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1
Diaz, Julio Cesar, Kurtis Watanabe, Aldo Rubio, et al. "Effect of Layer Thickness and Heat Treatment on Microstructure and Mechanical Properties of Alloy 625 Manufactured by Electron Beam Powder Bed Fusion." Materials 15, no. 21 (2022): 7767. http://dx.doi.org/10.3390/ma15217767.
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This research program investigated the effects of layer thickness (50 µm and 100 µm) on the microstructure and mechanical properties of electron beam powder bed fusion (EBPBF) additive manufacturing of Inconel 625 alloy. The as-built 50 µm and 100 µm layer thickness components were also heat treated at temperatures above 1100 °C which produced a recrystallized grain structure containing annealing twins in the 50 µm layer thickness components, and a duplex grain structure consisting of islands of very small equiaxed grains dispersed in a recrystallized, large-grain structure containing annealing twins. The heat-treated components of the microstructures and mechanical properties were compared with the as-built components in both the build direction (vertical) and perpendicular (horizontal) to the build direction. Vickers microindentation hardness (HV) values for the vertical and horizontal geometries averaged 227 and 220 for the as-built 50 µm and 100 µm layer components, respectively, and 185 and 282 for the corresponding heat-treated components. The yield stress values were 387 MPa and 365 MPa for the as-built horizontal and vertical 50 µm layer geometries, and 330 MPa and 340 MPa for the as-built 100 µm layer components. For the heat-treated 50 µm components, the yield stress values were 340 and 321 MPa for the horizontal and vertical geometries, and 581 and 489 MPa for the 100 µm layer components, respectively. The elongation for the 100 µm layer as-built horizontal components was 28% in contrast with 65% for the corresponding 100 µm heat-treated layer components, an increase of 132% for the duplex grain structure.
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Pan, Yuxin, Ming Yu, Chao Xu, Jianchao Zhang, and Lin Geng. "High-Performance 2319 Aluminum Alloy via CMT-WAAM: Microstructure, Porosity, and Mechanical Properties." Metals 14, no. 7 (2024): 797. http://dx.doi.org/10.3390/met14070797.
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The process of cold metal transfer (CMT) wire arc additive manufacturing (WAAM) for 2319 aluminum alloy was studied. The research investigated the coarse and fine equiaxed grain bands and porosity of the 2319 alloy after solution aging treatment, with a focus on the mechanical properties and deformation behavior of the aluminum alloy at different positions and orientations. Pores and coarse second phases mainly appeared at grain boundaries but were also observed within coarse equiaxed grains. The yield strength of the top horizontal samples reached 325.5 MPa, one of the highest yield strengths reported for 2319 aluminum alloy in the literature. The coarse brittle second phases at grain boundaries were the main crack sources during the failure process of the samples. In the fine equiaxed grain layer, cracks propagated along the grain boundaries connected to the second phases, and the presence of pores accelerated crack propagation; in the coarse equiaxed grain layer, cracks directly penetrated through the grains.
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Tang, Yang Jie, Yong Zhong Zhang, Yan Tao Liu, and Wei Pan. "Characteristics and Evolution Mechanism of Solidification Microstructure for Laser Additive Manufactured Ti2AlNb-Based Alloy." Materials Science Forum 913 (February 2018): 118–25. http://dx.doi.org/10.4028/www.scientific.net/msf.913.118.
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Laser additive manufacturing (LAM) technology was applied to prepare Ti-22Al-25Nb alloy thin-wall sample. The characteristics and evolution mechanism of solidification microstructure were investigated, and the tensile properties at horizontal and vertical directions were discussed. The results indicated that the solidification microstructure in single deposition layer evolved as: plane crystal structure, cellular crystal structure, columnar dendrite structure and equiaxed dendrite structure, from the bottom to the top of the molten pool. During the solidification process, the temperature gradient and solidification velocity decided the grain growth morphology. However, the grain of the as-deposited materials grew up to thick equaxied structure when the upper layer was forming. The tensile properties at horizontal and vertical directions were not much different, both of these exhibited high strength and low ductility.
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Abu-Safe, Husam. "TEM Investigation of Horizontal-Grown Silicon Nanowires." Advanced Materials Research 324 (August 2011): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amr.324.201.
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Horizontal silicon nanowires were grown using thermal annealing of thin layers of aluminum on silicon substrates. The template to grow these wires was the thin aluminum layer. As the samples reached the eutectic temperature during annealing, silicon dissolved rapidly in the aluminum layer and deposited at the grain boundary in a form of silicon nanowires. Cross sectional TEM analysis indicated the crystalline structure of these wires.
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Bao, Yubo, Hongwei Sun, Xiaoyu Cai, Sanbao Lin, and Chao Chen. "Effect of External Magnetic Field on the Forming, Microstructure and Property of TC4 Titanium Alloy during the Directed Energy Deposition Arc Additive Manufacturing." Crystals 13, no. 2 (2023): 235. http://dx.doi.org/10.3390/cryst13020235.
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In this work, the thin wall components of TC4 titanium alloy were produced by using external magnetic field hybrid gas metal welding (EM-GMAW). The effect of the external magnetic field on the forming, microstructure, and property of wire arc additively manufactured TC4 titanium alloy was studied in detail. The results showed that the height of the average deposition layer of EM-GMAW was less than that of GMAW and decreased with the increase of magnetic excitation current, and the width of the average deposition layer of EM-GMAW was greater than that of GMAW. The microstructure of the deposition layer consisted of fine α phase and coarse β grains. Compared with the traditional GMAW, the coarse β grain size in the EM-GMAW was reduced obviously. The maximum size of β grain was decreased by 100μm when the magnetic excitation current of 3A was used. In addition, the EM-GMAW tensile strength in the transverse and horizontal was increased by around 20 MPa and 100 MPa, respectively, compared with that of GMAW.
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Kotov, B., and S. Stepanenko. "Analysis of the influence of non-uniformity of air flow velocity on the trajectory of grain particles motion in a pneumatic inertial separator." Mehanization and electrification of agricultural, no. 10(109) (2019): 66–77. http://dx.doi.org/10.37204/0131-2189-2019-10-6.
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Purpose. Determination of influence of non-uniform velocity field of air in horizontal channel of pneumatic inertial separator on efficiency of separation of components of grain material into fractions by aerodynamic properties. Methods. The specificity of the issue under consideration determines the analytical method of study based on the compilation and analysis of kinetic equations of motion of a particle, in the form of a ball in the air flow of a horizontal channel with uneven distribution of air flow velocity over the height of the pneumatic channel. Results. The mathematical description of the motion of particles of the grain mixture in the chamber of the gravitational-air separator under the action of air flow of variable speed air is given. The trajectories of motion of particles of different size were obtained. The obtained equation of motion of a particle under the action of air flow allows to determine the dependence of the speed of movement of the material in the layer of grain material on a number of factors: geometric parameters of the separator, the angle of feed of the material, the initial kinematic mode of the material, as well as the coefficient of sail of the particle. The technological possibilities of the proposed method of grain separation under the action of air flow are theoretically substantiated and the influence on the technological parameters of the basic parameters: air velocity, coefficient of live section taking into account the layer thickness of the material entering the channel is established. Conclusions 1.On the basis of the analysis of the force interaction of the grain material particle with the air stream, an advanced mathematical model of particle motion in a non-uniform field of air flow velocity in the horizontal channel was obtained. 2.The real possibility of controlling the process of separation of components of grain material by aerodynamic properties by changing the plot of the air flow velocity along the height of the horizontal channel is determined. Keywords: variable air velocity, trajectory, resistance of forces, fractions, air flow, wind factor, fractionation process, grain mixture, air separator.
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Vasiliev, A. M., S. A. Machikhin, A. N. Strelyukhina, and A. A. Ryndin. "Influence of geometry of corrugated base surface of working bodies on the sorting of grain mixes." Proceedings of the Voronezh State University of Engineering Technologies 80, no. 3 (2018): 26–30. http://dx.doi.org/10.20914/2310-1202-2018-3-26-30.
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The article is devoted to the substantiation of the creation of new bearing surfaces of the working bodies of vibration separating machines, the use of which contributes to an increase in the intensity of one of the stages of the separation processes - self-sorting. When studying the influence of one or another factor on the efficiency of self-sorting, experiments were carried out with the same grain mixture on the working surfaces bounded on four sides by the walls with horizontal harmonic oscillations of the horizontal working surfaces. The most common light particle was used as a model particle. an impurity in the wheat grain is a straw. Experiments are devoted to determining the time of the emergence of a light particle in a layer of wheat grain. Experiments were carried out on the working surface with grooves forming zigzag channels, grooves of variable height, with the arrangement of the flute perpendicular to the direction of oscillation of the working member and with the arrangement of the flute at an angle to the direction of oscillation. In the experiments, the thickness of the grain flow layer above the grooves and the position of the light particle in the layer relative to the supporting surface were varied, so that the time when the light particle emerges through the layer of the same thickness but located at different distances from the flute of the supporting surface. This made it possible to eliminate the influence of the layer thickness on the time (speed) of the ascent of the light particle and to estimate the effect on the self-sorting intensity (the ascent time) only on the flute of the support surface. It has been experimentally proved that an increase in the efficiency of the self-sorting process on the working surface can be achieved by installing a flute perpendicular to the direction of oscillation.
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Pawar, Ashish, and Vaibhav Singh. "Geotechnical Site Characterization-A Review." Journal of Geotechnical Studies 7, no. 2 (2022): 1–4. http://dx.doi.org/10.46610/jogs.2022.v07i02.001.
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Geotechnical characterization of soil helps in determine and interpret soil behaviour in a specific location, and determine soil properties such as moisture content, specific gravity, plasticity, grain size analysis, strength properties, compressibility, and bearing capacity. The nature of geological formation is complex. The soil characteristics vary significantly with depth and horizontally at a particular site, as is commonly observed. Appropriate identification of different layers of soil, horizontal variations in layer depth and thickness, assessment of soil type and numerous technical qualities, and their variability within each layer are all critical. The soil testing process benefits the project's decision-making and cost-estimating stages. In this paper, a review has been presented regarding different geotechnical site characterizations conducted worldwide for various civil engineering projects were investigated.
