bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of information technology in national security
Authors: Yeganegi Kamran , Arbabi Zahra , Ibrahim Hussein Asma
Published: May 2020

The use of information and communication technologies has been increasing day-today throughout the world since the 1980s, as these technologies seem to reduce the complexity of issues for governments and at the same time reduce the context. Provided for the complex interdependencies between governments. This dual function of information and communication technologies has caused security problems for countries, especially underdeveloped countries, in terms of lower access or, in other words, the digital divide of advanced countries. The growing challenge in the security of nations is a major concern for everyone, in order to tackle this challenge a great amount of effort must be dedicated. Multiple related questions are asked in this article: Are we capable of IT and Ensure Homeland Security Strategy in Different Countries Do Intelligence Agencies Have the Right IT Infrastructure for the Purposes of Collecting, Sharing, and Disseminating Information? Is there Enough Monitoring Equipment? Information technology plays a significant role and will continue to strengthen the national security against future upcoming threats and cyber-attacks. Particularly, information technology can help countries to identify potential threats, share information easily, and protect mechanisms in them. Provide and develop capabilities.
The Impact of the Use of the Strategy (the five steps) Modified (SQRRE) in the Achievement of Students in the Fifth Grade in Mathematics
Authors: Al-Ubodi Dr. Ahmed Hamzah Abed
Published: May 2020

The current research aims to amend the strategy (five steps) to adapt it to the mathematics of the students of the fifth grade of primary and to know the impact of the modified strategy on the achievement of the fifth grade students in mathematics. The strategy of the five steps or the so-called Robinson model was used, the sample consisted of (76) female students from Al-Tabarsi Primary School for Girls with two groups. The first group was experimental with 38 students. The second group was control with 38 students. The sample was selected randomly, the search tool was the achievement test was to make sure his psychometric properties, has been the use of the alpha Cronbach equation and test (t) for two independent samples of statistical means, and the results showed.There were statistically significant differences in the achievement test for the two research groups and for the experimental group which was taught according to the modified five steps strategy. By the results, a set of recommendations were written.
FGM Copula’s Extension Via Polynomial Function
Authors: Al-Adilee Ahmed , Mohammed Mahdi Ali
Published: May 2020

This study is concerned with generalizing the well-known family of FGM copula in terms of a polynomial function. A general form of the FGM copula via a copula function is proposed in order to obtain a new FGM copula family. Various particular cases have been presented according to the degree of the polynomial function. Proofs of necessary and sufficient conditions of the created copulas have been explained so that we guarantee that the desire function is copula. We firstly propose and define a general form that associate the FGM copula with a polynomial function. Graphs and some extra properties are presented as explanatory tool of some degrees of the obtain copula. Finally, we present some important calculations related to the most popular dependences by means of the FGM copula extension.
Optimal Design, Simulation and implementation of Solar Photo-voltaic Panels in Hybrid electric vehicles using CATIA V5R19 software integrated with ANSYS 13.0 versions
Authors: Sharma Shubham , Obaid Ahmed J.
Published: May 2020

The primary motive of this research investigation is to explore out by enforcing the sun powered energy in the present hybrid electric vehicles, which signifies precipitous plummet in pollutants and harmful contaminants of environment. Solar powered coercing vehicles are environmental friendly however can’t attain to most reliable speed in certain specific time-interval. The operational functioning of two dissimilar fuels collectively may be one of the most advantageous aspects of this novel concept. CATIA V5R19 is appropriate podium for the design outlining of vehicles which this particular research study is aiming. After analyzing the blueprint layout, for computation or estimating of forces, load, internal resisting force and lateral strain performing at the front and rear collisions of structural body-on-frames, ANSYS 13.0 version platform was utilized for software primarily based modeling and simulation. Output statistics or facts figures are premeditated to determine the technical factors of solar powered hybrid vehicles. Solar hybrid electric vehicles have high competencies of an overall recital as its enormous arrangement of traditional fuel engine, possesses high powered electric-vehicle-battery & solar photo-voltaic panel modules.
Three band absorber design and optimization by neural network algorithm
Authors: Shawkat Shihab A. , Saeed Lateef Al-badri Khalid , Al_Barazanchi Israa
Published: May 2020

In this study, multi band absorber design based on signal absorbing metamaterial. After the metamaterial structure has been designed, the split gap is optimized by the neural network algorithm to get optimum absorption. By this way, metamaterial MTM absorber for stealth applications design has been created. In the simulation, the MTM signal absorbing was found to have three excellent absorption bands at x-band 8.41 GHz, 9.73 GHz, and 12.1 GHz with absorption level 91.65%, 99.35%, and 96.6% respectively. When the increasing the split gap diminution lead to nonlinear change in absorption level additionally resonance frequency. This proposed structure can be used as a multi band absorber application, stealth applications, and energy harvesting.
Hydrothermal Synthesis of Cu2ZnSnS4 Nanostructure and Their Application as H2S Gas Sensor
Authors: Ali Zainab S.
Published: May 2020

