bluuebunny/crossref_metadata_2025 huggingface dataset:
Deformation Aging in Low Carbon Steels
Authors: Mikhailov Sergey , Sharapova Valentina , Skobelina Ekaterina , Molokov Leonid
Published: October 2021

The results of mechanical spectroscopy are shown when studying the processes of strain age-hardening in mild steel with a ferrite-bainitic structure.
Investigation of the Composition, Structure and Properties of New Porous Powder Friction Coatings Obtained by Plasma Sputtering
Authors: Karlov V. I. , Krykhtin Yu. I.
Published: October 2021

The paper investigates processes of composition selection, structure formation and properties of new porous powder friction materials based on molybdenum (Mo), on aluminum-iron bronze (БpAЖ(SiC)) or steel (40X13) obtained by plasma spraying. The study can be used in the frictional devices of transmissions of tracked vehicles with a high specific power to increase the tribotechnical, operational and technological characteristics.
Investigation of the Evolution of Magnetic and Acoustic Characteristics as a Result of Annealing of Cold-Deformed Nickel
Authors: Kostin Vladimir , Serbin Evgeny , Vasilenko Olga
Published: October 2021

The change in the magnetic and acoustic properties of nickel as a result of cold deformation and subsequent annealing is investigated. It was found that annealing leads to very significant changes in the magnetic and acoustic properties of nickel. The coercive force decreases 50 times with an increase in the annealing temperature to 800 °C. The Rayleigh coefficient, which characterizes the mobility of domain walls, monotonically increases by a factor of 20 over the entire investigated range of annealing temperatures. The greatest changes in the velocity and damping of longitudinal ultrasonic vibrations occur in the range of recrystallization temperatures. It is shown that to diagnose the structure and magnitude of residual stresses in nickel, it is advisable to determine its magnetic and acoustic parameters.
Application of coercimetry to assess the functional properties of materials
Authors: Kostin Vladimir , Ksenofontov Danila , Vasilenko Olga , Byzov Alexander
Published: October 2021

The purpose of this work is a comparative study of the possibilities of various types of coercimeters to assess the functional properties of ferromagnetic materials. Conducted research have shown that the limitation of the maximum measured value of the coercive force using an attached transducer with a U-shaped electromagnet is due to the lower value of the magnetic resistance of the tested workpiece. The upper limit of measurements of the coercive force using a two-pole transducer is determined by the magnitude of the tangential component of the magnetic field only by the possibility of magnetizing the tested object.
Durability of Polymer Powder Coatings
Authors: Fedyaev Vladimir , Galimov Engel , Belyaev Alexey , Sirotkina Liliya
Published: October 2021

The durability of polymer powder coatings is considered. The features of the impact on coatings during their operation of the environment, loads from the side of the substrate on the surface of its contact with the coatings, parameters that depend on the chemical composition and structure of the coating material are briefly analyzed. The thickness of the coating stands out as the main indicators of durability; a function that characterizes the continuity, strength, corrosion resistance, and its other properties; adhesive strength. It is proposed to use a generalized (integral) criterion for a comprehensive accounting of these indicators. An equation is written to assess the durability of the considered coatings, in a particular case, a formula is given for calculating their permissible operating time.
Fuzzy Models for Evaluating the Effect of Radio Frequency Electromagnetic Fields on Health
Authors: Titova Anna V. , Korenevskiy Nikolay A. , Goltsova Mariia Iu.
Published: October 2021

Numerous studies of domestic and foreign researchers show that long-term exposure to electromagnetic fields (EMF) of artificial radio frequency range have negative effects on the human body. At the same time, if the effects of EMF of significant intensity are sufficiently well studied and regulated by the relevant sanitary norms and rules and state Standards, the harmful effects of low-intensity EMF are confirmed by many researchers, but there are practically no quantitative estimates of their impact on human health in combination with other exogenous and endogenous factors. In real conditions, the human body is often exposed to combined, combined and mixed EMF effects of various frequency ranges of different intensity, which cause a multiplicative effect, leading to an increased risk of occurrence and development of a number of socially significant diseases, especially when they are long-term exposure
Optimization of MFA parameters for harrowing crops with simultaneous fertilization
Authors: Serguntsov Alexander , Alekseenko Leonid
Published: October 2021

The calculation of the energy intensity of the harrowing process of winter crops with simultaneous fertilization is theoretically justified by drawing up a flowchart with a step-by-step calculation of the parameters and operating modes of a multifunctional unit. The flowchart shows the parameters and operating modes that are set and that need to be calculated to achieve the goal of calculating energy intensity. In the course of calculations, we constructed the dependence of energy consumption on the operating speed, that is, we determined the minimum energy consumption at maximum power when using a multifunctional unit.
Justification of the Coefficient of Use of the Working Time of the Unit Change for Harrowing Winter Crops with Simultaneous Top Dressing
Authors: Serguntsov Alexander , Lagoda Sergey
Published: October 2021

