bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research Status and Prospect of Residual Plastic Film Pickup Mechanism in China
Authors: Zhang Yaxin , Zhang Jiahua , Li Shaohua , Zhang Yumei , Li Hang 
Published: February 2021

Abstract
Plastic film mulching technology not only improves the yield, but also brings white pollution. In order to solve the problem of residual film recovery, a large number of plastic film collecting machines have been designed in China. The film picking mechanism is the key part of the residual film recovery machine. Its mechanism form and operation quality play an important role in improving the recovery rate of the residual film. This paper analyzes the development status of the film collecting mechanism of the residual film recycling machine at home and abroad, briefly introduces the structure and working principle of seven kinds of residual film collecting mechanisms, including Winding type, telescopic rod type, elastic tooth type, gear teeth type, drum type and pneumatic type. This study provides relevant suggestions for the optimization and improvement of the film collecting mechanism in the future.
An improved hybrid genetic algorithm for holes machining path optimization using helical milling operation
Authors: Li Z Q , Liu X , Duan L S , Liu L 
Published: February 2021

Abstract
Helical milling is capable of fabricating a lot of holes with only one cutting tool under one clamping. As the holes machining efficiency is determined by the holes machining time and the airtime, and when the cutting conditions of helical milling operation is determined, holes machining path optimization will have a great effect on holes machining efficiency. Based on the TSP model, an improved hybrid genetic algorithm is proposed to solve holes machining path optimization model to get the optimized processing path. By comparing the path length of the optimized machining path and the simulation time with that obtained using the basic GA and the basic ACO, the optimization algorithm proposed in this paper can effectively reduce the machining path length and thus improve the efficiency of holes machining operation.
Analysis on Influencing Factors of Grinding Aid Effect of Cement Grinding Aids
Authors: Zhao Hui 
Published: February 2021

Abstract
In the cement industry, grinding aids can be used to improve the efficiency, promote the realization of the concept of energy saving and emission reduction, and reduce the production cost to a great extent. Cement grinding aid is a kind of material which can promote cement grinding, and it is an important part of energy-saving development of industry at present. It can not be ignored in improving cement technology. Based on this, this paper analyzes the influencing factors of grinding aid effect in cement grinding process.
The Development Status of Selective Laser Melting Technology (SLM)
Authors: Tian Qiwen 
Published: February 2021

Abstract
With the development of manufacturing technology, traditional manufacturing methods can no longer meet the needs of modern society. Additive manufacturing technology (AM) is a new type, which bases on the principle of layered manufacturing and uses the method of accumulating materials layer by layer to directly manufacture digital models into solid parts. In recent years, AM has been greatly developed and applied. Selective Laser Melting technology (SLM) is a very widely used technology in AM. SLM uses a high-energy laser beam to scan the metal powder on a predetermined path. It first melts the metal powder completely, then after cooling, the melted metal powder solidfies into a part. This article first describes the characteristics and equipment development of SLM technology, then summarizes the application of SLM technology, finally discusses the shortcomings of SLM technology.
Research on 3D Printing Resource cloud Platform Technology based on dynamic Service Composition
Authors: Lv Wenyan 
Published: February 2021

Abstract
To improve the improve the management and matching of 3D printing resources, a 3Dprinting cloud platform based on dynamic service composition technology is established, and the 3D printing composite service is optimized. First, cloud computing is combined with 3D printing to establish cloud manufacturing mode. According to the characteristics of each stage, the dynamic service composition technology under cloud manufacturing mode is divided into three stages. Then, dynamic service composition technology of 3D printing resource is established. Based on the logical relationship between services, breadth algorithm and depth algorithm are used to find the optimal service composition path in the search graph to meet the different needs of users. The experimental results show that the relationship between user requirements and services can be obtained by calculating the quality of service. In the case, the service quality required by users is less than 20, and service 1 and 3 can meet the needs of users. This exploration provides a reference for the study of 3D printing resources dynamic service composition.
Research and Optimization of Inverter Electromagnetic Compatibility System
Authors: Changkai Xia , Xiangli Lin , Chunwei Shao , Mingpeng Ding 
Published: February 2021

