Bryansk State Technical University

The paper presents a metal research analysis of crankshaft working surfaces, which is a critical element of the internal combustion engine. The study is aimed at identifying microstructural features, defects and patterns of surface wear under operational loads. The relevance of the study is due to the need to predict the service life of shafts and prevent emergency failures due to fatigue failure and intensive wear. The study objective is to find out formation patterns of the structure and properties of surface layers in areas of maximum contact and bending loads (main and rod journals, fillets, mounting surfaces), as well as to identify mechanisms of material degradation under operating conditions. The key mechanisms of material degradation are identified: fatigue microcracks, adhesive and abrasive wear, and local zones of plastic deformation. To achieve this objective, a set of methods was used: determination of the material chemical composition, determination of hardness on journal fragments, determination of the microstructure of samples. Criteria for estimating the residual life of the shaft based on metallographic features are proposed. The results of the study make it possible to optimize the operation and repair of crankshafts, increasing the reliability and durability of engines. The results can also be used in the design, manufacture and repair of crankshafts to improve engine reliability.

This article provides an overview of the modern market of partner selection services in online games, analyzes the products offered on the market using ten Nielsen heuristics. As the part of the service design, scenarios for the use of the proposed service have been proposed, as well as diagrams of the activities and use cases of the partner selection service have been developed, describing the functionality of the service and its general flows. As a mathematical model that implements selection functionality, a hierarchy analysis method is proposed, which suggests the main criteria for potential partners and an assessment of their effectiveness. Within the framework of this method, six criteria for evaluating potential partners are considered, on the basis of which a global priority is derived. The proposed model makes it possible to select a suitable partner for the game based on calculated global priorities.

There are known DC and AC electric drives with excitation control, containing negative feedback circuits for speed and flow derivative. In such drives, with an increase in the number of elements included in them, the efficiency always decreases proportionally to the number of links included in them. . Further, the power consumption will also decrease as the number of links in the chain with other consumers increases. The device described below belongs to the field of electrical engineering, namely to electric drives with speed feedback. The drive uses a parallel oscillating circuit in which the current resonates. When the current resonates in a parallel oscillatory circuit, the total current in the branched section of the circuit where the armature of the DCm motor is located can be many times higher than the active current in the non-branched section of the circuit where the armature of the generator is located. In this case, the power generated by the full current will be converted into useful work in the DCm armature, since in the constant magnetic field of the DCm armature disk at full current (active and reactive) an Ampere force will occur, causing the disc to rotate.

There are known DC and AC electric drives with excitation control, containing negative feedback circuits for speed and flow derivative. In such drives, with an increase in the number of elements included in them, the efficiency always decreases proportionally to the number of links included in them. That is, if the power supplied to the drive motor is Pe = I × U, , then the power on the drive motor shaft will be equal to: P dr = Pe × Kdr , where Kdr - efficiency of the drive motor. The generator will supply the following power: Pg = Pe × Kdr × Kg, where Kg - generator efficiency. Further, the consumed power will also decrease as the number of links included in the chain with other consumers increases. The device described below is related to electric drives with speed feedback. The drive uses a parallel oscillatory circuit in which current resonance is achieved. This parallel oscillatory circuit has a built-in brushless anchor of a direct current motor DCm, which is powered by a brushless anchor of an alternating current generator G, made according to the synchronous generator scheme. The anchor of the generator G and the motor DCm are on the same shaft, forming a single system that is driven by the drive motor DM.

This review is focused on critical analyses of the textbook titled “Fundamentals of Publication Activity”, authored collectively by scholars from Empress Catherine the Great Saint Petersburg Mining University. The subject matter addressed in this textbook represents a nascent field within the Russian education. Current educational materials typically lack systematic coverage of scientific publication processes. One notable advantage of this publication lies in its systemic approach to exploring the theme. Among the co-authors are journal editors, scientometricians, and educators. They effectively address critical issues arising throughout the manuscript preparation process, its submission procedures, and subsequent promotion in the information space. Additionally, the authors provide detailed insights into different types of scholarly documents, outline key stages involved in preparing manuscripts, offer recommendations regarding interactions between authors and editorial boards/reviewers, discuss criteria for publication ethics, describe how published works function within diverse information systems, and present mechanisms for evaluating publications. This textbook serves as a valuable resource for young researchers, graduate students, and professionals engaged in teaching undergraduate students the fundamentals of publication activity.