In this study, Cu2ZnSnS4 (CZTS) nanostructure are successfully synthesized by using hydrothermal method. Structural, morphology, optical properties have been studied for thin films (CZTS) deposited via spin-coating method. X-ray diffraction show that the films have pure tetragonal-kesterite structure preferred orientation along (112) . The FE- SEM shows that (CZTS) have a nano-sphere like structure, consist with diameters less than 35 nm. UV-Vis spectroscopy measurement showed that absorption coefficient (α <104 cm−1) and the band gap energy is equal to 1.42 eV. The Sensitivity properties of (CZTS) samples for H2S gas was tested at various operating temperature and found that the highest sensitivity is (83.63 %) at T=150 ºC.
Simulation Design of Hollow Core Photonic Crystal fiber for Sensing Water Quality
Authors: Muhammed N F , Mahmood A I , Kadhim Sh A , Naseef I A
Published: May 2020

In this work we submit a simulation design to sense the water quality using hollow core photonic crystal fiber. The work of this types of optical fibers depending on the variety of structural design and geometrical parameters. The numerical results are studied by using the Finite Element Method (FEM) through COMSOL MULTIPHYSICS simulation software. Different concentrations from (0%) to (100%) of D2O and H2O2 solution in water as sensed liquid had been chosen. The studied HC-PCF investigated for analyzing the relative sensitivity, effective area and confinement loss at wavelength range from (1) µm to (2) µm.
Chaos Generation Utilizing Optical Feedback Technique with Modern Applications
Authors: Naser Hayder A , Mousa Salam K
Published: May 2020

This overview summarizes the physical interpretation of chaos phenomenon and the most fundamental principles of Laser chaos generation by using optical feedback technique, the significant characteristics of deterministic chaos technique are mentioned with the moves from ordered state to the chaotic state. The description of the semiconductor lasers used to generate this phenomenon is studied with the multiple instances of laser performance before and after reaching chaos. The most important contemporary applications of chaos are in secure communication and Secure transmission digital images. The first section in your paper
Effect of Annealing on Copper Oxide Thin Films and Its Application in Solar Cells
Authors: Hussain Afnan N. , Hassoon Khaleel I. , Hassan Mustafa A.
Published: May 2020

Cupric Oxide (CuO) thin films were prepared by chemical spray pyrolysis (CSP) method at 400°C on glass and p-type Si substrate and then the films were annealed at 500°C and 600°C. The structural, optical and electrical properties of the thin films are measured. The analysis of X-ray diffraction (XRD) has confirmed amorphous phase mixed with polycrystalline features in the form of monoclinic structure. However, the polycrystalline CuO disappeared and changed to crystallite phase with increasing of annealing temperature. The values of bandgap energy (Eg) of the films were calculated using the absorbance data recorded by a spectrophotometer (UV-VIS). The calculated Eg using Tauc plot was about 2.45 eV which increased with increasing of annealing temperature. CuO thin films with high conductivity have been used to fabricate a hetrojunction solar cell of CuO/p-Si at 600°C which give Rs = 111Ω, Rsh = 7kΩ and a conversion efficiency of 1.24×10−4%.
The Performance of High-efficiency Perovskite Solar Cell (PSC) by Using Capacitance Simulator
Authors: Ahmed Muhanad A. , Ahmed Emad H. , Sabri Mohammed M. , Abed Wathiq R.
Published: May 2020

Organic-inorganic perovskite-based solar cell fascinated researchers around the world with their immense interest. Since 2009, intensive work on photovoltaic perovskite systems reached efficiencies over 20% relative to silicon-based solar cells with a current efficiency of approximately 17%. The current research paper presents the suitable choice of solar cell materials such as hole transport materials, type of perovskite material, the electron transport layer among others. A photovoltaic device is then built using the chosen materials which are then investigated through simulations using the SCAPS 1D program to determine the effects that these layer materials have on the performance of the overall PV device. Simulation methods are also used to optimize the parameters of the constructed device such as the thickness of the electrodes, the hole transport layer and the light absorber material. The simulation results showed an efficiency of 20.34 % using gold (Au) contacts.
Design and Implementation of an Efficient Solar Tracker System
Authors: Nori Abbas F. , Mohammed Faisel G.
Published: May 2020

The world is highly interested in using solar energy as an alternative to fossil energy. Changing the shape of solar systems was adopted to improve its work efficiency. Although the solar tracker is made to be more efficient than the fixed solar system, the work to develop it is yet uncompleted. In this paper, the solar tracker system is used, which works by (LDR) sensors, microcontroller Arduino UNO for controlling the system, and DC motors. The extent of the impact of the solar tracker was studied with its work time. The worked electric circuit for the timer was run the system for one minute and shut-down the system circuit for 29 minutes, the comparison of the work of the tracker was done with a timer and without timer. Finally, according to the amount of gain and loss of energy, it was found that the energy gains about 96.25% from timer system only, and the lost energy from the solar panel because used the timer is about (0.238 to 0.475) % only. The workplace lies in (32o01’49.08” N, 44o22’21.83” E, in Iraq), in August, to real solar panel type.
Effective computations of module inverses with the Approximating k-ary GDD Algorithm by Ishmukhametov
Authors: Al Khalidi Arkan M.
Published: May 2020