Abstract
Modern electrical and electronic equipment has increasingly higher requirements on the reliability of its performance, especially the electromagnetic compatibility of the equipment. According to the working environment of the inverter cabinet and the design requirements of the cabinet, this paper widely combines the practical experience of the project, mainly from the aspects of gaps, ventilation holes, sealing, electrical layout, etc. It puts forward measures to improve the electromagnetic compatibility performance of the cabinet structure design. It achieves the purpose of meeting the requirements of GJB151A, and effectively improves the electromagnetic compatibility of the inverter.
On mechanisms of mixing by forced and natural convection in microfluidic devices
Authors: Bratsun Dmitry , Mizev Alexey , Mosheva Elena , Pismen Len , Siraev Ramil , Shmyrov Andrey 
Published: February 2021

Abstract
Continuous-flow microfluidic devices are applied in the study of microorganisms, in genetic research, production of pharmaceutical substances, lab-on-a-chip technology, biomedicine etc. Some applications require continuous mixing of the solutions that flow through the devices. However, straight-line mechanical mixing methods cannot be used due to the small size of the channels. In this paper, we discuss from a theoretical and experimental point of view the prospects of using various mechanisms of natural or forced convection for efficient mixing of solutions entering a microfluidic chip. Different designs of micromixers operating on gravity-dependent instabilities of the Rayleigh-Taylor type, double diffusion convection, and surface-dependent Marangoni instability are considered. Micromixers, in which the fluid flow is controlled by an electro-osmotic mechanism and directional deformations of the channel walls, are considered as examples of forced convection. For each case, we will provide the assessment of the range of chip sizes in which this mixing mechanism works effectively. The examples of experimental implementation of different mixing principles are given.
Revisiting the need to combine educational and scientific-research processes in teaching CFD modelling to students
Authors: Fedyushkin A I , Puntus A A 
Published: February 2021

Abstract
Using the example of many years of experience in cooperation between Institute No. 8 “Information Technologies and Applied Mathematics” of the Moscow Aviation Institute and Ishlinsky Institute for Problems in Mechanics of RAS points out the need for cooperation between the university and specialists of academic institutions in the preparation of highly qualified specialists in the field of CFD, stages of training, examples of qualification work and the use of software CFD products for training are presented. The difficulties of teaching CFD modeling are discussed, achievements and examples of solving the problems of hydrodynamics and heat and mass transfer by students of the Moscow Aviation Institute are given.
On the effect of reversing the direction of convection in a two-component fluid
Authors: Ingel L Kh 
Published: February 2021

Abstract
The theoretical problem of convection in a two-component medium (for example, in salt water) after “switching on” the sources/sinks of heat and admixture on an infinite vertical boundary is considered. Generally speaking, the degree of influence of the two components on convection is different due to the difference in their diffusion velocities. We suppose that heat diffuses much faster than the admixture and then the heated/cooled region at the lateral boundary is much thicker than the region of propagation of the impurity concentration disturbance. Therefore, convection due to temperature deviations is less affected by viscosity than due to deviations in admixture concentration. As a result, even a relatively weak “thermal” source of buoyancy can determine the direction of convection for some time in spite of the action of a more intense “concentration” source of buoyancy of a different sign. But if a vertical layer of a medium of finite thickness is considered, then a stationary regime is established over time, in which the direction of convection is determined by the total source of buoyancy, so that the direction of convection can change sign.
Diffusion effect on passive solute transport inside an infinite two-dimensional array of vortices
Authors: Maryshev Boris S , Klimenko Lyudmila S 
Published: February 2021

