bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developing a drilling fluid compensator for increasing the technological condition of drilling equipment
Authors: Minnivaleev T N , Minnivaleev A N 
Published: March 2021

Abstract
The phenomenon of fluctuations in pressure and fluid flow, as well as hydraulic shocks in most cases lead to negative consequences that affect the technical condition and operation of various equipment. The article discusses the causes of pressure fluctuations of the flushing liquid in the drill string and their consequences, and provides a developed compensator for the flushing liquid, which allows to smooth the flow pulsation.
Methods for increasing the efficiency of hydrochloric-acid treatments of wells
Authors: Mukhametshin V V , Kuleshova L S 
Published: March 2021

Abstract
The authors generalize the experience of conducting hydrochloric-acid treatments in the wells of high-viscosity oil deposits with hard-to-recover reserves in carbonate reservoirs. Intervals of changes in the values of geological and technological parameters with the efficiency of hydrochloric-acid treatment over 50% have been estimated. The impact parameters have been determined in various geological-field conditions. The causes of catastrophic water cut of wells as a result of impact have been established.
The effect of the grain size on the cycle life of spring steel 50 CrMnV
Authors: Pachurin V G , Galkin V V , Filippov A A , Pachurin G V , Mukhina M V , Smirnova Zh V 
Published: March 2021

Abstract
Most of the breakdown of machine parts and metal products during operation is fatigue-related due to the impact of load cycling during operation, which often leads to serious financial losses, and sometimes even fatalities. Therefore, the issues of increasing cycle life are relevant. In this work, we propose a method for predicting the cycle life of spring-type steel: the expected cycle life of steels 50CrMnV and 60SiCr in the range of 105-106 cycles can be preliminarily estimated using the equation depending on the grain size. The method allows predicting the cycle life and significantly reducing the time of its evaluation for steels such as 50CrMnV and 60SiCr by eliminating long-term fatigue tests. In addition, it also allows choosing the best performance from process treatments for the cycle life parameter without long labor-intensive fatigue tests.
Modelling the movement of log trucks with a hydro-mechanical transmission
Authors: Pitukhin E A , Skrypnik V I 
Published: March 2021

Abstract
The paper proposes a mathematical model of the movement of log trucks with hydro-mechanical transmission, which represents the analytical functional dependence of the speed of the log truck on the covered path. On the basis of real data it is shown that the traction characteristic of hydro-mechanical transmission is best approximated by hyperbolic regression. In this case, the solution of heterogeneous nonlinear differential equation of motion can be obtained by the approximate analytical method through decomposition of a logarithmic component in series. The calculation example showed that the obtained approximate analytical solution deviates from the numerical solution by no more than 0.002%. The obtained model allows one to determine the analytical dependencies for speed and time, which can be used to calculate the modes of movement of log trucks with the hydro-mechanical transmission.
The development of microwave installations for separating the fluff from skins of rabbits in the agricultural enterprises of low power
Authors: Shamin E , Novikova G , Mihkailova O , Prosviryakova M , Kirillov N , Storchevoj V , Zaitsev S 
Published: March 2021

Abstract
The article is devoted to the development of technology and technical means designed to weaken the retention force of hair in the dermis of rabbit skins due to selective dielectric heating of hair bulbs under the influence of an ultra-high frequency electromagnetic field (UHFEMF). Microwave technologies and more than 20 installations with UHFEMF sources and non-traditional resonators have been developed that provide continuous collection of fluff from rabbit skins. Resonators have been tested that ensure the separation of downy raw materials from the skin of rabbit skins in a continuous mode when implementing a set of reasonable design and technological parameters. Novelty of technical solutions of developed technologies and microwave installations with non-traditional resonators, such as: cylindrical (2655770, 2651594, 2680543, 2682890); semi-cylindrical (2018101622, 2703918); toroidal (2674605, 2699709); coaxial (2655748, 2651593); biconic (2715341, 2018117136) proved by patents of the Russian Federation. A technical specification has been developed for creating a radio-hermetic microwave installation with low-power magnetrons and a biconic resonator, which ensures the separation of down raw materials from rabbit skins in a continuous mode at low operating costs.
Positioning automation when assembling panel structures
Authors: Kovalevich M V , Shemonaeva E S 
Published: March 2021