The dependences of the coefficient of use of the working time of the change of the proposed multifunctional unit for harrowing winter crops with simultaneous additional fertilizing with solid mineral fertilizers are theoretically justified. In the conditions of agriculture of Krasnodar Territory, with an increase in the working speed of the unit, a significant decrease in this coefficient was found for various ruts and capacities of the fertilizer silo. For the proposed unit, all components of the cycle time spent on performing two working and two idle passes through the field with the shuttle method of movement, as well as the number of cycles per shift, the actual duration of the shift time and its utilization rate are calculated. With an increase in the working speed of the unit, all other things being equal, the value of the shift time coefficient decreases.
Dependence of Elastic Deformations of Spindle-Tool Subsystem on Influence of Cutting Force Radial Component
Authors: Kazakova O. Yu. , Gasparova L. B.
Published: October 2021

The results of field research are presented in the article. The parameters that affect the position of the tool in the spindle of the machine are determined. The tasks concerning the identification of the angular position of the tool in the spindle are solved. The issues of the influence of the cutting force radial component on elastic angular deformations in the spindle and tool contact area are considered.
Forecasting Sales Volumes of Small and Medium-Sized Machine-Building Enterprises
Authors: Ershova Irina V. , Prilutskaya Maria A. , Klyuev Andrey V.
Published: October 2021

In the article, the authors considered the possibilities of forecasting sales based on the use of ABC analysis tools, the customer potential coefficient and the degree of customization of orders. The object of the study was five medium-sized machine-building enterprises. The method is based on static grouping and analysis of actual sales volumes in the context of customers and the range of orders. The peculiarity of these enterprises is the presence of a large pool of customers with low repeatability of orders. The analysis showed that the majority of Group A customers have low customer potential and stable or declining demand. The largest increase in orders was observed among the customers of Group B. The level of customization of the order increases customer loyalty, but increasing the level of customization reduces the economic efficiency of the activity. The authors suggest direct planning of the basic part of the sales volume based on the achieved level of orders by customers of Groups A and B with the customer potential above 1. The additional part of the sales volume determined by the goals of the enterprise, its resources and planned based on an increase in the level of customization.
Stochastic Processes Occurring during the Transition of Technical State of the Structure
Authors: Izvekov Yury , Tulupov Oleg , Dubrovsky Vladislav , Kanel-Belov Alexey
Published: October 2021

The possibility of applying the theory of stochastic processes for evaluating the dynamic pattern of different states is studied for critical-duty structures. Heterogeneous Markovian processes of technical state transition for metallurgical overhead crane structure, Markovian theorem and Kolmogorov-Chapman equation are analyzed. Markovian chain is reviewed at t →∞, i.e. under marginal steady-state (stabilized) condition. Real values of limit probabilities are obtained for the structure of the metallurgical overhead crane under review. The proposed approach redefines and elaborates the existing methods and procedures for evaluating the technical state of structures and reduces the level of ambiguity associated with such kind of problems.
Mechanical Engineering Product Value Design Applying the Value Engineering Method
Authors: Prilutskaya Maria , Murukina Anastasia , Dashkova Tatiana
Published: October 2021

Today mechanical engineering is one of the most dynamically developing industries. The products of this industry are becoming more and more complex, requiring the continuous introduction of new high technologies into the production process. In addition, the change in the preferences of consumers of mechanical engineering products associated with an increase in the degree of automation and robotization of their production processes leads to the need to apply more flexible product design approaches. These approaches should allow the manufacturer to respond quickly to changing customer needs. Thus, machine-building enterprises need to provide not only the best price-quality ratio, but also to offer a unique set of product functions - a concept that satisfies all the needs of target consumers. In other words, the ability to create product value based on the individual needs of customers is a competitive advantage for a company in the struggle for market share. The application of Value Engineering Method is able to solve these problems.
Simulation Modeling of the Tilting Mechanism of the Main Trolley of the Turnaround Charging Crane
Authors: Spiridonov V. A. , Tkachenko A. M. , Slavnitskiy R. A. , Biushkina A. S.
Published: October 2021

this article contains kinematic and dynamic analysis of the tilting mechanism of the turnaround charging crane main trolley, conducted with the use of the Mathcad package. The mechanism is modeled by a flat link mechanism – a four-bar linkage. In the same time, the analysis of the mechanism is also conducted using the Matlab Simulink environment and the tools of Multibody, which is a Simulink library. These two models were then compared. In the study the work-energy theorem and Holonomic constraints equations were used.
Digitalization of Industry and Education
Authors: Ostapenko Mariya , Nazarova Vladlena
Published: October 2021

The fourth industrial revolution, associated with the introduction of robotics, cyber-physical systems, artificial intelligence, neural networks, affects all spheres of human life. There is a need for specialists with the appropriate skills. The article discusses the elements of Industry 4.0: Internet of Things, robotization, PLM system. The impact of digitalization on the educational sector is also considered.
Cutting tool standardization
Authors: Ostapenko Maria , Voronova Natalya
Published: October 2021