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Gunawan, Sumiyati, Vienti Hadsari, Hadiatma Ananda, and Mellisa Nagata Christina. "Fine Content’s Impact on Liquefaction-Induced Volumetric Deformation." IOP Conference Series: Earth and Environmental Science 1488, no. 1 (2025): 012055. https://doi.org/10.1088/1755-1315/1488/1/012055.
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Abstract Babarsari, Sleman, D.I. Yogyakarta has unique soil characteristics, characterized by a thick sand layer, high water table, and fine grain/silt content that varies widely from 0.25% to 85%. Variation on the fines content controls Standard Penetration Test (SPT) value and post-liquefaction deformation. This study analyse the effect of fines content on SPT value, Cyclic Resistant Ratio (CRR), and Cyclic Stress Ratio (CSR). In addition, this paper analyses the effect of fines on horizontal and vertical displacement post-liquefaction. Idriss & Boulanger method is adopted to calculate CRR and CSR, while BartlettYoud method is used to calculate the post-liquefaction horizontal and vertical displacement due to the variation of fines content in sand layer. The results show that at the same NSPT value, sand with little fines has lower liquefaction resistance than sand with high percentage of fines. Liquefaction resistance, described through (N 1)60,cs , starts to increase to about 15% as the fine grain content increases, until it reaches the maximum value at 35%. Horizontal and lateral displacement decreases as the amount of fines increases. These findings provide important insights for prediction of liquefaction resistance, especially for local area, and estimation of post-liquefaction ground deformation, planning and design of safer infrastructure in earthquake-prone areas such as Yogyakarta.
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Mróz, Sebastian, Karina Jagielska-Wiaderek, Piotr Szota, Andrzej Stefanik, Robert Kosturek, and Marcin Wachowski. "Effect of the Shape of Rolling Passes and the Temperature on the Corrosion Protection of the Mg/Al Bimetallic Bars." Materials 14, no. 22 (2021): 6926. http://dx.doi.org/10.3390/ma14226926.
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The paper presents the results of experimental tests of the rolling process of Mg/Al bimetallic bars in two systems of classic passes (horizontal oval-circle-horizontal oval-circle variant I) and modified (multi-radial horizontal oval-multi-radial vertical oval-multi-radial horizontal oval-circle-variant II). The feedstock in the form of round bimetallic bars with a diameter of 22 mm and 30% of the outer aluminum layer was made through explosive welding. The bimetallic bars consisted of an AZ31 magnesium core and a 1050A aluminum outer layer. Bars with a diameter of 17 mm were obtained as a result of rolling in four passes. The rolling process in the passes was conducted at two temperatures of 300 and 400 °C. Based on the analysis of the test results, it was found that the use of modified passes and a lower rolling temperature (300 °C) ensures a more homogenous distribution of the plating layer around the circumference of the core and results in an even grain decreasing, which improves the corrosion resistance of bimetallic bars compared to rolling bars in a classic system of passes and at a higher temperature (400 °C).
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Loose, V. V., K. B. Gurieva, S. L. Beletsky, and T. G. Kostromina. "Temperature change of the wall layers of wheat grain during its storage in silos of elevators." Khleboproducty 31, no. 5 (2022): 50–59. http://dx.doi.org/10.32462/0235-2508-2022-31-5-50-59.
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Conducting research to clarify the mechanism of temperature migration inside reinforced concrete silos is relevant, since there is little data in the literature on the study of the dynamics of changes in internal temperatures in reinforced concrete silos, more over, they were obtained quite a long time ago. The purpose of experimental research is to study the dynamics of grain temperature change in the center of the silo in the traditional way using thermal suspensions, as well as a long horizontal layers, to determine the thickness of the near wall grain layer subject to the greatest heating / cooling, as well as to highlight the critical layer in it. The article presents an analysis of the results of monitoring the temperature regime of wheat storage using a measuring system of thermohygrometers (loggers) of the DS1923-F5 type. The studies were carried out during the annual cycle in the outer silos of an elevator located in the temperate climate of the West Siberian climatic region. The distribution of temperatures along the vertical of silos at three levels (upper, middle and lower), the distribution of temperatures along the horizontal of silos (at different distances from the wall of the silo from 5 to 75 cm) was studied. A comparative analysis of the data on the temperature regime in silos located on the southern and northern sides of the elevator was made. New original data from thermohygrometers were obtained, which were statistically processed. The thickness of the near wall layer of the grain mass, which is most susceptible to undesirable temperature effects for the outer silos of the southern and northern sides of the elevator, has been determined. near-wall layers of grain and spaced from the outer wall up to one meter. It is shown that the most critical with a higher temperature is the upper level, where it is necessary to more carefully control the quality of the grain. The middle and lower levels are in more favorable temperature conditions of preservation. The most critical horizontal layers of grain (i. e., having a temperature above 15 ° C in summer) at the lower level are the layers from the near-wall to the silo separated from the walls by 35 cm, and at the upper level all layers from the near-wall to the silo separated from the walls at 75 cm.
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Stepanenko, S. P., B. І. Kotov, and I. S. Popadyuk. "Investigation of the process of pneumatic vibration separation of grain by density during one-dimensional movement of grain flow." Mehanization and electrification of agricultural, no. 14(113) (2021): 77–87. http://dx.doi.org/10.37204/0131-2189-2021-14-8.
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Annotation Purpose. Formation of a mathematical description of the process of moving grains with different density in vibro-pneumatic liquefied grain medium under the action of pulsating air flow to determine the parameters of movement and the possibility of their separation into fractions. Methods. Theoretical determination of the dependences of the motion of grains with different densities in a vibro-pneumatic grain medium with pulsating air flow determines the mathematical method of research based on the addition and numerical solution of the equations of grain motion in a pneumatic vibrating separator. The mathematical model is formed as a result of drawing up the scheme of force interaction on grain in the vibro-pneumatic liquefied grain environment and the differential equations of movement of grains which are presented by a material point and indicators characterizing physical and mechanical properties of grain environment are received. Results. The motion of the center of mass of grains is considered as the motion of a certain particle, the coordinates of which coincide with the coordinates of the moving coordinate system (x, y), and the mass of a single grain m differs from the grains of the medium in density. The change of air flow velocity and the influence of pulsating air flow on the flow of grain material moving on a vibrating perforated surface are determined. The discrete-periodic change of the flow velocity, which is fed through the perforated support surface into the layer of grain material, is analytically described. The parameters of the grain motion process in an oscillating fluidized medium are determined, which are determined by the solution of a complex system of differential equations using computational methods using a PC. Conclusions. As a result of theoretical research, the possibility of increasing the efficiency of separation of grain materials by specific gravity of grains, by intensifying the process of separation of grain material provided the use of pulsating air flows to separate mixtures on vibrating surfaces and compared with existing separators using horizontal and inclined decks grain separation efficiency material increases by 35–42%. Keywords: pulsating air flow, grain, density, trajectory, fluidized medium, separation process, harmonic law of motion.
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Kalashnikova, Tatiana, Andrey Chumaevskii, Kirill Kalashnikov, et al. "Regularities of Friction Stir Processing Hardening of Aluminum Alloy Products Made by Wire-Feed Electron Beam Additive Manufacturing." Metals 12, no. 2 (2022): 183. http://dx.doi.org/10.3390/met12020183.
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Friction stir processing of additive workpieces in the sample growth direction (the vertical direction) and the layer deposition direction (the horizontal one) was carried out. The hardening regularities of aluminum-silicon alloy A04130 and aluminum-magnesium alloy AA5056 manufactured by electron beam additive technology were studied. For each material, 1 to 4 subsequent tool passes were performed in both cases. It was found that the formation of the stir zone macro-structure does not significantly change with the processing direction relative to the layer deposition direction in additive manufacturing. The average grain size in the stir zone after the fourth pass for AA5056 alloy in the horizontal direction was 2.5 ± 0.8 μm, for the vertical one, 1.6 ± 0.5 μm. While for the alloy A04130, the grain size was 2.6 ± 1.0 μm and 1.8 ± 0.7 for the horizontal and vertical directions, respectively. The fine-grained metal of the stir zone for each alloy in different directions had higher microhardness values than the base metal. The tensile strength of the processed metal was significantly higher than that of the additively manufactured material of the corresponding alloy. The number of tool passes along the processing line is different for the two selected alloys. The second, third and fourth passes have the most significant effect on the mechanical properties of the aluminum-magnesium alloy.
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Alexander, Nanka, Iyevlev Ivan, Sementsov Vitaliy, Boiko Denis, and Duhanets Viktor. "CONSTRUCTION OF MATHEMATICAL MODELS OF THE STATICS OF GRAIN MEDIA CONSIDERING THE REYNOLDS EFFECT." Eastern-European Journal of Enterprise Technologies 6, no. 7 (102) (2019): 53–62. https://doi.org/10.15587/1729-4061.2019.184592.
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This study addresses the construction of a mathematical model, the statement of boundary-value problems on the statics of a grainy material related to the technological processes of agricultural production. A working apparatus employed to construct the model of a grainy material is the methods of equilibrium thermodynamics. We have stated the main thermodynamic equality, which makes it possible to derive a rheological ratio that establishes the connection between stresses and deformations of the granular material. The chosen grainy material is a granular medium that manifests a Reynolds effect. This effect occurs in the case of small deformations and indicates the presence of a dependence of dilation on the stress tensor deviator. In contrast to the classical methods that consider a model of continuous medium with the non-deformed and smooth grain’s particles, the present work takes into consideration both a Reynolds effect and the presence of elastic deformations. The resulting rheological ratio produces the dependence for a stress tensor on the deformation tensor corresponding to ratios from the linear theory of elasticity. For the case of an isothermal process of deformation, a boundary-value problem on the grain material’s statics in the field of gravity has been stated. This paper shows the statement and solution to two particular tasks on the balance of a granular layer along the horizontal plane: in the absence of surface forces and under the action of tangent surface forces on a free surface. The boundary problems on the equilibrium of a granular material are nonlinear in character, and the resulting solution represents a complex mathematical apparatus involving numerical methods. The obtained models for the statics of a continuous environment precede the consideration of dynamic problems, in particular, the study of equilibrium stability
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Gurieva, К. B., V. V. Looze, and S. L. Beletskiy. "The study of the distribution of temperature fields of wheat grain along the vertical levels and horizontal layers during storage in the elevator silo." Tovaroved prodovolstvennykh tovarov (Commodity specialist of food products), no. 8 (July 24, 2023): 476–87. http://dx.doi.org/10.33920/igt-01-2308-05.
