bluuebunny/crossref_metadata_2025 huggingface dataset:
Parameterized FEM for estimation of product unit assembly parameters
Authors: Grachev I A , Kudashov E V , Bolotov M A , Pronichev N D
Published: February 2021

The article analyzes the existing calculation methods for assembly dimensional chains. The analysis revealed factors that are not considered in the methodology as a result, thus reducing reliability of the calculations. One of such factors is link interconnection for some dimensional chains, which must be considered while calculating. The parametrized finite-element model (FEM) of an aviation engine rotor is proposed considering: link interconnection of dimensional chains; geometrical deviations of part surfaces; axial forces from bolt connection; volume deformations. The developed FEM has been used in theoretical and experimental studies of geometric accuracy of the rotor assembly parameters. The research results for interrelationship of end face and radial run-out values of controlled rotor surfaces from geometrical errors of its parts are presented.
Analytic design methodology for flexible wing parametrization and spanwise load estimation
Authors: Gueraiche D , Popov S , Benini E
Published: February 2021

Presented is an analytic study of aerodynamic loading along a high aspect ratio wing, typical for airliners, under passive aeroelastic deformation. Such a highly non-planar, curved wing is feasible using the latest composite material technology, and is expected to enhance airliners aerodynamic performance at transonic cruise conditions, given it allows lower induced drag, similar to a wingletted wing. Also, gust and manoeuvring loads can be partially alleviated by the structure elasticity, hence the concept is of great interest for the airliner industry. A major problem to designing highly flexible wings is their constantly shifting shape and, as a result, their hardly predictable, non-constant lift force generated. This paper provides an attempt to precisely estimate load distribution along the statically inflected wing at different stages of its deformation, using mathematical parametrization of the curved wing shape to relate its geometry to aerodynamic loading and structural stiffness in a closed form function. This is achieved using the geometric dependency of local angles of attack on local wing curvatures, therefore load distribution is a function of the parametrized deformed wing shape. Spanwise load distributions in turn can be coupled with structural stiffness distributions using cantilever beam theory.
Interaction and orientation of non-magnetic particles in magnetic fluid in magnetic and electric fields
Authors: Vegera Zh
Published: February 2021

In this article, the processes of structuring non-magnetic microparticles of various shapes (spherical and cylindrical) placed in magnetic liquid are investigated. It was established that the equilibrium orientation of non-magnetic microparticles and structural formations from them in magnetic and electric fields is determined by the ratio of both field strengths and magnetic and electrical parameters of the carrier medium and material of non-magnetic inclusions. Analysis of mechanisms of interaction of non-magnetic filler particles and orientation of formed structures under the influence of magnetic and electric fields was carried out. It has been found that the action of a uniform magnetic field on a magnetic liquid with a dispersed non-magnetic filler leads to a significant anisotropy of the thermal conductivity coefficient - the difference in the thermal conductivity coefficient in the direction coinciding with the field strength vector and perpendicular to it can reach 25%. The analysis of the detected effect is made on the basis of ideas about the occurrence of structural anisotropy in such a medium due to the structural organization of non-magnetic filler particles in the magnetic field.
Optimization of identification of non-stationary objects due to information properties and features of models
Authors: Jumanov I I , Xolmonov S M
Published: February 2021

Constructive approaches, principles, methods of optimal identification of random time series of non-stationary objects with mechanisms of using statistical parameters, dynamic characteristics, specific features, and data patterns are proposed. Models and algorithms for hybrid identification have been developed that combine the capabilities of statistical, dynamic models, and a three-layer neural network. Mechanisms for adjusting model variables are implemented, taking into account the structural complexity, stochasticity of links between the elements of the random time series, ambiguity of dynamics, a large number of variables, the impact of the external environment. In the solutions of optimization problems, probabilistic and soft computing, self-organizing, predictive, adaptive properties of neural networks and dynamic modeling are used. A generalized algorithm for the identification of non-stationary objects is built on the basis of the mechanisms for identifying segments, boundaries, the general interval of element values, the selection of informative elements, and the formation of a training set. A simplified computational scheme for identifying non-stationary objects is implemented on the basis of 4-order orthogonal polynomials, a cubic extrapolation spline function, a linear Kalman filter, and a three-layer neural network. A software complex for identification in the C ++ language in the parallel computing environment “CUDA” has been developed and implemented.
Aerospace engineering experience and on-board software projects of satellite navigation systems
Authors: Kovalev I V , Testoyedov N A , Koltashev A A , Efa S G
Published: February 2021