The article aims to determine the role of standardization in the engineering industry and for cutting tools in general. This paper explains the basic principles of standardization. The technical committee for standardization of cutting tools (TC 95 ‘Tools’) was presented. The main directions of work and functions of TC 95 ‘Tools’ are explained. Harmonization of standards in Russia is presented on the example of ISO 13399 international standard. The work reveals positive aspects of officially translated versions of standards for enterprises. The article also describes the role of standardized tools when working in computer-aided design systems (CAD).
Modeling of a Railway Sanding System Using Vibration Fluidization
Authors: Bulavin Y.P. , Konovalov P.Y.
Published: October 2021

The model of the sand distributor of the sand feeding system of traction rolling stock, the operation of which is based on the effect of vibration fluidization of sand, has been considered. A pneumatic pulsator was used as a source of vibration impact. Experimental studies have shown that this design allows for a continuous regulated supply of sand. The power of the sand distributor membrane vibrations at the disturbing frequency can be used as a criterion characterizing the impact of the pulsator on the sand. There is a close to linear dependence of the sand flow rate on the power of vibrations.
Integration of Descriptions of Static Structures at Automation of Design Tasks
Authors: Novoselova Olga , Sidorov Anton
Published: October 2021

This paper investigates the process of integrating descriptions of static structures in the form of charts and specifications at the stage of conceptual modeling of automated systems, that are developed to solve design tasks. In the process of creating an automated system based on the methodology for automating intellectual labor (MAIL), models of design tasks are formed: initial, conceptual, infological and datalogical. The conceptual model describes the system of concepts of the subject area. The description of conceptual model representation includes specifications and charts: for a static component - F1 and F2, the chart of conceptual structure; for a dynamic component - F3 and F4, the chart depicting a system of subject dependences; F6 and the matrix chart showing the model as a whole including static and dynamic components coordination. The features of constructing diagrams and forming specifications in the formation of a conceptual structure are studied, on the basis of which the method and technique to integrate descriptions of static components for the system of concepts of the subject area are determined. The article is given the integration of descriptions in the form of diagrams and specifications for the static components of conceptual model representations.
Investigation of the Influence of the Space Orientation of Layers on the Surface Shape Error during Additive Shaping of Products by an Electric Arc in a Protective Gases Environment
Authors: Grechukhin Aleksandr , Kuts Vadim
Published: October 2021

The paper presents the results of a study of the process of additive surface shaping by an electric arc in a protective gas. An analysis was made of the errors in the shape of surfaces obtained with different filling of layers. It has been experimentally confirmed that such process parameters as the orientation of the layers, the coefficient of their overlap are significant and affect the numerical value of the error in the shape of the resulting surface. In this connection, they should be taken into account when designing algorithms for dividing into layers and filling them with additive shaping by an electric arc in a protective gas.
Investigation of the Efficiency of a Granular Filter Based on Cement Clinker
Authors: Sharapov Rashid
Published: October 2021

The article describes the process of cleaning dusty gases. Attention is paid to the devices for fine cleaning of dusty gases. Attention is focused on the fact that the most simple and, at the same time, effective dust cleaning device is a granular filter. Its advantage is shown when cleaning dusty air from very aggressive devices, when working on high-temperature and aggressive gases. The prospects of granular filters, in which a cement clinker is used as a filter material, with a granule size of up to 10 mm, are shown. The main causes of dust deposition on grains, filaments or fibers are presented. Various approaches to determining the empirical dependences of the dust span on the design parameters of the filter apparatus are presented. The criterion dependence of the cement dust span is presented, which approximates the results of the experiment. It allows you to determine the efficiency of the granular filter from its design and technological parameters.
Determination of Design Solution for a 6x6 ATV with an Electromechanical Transmission
Authors: Evseev Kirill , Dyakov Aleksey , Goncharov Roman , Chutkov Konstantin
Published: October 2021

The article provides an overview and analysis of the current state of development of 6x6 ATVs and the scope of the developed ATV, as well as technical characteristics of 6x6 ATVs with a mechanical transmission. The choice and justification of design solutions for a 6x6 ATV with an electromechanical transmission are presented. Also, the selected structural and design solutions for the developed ATV are substantiated based on the selected electric drive scheme taking into account the traction calculation for the selected electric motor.
Selection of a Multi-Functional Controller for the Software and Hardware Complex of an Automated Control System for a Thermal Power Plant
Authors: Dmitrieva Valeria , Sizin Pavel , Avkhadiev Ilyas
Published: October 2021