Finite field calculations are used in modern cryptographic protocols for generating keys, encrypting and decrypting data, and building an electronic digital signature. The module inversing is necessary part of these calculations based on the extended Euclidean algorithm. Ishmukhametov developed a new algorithm for calculating the greatest common divisor of natural numbers called the approximat-ing algorithm which is a variant of the k-ary GCD Algorithm by J. Sorenson. In this paper we develop an extension version of this algorithm.
Communication by 16 scrolls attractors of Chua’s circuit
Authors: Shahatha Sattar A , Malik Mutasim I , Asi Eidan A , Jasim Huda A
Published: May 2020

This paper analyses the chaotic signals which are always broadband, and similar to noise but they are deterministic. In our paper, we use Chua’s circuit to provide a class of signals (chaotic signals) that can be used in different communications as carrier signals which masking the data. The synchronization feature that occurs between the systems are exploited in our work. On this basis, Chua’s chaotic circuits were synchronized and data was transferred between the two circuits. The data were hidden in the output of the first Chua’s circuit and transferred to the second chaotic circuit, then these data was showed after the merging between the two chaotic signals. We also doubled the number of Chua’s circuit’s scrolls for about 16 scrolls and showed that by increasing the number of scrolls, the reliability of data transfer was increasing.
Performance Analysis of Photovoltaic Cells at Varying Environmental Parameters and Solar Cell Precise Algorithm
Authors: Ali Ronak , Obaid Ahmed J , Rasheed Haroon
Published: May 2020

Start your abstract here…olar irradiation and the temperature affects the output of photovoltaic modules in great extent. Environmental and electrical parameters affect the photovoltaic (PV) output power. Environmental parameters like solar radiance and temperatures has major contribution in PV output power. This research gives the precise algorithm for PV system simulation in Matlab. This research gives the simulation of current, voltage and power on different solar radiance level and temperature values. For allowing interaction with power converter, therefore this is mandatory to illustrate simulation that is based on circuit for PV cell. Simulation blocks are similar to PV module and they are compatible with various crusytalline modules and different types of PV arrays. Concentrated photovoltaic systems are being operated at higher temperature than fixed PV setup, and system efficiencies and material properties has been affected with higher temperature. Hence, thorough understating of high temperature are very important. Misalignment and optics tolerances causes decrement in cell efficiency. As direct sunlight is used by PV system, therefore proper system design can reduce sensitivity to errors.
Influence Investigation of Rolling Bearing Test Conditions on the Informativity Assessment of their Technical Condition
Authors: Kudryavtseva I S , Naumenko A P , Odinets A I , Basakin V V
Published: May 2020

Establishing patterns of the relationship of informative diagnostic parameters signals’s and test modes and operation of rolling bearings is an urgent task of technical diagnostics. The determining factor in the use of certain methods for assessing the condition and bearings faults, as well as the use of certain informative diagnostic parameters, is their sensitivity to changes in the condition of the bearing or to the size and degree of the defect development. The paper presents the results of the dependence study of the rolling bearings vibration parameters on the test and operation conditions: the rotation frequency of the inner ring, axial and radial loads. Numerical values of the listed factors are obtained that are optimal for testing bearings at the input control according to the sensitivity criterion. The study was conducted in accordance with the provisions of the experiment planning theory. It has been established that the magnitude of the vibration parameters and the level of components at the frequencies of bearing defects depend on the speed of rotation in direct proportion and increase with the deterioration of the technical condition of the bearings. It was experimentally confirmed that axial and radial loads significantly affect the values of the controlled vibration parameters only when defects appear in the tested bearings.
Issues of constructing scanning hybrid 3D measuring heads for high-precision contact and non-contact coordinate measurements of product dimension
Authors: Leun E V
Published: May 2020

The article presents a model of mechanical contact of a spherical tip and a product with small forces according to elastic deformations (further – deformations) taking into account the appearance of material deformations in the gap between them along the perimeter of the contact zone in the form of so-called piles-up. Dependences are obtained that link the gap with the deformation and the piles-up size. A graph is constructed for these parameters, the general form of which is close to the function of a single jump ∼1(l-Rpile), where Rpile is the radius of the pile-up.