The main stages of creating global space navigation systems of the first generation are discussed in the article. The authors give a description of the scope and content of work, stages and timing of this work, and also give the main characteristics of the satellites and on-board software testing processes of these space navigation systems. The list and sequence of technological stages of the on-board software testing process are defined in the description of the methodology for guaranteeing the quality of development and maintenance of the on-board software of communication and navigation satellites.
Measurement information security when using mechanoluminescent sensor elements with distributed sensitivity in aerospace engineering
Authors: Tatmyshevskiy K V , Pavlov D D
Published: February 2021

Electromagnetic compatibility and protection of data transmission lines is currently one of the most important requirements for elements of modern technical devices. Especially should be considered the possibility of electromagnetic compatibility when introducing new sensors into operating technical systems. Fiber optic sensors, operating in generator mode and producing signals of an optical nature, are not susceptible to electromagnetic interference and do not emit interference into the surrounding space. Distributed mechanoluminescent pulse pressure transmitters belong to this type of sensors. One of the most important elements of this type of sensors is the transmission channel of the output optical signal. The analysis of the possibility of using fiber-optic harnesses for the transmission of measuring information is carried out.
Comparative study of local search in SWAP and agglomerative neighbourhoods for the continuous p-median problem
Authors: Kazakovtsev L A , Rozhnov I P
Published: February 2021

One of the classical NP-hard problems of location theory is the p-median problem. In this paper, we investigate the comparative efficiency of searching for a solution to this problem in SWAP-neighborhoods, as well as in new AGGL-neighborhoods, the concept of which is introduced in this paper. A higher comparative efficiency in AGGL-neighborhoods is shown, as well as the dependence of the search result on the neighborhood parameter, the selection of the optimal values of which requires additional research.
Information security aspects of virtual museums in Russia
Authors: Mityushin D A
Published: February 2021

Information technologies are entering the life of modern society by leaps and bounds, sometimes radically changing its image. The influence of information technologies on changing the cultural and spiritual space of many countries is perceptible too. A new phenomenon of modern culture has gone into society – the virtual museum, which has faced completely new problems that real museums have not experienced before. These problems are associated with ensuring the cyber security of virtual museums. The article discusses the features of virtual museums, their advantages and disadvantages compared with real ones. Special attention is given to the information security of virtual museums. The author has found a large number of research and publications deals with virtual museums. However, they practically do not touch on issues related to the cyber security of the object under study. Threats of virtual museums and attacks against ones are analyzed in the article. Security variants against threats are offered.
Building communication networks: on the application of the Kruskal’s algorithm in the problems of large dimensions
Authors: Melnikov B F , Terentyeva Y Y
Published: February 2021

The paper deals with the development of the topology of ultra-large communication networks, i.e. networks containing several thousand vertices. In this case, the coordinates of the vertices of the undirected graph are somehow predetermined and a set of edges must be constructed. The main point of the options we are considering for developing the network topology is the minimum of the sum of weights of the edges; however, we note in advance that this criterion of minimality is often not the only objective function in the practical problems we are considering. In our previous papers, two realistically considered tasks were formulated. However, everything is not so simple, and we cannot use the direct version of Kruskal’s algorithm. The complexity of this algorithm depends on the representation of the data, i.e. the data structures used. In our situation (when the number of considered vertices is approximately 5000 to 10000), the operation of a simple version of the algorithm takes about a half an hour, which, of course, is acceptable for a one-time solution to the problem under consideration, but it is unacceptable in the case when such solutions are constructed repeatedly (in particular, iteratively). Some temporary improvements to the practical operation of the algorithm provide different options for using complex data structures. The subject of this article can be formulated as follows. We are moving from exact algorithms (in particular, Kruskal’s algorithm) to some heuristics. Moreover, for the starting problem that we are considering, we cannot work without heuristic algorithm at all. However, we describe two specific variants of a simple implementation of Kruskal’s algorithm for problems of large dimensions; in our titles, those are “the 1st and the 2nd algorithms of the usual implementation”. We have formulated two heuristics (“the 3rd and 4th algorithms”). In our opinion, one of these algorithms turned out to be quite acceptable; we present some practical results of computational experiments. And it is very important that these two heuristics will be useful not only for such a “0-th problem”, but also for much more complex problems.
Forecasting steppe fires using remote sensing data of time series
Authors: Goryaev V M , Basangova E O , Goldvarg T B , Bembitov D B , Djachnaeva E N , Lidzhi-Garyaev V V
Published: February 2021

