bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the efficiency of aerodynamic dampers based on preliminary numerical modeling
Authors: Churin P , Pomelov V
Published: December 2021

The article is devoted to the issues of ensuring the stability of large-span bridge structures by means of their aerodynamic damping. Aerodynamic damping allows you to change the nature of the wind flow around structures or their individual elements, which can significantly reduce the loads that cause the occurrence of various aeroelastic phenomena. Aerodynamic damping devices (fairings, deflectors) are based on the phenomenon of changes in the circulation of the wind flow around the structure, the purpose of their use, as a rule, is to disrupt regular vortex formation. The main problem when using these devices is the lack of recommendations for their selection and the need for costly experimental studies to assess their effectiveness for each specific bridge. One of the ways to reduce the time and cost of research is preliminary numerical modeling in specialized software systems. Within the framework of this study, the most common types of aerodynamic dampers have been analyzed, and typical designs of large-span beam bridges have been selected. For the selected structures, a preliminary numerical simulation was carried out in a two-dimensional formulation. Based on the results obtained, the most effective designs of deflectors and fairings were determined.
Control of gas transmission system in non-stationary consumption modes
Authors: Marchenko S , Ivashchuk O
Published: December 2021

The article deals with the issues of modeling and control of the gas transmission system in non-stationary consumption modes. The topology of the gas transmission network is parameterized in the form of a digraph, with weighted vertices representing the vertices-the drains of consumers, the vertices-the sources of suppliers, transit vertices (compressor or gas distribution stations) and arcs indicating the main parameters that affect the throughput of the system. A hierarchical model of gas transportation system management is proposed, where the upper level is the flow diagram of gas transport, and the lower level simulates the physical processes of gas flow in the pipe section. A procedure for dynamic control in non-stationary consumption modes is developed, which is represented as a sequence of transitions between stationary flow schemes according to the criterion of minimizing their mismatch at neighboring time intervals corresponding to the intervals of constancy of consumption requests, which further reduces the energy costs of changing the flow scheme. The practical value of the research results lies in the possibility of their use while dispatching control.
Using the neural network in clinical systems
Authors: Gusynina Yu S , Shornikova T A
Published: December 2021

The article examines the identification of human bone fractures using convoluted neural networks. The method of recognition of photographs of patients is intended for automated systems of identification and video recording of images. Convolutional neural networks have a number of advantages, such as invariability when reducing or increasing image size, immunity to photo movements and deviations, changes in image perspective, and many other image errors. In addition, convolutional neural networks allow you to combine neurons at a local level in two dimensions, connect photographic elements in any place, and also reduce the total number of weights. The work describes a multi-layer convolutional network. The layers of which it consists are divided into two types: convolutional and sub-selective. Of interest is the use of the principle of weighting in the work. This principle allows you to reduce the number of characteristics of the neural network that can be trained. Network training is based on the rule of minimizing empirical error. This rule is based on the algorithm of inverse error propagation. This algorithm provides an instant calculation of the gradient of a complex function of several variables in case the function itself is predefined. Neural network training is based on probabilistic method. This method leads to more optimal results due to interference in the restructuring of network weights. The work confirms the axiomatics of the applied neural network, its architecture and its learning algorithm.
Mathematical model of heating system before the melting of the metal suspension upper half in the manufacture of turbine blades GTE
Authors: Vdovin R
Published: December 2021

The article presents the developed mathematical model of heating system before the upper half of the metal suspension melting during the technological process of manufacturing the turbine blades in a discrete-continuous casting plant. The relevance of this research is connected with the lack of reliable mathematical model that can predict the distribution of temperature fields and heat flows inside the plant, which have a direct impact on the quality of formed macro - and microstructure in the castings of turbine blades. The currently existing methods of indirect indicators’ estimation carry significant errors in the selection of optimal technological modes of the blade casting process. The developed model makes it possible to predict more accurate the distribution of temperature fields and heat fluxes in the corresponding zones of the casting plant. Thanks to this, it is possible to predict with maximum accuracy the production of blades with a given internal structure, as well as to estimate the amount of volumetric shrinkage and deformation of the casting. The developed mathematical model in production conditions will make it possible to predict casting defects in the form of captivity and failure, reduce labor capacity and increase the productivity of the blade casting process.
Approach to setting the mode parameters in combined electro-erosive - electrochemical processing during piercing the deep holes of small diameter
Authors: Vasilevskaya S , Nikitin Yu
Published: December 2021

