bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of the “monopole” instability in the evolution of two-dimensional turbulent free shear layers
Authors: Suryanarayanan Saikishan , Brown Garry L. , Narasimha Roddam
Published: November 2020

The role of instability in the growth of a two-dimensional, temporally evolving, “turbulent” free shear layer is analyzed using vortex-gas simulations that condense all dynamics into the kinematics of the Biot–Savart relation. The initial evolution of perturbations in a constant vorticity layer is found to be in accurate agreement with the linear stability theory of Rayleigh. There is then a stage of non-universal evolution of coherent structures that is closely approximated not by Rayleigh stability theory, but by the Karman–Rubach–Lamb linear instability of monopoles, until the neighboring coherent structures merge. After several mergers, the layer evolves eventually to a self-preserving reverse cascade, characterized by a universal spread rate found by Suryanarayanan, Narasimha, and Hari Dass [“Free turbulent shear layer in a point vortex gas as a problem in nonequilibrium statistical mechanics,” Phys. Rev. E 89, 013009 (2014)] and a universal value of the ratio of dominant spacing of structures (Λf) to the layer thickness (δω). In this universal, self-preserving state, the local amplification of perturbation amplitudes is accurately predicted by Rayleigh theory for the locally existing “base” flow. The model of Morris, Giridharan, and Lilley [“On the turbulent mixing of compressible free shear layers,” Proc. R. Soc. London, Ser. A 431, 219–243 (1990)], which computes the growth of the layer by balancing the energy lost by the mean flow with the energy gain of the perturbation modes (computed from an application of Rayleigh theory), is shown, however, to provide a non-universal asymptotic state with initial condition dependent spread rate and spectra. The reason is that the predictions of the Rayleigh instability, for a flow regime with coherent structures, are valid only at the special value of Λf/δω achieved in the universal self-preserving state.
The preferential growth behaviors of the intermetallics at the W/Co interface during spark plasma sintering
Authors: Deng Shenghua , Li Ruidi , Yuan Tiechui , Yang Pan , Xie Siyao , Li Jianan
Published: November 2020

The strong electric current in spark plasma sintering (SPS) often gives sintered materials unique microstructures. In the present study, it is found that the Co3W grains formed at the W/Co bonding interface preferentially grow along [21¯1¯0] (or its equivalent orientations) in the current direction during SPS, which is significantly different from that without current. We propose that the resistance anisotropy of grains under electromigration leads to anisotropic atomic diffusion, inducing the preferential growth of grains under current. This work may provide an approach and a theoretical foundation for the preparation of materials exhibiting directional growth.
La red polisémica denegro
Authors: Soto Nieto Almudena
Published: November 2020

El principal objetivo del artículo es describir el carácter polisémico del término cromático españolnegroy presentar esta unidad léxica como una categoría radial constituida por diferentes sentidos relacionados entre sí, así como también destacar el papel protagonista de la metonimia tanto en la motivación como en la conexión de los sentidos. El estudio se estructura de la siguiente manera: (i) exposición de las principales características de la semántica cognitiva y su concepción de la polisemia (ii) descripción de la motivación de cada una de las extensiones semánticas asociadas al término cromático, y (iii) trazado de la red radial del términonegroque lo estructura como categoría polisémica y presentación de la relación que se establece entre ellas a partir de la metonimia y la metáfora. Para llevar a cabo la investigación se ha aplicado una metodología basada en corpus que permite obtener muestras de uso real del término cromático, así como acceder a la información lingüística y contextual que interviene en la activación y distinción de sentidos. En cuanto a la motivación y relación entre ellos, el estudio se realiza de acuerdo a la TCMM.
Mechanosensitive collaboration between integrins and connexins allows nutrient and antioxidant transport into the lens
Authors: Liu Jie , Riquelme Manuel A. , Li Zhen , Li Yuting , Tong Yuxin , Quan Yumeng , Pei Cheng , Gu Sumin , Jiang Jean X.
Published: November 2020

The delivery of glucose and antioxidants is vital to maintain homeostasis and lens transparency. Here, we report a new mechanism whereby mechanically activated connexin (Cx) hemichannels serve as a transport portal for delivering glucose and glutathione (GSH). Integrin α6β1 in outer cortical lens fiber activated by fluid flow shear stress (FFSS) induced opening of hemichannels. Inhibition of α6 activation prevented hemichannel opening as well as glucose and GSH uptake. The activation of integrin β1, a heterodimeric partner of α6 in the absence of FFSS, increased Cx50 hemichannel opening. Hemichannel activation by FFSS depended on the interaction of integrin α6 and Cx50 C-terminal domain. Moreover, hemichannels in nuclear fiber were unresponsive owing to Cx50 truncation. Taken together, these results show that mechanically activated α6β1 integrin in outer cortical lens fibers leads to opening of hemichannels, which transport glucose and GSH into cortical lens fibers. This study unveils a new transport mechanism that maintains metabolic and antioxidative function of the lens.
Machine learning-based off-line electrical characteristic prediction through in-line pattern integrity inspection
Authors: Liu Ting-Jeng , Wu Meng-Jhu , Lo Cheng-Yao
Published: November 2020

