measurement errors. Testing of the model based on semiconductor carbon monoxide and hydrogen sensors.
Methods. Methods of computer modeling, numerical methods, theory of neural networks. To compare the simulation results and the responses of real sensors, the relative error and standard deviation were determined.
Results. Studies of various structures of the neural model of a semiconductor sensor have been carried out, the structure of a multilayer neural network of direct propagation for two semiconductor carbon monoxide and hydrogen sensors has been selected, modeling errors have been estimated, recommendations have been given for choosing the optimal structure and the amount of training data.
Conclusion. Neural models of semiconductor carbon monoxide and hydrogen sensors have been obtained, conclusions have been drawn about the possibility of using this ANN structure in solving typical problems. Based on the analysis of the errors obtained, the effectiveness of using neural models of sensors to generate training data has been shown. The maximum relative error of modeling the TGS2442 semiconductor carbon monoxide sensor did not exceed 5% for the main characteristic and 2% for additional ones. The maximum relative error of modeling of the TGS2442 semiconductor hydrogen sensor did not exceed 3% for the main characteristic and 1% for additional ones.