In fire monitoring systems, Internet of Things sensors allow predicting the area of fire in combination with machine learning. This article provides an insight into the use of machine learning models in predicting steppe fires. The work uses statistical methods for forecasting time series, methods of regression analysis and forecasting techniques. This project explores a data mining approach for predicting steppe fires. Several different data mining methods are considered and at least five different special methods of feature selection (spatial, temporal, Fire Weather Index components, weather attributes and our own developed classes). At the moment, data mining software systems have been tested on real data collected in the southern regions of Kalmykia. The study used open data from meteorological stations, our own database time series collected over the past 3 years, tested various data mining methods and at least five meteorological inputs, which will allow predicting a burnt area of small and medium fires, an area of dust storms, etc. The results show that the k Nearest Neighbor model is the most appropriate choice for the steppe fire forecasting model. The chosen model takes into account both meteorological data and images for early forecasting of FIRMS fires.
Technology of spacecraft on-board equipment design support
Authors: Isaeva O S
Published: February 2021

The Technology is shown that combines knowledge bases, information and graphic resources into a set of automated software tools. Technology includes the methods of intellectual models’ building and the tools of scenario creation for measurement, data transmission, test results’ control and visualization. It is implemented in the software-mathematical model of the on-board equipment control system and the software of the testing equipment. Software is integrated into a technological platform for the design and testing of technical systems. Application of Technology reduces the time of the on-board equipment design and production, reduces import dependency of Russian space development and increases its competitiveness in the space systems’ market.
UWB locating system in semi-open space
Authors: Krasnov T V , Sharshavin P V , Baturin T N , Tokarev R I , Novikov A V
Published: February 2021

Simulation of the processing of navigation signals and estimation of the noise immunity of the receiver of an ultra-wideband positioning system in difficult conditions for receiving GNSS signals with dense taiga vegetation was performed. Experimental data were obtained on microwave interference and the conditions for the propagation of radio waves at real production facilities, including operating mountain taiga geophysical profiles.
Indoor ultrasonic positioning system for mobile objects
Authors: Morohin D V , Totsky A A
Published: February 2021

At present, automation of many types of works is widely distributed. When solving the automation problem, it is often necessary to use methods for determining the position of individual parts of an industrial or other system, as well as controlling the moving elements of such a system. In the paper, one of the variants of solving such a problem is considered. The determination of the object coordinates is calculating from the computed distances to known points. There are several ways to implement this method. Authors offer a solution that provides real-time control of the mobile device, automatic location control and delivery of the moving part of the system to a specified point with high accuracy. The system provides scalability for solving the problem of positioning in various rooms.
An algorithm for generating consistent decision rules for assessing template diagrams
Authors: Trebukhin Alexey G , Filatova Natalya N , Sidorov Konstantin V
Published: February 2021

The authors consider an algorithm for generating consistent decision rules for choosing a rational alternative from a set of automation system functional diagrams using the mathematical apparatus of fuzzy logic and rough set theory. The algorithm enables a multicriteria assessment of complex diagram variants without a noticeable increase in time complexity compared to the assessment of single-loop diagrams. The paper formulates the requirements for training sets of functional diagrams, taking into account the characteristics of their circuits and application areas. The use of the algorithm simplifies the development of automation diagrams for technological objects and allows improving the quality of their design solutions.
Stochastic regulation of the technological aggregates
Authors: Kosarevskaia S A , Shukalov A V , Zharinov I O , Zharinov O O
Published: February 2021

The problem of stochastic regulation used in technological units to control equipment is investigated. Stochastic control takes into account the random nature of the data sample that statistically characterizes the accuracy and stability of automatic processes. Stochastic regulation is performed in the working area of the technological unit and at the level of the cloud containing mathematical tools for analyzing signatures. Data exchange at various levels of control is implemented in a telecommunication network built on the principle of the wireless Internet of Things. The structure of the basic element (technological unit) of cyber production is given. The mechanisms of network communication of technological units and the principles of network-centric control that are relevant for stochastic control are described. It is shown that defect-free automatic control of cyber-production uses algorithms that form the basis of machine learning methods. The advantages of computer-synthesized control of the mechanization of cyber-production by means of communication tools of the Internet of Things are described.
Using genetic algorithms for operational planning of cement mills loading
Authors: Svetlichnaya V I , Savkova E O , Shumaieva O O , Chengar O V , Shevchenko V I
Published: February 2021

The article discusses the problem automating the construction of schedules for cement production. The necessity using a computer system for planning the loading of technological equipment is substantiated in order to develop the optimal use of available resources for the timely and high-quality execution production tasks. The essence of the problem is shown, which is to allocate resources (cement mills and produced brands of cement) the production system for a given target plan so as to exclude deviations the real plan from the target, as well as to reduce the number of mill switchings to a minimum. The formalization the task planning the loading the mills is carried out and those essential parameters of the process are given, which are selected as the initial data for solving the task planning the operation of grinding mills. The solution to the problem constructing schedules for the operation of cement mills is based on the use of a genetic algorithm, for which an implementation sequence is proposed. The results solving the problem are also presented, which confirm the correctness the chosen method and its implementation.
The main directions of smart lighting systems development as one of the ways to improve energy efficiency
Authors: Kolomiets V I
Published: February 2021