The developed design and operating principle of the scanning hybrid fiber-optical measuring head (FOMH) based on the use of a small-sized spatial light modulator in the form of a fiber-optic piezoscanner with the formation of scanning movements of the laser beam and the measurement of gaps between the tip and the product are described. The possibilities of providing high-precision measurements of laser beam deflection angles during scanning movements by using acousto-optic heterodyne interference measurement systems are considered.
A geometric model for following the intended trajectories from the pursuer to the target
Authors: Dubanov A A , Ausheev T V
Published: May 2020

This article describes algorithms simulating the trajectory of the intended movement from the pursuer to the target at any given time. In the previously considered models of adaptive behavior, the pursuer and the target analyzed the coordinates of the opponent in the game and made an automatic decision where to move. In the models described in this article the behavior of the pursuer is determined by the location of the intersection point of the radius circle equal to the discrete step of the target and the assumed simulated trajectory at a given time.
Geometric method for researching the robot service area under the obstacles for the limitations on links movement
Authors: Pritykin F N , Nefedov D I
Published: May 2020

The work is devoted to solving one of the problems of robot motion virtual simulation using computer graphics. The paper offers a method for studying the shape and position of the work envelop of manipulator mechanisms in the presence of restricted work envelopes in the workspace. The method for determining the work envelope is based on the construction of allowed configuration of robot mechanisms. A parameter describing the structure and maneuverability index in different parts of the work envelope is proposed. The construction of cross sections of service areas for different positions of restricted work envelopes allows determining the areas where the output link centers of various mechanisms can not be located. The conducted research makes it possible to place the trajectories of the output link in solving motion problems, which reduce the probability of deadlocks in the automated motion synthesis along the velocity vector.
The Axle Box Generator Efficiency Determination Using A Scalar Frequency Controlled Induction Electric Drive
Authors: Lysenko O A , Songin M V , Simakov A V
Published: May 2020

The article discusses a method for determining the axle box generator efficiency. The generator is installed in the axle box of the freight car. It is driven by a wheels pair. The axle box generator provides power supply to freight car systems: diagnostics, geolocation and telemetry. To determine the efficiency, an indirect method of determining the mechanical power transmitted to the axle box generator is considered. The electromagnetic torque is determined through the induction electric drive model parameters of the generator. The article describes an experimental unit. It consists of a test generator, an induction electric drive, and an open platform frequency converter. The converter control system was created in MexBios Development Studio software. Oscillograms of generator tests are presented.
Thermal energy recovery efficiency improvement of gas turbine technology
Authors: Paramonov A M , Rezanov E M
Published: May 2020

The research relevance on improving the thermal energy recovery efficiency of gas turbine technology is caused by the need to reduce the fuel and energy consumption when generating the electric energy. The research objective is to define the technically and economically feasible heat recovery ratio of exhaust gases after gas turbine in the heat regenerator. The optimization problem of the heat potential recovery process was solved. The algorithm to calculate the optimal temperature of heating the air supplied to the combustion chamber of the gas turbine unit was developed. Methods of mathematical modelling of heat exchange processes, methods of choosing the rational option in solving the optimization problem, and mathematical methods of solving the optimization problems were used in the paper. The influence analysis of the optimal air temperature required for burning the fuel in the combustion chamber on the technical and economic efficiency of the Siemens SGT-100 gas turbine equipment was carried out. The expediency of applying the performed studies results of practical application in designing and operating gas turbine machines was substantiated.
General Approach to Calculation of Magnetic System of Slow-Moving Linear Magneto-Electric Drive as Part of Electrical Complex
Authors: Tatevosyan A A , Bubnov A V , Andreeva E G , Tatevosyan A S
Published: May 2020

Article discusses approach to development of linear magneto-electric drive using slow-moving electromechanical converter with permanent magnets Design of electrical complex uses solution of problem of optimization of linear magneto-electric motor design according to criterion of maximum developed traction force. The law of force change is implemented sinusoidal with constant component, frequency of oscillations up to 10 Hz. The weight and size and electromagnetic parameters of the linear magneto-electric drive are refined using the finite element method. The article presents the results of calculation of the main geometric parameters of the magnetic system.
Technique and device for filter elements regeneration based on powder filter material
Authors: Ilyushchanka A , Charniak I , Kusin A , Kusin R , Zakreuski I , Eremin E N
Published: May 2020

The design of a device for filter elements regeneration is presented without disassembling the filters in which they are installed. A distinctive feature of the device is the use of a preliminarily vacuumed chamber designed to discharge contaminants from the surface of the filter element. This makes it possible to increase the operation time of the filters before they are disassembled in order to clean the filters on special stands or replace them. The efficiency of the device in production conditions is shown by the example of cleaning an aqueous solution of peat hydrohumate by powder filter elements.
The matching of images based on de Rham current formation
Authors: Chukanov S N
Published: May 2020

The application of the de Rham current theory for matching forms of images is considered. The determination the measure of differences between simplicial complexes of forms does not imply a point bijective correspondence between the structures of objects. The RKHS method for obtaining object shape metrics is proposed. The study of the forms of objects is proposed to be carried out by forming test vector fields. Simplicial complexes of objects can be supplemented by the functions of the elements representing the signals. To improve the accuracy of matching the forms of the source and terminal images, the original image is subjected to preliminary affine transformation. The minimization of the functional of the squared distance between the image forms is carried out on the basis of the QPSO algorithm.
Mathematical modeling and numerical algorithm for the gas displacement by water in an inhomogeneous porous medium
Authors: Kholmatova I I
Published: May 2020