In this study, an image inspection method was introduced to two-arm Archimedean spiral antenna patterns to quantify and qualify their in-line integrity, which was linked to their off-line electrical characteristics in terms of the capacitance values through machine learning. The pattern was intentionally deteriorated in shape to imitate potential fabrication variations existing in the microelectronic production line, and six physical features including the inner line edge roughness (LER), outer LER, integrated LER, inner arm length, outer arm length, and arm area were collected. Two groups of training and testing samples were simulated and fabricated. Based on Gaussian process regression with the covariance function in the form of a squared exponential, a model was developed to predict the capacitance values from the performances of the six features. The accuracy of the developed model was evaluated using the coefficient of determination and root-mean-square error. The results indicate that the developed model is capable of predicting the off-line electrical characteristics of microelectronic components based on their in-line pattern integrities. Advanced studies also reveal that although all LER values and arm lengths contribute to the electrical characteristics, the arm area is decisive.
Propagation of ultrasonic guided waves in plant leaves
Authors: Collazos-Burbano D A , Ealo Cuello J L , Villagrán-Muniz M
Published: November 2020

In this work, dispersive wave propagation in plant leaves is studied using a long distance laser-based ultrasonic method. Guided waves traveling through and along the midrib, as well as in the lamina, are measured and analyzed via wave attenuation, characteristic diagram and dispersion curves. Additionally, an estimation of the leaf elastic properties using the Rayleigh–Lamb model, supported by thickness-resonance frequency constraints, is proposed. This study paves the way for the development of acoustic fingerprints for the identification of leaves and their non-invasive and fairly non-destructive mechanical characterization, which is highly related to the plant hydraulics and photosynthetic activity.
Numerical investigation on the influence of circuit breaker structure parameters on vacuum arc behaviors
Authors: Zhao Lihua , Gou Hangyuan , Yang Mengjie , Hong Guo , Bai Xueyan , Huang Xiaolong , Ren Junwen , Ning Wenjun , Wang Lijun
Published: November 2020

In a switchgear, an external transverse magnetic field (ETMF) is generated by the U type loop consisting of the vacuum interrupter, external busbar and conductive rod connected to the vacuum interrupter. The ETMF will make the vacuum arc deflected and strengthen the contraction of the arc. This can increase the probability of breaking failure. To weaken the adverse effect of the ETMF, the real magnetic field data of the arc area with different structure parameters when the length of conductive rod, external busbar and phase distance is changed are obtained by establishing simulation model in this paper. Taking the real magnetic field data as the boundary condition, this paper obtains the typical parameters of the vacuum arc plasma with different structure parameters by using the established three-dimensional high-current vacuum arc magnetohydrodynamics model. The simulation results show that the ETMF makes the transverse magnetic field (TMF) of the arc area asymmetric, which leads to an arc deflection. Reducing the length of the conductive rod connected to the vacuum interrupter to 50 mm can effectively improve the asymmetry of the TMF caused by the EMTF, weaken the arc deflection phenomenon, make the distribution of the plasma parameters more uniform, and increases the utilization of the anode contact surface. Moreover, it can not only reduce the heat flux density into the anode as a whole, but also reduce the heat flux density in the high heat flux density area, so as to effectively reduce the degree of anode activity and improve the negative effects caused by the anode activity. The changes of other external structural parameters have less influence on the improvement of the vacuum arc deflection phenomenon. Increasing the phase spacing to 275 mm or reducing the length of the external bus bar to 100 mm can only slightly weaken the arc deflection.
A thermal-insensitive ultra-broadband metamaterial absorber
Authors: Bai Ningfeng , Zhong Fuxian , Shen Jingxuan , Fan Hehong , Sun Xiaohan
Published: November 2020

In this paper, a thermal-insensitive ultra-broadband metamaterial absorber (MMA) based on indium tin oxide (ITO) patterns and the SiO2 dielectric substrate is proposed to demonstrate high-temperature stability and excellent absorbability. The surface patterns consist of two different sizes of rectangular split-ring resonators with two gaps in each split-ring. Results from simulation indicate that at the initial temperature of 300 K, the relative absorption bandwidth reaches 83.35%, and the spectrum with absorptivity higher than 90% ranges from 8.00 GHz to 19.43 GHz. Moreover, in the temperature range of 300–700 K, the effective bands remain steady and cover more than 95% of the initial band. The simulation results also verify that the performance of MMA remains stable when exposed to high-intensity incident and high temperature of 500 K. The analysis of the surface current, electromagnetic (EM) field, power-loss density, equivalent circuit, and constitutive EM parameters reveals the mechanisms of thermal-insensitive ultra-broadband. This study expands potential applications of MMAs in conditions with thermal-stable demands.
Excited states in hydrogenated single-layer MoS2
Authors: Din Naseem Ud , Turkowski Volodymyr , Rahman Talat S
Published: November 2020