The aim of the research was to study and generalize the directions of smart lighting systems development as one of the ways to increase energy efficiency. To obtain statistical data, the Elsevier publisher’s Scopus database was used. In order to assess the relevance and significance of research in this area, the work provides statistics of publications over the past five years. As a result, the main directions of smart lighting systems development were identified, aimed at using smart lighting systems as the basis for organizing Smart City services.
On the identification of bearings of active interference sources
Authors: Trofimets E N , Mazakov E B , Trofimets V Ya
Published: February 2021

The features of bearing information processing in a two-position radar system are considered. It is shown that in these systems, due to the absence of redundant information, the identification of bearings is a multi-alternative problem of statistical selection of hypotheses, the solution of which is especially important when locating a significant number of sources of active interference. The analysis of the matrix of coordinates of intersections of azimuthal bearings is carried out, a rule for identifying possible hypotheses of identification is formulated. To reduce the a priori uncertainty in the identification of bearings, it is proposed to use the energy differences of interference signals.
The unit of cubic matrices in modeling of micro-relief
Authors: Belkin E A , Poyarkov V N , Markov O I
Published: February 2021

The apparatus of cubic matrices allows us to give a classification of the contiguous cuboid. Invariant theory is used for this purpose. A cubic matrix is a generalization of the concept of a square or rectangular matrix. Increasing the dimension of a square matrix by one requires a new definition of the product of three-dimensional matrices. It is necessary to search for new invariants for the operator of parallel transfer of the coordinate system and the operator of rotation around the origin. The contiguous cuboloid allows us to give a three-dimensional geometric model of the microrelief an order of magnitude more accurately than the contiguous paraboloid does. The geometrical structure of the contiguous coboloid is investigated by the method of sections. The curvature of the surface at the point of contact with the cuboid is estimated by the curvature tensor, which is analogous to the Riemann-Christoffel tensor. The curvature of the surface in the local area of the point of contact is estimated with certain assumptions. There is no more precise geometric object that defines the curvature of the surface.
Computer-aided manufacturing: Industry 4.0
Authors: Kurasov D A
Published: February 2021

The modernization of the Russian economy and its transition to an innovative development path are inextricably linked with the renewal of production and its material and technical base. In recent years, there has been a tendency to increase the economic potential of highly developed countries through scientific, technological and technological innovations, with the State playing an active role. There is a trend towards a digital industry based on the so-called Industry 4.0. This leads to massive implementations of cyber physical systems in production, to the automation of most production processes, the endowment of devices with artificial intelligence and the introduction of many other modern technologies. All this has a significant impact on increasing productivity and reducing the cost of production.
Numerical study of the combustion of a flat layer of methane gas hydrate
Authors: Davletshina M R , Gimaltdinov I K , Stolpovsky M V , Akchurina V A
Published: February 2021

In the work in a flat-one-dimensional formulation, a mathematical model and the results of modeling the combustion process of a gas hydrate as a result of its ignition with a mixture of methane and an oxidizer are presented. It was assumed that the rate constant of a chemical reaction depends on temperature according to the Arrhenius law. The solution was carried out by a numerical method based on the method of catching the phase transition front into the nodes of the spatial grid. On the basis of the obtained solutions, the distributions of the main parameters of the system, as well as the dependences of the highest temperature of the gas mixture and the rate of decomposition on time, were constructed.
The use of airlift during drilling of technological wells
Authors: Karmanov T D , Kaliyev B Z , Assanov N S
Published: February 2021

The article describes new drilling methods recognized as testing works in the drilling company “Volkovgeologiya” JSC. A special feature of this method of drilling is the introduction of the airlift principle. The proposed technology differs in that it is applicable during well drilling and does not require investments for reconstruction, which is significantly reflected in the number of repair and restoration works. With a wide application of this method, the possibility of providing a huge economic effect in the operation of technological wells is described.
Influence of the initial turbulence of the air suspension flow on the speed and limits of flame propagation
Authors: Egorov A G
Published: February 2021

The paper presents experimental data on the effect of the initial turbulence of the air suspension flow of aluminum particles on the speed and limits of flame propagation. It was found that when installing the grate, depending on the diameter of the chamber and the size of the aluminum particles, the flame propagation speed can either increase or decrease. In the flow of air suspension of aluminum particles ASD-1, a simultaneous increase in the intensity and scale of turbulence leads to an increase in the flame velocity and expansion of the flame propagation limits.
The prospects of using of flywheel energy accumulators in the lifting and transport industry
Authors: Barbashov N N , Barkova A A
Published: February 2021