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This article presents an analysis of the temperature fi elds caused by seasonal fluctuations in the temperature of the outside air on the surface of the walls of the silos and inside the outdoor silo located on the south side of the precast concrete elevator for the annual cycle from March 2018 to March 2019. The paper analyzes the data of grain temperature along the horizontal layers of the silo at the upper and lower levels and the distribution of temperature fields over the upper and lower levels of the silo during heating and cooling of the grain. A comparative analysis of the heating and cooling rates and the effect of temperature differences in the silo on moisture absorption processes in the grain mass during storage is carried out. During the statistical processing of the experimental data, the following trends were obtained: in the deep layers of the grain, when the grain is heated, the temperature is lower, and when the grain is cooled, the temperature is higher than in the nearwall layers. The rate of temperature change in the grain mass depends on the location of the grain at different levels and on the horizontal layer. The average cooling rates were lower than the grain heating rates, and during the annual cycle, heat accumulation in the grain mass stored in the silo is possible. The infl uence of thermal moisture conductivity on the change in the humidity regime in the silo is considered. The results for the annual cycle indicate a cyclical change in the relative humidity of the intergranular space and an increase in the relative humidity in the summer-autumn period (from May to November) above the optimal value recommended for long-term storage. To eliminate the risks of grain moisture, the need for periodic movement of grain from silo to silo during long-term storage is substantiated.
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Machyhin, S. A., A. A. Ryndin, A. M. Vasiliev, and A. N. Streljuhina. "Movement of the top layer of the grain mixture on the vibrating grooved surface." Proceedings of the Voronezh State University of Engineering Technologies 80, no. 4 (2019): 55–62. http://dx.doi.org/10.20914/2310-1202-2018-4-55-62.
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The most unfavourable conditions for the implementation of separation arise in the case where the impurities and clean the grain evenly distributed. Therefore, a layer of granular grain mixture should be pre-prepared for participation in the process, which can be estimated by analyzing the kinematic parameters of the movement of grain particles, which is the purpose of this study. The description of the working body and the process of vibration movement of the grain mixture is given. To describe the vibrational movement of the grain mixture, a two-layer model is considered, in which changes are made due to the presence of riffles in the form of rectilinear plates on the support surface. In the study of the movement of the upper layer of the grain flow, we consider the movement of a material point on an inclined plane that makes horizontal harmonic oscillations perpendicular to the line of the greatest slope. Consideration of the scheme of forces acting on the particle in relative motion and the conditions of motion of the particle, made it possible to write the differential equation of relative motion in the projections on the coordinate axis. The transformations of the obtained dependences allowed us to determine the minimum force of inertia at which the relative motion will begin. By introducing the concepts and designations of the phase angles at which the relative sliding of a particle begins and ends, we determined the type of dependence of the particle velocity upon its sliding. The dependences of the particle movement in the positive and negative directions of the x and y axes, the dependence of the total displacements along the axes, as well as the average particle velocity along the x axis were obtained.the model of the two-layer vibrational movement of the grain flow along the surface with the riffles in the form of rectangular plates at their arrangement perpendicular to the direction of oscillations was Considered.
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Ozherelev, Viktor N. "Grain heap separation at the grates of a combine feederhouse." Agricultural Engineering, no. 3 (2023): 35–40. http://dx.doi.org/10.26897/2687-1149-2023-3-35-40.
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Using the grates of a combine feederhouse and directing the grain heap for cleaning, bypassing the threshing unit, we can reduce both the energy intensity of harvesting and the degree of grain crushing. The study purpose is to compare two variants of the combine feederhouse grates: with longitudinal holes of a finite length and transverse bars between them and with through holes without transverse bars. For a preliminary assessment, a theoretical model of the separation process is proposed, which includes the slipping of combed heap layers moved by a conveyor scraper into the hole at the angle of repose. Previously, it was assumed that upon contacting with a transverse bar, the corresponding heap layer completely stops slipping and the process resumes only after overcoming the edge of the next hole. As a result, the separation rate should significantly decrease. The upgraded version of the model takes into account the inertia effect on the sliding upper heap layer, which is activated by the friction force of its lower part acting along the bar surface. As a result of the total effect of the rolling force and the inertia force, the flow direction of the upper layer components changes to become nearly horizontal, as a result of which 50 to 60% of the layer slides into the next hole without stopping. According to the theoretical model, the separation of combed grain heap should be reduced by 4 to 5% if there are 120 mm long bars between the longitudinal holes and the total length of the separating part of the grates surface is 800 mm. As a result of a laboratory experiment on the Moskovskaya 56 wheat variety, the separation of a combed grain heap decreased by 4.6% due to transverse bars, which confirmed the adequacy of the theoretical hypothesis.
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Kupreenko, Aleksey, Khafiz Isaev, Yury Kuznetsov, Stanislav Mikhailichenko, Igor Kravchenko, and Larisa Kalashnikova. "The use of solar plants for crop seeds drying." Poljoprivredna tehnika 46, no. 4 (2021): 1–9. http://dx.doi.org/10.5937/poljteh2104001k.
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A grain drying complex based on solar energy, including a grain storage with a built-in solar drying system and a drum solar dryer for grain, is proposed. The construction and principle of operation of the grain drying complex is described. The basis of each of the solar drying systems of the complex is the presence of two solar collectors, one of which provides heating of the drying agent at the inlet into the drying chamber, and the second-heating of the used drying agent in the exhaust pipe to increase its flow rate and, accordingly, the intensification of grain drying. Availability of gravel or water heat accumulators allows to carry out the process of grain drying or grain storage, at night and under adverse weather conditions without the risk of self-heating. The optimum capacity of the gravel accumulator is 0.5-0.75 m 3 per 1 m 2 of solar collector area. Drum solar dryer provides guaranteed drying of a grain batch for 6-7 hours of the day time and a grain batch for the night time. It was found that the optimum thickness of the grain layer in the drying process is 50-70 cm and specific load is up to 100 kg of grain per square meter of the horizontal solar collector area.
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Grigorov, I. Yu, A. N. Grechukhin, and I. A. Chernyshev. "Investigation of the Microstructure and Elemental Composition of Samples Obtained by the Method of Layer-by-Layer Construction by an Electric Arc in a Protected Atmosphere." Proceedings of the Southwest State University 27, no. 2 (2023): 8–23. http://dx.doi.org/10.21869/2223-1560-2023-27-2-8-23.
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Purpose of research. The article is devoted to the metallographic study of the structure, as well as the elemental composition of the characteristic zones of samples obtained by the method of layer-by-layer construction of an electric arc in a protected atmosphere. The samples for the study were obtained using a mechatronic system with numerical control, which provides positioning of the device for feeding the filler material in the form of a wire along three coordinate axes. The samples were formed on a receiving surface made of steel 3, the material for layer–bylayer construction was alloy steel Sv–09G2S, the electric arc power source was an inverter-type welding machine Cedar MIG–160GDM, the protected atmosphere was a protective gas environment. The layered formation of experimental samples was implemented using the following schemes: in the horizontal plane; in the vertical plane. Preparation for metallographic examination was carried out in accordance with GOST 5639-82 "Steels and alloys. Methods of detection and determination of grain size", GOST R 57180-2016 "Welded joints. Methods for determining mechanical properties, macrostructure, microstructure". The elemental composition of the obtained samples was carried out by X-ray fluorescence analysis using the X-MET 5100 analyzer. As a result of the conducted studies, the presence of voids between single layers in the horizontal plane was revealed; the material of the receiving surface in the root passage zone and the zone of thermal influence have a structure with lower physical and mechanical properties, as well as lower corrosion resistance compared to the material of the receiving surface. The material of the samples formed in the vertical plane has a structure similar in grain size to the material of the receiving surfaceMethods. In the course of the work, methods of microstructure research, as well as elemental analysis were appliedResults. As a result of the work performed on this study, it was revealed that during the formation of single layers on the receiving surface in the horizontal plane, the formation of critical defects - voids and "non-vapors" takes place. The zone of thermal influence, the zone of the root passage contains a metal microstructure that has lower physical and mechanical characteristics and corrosion resistance compared to the material of the receiving surfaceConclusion. When forming products by the method of layer-by-layer construction of an electric arc in a protected atmosphere, the following technological features of the process must be taken into account: in order to prevent the formation of critical defects during layer-by-layer construction of layers in a horizontal plane, it is necessary to establish a range of values of the overlap coefficient of layers; in order to ensure the creation of homogeneous metal structures in the fusion zone of the receiving surface and the construction material, as well as to minimize the size of the zone of thermal influence and the root passage zone, it is necessary to build layers using the receiving surface of materials that maximally correspond in chemical composition to the construction material.
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Mazumder, B. S., and D. C. Dalal. "Saltation Layer of Particles in Water Flows Related to Transport Stage." Hydrology Research 34, no. 4 (2003): 343–60. http://dx.doi.org/10.2166/nh.2003.0011.
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A theoretical model has been developed to determine the maximum saltation layer thickness of sediment particles in water associated with the migration velocity of particle in the bed layer. This is consistent with Owen's (1964) hypothesis for saltation of uniform grain in air. The equation for mean particle velocity at the bed is derived by balancing the horizontal forces acting on the particle in the bed. The modified expression for mean particle velocity includes the effects of drag and lift coefficients, bed shear stress, coefficient of dynamic friction, settling velocity and pivoting angle. The saltation layer model presented here extends a reasonable physical assumption by converting the average horizontal particle velocity to a vertical component of velocity due to collisions with particles resting on the bed. This explicitly shows a functional dependence of saltation height on mean particle velocity and take-off angle. The proposed model has been tested using available experimental data and the agreement with particle velocities and saltation heights is excellent. An interesting outcome is that a quadratic relationship is suggested between the higher transport stage (upper plane bed) and the take-off angle of particle. This shows that the take-off angle decreases with increase in transport stage.
