Gas-shielded arc welding today occupies a leading position among the methods for producing permanent joints in industrial conditions. The emergence of new materials with complex alloying and hardening systems makes carbon dioxide, traditionally used as a protective medium, inefficient for use. One of the effective ways to solve these problems is to change the composition of the protective gas atmosphere, which allows you to significantly change the physical and metallurgical processes of melting the electrode wire and the forming the weld. At the same time, the transition to the use of protective gas mixtures based on argon is usually carried out without understanding the essence of the technology and possible problems associated with the specifics of penetration of the base metal, which can cause a number of serious problems. The present paper describes important regularities between technological characteristics of  arc welding  in a shielding gas mixture Ar + CO₂ and welding mode parameters under conditions of deviation of their values from the most effective ones in order to ensure the stability of the processes of electrode metal transfer and the formation of the deposited weld metal bead. On the basis of experimental data, the most probable causes of the appearance of a dangerous and difficult-to-detect defect in the formation of a welded seam in the form of non-fusion between individual beads of the deposited metal and along the fusion line with the base metal of the welded parts have been established. The defect is common and can cause unpredictable failure of the welded joint without visible plastic deformation. Empirical dependences for determining values of the main parameters of the welding mode are proposed as well. Important regularities have been established that make it possible to increase the efficiency of arc welding technology in the environment of protective gas mixtures in the conditions of domestic production.

The paper presents the results of studies of the influence of the components of a complex polyfunctional additive on the protective ability of concrete in relation to steel reinforcement of reinforced concrete building structures. In accordance with modern trends in the use of chemical additives in concrete with the aim of a complex effect both on the processes of hardening and the formation of its structure, and on the final physical, mechanical and operational properties of concrete, the additive in question consists of a number of components. It consists of a plasticizing component, accelerating hardening and compacting the structure of hardening concrete, as well as amorphous ultrafine microsilica. The presence of the latter is accompanied by a reaction with calcium hydroxide and its transfer to a bound state in hardening concrete, which creates prerequisites for a decrease in alkalinity (pH factor) in its volume and, accordingly, can create a risk of corrosion of steel reinforcement of reinforced concrete structures. Taking into account this circumstance, studies have been carried out in order to establish the degree of influence of the amorphous ultrafine microsilica present in the composition of the additive on the properties of concrete, including an assessment of its protective properties in relation to steel reinforcement, as well as a change in strength over time (in this paper up to the "age" of concrete in three years from the moment of manufacture of samples of compositions without chemical additives and with the introduction of a complex polyfunctional additive). As a result, an increase in the density, strength of concrete and its operational properties, including the protective ability in relation to steel reinforcement, due to the complex effect of the additive components, has been revealed, including a decrease in the initial water content and an increase in the density of the cement stone and transition zones of its contact with the surface of the aggregate grains in concrete.

The paper presents calculations of vibrations of the soil mass when a horizontal inertial barrier in the form of a rectangular concrete slab buried in the ground is placed on the propagation path of vibrations. The damping effect of a surface wave upon its contact with an inertial plate is associated with its reflection, refraction and partial absorption. Theoretical studies have been carried out using the finite element method. The ground medium has been considered as an elastic inertial array bounded by non-reflecting boundaries. Various variants of the geometry of the inertial plate and its spatial arrangement on the surface of the soil medium between the vibration source and the considered point behind the barrier are modeled. The effectiveness of each variant of vibration isolation has been quantified by the value showing how many times the speed of vertical oscillations of the ground behind the barrier decreases compared to the free propagation of surface waves. It is shown that an intensive  decrease in vertical displacements occurs starting from the side face of the inertial plate. Here, the amplitude of vertical oscillations decreases by 9,8 times for a concrete slab 15 m long, and by 4,2 times for a 3-meter slab. At a distance of 22 m from the point of application of the dynamic load, the amplitudes decrease by factors of 5.48 and 2.95, respectively, for slabs  of 15 and 3 m width. This method of reducing vibro-dynamic effects has a simple design and can be used in cramped conditions of urban development to protect existing and planned buildings and structures.