The increase in the energy consumption of lifting and transport machines in transient operating mode requires the creation of mathematical models and, on their basis, the development of recommendations for increasing economy. Important reasons for reducing the economy of lifting machines are changes in speed and load, deviations from the optimal value and causes an increase in energy dissipation. Another reason for the increase in lost energy is the process of machines with a loss of kinetic energy during their shutting-off. Increasing the economic showings of machines is possible by reducing its nominal power, which leads to a deterioration in dynamic qualities. A promising method of increasing the economy of machines is using of braking energy recovery, its accumulation and using during further acceleration. In this case, the increase of efficiency occurs without reducing the dynamic qualities and showings of the machine.
Improving the construction of grinding disk mill for producing fibrous semi-finished products
Authors: Vititnev A Yu , Alashkevich Yu D , Chistova N G , Marchenko R A
Published: February 2021

The article states that grinding is the most important process; it determines the efficiency characteristics of the fibrous semi-finished product and the properties of the products made of it. The effectiveness of this process is influenced by some factors, but a tackle is of the most importance. Recently, the issues of selecting and creating the tackle design for wood fibers preparing, in contrast to cellulose and waste fibers, remain significant. In this regard, a scientific approach to solving the issue of creating the tackle design is required for the effective preparation of high-quality wood fibrous semi-finished product. The article presents theoretical studies for efficient evaluation of the existed structures for grinding wood fibers in disk mills. It has been a basis for developing a new geometry of the tackle and predicting its efficiency along with numerous preliminary studies and investigations carried out by various authors. The results of the experimental studies of the grinding process applying the existing structure and the results of the simulated experiment with the developed geometry of the tackle are presented. A comparative analysis of the influence of the design features of various types of tackles on the dimensional and efficiency characteristics and fractional composition of the semi-finished wood fibers was carried out. It was carried out on the basis of the theoretical and experimental studies, as well as the results of other authors studies concerning a grinding process and the influence of the of the semi-finished product features in the preparation of a fibrous semi-finished product in a disk mill.
Magnetic fluid phase separation in an electric field
Authors: Vegera Zh
Published: February 2021

The phase separation and structural organization of a thin layer of a magnetic fluid under the influence of a constant electric field are investigated. It is shown that the action of an electric field leads to the appearance of labyrinth structures in a thin layer of a magnetic fluid, which subsequently leads to the formation of a free charge at the boundary of this layer with the rest of the liquid volume. The results of the study of the current strength on the shear rate dependence made it possible to estimate the value of the surface charge density and the time of its formation in the near-electrode space. By artificially increasing the electrical conductivity of the initial magnetic fluid, it is shown that the formation of labyrinth structures in a magnetic fluid in an electric field occurs at a certain critical value of its electrical conductivity.
Modeling of electrochemical machining by point electrode tool with a jump anode potential change
Authors: Zhitnikov V P , Zaytsev A N , Sherykhalina N M , Zhitnikova N I
Published: February 2021

The distribution of the electric field in the electrolyte near the contact point of two detail parts with different values of the anode potential is investigated. The problem is relevant in connection with the development of technologies for welds machining in order to dissolve material layers that retain residual tension and do not create new tension. The methods of the theory of functions of a complex variable are used to solve the problem, since a stationary electric field with the properties of solenoidality and potentiality is considered. A singularity of the complex potential at the contact point is found by the method of conformal mappings. The solution of the problem is sought as the sum of a known function with a singularity and a function without singularities, which is defined as a power series with unknown coefficients. The coefficients are determined numerically by the collocation method, i.e. the problem is reduced to solving of equations system. The Gauss method is used for this purpose. The problems with the specified dependence of the anode potential on the current density is solved. The errors estimates have shown that by the developed method allows determining the desired parameters with sufficient accuracy. The distributions of the anode potential and components of strength on the surface of the detail are found. The resulting forms of stream lines allowed us to adequately describe the electric field which is the result of the superposition of the field of a point source and the field arising from the potential difference in different parts of the detail.
Impact of CVD-synthesis parameters and film thickness on growth rate of single-crystal diamond
Authors: Maslov A L , Polushin N I , Laptev A I , Martynova T V , Grechikhina A M
Published: February 2021