The article considers the problem of forming the deep holes of small diameter by using the combined electro-erosive and electrochemical machining based on the electrochemical and electro-erosive processes. The approach to setting the mode parameters during piercing the deep holes with a diameter of less than 1 mm is suggested. The approach takes into consideration the influence of hydrodynamic losses in the inter-electrode gap on the limitation of the mode parameters of the electrochemical and electro-erosive components in the combined processing. It also takes into account the interrelation between the magnitude of the inter-electrode gap and the linear velocities of the removal of the processed material in each of the components during the combined processing. The validity of the approach to setting the mode parameters in the combined electro-erosive -electrochemical processing during piercing the deep holes with a diameter from 0.3 mm to 1 mm in the range of the inter-electrode gap from 0.025 mm to 1 mm is experimentally confirmed.
Ion beam technology for the resource enhancement of responsible parts of a high speed friction unit
Authors: Krivina L , Tsareva I , Tarasenko Yu
Published: December 2021

The needles from carbon steel “U10”, a details of high speed couple of friction “needle-thrust plate” of the gas centrifuge is investigated, in the initial, post-operational state and after irradiation by C+ ions different doses on the pulse-frequency “Raduga” accelerator. The purpose of this study is to increase the operability and service life of the responsible friction unit of the gas centrifuge. This purpose is achieved by mod-ification of the working sliding surface of the needle (which is a responsible part of the high-speed friction pair “needle-thrust plate”) by the pulse-frequency implantation with carbon ions. The dose of implantation (1018 cm−2 of C+ ions), was established, at which an optimal combination of mechanical and tribological properties of the working surface is achieved, which provides wear resistance increase during the operation of the friction pair. This method of surface treatment is recommended to use in case of operation of couple of friction “needle-thrust plate” for the purpose of increase in working capacity and a resource of operation of high speed couple of friction of the gas centrifuge.
On the probability of formation of intermetallic compounds in dissimilar welded joints obtained by friction stir welding
Authors: Rzaev R , Chularis A , Derzhavin I , Bich G , Merkulov D
Published: December 2021

The article describes the mechanisms and causes of the occurrence of intermetallic phases during friction stir welding of dissimilar joints. The nucleation and growth of intermetallic phases for a pair of dissimilar metals to be welded under comparatively favorable time and temperature conditions of the FSW is facilitated by the atomic-vacancy environment, which is responsible for the continuous atomic-structural bond and mass transfer of accumulated atoms in local regions of the welded joint with an equiaxial grain lamella-shear structure of the welded core. compounds with a concentration close to critical, combined with others in a superplastic state. In the process of forming a welded joint under the influence of a moving and rotating welding tool, the lamellae are subjected to bending and torsional stresses with simultaneous tension, causing them to generate point defects and especially a large number of various types of dislocations, triggering the formation of edge dislocations in the lamellae, which are lined up in the process into dislocation walls, dividing lamella grains into separate fragmentary subgrain boundaries, along which the processes of fragmentation and dispersion develop. This phenomenon is explained by the fact that the processes of fragmentation and dispersion of IMP lead to the composition of the nugget of the welded joint by fragments, often nano-sized fragments of various configurations, which act as hardeners of the weld nugget matrix.
Selection of rational electrochemical methods for controlling the efficiency of machining of corrosion-resistant steel
Authors: Astsaturov Yu , Solovyov S , Zhigulsky V
Published: December 2021

The article discusses methods of controlling the processes of mechanical processing based on electrochemical effects. The corresponding anodic polarization curves of 1X18H9T steel obtained in electrolyte solutions without and with stirring are presented. The article discusses methods of machining processes control based on electrochemical effects. Lubricating and cooling technological media (LCTM) used in machining are in most cases electrolytes, therefore, electrochemical processes and phenomena actively occur during contact dynamic machining. It is possible to control the processes of machining by acting on the system elements of the tool - LCTM- part, in particular by activating the LCTM and reducing the strength characteristics of the processed steel in the cutting zone. A reserve for increasing the efficiency of mechanical processing can be the composition selection of the applied LCTM, combined with the simultaneous electrochemical polarization of the treated surface of friction pair parts. It was found that when cutting, the efficiency of machining and the chip shapes are changed, which is explained by the influence of the current density on the strength of the processed steel. In the conditions of machining, complex dynamic processes occur due to the rotation of the work piece and/or tool, so it is necessary to take into account the hydrodynamic phenomena and processes that arise in this case. Electrode potentials are considered to be the most important characteristic of the metal cutting process. The potential of the system can regulate such processes and indicators as wear and surface micro hardness. Anodic polarization curves of the steel 1X18H9T obtained in various electrolyte solutions without stirring and with stirring on a rotating disk electrode are given. The study allowed determining the factors affecting the processes occurring in the cutting zone and to identify rational current densities due to simulating the conditions of real technological processes of the combined steel processing. The increase in the processing intensity of the steel 1X18H9T with the cutting zone polarization is associated with the action of factors activating the selective anodic dissolution of the processed alloy.
Chip formation processes based on orthogonal processing of polymer composite materials
Authors: Volkovsky A , Makarov V
Published: December 2021