The problems associated with the development of gas fields bounded by aquifer systems are considered in the paper in order to increase gas recovery and determine the key parameters of the reservoir for further development. To conduct a comprehensive study of the process under consideration, a computer model has been developed that is described by a differential equation with variable coefficients under corresponding initial and boundary conditions and moving boundaries. An arbitrarily defined region is converted to a standard one using the dummy region method. Functional dependences of the parameters of porosity and permeability are constructed by the method of local approximation given at some defined points in the reservoir for each nodal point. An algorithm is developed for solving the problem using the methods of longitudinal-transverse scheme and the flow option of the sweep method. The results are shown as isolines. In this paper, an attempt is made to prove that in the practice of fluid production it is advisable to introduce development technology based on inhomogeneous formation parameters. Numerical experiments have shown that using this technology wide opportunities appear for finding highly effective design solutions for fields development.
Development of a cluster analysis method for solving the problem of identifying static voltage load characteristics
Authors: Kondrashov Mikhail A , Popov Maksim G , Bukharov Dmitry S , Petrushin Denis E
Published: May 2020

Identification of static voltage load characteristics is not a trivial task. It is extremely difficult to develop a single methodology that will allow achieving the required accuracy results for any input data. The authors made an attempt to solve the problem, developed a method based on the use of methods for processing large data sets – BigData. One of the most important stages of this method is the stage of cluster analysis. The problem of choosing a method of cluster analysis also has nuances: it is necessary to maintain a balance between time and accuracy of calculations, while performing calculations with sufficient accuracy on various data. A number of domestic and foreign authors have investigated this issue, but the proposed options cannot be used in the developed methodology. The purpose of this research is to develop a cluster analysis method that will satisfy the above requirements. The author’s method is based on the k-means method. The main feature of the author’s method is the mechanism of initial generation of cluster centroids, which allows to exclude the influence of random generation of two-dimensional coordinates imperfection and to achieve uniform generation of initial clusters centers. The developed method was tested on a model problem with all known solutions, which can be easily verified analytically. Also the method was tested on actual industrial load data. The results obtained the requirements of accuracy and calculation speed and allow us to conclude that the developed method of cluster analysis can be used in the task of identifying static voltage load characteristics.
Mathematical model and computational experiments for the calculation of three-layer plates of complex configuration
Authors: Nuraliev F , Anarova Sh , Amanov O , Jumaev S , Abdirozikov O
Published: May 2020

Mathematical model and computational experiments to solve the problems of bending of three-layer plates of complex configuration are considered in the paper. Mathematical model and computational algorithm given in the paper are developed on the basis of the Hamilton-Ostrogradky’s variation principle, the Bubnov-Galerkin methods and the Rvachev R-functions. Numerical results of the problem are presented. Results are given in tabular and graphical form. Numerical studies of the results obtained are analyzed using the R-function method in combination with the Bubnov-Galerkin variational method to solve the problem of calculating the vibration of three-layer plates of complex configuration.
Research of one interpolation formula at creation of the finite-difference scheme for functions with internal zones of the bigger gradients
Authors: Panichkin A V
Published: May 2020

In work the method creation of the interpolation formula which is bringing closer function of the smoothing gap, meeting in solutions of one-dimensional tasks with a heatmass transfer is investigated. Interpolation on the basis of the decision for the smoothing gap is used for creation of finite-difference schemes to multidimensional tasks with ruptures of the first sort in boundary and initial and regional conditions. Use of additional knots with the constructed interpolation gives considerable reduction of approximating viscosity in finite-difference schemes for the convective and diffusive equations of transfer. For the constructed interpolation in case of existence of an internal interface which thickness less step of a regular grid is conducted an accuracy research at the asymptotic approximations in small parameters corresponding to changes of required function in the neighborhood of a thin interface.

The carried-out numerical calculations on a heat and mass transfer for a test task in two-dimensional rectangular area on the basis of the developed method show increase in an asymptotic order of accuracy of numerical decisions to the second from a grid step at application of the known schemes in the wide range of small parameter of diffusion.
Multi-Class Text Classification of Uzbek News Articles using Machine Learning
Authors: Rabbimov I M , Kobilov S S
Published: May 2020

A large amount of online news on various topics is being posted on the Internet. One of the tasks of processing this data is to provide the user with appropriate methods and tools for quick and easy search for important and interesting news. An approach to solve this problem is the reasonable distribution of news into respective classes. This increases the importance of automated classification of an electronic document section. In this paper, we consider the task of multi-class text classification for the texts written in Uzbek. The articles on ten categories were selected from the Uzbek “Daryo” online news edition and a dataset was developed for them. When performing multi-class text classification for this dataset, the following 6 different machine learning algorithms were used: Support Vector Machines (SVM), Decision Tree Classifier (DTC), Random Forest (RF), Logistic Regression (LR) and Multinomial Naïve Bayes (MNB). A detailed technological description of the stages of the proposed functional scheme of text classification and developed software is given. The TF-IDF algorithm and word-level and character-level n-gram models were used as the feature extraction methods. When defining hyperparameters for text classification, 5-fold cross-validation was used. Experiments were conducted and the highest accuracy was 86.88%. The models and methods that are proposed in this paper can be successfully used in the classification of texts written in the Uzbek language and further research in this area.
A generic algorithm for the word problem in semigroups and groups
Authors: Rybalov Alexander
Published: May 2020