Our calculations of the excitation spectrum of single-layer MoS2 at several hydrogen coverages, using a density-matrix based time-dependent density-functional theory (TDDFT) show that the fully hydrogenated system is metallic, while at lower coverages the spectrum consists of spin-polarized partially filled localized mid-gap states. The calculated absorption spectrum of the system reveals standard excitonic peaks corresponding to the bound valence-band hole and conduction-band electron, as well as excitonic peaks that involve the mid-gap states. Binding energies of the excitons of the hydrogenated system are found to be relatively large (few tens of meV), making their experimental detection facile and suggesting hydrogenation as a knob for tuning the optical properties of single-layer MoS2. Importantly, we find hydrogenation to suppress visible light photoluminescence, in agreement with experimental observations. In contrast, both Li and Na atoms transform the system into an n-doped non-magnetic semiconductor that does not allow excitonic states.
Non-Hermitian generalizations of extended Su–Schrieffer–Heeger models
Authors: He Yan , Chien Chih-Chun
Published: November 2020

Non-Hermitian generalizations of the Su–Schrieffer–Heeger (SSH) models with higher periods of the hopping coefficients, called the SSH3 and SSH4 models, are analyzed. The conventional construction of the winding number fails for the Hermitian SSH3 model, but the non-Hermitian generalization leads to a topological system due to a point gap on the complex plane. The non-Hermitian SSH3 model thus has a winding number and exhibits the non-Hermitian skin effect. Moreover, the SSH3 model has two types of localized states and a zero-energy state associated with special symmetries. The total Zak phase of the SSH3 model exhibits quantization, and its finite value indicates coexistence of the two types of localized states. Meanwhile, the SSH4 model resembles the SSH model, and its non-Hermitian generalization also exhibits the non-Hermitian skin effect. A careful analysis of the non-Hermitian SSH4 model with different boundary conditions shows the bulk-boundary correspondence is restored with the help of the generalized Brillouin zone or the real-space winding number. The physics of the non-Hermitian SSH3 and SSH4 models may be tested in various simulators.
Numerical approach to optimizing the doping concentration of the absorber layer to enhance the performance of a CdTe solar cell
Authors: Sameera Jannatun Noor , Jhuma Farjana Akter , Rashid Mohammad Junaebur
Published: November 2020

Cadmium telluride (CdTe)-based solar cells have been proving their potential for high efficiency performance for several decades. However, efficient p-type doping of CdTe has remained a critical challenge for decades thus limiting the performance of this type of solar cell. Thus, this work intends to assess the effects of various dopants and their optimization in order to obtain efficient photovoltaic (PV) performances. In the process we used numerical simulation software SCAPS-1D as it expedites and facilitates the modeling of a solar cell through optimizations and variations. The studied CdTe solar cell structure comprises multi-junction semiconductor layers such as n-ITO/n-ZnO/n-CdS/p-CdTe in a superstrate structure. Three different types of absorber layer dopants such as copper (Cu), silver (Ag) and arsenic (As) are used, respectively. The work started with the optimization of carrier concentration followed by the variation of the thickness of the absorber layer. The PV performances in terms of open-circuit voltage, short-circuit current density, fill factor and efficiency are presented and, after comparison, the As dopant is shown to be a promising candidate. Also, the working temperature is varied to obtain a suitable environment under which the solar cell can work efficiently.
A magneto-active soft gripper with adaptive and controllable motion
Authors: Li Xianghao , Zhang Zheng , Sun Min , Wu Helong , Zhou Yisong , Wu Huaping , Jiang Shaofei
Published: November 2020

Bionic soft grippers that can gently conform to the objects of any profiles and softly hold them with uniform pressure have been receiving considerable attention. To realize rapid and non-contact driving, a novel magneto-active soft gripper is developed in this paper. The gripper is embedded with magneto-active elastomer (MAE) actuators that are made from a mixture of a soft material substrate and hard magnetic fillers. Firstly, the MAE actuators doped with different contents of magnetic fillers are manufactured and magnetized by applying an external magnetic field. An experiment is designed to measure the magnetically induced deformation of MAE actuators under different external magnetic fields. On basis of the experimental study of MAE actuators, the magneto-active soft gripper is then designed and successfully fabricated. The gripping function and efficiency of the magneto-active soft gripper is demonstrated through an experimental study. Meanwhile, the maximum gripping force of grippers is measured and the effects of applied magnetic field and mass faction of magnetic fillers are examined. It is found that the gripping force increases as either magnetic field strength or magnetic fillers’ concentration increases but tends to be stable when the magnetic field is greater than 80 mT. When executing a gripping motion, the magneto-active soft gripper has a significantly short response time than the existing ones with other driving methods.
Quantum dynamics of vibrational energy flow in oscillator chains driven by anharmonic interactions
Authors: Borrelli Raffaele , Gelin Maxim F
Published: November 2020