This paper presents the results of the study of processes occurring in the cutting zone during the processing of polymer composite materials. The research included determining the effects of orthogonal cutting conditions, such as the cutting depth t and cutting rate v, on the tangential component Pz
of the cutting force, the length lc
of chips, as well as the vibration acceleration W, to clarify the results previously submitted to the scientific community and obtain new data. The study included 12 experiments for different cutting conditions with the cutting depth t varying in the range of 0.1—0.4 mm and the cutting rate — in the range of 6.7—30.2 m/min. The experimental results allowed to determine a range of cutting rates that lead to a low level of elastic deformations of reinforcing fibers. Based on the dynamics of increasing cutting forces in various cutting conditions, tool cutting edge wear, type and length of chips, as well as the vibration acceleration dynamics, we have found that reinforcing composite material fibers accumulate on the tool cutting edge, while elastic fracture of these fibers causes defect formation on the processed surface. The analysis allows giving recommendations on the need for research in the field of abrasive machining with rigid grinding wheels due to the highest hardness of the cutting tool surface, increased machining speed and the possibility of self-sharpening during tool wear.
Polyamide self-lubricating composites filled with thermolysis products of lignin: composition, structure, properties
Authors: Serbinovskiy M , Popova O , Finochenko T , Serbinovskaya A
Published: December 2021

Compositions of antifriction composites with a polyamide matrix filled with carbon additives obtained by modifying hydrolytic lignin (graphite from lignin, graphite bisulfate from lignin, thermally expanded graphite from lignin) have been developed. Powders of carbon materials were impregnated with cylinder oil before being added to the polyamide matrix. The tribotechnical characteristics of filled polyamide composites, their microstructure and water absorption kinetics have been investigated. It was found that the lowest values of the friction factor are observed in composites filled with thermally expanded graphite from lignin. The friction factor for such composites is 1.5-2 times less than the indicators obtained for currently used graphites. Thus, at specific loads of 0.67 and 2.33 MPa, the friction factor was 0.065 and 0.064, respectively. The investigated antifriction composites have low water absorption compared to pure polyamide. The maximum water absorption (2.2%) in the series of the studied composites had the samples filled with graphite from lignin with an oil content of 9%. According to the data of microstructural analysis, the structure of composites with additives of carbon materials from lignin is homogeneous. The components, including the oil plasticizer, are evenly distributed, the bulk of the oil is localized in the interlayer spaces. The elemental composition of the composites indicates the high chemical purity of the composites. Antifriction composites with the proposed additives are recommended for use in friction units operating in an aqueous mediumor an environment with high humidity.
Electrochemical method of obtaining copper (II) oxide powders in alkaline electrolyte
Authors: Demyan V , Mikhailenko V , Zhukova I
Published: December 2021

Within the framework of these studies, an electrochemical method for the synthesis of highly dispersed powders of copper compounds in aqueous solutions of alkalis is presented. The factors influencing the rate of production of nanoscale copper (II) oxide particles are determined. It is shown that during the anodic oxidation of copper by direct current, the speed of highly dispersed powders formation depends on current density, the nature of alkali cation, and the concentration of electrolyte solution. The mass loss of copper electrodes in NaOH solution is higher than in solutions of potassium hydroxide and lithium hydroxide by 10% and 12%, respectively. This experiment suggests that the studied alkalis act similarly on the anodic behavior of copper and the nature of cation does not significantly affect the speed of anodes destruction. The change in the concentration of alkali solution practically does not affect the mass loss of copper electrodes. The speed of copper oxidation remains almost constant over time, but noticeable weight loss and, accordingly, the speed of copper dissolution is achieved within 15 minutes. The speed of copper oxidation does not depend on current density. It is determined by the amount of electricity that has passed. The current density of 1 A/cm2 can be considered optimal.
Functional composite electrochemical coating Ni-Co-Al2O3 -an alternative to chromium plating
Authors: Ovchinnikova K , Zhukova I , Degtyar L
Published: December 2021