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Martínez-Segura, Marcos A., Carmelo Conesa-García, Pedro Pérez-Cutillas, Pedro Martínez-Pagán, and Marco D. Vásconez-Maza. "Identifying Changes in Sediment Texture along an Ephemeral Gravel-Bed Stream Using Electrical Resistivity Tomography 2D and 3D." Applied Sciences 11, no. 7 (2021): 3030. http://dx.doi.org/10.3390/app11073030.
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Differences in deposit geometry and texture with depth along ephemeral gravel-bed streams strongly reflect fluctuations in bedload which are due to environmental changes at the basin scale and to morphological channel adjustments. This study combines electrical resistivity tomography (ERT) with datasets from borehole logs to analyse the internal geometry of channel cross-sections in a gravel-bed ephemeral stream (southeast Spain). The survey was performed through longitudinal and transverse profiles in the upper channel stretch, of 14 to 30 m in length and 3 to 6 m in depth, approximately. ERT values were correlated with data on sediment texture as grain size distribution, effective grain sizes, sorting, and particle shape (Zingg’s classification). The alluvial channel-fills showed the superposition of four layers with uneven thickness and arrangement: (1) the softer rocky substrate (<1000 Ω.m); (2) a thicker intermediate layer (1000 to 2000 Ω.m); and (3) an upper set composed of coarse gravel and supported matrix, ranging above 2000 Ω.m, and a narrow subsurface layer, which is the most resistive (>5000 Ω.m), corresponding to the most recent armoured deposits (gravel and pebbles). The ERT results coupled with borehole data allowed for determining the horizontal and vertical behaviour of the materials in a 3D model, facilitating the layer identification.
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RUTTER, N., H. P. MARSHALL, K. TAPE, R. ESSERY, and J. KING. "Impact of spatial averaging on radar reflectivity at internal snowpack layer boundaries." Journal of Glaciology 62, no. 236 (2016): 1065–74. http://dx.doi.org/10.1017/jog.2016.99.
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ABSTRACTMicrowave radar amplitude within a snowpack can be strongly influenced by spatial variability of internal layer boundaries. We quantify the impact of spatial averaging of snow stratigraphy and physical snowpack properties on surface scattering from near-nadir frequency-modulated continuous-wave radar at 12–18 GHz. Relative permittivity, density, grain size and stratigraphic boundaries were measured in-situ at high resolution along the length of a 9 m snow trench. An optimal range of horizontal averaging (4–6 m) was identified to attribute variations in surface scattering at layer boundaries to dielectric contrasts estimated from centimetre-scale measurements of snowpack stratigraphy and bulk layer properties. Single vertical profiles of snowpack properties seldom captured the complex local variability influencing near-nadir radar surface scattering. We discuss implications of scaling in-situ measurements for snow radiative transfer modelling and evaluation of airborne microwave remote sensing of snow.
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Saitov, Viktor, Vyacheslav Farafonov, and Aleksey Saitov. "Influence of the angle of the bath bottom inclination in ergot isolation device on grain immersion in a liquid." E3S Web of Conferences 164 (2020): 06004. http://dx.doi.org/10.1051/e3sconf/202016406004.
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For the mechanization of the allocation of toxic ergot from the rye seeds in a wet way, the urgent issue is the development of a device containing a bath with an aqueous solution of salt. The aim of the study is to determine the influence of the angle of inclination of the bottom of the bath on the rate of immersion of grains in the fluid of the device for separating ergot from rye seeds, which will ensure the efficiency of the process. Theoretically, we consider the movement of individual rye grains along the inclined surface of the bottom of the bath of the ergot extraction device. Rye grains have a density ρz = (1.2...1.5)·103 kg/m3, a length lz = (5.0. 10.0)·10-3 m, a width b = (1.4...3.6)·10-3 m, and a thickness δ = (1.2 3.5)·10-3 m. Geometric models of these grains are presented in the form of cylindrical and spheroidal grains. The movement of grain on the surface of the bottom of the bath of an ergot extraction device is considered at angles of inclination α = 27, 30, 40, 50, 60, 70, 80, and 90 degrees by the methods of mathematical modeling, classical mechanics using the laws of hydrodynamics. It was established that the angle α of the slope of the surface of the bottom of the bathtub to the horizontal should be taken at least 650, at which accumulation is excluded due to the rapid rolling of the grain and a decrease in the thickness of its layer.
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Smirnov, V. I., and S. A. Vidyushenkov. "On some mechanical characteristics of the ballast in assessing the stress-strain behaviour of railway tracks." BRIСS Transport 2, no. 2 (2023): 1–7. http://dx.doi.org/10.46684/2023.2.3.
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On the basis of recent research, a review has been carried out on the experimental determination of the mechanical parameters of the materials used as ballast material. Considerable attention is given to the well-founded selection of input data for the calculation, i. e. quantitative characteristics of the elastic properties of the materials used to form the ballast layer, which is treated as a continuous medium. It appears that this approach makes it possible to assess correctly the influence of grain (grain size distribution) distribution, ballast layer thickness and material type on the stability of a railway track to vertical and horizontal disturbances. The data of this review show that material properties and particle size have a signifi cant impact on elastic moduli and in finite-element modelling of static strength problems, grain-size distribution and material properties are only taken into account through these moduli. Experimental results show a non-linear dependence of the elastic moduli on the stress behaviour of the ballast prism, which is related to a densifi cation of the medium in compression. However, it is established that, after a suffi ciently large number of loading cycles, the medium can be treated as linearly elastic. In general, the results of the research allow establishing requirements for damping, geometric and granulometric parameters of the ballast prism.
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WONGPAN, PAT, DAVID J. PRIOR, PATRICIA J. LANGHORNE, KATHERINE LILLY, and INGA J. SMITH. "Using electron backscatter diffraction to measure full crystallographic orientation in Antarctic land-fast sea ice." Journal of Glaciology 64, no. 247 (2018): 771–80. http://dx.doi.org/10.1017/jog.2018.67.
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ABSTRACTWe have mapped the full crystallographic orientation of sea ice using electron backscatter diffraction (EBSD). This is the first time EBSD has been used to study sea ice. Platelet ice is a feature of sea ice near ice shelves. Ice crystals accumulate as an unconsolidated sub-ice platelet layer beneath the columnar ice (CI), where they are subsumed by the advancing sea–ice interface to form incorporated platelet ice (PI). As is well known, in CI the crystal preferred orientation comprises dominantly horizontal c-axes, while PI has c-axes varying between horizontal and vertical. For the first time, this study shows the a-axes of CI and PI are not random. Misorientation analysis has been used to illuminate the possible drivers of these alignments. In CI the misorientation angle distribution from random pairs and neighbour pairs of grains are indistinguishable, indicating the distributions are a consequence of crystal preferred orientation. Geometric selection during growth will develop the a-axis alignment in CI if ice growth in water is fastest parallel to the a-axis, as has previously been hypothesised. In contrast, in PI random-pair and neighbour-pair misorientation distributions are significantly different, suggesting mechanical rotation of crystals at grain boundaries as the most likely explanation.
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BÖYÜK, U., K. YÜCEER, K. KEŞLIOĞLU, A. ULGEN, and N. MARAŞLI. "MEASUREMENTS OF SOLID–LIQUID INTERFACIAL ENERGIES IN THE ORGANIC MONOTECTIC ALLOYS." Surface Review and Letters 16, no. 02 (2009): 203–14. http://dx.doi.org/10.1142/s0218625x09012500.
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The commercial purity dibromobenzene (DBB) and succinonitrile (SCN) were purified using a columnar distillation system. Thin walled rectangular specimen cells (60–80 μm thick) were fabricated and filled with the purified materials under the vacuum. The specimen cell was placed in a horizontal temperature gradient stage. A thin liquid layer was melted and the specimen was annealed in a constant temperature gradient for an enough time to observe the equilibrated grain boundary groove shapes. The thermal conductivities of solid and liquid phases for the purified DBB and DBB–5.7 mol% SCN alloy were determined with the radial heat flow and the Bridgman-type growth apparatuses. From the observed grain boundary groove shapes, the Gibbs–Thomson coefficients, solid–liquid interfacial energies, and the grain boundary energies for solid DBB in equilibrium with its melts and solid DBB in equilibrium with DBB–SCN monotectic liquid have been determined. The temperature coefficients of the purified DBB and DBB–5.7 mol% SCN alloy were also determined from thermal conductivity curve vs temperature.
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Mazzuoli, Marco, Aman G. Kidanemariam, Paolo Blondeaux, Giovanna Vittori, and Markus Uhlmann. "On the formation of sediment chains in an oscillatory boundary layer." Journal of Fluid Mechanics 789 (January 22, 2016): 461–80. http://dx.doi.org/10.1017/jfm.2015.732.
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The dynamics of spherical particles resting on a horizontal wall and set into motion by an oscillatory flow is investigated by means of a fully coupled model. Both a smooth wall and a rough wall, the latter being composed of resting particles with a random arrangement and with the same diameter as the moving particles, are considered. The fluid and particle motions are determined by means of direct numerical simulations of Navier–Stokes equations and Newton’s laws, respectively. The immersed boundary approach is used to force the no-slip condition on the surface of the particles. In particular, the process of formation of transverse sediment chains, within the boundary layer but orthogonal to the direction of fluid oscillations, is simulated in parameter ranges matching those of laboratory experiments investigating rolling-grain ripple formation. The numerical results agree with the experimental observations and show that the transverse sediment chains are generated by steady recirculating cells, generated by the interaction of the fluid and particle oscillations.
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Avanzi, F., H. Hirashima, S. Yamaguchi, T. Katsushima, and C. De Michele. "Laboratory-based observations of capillary barriers and preferential flow in layered snow." Cryosphere Discussions 9, no. 6 (2015): 6627–59. http://dx.doi.org/10.5194/tcd-9-6627-2015.
