Objective. The objective of the study is to increase the reliability of the contact of the semiconductor transistor crystal to the body and the reproducibility of the technological process.

Method. A method for obtaining multilayer metallization of the reverse side of the crystal has been developed and the most optimal technological modes of its formation have been selected. The parameters of the reliability of the connection of the crystal to the body of the transistor were checked.

Results. Layer-by-layer metallization has been obtained, which provides a strong contact to the collector region of the transistor and a reliable fit of the crystal to the base of the case.The control of technological operations showed 100% distribution of solder over the surface of the crystal, the absence of pores in the solder, the improvement in the output characteristics of the device and the increase in the percentage of output usable transistors.

Conclusion. An analysis of the experimental results showed that in order to create a reliable contact and remove heat from the collector junction of power semiconductor transistors on the reverse side of the plates, it is necessary to form a metallization in one technological cycle, consisting of four layers of metals (Cr-Ni-Sn-Ag). The technical result of the research is to improve the quality of fit by obtaining a uniform distribution of the layer of Cr-Ni-Sn-Ag metals in a single technological cycle.

Objective. The purpose of the article is an experimental study of a thermoelectric system (TES) for the treatment of periodontal diseases by the method of local hypothermia.

Method. An experimental stand and a technique for measuring prototypes of TEC for the treatment of periodontal diseases by the method of local hypothermia are described. The experimental stand is made on the basis of the measuring equipment of the laboratory of semiconductor thermoelectric devices and devices of the FSBEI HE "Dagestan State Technical University". In the first version of the TES, two thermoelectric modules (TEMs) are directly mated with the simulator of the periodontal area through a silicone layer, and in the second, thermal contact between the thermomodule and it is made through a special highly thermally conductive nozzle.

Result. Graphs of the time dependence of the temperature change of the control points of the experimental samples of thermal power plants for the treatment of periodontal diseases by the method of local hypothermia at various TEM supply currents were obtained. The control points were the cold and hot junctions of the TEM, periodontal simulator, heat sinks from the hot junctions of thermal modules.

Conclusion. As a result of the measurements, it was found that it is possible to achieve the required level of decrease in the temperature of the periodontal area using standard TEMs of the Kryotherm LLC (St. Petersburg) type TV-17-1.4-1.15 and DRIFT-1.2. In this case, the duration of the output of the samples to the regime in the first case is 230 s, and in the second - 320 s. The deterioration of the dynamic characteristics of the second version of the device is associated with the presence of a highly thermally conductive nozzle. As a result of full-scale tests, it was shown that the use of forced air and liquid cooling to remove heat from TEM hot junctions is sufficient to comply with the required temperature regimes of hypothermia.

Objective. The aim of the work is to study the use of nanofluids as heat carriers to increase the efficiency of heat removal in energy facilities. To solve this problem, materials of domestic and foreign scientific articles, conferences and dissertations on the subject of nanofluids were analyzed. Numerous scientific publications, including those cited in the international databases Web of Science and Scopus, indicate that the topic of nanofluids is in the focus of modern science. However, despite a rather long period of fluid research, not all issues of this topic are sufficiently well covered and systematized, which opens up great opportunities for further research in this direction.

Method. When achieving this goal, the areas of possible application of fluids, the mechanism of their synthesis, the features of their operation are considered, the advantages as a liquid coolant are indicated, and the disadvantages that prevent their widespread use are identified. Particular attention is paid to such issues as: synthesis of standardized nanofluids; ensuring their stable properties; the use of surfactants; increasing the pressure drop inside heat exchangers during operation of this coolant.

Result. To eliminate the main drawback in the form of agglomeration of nanoparticles in the base fluid, it is proposed to use the oscillatory circulation of the coolant, which will also further intensify heat exchange from forced turbulence of the fluid.

Conclusion. The results obtained can be used to improve the efficiency of heat and mass transfer devices with liquid coolant and systems based on them, as well as to reduce the weight and size parameters of such devices.

Objective. The aim of this article is to develop a program for approximate estimation of regression models specified on the basis of the Leontief production function (non-elementary regressions with two variables) and use it for modeling the unemployment rate in the Irkutsk region.

Method. Estimation of non-elementary regressions is carried out using ordinary least squares method. To find approximate estimates, we used a previously developed algorithm that involves solving a very laborious computational problem.