The physico-mechanical properties of composite electrochemical coatings (CEC) nickel-cobalt-aluminum oxide were investigated depending on the electrolyte parameters and electrolysis conditions. The previously developed low-concentration chloride electrolyte for nickel plating was used as an electrolyte to replace environmentally hazardous chromium plating electrolytes containing hexavalent chromium, which is prohibited by the laws of many countries. The wear resistance of the obtained CEC was determined on a three-ball friction machine. This made it possible to establish that the wear resistance of the CEC exceeds the wear of chrome coatings in dry friction mode by 2-2,5 times and is comparable to chromium in the friction mode with lubrication. In the dry friction mode, the higher wear resistance of the nickel-cobalt-alumina coating is explained only by the higher hardness of the latter. Probably, upon destruction of the coating, the particles of the alloying addition act as a solid lubricant, which causes an increase in the resistance of the CEC during wear. The microhardness of the CEC was determined using a PMT-3 microhardness tester and amounted to 6-25 GPa. The microhardness value was influenced by the concentration and properties of the dispersed phase, as well as the electrolysis conditions - the temperature and pH of the electrolyte, and the cathode current density. “Corrodcote” test was used in the study of corrosion. According to its data, the corrosion resistance of CEC is 2-3 times higher than the corrosion resistance of chromium deposits. The results obtained make it possible to recommend the developed functional CEC of nickel-cobalt-alumina instead of chromium coatings as corrosion- and wear-resistant.
Influence of alloying components on diffusion and bonding processes in powder materials
Authors: Egorov M , Egorova R , Atrohov A , Ekilik V
Published: December 2021

At present, powder materials are used in practically all branches of industry, from medicine to aerospace technology. This is a wide range of materials ranging from constructional and instrumental materials and ending with special-purpose materials and medical implants. Powder metallurgy methods are most often used where the manufacture of products with desired properties is impossible using traditional methods: casting, stamping, etc. The production of all these materials is based on such basic operations as: obtaining starting materials, molding from these materials blanks of a given shape, size and strength, and sintering, intended for the final formation of the required properties and dimensions. The peculiarity of powder metallurgy technology allows creating a huge variety of developed technological schemes, which puts these technologies to a new level and allows for the rapid development of many industries. Alloying powder steels, in contrast to cast steels, has a number of characteristic features due to the specificity of their production. The structure of powder alloy steels and their properties depend on the methods of obtaining steels and technological features of their production. The following main methods of obtaining powder alloyed steels can be named: preparation of multicomponent mixtures of powders of iron and alloying elements and their subsequent processing; the use of alloyed iron powders, to which, if necessary, add carbon or other alloying elements; impregnation with liquid alloying metals or diffusion saturation of frameworks sintered from iron powders.
Kinetics of the formation of a diffusion layer on AISI 1045 steel with simultaneous saturation with boron, chromium and titanium
Authors: Lygdenov B , Guriev M , Ivanov S , Guriev A
Published: December 2021

Research has been carried out to determine the kinetics of coating formation on AISI 1045 steel with diffusion saturation with boron, chromium and titanium simultaneously. It was found that the experimental parameters of the thickness of the diffusion layer of borides over time outstrip the calculated values. The diffusion layer has a thickness of 120 μm with a saturation duration of 2.5 h, 155 μm with a saturation duration of 5 h, and 180 μm with a saturation duration of 7.5 h. In addition to studying the kinetics of the formation of a diffusion coating, also studied the distribution of microhardness over the cross section of the diffusion coating. The maximum microhardness of the diffusion coating is observed not on the surface, but at some distance from it. On average, at a depth of 45–60 µm from the surface. In this case, the microhardness on the surface of the diffusion coating, on the contrary, tends to take on a minimum value of about 1800 HV0.1. Such a distribution of microhardness it gives the parts the possibility of minor surface wear.
Estimation of the chemical resistance of polyurethane compounds used in the manufacture of diaphragms of diaphragm-piston pumps
Authors: Dorokhov A , Kataev Yu , Sviridov A
Published: December 2021

This study presents chemical resistance tests for three different grades of polyurethane bicomponent compounds: PolyFlex 80A, Silagerm 6080 and Advaform Mark 80. Samples of polyurethane bicomponent compounds were prepared in the form of squares, with a thickness not exceeding 3 mm. They were placed in previously prepared containers with aggressive technical me-dia: Lazurit herbicide, Rakurs fungicide and MAXCUT HD SAE 30 mineral motor oil. These technical media were selected taking into account the processing of agricultural legumes, and the concentration of preparations was calculated specifically for soybeans. The selected mineral motor oil MAXCUT HD SAE 30 is used in many pumping equipment used in the agri-cultural industry. According to the results of the study, it was proved that the greatest effect on the samples is exerted by the herbicide “Lazurit”, in which they swell and increase in weight. The experiment carried out to evaluate the chemical resistance of polyurethane compounds showed that the best materi-al for the manufacture of diaphragms used in piston diaphragms is Adva-form Mark 80. This type of two-component polyurethane compound has the best chemical resistance to the investigated chemically active substances.
High-performance process fluids used for vibration finishing of parts with granular media made of natural material “Baykalit”
Authors: Lebedev V , Shumyacher V , Kolganova Ye , Krivosheev D
Published: December 2021

