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  • Reviews, suggestions and discussions

  • Life cycle analysis of engineering education systems in different countries

    Life cycle analysis of engineering education systems. Engineering education in the leading countries. Deep crisis of Ukrainian and Russian engineering education.сведения и выводы описываемой работы, и рассчитана на самый широкий круг читателей.

    Keywords: education in different countries, life cycle analysis of education systems

  • The use of unmanned aerial vehicles in construction

    This paper discusses the use of unmanned construction vehicles in the construction industry. Statistics on the growth of investment in the production of construction drones are given. The main directions of using drones in the construction industry are described in detail: topographic survey, urban planning, improving safety on construction sites, roof inspection, building maintenance, security surveillance. The main advantages of new technologies in comparison with traditional ones are indicated and justified. Some shortcomings of modern unmanned technologies from the legal point of view are noted. In conclusion, the article draws conclusions about the future prospects for the use of unmanned aerial vehicles in construction, which will lead to an increase in labor productivity in the industry.

    Keywords: inspection of buildings and structures, quadrocopter, drone, unmanned aerial vehicle, UAV, construction, modern technologies, quadrocopter, security, innovation

  • Best practices in the construction of energy-efficient buildings of educational institutions

    The review and analysis of the European practices of construction of educational institutions is carried out. The main features of architecture and energy-efficient solutions in the projects of educational institutions in Europe are considered.

    Keywords: construction, school facility, world construction experience, architecture, landscaping, zoning, landscaping, landscape, energy efficiency, energy-efficient technologies

  • Physical and mathematical sciences. Physics

  • Frequency variability of the vertical profile of the first normal mode of pressure and particle velocity in a shallow water waveguide

    The article is devoted to the analysis of the vertical structure of the acoustic pressure field and the first-mode particle velocity in a hydroacoustic waveguide in shallow water. A waveguide consisting of a water layer with a constant sound velocity profile, a transition layer, and a half-space is considered. The acoustic properties of the transition layer are assumed to be frequency dependent. Formulas are derived that describe the vertical profile of the normal mode of a particle velocity. The transformation of the vertical profile of the first mode with increasing frequency is analyzed. The phase difference relations between the normal mode of acoustic pressure and particle velocity are analyzed. A relationship is established between the change in the vertical structure of the normal modes of pressure and particle velocity and the acoustic properties of the transition layer.

    Keywords: normal modes, particle velocity, seabed, attenuation coefficient

  • Ion strontium vapor laser in a regime of multiwave laser oscillation

    Numerical investigations of the dependences of the output characteristics of the ion strontium vapor laser on the pressure and temperature of the active medium were carried out. Based on the results of calculations, a range of conditions for the excitation of the active medium was found for the realization of the multiwave lasing regime on visible and infrared transitions of the strontium ion (λ=430.5; 416.2; 1091 and 1033 nm SrII). A number of patterns were revealed that are inherent in the active medium of a strontium vapor laser, and the physical mechanisms that determine them were established. The investigations results provide a possibility to choose the conditions for optimal excitation of multiwave strontium vapor lasers, as well as to control the relative contribution of various spectral components to the output radiation.

    Keywords: multiwave radiation, recombination pumping, self-termination transition, strontium vapor laser, numerical modeling

  • Study of Homogeneous Catalytic Oxidation of Hydrogen Sulfide by Air Oxygen in a Reactor with a Membrane Separator

    The results of studies of the kinetics of the iron-catalytic oxidation of hydrogen sulfide by atmospheric oxygen in a reactor with a membrane separator are presented. The studies were carried out on a laboratory experimental complex. The dependences were obtained experimentally showing the effect of the catalyst dose - Fe (OH) 3¬, the pH of the medium, and the contact time of the water being purified with the reaction medium on the effect of water purification from hydrogen sulfide.

    Keywords: hydrogen sulfide, iron catalytic oxidation, air oxygen, iron hydroxide, membrane separation, ultrafiltration

  • Identification and assessment of the factors of the working environment during the operation of hoisting machines

    This article presents the results of identification and assessment of the factors of the working environment, as well as highlights the vibroacoustic factors that have the greatest impact on the working capacity and health of the operators of hoisting machines.

