bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some aspects of the nitriding process of parts in machine construction
Authors: Mazuru S , Trifan N , Mazuru A 
Published: January 2021

Abstract
Nitriding is the most common and effective surface hardening method. Such chemical-thermal treatment is capable of increasing surface hardness, contact endurance, wear and seizure resistance, as well as heat resistance and corrosion resistance of a wide range of machine parts. This process of surface hardening has found its application in many branches of modern mechanical engineering. The operational requirements for the parts led to the need to replace high-temperature methods of chemical-thermal treatment (carburizing, high-temperature nitrocarburizing, etc.) for hardening processes at lower temperatures (500-650° C), namely nitriding. This replacement was facilitated by the latest technological developments in the field of various nitriding methods. The scientific developments obtained to date make it possible to gradually eliminate such disadvantages of nitriding as a significant duration of the process, increased fragility of the surface layer, insufficient values of contact endurance, and labor intensity of the process [1, 2].
Smart prediction of surface micro-hardness after milling based on fuzzy inference model
Authors: Amira M T , Belloufi A , Abdelkrim M , Abdelkrim F , Mezoudj M 
Published: January 2021

Abstract
The lack of comprehending and control of the micro-hardness of the machined surface is an important obstacle to the use of the milling process. In order to optimize the machining process by milling, this work has focused on the problem of micro-hardness changing of machined surfaces by milling, which has been the subject of several scientific works. A fuzzy inference model was developed to study the influence of cutting conditions (cutting speed, feed per tooth and depth of cut) on the micro-hardness of machined surfaces by milling. The predicted values, obtained by fuzzy model, are compatible with the experimental values, with an average error percentage of 0.63%.
Experimental study towards WIG welded joint. Case study: Repair by welding of X2CrNiMo17-12-2 pipes
Authors: Ionescu F , Solomon Ghe , Voiculescu I , Gârleanu G , Gârleanu D 
Published: January 2021

Abstract
Nowadays, several technological problems were raised by industrial beneficiaries regarding spiral and pipe heat exchangers repairs and thus studies were done in this regard. X2CrNiMo17-12-2, austenitic stainless steel pipes were considered for the experiments on which artificial defects, simulating functioning defects, were done. In order to perform the repair activities on the designed defects, WIG welding process was used and an experimental stand was created. This paper presents some of the difficulties that can occur during the repair by welding of pipes and the defects identified using destructive and non-destructive testing on the probes and samples created for the experimental study scope. Significant conclusions can be drawn; up to a distance of about 100 - 150 mm from the access end, the repair has a good appearance with no serious imperfections.
The composite functional statistical criterion for evaluating the effectiveness of the automatic control process and system
Authors: Akimov A I , Akimova J A , Panchenko V V , Odiehov M M 
Published: January 2021

Abstract
The process of managing and controlling equipment is a broader concept than data transmission. It includes collecting the information about the controlled parameters, transferring the information, its processing, the development of control actions and their transfer to the object in order to bring the controlled parameters back to normal. These tasks are solved by the control and monitoring system. Modern ACMS have not only a larger number of elements, but also a more complex internal structure. Even if all elements of ACMS function are in a reliable way in the process of its operation, the performance of the task assigned to the system cannot be treated as a reliable event. One of the essential features of ACMS is that they are meant to improve the quality of the controlled objects. To quantify the quality of complex systems, effectiveness indicators are used. Indicators of the quality of the system performance of the assigned functions are called the effectiveness of system operation or simply effectiveness. The main idea of evaluating the effectiveness of ACMS is to get the opportunity to compare systems that are identical in purpose, even if they differ from each other in the principles of design and operation. There are certain connections between the individual elements of ACMS, the system as a whole and the controlled object through which they interact with each other. From the point of view of evaluating ACMS effectiveness, the information content of these links is crucial, since the processes of automatic control, for example, in the field of electrical energy production and distribution, are carried out on the basis of information received about the controlled object.
Determination of parameters for automatic decompression of heat and power facility cylinders
Authors: Anatskyi O O , Aulin D O , Bobrytskyi S V , Zhovtiy Y V , Chernenko P V 
Published: January 2021