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Abstract. Several evidences are nowadays available that show how the effects of capillary gradients and preferential flow on water transmission in snow may play a more important role than expected. To observe these processes and to contribute in their characterization, we performed observations on the development of capillary barriers and preferential flow patterns in layered snow during cold laboratory experiments. We considered three different layering (all characterized by a finer-over-coarser texture in grain size) and three different water input rates. Nine samples of layered snow were sieved in a cold laboratory, and subjected to a constant supply of dyed tracer. By means of visual inspection, horizontal sectioning and liquid water content measurements, the processes of ponding and preferential flow were characterized as a function of texture and water input rate. The dynamics of each sample were replicated using the multi-layer physically-based SNOWPACK model. Results show that capillary barriers and preferential flow are relevant processes ruling the speed of liquid water in stratified snow. Ponding is associated with peaks in LWC at the boundary between the two layers equal to ~ 33–36 vol. % when the upper layer is composed by fine snow (grain size smaller than 0.5 mm). The thickness of the ponding layer at the textural boundary is between 0 and 3 cm, depending on sample stratigraphy. Heterogeneity in water transmission increases with grain size, while we do not observe any clear dependency on water input rate. The extensive comparison between observed and simulated LWC profiles by SNOWPACK (using an approximation of Richards Equation) shows high performances by the model in estimating the LWC peak over the boundary, while water speed in snow is underestimated by the chosen water transport scheme.
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Dorgan, Kelly M., Grant Lockridge, Madeline R. Frey, et al. "Relating tensile strength to acoustic and biological properties of sediments along a mud-sand gradient in Mobile Bay, AL." Journal of the Acoustical Society of America 150, no. 4 (2021): A350. http://dx.doi.org/10.1121/10.0008550.
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Nearshore and estuarine sediments experience varying sediment inputs that create sharp gradients in sediment properties over fairly small vertical and horizontal distances. In this study, we explored the sand-mud transition in sediment cores collected from Mobile Bay, AL, with acoustic and geotechnical approaches. A custom built instrument was used to measure depth profiles of tensile strength at cm-scale resolution. These measurements were compared to acoustic sound speed and attenuation across a range of frequencies. Cores collected exhibited a horizontal gradient from sand to mud across the study area with a sandy layer on top of muddier sediment in most cores. This study explicitly examines the relationship between acoustic sound speed and attenuation and strength-related properties of sediments such as cohesion that can be measured in situ more easily than textural properties (e.g., porosity and grain size). We compare our data to in situ normal incidence measurements and portable free fall penetrometer data as well as infaunal community composition to better relate acoustic, geotechnical, and biological properties across a gradient of sediments.
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Bazhan, Ihor, Oleksii Vasylkovskyi, Serhii Leshchenko, and Volodymyr Amosov. "Intensification of the Grain sEparation Process on a Flat Oscillating Sieve with a Zigzag Arrangement of Holes." National Interagency Scientific and Technical Collection of Works. Design, Production and Exploitation of Agricultural Machines, no. 54 (2024): 192–202. https://doi.org/10.32515/2414-3820.2024.54.192-202.
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Increasing the quantitative and qualitative performance of agricultural machinery is a pressing task for scientists conducting research in the field of agricultural engineering. This article is devoted to the analysis of methods and means of intensification of intralayer processes occurring in grain material during sieve separation in order to increase the efficiency of grain cleaning by size on flat-screen vibrating machines. A review of technical solutions that ensure increased efficiency of sieve cleaning of grain materials on flat-screen vibrating separators was conducted. Analysis of technical solutions allowed to identify the physical bases of the appearance of the effect of increasing the indicators of technological efficiency of sieve processing of grain. It was established that an increase in separation efficiency can be achieved only by intensifying the processes of mutual movement (segregation) of particles inside the layer of material in the vertical and horizontal planes. It was assumed that the most effective is the activation of intralayer processes in the processed material, which is provided in two ways – by establishing the optimal kinematic mode of oscillations and the structural parameters of the sieve itself. A new, patented technical solution is presented – a sieve with a zigzag arrangement of holes and the main tasks and elements of the methodology of previous studies are formed. Conclusions. Increasing the efficiency of the flat-screen vibrating working bodies can be achieved only by intensifying the intralayer processes in the processed material. Activating the intralayer processes is achieved in two main ways – by establishing optimal modes and by using structural activators, and their directions of action mostly do not coincide. The use of the regime activation method intensifies the processes mostly in the vertical plane, contributing to the segregation of particles, while the use of structural elements allows improving the conditions in the horizontal plane (in the plane of the sieve). At the same time, the use of additional devices complicates the design. The most organic way to intensify intralayer processes in the processed material is to use flat sieves with a zigzag arrangement of oblong holes, which activate their interaction with particles of the grain mixture in the longitudinal and transverse directions and to match the structural parameters of the sieve with the operating parameters of the oscillations.
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Zhao, Y., Jian Xiao, and S. J. Chen. "Comparison of Microstructure and Mechanical Properties of Aluminum Components Manufactured by CMT." Materials Science Forum 898 (June 2017): 1318–24. http://dx.doi.org/10.4028/www.scientific.net/msf.898.1318.
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This paper presents an investigation on the microstructure and mechanical property of Al-alloy parts made by using additive manufacturing based on CMT (Cold Metal Transfer) welding technology. With the same 3D model and process parameters, a set of hollow cylindrical parts with 100 layers were built up using 2319, 4043, 5356 aluminum welding wires, respectively. Then their microstructure, tensile strength, and microhardness were tested and analyzed comparatively. The layer bands characteristics were obviously observed in both 2319 and 4043 parts. In the interlayer region of the 2319 parts, the segregation of alloying elements on the grain boundaries and inside the grains were significantly more than that in the fusion line region. For the microstructure of 4043 parts, the dendrites grow upward from the bottom without interruption in the fusion line region, and the continuous growth structure was maintained. There is no obviously change on the microhardness from the bottom to the top because the organization is uniform and there is no significant difference in the grain size. The ultimate strength and elongation in the horizontal direction were higher than those in the longitudinal direction, and the 5356 parts had best mechanical properties among the three materials. Ultrasonic method was also used to measure the Young's modulus of the additive manufactured parts. The Young's modulus measuring results were accordant with the results obtained by the mechanical property testing, and the error was within 3%.
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Akhtar, Shazeen, Naveed Akhtar, Irfan Nadeem, and Anjum Tauqir. "Rapid Solidification and Surfaces Alloying Using Continuous CO2 Laser to Generate Ni-Aluminide on Steel." Key Engineering Materials 875 (February 2021): 329–36. http://dx.doi.org/10.4028/www.scientific.net/kem.875.329.
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Rapidly solidified thin micro-alloyed surface layers are generated by laser melting of plasma thermal sprayed steel surfaces. Samples of carbon steel are plasma sprayed with fine nickel and aluminum powders. Laser surface melting generated a thin localized molten pool of metal with steep horizontal thermal gradient. The latter triggered intense vortex formation in the molten pool which thoroughly mixed the nickel and aluminum powders within the molten pool in a fraction of a second. As the sample is moved away with a predefined velocity, the cold substrate quenched the melt pool, generating rapidly solidified micro-alloyed surfaces. A 2.5 kilowatts continuous carbon dioxide laser was used for surface melting; laser power was maintained at 800 watts while the samples were moved with respect to the laser beam at linear velocities in the range of 100-200 mm/min. The technique generated metallurgical bonded novel surfaces. Depth of the laser modified layer was achieved in the range of 0.2-0.4 mm. Refined microstructures of pre-austenite grain size in the range of 4±2 µm were generated. Micro-hardness measurements of the modified layer indicate an almost three times enhancement in the hardness values; the latter are, in general indicative of mechanical strength of the material. The shape of the solid/liquid interface of the advancing molten pool determines the orientation of the growing dendrites; at higher velocities of sample translation with respect to the laser beam, these are almost parallel to the sample surface. The orientation of the dendrites, the uniformity in surface alloying (within fraction of a second) and the resulting hardness values are explained with the help of the modeled shape of the liquid metal pool. The laser processed material proved to be a flexible technique to synthesize novel surfaces for surface sensitive applications.
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Avanzi, Francesco, Hiroyuki Hirashima, Satoru Yamaguchi, Takafumi Katsushima, and Carlo De Michele. "Observations of capillary barriers and preferential flow in layered snow during cold laboratory experiments." Cryosphere 10, no. 5 (2016): 2013–26. http://dx.doi.org/10.5194/tc-10-2013-2016.
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Abstract. Data of liquid water flow around a capillary barrier in snow are still limited. To gain insight into this process, we carried out observations of dyed water infiltration in layered snow at 0 °C during cold laboratory experiments. We considered three different finer-over-coarser textures and three different water input rates. By means of visual inspection, horizontal sectioning, and measurements of liquid water content (LWC), capillary barriers and associated preferential flow were characterized. The flow dynamics of each sample were also simulated solving the Richards equation within the 1-D multi-layer physically based snow cover model SNOWPACK. Results revealed that capillary barriers and preferential flow are relevant processes ruling the speed of water infiltration in stratified snow. Both are marked by a high degree of spatial variability at centimeter scale and complex 3-D patterns. During unsteady percolation of water, observed peaks in bulk volumetric LWC at the interface reached ∼ 33–36 vol % when the upper layer was composed by fine snow (grain size smaller than 0.5 mm). However, LWC might locally be greater due to the observed heterogeneity in the process. Spatial variability in water transmission increases with grain size, whereas we did not observe a systematic dependency on water input rate for samples containing fine snow. The comparison between observed and simulated LWC profiles revealed that the implementation of the Richards equation reproduces the existence of a capillary barrier for all observed cases and yields a good agreement with observed peaks in LWC at the interface between layers.
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Żyła, Mieczysław, Agnieszka Dudzińska, and Janusz Cygankiewicz. "The Influence of Disintegration of Hard Coal Varieties of Different Metamorphism Grade on the Amount of Sorbed Ethane / Wpływ rozdrobnienia odmian węgla kamiennego o różnym stopniu metamorfizmu na ilości sorbowanego etanu." Archives of Mining Sciences 58, no. 2 (2013): 449–63. http://dx.doi.org/10.2478/amsc-2013-0030.