Result. Based on this algorithm, a special program was developed in the Delphi programming environment. The program provides for work in manual and automatic modes. In manual mode, according to the specified criteria, the estimates of the model parameters, the residual sum of squares, the coefficient of determination, the Student's criterion, Durbin-Watson's criterion and, for each variable, the number of the binary operation components triggerings on the sample, are determined. In automatic mode, the best estimates of non-elementary regression are determined according to the criteria: residual sum of squares, coefficient of determination, the Student’s criterion and Durbin-Watson’s criterion. At the same time, graphs of all the main characteristics are plotted depending on the key parameter of the model. With the help of the developed program, a model of the unemployment rate in the Irkutsk region was construct.

Conclusion. The model construct using the developed program turned out to be better than the traditional model of multiple linear regression. The program is universal and can be used to solve specific applied problems of data analysis.

Objective. The aim of the study is to develop a mathematical model for assessing the stability of the functioning of an informatization object (IO) in the conditions of computer attacks (CA), assuming that the laws of distribution of random variables before the enemy's impact and the recovery time are distributed exponentially.

Method. Application of the method of discrete Markov processes to solve the problem of assessing the stability of IO, which differs from the known approaches in that to describe the state of IO, the concept of "non-returnable state" is introduced, into which the system can move due to the exhaustion of the resource allocated to restore its readiness after a successful CA.

Result. As a result of the research, a mathematical model has been developed that allows us to build the stability function of the IO taking into account the intensity of the CA flow and the intensity of restoring its operability, taking into account the limitations on the allocated resource.

Conclusion. The application of the method makes it possible to quantify the stability of the functioning of the IO by constructing the survivability function of the IO for conditions under which the flows of attacks and recoveries cannot be assumed stationary and ergodic, and there is also no representative statistics for calculating asymptotic estimates of stability. A quantitative assessment of the stability of the IO for the conditions of the CA is in demand by information security management bodies when making decisions to ensure the protection of information, as well as when justifying the requirements for the system to restore operability.

Objective. The article discusses hardware and software methods of protecting the resources of the personal data information system from unauthorized access by means of "sniffing attacks"; the essence of which is to intercept data that is delivered within the observed system in the form of packets.

Method. The analysis of the security of resources by the personal data information system regarding unauthorized access to data by means of "sniffing attacks" includes five conditional stages: collecting information in the personal data information system, scanning the personal data information system, gaining access to the personal data information system, securing personal data in the information system, generating a report; at the same time, security analysis it is always associated with unauthorized access to data.

Result. To prevent unauthorized access to data by means of "sniffing attacks", the following software and hardware solutions are proposed to minimize the consequences of unauthorized exposure to the personal data information system: the use of the HTTPS protocol, a secure version of the HTTP protocol; the use of a static ARP table generated manually; scanning of the computer network of the personal data information system by the AntiSniff program; encryption of the computer network traffic networks of the personal data information system.

Conclusion.The presented hardware and software solutions allow minimizing the consequences of unauthorized impact on personal data information systems.

Objective. Network security systems are one of the key players in today's business life. Some networks are private while others are open to the public. Whether your network is private or public, it must be well secured and secure. In this article, we will discuss where network security begins, and describe the general measures taken to secure it.

Method. The study is determined by the need to solve the problem of algorithmic and mathematical support for assessing the functional security of a network based on system modeling and finding erroneous positions.

Result. Proposed deployment of a private network system that is designed and serves a specific group of people for communication, collaboration and sharing.

Conclusion. The proposed methods can be effective in protecting the network from attacks and other security threats. Well-designed corporate policies are critical to defining and controlling access to various parts of the network.

Objective. The purpose of this work is to optimize the functioning of the automated control system of the heat supply system. The connection between the flow rate of flue gases at the inlet to the waste heat boiler and the temperature of the heat carrier at the far point of the consumer is subject to adjustment.

Method. The methodological basis of the study is: the heat balance equation for the waste heat boiler of the combined cycle plant; principles for ensuring the specified parameters of heat supply to the consumer; equation of heat and mass transfer and sanitary standards for heat supply.

Result. A mathematical apparatus has been developed that expresses the dependence of the flue gas flow rate at the inlet to the waste heat boiler and the temperature of the coolant in the heating device in the farthest room of the analyzed building.

Conclusion. Optimization of the automated control system of the heat supply system on the example of a building of a higher school shows the possibility of improving the accuracy of control of the automated control system by the heating system. In the case of an additional installation, the narrowing of the error corridor occurs by 2.5 times.

Objectives. Structuring of publicly available information to identify the distinctive features inherent in state corporations of the Russian Federation and to describe the threats arising as a result of their continuous operation.