    Keywords: identification, hoisting machines, acoustic discomfort, noise and vibration spectra, working conditions

  • GaInAsBi epitaxial films based on indium arsenide - a new material for infrared lighting technology

    The results of a theoretical and experimental study of the synthesis of GaInAsBi thin-film structures formed on InAs substrates in the field of a temperature gradient are discussed. The features of interfacial interaction in the In-As-Sb system in the presence of isovalent solvents (In, Bi) have been studied. The values ​​of the interaction parameters and the distribution coefficients of the system components are determined. Optimal technological modes for obtaining InAs-based heterostructures are presented. The properties of the surface of epitaxial layers are studied experimentally. It was found that the main control parameters are the temperature of thermomigration and its gradient. It is shown that the synthesized semiconductor materials can be effectively used in electronic devices of a new generation - electro-optical modulators and supersensitive sensor elements.

    Keywords: epitaxial structure, crystallization, recrystallization, melt, segregation coefficient, organometallic compound, voltage sensitivity, near infrared range, solid solution, optical characteristic

  • Surface characteristics of cobalt catalysts on NaX zeolite

    The physicochemical properties of cobalt catalysts on a NaX zeolite support have been studied. The parameters of the specific surface area, reduction of deposited cobalt, and structural properties of the active component of catalytic systems have been determined. To establish these properties, the methods of BET, TPR, TPD-H2, IR spectroscopy were used. It is shown that the preparation procedure has a significant effect on the physicochemical characteristics of the samples.

    Keywords: catalysts, cobalt, zeolite, dispersion, specific surface area of the active component

  • Technical science. Informatics, computer facilities and management

  • Cluster analysis in solving tasks management of fire hazardous events in social and economic systems

    This work is devoted to the application of cluster analysis in solving tasks of managing fire hazardous events in socio-economic systems. The simulation results showed that, depending on the factors that determine the fire situation in the territory, it is possible to assess the fire hazard in the region. The proposed approach will allow planning the necessary fire-fighting measures as part of a unified state system for the prevention and elimination of emergencies at various levels.

    Keywords: objects, fire situation, territories, living sector, socio-economic system, cluster analysis

  • Predicting the state of a stochastic system on electrified railways

    Stochastic systems are systems in which changes are random. In which the predicted values depend on a probability distribution. An example of a stochastic system in a power system, the operation of which is affected by many random factors, their analysis and control will allow you to control the safe cycle and reliability of operation. Currently, there are methods and mathematical tools that allow us to estimate the likelihood of any phenomenon and situation with acceptable accuracy, however, they are practically not used to solve this problem on electrified railway transport. Therefore, the work summarizes the existing methods of probabilistic forecasting, and gives recommendations on their application to solve the existing problematic of the issue. Further, the paper shows a method for determining the probability of failure of a constituent structural element of any, arbitrarily complex, stochastic system, to which the contact network of electrified railways belongs. In the conclusion of the work, an elementary method-oriented software tool with the functional purpose of automating statistical methods for solving problems of primary data processing and calculating elementary statistics in the process of risk management is proposed, as well as loading and maintaining a database that is subsequently oriented to the principles of machine learning.

    Keywords: electrified railways, stochastic systems, operational reliability, probability of failure, forecasting

  • Development of an algorithm for identifying the parameters of object models using the example of a temperature control system

    The article discusses the main stages of identification of a control system for maintaining a given temperature, which includes an actuator, a control object and a temperature sensor. The initial data were experimental values ​​obtained under various setting influences on objects of the material world. To confirm the accuracy of the calculations and the selected methods for identifying parameters, mathematical modeling of the system in the Matlab / Simulink package is presented. At the end of the article, quantitative and qualitative assessments of the obtained mathematical models are given. The identification of the parameters of the control system for maintaining the set temperature was successful. The developed algorithm for describing material objects by mathematical models showed a low error, which indicates the applicability of this approach in real technological processes of production management.

    Keywords: identification, mathematical model, control object, control system, transient response, full-scale experiment, transfer function

  • Bionic prosthesis control system based on electromyography

    The work is devoted to some questions of prosthetics of human limbs. A prototype of a prosthesis control system based on electromyography is suggested, which is not inferior to existing analogues, but significantly benefits in its cost.