The results of studies of the technological capabilities of granular media made of natural material “Baykalit” in the conditions of vibration technological systems are presented. Baikalit is a siliceous rock-fine-grained quartzite (microquartzite) - with an aggregate structure of quartz grains measuring 1.5-3 microns with sharp boundaries between these very grains. The granules obtained as a result of crushing the mineral rock Baikalit have a sufficiently high hardness (at least 6.0 - 7.0 on the Mohs scale). The presence of many wedge-shaped vertices along the perimeter of the granules and the arbitrariness of the shape allows us to consider them as a universal cutting tool that has access to various surfaces of complexity. It is shown that vibration treatment with granular media made of natural material “Baykalit” reduces the height of the initial surface micrprofile by 0.2-0.3 microns and is an effective way to remove burrs when processing parts with a surface microprofile height of more than 0.63 microns. The use of process fluids, which include increasing the wetting capacity of both Baikalit and processed workpieces, reduces the technological time of vibration processing by 1.5 times. The presence of components in the process fluid, such as protective colloids (Na CMC), prevents the sludge from sticking to the galtovochnye bodies, that is, prevents the “salting” of their profile, reduces the rigidity of the layer on the surface of the galtovochnyh bodies and workpieces, which contributes to productivity growth.
Arctic transmission oil
Authors: Boiko M V , Sidashov A V , Boiko T G , Bicherov A A
Published: December 2021

The tasks of the development of the Far North, the Arctic and the Antarctic require ensuring the operability of equipment units in low temperatures. To solve this problem, it is necessary to develop lubricants using new synthetic oils, a distinctive feature of which are low pour points. On the basis of polyethylsiloxane fluid and petroleum oil, we have developed a gear oil for the Arctic latitudes, which is efficient at temperatures down to -75 ° C (TMarktic). It is shown TMarktic’s antifriction properties are better than those of TSgip helicopter tail gear oil. The combined use of XPS and IR-Fourier methods for the analysis of the friction surface made it possible to conclude that the formation of the boundary film involves both antiwear additive molecules, which are part of the modified oil, due to the P-O, P=O, S=O bonds, so and molecules of polyethylsiloxane liquid due to C-O and Si-O bonds. Secondary surface structures are formed by TMarctic oil on the surface of iron oxide and include hydrocarbon and siloxane fragments. The high antiwear and extreme pressure properties of TMarktic are due to free sulfur and bound in iron sulfide.
Production of corundum armored ceramics
Authors: Pletnev P , Nepochatov Yu
Published: December 2021

The purpose of this study was to develop the compositions and technology of corundum armored ceramics with high ballistic characteristics based on aluminum oxide with an α-Al2O3 content of more than 99 wt.%. The results of the study of the physicochemical processes of obtaining corundum ceramics modified with complex additives consisting of magnesium - aluminosilicate eutectic mixture and oxides of magnesium, yttrium, titanium, zirconium are presented. The introduction of complex additives into the composition of corundum ceramics provides a significant reduction (100-150°C) of the sintering temperature of the product. In this case, additives of yttrium and zirconium oxides contribute to the formation of a uniform-grained microstructure of ceramics, and in the case of adding titanium oxide, a collective recrystallization of corundum grains is noted. The use of small additives (0.3-0.5 wt.%) of magnesium and yttrium oxides together with a eutectic mixture in the compositions of corundum ceramics based on high-quality alumina contributes to the formation of a uniform-grained, dense structure of the material and giving it a high level of physical and mechanical properties as a result of directional the action of each component of the additive on the physicochemical processes of phase formation of the crystalline matrix. A model idea of the mechanism of action of additives on the formation of the microstructure of ceramics during stage-by-stage heating from 1350 to 1650°C in the sintering mode of products is presented. The developed compositions and technologies of corundum armored ceramics have a production focus and implementation in practice.
Principles of obtaining light permeable conglomerate materials based on wood filler
Authors: Pichugin A , Khritankov V , Tkachenko S
Published: December 2021

Recently, the world has seen a demand for transparent or translucent concrete, capable of performing both, structural functions and decorative - design tasks. Such concrete use opens up new opportunities for the creative searches of designers, allows inclusion of new materials in those elements of decorating the internal and external of buildings, structures, large and small architectural forms. The research results on obtaining a new translucent material in the form of wood concrete (arbolite), which makes it possible to introduce previously unused wood processing waste of low-value wood species - birch and aspen into the technological process are presented in the article. The primary results open up new possibilities for light-conducting concretes at significantly low economic costs of their production. The results allows us to conclude about the complexity and ambiguity of wood bleaching processes and the need to strictly follow optimal formulations, modes and compositions at all stages of production.
Research of the mineral additives influence on aggregative stability of foam concrete mixture
Authors: Bartenjeva E
Published: December 2021