A new model of vibrational energy transfer in molecular systems taking into account anharmonic (third order) interactions of localized vibrations with a chain of harmonic oscillators is developed. The role of the energy spectrum of the chain and of the magnitude of the non-linear coupling is discussed in detail by an exact numerical solution of the quantum dynamical problem based on the tensor-train (matrix product state) representation of the vibrational wave function. Results show that the type of wave packet motion is determined by the eigen-spectrum of the chain and by its excitation time. It is found that when the excitation of the chain takes place on a much shorter timescale than the energy transfer along the chain the vibrational wave packet moves in a ballistic way independently of the length of the chain. On the other hand when the excitation of the chain takes place on the timescale of the energy transfer along the chain the overall motion becomes superballistic. These findings shed new light on recent observations of ballistic energy transfer along polymethylene chains.
Application of Kalman filter for prevention of unrequired operation of power transformer differential protection
Authors: Ivanchenko D I , Belsky A A , Dobush V S
Published: November 2020

As power transformers are core elements of electric power supply systems, transformer protection systems must reach high requirements. In order to reduce possible damage to transformers and prevent cases of false operations, resulting in interruptions of technological processes, protection devises with high sensitivity and high speed are required. This paper represents implementation of Kaman filtering theory with reduced calculation time for identification of faults in transformer from other transients. Parameters for tuning of Kalman filter for protection task and identification criteria were established. Operation of proposed algorithm was experimentally compared to Fourier transform based algorithm.
Research on acid and high-mineralized wastewater neutralization and purification process of the thermal power plant (TPP) ionite water treatment plants on laboratory stand
Authors: Yu Vlasova A , Vlasov S M
Published: November 2020

This paper presents the laboratory setup model for a treatment of acid sulfate-containing wastewater after regeneration of TPP water treatment plant (WTP) H-cation exchange filters. The model is based on the principle of acid wastewater neutralizing by alkaline slurry with further calcium chloride co-precipitation, which is the main component of highly mineralized TTPs wastewater. The wastewater slurry components analysis revealed that it consists of 80% calcium carbonate.
Approximation of hydraulic turbine performance characteristics using optimal splines and neural networks
Authors: Kovartsev Alexander , Nazarova Anastasia , Zakharchenko Vitaliy
Published: November 2020

The performance characteristic of hydrounits is used very often in various control systems on hydro power plant for velocity control, power distribution, for displaying at different levels of automation pyramid: technicians, technologists, management and so on. Different systems do not have single unified description of the hydrounit’s performance characteristic. It leads to growth of unnecessary calculations, errors and collisions. The study of the turbine efficiency can be automated by creating an appropriate mathematical model that approximates the initial performance characteristics of the turbine. This paper describes a method of approximation of the turbine performance characteristics using optimal two-dimensional cubic Hermit splines with free boundary conditions. The proposed method of hydrounit efficiency description allows to create single mathematical model and to use it in any control systems. The calculation load tests show high efficiency of the methods and confirm the possibility of their application in PLCs and servers.
FT-IR in situ thermoelectrochemical cell for electrode kinetics study
Authors: Kiselev N V , Artyukhov D I , Gorshkov N V , Burmistrov I N
Published: November 2020

The main parameter, that determines the use of thermoelectrochemical converters (TECC) for the waste heat harvesting is the efficiency of thermoelectric conversion. An increase of the current density at the electrode is possible due to the use of heterogeneous redox catalysts. In this paper, early results of Ti-based mineral catalysts usage are presented. A new type of thermoelectrochemical cell for in situ FTIR spectroscopy was designed, assembled and tested. With its use, the pattern of the redox reaction in

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Installation of wind turbines on the smoke stacks of power facilities
Authors: Ilyin R A , Shishkin N D
Published: November 2020

Currently, many works are devoted to the development of modern designs of wind power plants and improving the efficiency of existing ones. The work considered the issue of using wind energy by wind power plants, which are proposed to be installed on the chimneys of energy facilities. The original design of such an installation has been developed, which will allow using the phenomenon of free convection for its work even in the absence of an oncoming wind flow. The operation of the plant will partially or completely cover the costs of its own needs of the energy facility during its operation, which includes chimneys.
Interaction of temperature fields in an unlimited array of soil during the selection of low-grade heat by U-shaped probes of a geothermal heat pump units
Authors: Semenov B A , Saponenko D S , Dolotovsky I V , Pashchenko D I
Published: November 2020