Method. The following methods of scientific cognition are used: systematization, description, analysis, deduction. The characteristics of state corporations are formed on the basis of data obtained both from the regulatory framework and by means of analysis of modern research in the field. In the future, the systematization of knowledge about the threats of state corporations is carried out, the most common classifications are considered, the increasing activity of intruders regarding critical information infrastructure objects is noted, and possible consequences for the state corporation after a successful computer attack on them are noted.

Result. In this paper, a study was conducted on a little–covered area in the scientific literature - the protection of Russian state corporations. A comprehensive analysis made it possible to characterize the object of research in detail, thereby specifying the significant aspects of its functioning. Next, the most significant threats of Russian state corporations were shown, the importance of ensuring information security was noted and 15 factor influences of a successful cyberattack were shown.

Conclusions. The conducted research is of an overview nature. The materials presented in the paper can serve as a basis for further research in the direction, as well as the formation of principles of protection against the mentioned threats.

Objective. The purpose of the work is to develop universal logistics approaches to modeling the optimal supply chain management system in the conditions of a multimodal service center.

Method. The methodological basis of the study is theoretical and experimental research in the field of creating an effective model of supply chain management in transport systems.

Result. A process approach to the strategic management of supply chains for the logistics of transport systems has been formalized, taking into account the influence of a group of factors; developed a methodology for managing relationships with suppliers, taking into account their integration in supply chain management; rational parameters for evaluating the effectiveness of the logistics management system for logistics under given working conditions were determined; a methodology has been developed for managing supply chains of logistics in the conditions of operation of a multimodal service center based on the application of the theory of experiment planning.

Conclusion. Optimization of supply chain management (Supply Chain Management, SCM) allows you to effectively plan, form, control and regulate material, financial, information flows throughout the entire life cycle of goods. The resulting regression equations are recommended to be used as a mechanism for analyzing the work with the selected supplier when organizing the optimal management of supply and procurement processes in the transport system in the conditions of operation of the multimodal service center of GRAND MOTORS LLC.

Objective. A characteristic feature of the current stage of development of the sphere of informatization of internal affairs bodies (OVD) is a significant increase in the volume and variety of types of service information of limited distribution, stored, processed and transmitted in automated systems (AS). This gives rise to the emergence of a large number and expansion of the range of threats to information security, primarily threats associated with unauthorized access (UAS) to the information resource of the ATS AS, and necessitates the improvement of existing methods to combat this type of crime in order to ensure the information security of objects of informatization of ATS. To obtain information that allows assessing the degree of threats, it is necessary to conduct a quantitative risk assessment.

Method. The method for assessing the risks of implementing threats of unauthorized access to the information resource of the ATS AS and obtaining data in a quantitative representation is based on the use of mathematical modeling methods. The advantage of a quantitative assessment compared to a qualitative assessment is the ability to compare risks with the final result, which can be represented in monetary terms, and further use in assessing the likelihood of information threats and calculating the damage caused.

Result. A methodical approach to the quantitative assessment of the risks of the implementation of UA threats to the information resource of the ATS AS is proposed, which makes it possible to assess the level of security of service information.

Conclusion. The proposed methodological approach to quantitative assessment of the risks of the implementation of UA threats to the information resource of the ATS AS provides a visual representation in monetary terms of the objects of assessment (damage, costs). These calculations can be used to justify the requirements for the level of security of ATS ASs during their development and operation.

Objective. The aim of the study is the mathematical support of the vacuum microwave process, the design of the installation in CAD, the manufacture of a prototype, the modeling of temperature and moisture content fields.

Method. The mathematical model was implemented numerically by the finite element method in the Comsol Multiphysics environment on a grid of 3678 elements, using its deformation to change the height.

Result. Experimental data were obtained on a laboratory vacuum microwave installation, which made it possible to identify patterns in the drying of foamed materials. The drying parameters, as well as the properties of the initial and dried material, were analyzed. A pilot-type vacuum plant was designed using CAD and a working prototype was made. The modeling of the temperature field and moisture content zones in the dynamics of the process has been carried out.

Conclusion. Mathematical modeling of the drying process makes it possible to determine the temperature fields and moisture content of the material with a high accuracy with a relatively small amount of necessary experimental data.

Objective. In the design of complex engineering structures, the problem of stability is now becoming especially relevant. With the need to meet the conditions of strength, rigidity in calculations and design, it is imperative to ensure the stability of equilibrium as the most important requirement. Regardless of the type of strength calculations (verification, design, load), the calculation of a structure for stability, even in the simplest formulation, is reduced to the determination of critical forces. This allows us to estimate the stability margin of the structure under a given load. The complexity of determining the critical parameters of the impact increases with the complexity of the system under consideration.