Abstract
The article discusses the process of assembling low-stiffness panel structures typical of the aerospace industry. Due to the low stiffness of the incoming elements, the assembly of such structures differs from the assembly of structures typical of general mechanical engineering. To switch to a robotic assembly of such structures, it is necessary to comply with special requirements both to the technology and to the design of the elements included in the assembly. The paper investigates the process of positioning automation during the assembly of panel structures using industrial robots. The article describes a method of verification calculation for accuracy, which allows establishing whether the proposed positioning method meets the specified requirements for the aerodynamic contour of the product. Requirements for structural elements have been formulated, which will allow positioning during assembly with the required accuracy. The results obtained in the course of the study can be used in the design of new structures, the assembly of which will be carried out using automation tools. In addition, the developed requirements must be taken into account when switching to new assembly technologies for existing structures. The results of the study can help to improve the efficiency of assembly of flexible structures used in the aerospace industry. It was also found that it is necessary to conduct further research in terms of the influence of deflections of the structure from its own weight and during the supply of the tool that performs the setting of joints.
Correlation analysis to determine the relationship between the geometric dimensions and the electromagnetic moment of a switched reluctance motor
Authors: Shevkunova A V , Shapshal A S , Talakhadze T Z , Shapshal S A 
Published: March 2021

Abstract
An electric drive is an indispensable part of any mechanism. Without it, the the functioning of any industry is impossible, especially in the railway. It allows you to automate technological processes and increase their efficiency. For efficient railway transport, it is necessary to increase the level of technical development of traction rolling stock, which is possible through the use of promising types of electric machines, one of which is a switched reluctance motor. To create a highly efficient and technological switched reluctance electric drive, it is necessary to have information about the relationship between the geometric dimensions of its magnetic system and the average value of the electromagnetic moment. The purpose of this article is to determine the strength and direction of the relationship between the average value of the electromagnetic moment and the changing geometric values of the tooth-groove zone of the object under study. The numerical value of the electromagnetic moment was obtained using the stochastic method in the MATLAB application package, which directly interacted with the FEMM version 4.2 program, which is based on the finite element method. The research carried out in the article and the results obtained allow us to conclude that there is or is not an appropriate connection between the considered elements of the magnetic system design and the value of the electromagnetic moment.
Selection of optimal operating modes for a block cluster pumping station
Authors: Suleimanov R I , Khabibullin M Ya , Zainagalina L Z , Zaripova L M 
Published: March 2021

Abstract
The article discusses a method for optimizing the model of a modular cluster pumping station using a variable frequency drive. Thanks to this technology, the energy consumption of the pumping units of the installation are sharply reduced. The equipment service life increases as a result of the application of this technology.
Application of the least square method for calculating the optimal well profile
Authors: Usmanova F K , Usmanova L Z 
Published: March 2021

Abstract
The article offers a new approach to calculating a wellbore profile of a directional well. The calculation of the well trajectory based on inclinometric studies using correlation analysis is considered. The coordinates of measurement points are calculated automatically by building a comparison table in Microsoft Excel. Based on the results of calculations, the functional relation the most fully characterizing the well path is selected. We propose the least square method for calculating the optimal well profile. According to revealed functional relation, the length of the well is determined by integration based on the calculated values of displacements. The estimation of wellbore deviation from the well profile design represented as a parabolic dependence at a certain drilling interval was performed.
Design and technological support for the assembly of long thin-walled buildings
Authors: Yamnikov A S , Rodionova E N , Matveev I A 
Published: March 2021