The methodology and results of mathematical modeling of the unsteady process of selecting low-grade soil heat with a vertical U-shaped geothermal probe placed in a well of heat pump units (HPU), the free space of which is filled with a heat-conducting filler, are presented. The developed mathematical model is based on the joint use of two classical analytical methods: a source-drain adapted to the unsteady process of heat extraction from an unlimited soil mass, and a superposition method that allows one to quantify the effect of the interaction of the temperature fields of the downpipe and the riser pipe laid at a small distance from each other in one well. As a result, the main calculated dependencies underlying the developed mathematical model on which the computational experiment was performed were obtained analytically. The results of a computational experiment, performed on the example of a well with a vertical U-shaped soil probe, designed to select low-grade heat from an unlimited array of dry sand, are presented in graphs. An analysis of the results made it possible to identify the main factors affecting the intensity of heat extraction, justify the conditions for the effective operation of U-shaped probes in the wells of the soil contour of heat pump units, and quantitatively determine the maximum allowable temperature increment of the heated coolant according to the condition of efficient use of the heat transfer surface.
Development of a method for wireless information transmission in wells equipped with sucker rod pump units
Authors: Galeev A S , Arslanov R I , Suleymanov R N , Filimonov O V
Published: November 2020

Oil lifting via sucker rod pump units is the most widespread way to extract oil reservoir products. Complications adversely affecting the operation of downhole equipment and entailing increased wear and premature failure of sucker rod pump units arise in the process of high-viscosity oil production. The pressure and temperature of the well fluid are the main parameters for assessing changes in the properties of the extracted products and for determining the static level of the liquid column. It is possible to control pressure and temperature using sensors located in the immediate vicinity of the well pump. Today, a wired channel is the main way of transmitting the measured data to the well mouth. The present work proposes a new technical solution for a wireless communication channel along tubing strings and rods. The columns are separated by asphaltenes deposits on the surface of the columns and centralizers mounted on the rods. The rod string isolation from the tubing string at the wellhead is carried out through suspension modernization. Columns are closed inside the pump, specifically, on the cylinder-plunger contact. Information is transmitted from the bottom by means of a submersible module, consisting of an electrical separator and electronic circuit. The latter controls the separator closure and opening. The results of measurements of the resistance between the columns indicate the possibility of implementing a communication channel.
Information security management of enterprise mobile device
Authors: Omelchenko T A , Nikishova A V , Umnitsyn M Yu , Omelchenko I A , Umnitsyn Yu P
Published: November 2020

The development of the modern labour market involves increasing the level of mobility of personnel, so the current trend is the spread of mobile devices in the implementation of professional activities. This practice improves the efficiency of enterprise, but also has a negative impact on the security of information systems of enterprises. The growing requirements of employers have led to the growth of the functionality of mobile devices. However, this also causes an increase in the number of vulnerabilities in them, leading to an increase in the complexity of the security processes. The combination of the above problems determines the need to organize the process of information security management of enterprise mobile devices. The model of information security management of enterprise mobile devices is described in the article. It allows identifying vulnerabilities of operating system objects of enterprise mobile devices by modelling combinations of dangerous permissions more accurately.
An algorithm for selection of the preferable root switch for the spanning-tree protocol in computer networks
Authors: Rahman P A
Published: November 2020

This scientific paper deals with the computer networks based on the Ethernet technology and Spanning Tree Protocol (STP), as well as with the problem of selection of the root switch for the STP. The author offers an algorithm for selection of the preferable root switch for the STP based on the Floyd-Warshall algorithm for calculation of the shortest paths between all pairs of switches in a computer network. The algorithm for calculation of tree of the shortest paths for the given root switch is also overviewed. Finally, an example of the selection of the preferable root switch for the given network and calculation of tree of the shortest paths for the selected root switch is also presented.
Gesture identification in testing mode in the integrated sign language training system
Authors: Grif M G , Lukoyanychev A V
Published: November 2020

The structure of an integral sign language teaching system based on a 3D computer character, which allows demonstrating fingerprints and words of a sign language using an avatar, is considered. The system provides the test mode when the user must demonstrate the word or fingerprint indicated by the system. The user feedback with the system is carried out using a standard webcam. The problems of gesture localization and identification in user testing mode are considered. The features of this mode are determined during the system operation. The algorithm for quick identification of human hand gestures is proposed. The method based on the signs, which are two-dimensional projections, is used for gesture identification. The projection recognition features are considered, the similarity metrics are analyzed, and three stages for match decision are identified. The experimental results show the stable operation of this algorithm in various lighting conditions and at the place where the gesture was shown.
The method for predicting self-collisions of multi-link manipulators
Authors: Kramar VA
Published: November 2020