The widespread use of CVD-reactors of various constructions and the influence of many factors on the formation of energy-saturated reaction zone has led to the fact of significant difference of technological parameters optimal for each reactor even of one brand. An economically important parameter, in addition to the quality of the obtained single-crystal diamond layer, is the growth rate, which depends on many factors: the flow rate and chemical composition of gases, pressure in the reaction chamber, substrate temperature, the shape of the formed plasma cloud, dimensions and shape of molybdenum substrate holders and et al. This work is devoted to the experimental determination of the single-crystal CVD-diamonds growth rate across various synthesis conditions on Ardis 300. In research, we shown the effect of the thickness of the synthesized diamond layer on the rate of formation of subsequent diamond layers, which is associated with a change in the degree of misorientation between the crystallographic plane (100) and direction [100]. Also, this can be associated with an increase in the roughness of the growing surface, leading to an increase in the specific number of active centers thermodynamically favorable for carbon deposition during the formation of the crystal structure of diamond.
RES-powered charging stations for electric vehicles
Authors: Volkov S , Sidorova V , Orlov A , Ostashenkov A
Published: February 2021

The paper provides a comparative analysis of the structure of energy consumption and production in the countries of the European Union and Russia. It is shown that Russia is a promising country for the effective development and implementation of renewable energy sources. A block diagram of a charging station for electric vehicles, which will be powered by photovoltaic panels, is proposed. Unclaimed electricity in this case can be sold to the external network or smooth the load curve of the nearest transformer substation.
Effect of deposition current density on the Co–Ni/SiO2 alloy composite coatings using scanning jet electrodeposition
Authors: Jiang Wei , Qiu Mingbo , Shen Lida , Lou Guibin , Yang Xuegeng , Eckert Kerstin , Tian Zongjun
Published: February 2021

Co–Ni/SiO2 alloy composite coatings were electrodeposited on copper substrate by scanning jet electrodeposition at various current densities to study its effect on the morphologies, texture orientation, microhardness, adhesion force, wear resistance, and corrosion resistance of Co–Ni/SiO2 alloy composite coatings. The structure and performance of the material were characterized using a scanning electron microscope, XRD diffractometer, nanoindentation, scratch tester, friction and wear tester, and electrochemical methods. The morphologies of the Co–Ni/SiO2 alloy composite coatings changed from sparse and slender structures to dense starfish structures with an increase in current density. A part of Co precipitated in the form of a face-centered cubic structure and formed a solid solution with Ni, while another part of Co precipitated in the structure of the composite coating in the form of a hexagonal close-packed structure. The Co–Ni/SiO2 alloy composite coating exhibited excellent adhesion force, wear resistance, and corrosion resistance when the deposition current density was 130 A dm−2. Once the current density was exceeded, some microcracks appeared on the surface of the composite coating, after which the adhesion force and corrosion resistance decreased. The present study suggests that current density at 130 A dm−2 is more suitable than low current density for jet electrodeposition to prepare high-density and high-quality composite coating.
Effect of TiC content on the microstructure and properties of large-area laser-cladded TiC Ni-based composite coatings
Authors: Demin LI , Xiaofeng Sun , Zhanming LI , Wei Song , Huaxing Zhao , Peng Song , Biju Zheng
Published: February 2021

The study of effect of TiC content (10%, 20% and 30%) in Ni-matrix on the microstructure and properties of composite cladding prepared by laser cladding was reported in the present. Developed clads were characterized by SEM, EDS, XRD, microhardness tests, friction and wear tests and electrochemical tests. The experimental results show that the TiC/Ni composite coating had good quality and strong metallurgical bonding with the substrate. As the TiC content increases, distribution of TiC densified, the grain size increased, and the average hardness of the coating increased to 667.87 HV0.2, which is approximately three times that of carbon steel. Moreover, as the TiC content increased, the friction coefficient of the coating decreased gradually. However, the friction coefficient of the 10% TiC coating was the most stable, as wear time increased. The electrochemical results showed that the corrosion resistance of the 10% TiC coating was the best. As TiC content increased, the corrosion resistance of the composite coating first decreased and then increased.
Optical and electrical characterization of WS2 multilayer on flexible PET substrate
Authors: Handayani I P , Utama A M , Rosi M , Rafli A M , Setiawan A
Published: February 2021

WS2 is two-dimensional layered material which the electronic band gap is dependent on the number of layers. From application point of view, the WS2 few layers are good candidate for nano scale flexible electronics . In this study, the WS2 number of layers is modified using liquid phase exfoliation method. The blue shift of WS2 supernatant absorption peaks suggested the change of layer thickness compare to the non-exfoliated one. This supernatant is further deposited on Polyethylene terephthalate (PET) to create a flexible multilayer WS2 thin films. The morphology and the content of the thin film are confirmed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS), respectively. The Raman and photoluminescence spectroscopy show typical characteristics of WS2 multilayers which are dominated by W-S vibrations, exciton contributions, as well as the local defect and strain effects. Furthermore, the electrical characterization reveals the robustness of the WS2 electronic properties again the mechanical stretching. This study highlights the abundant optical and electrical characterization of WS2 multilayer which are applicable for flexible electronic devices.
Superconductivity found at 15 °C
Authors: Johnston Hamish
Published: February 2021