During operation, the asphalt concrete pavement is subjected to various destructive influences associated with external natural, climatic and operational factors, which can cause its premature failure. Over the past 10 years, there has been a significant increase in the fleet of vehicles in the Republic of Belarus, and, consequently, the intensity of traffic on the roads with a proportional increase in wear and destruction of their coatings. This situation is exacerbated by extended turnaround times for a number of transport facilities. The need to protect asphalt concrete pavements from the effects of external aggressive environments determines the search for new technological solutions in the creation of necessary materials, the range of which is quite wide. Existing protective compositions differ both in purpose and in the content of components. Modern research in the field of protective treatments for asphalt concrete pavements of highways, as well as technological processes used in road organizations, can effectively extend their service life. At the same time, the current research work, proven technological processes, as well as the well-known works of scientists in this field offer an insufficient number of sound technical and design solutions that allow for direct preventive protection of pavements and use for this purpose available, including secondary, materials. For more effective protection of pavements from the complex effects of water and traffic loads in the autumn-winter and spring-winter period, it is necessary to develop and implement alternative technologies, one of which is the treatment of road surfaces with the Protect-01 hydrophobic prophylactic composition. The paper presents the results of studies of the effect of treatment with the Protect-01 hydrophobic preventive composition on water saturation (decrease by 30–40 %,) frost resistance (increase by 10–12 %) and residual porosity (decrease by 12–25 %) of cores from asphalt concrete mixtures, as well as its optimal formulations.

An assessment of the state of the region’s core road network is necessary to determine the level of transport accessibility and mobility of the population in a particular area. The core road network is the roads along which goods and passengers are transported by personal, public and commercial vehicles. Currently, the assessment of the road network is carried out using geographical, economic, mathematical and general technical parameters. The disadvantage of these assessment methods is the lack of a comprehensive analysis of both the level of development of the core road network and the transport accessibility of the region. The authors propose a method of additive multicriteria modeling using weight coefficients. The parameters have been considered and weight coefficients have been selected, which significantly affect the reliability of determining the sufficiency of the road network. The analysis of individual criteria for the quality of the transport network has been carried out. Based on the use of statistical parameters, the values of the weight coefficients of the additive model have been determined. The proposed method using an additive multi-criteria model is reliable and universal, which makes it possible to comprehensively evaluate the core network of roads in conjunction with other means of communication (railway, air and water transport). In addition, the method can become part of the methodology for substantiating the inclusion of the designed roads in core network of the region.

Gas distribution system is a production complex, which is part of the gas supply system and consists of organizational and economically interconnected facilities designed to organize the supply of gas directly to consumers. On the national basis of the gas distribution system is formed by about 67.0 thousand km of external distribution gas pipelines, 28.0 thousand km  of which are underground steel pipelines. As potentially hazardous objects, steel underground distribution pipelines are subject to higher requirements for corrosion protection. As a rule, they are provided with complex anticorrosion protection, an obligatory component of which is insulation coatings. Taking into account the above mentioned, the definition of general indicators characterizing condition of insulation, the degree of its wear is an actual task. To solve it, for the first time, we have analyzed an array of long-term statistical data on defects of protective coatings of distribution gas pipelines, detected by instrumental method. The values of specific defect density Dd and damageability Ad have been determined for all types of applied protective coatings. The best values have been found for insulation on the basis of heat-shrinkable tapes. The characteristic damage of  the protective coating on the basis of bituminous mastics (microcracks), which can be used as an indicator of aging of this type of insulation, has been determined. It has been shown that defect formation in the insulation coatings of gas pipelines up to the present time is, as a rule, a low-intensive process, which has been confirmed, among other things, for  gas pipelines operated for a long time. The obtained results were included into the justification of abolition of the previously used 40-year normative service life of steel gas pipelines in the new edition of the Rules of Technical Safety in the Field of Gas Supply of the Republic of Belarus.

In the existing microprocessor-based directional current protection lines from phase-to-phase short circuits, digital power direction elements are used, which, as a rule, are switched on at full currents and voltage according to the so-called 90-degree pattern. With this switching scheme, a “dead” zone appears only in case of three-phase short circuits close to the protection installation site, which make up a small fraction of all possible types of such damage. Nevertheless, its presence is a significant drawback of the power direction organs. The principles of organ execution based on digital operations with orthogonal components of input voltages and currents have been considered. The result of the functioning of the power direction body is reduced to the development of an information sign equal to: one – with the direct direction of power; minus one – when it is in the opposite direction.  To eliminate the “dead” zone, the work of the organ is organized using the voltage “memory”.  In order to obtain the required duration of the “memory”, frequency compensation is implemented. The study of the effectiveness of the decisions made, as well as the behavior of the power direction control in normal and emergency modes, has been carried out by the method of a computational experiment. In the MATLAB-Simulink-SimPowerSystems dynamic simulation system, models of the electrical system and a digital power direction control have been developed. The results of the research have shown that the joint use of the existing and proposed principles for the implementation of a digital power direction control ensures an increase in its technical perfection and eliminates the “dead” zone while maintaining its stable operation for an arbitrarily long period of time.