Abstract
This paper analyzes various types of startup systems used for the heat and power facility start-up. Factors impacting startup characteristics of the heat and power facility were considered. Methods for the modernization of the startup system and possible revamping of auxiliary starting aid devices of locomotive diesel engines without significant design changes by means of cylinder test valve opening were identified. Kinematic diagrams of device gearing for automatic decompression of the heat and power facility cylinders were developed and analyzed. The device requirements were determined, namely, response time, cylinder test valve open and closing torque overriding Tmin=11 Nm. Based on the necessity of torque backup at least 30 % the gear ratio required for the selected engine and its dimensions was calculated.
Determination of rational locomotive operating modes and resource costs based on information from global positioning systems
Authors: Barybin Mykola , Falendysh Anatoliy , Hatchenko Victoria , Kletska Olha , Kiritseva Elena 
Published: January 2021

Abstract
The article is devoted to the study of energy-efficient use of traction rolling stock for driving trains. It deals with the optimal driving mode and the main parameters of traction calculations. Based on the use of GPS/GLONASS satellite navigation units, a method for determining the basic resistance of cars in real time is proposed. The possibility of using the results obtained on locomotives with analog devices and no movement tracking is analyzed. The “Traction Calculations” software package in the C# programming language was modified in order to reduce the time and facilitate calculations of the locomotive traction service. In the course of the study, the equation of the main resistance of the cars of train No. 3612 was determined. On the basis of the uncoupled rolling stock, the dependences of speed, time, heating and current of traction electric motors, fuel consumption by the CHME3 locomotive of the Kharkiv-Sortirovochny locomotive depot for the transportation of cars from the Kharkiv-Sortirovochny station to Merefa station were calculated, with recommendations for the driver to use the position of the driver’s controller in order to reduce costs and fulfill the train schedule.
Improvement of the method of probability evaluation of the failure-free operation of reinforced concrete beams strengthened under load
Authors: Ye Khmil R , Yu Tytarenko R , Blikharskyy Ya Z , Vegera P I 
Published: January 2021

Abstract
The article is dedicated to the study of the load level effect on failure-free operation probability of undamaged rectangular cross-section reinforced concrete beams when their strengthening by the tensile steel reinforcement increasing. The presence of the load level simulates the real structure exploitation conditions at their strengthening. The validation of basic and improved reliability evaluation methods on real beam samples allowed receiving the recommended failure-free operation values P(β). Both techniques are adapted to national standards for the reinforced concrete structure design. The difference between the techniques is the operating method of the random parameter of the load level at the moment of amplification. According to the results of approbation the comparative analysis of the received results is carried out – depending on additional steel bar diameter and the load level at the moment of amplification. The practical significance of the article results is in use of both existing and advanced methods of the probabilities of failure-free operation estimation of reinforced concrete bended elements, strengthened by addition of the stretched steel reinforcement under different load levels, in particular, for accepting higher design levels of reliability.
A study of bearing capacity of reinforced masonry beams with GFRP reinforcement
Authors: Kramarchuk Andrii , Ilnytskyy Borys , Bobalo Taras , Lytvyniak Oksana 
Published: January 2021