The article describes the main tasks that need to be solved when automating technological processes at TPS. Technological processes at TPS take place in difficult conditions, which complicates the management tasks. When creating an automated control system, modern software and technical complexes are used, which are developed by domestic manufacturers. The software and hardware complex allows you to solve all the problems of monitoring and controlling technological processes in all operating modes of power equipment. They can be used for both newly constructed and reconstructed energy facilities. The basis of the Software and hardware complex is programmable logic controllers that support medium and distributed automation. The article discusses some Russian-made controllers. Since 2019, the automated control system of the boiler-economizer is being designed by NVT-Systems at the Dzerzhinsk TPS. The implemented Software and hardware complex needs to be integrated into the existing automation structure, in addition, simplicity, reliability and redundancy are required. For these reasons, the REGUL500 controller was selected. The controller is characterized by very high performance, reliability, and the ability to work in distributed systems in real time. In addition, the advantages of the REGUL500 controllers are: high accuracy of the measuring channels; the possibility of hot-swapping modules of all types; resistance to external influences. The REGUL controller has a set of various Russian certificates of conformity.
The Development of a Simulation Model for Assessing the CI/CD Pipeline Quality in the Development of Information Systems Based on a Multi-Agent Approach
Authors: Medvedev Denis , Aksyonov Konstantin
Published: October 2021

The need for the development of fast and efficient software requires the automation during the build, test and release stages. Thus, a methodology of the continuous integration and continuous delivery (CI/CD) emerges which using a continuous integration server which makes easier automatical build, test, and package of the new feature settings. Poor understanding and execution of CI/CD operations can slow down and even stop the pace of a software project. Many bottlenecks in the CI/CD pipeline can arise from misconfiguration, in other words, an inadequate level of automation, inappropriate agent characteristics, and a suboptimal queuing strategy. On the other hand, the finding a way to analyze and improve the settings of the CI/CD pipeline brings great management and economic benefits, since an optimal configuration ultimately implies high efficiency. In this regard, this study attempts to develop a simulation model that will provide a testing environment for a variety of factors that affect CI/ CD performance. The present study, therefore, aims to provide a pipeline simulation model based on the logic of a queuing system, which is based on a multi-agent approach and an experimental environment that allows you to test different settings and scenarios.
Stress-Deformed Condition at Different Angle of Scratch Inclination on Flat Cover of Hatch-Blade
Authors: Rubtsov Aleksey , Mukhametzyanov Zinur , Kulakov Petr , Gracheva Veronika
Published: October 2021

Defects of mechanical origin are quite often found on the structural elements of the devices of the production facilities of the fuel and energy complex. One of the most common mechanical defects is scratches and hairlines on the outer surface of the structural elements. The current regulatory and technical documentation establishes standards for the rejection of defects of various types, which provide for the decommissioning of objects with unacceptable defects for repair or subsequent dismantling. However, in most cases, mechanical defects such as scratches are within acceptable sizes and do not have a decisive effect on the life, reliability and safe operation of vessels and apparatus. However, the presence of such defects can change the stress-strain state of the object to a more unfavorable side, and therefore accelerate the process of accumulating damage at points of concentration of increased stresses. Subsequently, places with a concentration of increased voltages under certain operating conditions can be sources of premature destruction of the element and failure of the object as a whole. Therefore, the actual work is the simulation of the stress-strain state of the flat manhole cover with a scratch, having a different arrangement. In this work, the stress-strain state of the flat manhole cover is examined depending on the location of the scratch on it at a different angle relative to the vertical axis of symmetry of the cover.
Increasing Mobility of Tracked Vehicles during Curvilinear Motion by Redistributing Power Flows
Authors: Taratorkin I.A. , Vyaznikov M.V. , Vyaznikov A.M.
Published: October 2021

A kinematic diagram of an electromechanical transmission of a high-speed tracked vehicle with two traction electric motors, on-board gearboxes and a ZK-type differential turning mechanism, which makes it possible to effectively distribute power flows between the sides during curvilinear motion, is proposed.
Theoretical Substantiation of the Angle of Mounting a Flat Ridge-Forming Disc of a Row Crop Cultivator
Authors: Zykin Evgeny , Kurdyumov Vladimir , Lazutkina Svetlana
Published: October 2021

The authors have developed a row-crop cultivator equipped with a ridge former, which allows performing high-quality operations of row crop cultivation in one pass. The inter row cultivation is carried out with a row-crop cultivator, on each section of which two ridge formers are mounted so that their flat discs are directed towards the row of plants at an acute angle, and the extreme edges of the wings of the V-shaped sweeps are located at the lower base of the soil ridge. When the row-crop cultivator moves, the V-shaped sweeps loosen the soil to the required depth and cut the weeds, and the flat discs move the soil layer coming off the wings of the V-shaped sweeps towards the rows of plants, hilling them and burying the weeds. In the presented article, the authors theoretically substantiate the angle of attack of a flat disc for burying weeds with a layer of soil of the required thickness. It was found that the angle of attack depends on the radius of the flat disc and the depth of its movement in the soil, the initial dimensions of the ridge and the physical and mechanical properties of the soil.
Control Algorithm Selection Technique for Vehicle Robotic Transmission in the Urban Cycle
Authors: Sarach Evgeniy , Tsipilev Alexander , Smirnov Igor
Published: October 2021