An effective method for increasing the aggregate stability of non-autoclave heat-insulating foam concrete is proposed. This material is prepared using a two-stage technology on a turbulent-type installation. An increase in the stability of the foam in the mortar mixture by 9.5-23% has been established. An increase in the viscosity of the foam concrete mixture by 13.5% was revealed. Wollastonite and diopside are actively involved in the formation of a stable structure of foam concrete and are structurally modifying centers. The introduction of mineral additives contributes to the formation of a homogeneous stable structure of non-autoclave foam concrete. Thus, an increase in the stability of the cellular system in the technology of non-autoclave cement-ash foam concrete is possible due to the control of the processes of structure formation when using dispersed mineral additives of wollastonite and diopside. Due to the structural-modifying effect of additives as crystallization centers for neoplasms, a more complete hydration of the cement and a strong contact of the additives with the cement stone should be ensured
Modeling the properties of lightweight polymer concrete produced from polyvinyl chloride and combined heat and power plant waste
Authors: Khristoforova I , Khristoforov A
Published: December 2021

Although concrete based on mineral binders is most commonly used in construction, polymer concrete is on the rise lately. This is due to the fact that polymer concrete allows to expand concrete usage in civil and industrial construction thanks to its properties. However, there is extensive research on including thermoplastic polymer. Construction polymer concrete materials have high compressive strength, as well as atmospheric, cold and chemical resistance, thus resulting in long term lifetime. This paper suggests a technological process of producing concrete based on polyvinyl chloride and lightweight porous aggregate, e. g. fly ash that comes from Vladimir combined heat and power plant (used to run on coal). There are up to 80 thousand tons of this aggregate in stock. It turns out that technological parameters of this process are strongly intertwined with compound. Research indicates that lightweight polymer concrete based on polyvinyl chloride and fly ash can be achieved under certain technological parameters. A new polymer concrete was created as a result of this research having the following properties: density - 800-830 kg/m3, compressive strength - 12-13 MPa, impact strength -16-18 kg/m2, coefficient of thermal conductivity - 0.16-0.18 Wt/m.K, frost resistance - at least a 100 cycles.
Modification of a bituminous binder using waste products from the polymer industry
Authors: Timakov E A , Panov Y T , Vihrev A V , Provatorova G V , Timantsev Y A
Published: December 2021

In this paper, we have investigated the possibilities of the modification of bituminous mixtures using recycled plastic. Waste from enterprises that process plastic is a serious danger to the environment, which is why the need to develop technologies for their processing is not in doubt. The economic advantages of using such additives are that the modifier used is the total waste of industrial enterprises that manufacture products from thermoplastics. Thus, it is possible to solve several problems at once: reducing the cost of production of bitumen; improvement of their physical and chemical characteristics and recycling of non-recycled waste. Patent information on the use of thermoplastics as a bitumen modifier was analyzed. During the work, waste from the extrusion industry of high-pressure polyethylene (LDPE) used. The influence of additives on the basic physical parameters of bitumen is shown. In the course of research, it was found that the addition of 2-3% polymers to the original formulation allows us to obtain bitumen, the main physical parameters of which (penetration, ductility, softening) meet the existing requirements. With this method of bitumen modification, the cost of their production is reduced without deterioration of the properties of the finished product. We also investigated the possibility of introducing up to 25% modifiers into the formulation, for maximum utilization of polymer waste. The bitumen obtained in this way can be used in regions with a hot climate. An important fact is the unification of the method of introducing additives into the existing technology, which does not require its change. The results of the study showed that thanks to the results obtained, it is possible to significantly reduce the cost of producing asphalt and bitumen products, expand the technological properties of finished road surfaces, and solve the problem of recycling plastic waste.
Investigation of physical, mechanical and tribological properties of corrosion-resistant steel with laser surface surfacing of WC100Co4Cr
Authors: Zhdanov A V , Dovbysh N S , Belyaev I V , Morozov V V
Published: December 2021

The article investigated the effect of laser surfacing of WC100Co4Cr powder on the surface of corrosion-resistant steel on hardness, tensile strength and yield strength, coefficient of friction and the amount of wear of products made of alloy structural cryogenic steel. The SVAROG-1-5DR laser complex (Russia) was used for laser processing. Various modes of surface laser surfacing were set. For this purpose, the power of the laser radiation, the speed of movement of the laser beam relative to the treated surface and the focal length were varied. The measurement of physical, mechanical and tribological characteristics was carried out using the equipment of the company “CSM Instruments” (Switzerland). The structure of the alloy was studied by metallography and X-ray diffractometry. The results showed a significant increase in hardness, tensile strength and yield strength and a decrease in the coefficient of friction.
Modeling of electric mass transfer process in controlled electrochemical resistance
Authors: Fugarov D D , Gerasimenko E Y , Gerasimenko A N
Published: December 2021