The article proposes a method for solving the problem of predicting the self-collision of multi-link manipulators with their agreed work. The method is based on the analysis of projections of manipulator links on coordinate planes. The proposed approach will make it possible to solve the problem simple and suitable for the online prediction mode of critical positions of manipulators, possible self-collision, with their coordinated work. The developed algorithm was tested when constructing the control of an anthropomorphic robot SAR-400.
Analysis of mechanisms of using the concept of probabilities to model plausible reasoning in technical diagnostics
Authors: Litvinov E S , Daneev A V , Stepanenko D A , Stepanenko A S
Published: November 2020

Automated systems of support and decision making (ASDS), using knowledge bases, containing expert opinions of leading specialists in a certain type of expertise, can render great assistance in decision-making. Such intellectualized systems can be effective, in particular, in the work of a criminal investigator and conduct forensic examinations. A criminal expert is obliged not only to report his conclusion, he must justify it and at the same time, so that the investigator or the court could understand and assess whether this conclusion is correct. In order to address issues related to the improvement of forensic analysis, it is necessary to have, above all, appropriate information support. The following paper offered a number of specialized applied problems in the field of technical diagnostics, the received results can be used for intellectual support of a substantiation and decision-making also concerning questions of investigation of separate kinds of crimes or carrying out of other kinds of forensic analyses.
Mathematical model of the technological vibratory unit with electromagnetic excitation
Authors: Neyman L A , Neyman V Yu , Markov A V
Published: November 2020

The mathematical model of the technological vibratory unit with electromagnetic excitation is considered to its features that are important for the dynamic design problems. The model is based on the differential equations of electrical balance and mechanical balance, taking into account the mobility degree of inertial masses with spring linkages. The vibratory unit vibration properties are analyzed concerning the power voltage and frequency coupling, interacting inertia masses mobility degree, spring linkages properties, magnetic core steel magnetizing characteristic non-linearity, leakage fluxes, electric, magnetic and mechanical energy losses. The research performed for dynamical design problem solution is distinguished by a novel approach to the estimation of the capability of changing vibration properties of the movable operating element of the technological vibratory unit with an additional mass attached to it. The model design technology based on the structural modelling method supported by Matlab Simulink is proposed. The research results can be useful for specialists in vibration engineering, machines and devices durability dynamics and vibroprotection.
Computer modeling of rock massif stress condition for mining planning on overworked seam
Authors: Sidorenko A A , Ivanov V V , Sidorenko S A
Published: November 2020

The paper presents the results of computer modeling using the finite-element method of rock massif stress condition during the development of overworked coal seams 69 and 70 in the conditions of Taldinskaya-Zapadnaya-2 mine (Kuznetsk Coal Basin, Russia). The performed studies made it possible to obtain the distributions of stress fields around the walls in the rock massif and stress profiles, as well as stress concentrations in overworking and overworked seams. The study shows the need to consider the increased stresses from the pillars in the conditions of Taldinskaya-Zapadnaya-2 mine. It gives recommendations for the arrangement of coal roadways in seam 69 beyond the limits of increased stress zones – in discharge zones.
Estimating the distribution density function using a DOG wavelet
Authors: Timofeev V S , Isaeva E V
Published: November 2020

It is often necessary to obtain information on the distribution form of a random variable within the framework of statistical data analysis. There are several ways of estimating probability density distributions. Wavelet density estimators distribution of a random variable, built with DOG wavelet, would be considered. Three methods are proposed for determining the normalizing parameter, which provides a correction for the non-orthogonality of the DOG wavelet. In addition, studies have been carried out on the impact on quality wavelet estimates of parameters such as sample size, a number of coefficients of expansion, a function by series in the expression for wavelet density estimates. In the course of this process, it was noted that the quality of estimates on the smoothing parameter is substantial. Moreover, there is its best meaning. The conclusion is made that the estimate is based on DOG wavelet, provides quality recovery density functions.
Agent-based approach to modeling the process of viral marketing
Authors: Utakaeva I H
Published: November 2020