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Ethane constitutes an explosive gas. It most often accompanies methane realizing during exploitation and mining works. In this paper the results of ethane sorption have been discussed on three grain classes of six selected hard coal samples collected from active Polish coalmines. On the basis of obtained results, it has been stated that the tested hard coals prove differentiated sorption power with reference to ethane. Te extreme amount of ethane is sorbed by low carbonized hard coal from “Jaworzno” coalmine. This sort of coal shows great porosity, and great content of oxygen and moisture. The least amount of ethane is sorbed by hard coal from “Sośnica” coalmine. This sort of coal possesses relatively a great deal of ash contents. Together with the process of coal disintegration, the amount of sorbed ethane increases for all tested coal samples. Between tested coals there are three medium carbonized samples collected from “Pniówek”, “Chwałowice” “Zofiówka” coalmines which are characterized by small surface values counted according to model BET from nitrogen sorption isotherms determined at the temperature of 77.5 K. The samples of these three coals prove the highest, from between tested coals, increase of ethane sorption occurring together with their disintegration. These samples disintegrated to 0,063-0,075 mm grain class sorb ethane in the amount corresponding with the sorption quantity of low carbonized coal from “Jaworzno” coalmine in 0.5-0.7 mm grain class. It should be marked that the low carbonized samples collected from “Jaworzno” and Wesoła” coalmines possess large specific surface and great porosity and belong to coal group of “loose” spatial structure. Regarding profusion of sorbed ethane on disintegrated medium carbonized samples from “Pniówek”, “Zofiówka”, “Chwałowice” coalmines it can be supposed that in the process of coal disintegration, breaking their “compact’ structure occurs. Loosened structure of medium carbonized coals results in increasing accessibility of ethane particles to sorption centres both electron donors and electron acceptors which are present on hard coal surface. The surface sorption centre increase may result in formation a compact layer of ethane particles on coal surface. In the formed layer, not only the strengths of vertical binding of ethane particles with the coal surface appear but also the impact of horizontal strengths appears which forms a compact layer of sorbed ethane particles. The surface layer of ethane particles may lead to explosion.
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Lee, Chang-Hee, Shin-Han Kim, Yeonjin Yi, Jeong-Hwan Lee, and Gi-Dong Lee. "P‐196: Control of the Molecular Orientation in EML Using Substrate Temperature for Improving the Electro‐Optical Characteristics and Lifetime." SID Symposium Digest of Technical Papers 55, no. 1 (2024): 2134–37. http://dx.doi.org/10.1002/sdtp.18027.
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In this paper, we controlled the molecular alignment property of the EML layer in horizontal direction by changing the substrate temperature (Tsub) during deposition at ‐4, 20, and 40 °C and observed the effect of molecular orientation characteristics of the EML on the electro‐optical characteristics and the lifetime of OLED devices. The color property of the devices fabricated in different Tsub show same properties, but the optical performance of the cells fabricated at ‐4 °C was better than those fabricated at high temperatures as we expected due to the horizontal component of the molecular orientation. In particular, as for the lifetime of the cell, we observed over 4 times longer lifetime of the cell fabricated at ‐4 °C than the cell fabricated at 40 °C. To analyze the cause of the increase in lifetime, we also observed the surface roughness and grain boundary of the EML fabricated in each Tsub conditions. In addition, more detail data including binding energies between the molecule and deformation data using major molecule weight are also presented either. As a result, we confirm that the Tsub during deposition strongly affects to the molecular anisotropy factor and we can improve the electro‐optical and lifetime performance of the OLED cell through low Tsub.
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Исенов, Isenov Kazbek Galymtaevich, Шынар Искакова, Махашева Сымбат, Жанна Кубашева, and Амангельды Сарсенов. "GEOMETRIC CLAMPING PLATE DIMENSIONS OF THE IMPROVED OF GRAIN SEEDER COULTER SZ-3,6." Ġylym ža̋ne bìlìm 3, no. 2 (71) (2023): 70–78. http://dx.doi.org/10.52578/2305-9397-2023-2-3-70-78.
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The article notes that the improvement of operating tools of sowing machines is a solution to one of the many tasks of increasing crop yields. It is also noted that a two-disc coulter and its inherent advantages and disadvantages have been widely used on sowing machines, and the final sowing operation is considered the most important for seeds, since it creates conditions for their germination and further development.
 Significant factors affecting the germination and development of plants after sowing with seeders equipped with disc coulters are given, one of which is the tight contact of seeds with the bottom groove with a loose surface layer.
 The scheme for improving a two-disc coulter with pressure plate installed in the inter-disc space is proposed, and the details of the coulters are maximally unified with the coulters of grain seeders of the type SZ-3.6, mass-produced by domestic manufacturers. The pressure plate, moving together with the coulter, crushes small soil lumps with the inclined part and pushes the seeds into the bottom groove with a horizontal shank, ensuring their tight contact with the soil. A method for determining the main geometric parameters of the pressure plate depending on external forces acting from the soil is proposed, the dependence of the characteristics of the cross-section of the plate on the geometric dimension is given
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Vincent, G. E. "CONTRIBUTION TO THE STUDY OF SEDIMENT TRANSPORT ON A HORIZONTAL BED DUE TO WAVE ACTION." Coastal Engineering Proceedings 1, no. 6 (2011): 20. http://dx.doi.org/10.9753/icce.v6.20.
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With a view to explaining the phenomena of sediment transport in the open sea, outside the wave breaking area, the author carried out a laboratory investigation of wave action on a horizontal bed. He puts forward a number of new results regarding : 
 
 1 - The state of turbulence near the bed and the stability of the oscillatory laminar boundary layer.
 2 - The setting in notion of materials under the influence of wave alone.
 3 - The entrapment current caused by wave action close to the bed.
 4 - The transport of material under wave action only.
 5 - The indirect action of wave on the bed.
 The main conclusions reached are as follows :
 1/ - The results given by Kuon Li regarding the onset of turbulence within the oscillatory boundary layer overestimate the range of laminar conditions. Vo (maximum orbital velocity) and e (roughness) are the principle factors governing the transition. Test waves are either generally laminar, or are only slightly turbulent within the body of liquid, but they are, however, more often turbulent in the immediate neighbourhood of the bed.
 2/ - The Investigation of conditions for the onset of grain movement of the bed material shows that the action of wave can be appreciable, even at depths of several tens of metres. A wave of 6 metres amplitude, with a total length of 120 metres, would be capable of putting a 0.3 mm sand grain into motion at a depth of 60 metres.
 3/ - The experimental investigation, as well as the viscous fluid theory, shows the existence, close to the bed, of an entrainment current of liquid particles which always works In the direction of wave propagation.
 4/ - In test flumes, this entrainment current forms part of a mass transport within the liquid, the vertical distribution of which varies with the characteristics of the fluid motion. On a horizontal bed, It generally gives rise to an effective sediment transport, in the direction of wave propagation, as the preponderant part of the liquid velocity component, near the bed. is in this direction.
 5/ - Owing to the existence of the pass transport current and the onset of suspension of material above the bed, some sediment transport can exist out to sea. These results give an explanation of why, under the action of long and regular wave . material tends to be carried in the direction of the waves and build up on the beach whereas, under storm conditions, a strong resultant turbulence produces suspension and favours erosion of the beach.
 6/ - On a sloping bed, transport towards the shore is counterbalanced by the effect of gravity, currents caused by winds from seaward and density currents set up in the wave break area so that finally material eroded from land surfaces are, In part, gradually carried away towards the open sea.
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Konischev, A. "Past and future for tillage for grain crops." Agrarian Bulletin of the 194, no. 3 (2020): 21–27. http://dx.doi.org/10.32417/1997-4868-2020-194-3-21-27.
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Abstract. The purpose of the research is to show and explain why it is impossible to eliminate anthropogenic soil compaction and reduce the dependence of crop productivity on the weather conditions of the growing season with the help of first-generation soil cultivation technologies. Methods. To achieve this goal, the analysis of the impact of the results of the application of first-generation technologies on the yield of cultivated crops. On the basis of which, with the help Of the theory of solving inventive problems, the laws of creating second-level technologies are developed and the directions of their implementation are determined. The scientific novelty lies in the development of a new direction of improving the technology of soil cultivation for crops. Results. It is established that the creation of the first generation of technologies took place on the “layer-plane” principle, implemented according to the scheme “deep-less deep-very shallow”. Given that plants for maximum productivity does not need any specific soil density, and requires an optimal combination of density and moisture regime, this led to a chronic predisposition of the first generation technologies to anthropogenic soil compaction and complete dependence of crops on current weather conditions. It is possible to eliminate the specified lacks at transition to technologies of the second level. By abandoning today's “horizontal” principle of minimizing processing, and moving to minimize the “vertical”, when not all the area of the field will be processed to the same depth and with the same intensity. In practice, this is realized by dividing the entire area of the field into many micro plots, each of which creates a soil density that provides maximum yield under a particular regime of moisture. Mutual influence and addition of sites to each other reduces the overall dependence of crop yield on weather conditions of the growing season. The increase in barley yield is up to 11 % compared to the technology based on plowing and up to 20 % compared to the minimum processing. Spring wheat, respectively: 15 % and 23 %.
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Li, Wei, Dong Lin Xia, Ming Xia Song, Zhen Zhong Zhang, Jia Miao Ni, and Xiu Jian Zhao. "Nickel Induced Lateral Crystallization of Amorphous Silicon Film by Electroless Planting." Advanced Materials Research 66 (April 2009): 147–50. http://dx.doi.org/10.4028/www.scientific.net/amr.66.147.
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A novel deposition way of nickel film for crystallization amorphous silicon film is introduced. Electroless nickel planting is a convenient and inexpensive way to deposit nickel without using the electric field or any large facility. A 200 nm nickel film is deposited on the glass substrates and then a 300nm a-Si film is deposited on the nickel film with a horizontal electric field assisted to enhance amorphous silicon crystallization. The bi-layer film is annealed at 500°C for several hours in the nitrogen atmosphere. The crystallized Si thin films were characterized by Raman spectroscopy, Field emission scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The Raman demonstrates that the a-Si has been crystallized. Furthermore the FE-SEM shows the lateral crystalline morphology, the length of grain is up to 5µm and the EDS reveals the nickel distribution in the MILC and MIC area.