Abstract
The article considers the issue of design and technological support for the assembly of extended thin-walled buildings, in particular, the problem of ensuring their entry into the reciprocal parts that ensure the functioning of the assembled products. A new method for controlling the size of the entry of buildings is proposed. The objective of the technical solution is to reduce the complexity of control of the hulls while ensuring their entry into launch tubes. The method consists in the fact that the housing is installed in two prisms according to the extreme centering thickenings. The readings of the measuring device are taken, which judge the suitability of the housing by the diameter of the adjacent cylinder, characterized in that the indicator is installed in a plane perpendicular to one of the faces of the prism, adjusted according to the standard when touching the tip of the middle centering thickening of the standard. As a result of testing in the conditions of the current production, it was found that the verification of the product is reduced several times.
Corrosion resistance of plasma transferred arc (PTA) Inconel 625 deposits
Authors: Garcia Regina Paula , Luz Temístocles , Canobre Sheila Cristina , Costa Henara Lillian 
Published: March 2021

Abstract
Although the industrial sector is very restrictive in terms of the amount of dilution of the substrate allowed in welded Inconel coatings (often below 10%), the real impact of small changes in dilution on corrosion resistance of Inconel deposits is not clear yet. To evaluate this, welding current, welding speed and powder feed rate were varied within narrow ranges during PTA deposition of Inconel 625 onto carbon steel substrates. The effects of welding parameters on dilution and convexity index of the beads were analyzed within the established operational envelope. Potentiodynamic corrosion tests were carried out using solutions with different corrosion aggressiveness for specimens with different dilutions. The current of 180 A appeared as a transient point for the effects of the welding current on dilution and convexity index, suggesting a complex interaction between welding current, welding speed and powder feed rate. XRD results showed that for the specimens with higher dilution, only the region very close to the interface with the substrate was affected, suppressing the formation of the M2C. Interdendritic corrosion with preferential dissolution of some phases was observed as the main corrosion mechanism for all the deposits. The specimens with higher dilution showed tendency for secondary passivation in NaCl and NaCl + FeCl3 solutions. Moreover, the corrosion potential and corrosion current density values obtained for the specimens with lower and higher dilution were very close, with negligible differences, regardless of the position in the bead. The presence of FeCl3 in the electrolyte shifted the corrosion potential to more positive values. In the NaCl + H2SO4 solution, the deposits showed significant differences only in terms of passivation current between higher and lower dilution specimens. However, in general the differences between the deposits were negligible, showing good overall aqueous corrosion resistance in a wide range of highly aggressive environments. Therefore, this work found a relatively wide operational envelope for Inconel 625 PTA deposits, showing that small changes in deposition conditions, and thus in dilution, do not affect the coating applicability.
Atomic configuration controlled photocurrent in van der Waals homostructures
Authors: Xiong Ying , Shi Li-kun , Song Justin C W 
Published: March 2021

Abstract
Conventional photocurrents at a p–n junction depend on macroscopic built-in fields and are typically insensitive to the microscopic details of a crystal’s atomic configuration. Here we demonstrate how atomic configuration can control photocurrent in van der Waals (vdW) materials. In particular, we find bulk shift photocurrents (SPCs) can display a rich (atomic) configuration dependent phenomenology that range from contrasting SPC currents for different stacking arrangements in a vdW homostructure (e.g. AB vs BA stacking) to a strong light polarization dependence for SPC that align with crystallographic axes. Strikingly, we find that SPC in vdW homostructures can be directed by modest strain, yielding sizeable photocurrent magnitudes under unpolarized light irradiation and manifesting even in the absence of p–n junctions. These demonstrate that SPC are intimately linked to how the Bloch wavefunctions are embedded in real space, and enables a new macroscopic transport probe (photocurrent) of lattice-scale registration in vdW materials.
Microstructure evolution and coarsening kinetics of semisolid CuSn10P1 alloy under short-time isothermal treatment
Authors: Li Yongkun , Yu Xiangyang , Zhou Rongfeng , Li Lu , Zhang Yuanbo , Xiao Han 
Published: March 2021