The aim of the study is to mathematically simulate the concentration field of an electrolyte in a controlled electrochemical resistance. All processes occurring in the object are considered isothermal, the electric fields in all fragments of the electrochemical resistance are potential, plane-parallel. All physical and chemical parameters of the object’s materials are constant values. The kinetics of all electrode processes in the object of study is controlled by the diffusion stage in the electrolyte. As a research method, the operator method of Laplace and Fourier – expansion is used to obtain an analytical description of the concentration field of the electrolyte. In the course of the study, a mathematical model of the concentration field of the electrolyte with a uniform distribution of the current density was obtained. An analytical expression is obtained that allows to construct the surface of the change in the concentration of the electrolyte in the controlled electrochemical resistance. The concentration profiles of the electrolyte at different temperatures and the time dependences of the change in the concentration of the electrolyte are calculated.
Molecular dynamics study of the influence of uniaxial deformation on the migration velocity of tilt boundaries in nickel
Authors: Poletaev G M , Ziuzin D I , Novoselova D V , Rakitin R Y
Published: December 2021

The molecular dynamics method was used to study the influence of elastic uniaxial deformation on the migration velocity of tilt boundaries with misorientation axes [100] and [111] in nickel. The dependences of the migration velocity at a temperature of 1600 K on the misorientation angle were obtained. It is shown that the high-angle [100] and [111] tilt boundaries migrate at approximately the same velocity, while the low-angle [111] boundaries migrate approximately twice as fast as the [100] boundaries. The obtained dependences of the migration velocity of the boundaries on the value of uniaxial deformation in almost all cases turned out to be nonmonotonic and had a maximum at a tension value of about 1%. With a further increase in tension, migration slowed down, which is most likely explained by a decrease in the surface tension of the boundaries and, accordingly, in the driving force due to the finite sorption capacity of grain boundaries with respect to the free volume. Under elastic compression, in most cases, a monotonic decrease in the migration velocity was observed, which is due to a decrease in free space during compression and a decrease in the mobility of atoms at the boundary.
Modelling of technological process of joining steel ropes with the use of powder antifriction material and a conductor
Authors: Marchenko E V , Korotky A A , Popov S I , Marchenko Ju V , Kosenko E E
Published: December 2021

When determining the causes of structural defects of a steel rope, the technology of carrying out work on splicing by a team of specialists was studied in detail. Field observations and experimental studies, as well as mathematical modeling of the process of structural defects formation in the rope joint section, allowed to establish that the cause is the imperfection of the existing technology for performing splice work [1-5]. The existing technology directly depends on the experience (professionalism) of a splicing team and provides for the work on splicing, as a solution to a new problem for every hawser, expressed in the design and calculation of the main parameters, according to the established standards of the rope manufacturer. It is noted that this labor function negatively affects a person, causing dangerous and harmful factors of the working environment, such as: severity and intensity of the labor process. Under the influence of dangerous and harmful factors, the specialist is subject to: static and dynamic overload, mental overstrain, neuropsychiatric overload, which negatively affect a person and, as a result, affect the quality of the work performed as a whole. The total accumulation of dangerous factors in the course of work leads to the decrease in the quality of the obtained results and deviation from the normalized indicators, which is unacceptable and leads to the formation of structural defects of a steel rope.
Evaluation of the structural stability of welded joints in welding
Authors: Schepkin V , Poletaev Yu
Published: December 2021

Brittle (intergranular) destruction of the heat-affected zone metal (local failure) of welded joints of power equipment during welding and heat treatment (tempering) was an unexpected and serious problem. Its solution based on the development of progressive technological solutions is an urgent task of modern power engineering. The article considers an applied method of fluctuation analysis for assessing the stability of the structure and the probability of local destruction (LD) of the metal of the heat-affected zone (HAZ) of thick-walled welded structures of power equipment made of low-alloy steel 15Kh2NMFA. A computational - experimental method for calculating the range of optimal values of heat input is stated. The LD mechanism is stated and its connection with the technology and thermal conditions of welding and the structural stability of the HAZ metal is established. It was found that the growth of austenite grains of the HAZ metal stimulates the tendency to LD, if a dendrid-type carbide phase is precipitated at grain boundaries during welding. By optimizing the heat input during welding, it is possible to control the structural and chemical homogeneity of the HAZ metal and the associated tendency to form LD.
Determination of short circuit location in the electric railway traction
Authors: Bykadorov A L , Zarutskaya T A , Muratova- Milekhina A S
Published: December 2021