Kapovich, Myasnikov, Schupp and Shpilrain in 2003 developed generic approach to algorithmic problems, which considers an algorithmic problem on “most” of the inputs instead of the entire domain and ignores it on the rest of inputs. Myasnikov, Ushakov and Won in 2008 constructed a simple generic algorithm for the word problem in some finitely defined semigroups, including classical semigroups with undecidable word problem: Tseitin semigroup, Makanin semigroup and Matiyasevich semigroup. But this algorithm does not work for wider classes of semigroups: for example, semigroups with one relation. In this paper we present new generic algorithm for a wide class of finitely defined semigroups, including Tseitin and Makanin semigroups, semigroups with one relation. This algorithm can be viewed as advanced development of the Myasnikov-Ushakov-Won algorithm. Also we adopt our generic algorithm for the word problem in some finitely defined groups, including classical examples of groups with undecidable word problem. The work is supported by Mathematical Center in Akademgorodok, the agreement with Ministry of Science and High Education of the Russian Federation number 075-15-2019-1613.
Numerical differentiation on the Bakhvalov mesh in the presence of an exponential boundary layer
Authors: Zadorin N A
Published: May 2020

The question of the application of formulas of the numerical differentiation of functions in the presence of the exponential boundary layer is investigated. The problem is that the application of classical formulas, wich are based on the differentiation of the Lagrange polynomial on the uniform mesh in this case leads to significant errors. It is proposed to study the formulas for derivatives on the Bakhvalov mesh, which is widely used in the construction of difference schemes for singularly perturbed problems. It is proved that applying of classical difference formulas for derivatives on a Bakhvalov mesh have error estimate that is uniform with respect to a small parameter. The results of numerical experiments are presented.
Computer simulating of nanoprocesses: Thermal jumps over a low barrier in the overdamped regime
Authors: Chushnyakova M V , Gontchar I I , Kuzyakin R A
Published: May 2020

We model numerically the process of a thermally activated decay of a metastable state over a low barrier in the overdamped regime. This process is typical for the recent nanoscale experiments reported in the literature. Within the framework of a novel unified computer code, two ways of modeling are applied: (i) the partial differential equation (Smoluchowski equation) and (ii) the stochastic ordinary differential equation (Langevin equation for the generalized coordinate). The advantages and disadvantages of both approaches are discussed and analyzed. Special attention is paid to the transient stage of the process yet the quasistationary stage is considered as well.
Investigation of interactions in the cenospheres-electrolyte system
Authors: Fedyaeva O A , Poshelyuzhnaya E G
Published: May 2020

The chemical composition of cenospheres have been studied by the methods of physical and chemical analysis. The products of their interaction with water and solutions of hydrochloric acid, sodium hydroxide and sodium chloride have been determined. It has been established that cenospheres dissolve in aqueous solutions regardless of pH. Pre-treatment of cenospheres in water and solutions of hydrochloric acid and sodium hydroxide reduces their dissolution in sodium chloride solution. Calcium ions, bicarbonate ions, silanol and aluminol groups of the surface participate in the ion exchange.
Influence of elastic characteristics of a track roller rim of a caterpillar system on the stress-strain state of an external rubber tire
Authors: Korostelev S A , Medvedev Yu V , Verbilov A F
Published: May 2020

The stress-strain state of the rubber tire of the track roller of the caterpillar mover is determined when considering the problem with an absolutely rigid rim and with an elastic rim. The effect of the rim elasticity on the radial stiffness of the track roller, on the distribution of contact pressure, and also on the distribution of the specific strain energy, which is a criterion for the fatigue strength of rubber, is shown. Two cases of the interaction of the track roller with the track are considered. The first case corresponds to the location of the axis of the track roller parallel to the chain link, the second case, when the plane of the track is located at an angle relative to the axis of the track roller. The influence of the angle of inclination of the support surface on the stress-strain state of the external rubber tire of the support roller is shown. The mechanical properties of a rubber tire are described by the elastic Treloar potential, the rim material of the track roller is considered linear elastic material.
Longitudinal waves in a cylinder with active external friction in a limited area
Authors: Sultanov Karim S , Khusanov Bakhtiyar E , Rikhsieva Barno B
Published: May 2020