The space of social networks and the Internet challenge classic marketing tools and offers new, modern, effective technologies that improve consumer value. The high rate of technology change poses the problem of effective marketing. In the context of digitalization, new technologies are rapidly forming new market platforms and ways to satisfy their requirements. In this regard, marketers are forced to constantly upgrade their tools and approaches. One effective approach to improving consumer demand is viral marketing. In a highly competitive environment, many more companies are resorting to the viral marketing apparatus. Viral marketing can be based on sound marketing principles, but at the same time become a dangerous tool. Classical epidemic spread models do not take into account the features of modern viral marketing technologies and social networks. The article discusses the concept of viral marketing as a modern tool to increase the consumer value of goods and services. The advantages and disadvantages of this advertising tool are revealed. The main stages of building a viral campaign are described. The conditions under which viral marketing is developing successfully are identified. An agent-graph model of the spread of viral information based on the epidemiological approach that takes into account the basic principles of interaction in a social network is built.
Mathematical modelling of the cryogenic-dynamic start-up process in a pneumatic installation
Authors: Yerezhep D , Aldiyarov A , Sokolov D , Nurmukan A , Krutskikh B , Amangeldieva Zh
Published: November 2020

For studying the kinetic laws of the processes of transitional phase processes of cryo-liquids into the vapor phase, methods of mathematical modelling were used. A mathematical model was developed for the instant boiling up of cryo-liquids using the finite element method. The paper shows the results of a numerical experiment with different amounts of evaporating cryo-liquid in the same temperature range. The dependences of Von Mises pressure and pressure during cryo-liquid evaporation are shown. These studies are necessary for further detailed study of the kinetic laws of the processes of fast-flow phase transitions of cryo-liquids in a pneumatic installation for the cryogenic-dynamic startup of devices.
Problems of using neural networks
Authors: Mikheev M Yu , Gusynina Yu S , Shornikova T A
Published: November 2020

Currently, the urgent task is to develop new algorithms for identifying and diagnosing technical objects. Often artificial neural networks are used in solving such problems. In these tasks, most often, there is no setting the task in an explicit formal form to describe objects and phenomena, and neural networks do well in this case to solve them. The article considers various existing approaches of identification of objects based on neural networks, as well as diagnostics of technical objects based on artificial neural networks. A vision of the prospects for further development of such tasks is offered. Various methods for training the network in the case of problems of identification and diagnosis of faults are described. The task of identifying technical objects is reduced to the task of approximating data, and the task of diagnosing the state of the system to the task of recognizing images. The algorithms for selecting the optimal network structure are investigated. The advantage of using software and hardware technologies in the construction of neural network algorithms has been evaluated. The results of the article can be used in constructing a scheme of actions of identification and diagnostics of technical objects using artificial neural networks.
Second-order aperiodic link modelling with the use of Siemens programmable logical controller SCL hardware
Authors: Urasov D , Cherniy S , Bazhenov R , Alekseeva L , Korosteleva I
Published: November 2020

The paper focuses on the features of modelling the elements of control systems using non-standard tools, in particular, based on the resources provided by industrial logic controllers. The authors point out the features of implementing such models, the control program for an industrial logical controller, as well as the forwarding algorithm for control data to regular simulation modelling tools. A comparative study of the obtained properties with models built in the environment of engineering computing proved to be appropriate to use such hardware and software to solve problems of that kind.
Electric machine with combined excitation in transport
Authors: Kaluzhsky D L , Biryukov V V , Mekhtiyev A D , Alkina A D
Published: November 2020

One of the factors of the electric rolling stock competitiveness of any type of transport is the amount of energy consumed by its electric drive for transporting passengers. During movement, most of the energy is consumed as a heat energy loss in electric traction machines. It is especially important to reduce energy losses in the drive of vehicles with an autonomous power plant. In order to reduce losses in the mechanical part of drives and to increase reliability of their work, it is advisable to use an individual electric drive for each wheel of the rolling stock running gear, especially rail vehicles. In the electrical part of the drive, most of the energy loss is due to the traction motor. Electric motors with the rigid electromechanical characteristic are known to be most suitable for electric traction. These include electric machines with a combined excitation system, which can significantly increase their efficiency and reduce energy consumption by regulating the magnetic field of the machines. The article discusses one of the options of this kind of machines.
Investigation of possible paths to implement the planar 3RPR robot movement along a predetermined trajectory
Authors: Kuzmina V S , Malyshev D I , Gaponenko E V , Khalapyan S Y , Rybak L A
Published: November 2020

The paper considers various possibilities for implementing the movement of a robot of the parallel structure along a pre-calculated trajectory. A computational experiment using a model of a planar 3-RPR mechanism with direct current drive electric motors made it possible to study the accuracy characteristics of the robot depending on the selected mode of changing the tasks of controlling the length of its drive links. During the experiment, various possibilities of realizing the movement of a parallel robot along a pre-calculated path were investigated. The best mode, ensuring a minimum of dynamic deviation of the actual trajectory from the given one, is now recognized as a uniform change in the tasks of the control loops of the length of the drive links in time using linear Lagrange interpolation.
Towards the development of a toolkit for assessing the critical competencies of agricultural sector employees
Authors: Aletdinova A A , Kiprisheva A I
Published: November 2020