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Amer, Mohamed, Nicholas Curry, Qamar Hayat, et al. "Cracking Behavior of Gd2Zr2O7/YSZ Multi-Layered Thermal Barrier Coatings Deposited by Suspension Plasma Spray." Coatings 13, no. 1 (2023): 107. http://dx.doi.org/10.3390/coatings13010107.
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A new multi-layered thermal barrier coating system (TBCs) containing gadolinium zirconate (GZ, Gd2Zr2O7) and yttria-stabilized zirconia (YSZ) was developed using suspension plasma spray (SPS) to improve the overall thermal cycling performance. This study focuses on the cracking behavior of the GZ/YSZ TBC after thermal exposure to find out the key factors that limit its lifetime. Different cracking behaviors were detected depending on the thermal treatment condition (i.e., horizontal cracks within the ceramic layer and at the thermally grown oxide (TGO)/YSZ interface) which can be related to stresses developed through thermal expansion mismatch and increased TGO thickness beyond a critical value, respectively. A reduction in hardness of bond coat (BC) was measured by nanoindentation and linked with the thermally activated grain growth mechanism. The hardness and elastic modulus of ceramic layers (GZ and YSZ) showed an increased trend after treatment that contributed to the interfacial cracks.
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Zhao, D., S. Brezinsek, R. Yi, et al. "Investigation of boron distribution and material migration on the W7-X divertor by picosecond LIBS." Physica Scripta 97, no. 2 (2022): 024005. http://dx.doi.org/10.1088/1402-4896/ac4a93.
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Abstract One set of horizontal target elements of the Test Divertor Units (TDU), retrieved from the Wendelstein 7-X (W7-X) vessel after the end of second divertor Operation Phase (OP1.2B) in Hydrogen (H), were investigated by picosecond Laser-Induced Breakdown Spectroscopy (ps-LIBS). The Boron (B) distribution, H pattern and the material erosion/deposition pattern on these target elements were analyzed with high depth resolution and mapped in the poloidal direction of W7-X. From the spectroscopic analysis, B, H, Carbon (C) and Molybdenum (Mo) were clearly identified. A non-uniformly distributed B pattern on these divertor target elements was determined by the combination of B layer deposition during the three boronizations and W7-X plasma operation with multiple erosion and deposition steps of B. Like the TDU, the analyzed target elements are made of fine grain graphite, but have two marker layers which allow us to determine the material migration via the ps-LIBS technique. Two net erosion zones including one main erosion zone with a peak erosion depth of 6.5 μm and one weak erosion with a peak erosion of 1.3 μm were determined. Between two net erosion zones, a net deposition zone with width of 135 mm and a thickness up to 3.5 μm at the peak deposition location was determined by the ps-LIBS technique. The B distributions are correlated with the erosion/deposition pattern and the operational time in standard magnetic configuration of W7-X in the phases after the boronizations. The thickness of the containing B layer on these target elements also correlates with the erosion/deposition depth, in which the thickness of the containing B layer varies spatially in poloidal direction between 0.1 μm and 6 μm. Complementary, Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) was employed also to verify and investigate the deposition layer thicknesses at typical net erosion and net deposition zones as well as to identify the three boronizations in depth.
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Qian, Jin, Xiujuan Wang, Timothy S. Collett, et al. "Gas hydrate accumulation and saturations estimated from effective medium theory in the eastern Pearl River Mouth Basin, South China Sea." Interpretation 5, no. 3 (2017): SM33—SM48. http://dx.doi.org/10.1190/int-2016-0217.1.
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Pore- and fracture-filling gas hydrates were identified from the core samples at several sites during the second Guangzhou Marine Geological Survey (GMGS2) expedition. Well logs indicated that gas hydrate occurred in three distinct layers at site GMGS2-08. The gas hydrate saturations calculated from well-log data and the seismic responses for the three gas hydrate-bearing layers, especially within the middle carbonate layer, were poorly known. We estimated gas hydrate saturations using isotropic and anisotropic models based on the mineral composition of the sediments and the effective medium theory. In the upper and lower gas hydrate-bearing layers, saturations estimated from anisotropic models are close to those estimated from pressures cores and chlorinity data. The average saturation using an anisotropic model in the upper (fracture-dominated) hydrate layer is approximately 10% with a maximum value of 25%. In the lower (fracture-dominated) layer, the horizontal and vertical gas hydrate-filled fractures and visible gas hydrate were formed with a maximum saturation of approximately 85%. For the middle layer, well logs show high P-wave velocity, density, high resistivity as well as low gamma ray, porosity, and drilling rate, together indicating a carbonate layer containing gas hydrate. The hydrate saturations calculated from isotropic models assuming hydrate formed at grain contacts are less than 20%, which fit well with two values calculated from chlorinity data for this layer. The upper gas hydrate layer shows no clear seismic response and probably consisted of small fractures filled with gas hydrate. The middle carbonate and lower fracture-filled gas hydrate-bearing layers show pull-up reflections, with the carbonate layer exhibiting relatively higher amplitudes. Pore-filling gas hydrate was also identified just above the depth of the bottom-simulating-reflector (BSR) from the GMGS2-05 drill site. Below the BSR, the push-down reflections, polarity reversal, and enhanced reflections indicate the occurrence of free gas in the study area.
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Krokhalev, A. V., V. O. Kharlamov, D. R. Chernikov, S. V. Kuz’min, and V. I. Lysak. "Using explosion loading to obtain coatings of chromium carbide and titanium mixtures in deposition mode." Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya, no. 2 (June 16, 2022): 70–78. http://dx.doi.org/10.17073/1997-308x-2022-2-70-78.
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The paper presents the results of studies into the microstructure, chemical and phase composition of coatings deposited on a steel substrate using the sliding explosive loading of Cr3C2 chromium carbide and titanium powder mixtures. The equilibrium phase composition of coatings was calculated by computational thermodynamic modeling using the Thermo-Calc software package. The structure and elemental composition were studied using a FEI Versa 3D scanning electron microscope with an integrated EDAX Apollo X system for energy dispersive X-ray microprobe analysis. A Bruker D8 Advance diffractometer was used for X-ray phase analysis. It was shown that when the powder layer is loaded by a sliding detonation wave, it can be shifted along the substrate surface due to the horizontal mass velocity component of compacted material particles. This shift causes the inner layer of the compacted powder and the surface layer of the substrate to melt as a result of friction. The presence of a liquid phase prevents the compacted powder layer deceleration so that the major part of it is removed from the substrate surface. The liquid phase remaining on the surface undergoes rapid quenching due to heat removal into the substrate and forms a deposited coating containing both the components of the initial powder mixture and the components of the substrate to be coated. It was established that the deposited layer structure features by extremely high dispersion (grain size does not exceed 250 nm), and its phase composition turns out to be close to a thermodynamically equilibrium one. When using powder mixtures of chromium carbide with 40% titanium, a coating is formed consisting of titanium carbide with a metal binder based on solid solutions of iron and titanium in chromium.
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Perchuk, A. L., A. A. Serdyuk, and N. G. Zinovievа. "Subduction sediment-lherzolite interaction at 2.9 GPa: effects of metasomatism and partial melting." Петрология 27, no. 5 (2019): 503–24. http://dx.doi.org/10.31857/s0869-5903275503-524.
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We present the results of analogue experiments carried out in a piston–cylinder apparatus at 750–900°C and 2.9 GPa aimed to simulate metasomatic transformation of the fertile mantle caused by fluids and melts released from the subducting sediment. A synthetic H2O- and CO2-bearing mixture that corresponds to the average subducting sediment (GLOSS, Plank, Langmuir, 1998) and mineral fractions of natural lherzolite (analogue of a mantle wedge) were used as starting materials. Experiments demonstrate that the mineral growth in capsules is controlled by ascending fluid and hydrous melt (from 850°C) flows. Migration of the liquids and dissolved components develops three horizontal zones in the sedimentary layer with different mineral parageneses that slightly changed from run to run. In the general case, however, the contents of omphacite and garnet increase towards the upper boundary of the layer. Magnesite and omphacite (± garnet ± melt ± kyanite ± phengite) are widespread in the central zone of the sedimentary layer, whereas SiO2 polymorph (± kyanite ± phengite ± biotite ± omphacite ± melt) occurs in the lower zone. Clinopyroxene disappears at the base of lherzolite layer and the initial olivine is partially replaced by orthopyroxene (± magnesite) in all experiments. In addition, talc is formed in this zone at 750°C, whereas melt appears at 850°C. In the remaining volume of the lherzolite layer, metasomatic transformations affect only grain boundaries where orthopyroxene (± melt ± carbonate) is developed. The described transformations are mainly related to a pervasive flow of liquids. Mineral growth in the narrow wall sides of the capsules is probably caused by a focused flow: omphacite grows up in the sedimentary layer, and talc or omphacite with the melt grow up in the lherzolite layer. Experiments show that metasomatism of peridotite related to a subducting sediment, unlike the metasomatism related to metabasites, does not lead to the formation of garnet-bearing paragenesis. In addition, uprising liquid flows (fluid, melt) do not remove significant amounts of carbon from the metasedimentary layer to the peridotite layer. It is assumed that either more powerful fluxes of aqueous fluid or migration of carbonate-bearing rocks in subduction melanges are necessary for more efficient transfer of crustal carbon from metasediments to a mantle in subduction zones.
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Tishaninov, Nikolay, and Sergey Emelyanovich. "JUSTIFICATION OF THE PARAMETERS OF THE BELT FEEDER TO SUPPLY THE IMPURITY TO THE EXPERIMENTAL TRIER." SCIENCE IN THE CENTRAL RUSSIA, no. 1 (February 28, 2023): 5–13. http://dx.doi.org/10.35887/2305-2538-2023-1-5-13.