Environmental pollution is one of the most crucial problems in modern world. The toughening of emission standards for toxic fumes, which appear due to the combustion of fossil fuels in internal combustion engines, forces manufacturers to reduce fuel consumption, for example, via more rational use of the internal combustion engine capabilities. This paper is devoted to developing a control algorithm selection technique for economy class passenger car robotic transmission in the conditions of an urban cycle, using Lada Vesta SW Cross as a research subject. At the beginning of the paper, vehicle movement imitational mathematical model implementation, which was developed using LMS Imagine. Lab Amesim program complex. is shown. Also the main assumptions and parameters of engines, cooling systems, transmissions and chassis are given. Then imitational mathematical model verification results, which were processed by comparing movement computer simulation results with the vehicle passport data, are shown. Imitational mathematical model demonstrates the car behavior adequately and very precisely, which means it can be used for vehicle fuel efficiency research. In the main part of the paper, vehicle movement research is conducted in case of three different versions of the internal combustion engine (which has 1,4-, 1,6- and 1,8-liters volume) used in an urban cycle INRETS urbanfluide2. It is clearly shown that the lowest consumption is achieved by reducing the acceleration and braking dynamics via “early” gear shifting, and the crankshaft rotation speed at the corresponding moment of the shift has to be selected for each gear separately. Based on the research results, a switching algorithm and its selection technique, which takes the throttle valve opening degree and the type of the internal combustion engine external speed characteristic into consideration, are presented. In conclusion, this paper presents the results of vehicle movement imitational mathematical modeling in the urban cycle with a modified robotic transmission control algorithm. It is clear that this algorithm can reduce fuel consumption in the urban cycle by 12-20%, depending on the engine volume.
A Case Study on Implementation of 5S in a Manufacturing Plant to Improve Operational Effectiveness
Authors: Monnanyana Ofentse , Gupta Kapil
Published: October 2021

5S is one of the important industrial engineering techniques to obtain workplace organization and efficiency enhancement. This paper reports a case study on implementation of 5S in a factory facility of a valve manufacturing company. The aim behind implementing 5S is to improve the productivity and efficiency by reducing the factory chaos, reducing the tool and material search time, and arranging the workplace for a better visibility of the machines, equipment, and items. Audit checklists, workplace pictures, and time study have been used to analyse the effect of 5S implementation. A strategic 5S implementation in this work resulted in much better workplace organization; improved visibility, appearance, and orderliness of objects; and significant reduction in the time to search or access tools.
Theoretical Study of the Process of Separating the Tobacco Leaf from the Stem
Authors: Papusha Sergey , Domrin Andrey
Published: October 2021

The article is devoted to the cleaning of tobacco leaves by the leaf-by-leaf method, using a roller-type separating device acting on the object of cleaning with a drum knife having cutting edges, forming leaf-separating cells in the working area. The subject of these studies is highly specialized and relates to the field of agricultural engineering. Tobacco plants were selected as the object of processing. The purpose of the research was the theoretical substantiation of the interaction of tobacco stalks with the leaf-separating apparatus in the harvesting process. The article is of a research type, which is expressed in the fact that a theoretical analysis of the interaction of a tobacco plant with a leaf-separating device of a knife-drum type in the cleaning process is carried out. As a result of the research, dependencies were obtained that allow determining the design and technological parameters of the separating apparatus for separating a tobacco leaf. The conclusions present the main results achieved so far.
The Process of Ultra Low-Volume Seed Etching by an Experimental Device
Authors: Papusha Sergey , Kozhura Filipp , Zhadko Valeria
Published: October 2021

The main way to protect plants from diseases and pests is the treatment of seed material with pesticides. To achieve maximum efficiency from complex seed treatment, it is necessary to evenly distribute the drug over the surface of all available seeds. One of the conditions for operation of the etcher is the possibility of connecting to the compressor unit and the electricity network. The performance of the sprayer was studied depending on the pressure in the pneumatic system of the spraying device and the diameter of the feeding tube.
Innovative Kommunikation: Wie „Design Thinking“ ein deutsches Krankenhaus prägt
Authors: Guntermann Bastian , Hladik Joachim
Published: October 2021

Die Waldkliniken Eisenberg beschreiten neue Wege im Umgang mit Patienten und Mitarbeitern. Dazu gehört auch ein Marketing, das aktiv über Social-Media-Kanäle auf die Patienten zugeht.
Time evolution of spin singlet in static homogeneous exchange and magnetic fields
Authors: Kuplevakhsky S. V. , Bengus S. V.
Published: October 2021

Within the framework of an idealized theoretical model, we study the effect of external static homogeneous exchange and magnetic field on the spin part of the singlet wave function of two electrons. We begin by revising the traditional (textbook) approach to the spin singlet. Basing our own approach solely on the property of invariance under rotations of the coordinate system and using the theory of spinor invariants, we derive a generalized representation of the spin singlet whose main feature is that the spins are in mutually time-reversed states. We show that exactly this feature predetermines the actual form of the Hamiltonian of interaction with the external field and stipulates time evolution of the singlet. Some applications of these results to the theory of superconductivity and spin chemistry are presented. In particular, it is shown that the case of ferromagnetic superconductors constitutes a good illustration of the validity of our quantum-mechanical consideration.
Magnetoresistance of electrons in quantum ring with Rashba spin-orbit interaction
Authors: Babanlı A. M. , Uçar Osman
Published: October 2021