Abstract
The transport process of solute in a two-dimensional liquid flow is studied. The infinite plane is “covered” by square cells with periodic conditions at its boundaries. The flow is provided by a periodic external force. If the amplitude of the external force reaches a certain critical value, then the flow in each cell contains a pair of vortices. The analysis of the transport of a passive solute in such a flow is investigated in terms of a special flow. In the framework of this approach the transport process is described by mapping functions that determine the coordinates of the particle at the end of the unit cell and the time of passage of the cell as a function of the coordinates at the entrance to the cell. These functions are obtained numerically by the random walk method taking diffusion into account. Using the special flow approach the distribution of an initially uniform distributed ensemble of passive particles with time is calculated for the passage of a long array of the unit cells. It is shown that for tiny values of diffusivity the transport slowing down some particles regarding the ensemble is observed. The speed-up of some particles regarding the ensemble is observed for moderate values of diffusivity and for high diffusivity we obtain the standard diffusion.
Concentration-dependent diffusion of lithium, sodium, potassium, and cesium hydroxides in water
Authors: Mizev Alexey I , Shmyrov Andrey V , Mosheva Elena A 
Published: February 2021

Abstract
The diffusion coefficients of aqueous solutions of lithium, sodium, potassium, and cesium hydroxide in a concentration range of 0 to 3.0 mol/L were obtained at 25 °C and normal pressure. The Fizeau interferometer and the spatial phase-shifting method were used to measure the spatial distribution of concentration of the investigated substances. The concentration dependence of the diffusion coefficient was determined from the Matano-Boltzmann analysis. The experimental setup and techniques, as well as the image and data processing procedure, were tested using an aqueous solution of nitric acid. The comparison made for lithium, sodium, and potassium hydroxides indicated good agreement between the obtained results and the data collected from the literature. The concentration dependence of the diffusion coefficient for cesium hydroxide in water was found experimentally for the first time.
Non-axisymmetric flow excited by fluid oscillations in a rotating cylinder with sloping ends
Authors: Subbotin Stanislav 
Published: February 2021

Abstract
Fluid flow in non-uniform rotating (librating) cylinder with sloping ends is experimentally investigated. Periodical changes in the rotation rate lead to the appearance of inertial oscillations of the fluid. Due to the azimuthal inhomogeneity of the geometry of the ends, inertial oscillations are non-axisymmetric. The most intense pulsating motion of the fluid is observed at the frequency corresponding to the mode {1, 1, 1}, which is a global single-vortex flow. As a result of the nonlinear response, a non-axisymmetric steady flow arises along the cavity side wall.
Determination of the stability boundary of a two-layer system of miscible liquids with linear diffusion laws
Authors: Vyatkin Vladimir , Bratsun Dmitry 
Published: February 2021

AbstractThe authors consider the problem of determining the stability boundary of a two-layer system of miscible liquids placed in a gravity field. Liquids are aqueous solutions of non-reacting substances with different diffusion coefficients, which are linear functions of concentrations. At the very beginning of the evolution, the solutions are separated from each other by an infinitely thin horizontal contact surface. Such a configuration can be easily realized experimentally, although it is more difficult for theoretical analysis since the base state of the system is non-stationary. Once brought into contact, the solutions begin to mix penetrating each other and creating conditions for the development of the double-diffusive instability since the initial configuration of the system is assumed to be statically stable. The problem of the convective instability of a mixture includes the equation of motion written in the Darcy and Boussinesq approximations, the continuity equation, and two transport equations for the concentrations. We apply the linearization method suggested by Wiedeburg (1890) to find a closed-form solution to the non-stationary base state problem including concentration-dependent diffusion laws for species. We derive analytical expressions for neutral stability curves and study corrections introduced by nonlinear diffusion to the stability analysis.
Experimental study of liquid-liquid interface oscillating in radial hele-shaw cell
Authors: Karpunin Ivan E , Kozlov Nikolai V , Kozlov Viktor G 
Published: February 2021