Abstract
This article presents the results of experimental researches of bearing capacity and deformability of reinforced masonry beams with combined reinforcement. This study was carried out in the zone of maximum bending moment. The reinforcement A400C and A1000 were used for experimental samples. The combined action of ceramic masonry and reinforcement was ensured at the expense of a cement-sand grout in the joints of masonry and vertical reinforcing meshes in support zones of beams, which were welded to angle bars. Besides that, there was carried out a comparison of the results of experimental researches with calculated values by the active standards of Ukraine. This comparison permits to determine the expediency of the use of the existing design procedure of bearing capacity of reinforced masonry structures with combined double reinforcement. Finally, this scientific work has also presented the conclusions about the possibility of the efficient design of reinforced masonry structures in the effective area of normal forces.
Research of Disclosure of Relief Venting Structures with Polycarbonate Fencing in Conditions of Explosion
Authors: Pozdieiev Serhii , Nizhnyk Vadym , Pidhoretskiy Yuriy , Shvydenko Andriy 
Published: January 2021

Abstract
The article considers the processes of release of the openings of relief venting structures based on honeycomb polycarbonate sheets under action of an explosion. The use of honeycomb polycarbonate sheets enables saving transparent fence against destruction, decreasing risks of human traumatism with glass shards, reduce weight of relief venting structures. There were investigated the conditions of the ratio of the opening sizes of the sections of relief venting structures with honeycomb polycarbonate sheets, under which this opening is reliably released to reduce the pressure during the explosion to safe values. A mathematical model was proposed that establishes a relationship between the value of the explosion pressure and the opening size at which the opening of relief structures with honeycomb polycarbonate sheets. The article proposes a calculation method for designing the sections of relief structures with honeycomb polycarbonate sheets using nomograms. The use of developed method lets significantly simplify calculating for design of relief structures with honeycomb polycarbonate sheets.
Features of determining engagement line of traction gears with different degrees of wear of gear teeth
Authors: Moroz V I , Hromov V I , Bratchenko O V , Logvinenko O A 
Published: January 2021

Abstract
Calculations of strength, forecasting the residual operation life for repairing traction gears (TG) is carried out on the results of modeling their motion characteristic, which is based on the determined coordinates of the contact points of the gear and wheel profile for the period of engagement (engagement line). This article presents results of a study aimed at developing mathematical dependencies for a refined determination of TG engagement line with the established wear of gear teeth. Adequacy verification of proposed mathematical descriptions was carried out based on the results of the study of new TG of ER-2 electric train series. Their comparison with the coordinates of the engagement line, calculated by the traditional method, showed that modelling uncertainty does not exceed 0.06%. As an example of practical use of the received mathematical descriptions, results of research of motion characteristic of new TG of ER-2 electric train series with the established degrees of wear of gear and wheel teeth are presented.
Ways to increase the traction efficiency of modular draft device
Authors: Nadykto V , Kyurchev V , Chaplinskyi A , Ayubov A 
Published: January 2021

AbstractThe versatility of tractors can be increased by using them as a part of a modular draft device (MDD). MDD consists of energetic (EM) and technological (TM) modules. EM is a high-energy tractor with a 2WD or 4WD wheel arrangement and a traction force of 14-16 kN. TM is an additional axle with an active drive of its wheels. By connecting TM to the rear hitch linkage (RHL) of EM, the tractive effort of the entire MDD, which has a 4WD or 6WD wheel arrangement, increases to 32-36 kN. MDD can function as a road-rail vehicle. Depending on the traction resistance, MDD can be used both as part of an EM+TM or as a single EM. According to the research results, it was found that the maximum traction efficiency (TE) of MDD with a 6WD wheel arrangement is about 10% higher than that of MDD with a 4WD wheel arrangement. The TE value of MDD increases with an increase in the inclination of EM rear hitch linkage top link. The increase in MDD’s tractive efficiency is facilitated by an increase in the coefficient of kinematic discrepancy in the drive of the EM and TM wheels from 1.00 to 1.05.
Justification of the parameters of the life-test bench for railway wheelsets
Authors: Raksha S V , Anofriev P G , Kuropiatnyk O S 
Published: January 2021