The influence of Rashba spin-orbit interaction on the transport properties of the two-dimensional quantum ring with finite width has been investigated in the presence of the uniform perpendicular magnetic field. The dependence of magnetoresistance on the magnetic field and Rashba spin-orbit coupling parameter in quantum ring with finite width are investigated. It was shown that in the presence Rashba spin-orbit interaction that the beating pattern is destroyed.
Fast-slow analysis demonstrates mechanism for stochastic endocrine cell electrical bursts
Authors: Liebendorfer Adam
Published: October 2021

Findings in a mathematical model for cells in the pituitary gland highlight the role of certain potassium channels in electrical activity and hormone release.
Fast-slow analysis of a stochastic mechanism for electrical bursting
Authors: Fazli Mehran , Vo Theodore , Bertram Richard
Published: October 2021

Electrical bursting oscillations in neurons and endocrine cells are activity patterns that facilitate the secretion of neurotransmitters and hormones and have been the focus of study for several decades. Mathematical modeling has been an extremely useful tool in this effort, and the use of fast-slow analysis has made it possible to understand bursting from a dynamic perspective and to make testable predictions about changes in system parameters or the cellular environment. It is typically the case that the electrical impulses that occur during the active phase of a burst are due to stable limit cycles in the fast subsystem of equations or, in the case of so-called “pseudo-plateau bursting,” canards that are induced by a folded node singularity. In this article, we show an entirely different mechanism for bursting that relies on stochastic opening and closing of a key ion channel. We demonstrate, using fast-slow analysis, how the short-lived stochastic channel openings can yield a much longer response in which single action potentials are converted into bursts of action potentials. Without this stochastic element, the system is incapable of bursting. This mechanism can describe stochastic bursting in pituitary corticotrophs, which are small cells that exhibit a great deal of noise as well as other pituitary cells, such as lactotrophs and somatotrophs that exhibit noisy bursts of electrical activity.
Substrate dependent reduction of Gilbert damping in annealed Heusler alloy thin films grown on group IV semiconductors
Authors: Love C. J. , Kuerbanjiang B. , Kerrigan A. , Yamada S. , Hamaya K. , van der Laan G. , Lazarov V. K. , Cavill S. A.
Published: October 2021

A structural and FMR study is presented for epitaxial thin films of the Heusler alloy Co2FeAl0.5Si0.5 (CFAS) grown on Ge(111) and Si(111) substrates. All films, as-grown and post-annealed, show B2 ordering; full chemical order (L21) is not obtained over the range of anneal temperatures used in this study. As-grown films show a lower Gilbert damping constant, α, when grown on a Si(111) substrate compared to Ge(111). Annealing the films to 450 °C significantly reduces α for CFAS on Ge while increasing α for CFAS on Si. This is related to a substrate dependent competition between improvements in lattice structure and increased interfacial intermixing as a function of anneal temperature. The optimal annealing temperature to minimize α is found to differ by ∼100 K between the two substrates. Above an anneal temperature of 500 °C, films grown on both substrates have increased coercivity, decreased saturation magnetization, and show characteristic two-magnon scattering features.
Enhancement of fluorescence of single quantum dots by encasing in semiconductor and metal nanoparticles
Authors: Rani Sweta , Kumar Jitendra
Published: October 2021

Quantum dots (QDs) are widely investigated in the field of optoelectronics due to their various unique spectral and excellent fluorescence properties. However, QDs suffer from intermittent fluorescence, also known as blinking, that limits their use in optoelectronic devices. The blinking mechanism can be suppressed by numerous processes, and one such process includes the interaction of the QDs with semiconductor nanoparticles (NPs) such as indium tin oxide (ITO) and titanium dioxide (TiO2). By encapsulating the QDs in these NPs, the blinking rate is significantly reduced due to the electron transfer pathway between them. The interaction of QDs with metal NPs such as silver (Ag) and gold (Au) also greatly enhances the fluorescence behavior due to energy transfer and plasmonic effects. This work deals with the electron transfer model that analyzes the effect of radiative recombination, non-radiative recombination, and electron transfer between QDs and the NPs. An analysis of the on and off states for QDs under the influence of considered NPs has also been done. The on and off time for QDs have also been studied, which provide a comprehensive framework of the performance of the QDs interfaced with these NPs. A comparison between the QDs interacting with glass and other semiconductor and metal NPs is also drawn to compare the efficacy of QDs under the influence of different NPs. This analysis postulates the physical mechanism for blinking and ways to curb these mechanisms using the semiconductor and metal NPs. The theoretical study demonstrates the quantitative insights and prerequisites for designing QD-based optoelectronic devices.
Kinetic theory of double layers driven by temperature anisotropy in a non-homogeneous magnetic field
Authors: Kumar Harihara Sudhan , Takahashi Masayuki , Kato Chinami , Oshio Yuya , Ohnishi Naofumi
Published: October 2021

