bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the efficiency of aerodynamic dampers based on preliminary numerical modeling
Authors: Churin P , Pomelov V 
Published: December 2021

Abstract
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

Abstract
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

AbstractThe 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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.