The article examines an approach to documenting the quality management system (QMS) of a higher education institution (HEI), following the principles outlined in ENQA and ISO 9000 series based on integrating into the considered model of the standards GOST R ISO 10013-2024 and GOST R 7.0.97-2016. The work analyses challenges and associated discrepancies in forming registers and forms of QMS documentation at HEIs caused by two factors. Firstly, the lack of specificity regarding development and control of documented information in the current family of international ISO 9000 standards (version 2015); secondly, the release only in December 2025 of the anticipated new version of ISO 9000:2025 standards, which raises hopes among the scientific community for resolving these issues. The authors justify the relevance of applying specific approaches, particularly for identifying the register of documented QMS information using GOST R ISO 10013-2024 and standardizing document formats according to GOST R 7.0.97-2016. The work discusses testing the proposed methodology by developing and formatting the form of this key QMS document of the higher school, which is the policy statement on quality. Finally, one substantiates the prospective value of adopting an approach to enhancing documented information based on integrating the standards GOST R ISO 10013-2024 and GOST R 7.0.97-2016 into the quality model. This allows for improving the quality of the higher education institution’s QMS documentation and reducing uncertainty in verifying its conformity in certification authorities.

The issues of obtaining composite finishing materials from soft-leaf wood with a texture imitating the texture of oak are considered. It has been revealed that our country is significantly lagging behind the profitability level of the timber industry and the profitability level of advanced industrialized countries. A condition has been formed for increasing the profitability of the timber industry by increasing the volume of processing soft hardwood and creating products with improved operational properties from it. The methods of manufacturing finishing composite materials from soft-leaved wood are analyzed, and it is proposed to use alternating sheets of peeled veneer of different breeds and colors, which ensures the formation of a pronounced texture. It is shown that the proposed import-substitution method provides the production of finishing materials from soft hardwood, imitating the texture of valuable hardwood wood. It is shown that the proposed import-substituting method provides the manufacture of finishing materials from soft hardwood, imitating the texture of valuable hardwood wood. It is proved that, unlike foreign fine-line technology, veneer dyeing is not required, and this simplifies the technological process and improves the environment. It is shown that soft hardwood is used to a limited extent due to low strength parameters, which are determined by density. The effect of the bonding time; the thickness of the package and the temperature of the press plates on the density of samples according to the Box plan (B3) was studied. Statistical processing was carried out, graphical dependencies were constructed using computer programs PlanExp B-D13, Excel and SigmaPlot. A regression equation has been obtained that adequately describes the dependence of the density of decorative strips on the bonding conditions: the duration of pressing, the thickness of the veneer package, and the temperature of the press plates. The possibility of obtaining decorative slats from soft hardwood of increased density has been established. It was revealed that the pressing time and the thickness of the veneer package have the greatest effect on the target function, and the maximum density value of 830 kg/m3 is reached with a pressing duration of 8 minutes and a veneer package thickness of 13.5 mm. Considering that the cost of raw materials in the cost structure is about 30%, the use of this method will ensure a reduction in production costs in the manufacture of products. The method of manufacturing composite finishing materials proposed by the authors is economically advantageous: the cost of 1 m3 of oak raw materials is 70,000 rubles, the cost of 1 m3 of birch raw materials is 5,000 rubles.

The basics of the design of rotary kilns, widely used in the processing and preparation of various raw materials, are described. It is shown that the weak point of the rotary kilns design is the support rollers, which carry the entire load of the kiln and are initially made of less durable steel than a bandage being in contact with them. In fact, the design itself provides for the possibility of periodic replacement of the «miscellaneous part», which is a support roller. However, for an operator, any downtime of equipment leads to economic losses. Therefore, the goal has been formulated: to increase the durability of the support rollers avoiding a significant change in the kiln design. For this purpose, initially, from the point of view of contact mechanics, the basics of the interaction of the surfaces of the support roller and the bandage of a rotary kiln have been studied. Calculation models for various contact options of these parts have been given. The force model of contact between the surfaces of the support roller and the bandage has been studied. The maximum normal and tangential stresses in the contact zone, at its boundary and beyond have been determined. At the same time, complex processes occur in the contact area of the roller and the bandage surfaces, in particular, micro-slipping and sliding, due to the difference in the diameters of the rotating bodies and the difference in the level of their mechanical properties. Micro-slip is one of the sources of fretting wear. However, the most significant wear occurs as a result of mechanical interaction and changes in the structure of the surface layer with the gradual accumulation of various kinds of defects in the crystalline structure caused by plastic deformation of the surface layer of the contacting parts. It is shown that not only the mechanical and operational properties of the material for their construction, but also the displacement of the contact spot during kiln operation have a significant effect on the wear process of the support rollers. The displacement can be angular or linear, and in real conditions it is most often combined, it is caused by the thermal expansion / compression of the metal structure and the operating conditions of the rotary kiln.

The influence of strain wave hardening on the corrosion resistance is investigated. Specifically, the influence of the following factors on the corrosion resistance is analyzed: the grain size of the metal, the angle of grain rotation, and the size and hardening depth of the surface layer. To increase the corrosion resistance of a part by means of strain wave hardening, more than 30% hardening must be ensured.