AbstractThe key success of semisolid rheology is to prepare high-quality semisolid slurries. To achieve that it is necessary to be able to characterize the microstructure, element distribution, and coarsening mechanism during short-time isothermal treatment. This present work applied the enclosed cooling slope channel (ECSC) to make a semisolid slurry of CuSn10P1 alloy. Effects of short-time isothermal treatment (0, 5, 10, 15, 20, 25 s) on microstructure characteristics, element distribution, grain stability, and coarsening kinetics of semisolid CuSn10P1 alloy were studied. The equiaxed or near-globular microstructure can be prepared and improved intergranular segregation of CuSn10P1 alloy through the semisolid slurry short-time isothermal treatment. The mean diameter of primaryα-Cu phase gradually increases with soaking time prolonged, but shape factor shows a wavy trend. The mean size and shape factor changes caused by the instability of primaryα-Cu phase during short-time isothermal treatment can be described by the melting mechanism and the coarsening mechanism. The relationship between the high Tin layer thickness of primaryα-Cu and soaking time is consistent with the linear equation. The relationships of the Sn mass fraction in intergranular microstructure and primaryα-Cu phase center versus soaking time are consistent with an exponential equation. The suitable isothermal treatment parameters for the semisolid CuSn10P1 alloy is the soaking time 15 s to 20 s at 990 °C.
High temperature oxidation behavior and mechanism of FeXCr0.5Ti ferritic stainless steels
Authors: Jiang Xueyu , Che Xin , Zhang Zhipeng , Yin Shuying , Wang Hailong , Chen Lijia 
Published: March 2021

Abstract
In order to investigate the oxidation mechanism of ferritic stainless steel during long-term oxidation at high temperature. The oxidation behavior of Fe-Cr-Ti ferritic stainless steels with 10.38 wt% Cr and 17.41 wt% Cr at 800 °C and 900 °C for 100 h was studied by a constant temperature weight gain method. The morphology and composition of the oxide film were characterized by SEM, EDS and XRD. The experimental results indicate that the oxygen element mainly diffuses inward at 800 °C for two stainless steels, and the oxide film is composed of (Cr1.3Fe0.7)O3 + MnCr2O4. When the temperature rises to 900 °C, metal element mainly diffuses outward, and Fe2O3 outer oxide layer and Fe rich Fe-Cr inner oxide layer are formed in Fe11Cr0.5Ti stainless steel; Cr2O3 + Cr rich M3O4 spinel oxide film is formed in Fe18Cr0.5Ti stainless steel, while the inner layer is composed of SiO2. The main reason for the significant decrease of oxidation resistance of Fe11Cr0.5Ti stainless steel is that the low content of Cr cannot form a Cr rich oxide layer to inhibit the outward diffusion of Fe element, and the stability of oxide film is poor to protect the matrix.
Research progress of surface-modified graphene-based materials for tribological applications
Authors: Wang Mingyue , Zhou Ming , Li Xiao , Luo Chaogui , You Shengli , Chen Xin , Mo Youtang , Zhu Hongwei 
Published: March 2021

Abstract
Graphene’s many excellent properties have cemented it as an essential research topic in materials science and beyond. It is widely used in photoelectric materials, sensors, battery electrode materials, composites, and so on. Graphene has attracted particular attention in the field of tribology. However, graphene agglomerates easily, limiting its performance when used directly. Therefore, considerable research has focused on methods of modifying the surface of graphene to improve its tribological performance, by improving the dispersion stability, friction reduction, wear resistance, or a combination of these. This paper focuses on the research progress of surface modification of graphene-based materials for tribological applications. According to the reaction principles, surface modification methods can be divided into covalent surface modification, noncovalent surface modification, and surface modification by nanoparticles doping. Herein, the typical reaction processes of these modification methods and the anti-wear mechanism of modified graphene-based materials are introduced, and current research on the surface modification of graphene used in tribology is discussed.
The preparation and properties of polyurethane foams reinforced with bamboo fiber sources in China
Authors: Qiu Chongpeng , Li Feng , Wang Liang , Zhang Xuelun , Zhang You , Tang Qi , Zhao Xiyu , De Hoop Cornelis F , Peng Xiaopeng , Yu Xiaojuan , Huang Xingyan 
Published: March 2021