Abstract
The dynamics of the interface between two immiscible liquids with a high viscosity contrast is studied experimentally under steady displacement of interface and periodic variation of the flow rate of the pumped liquid in radial Hele-Shaw cell. Classic Saffman–Taylor instability, which develops when the viscous fluid is monotonously displaced by the inviscid one, is well known. In the present work, the excitation of Saffman–Taylor instability by means of oscillations of the liquid-liquid interface is demonstrated. The interphase boundary performs axisymmetric radial oscillations at small amplitude of oscillations and in the absence of an average pumping. With the growth of the amplitude of radial oscillations the interface instability is excited, which manifests itself in the development of an azimuthally periodic finger structure during a part of the period. “Finger-like” instability is determined by the relative amplitude of the oscillations of the interphase boundary and under the conditions of the performed experiments depends neither on the oscillation frequency nor on the radial size of the interface.
On dispersion relation for Faraday waves in a near-critical fluid under weightlessness
Authors: Lyubimova T , Ivantsov A , Beysens D 
Published: February 2021

Abstract
One reports experiments and numerical simulations of Faraday waves at the liquid - vapor interface of fluids (typically CO2 and H2) near its critical point when submitted to vibration in a weightlessness environment. It is known that in such a system striation is formed under the action of vibrations. The boundary between the liquid and gas phases is located perpendicular to the direction of vibrations, and a streaky structure in the form of periodic stripes (striations) is formed in the cavity. It is shown that under vibrations of sufficient intensity an instability develops on the striation interface perpendicular to the direction of vibrations, leading to Faraday waves. A theoretical and numerical study of this instability is carried out, the critical parameters of the appearance of Faraday waves are determined taking into account the interaction of waves on adjacent striations. Dispersion relations for Faraday waves are obtained numerically. It is shown that in the vicinity of the critical point there is a significant deviation of the dispersion relation from the classical theoretical dependence.
On the mechanism of selective fixation of bubbles under the action of ultrasound in NaCl and KCl solutions during degassing
Authors: Lyubimova T P , Rybkin K A , Fattalov O O , Kuchinskiy M O , Kozlov M V , Kugaevskaya A A 
Published: February 2021

Abstract
This paper describes the experimental study of the mechanism of selective fixation of bubbles formed in a liquid under the influence of ultrasound on the surface of plates of various degrees of wettability when the liquid is degassed as a result of ultrasonic action. The experiments used solutions of NaCl and KCl of various concentrations, as well as distilled water. The plates are made of organic glass (wetting angle 51°) and Teflon (wetting angle 118°). As a result of the study, the experimental data on the surface area occupied by bubbles on the surface of plates were obtained, and the mechanism of selective fixation of bubbles under the influence of ultrasound in the conditions of emerging degassing was shown.
Buoyancy-driven instabilities induced by a neutralization reaction in immiscible fluids
Authors: Mizev Aleksey , Shmyrova Anastasia 
Published: February 2021

Abstract
Buoyancy-driven instabilities triggered by neutralization reaction in an immiscible two-layer system placed in a vertically oriented narrow cell were studied experimentally. The initial density of the layers was always set to exclude the development of the Rayleigh-Taylor instability. The problem was examined for the surface-inactive species, namely hydrochloric acid and sodium hydroxide, which allowed studying a convective instability development solely due to buoyancy-driven mechanisms, excluding Marangoni effects. We show that one of two global scenarios develops in the system right after the layers came into contact. These scenarios, called by us diffusion-controlled and convection-controlled, essentially differ in the prevailing mechanism of mass transfer and, therefore, in the rate of reaction-diffusion-convection processes. The authors introduce the nondimensional parameter, the value of which determines the border between the two scenarios in the regime map.
Blow-up singular dynamics in breast cancer metabolism
Authors: Rogotnev A , Nikitiuk A , Bayandin Yu , Naimark O 
Published: February 2021

AbstractCancer cells have an altered metabolism, which results in specific kinetics of the heat localization and coherent pattern formation. Modified nonlinear Pennes equation was used for the modeling of the metabolic temperature dynamics. The numerical experiments were conducted in order to identify the tissue metabolic reactions in terms of multiscale correlation parameters (spatial invariants) as the characteristics of globally convergent dynamics of blow-up collective modes and the cancer precursor.
Effect of rotation on thermal convection in horizontal plane layer subject to circular vibration
Authors: Rysin Kirill , Kozlov Victor , Vjatkin Alexei 
Published: February 2021