    Keywords: bionic prosthesis, electromyography, EMG sensor, amplifier

  • Classification of the states of urban infrastructure objects using neural networks

    The possibility of using neural networks to classify the states of complex objects is considered. A software implementation of a neural network classifier is made and the results are compared with a selection algorithm based on K-nearest neighbors.

    Keywords: classification, neural networks, decision making, case

  • Heavy metals migration modelling in soil by the ground source near the Novocherkasskiy hydroelectric power plant

    The modeling heavy metal transfer by the ground source to the lower boundaries of the soil is considered. The transfer process is described by a system of equations included the Navier-Stokes equation, the k-ε model and the nonstationary diffusion equation. The initial and boundary conditions are given at the boundaries of the air and liquid in the soil flow, also in the air-ground contact zone, which are necessary for solving the boundary value problem. The results of numerical simulation obtained using the ANSYS fluent program are shown. The result analysis is based on the comparison of numerical modelling and long-term observations data around the hydroelectric power plant.

    Keywords: k-ε model, diffusion equation, numerical modelling, ANSYS, Novocherkasskiy hydroelectric power plant

  • Development of an AC voltage regulator

    An urgent scientific and technical task is the development of electric energy converters with high operational and energy characteristics. The use of modern methods for the development and analysis of power electronics circuits based on the use of computer equipment allows us to successfully solve this problem. In this article, a schematic diagram of an alternating voltage regulator has been developed, in which a control system based on a microcontroller implementing an algorithm for pulse-phase regulation of the variable output voltage is used to control a power thyristor key. The control system, a power thyristor key, is synchronized with the moments of transition through zero of the supply voltage of a sinusoidal shape. The controller circuit is adapted for computer modeling in the environment of the PROTEUS software product. In the article, a block diagram is also developed and a software implementation in assembly language of the microcontroller operation algorithm is performed. As a result of computer modeling, time diagrams of voltages on the main elements of the AC voltage regulator circuit are obtained. Time diagrams explain the features of electromagnetic processes occurring in the controller circuit. The results of computer modeling, the controller circuit, the developed algorithm and the microcontroller software can be used in the development of electric energy converters for automatic control systems of electrical equipment.

    Keywords: computer simulation, thyristor regulator, alternating voltage, microcontroller operation algorithm, time diagrams, transistor switch, control system, damping circuit, power thyristor, active-inductive load

  • Conceptual model of management of indicators of scientific activity of universities

    The article proposes a structural and functional model of the performance management system of Russian universities based on rating ratings. The system consists of four main integrated components related to each other: the Ministry of Science and Higher Education of the Russian Federation, national and international rating agencies, Russian universities and the unit for evaluating integral indicators of universities by type of activity. The particular indicators of the activity of universities that most affect the values of integral ones are determined. The key factors influencing particular indicators are identified. Such a structural and functional representation of the performance management system of universities allows us to apply statistical and simulation modeling methods for its analysis. The use of the proposed model will make it possible to predict the values of private indicators of the activity of universities, depending on the key factors of influence. This will allow the management of universities to make scientifically-based management decisions to improve the efficiency of the functioning of universities.

    Keywords: performance indicators, scientific activity, publication activity, modeling, Scopus, Web of Science

  • Investigation of the heat transfer process in a cylindrical fuel element

    the presented work is devoted to the study of the temperature state of a fuel element (fuel element) – a cylindrical solid body with an internal heat source of constant power. Using the integral method of heat balance with the introduction of an additional desired function, an approximate analytical solution of the corresponding boundary value problem of thermal conductivity is obtained. The conditions of external heat transfer at the boundary of the studied region were set according to the Newton-Richman law (a boundary condition of the third kind). When obtaining the solution, trigonometric coordinate functions were used. Their use made it possible to reduce the number of terms in the desired solution due to the a priori fulfillment of the boundary condition in the center of the fuel element. It is shown that when using only three terms in the analytical solution (the first approximation), an accuracy sufficient for engineering applications is achieved. The error of the developed method was estimated by comparing the results obtained with a numerical solution based on the finite difference method. The article presents graphs of the temperature distribution at different power values of volumetric fuel element heat sources. The developed method can be used to determine the time of the system's exit to the stationary mode, estimate the maximum fuel element temperature at various values of the dimensionless Bio and Pomerantsev numbers, and determine temperature stresses.