Method. The use of the finite difference method is a feature in solving systems of equations in problems with boundary conditions.

Result. The exact values of critical forces in non-classical problems of the stability of compressed rods are determined, which is proved by the obtained curve from the monitor screen.

Conclusion. The main points of the theory of calculation in the study of the stability of multi-span rods are outlined. To find the critical forces of a multi-span rod on elastic supports, a simple algorithm for solving problems is given.

Objective. The aim of the study is to study the operation of beams under the simultaneous influence of combined actions: moments at the ends, kinematic harmonic displacements of both supports, a distributed load with different amplitudes, frequencies, phases, and the presence of viscous friction.

Method. The study is based on solving a boundary value problem and modeling.

Result. Investigated the forced transverse vibrations of beams with constant cross-subject to damping. Considered non-periodic, periodic and harmonic oscillations of the beams from vector perturbations. Examples of solutions for various conditions bearings beams.

Conclusion. The author's development can be adapted to vibrations of bars of variable cross section, to vibrations of continuous-discrete bars. The resulting transfer functions make it possible to calculate building elements in the form of rods for random processes, taking into account their correlation.

Objective. International practices demonstrate advantages of expanded clay in road construction in difficult climatic and geotechnical conditions. The clay is present in abundance in Siberia and in the Far North which is suitable for the production of expanded clay gravel. At the same time there is a strong deficit of the road construction materials in these regions. The aim of the study is to develop a new approach for providing claydite for the construction of northern roads.

Method. The modernization of the equipment means that each unit included in the complex can be transported on existing trucks, and then mounted in a line for the production of expanded clay in the field.

Result. A mobile complex for the production of expanded clay gravel, serial and modernized equipment for the production of expanded clay has been developed.

Conclusion. Large units - drying drums and rotary kilns for drying and firing pellets should be divided into prefabricated sections, for example, with a diameter of 2 m and a length of 5-7 m. For the electric drive of the units, a diesel generator of sufficient power must be included in the equipment set. The productivity of one complex is from 15 thousand cubic meters of expanded clay per year and above.

Objective. The task was set to analyze the current situation in relation to the quantitative and qualitative state of a comfortable urban environment at night, namely the lighting of the pedestrian zone along the Kubanskaya Street in Astrakhan.

Method. The study is based on analytical and design methods.

Result. During the calculations, areas were identified that did not meet the standards for lighting the urban environment at night. To achieve this goal, a project has been developed to organize comfortable and safe lighting for areas located along. A description of the methods for calculating lighting fixtures by functional zones is given. The data obtained from the calculations are summarized in a table and represent a project solution for organizing comfortable lighting.

Conclusion. The developed set of practical measures justifies the need to introduce additional lighting devices along.

Objective. The aim of the study is to develop a repair and restoration composition of materials and a technology for restoring a tower-type object.

Method. The experimental method of destructive and non-destructive quality control of building materials was used in the work; comprehensive instrumental technical inspection of buildings and structures; visual inspection of buildings and structures.

Result. A situational review of the object of cultural heritage was carried out. Physical and mechanical tests were carried out in order to select the restoration composition for masonry walls of tower buildings. The results of a visual inspection are presented, on the basis of which a comprehensive assessment of the state of a cultural heritage object is given for carrying out repair, restoration and restoration work at this object. The conclusion of a comprehensive instrumental technical survey on the condition of the object was drawn up. The composition of materials for the repair, restoration and restoration of tower-type cultural heritage sites has been determined.

Conclusion. As a result of the technical survey, it was found that the general condition of the facility is emergency. A repair and restoration composition has been developed that, in its properties, is as close as possible to the original, more efficient and contributes to improving the quality of work and the durability of a cultural heritage object.

Objective. This article discusses flat large-span structures, provides features of their work, as well as design examples. Formulas are given for determining the general dimensions of these structures.

Method. Features of work and design, as well as calculation formulas are given. Shipping marks, types of sections and junctions of elements are given. A technique is described that allows to reduce span bending moments. Examples of rational design of beam trusses are given.

Result. The given structural diagrams, as well as the analysis of their work, allow us to design long-span flat structures that are reliable, lightweight, technologically advanced in terms of manufacturing, transportation and installation. The types of sections and junctions described in the article are used in the practice of design and construction.

Conclusion. The article discusses rational design solutions that allow reducing the own weight of flat large-span structures due to the optimal choice of their design and design scheme.