Researchers have created a material that can superconduct at room temperature under high pressures, as Hamish Johnston discovers
Jupiter-sized planet found orbiting tiny white dwarf star
Authors: Johnston Hamish
Published: February 2021

A huge planet about the size of Jupiter has been spotted orbiting a tiny white dwarf star 80 light-years away.
Upper limit found for speed of sound
Authors: Cartlidge Edwin
Published: February 2021

Researchers have discovered that the speed limit for sound can be defined by fundamental constants, as Edwin Cartlidge reports
Cosmic pioneers bag Nobel prize
Authors: Banks Michael , Johnston Hamish
Published: February 2021

Roger Penrose, Reinhard Genzel and Andrea Ghez win award for their work on black holes, as Michael Banks and Hamish Johnston report
Climate change threatens astronomy observations
Authors: James Chaneil
Published: February 2021

Rising global temperatures could worsen seasonal El Niño events and cause telescope images to lose their quality.
Concerns over impact on radio astronomy of satellite constellations
Authors: Makoni Munyaradzi
Published: February 2021

The large number of planned satellites for telecommunication poses an “extremely worrying” threat to radio astronomy and specifically the fledgling Square Kilometre Array (SKA).
Keeping up with opportunities
Authors: Duffy Caitlin
Published: February 2021

Caitlin Duffy says it is more important than ever to consider your next career move despite the challenges posed by the COVID-19 pandemic
A quantum future
Authors: McKenzie James
Published: February 2021

With a new era of quantum technology beckoning, James McKenzie reflects on recent milestones in the quantum computing “arms race”
The bank of success
Authors: Crease Robert P
Published: February 2021

After helping to set up the first major repository of protein structures 50 years ago, Helen Berman is now significantly expanding its scope, as Robert P Crease finds out
Nobel lessons
Authors: Palmer Tim
Published: February 2021

Roger Penrose’s award of one half of the 2020 Nobel Prize for Physics should send an important message to science policy-makers.
Rab14/MACF2 complex regulates endosomal targeting during cytokinesis
Authors: Gibieža Paulius , Peterman Eric , Hoffman Huxley K. , Van Engeleburg Schuyler , Skeberdis Vytenis Arvydas , Prekeris Rytis
Published: February 2021

This study shows that Rab14 regulates the efficiency of recruiting Rab11-endosomes to the central spindle microtubules and that Rab14 knockout leads to inhibition of actin clearance at the abscission site. Finally, it demonstrates that Rab14 binds to MACF2 and regulates targeting of endosomes to the central spindle.
Comparison of Viscoelastic Testing by Rotational Torsion and Harmonic Resonance Methods
Authors: Pham Huy P , Azad Ameneh , Gounlong Jenny , Gutierrez Jocelyn , Mikrut Krzysztof , Miller Jonathan L , Wool Geoffrey D
Published: February 2021

Objectives

To compare the performance of the TEG 5000 and TEG 6S Global Hemostasis cartridge.

Methods

We reviewed validation data of the TEG 5000 and TEG 6S Global Hemostasis cartridge. The specimens were analyzed in parallel according to the manufacturer’s operating instructions.

Results

Fifty-four healthy donors and 13 donors with known hemostatic abnormalities were included. The correlations between instrument types were only moderate—the Spearman rank correlations were 0.55, 0.62, 0.64, and 0.72, respectively, for CK R, K, angle, and maximum amplitude (MA) parameters. Using the manufacturer’s device-specific reference ranges to classify results as normal/abnormal, there was weak agreement in the qualitative interpretation of all parameters (Cohen’s κ for agreement for CK R, K, angle, and MA was 0.418, 0.154, –0.083, and 0.127, respectively). This could lead to discordant transfusion decisions.

Conclusions

These findings indicate that the TEG 5000 and TEG 6S may not be used interchangeably.
Excellence Available Everywhere
Authors: Mirza Kamran M , Gonzalez Raul S , Jiang Xiaoyin “Sara” , Khanafshar Elham , Wobker Sara E
Published: February 2021

Objectives

The goal is to describe the use of a virtual platform in the delivery of Virtual Pathology Grand Rounds (VPGR) and discuss the overall experience from the perspective of hosts, speakers, and participants.