The problem of longitudinal wave propagation in a cylindrical body in the presence of an incompressible external medium in a length limited area is solved in the paper in a one-dimensional statement. Along with the non-uniformity of motion, the friction force arising on the contact surface directly depends on the parameters of propagating waves. Numerical results are obtained using the finite-difference method according to the Wilkins scheme for axisymmetric problems. The results of wave propagation in a cylindrical body with a rigid external medium frame limited in length are presented. According to the calculation results, an increase in wave parameters (stresses and particle velocity) over time and with distance are observed as well as the causes of stress increase mechanism in the cylinder; the effect of external load parameters and physical-mechanical characteristics of the cylinder on the parameters of propagating waves are determined. Waves arising from active friction and reflected from the boundaries are revealed and the effect of location and length of external medium on changes in wave parameters in the cylinder is revealed.
Plasmonic Nanobiosensing: from in situ plant monitoring to cancer diagnostics at the point of care
Authors: Crawford Bridget M , Wang Hsin-Neng , Strobbia Pietro , Zentella Rodolfo , Pei Zhen-Ming , Sun Tai-ping , Vo-Dinh Tuan
Published: May 2020

Nucleic acid biosensing technologies have the capability to provide valuable information in applications ranging from medical diagnostics to environmental sensing. The unique properties of plasmonic metallic nanoparticles have been used for sensing purposes and among them, plasmonic sensors based on surface-enhanced Raman scattering (SERS) offer the advantages of sensitive and muliplexed detection owing to the narrow bandwidth of their characteristic Raman spectral features. This paper describes current applications that employ the unique SERS-based inverse molecular sentinel (iMS) nanobiosensors developed in our laboratory. Herein, we demonstrate the use of label-free iMS nanoprobes for detecting specific nucleic acid biomarkers in a wide variety of applications from cancer diagnostics to genetic monitoring for plant biology in renewable biofuel research.
An ultraweak-local discontinuous Galerkin method for PDEs with high order spatial derivatives
Authors: Tao Qi , Xu Yan , Shu Chi-Wang
Published: May 2020

In this paper, we develop a new discontinuous Galerkin method for solving several types of partial differential equations (PDEs) with high order spatial derivatives. We combine the advantages of a local discontinuous Galerkin (LDG) method and the ultraweak discontinuous Galerkin (UWDG) method. First, we rewrite the PDEs with high order spatial derivatives into a lower order system, then apply the UWDG method to the system. We first consider the fourth order and fifth order nonlinear PDEs in one space dimension, and then extend our method to general high order problems and two space dimensions. The main advantage of our method over the LDG method is that we have introduced fewer auxiliary variables, thereby reducing memory and computational costs. The main advantage of our method over the UWDG method is that no internal penalty terms are necessary in order to ensure stability for both even and odd order PDEs. We prove the stability of our method in the general nonlinear case and provide optimal error estimates for linear PDEs for the solution itself as well as for the auxiliary variables approximating its derivatives. A key ingredient in the proof of the error estimates is the construction of the relationship between the derivative and the element interface jump of the numerical solution and the auxiliary variable solution of the solution derivative. With this relationship, we can then use the discrete Sobolev and Poincaré inequalities to obtain the optimal error estimates. The theoretical findings are confirmed by numerical experiments.
Structure of multicorrelation sequences with integer part polynomial iterates along primes
Authors: Koutsogiannis Andreas , Le Anh , Moreira Joel , Richter Florian
Published: May 2020

Let

T
T

be a measure-preserving

Z

ℓ

\mathbb {Z}^\ell

-action on the probability space

(
X
,

B

,
μ
)
,

(X,{\mathcal B},\mu ),

let

q
1

,
…
,

q
m

:

R

→

R

ℓ

q_1,\dots ,q_m\colon \mathbb {R}\to \mathbb {R}^\ell

be vector polynomials, and let

f
0

,
…
,

f
m

∈

L
∞

(
X
)

f_0,\dots ,f_m \in L^\infty (X)

. For any

ϵ
>
0

\epsilon > 0

and multicorrelation sequences of the form
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="alpha left-parenthesis n right-parenthesis equals integral Underscript upper X Endscripts f 0 dot upper T Superscript left floor q 1 left-parenthesis n right-parenthesis right floor Baseline f 1 midline-horizontal-ellipsis upper T Superscript left floor q Super Subscript m Superscript left-parenthesis n right-parenthesis right floor Baseline f Subscript m Baseline d mu">

α
(
n
)
=

∫
X

f
0

⋅

T

⌊

q
1

(
n
)
⌋

f
1

⋯

T

⌊

q
m

(
n
)
⌋

f
m

d
μ

\alpha (n) =\int _Xf_0\cdot T^{ \lfloor q_1(n) \rfloor }f_1\cdots T^{ \lfloor q_m(n) \rfloor }f_m\;d\mu

we show that there exists a nil- sequence

ψ
\psi

for which
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="limit Underscript upper N minus upper M right-arrow normal infinity Endscripts StartFraction 1 Over upper N minus upper M EndFraction sigma-summation Underscript n equals upper M Overscript upper N minus 1 Endscripts StartAbsoluteValue alpha left-parenthesis n right-parenthesis minus psi left-parenthesis n right-parenthesis EndAbsoluteValue less-than-or-equal-to epsilon">