This article discusses the problem of improving the accuracy of determining the location of a short circuit in the AC railways traction networks. Finding a short circuit can take several hours. An urgent task is reducing the time to search for a fault location. The purpose of the study is to develop a method that increases the accuracy of determining the location of a short circuit in AC traction networks. The method is based on computer modeling of inhomogeneities in the structure of the traction network and the arc. The proposed method makes it possible to take into account the arc resistance. The method was tested on the traction network active section. The error of the method is 200-300 meters. The method can find practical application in the work of dispatchers.
Automation of ac electric-traction NetWare digital protective relay operational control
Authors: Kubkina O V , Lysenko V G
Published: December 2021

The widespread use of microprocessor-based digital protective relay from various manufacturers, the expansion of the programmable protective relay terminals’ functional composition, the lack of hardware, software and algorithmic support unification, problems of electromagnetic protection necessitate consideration of the issues of digital protective relay operational control automation [1-3]. The authors believe that the attention paid by operating services to the means and methods of the AC electric-traction netware protective relay Functional check is insufficient. Monitoring the correct protection functioning in real time when it is triggered by a short circuit makes it possible to identify all types of incorrect actions of the instrument units until the failure of the entire protection as a whole. The most common failures, such as “false response” and “unnecessary operation”, are detected with a probability close to unity [4-6]. The article discusses the principles of building a system of protective relay Functional check, applicable for all types of electric-traction netware protection that are currently in operation. Logical equations are given to identify incorrect actions of protective relay.
Modeling and calculation of SC currents for alternative group grounding system for the dc contact line supports
Authors: Osipov V A , Osipova A I
Published: December 2021

The problem of creating a mathematical model of the group grounding system of the contact line supports is considered. The paper considers an alternative way of organizing group grounding. For such a method of grounding, a model of a section of a DC railroad is proposed, which makes it possible to calculate the SC current. An analysis of the constructed model quality is carried out, an assessment of the calculation error according to the proposed method is given.
Application of the recurrent mathematical model for estimating the electric-traction NetWare parameters at their dynamic change
Authors: Kapkayev A A
Published: December 2021

The article is devoted to the possibility of applying the methods of successive approximations in the analysis of the instantaneous scheme of the electric-traction netware. The described approach makes it possible to improve the accuracy of modeling the dynamic modes of traction power supply sections operation, and also makes it possible to significantly improve the process of modeling diagnostic and control systems for electric rolling stock at the design stage, based on a more accurate model of dynamically changing input parameters of the electric-traction netware, depending on their required level.
Application of the train congestion recovery method for constructing an instantaneous direct current railway section
Authors: Osipov V A , Logunova P A
Published: December 2021

Improving the energy efficiency of the transportation process is one of the key tasks, the solution of which is one of the priority areas of the holding JSC «RZD» research. The successful solution of this problem depends, among other things, on the effectiveness of measures taken to reduce energy losses arising from electricity transmission to the consumer, which is the rolling stock of electrified railways. To develop a set of organizational and technical measures aimed at minimizing electricity consumption, an effective apparatus that provides determination of energy losses amount of in the electric-traction netware in real time is needed. The article proposes a method for hardware-analytical calculation of energy losses, which is based on an algorithm for processing the results of direct measurements. It is proposed to calculate power losses using laws and relationships known from the course of electrical engineering. A distinctive feature of the proposed method is the function of recreating the instantaneous circuit based on the data of currents and voltages measurements at the control points of a given section. The proposed method is suitable for use exclusively on DC electrified railways. Also, the paper presents the methods for determining energy losses used today in Russia, and gives their brief characteristics. The logical and mathematical apparatus of the method is described in detail, indicating the possible reasons that, in the process of synthesizing instantaneous circuits, can affect the occurrence of errors. An assessment of the study results of this method application in the electric-traction netware of railways is given.
Estimation of the domestic materials application possibility in the active part of a high-speed electric generator for micro-GTP
Authors: Kolpahchyan P G , Podbereznaya M S , Alexandrova M S , Baibichyan V V
Published: December 2021

The article discusses the possibility of using domestic materials in a high-speed electric generator. The features of Japanese electrical steel 20NTN1500 and domestic-made electrical steel grades 2420 and 2421 for the stator magnetic circuit are shown. The features of American steel AISI 455 and structural steel grades Steel 40, Steel 40H, Steel 45 are considered in the case of a rotor. A feature of the use of structural steels in the design of the high-speed electric generator rotor for micro-gas turbine plants is the need for precise observance of the rotor heat treatment mode after its manufacture, control of the dimensions and quality of surface treatment.