. The paper presents the results of experimental studies of the hydrodynamics of the coolant in the core of the PWR reactor with fuel assemblies “TVS-Kvadrat” of various designs. Experimental studies of hydrodynamics consisted in studying the velocity fields and the process of cross-flow of coolant between adjacent fuel assemblies “TVS-Kvadrat” of various designs in homogeneous and mixed cores on large-scale experimental models, including fragments of two adjacent fuel assemblies “TVS-Kvadrat” and a gap between them. The test models differ in the number of installed grids, this is due to the fact that in a homogeneous core the hydraulic load along the height of the fuel assemblies is identical, and in a mixed core the hydraulic load is uneven due to the different number of installed grids. The hydrodynamics of the coolant has been studied on an aerodynamic open-loop based on the theory of hydrodynamic similarity, using individually calibrated pneumometric sensors. Based on the data obtained, the fields of local axial and transverse velocities in various sections along the length of the studied section of the test models have been constructed. The fields of local dimensionless transverse and axial flow velocities in the fuel bundles and the gap between the fuel assemblies “TVS-Kvadrat” of the PWR reactor core have been studied. Peculiarities of the process of transverse flow between adjacent “TVS-Kvadrat” of a homogeneous and the mixed core of the PWR reactor have been revealed. The results of experimental studies have been transferred to the developer of “TVS-Kvadrat”, that is  JSC “Experimental Design Bureau of Mechanical Engineering named after I. I. Afrikantov”,  for further use in justifying the design and operating modes of a nuclear power plant.

The paper describes further development of model studies with the purpose to draw analogies of the occurrence  of possible inhomogeneities and defects of the fractal type on the surface of various objects under the action of laser radiation for different conditions and schemes of a laser simulation experiment in comparison with real processes in the chambers of thermal machines due to the contacts of the working substances with their surface. The subject of this consideration is related to the fact that in laser schemes one can relatively easily and in a controlled manner to study their topology in various modifications (in the range of 0D–3D structures formed on surfaces of various geometric shapes of the fractal type). This provides great opportunities for studying various frequently occurring undesirable random defects and inhomogeneities of  complex configuration with the development of unexpected processes in the dynamic modes of operation of various types of power units in their actual operation. This is determined by geometric analysis within the framework of the correspondding non-linear models with different  non-linear fractal images. In this aspect, we have used two models to consider the development of emerging fractal fractured structures: first, diffusion propagation/growth of cracks of different geometry with a set of local segments and fragments in different directions; secondly, with diffusely limited aggregation of their distribution (Diffusion-Limited Aggregation – DLA) using the formalism of cellular automata in percolation approximation for different algorithms for the formation of fractal structures. We present only the final results of calculations without details of their procedure, which is sufficient for a visual and qualitative determination of the process of growth of fracturing and defects. In this case, the final goal of consideration is to study the emergence of possible and controllable local areas / collectors, starting from surface structures, and their association with real objects on the surface of chambers with a working substance in power systems. The possible practical significance of such modeling and analysis is discussed to forecast their working conditions.

Рurpose of the work is to develop the theory of corporate management of Chinese transnational corporations (TNC) by identifying and substantive characteristics of the factors influencing these relations. The methodological main of research are systemic and comparative analysis, the method of conceptualization of scientific ideas, the method of qualitative and quantitative assessment, the subjective approach. The following are identified as the main factors determining the directions, tools and forms of development of corporate management in China: strengthening economic interdependence within macroregions, including through transnational corporations, with the growth of economic and geopolitical confrontation between macro-regions; high rates of economic growth of the country, requiring the expansion of transnational forms of doing business in order to stimulate exports and provide access to the necessary import resources; expansion of the private sector while maintaining state control over assets in key industries and the development of the national stock market; the ongoing credit and financial policy of the state, which provides Chinese TNCs with privileged access to financial resources; reconfiguration of the global technological space in favor of China, which contributes to the development of Chinese TNCs in the ICT (information and communication technologies) sector and the improvement of corporate management on a new technological basis; the leading role of the Communist Party in the political life of the country, which allows Chinese TNCs to use political capital to increase competitiveness; national cultural and worldview features that contribute to the formation of a specific culture of corporate management (guangxi), characterized by a high level of social capital and a focus primarily on collective interests. The novelty of the results obtained lies in the disclosure of a variety of factors and the mechanism of their influence on the corporate management of Chinese TNCs, a high degree of interdependence of internal and external factors, as well as in the study of economic, political and cultural factors not in isolation, but in the unity of their influence on the object of study, which allows significantly improve the quality of economic analysis of the development of corporate management in China.