A double layer (DL) is created in a plasma when the plasma is perturbed in the presence of a temperature anisotropy. We derive a new simple theory for the existence of an unstable, non-oscillatory electrostatic DL-like structure in the presence of a magnetic field gradient in a collisionless plasma with a temperature anisotropy in the direction perpendicular to the magnetic field. The DL is treated as a wave perturbation in the plasma using kinetic theory with a gyro-kinetic approximation to obtain a dispersion relation. The presence of an electron temperature anisotropy is the necessary condition to obtain an exponentially growing instability, and the corresponding growth rate is found to be the ratio of the electron kinetic energy and the electric field energy across the DL region. The theoretical predictions are then validated against a one-dimensional electrostatic particle simulation carried out in a traveling magnetic field thruster environment. An anisotropy ratio parameter was introduced, and the theoretical growth rates were found to be in good agreement with the simulation for different anisotropy ratios. An ion beam, associated with the DL dynamics, is observed within the simulation domain. A parametric study revealed that the DL-like structure loses its ambipolar shape for temperature ratios less than 10. It has been found that a stronger anisotropy is required to obtain the DL-like structure.
Model-free inference of unseen attractors: Reconstructing phase space features from a single noisy trajectory using reservoir computing
Authors: Röhm André , Gauthier Daniel J. , Fischer Ingo
Published: October 2021

Reservoir computers are powerful tools for chaotic time series prediction. They can be trained to approximate phase space flows and can thus both predict future values to a high accuracy and reconstruct the general properties of a chaotic attractor without requiring a model. In this work, we show that the ability to learn the dynamics of a complex system can be extended to systems with multiple co-existing attractors, here a four-dimensional extension of the well-known Lorenz chaotic system. We demonstrate that a reservoir computer can infer entirely unexplored parts of the phase space; a properly trained reservoir computer can predict the existence of attractors that were never approached during training and, therefore, are labeled as unseen. We provide examples where attractor inference is achieved after training solely on a single noisy trajectory.
Fe-related optical transitions in floating zone and Czochralski grown β-Ga2O3 crystals
Authors: Bhandari Suman , Zvanut M. E.
Published: October 2021

Gallium oxide (Ga2O3), a promising candidate for high-power electronics, may be doped with Fe to control the native n-type conductivity and produce semi-insulating single-crystalline substrates. Here, intentionally as well as unintentionally Fe-doped β-Ga2O3 crystals grown by the Czochralski (Cz) and the floating zone (FZ) methods are studied. While the Cz samples contain Ir on the order of 1017 cm−3 due to the Ir crucible, the FZ samples are free of this contaminant. Photoinduced electron paramagnetic resonance (EPR) is performed by illuminating the samples with light emitting diodes from 0.7 to 4.7 eV while monitoring the intensity of the EPR signal. The following optical transitions associated with Fe are observed: one between 1 and 2 eV occurs in both Cz and FZ samples, another near 2.5 eV is unique to Cz Ga2O3, and a third near 3 eV appears in FZ material. The transition below 2 eV is the well-studied Fe2+-to-Fe3+ transition, intrinsic to Fe. Near 2.5 and 3 eV, the amount of Fe3+ decreases by capturing electrons excited from other defects present near or below the middle of the bandgap. By comparing Cz and Ir-free FZ crystals, we show that the 2.5 eV transition is primarily caused by Ir in Fe-doped Cz samples, whereas the ∼3 eV transition observed in FZ samples could be caused by isolated or complex intrinsic defects. By differentiating transitions between Cz and FZ material, the results will be relevant to epitaxial films, which do not contain the Ir present in the commonly studied Cz material.
Delayed epidemic peak caused by infection and recovery rate fluctuations
Authors: Arutkin Maxence , Faranda Davide , Alberti Tommaso , Vallée Alexandre
Published: October 2021

Forecasting epidemic scenarios has been critical to many decision-makers in imposing various public health interventions. Despite progresses in determining the magnitude and timing of epidemics, epidemic peak time predictions for H1N1 and COVID-19 were inaccurate, with the peaks delayed with respect to predictions. Here, we show that infection and recovery rate fluctuations play a critical role in peak timing. Using a susceptible–infected–recovered model with daily fluctuations on control parameters, we show that infection counts follow a lognormal distribution at the beginning of an epidemic wave, similar to price distributions for financial assets. The epidemic peak time of the stochastic solution exhibits an inverse Gaussian probability distribution, fitting the spread of the epidemic peak times observed across Italian regions. We also show that, for a given basic reproduction number R0, the deterministic model anticipates the peak with respect to the most probable and average peak time of the stochastic model. The epidemic peak time distribution allows one for a robust estimation of the epidemic evolution. Considering these results, we believe that the parameters’ dynamical fluctuations are paramount to accurately predict the epidemic peak time and should be introduced in epidemiological models.
Demonstration of ferroelectricity in ScGaN thin film using sputtering method
Authors: Uehara Masato , Mizutani Ryoichi , Yasuoka Shinnosuke , Shiraishi Takahisa , Shimizu Takao , Yamada Hiroshi , Akiyama Morito , Funakubo Hiroshi
Published: October 2021