Abstract
The stability of quasi-equilibrium of a horizontal liquid plane layer with isothermal boundaries of different temperatures, subject to circular vibrations in the horizontal plane, is experimentally studied. The rotation of the cavity around the vertical axis is set independently. In order to exclude from consideration the destabilizing effect of the gravity field, the layer is heated from the top. In the absence of rotation, the circular vibrations lead to the threshold excitation of vibrational thermal convection in the layer of nonisothermal liquid, in spite of its stable stratified in the gravity field. At given vibration amplitude and temperature difference at the layer boundaries, the threshold is determined by sharp increase in heat transfer with a monotonic increase in the vibration frequency. The size of the convective spatial structures is determined by the layer thickness. In the case of high-frequency vibrations, convection is determined by dimensionless parameters: gravitational Rayleigh number Ra
and vibrational parameter R
v. The thresholds of vibrational convection excitation on the plane of these parameters in the case of circular vibrations coincide with the theoretically predicted stability boundary for linear vibrations. It is shown that rotation has a stabilizing effect on vibroconvective stability, similar to the case of gravitational convection. The threshold value of the vibration parameter R
v grows with an increase in the dimensionless rotation velocity ω
rot. Under conditions of the performed experiment, the structure of convective cells and the wave number of structures in the supercritical region do not change in comparison with ω
rot = 0.
Stirring of liquid metal in electrovortex flow in a hemispherical volume under the influence of external magnetic field
Authors: Vinogradov D , Teplyakov I , Ivochkin Yu 
Published: February 2021

Abstract
The results of calculations of the stirring rate of liquid metal in a system simulating a DC arc furnace are presented. The equations of motion and transfer of impurity were solved for the electric vortex flow of a liquid metal between two hemispherical electrodes under the influence of an external axial magnetic field. The quality of mixing was characterized by the deviation of the impurity concentration from the mean and was calculated at each time step. It is shown that the effect of an external magnetic field can both accelerate and slow down mixing. These results can be used in electrometallurgy to assess the effectiveness of electromagnetic stirring.
Effect of laser surface modification on the hardness and wear resistance of structural bearing steel for roller screw mechanism
Authors: Zhdanov A.V. , Belyaev I.V. , Morozov V.V. 
Published: February 2021

Abstract
The article is devoted to the analysis of the effect of laser surface modification on the hardness and wear resistance of steel SHX15SG used in the manufacture of roller screw mechanisms. Experiments on laser surface modification were performed on the Russian domestic SVAROG-1-5DR laser system. to get the maximum hardness value. When laser processing without melting the surface of steel SHX15SG, the laser radiation power should be in the region of 5 kW, which corresponds to the maximum power for the installation used. The speed of movement of the laser beam relative to the treated surface should be equal to 25 mm/s, and the focal length should be at least 60 mm. In the case of laser treatment with surface reflow, higher hardness values are obtained at a power of 2 kW. Increasing the power of laser radiation to 5 kW leads to a decrease in hardness. In this case, the speed value should be equal to 25 mm/s, and the focal length should be close to 85 mm. When the focal length is reduced to 60 mm, laser treatment no longer causes melting of the surface of the material under study.
Structural and scattering characteristics model of a fractal nanoclustered island Ag-Au films
Authors: Bukharov D.N. , Novikova O.A. , Essaka S.P.Eyoum , Arakelian S.M. 
Published: February 2021

Abstract
Samples of Ag/Au nanocluster/island fractal nanofilms obtained by thermal diffusion deposition from a colloidal solution are presented. Modeling and evaluation of the features of their structure in the approximation of diffusion-limited aggregation are carried out. The evaluation of the scattering characteristics of the study on the model samples in the framework of the Fischer-Burford relation is made.