Abstract
Polyurethane (PU) foams reinforced with bamboo fiber sources in China, i.e., bamboo fiber, bamboo α-cellulose fiber, and bamboo nanocellulose fiber, were prepared and their physico-mechanical properties were analyzed in this work. The bamboo fiber sources and PU foams were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), Thermal gravimetric analysis (TGA) and universal compression testing. The results indicated that the hydroxyl groups on the fiber surfaces were enhanced by removing non-celluloses in the preparation of α-cellulose and nanocellulose. With the addition of small particle size α-cellulose and nanocellulose, the cell sizes of PU foams were reduced due to more nucleating agents being introduced. The FTIR spectra confirmed that the bamboo fiber sources were involved in the foaming reaction. The PU foams with bamboo fiber sources had a higher thermal stability than neat foam, and they were satisfactory enough to be used as insulation. PU foams reinforced with 5% bamboo fiber, 3% α-cellulose fiber and 3% nanocellulose fiber had better physico-mechanical performance than other foams. The reinforcement performance of 3% bamboo α-cellulose fiber on PU foam was comparable with that of high-cost nanocellulose. Accordingly, bamboo α-cellulose fiber was demonstrated to be a promising candidate to reinforce PU foam, which could be used in the reinforcement of foam insulation.
Laser-induced breakdown spectroscopy for the classification of wood materials using machine learning methods combined with feature selection
Authors: CUI Xutai , WANG Qianqian , WEI Kai , TENG Geer , XU Xiangjun 
Published: March 2021

Abstract
In this paper, we explore whether a feature selection method can improve model performance by using some classical machine learning models, artificial neural network, k-nearest neighbor, partial least squares-discrimination analysis, random forest, and support vector machine (SVM), combined with the feature selection methods, distance correlation coefficient (DCC), important weight of linear discriminant analysis (IW-LDA), and Relief-F algorithms, to discriminate eight species of wood (African rosewood, Brazilian bubinga, elm, larch, Myanmar padauk, Pterocarpus erinaceus, poplar, and sycamore) based on the laser-induced breakdown spectroscopy (LIBS) technique. The spectral data are normalized by the maximum of line intensity and principal component analysis is applied to the exploratory data analysis. The feature spectral lines are selected out based on the important weight assessed by DCC, IW-LDA, and Relief-F. All models are built by using the different number of feature lines (sorted by their important weight) as input. The relationship between the number of feature lines and the correct classification rate (CCR) of the model is analyzed. The CCRs of all models are improved by using a suitable feature selection. The highest CCR achieves (98.55...0.39)% when the SVM model is established from 86 feature lines selected by the IW-LDA method. The result demonstrates that a suitable feature selection method can improve model recognition ability and reduce modeling time in the application of wood materials classification using LIBS.
Roll-to-roll fabrication of highly transparent Ca:Ag top-electrode towards flexible large-area OLED lighting application
Authors: Wang Dongxiang , Hauptmann Jacqueline , May Christian , Hofstetter Yvonne J , Vaynzof Yana , Müller Tobias 
Published: March 2021

Abstract
Transparency and bendability are some of the most attractive unique selling points for organic light-emitting diode (OLED) lighting, enabling a variety of new application possibilities for industrial and private end-users. The roll-to-roll (R2R) OLED fabrication based on thermal evaporation offers a fast, continuous-running solution for producing flexible OLEDs at a lower cost. In this work, R2R fabricated large-area highly transparent thermal co-evaporated Ca:Ag (2:1 vol.%) top-electrode with mean transmittance of 64% over the visible range and a corresponding sheet resistance of as low as 21 Ω sq−1 was achieved. By increasing the film thickness to 24 nm, the sheet resistance can be further reduced to 12 Ω sq−1, albeit with a lower mean transmittance of 58%. The Ca:Ag electrode demonstrates a high mechanical durability through 1000 bending cycles, which is highly desirable as a characteristic for flexible electronics, as well as for the R2R fabrication. Finally, the stability of the Ca:Ag electrode in vacuum and ambient was studied as well.