lim

N
−
M
→
∞

1

N
−
M

∑

n
=
M

N
−
1

|

α
(
n
)
−
ψ
(
n
)

|

≤
ϵ

\lim _{N - M \to \infty } \frac {1}{N-M} \sum _{n=M}^{N-1} |\alpha (n) - \psi (n)| \leq \epsilon

and
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="limit Underscript upper N right-arrow normal infinity Endscripts StartFraction 1 Over pi left-parenthesis upper N right-parenthesis EndFraction sigma-summation Underscript p element-of double-struck upper P intersection left-bracket 1 comma upper N right-bracket Endscripts StartAbsoluteValue alpha left-parenthesis p right-parenthesis minus psi left-parenthesis p right-parenthesis EndAbsoluteValue less-than-or-equal-to epsilon period">

lim

N
→
∞

1

π
(
N
)

∑

p
∈

P

∩
[
1
,
N
]

|

α
(
p
)
−
ψ
(
p
)

|

≤
ϵ
.

\lim _{N \to \infty } \frac {1}{\pi (N)} \sum _{p \in \mathbb {P}\cap [1,N]} |\alpha (p) - \psi (p)| \leq \epsilon .

This result simultaneously generalizes previous results of Frantzikinakis and the authors.
Entrance laws at the origin of self-similar Markov processes in high dimensions
Authors: Kyprianou Andreas , Rivero Victor , Şengül Batı , Yang Ting
Published: May 2020

In this paper we consider the problem of finding entrance laws at the origin for self-similar Markov processes in

R

d

\mathbb {R}^d

, killed upon hitting the origin. Under suitable assumptions, we show the existence of an entrance law and the convergence to this law when the process is started close to the origin. We obtain an explicit description of the process started from the origin as the time reversal of the original self-similar Markov process conditioned to hit the origin.
Characteristic class and the 𝜖-factor of an étale sheaf
Authors: Umezaki Naoya , Yang Enlin , Zhao Yigeng
Published: May 2020

We prove a twist formula for the

ε
\varepsilon

-factor of a constructible sheaf on a projective smooth variety over a finite field in terms of characteristic class of the sheaf. This formula is a modified version of the formula conjectured by Kato and Saito in [Ann. of Math. 168 (2008), pp. 33–96].

We give two applications of the twist formula. First, we prove that the characteristic classes of constructible étale sheaves on projective smooth varieties over a finite field are compatible with proper push-forward. Secondly, we show that the two Swan classes in the literature are the same on proper smooth surfaces over a finite field.
Anointments and Prestige: Reflecting on #CommunicationSoWhite with Herman Gray and Oscar Gandy
Authors: Costley White Khadijah
Published: May 2020

Oscar Gandy, Jr. is a Professor Emeritus at the Annenberg School for Communication and a political economist. He is the author of four books, including Communication and Race: A Structural Perspective (1998), as well as numerous publications. Herman Gray is Professor Emeritus of sociology at UC Santa Cruz. He is the author of the books Watching Race and Cultural Moves, and many other scholarly writings. I spoke with both of them together about #CommunicationSoWhite, asking them as senior black scholars to reflect on contemporary discussions and suggest ways forward in the field of communication and media studies. 1 The interview is edited for brevity and clarity.
Neuronal Correlates of Many-To-One Sensorimotor Mapping in Lateral Intraparietal Cortex
Authors: Zhou Yang , Liu Yining , Zhang Mingsha
Published: May 2020

Efficiently mapping sensory stimuli onto motor programs is crucial for rapidly choosing appropriate behavioral responses. While neuronal mechanisms underlying simple, one-to-one sensorimotor mapping have been extensively studied, how the brain achieves complex, many-to-one sensorimotor mapping remains unclear. Here, we recorded single neuron activity from the lateral intraparietal (LIP) cortex of monkeys trained to map multiple spatial positions of visual cue onto two opposite saccades. We found that LIP neurons’ activity was consistent with directly mapping multiple cue positions to the associated saccadic direction (SDir) regardless of whether the visual cue appeared in or outside neurons’ receptive fields. Unlike the explicit encoding of the visual categories, such cue–target mapping (CTM)–related activity covaried with the associated SDirs. Furthermore, the CTM was preferentially mediated by visual neurons identified by memory-guided saccade. These results indicate that LIP plays a crucial role in the early stage of many-to-one sensorimotor transformation.
Adverse Outcomes in Pregnant Women Hospitalized With Respiratory Syncytial Virus Infection: A Case Series
Authors: Hause Anne M , Panagiotakopoulos Lakshmi , Weintraub Eric S , Sy Lina S , Glenn Sungching C , Tseng Hung-Fu , McNeil Michael M
Published: May 2020

We identified 10 women hospitalized with respiratory syncytial virus infection during pregnancy. Diagnoses included pneumonia/atelectasis (5), respiratory failure (2), and sepsis (2). Six had obstetrical complications during hospitalization, including 1 induced preterm birth. One required intensive care unit admission and mechanical ventilation. Four infants had complications at birth.