One of the tools for assessing the critical competencies of employees can be an expert system. The authors conducted a theoretical study of critical competencies and identified the following groups relevant in the agriculture: intellectual-educational, communicative, motivational-volitional, management, networking, environmental. Considering competences as variables of the expert system, it is necessary to determine the method for obtaining their values. Today there are no methods for assessing critical competencies. Therefore, the authors decided to use the results of the survey of respondents after the adaptation of existing methods for determining personality characteristics in psychology. Based on the correlation analysis of the results of the survey, the authors excluded the multicollinearity of competences and selected significant variables that were recommended for use in creating an expert system.
The cascade equivalent A-H-circuit of the DC machine
Authors: Blanc A V
Published: November 2020

Cartesian and cylindrical laminated models are well known in the electromagnetic calculations of electric machines. In such models, the general solutions of partial differential equations are transformed into the four-terminal circuit equations, and this allows synthesizing the cascade equivalent circuits of electric machines. In salient-pole machines, the solutions of partial differential equations are formed on the base of the piecewise continuous Sturm-Liouville eigenfunctions. However, in this case, the cascade equivalent circuits cannot be synthesized since it needs many piecewise continuous functions in the zone of poles and many smooth functions in the zone of the air gap for ensuring the uniqueness of the solution. For this issue, the approximate method is offered. This method is based on the single piecewise continuous Sturm-Liouville eigenfunction in the zone of poles and many smooth functions in the zone of the air gap. The method allows transforming the analytic solution of the partial differential equation into the four-terminal circuit equations and synthesizing the cascade equivalent circuits of the salient-pole electric machines. In this paper, the synthesis of the cascade equivalent A-H-circuit of the DC machine is considered. The active cell that corresponds to stator poles is synthesized on the base of the solution of Poisson’s equation with the single piecewise continuous Sturm-Liouville eigenfunction.
Investigation of plasma-ohmic electric furnaces for gasifying carbonaceous wastes
Authors: Domarov P V , Anshakov A S , Aliferov A I , Sherednichenko V S
Published: November 2020

For the first time, the processes of reducing the energy consumption of a plasma-ohmic electric furnace for the gasification of various carbon-containing wastes (municipal, biological, agricultural, and other organic wastes) were investigated. The effect of reducing the humidity, the morphological composition of waste on energy consumption during plasma gasification of carbon-containing materials is shown. The possibility to exclude the process of preliminary drying from the production cycle of waste gasification has been revealed.
Species of vacuum chamber design with cryogenic cooling for strontium optical clocks
Authors: Gurov M G , Gurova E G , Rozanov S B , Slyusarev S N
Published: November 2020

The paper briefly reviews the reasons for the optical clock resonance shift due to thermal radiation. The ways to decrease thermal radiation influence with modification of the spectroscope by introducing of the cryogenic elements as an environment of the atoms from a cryogenic nozzle to create special internal chamber with the example of 87Sr optical clocks are shown. The possibility and usefulness of using the double-circuit dual-mode cryogenic chamber to suppress thermal shift in a strontium optical clocks are considered. The selection of the each element material of the chamber is based on simulated thermal distributions and heat flows of these elements. The detailed concept of this double-circuit dual-mode chamber and calculation of the shifts from each element of this chamber are also presented.
Physical approach to analysis of induction motor braking under machinery load
Authors: Sattarov R R , Morozov P V
Published: November 2020

The mechanical braking process of induction motors during short interruptions, and full switching off is studied in the paper. The approximate approach to solving a differential equation is used for the theoretical analysis of the braking process. The comparison of this approach with the exact solution shows its good accuracy. The used procedure is simple for a deep understanding of physical processes. It is shown that good results could be obtained for both full-stopping and braking due to sags if the right collocation point is chosen. This approach could be used for the study of different transients in electric motors and drives. It helps beginner students to understand clearly the main features of transients. However, it is also useful for experienced engineers who can easily obtain design formulas.
Electrical processes analysis in a wireless power transfer system for electric vehicle battery charging
Authors: Novolodskiy M V
Published: November 2020

The article considers the electrical processes taking place in a wireless energy transfer system for charging the battery of an electric vehicle. The main way to transfer energy through the airspace between the road and the electric car is the inductive coupling of two coils. It is known that the efficiency of the system increases if electric resonance is established in two independent circuits. The choice of the resonant frequency largely depends on the resonant circuit. The work aims to analyze a series-series resonance circuit and justify the choice of a resonant frequency for a given topology. As a result of the study, the author has obtained the dependences of the active and reactive resistance on the frequency, the possible resonance conditions, and a bicubic equation that allows calculating the resonant frequencies for those two types of resonance. Moreover, a computer model has been created, the parameters of which determined the optimal resonant frequency. This research work helps to choose reasonably resonant frequencies depending on the required efficiency of the system with a series-series resonant circuit.