    Keywords: internal heat sources, boundary conditions of the third kind, additional desired function, heat balance integral, heat-generating element, approximate analytical solution, numerical solution, heat conduction problem, Bio number, Pomerantsev number

  • Traffic control system using a fuzzy regulator at an intersection

    The growth in the number of vehicles on the streets of cities leads to adverse consequences: an increase in congestion, the occurrence of road accidents. In order to take measures for the efficient use of road transport roads in order to avoid unfavorable congestion situations, it is proposed to control traffic flows using a fuzzy regulator along the length of the queue in each of the conflicting directions. The optimization principle is based on minimizing the length of the queue of traffic flows, which allows the most efficient use of the transport bed, avoiding unwanted congestion situations. On the developed model of the intersection, a system with fuzzy regulation of traffic signals is proposed. The average idle time is estimated with a fixed traffic light cycle and with a fuzzy control. With the use of a fuzzy regulator, the average queue at the intersection decreased by 11%.

    Keywords: fuzzy regulator, traffic flow, intersection, traffic control system, control algorithm, vehicle intensity

  • Predictive analysis of the state of objects as a new strategy for the technical operation of electrified railways

    Stable reliability characteristics are a guarantee of non-emergency operation of electrified railways, undoubtedly, the profitability of transportation processes is growing. The article proposes an innovative method for determining the characteristics of reliability, with a decrease in the risk of failure or emergency. Electric traction used in most of the railroad landfill. It is necessary to consider the issues of reliability of the power supply system to predict the state of the system and study the patterns of interaction that affect system and non-system communications. Therefore, we will pay special attention to the reliability of the power supply system; in order to predict failures, first of all, it is necessary to know the patterns of interaction and patterns that affect system and non-system communications. The danger of risk directly depends on the number and duration of failures. In the power supply system, a huge number of heterogeneous and differently distributed objects, nodes and elements operate in different modes and are susceptible to different operational influences.Therefore, the work summarizes the existing methods of probabilistic forecasting, and gives recommendations on their application to solve the existing problematic of the issue. Further, the paper shows a method for determining the probability of failure of a constituent structural element of any, arbitrarily complex, stochastic system, to which the contact network of electrified railways belongs. In the conclusion of the work, an elementary method-oriented software tool with the functional purpose of automating statistical methods for solving problems of primary data processing and calculating elementary statistics in the process of risk management is proposed, as well as loading and maintaining a database that is subsequently oriented to the principles of machine learning.

    Keywords: electrified railways, predictive analysis, operational reliability, probability of failure, forecasting

  • Mathematical models of the measurement error of the main magnetization curve of electrical steel sheet

    The paper considers mathematical models obtained on the basis of experimental studies of electrical sheet steel. The models reflect the error in determining the main magnetization curve of electrical steel. The magnetic properties are determined in the center and at the edge of the cut of sheet samples with a size of 150 × 150 mm, made by cutting with guillotine shears and laser cutting. The choice of scale factors for calculating the main magnetization curve with an error of ± 5% according to the measured Weber-ampere characteristic has been substantiated. The study was carried out using a device for express control of the magnetic characteristics of electrical sheet steel. The main curve of magnetization of the sample material from sheet electrical steel was determined in an alternating magnetic field with a frequency of 50 Hz, along the direction of rolling. Investigated samples of isotropic sheet electrical steel grade 2212.

    Keywords: mathematical model, electrical steel, magnetic properties, magnetization curve

  • Reducing feature space in human hand movement models

    The article presents results of processing motion data obtained on a motion capture system using inertial microelectromechanical sensors (MEMS). Hardware and software complex compares reference movements with those that operator is performing. Reducing the feature space in motion model is an important task in the context of using many similar sensors that need to be processed on low-power devices. The main way to obtain the distance between two patterns is algorithm of dynamic time warping which has a computational complexity of O2, which means that it is expedient to select features. Statistics of distinction degree between different types of movements are provided to assess the quality of simplified models. Сomplexity of resulting models was demonstrate on Kohanovsky method.

    Keywords: MEMS, motion capture, correlation analysis, wavelet transform, dynamic time-warping algorithm, accelerometer, gyroscope, inertial sensor, motion control, pattern matching