Methods

Zoom was a natural choice for an online format because virtual platforms had been increasingly used to conduct meetings and medical education. VPGR hosted 14 speakers on a variety of topics, including subspecialty anatomic pathology material, digital pathology, molecular pathology, and medical education.

Results

There were 221 registrants and 114 participants for the first lecture, reaching a maximum of 1,268 registrants for the 12th lecture and the maximum limit of 300 participants during 3 lectures. Speakers stated that VPGR conveniently provided career-building opportunities through partnerships with host universities and remote attendance. Participants identified a lack of interpersonal communication and technical challenges as downsides.

Conclusions

VPGR serves as strong proof of concept for the feasibility and demand for high-quality, remote academic pathology talks.
Comparing Parametric, Nonparametric, and Semiparametric Estimators: The Weibull Trials
Authors: Cole Stephen R , Edwards Jessie K , Breskin Alexander , Hudgens Michael G
Published: February 2021

We use simple examples to show how the bias and standard error of an estimator depend in part on the type of estimator chosen from among parametric, nonparametric, and semiparametric candidates. We estimated the cumulative distribution function in the presence of missing data with and without an auxiliary variable. Simulation results mirrored theoretical expectations about the bias and precision of candidate estimators. Specifically, parametric maximum likelihood estimators performed best but must be “omnisciently” correctly specified. An augmented inverse probability–weighted (IPW) semiparametric estimator performed best among candidate estimators that were not omnisciently correct. In one setting, the augmented IPW estimator reduced the standard error by nearly 30%, compared with a standard Horvitz-Thompson IPW estimator; such a standard error reduction is equivalent to doubling the sample size. These results highlight the gains and losses that can be incurred when model assumptions are made in any analysis.
Rationale and Design of a Cluster Randomized Trial of a Village Doctor-Led Intervention on Hypertension Control in China
Authors: Sun Yingxian , Li Zhao , Guo Xiaofan , Zhou Ying , Ouyang Nanxiang , Xing Liying , Sun Guozhe , Mu Jianjun , Wang Daowen , Zhao Chunxia , Wang Jun , Ye Ning , Zheng Liqiang , Chen Shuang , Chang Ye , Yang Ruihai , He Jiang
Published: February 2021

BACKGROUND

In China, hypertension prevalence is high and increasing while the control rate is low, especially in rural areas. Traditionally, village doctors play an important role in infectious disease control and delivering essential health services to rural residents. We aim to test the effectiveness of a village doctor-led multifaceted intervention compared with usual care on blood pressure (BP) control and cardiovascular disease (CVD) among rural residents with hypertension in China.

METHODS

In the China Rural Hypertension Control Project (CRHCP), a cluster randomized trial, 163 villages were randomly assigned to the village doctor-led intervention and 163 villages to control. A total of 33,995 individuals aged ≥40 years with an untreated BP ≥140/90 mm Hg or treated BP ≥130/80 mm Hg or with an untreated BP ≥130/80 mm Hg and a history of clinical CVD were recruited into the study. The village doctor-led multifaceted intervention is designed to overcome barriers at the healthcare system, provider, patient, and community levels. Village doctors receive training on standard BP measurement, protocol-based hypertension treatment, and health coaching. They also receive technical support and supervision from hypertension specialists/primary care physicians and performance-based financial incentives. Study participants receive health coaching on home BP monitoring, lifestyle changes, and adherence to medications. The primary outcome is BP control (<130/80 mm Hg) at 18 months in phase 1 and CVD events over 36 months in phase 2.

CONCLUSIONS

The CRHCP will provide critically important data on the effectiveness, implementation, and sustainability of a hypertension control strategy in rural China for reducing the BP-related CVD burden.

CLINICAL TRIALS REGISTRATION

Trial Number NCT03527719.
Literary Agency
Authors: McGrath Laura B
Published: February 2021

This essay is one part documentation and one part provocation, with a simple goal: to acknowledge the agency of the literary agent. There is no figure more significant to contemporary literary production and less studied by scholars than the agent. Drawing on ethnographic interviews conducted with 28 literary agents over the course of four years, I argue that agents shape the form and content of contemporary fiction by acting as administrators of the logic of the marketplace, conditioning their clients to write in and for the international multimedia conglomerates known as the Big Four. I take the agent’s list to be one of the central organizing heuristics of the contemporary literary field and read the list of one agent, Nicole Aragi, to examine what I call “corporate taste”: personal aesthetic judgments carefully calibrated to anticipate and respond to the demands of publishing conglomerates.

Agents calibrate their aesthetic judgments to anticipate and respond to the demands of publishers and the market, becoming administrators of the logic of the corporation, thus shaping the form and content of contemporary fiction.