AbstractOne of the tasks that need to be solved in order to predict the life of wheelsets is to assess the contact strength and wear of their parts. Thus, the purpose of this work is to develop a scheme and justification of the parameters of the life-test bench for railway wheelsets in conditions close to real operating ones. This bench simulates a contact of “wheel-rail” pair as a contact of “wheel-roller” pair. To ensure compliance of the bench tests conditions with the real wheelsets operation conditions we took that the maximum contact pressure in the “wheel-roller” pair is equal to the maximum contact pressure in the “wheel-rail” pair. As results of this study we obtained the dependences of the values of the roller diameter and the working force of the bench on the characteristics of the tested wheelset and proved the mutual influence of these quantities. For railway wheelsets with an axle load of 230.5 kN and wheels with a tread diameter of 957 mm, we obtained the following values of the bench parameters: roller diameter is 75 mm; working force of the bench is 8,375 kN; wheel speed is 500 rpm; number of rollers is 8; test duration is about 220 h.
Mathematical modeling of dynamic loads on the ground robotic complex of special purpose
Authors: Strutinsky V B. , Gurzhii A. M. , Yurchyshyn O. Y. 
Published: January 2021

Abstract
A special technique to study the impact of the discharge on the ground robotic complex equipped with small arms in this article is proposed. The development of the technique is based on mathematical modeling of the dynamic system of the robotic complex. The magnitude and nature of dynamic loads on the ground robotic complex are determined. The experimental sample of the ground robotic complex equipped with small arms has been developed by the authors. Measures to ensure a stable position of the complex and methods of compensation for uncontrolled changes in the position of the complex under dynamic loads are proposed. To study the processes of firing, their individual components are considered: the problem of internal ballistics, the process of movement of the retractable parts of the barrel, dynamic loads on the complex. The conducted study gives the chance to create highly effective samples of special equipment. These are, in particular, military ground-based robotic complexes, which will be competitive by increasing the efficiency of their operation.
Determination of the influence of soil irregularities on dynamic processes in caterpillar engines of a terrestrial robotic complex
Authors: Strutynskyi S V , Semenchuk R V 
Published: January 2021

Abstract
The paper describes the change of the geometry of the caterpillar of the terrestrial robotic complex depending on external factors. It is established that as a result of the action of centrifugal forces the caterpillar elongates, on the surface of the support rollers, the caterpillar repeats their shape, the upper part of the caterpillar acquires a convex shape, and the lower part of the caterpillar repeats the shape of the curve, which determines the unevenness of the soil. The dependence of the caterpillar shape on soil irregularities is established. The peculiarity of the geometry is that on the lower part of the caterpillar there is a ripple with the number of waves between the support rollers 1-2. It is established that the presence of soil irregularities, the harmonic components of the profiles of which have a period of about 4/3 of the distance between the extreme support rollers, leads to the greatest tensile loads in the caterpillar and the corresponding changes in caterpillar length. The dependences determining the elongation of the caterpillar, which is proportional to the square of the amplitude of the harmonic component of the soil roughness of the corresponding period are obtained.
Piezoelectric networks and ferroelectric domains in twistronic superlattices in WS2/MoS2 and WSe2/MoSe2 bilayers
Authors: Enaldiev V V , Ferreira F , Magorrian S J , Fal’ko Vladimir I 
Published: January 2021

Abstract
Twistronic van der Waals heterostrutures offer exciting opportunities for engineering optoelectronic properties of nanomaterials, in particular, due to the formation of moiré superlattice structures. In twisted bilayers of transition metal dichalcogenides moiré superlattice effects are additionally enriched by the lack of inversion symmetry in each monolayer unit cell. Here, we use multiscale modelling to establish a rich variety of confinement conditions for electrons, holes and layer-indirect excitons in twistronic WX2/MoX2 bilayers (X = S,Se). Such trapping of charge carriers and excitons is caused by ferroelectric (interlayer) polarisation and piezoelectric effects generated by the reconstruction of twistronic bilayers into preferential stacking domains separated by domain wall networks. For almost aligned bilayers with anti-parallel (AP) orientation of WX2 and MoX2 unit cells, we find that upon lattice relaxation piezoelectric potential modulation traps holes and electrons in the opposite corners—WMo and XX (tungsten over molybdenum versus overlaying chalcogens)—of hexagonal-shaped 2H (simultaneously WX and XMo) stacking domains, swapping their positions at a twist angle