It is recently found that wurtzite aluminum nitride exhibits ferroelectricity by alloying with scandium. Because its remanent polarization (Pr) is large, ScxAl1−xN has attracted much attention. Gallium nitride with similar structure and properties is also expected to show ferroelectricity. Herein, ScxGa1−xN was prepared on a silicon substrate at 673 K using the sputtering method, and its ferroelectricity was investigated. Sc0.41Ga0.59N exhibited ferroelectricity before dielectric breakdown. Pr of this film, as evaluated via positive-up-negative-down (PUND) measurement, was around 120 μC/cm2, which can reduce the influence of the leakage current. This was comparable to the value of ScxAl1−xN with the same internal parameter u, which is approximately estimated from the lattice constants. Moreover, in the PUND measurement, the measurement temperature dependence of Ec was observed, which was 4.3 MV/cm at 300 K and reduced to 3.2 MV/cm at 473 K.
Advancing thermoelectrics by vacancy engineering and band manipulation in Sb-doped SnTe–CdTe alloys
Authors: Zhang Fujie , He Shan , Li Ruiheng , Lin Liwei , Ren Ding , Liu Bo , Ang Ran
Published: October 2021

A decrease in valence band energy offset can considerably improve the thermoelectric performance of SnTe, and alloying CdTe in SnTe has been confirmed to be efficient for inducing band convergence. However, the low solubility of CdTe in SnTe severely limits the further decrease in the energy offset and the reduction of lattice thermal conductivity. Inspired by the high solubility of Sb in SnTe-based thermoelectric materials, the trivalent Sb is introduced into SnTe–CdTe alloys, aiming at manipulating the thermoelectric transport properties. Combined with the valence band model, it is demonstrated that high concentration of Sb in SnTe–CdTe enables a further optimization in valence band structures, resulting in an improvement in density-of-state effective mass, thus significantly reinforces the power factor in the whole temperature range. Meanwhile, we propose the solid solution mode of Sb in SnTe, which always generates vacancies to balance the valence state, and the introduction of vacancies explains the reduced lattice parameters and almost constant carrier concentration. Particularly, the Debye–Callaway model quantitatively compares the contribution of Sb substitutional defects and vacancy defects. As a result, an enhanced zT of ∼1.1 has been achieved for Sn0.83Cd0.05Sb0.12Te at 823 K. This work clearly shows the critical role of Sb for enhancing the thermoelectric performance of SnTe–CdTe materials.
d
-mannose suppresses oxidative response and blocks phagocytosis in experimental neuroinflammation
Authors: Wang Jing , Jalali Motlagh Negin , Wang Cuihua , Wojtkiewicz Gregory R. , Schmidt Stephan , Chau Cindy , Narsimhan Radha , Kuellenberg Enrico G. , Zhu Cindy , Linnoila Jenny , Yao Zhenwei , Chen John W.
Published: October 2021

Significance

The innate immune response from macrophages and microglia plays key roles in the pathogenesis and repair in neuroinflammatory diseases such as multiple sclerosis. However, current disease-modifying therapeutics do not directly target these cells. Moreover, current drugs are expensive, causing some patients to skip doses or take drug holidays. We found that
d
-mannose not only decreased oxidative stress and blocked phagocytosis but also diminished the proinflammatory response and boosted the antiinflammatory response from macrophages and microglia. Our findings suggest that
d
-mannose, an over-the-counter drug with a high safety profile, may be an effective, low-cost treatment option for multiple sclerosis and other neuroinflammatory diseases. The availability of such a drug could significantly improve patient access to needed drugs and improve outcome.
Artigos definidos variáveis no português europeu dialetal
Authors: Nkollo Mikołaj
Published: October 2021

O presente artigo visa esclarecer a presença do ataque nasal nos artigos definidos em variedades dialetais do Português europeu (PE) contemporâneo. Restringe-se a análise a um contexto nitidamente delimitado, abrangendo, por defeito, os ditongos nasais das sílabas finais da forma verbal conjugada e o artigo a ela posposto, produzindo assim as formasno,na,nos,nas. É um fenómeno inovador na história dos artigos definidos do PE, pois os textos das épocas prévias não comprovam a mudança nessa configuração. A análise baseia-se nos dados reunidos na secção ‘transcrição literal’ do CORDIAL-SIN –Corpus Dialectal para o Estudo da Sintaxe. Além da dimensão variacionista, o presente trabalho aprofunda a natureza flexiva de ambas as formas paralelas. São igualmente estudados os processos fonológicos concomitantes à presença do ataque, ou seja, a monotongação, a perda de nasalidade, bem como a alteração do timbre da primeira das vogais encadeadas. Foi adotado neste estudo o modelo de gramáticas competidoras permitindo assim destrinçar os métodos de processamento dos dados linguísticos. Concebe-se a variação que permeia as sequências:verbo+artigo definidocomo o desfecho da atuação da analogia, inspirada pelas mudanças que incidem na forma dos pronomes clíticos acusativos na ênclise, homónimos dos artigos definidos.