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The requirements and technical possibilities for ensuring the reproducibility of experimental conditions in the study of screener technologies for cleaning grain mixtures in terms of the stability of their component composition over time, by means of separate feeding of components into the screener, are substantiated. A belt feeder that makes it possible to ensure the reproducibility of experiments with the initial clogging of the grain mixture in the range Zi = 1 - 3% and the productivity of the trier WT = 1.2 - 4.35 t / h is proposed for impurity components with high particle cohesion (oats, wild oats). The distribution of the impurity component along the length of the tape is carried out by means of a box without a bottom. The parameters of the box section were adopted based on the analysis of the contradiction, which consists in the fact that an increase in the horizontal section of the box (Sk) leads to an increase in the relative error in the distribution of the impurity component during its laying, and a decrease in Sk increases the dynamics of the formation of an impurity layer on the tape, reducing the efficiency of using its width. The box parameters turned out to be preferable for the experimental conditions at Zi = 1 - 3% and Wt = 1.2 - 4.35 t/h: width - 60 mm; height - 70 mm. A significant influence of the dynamics of the formation of an impurity layer on the tape was experimentally established: the angle of repose decreases by a factor of 2.5 (30° to 12°); the layer width increases by 1.6 times (from 170 mm to 270 mm). Reducing the dynamic impact on the impurity component by reducing the height of the box leads to a decrease in the efficiency of using the width of the tape - the cross section of the impurity layer becomes trapezoidal. Prevention of impurity losses in the feeder operation is ensured by flexible collars fixed on the edges of the belt. The qualitative distribution of impurities along the length of the box in experiments with partial loading of the trier is carried out by a special leveler - a vertical gate placed in a slider with the possibility of adjusting the position and fixing it with a clamp. To control the distribution of impurities in the box, it is advisable to make at least one of its side walls from a transparent material.
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Gil-Plazas, Andres-Fernando, Julián-David Rubiano-Buitrago, Luis-Alejandro Boyacá-Mendivelso, and Liz-Karen Herrera-Quintero. "Solid-State and Super Solidus Liquid Phase Sintering of 4340 Steel SLM Powders Shaped by Fused Filament Fabrication." Revista Facultad de Ingeniería 31, no. 60 (2022): e13913. http://dx.doi.org/10.19053/01211129.v31.n60.2022.13913.
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4340 steel powders were processed with an additive manufacturing process using the FFF (Fused Filament Fabrication) technique. A composite filament was developed to print samples and study the effect of the bed and nozzle temperatures on its physical and microstructural properties. The printed samples were debinded and sintered by: Solid State (SS) at 1300 °C or SLPS (Supersolidus Liquid Phase Sintering) at 1420 °C. Metallography and scanning electron microscopy (SEM) identified the microstructure and phases. The hardness of the sintered samples was measured with the Vickers method. The SLPS process contributes to better densification and volume contraction; however, it promotes geometrical distortion of the samples compared to the SS samples. The microstructure of the sintered samples consists of ferrite situated in the original austenite grain and bainite. The sintering mechanism significantly influenced the hardness of the samples. Finally, a part was designed, printed, debinded, and sintered with the aim of studying the maximum inclination angle, the minimum vertical and horizontal holes, and the minimum vertical layer thickness, which can be obtained through the whole process.
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Zhang, Tao, Lei Li, and Shihong Lu. "Analysis of deformation characteristics and microstructure variation of thick plate during asymmetric shear rolling." MATEC Web of Conferences 190 (2018): 11004. http://dx.doi.org/10.1051/matecconf/201819011004.
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Aluminium alloy thick plate is widely used in field of aerospace and automobile industry for its light weight, high strength, good corrosion resistance and formability. Hot rolling is the key process of preparation for thick plates, however, the conventional symmetrical rolling process causes large deformation on the surface and small deformation in the central portion of the thick plate, resulting in inhomogeneous deformation, microstructure and property distributions through the thickness direction of the plate. Asynchronous rolling is beneficial for deformation permeation into the central part of thick plate with introduction of strong shear strain due to velocity asymmetry of two work rolls. However, the plate will bend towards the slower roll due to deformation asymmetry at upper and lower surface of the plate and serious bending is bad for multi-pass rolling process. Asymmetrical shear rolling with velocity asymmetry and geometry asymmetry is adopted in this study. Compared to asynchronous rolling, there is a horizontal offset distance of upper roll in outlet direction. A moment will be applied to the plate in the opposite direction of bending towards the slower roll by an offset distance of the slower roll. The comparisons of distributions of equivalent strain, temperature, DRX fraction and average grain size between symmetrical rolling and asymmetrical shear rolling are studied. The effects of velocity asymmetry and offset distance on microstructure variation and microstructure distribution at different positions of the plate are studied. Due to larger velocity of lower work roll, larger equivalent strain and higher temperature appear at lower layer of the plate, which results in higher DRX fraction and finer grain size. The speed ratio contributes greatly to sufficient DRX process and finer grain size; while the ascending offset distance decreases the DRX fraction. Therefore, speed ratio plays significant role in deformation permeation and grain refinement in asymmetrical shear rolling and the offset distance is mainly used to decrease the bending behaviour of the plate. This study can provide guidance to thick plate preparation with good properties in asymmetrical rolling process.
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Xie, Bin, Jiaxiang Xue, Xianghui Ren, Wei Wu, and Zhuangbin Lin. "A Comparative Study of the CMT+P Process on 316L Stainless Steel Additive Manufacturing." Applied Sciences 10, no. 9 (2020): 3284. http://dx.doi.org/10.3390/app10093284.
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Adopting the cold metal transfer plus pulse (CMT + P) process, 316L stainless steel wire was treated with a single channel multi-layer deposition experiment under different linear energy. The microstructures of different regions on the deposited samples were observed by optical microscope and scanning electron microscope, and the element distribution in the structure was analyzed by energy dispersive spectrometer. The mechanical properties and microhardness were measured by tensile test method and microhardness tester, respectively, and the anisotropy of tensile strength in horizontal and vertical directions were calculated. Finally, the fracture morphology of the tensile samples were observed by SEM. Experiment results showed that when the difference between the actual and the optimal wire feeding speed matching the specific welding speed was too large, this led to an unstable deposition process as well as flow and collapse of weld bead metal, thus seriously deteriorating the appearance of the deposition samples. The results from metallographic micrograph showed that rapid heat dissipation of the substrate caused small grains to generate in the bottom region of deposition samples, then gradually grew up to coarse dendrites along the building direction in the middle and top region caused by the continuous heat accumulation during deposition. Tensile test results showed that with the increase of linear energy, the horizontal and vertical tensile strength of the as-deposited samples decreased. In addition, the higher linear energy would deteriorate the microstructure of as-deposited parts, including significantly increasing the tendency of oxidation and material stripping. The microhardness values of the bottom, middle and top regions of the samples fluctuated along the centerline of the cross-section, and the values showed a trend of decreasing first and then rising along the building direction. Meanwhile, the yield strength and tensile strength of each specimen showed obvious anisotropy due to unique grain growth morphology. On the whole, the results from this study prove that CMT+P process is a feasible MIG welding additive manufacturing method for 316L stainless steel.
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Luca, Mihai Alexandru, and Teodor Machedon-Pisu. "The Influence of Vibration on the Microstructure of the Wear-Resistant Layer Made with the Welding Wire MSG-6-GZ-C-60G." Advanced Materials Research 1029 (September 2014): 94–99. http://dx.doi.org/10.4028/www.scientific.net/amr.1029.94.
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In the production of steel parts exigent of high durability to abrasive wear at high temperatures and / or corrosive environment, the method is used for the deposition welding with the addition material MSG-6-GZ-C-60G. With this material layer it is made of 55-60 HRC hardness, corrosion and wear resistant, with properties that are kept up to temperatures of 5000 C. There can be manufactured new parts (pressure casting forms, components for dies, molds, etc.), or dynamically and abrasion-torn reconditioned parts may be required. Deposits have been made with wear-resistant layer on the steel 42CrMo4, with and without the generation of vibration during welding. For the samples swing, a device was used with an electrodynamic exciter to generate vibrations with frequencies up to 20 kHz. Vibration tests were performed at a frequency of 50 Hz, because the frequency can be applied in industrial conditions, by means of excitation of electromagnetic or vibration driven motor. There have been registered horizontal and vertical accelerations which lead to changes in the conditions of crystallisation of the melt, respectively the formation of a microstructure with superior features. Microstructures and hardness recorded on specimens welded with and without vibration are comparatively presented. Micrographs which were made demonstrate the favourable influence of the vibration on the quality of the deposited layer and the base material. Whith the vibration with accelerations of ax= 55 m/s2and az= 70 m/s2resulted: much lower deformation of the base material, HAZ - a lower content of residual austenite, in the TZ there was a great interlock of the two materials, in the deposited material the dendritic crystals strongly fragmented and the grain was finished.
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Ren, Lingling, Huimin Gu, Wei Wang, et al. "Effect of Mg Content on Microstructure and Properties of Al–Mg Alloy Produced by the Wire Arc Additive Manufacturing Method." Materials 12, no. 24 (2019): 4160. http://dx.doi.org/10.3390/ma12244160.
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In this study, an Al–Mg alloy was fabricated by wire arc additive manufacture (WAAM), and the effect of Mg content on the microstructure and properties of Al–Mg alloy deposits was investigated. The effects on the deposition surface oxidation, geometry, burn out rate of Mg, pores, microstructure, mechanical properties and fracture mechanisms were investigated. The results show that, when the Mg content increased, the surface oxidation degree increased; a “wave”-shaped deposition layer occurred when the Mg content reached 8%. When the Mg content was more than 6%, the burning loss rate of the Mg element increased significantly. With the increase of Mg content, the number of pores first decreased and then increased, and the size first decreased and then increased. When the Mg content reached 7% or above, obvious crystallization hot cracks appeared in the deposit bodies. When the Mg content increased, the precipitated phase (FeMn)Al6 and β(Mg2Al3) increased, and the grain size increased. When the Mg content was 6%, the comprehensive mechanical properties were best. The horizontal tensile strength, yield strength and elongation were 310 MPa, 225 MPa and 17%, respectively. The vertical tensile strength, yield strength and elongation were 300 MPa, 215 MPa and 15%, respectively. The fracture morphology was a ductile fracture.