≳

0.2∘. This crossover happens at such small angles (set by a very small lattice mismatch between WX2 and MoX2) that would impose an alignment accuracy and homogeneity better than 0.1∘ for achieving reproducibility of electronic characteristics of such heterostructures. At the same time, for all angles, XX corners provide 30 meV deep traps for the interlayer excitons. In bilayers with parallel (P) orientation of WX2 and MoX2 unit cells, band edges for both electrons and holes appear in triangular domains, where WX2 chalcogens set over MoX2 molybdenums. We find that, due to a weak ferroelectric polarisation, these triangular domains act as 130 meV deep quantum boxes for interlayer excitons for twist angles

≲

1

∘

, shifting towards XX stacking sites of the domain wall network at larger twist angles.
Effects of Nb concentration and temperature on generalized stacking fault energy of Zr–Nb alloys by molecular dynamics simulations
Authors: Wang Hailian , Pan Rongjian , Tang Aitao , She Jia , Mi Xiaoxi , Wu Lu , Tan Jun 
Published: January 2021

Abstract
The effects of Nb concentration and temperature on the generalized stacking fault energy (GSFE) of basal, prismatic I, pyramidal I and II plane for Zr-Nb alloys are investigated by molecular dynamics simulations (MD). The stable and unstable SFEs of different slip systems show no significant change with the increasing Nb concentration (0, 0.5, 1.0, 1.5, 2.0, and 2.5 at.%) in Zr-Nb alloys at 0 K. Basal, pyramidal I and II planes slip of Zr-Nb alloys prefer to deform by full dislocation with the temperature increases. Additionally, plastic deformation anisotropy of Zr-Nb alloy is improved with the increasing temperature using both embedded atom method (EAM) and angular-dependent potentials (ADP). The present work provides a theoretical basis for understanding enhanced plasticity of Zr-Nb alloys under finite temperature.
Gelatin/Gelatin-modified nano hydroxyapatite composite scaffolds with hollow channel arrays prepared by extrusion molding for bone tissue engineering
Authors: Chen Xiliang , Wu Di , Xu Jingjing , Yan Tingting , Chen Qinghua 
Published: January 2021

Abstract
Bone tissue engineering scaffold has been successfully applied in the field of bone repair, but the major limitation is the delivery of oxygen and nutrients throughout the bulk of engineered tissue, especially for large scaffolds. Researchers have found that scaffolds with hollow channels can effectively solve this problem. We utilized a novel extrusion approach to prepare scaffolds with hollow channel arrays, which has the advantages of economy, continuous production, and high efficiency. The hollow channel scaffolds were composed of gelatin and gelatin-modified nano hydroxyapatite (nHAP). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and atomic force microscope (AFM) results indicate that the prepared gelatin-modified nHAP are nanorod-like particles with the length of 30∼50 nm and width of 5∼15 nm. The nano particle is composed of crystalline HAP grains with the size less than 10 nm and amorphous phases. A part of OH− or

PO

4

3
−

are replaced by

CO

3

2
−

during preparation process, leading to the transformation of HAP into hydroxyl-carbonated apatite (HCA). The prepared hollow channel scaffolds exhibit much better mechanical properties compared with the sponge porous scaffolds. The axial compressive strength of the hollow channel scaffold with porosity of 51.3 ± 5.2% can reach 25 ± 1.4 MPa, which can meet the mechanical strength requirement as an implant completely. Moreover, the hollow channel scaffold exhibited good in vitro degradability and bioactivity. These results highlight the potential of using gelatin/gelatin-modified nHAP composite scaffolds with hollow channels for bone tissue engineering.