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  • Prototype of a multichannel digital ammeter

    In this article, a prototype of a multichannel digital ammeter will be considered. The structural scheme and algorithm of the program for the microcontroller is presented.

    Keywords: ammeter, digital ammeter, multichannel digital ammeter, prototype ammeter, Hall sensor, Hall effect

  • Features of structural evaluation of protective pressure-tight shell of nuclear power plants with a VVER-1000 reactor during the construction period

    The issues of evaluation features of reinforced concrete structures of protective shells of the NP-1000 project of nuclear power plants with a the water-water energetic reacto (VVER-1000) during the construction period are considered. The results of measurements of the strength characteristics of concrete, the thickness of the protective layer of reinforcement and the parameters of cracks made in the framework of the instrumental survey are given. The conducted instrumental survey allowed us to obtain fairly complete and reliable information about the parameters of the elements of the protective pressure-tight shell to perform calculations of the stress-strain state of the shell.

    Keywords: protective pressure-tight shell, methods of non-destructive testing, deformations, displacements, cracks, strength of concrete

  • Simple led illuminator for fluorescent research of biological objects

    The manuscript describes the design of a simple LED illuminator for fluorescence microscopy of biological objects. As the light source, high-brightness semiconductor diodes were chosen that provide stable low-noise light. This distinguishes them from traditional light sources, such as mercury lamps. The presented light source can be used to record low-amplitude fluorescent signals in studies of excitable cells performed using calcium or potential-sensitive dyes. The illuminator is made of inexpensive, easily accessible components.

    Keywords: high-brightness LEDs, illuminator, fluorescence, microscopy

  • The principle of covering the costs of a construction company

    The issue of improving the cost coverage of the construction company is considered. The authors consider the issues of break-even production. The article deals with three main sources of losses of a construction company. Measures to eliminate them are proposed

    Keywords: organization of construction; economy of construction, break-even production

  • The motion control algorithm of a group of mobile robots in conditions of uncertainty

    The article proposes an algorithm for the functioning of adaptive motion control systems of a group of mobile transport robots in conditions of uncertainty. The algorithm was developed based on the Markov method of identification and the method of analytical synthesis of systems with control by output and effects. The adaptive control system in which this algorithm is used has direct quality indicators not worse than those specified. The proposed algorithm can be used to create control systems for technical objects of various types, with previously unknown mathematical models.

    Keywords: mobile robot, group, uncertainty, identification, Markov parameter, control by output and effects, system

  • Digital gas sensor for portable and wireless gas analyzers

    The article describes the concept of the digital gas sensors for toxic and flammable gases used in portable gas analyzers and stationary systems for dangerous objects monitoring. The results of the development of the low-power digital gas sensor for determining the concentration of carbon monoxide are described. The structure of the analog sensitive element, as well as its sensitivity to various gases and ambient temperature, is considered. A structural and schematic solution of a digital gas sensor using operational amplifiers and a miniature microcontroller is presented. The algorithm of firmware of the microcontroller is considered, as well as the calibration process.

    Keywords: Digital gas sensor, toxic gas, gas converter, carbon monoxide, gas analyzer, monitoring system, calibration process, gas generator

  • The reconstruction of the architectural ensemble of the mosque of Sultan-Saodat

    The problem of reconstruction of architectural structures of Central Asia is studied. The stages and periodization of the ensemble construction are considered. The basic design solutions of buildings are determined

    Keywords: organization of construction; economy of construction, history of the construction industry

  • Lateral-torsional buckling of a beam

    Beams are structural elements subjected to bending loads transverse to their longitudinal axis. For steel beams, which compressed flange is not laterally restrained, checking loss of overall stability is often authoritative in determining their section. In engineering practice are known various approaches to verify the assurance of the steel beam against lateral-torsional buckling. In this article the attention is focused to the methods and their characteristics, described in actual version of the European standard EN1993-1-1.

    Keywords: lateral-torsional buckling, steel beams, critical bending force, FEA

  • The Analyisis of the Situations in geopolitically unstable Zones as a specific scientific Procedure: the Scheme of the Second Stage

    This work represents the third article within the cycle devoted to the peculiarities of the analysis of the situations in geopolitically unstable zones of the modern world. This time the author focuses on the second stage of the mentioned scientific procedure. He assumes the analysis of the dynamics of such zones (regions) as multifactorial combinatorics, with the dominance of the conflict nature of interstate relations and the key role (in some cases) of non-regional players. An attempt is made to present unstable regions and the same kind of limitrophic zones as a combination and overlapping of the force fields of a different nature.

    Keywords: modern world, geopolitically unstable zones, separation belts, limitrophic zones, interstate relations, multilateral and vertically organized, conflictness, asymmetrical conflits, international mediation, force fields

  • On the assessment of the particles’ shape factor using results a complex analysis of variance of dispersed dust particles to reduce dust leakage throw out emissions in the dust removal devices of the aspiration schemes at the building construction industr

    The article is devoted to the approach to the development and design of effective dust collectors for the aspiration systems of the construction industry. It was proposed and implemented the study of the particle shape factors that determine the hydrodynamic features of gas flow around dust particles, for example, in the aspiration schemes, which are most spread and applied in the construction industry using the results of complex analysis of variance it this article. It was presented results of implementation hydrodynamic criteria in the output function of the analysis. The values’ meanings of the particle shape factors of the dusts’ particles were gained and obtained at the final stage of experiment. It was obtained regressions for particle shape factors as functions of hydrodynamic criteria. It was proposed dependences to clarify the particle sedimentation-growth velocities taking into account the influence of the particle shape factors of the studied dust samples. It was allowed possibility to assess and obtain ranges of changes in the values’ meanings of particle shape factors. It was obtained more reliable results for determining the sedimentation values’ velocities of dust particle as a determining result of complex analysis of variance of particles also. The research results allow the development and design of dust collecting devices for cleaning emissions in dust removal systems of the aspiration schemes of the construction industry. These dust kinds of collector provides a significant reduction in dust leakage out from dust removal systems of the aspiration. This way become one of the highly effective prevents polluting ways that allows to improve environmental safety of the construction industry.

    Keywords: Dust, building material, dust collector, cleaning, leakage, analysis of variance, velocity, sedimentation, criterion, emission, atmosphere, dust removal, aspiration

  • Studies of dustiness in a residential area located near industrial enterprises with PM10 and PM2.5 particles

    When organizing work on the territory of sanitary protection zones, it is necessary to take into account that the SPZ is already a territory with elevated levels of exposure, which may require the use of additional means of individual and collective protection. Meteorological parameters are important factors affecting the extent of the impact of the work on human health. The article presents a comparative analysis of the concentration of suspended substances in the workplace, depending on meteorological parameters.

    Keywords: sanitary protection zone, hazard class, industrial enterprise, construction, reconstruction, ecology, atmosphere, labor protection, non-stationary workplace

  • Numerical study of the heat sink with a change in the aggregate state of the working substance

    In the article, a numerical study of the heat sink with a change in the aggregate state of the oil is carried out. Simulation was carried out in Ansys Fluent CAD for two modes, static - with constant heating of the oil at 340K and dynamic, at which the heating temperature varied with time from 340K to 270K. Heat transfer in the event of a change in the aggregate state of a substance is widely used in cases where it is necessary to achieve the maximum efficiency of heat exchange. In this case, the energy is expended on the phase transition of the substance, for example, to evaporation from the liquid phase. The advantage of the heat-sink design described in this work is a rather high rate of heat transfer, greater resistance to various influences, including mechanical ones, which is primarily ensured by the simplicity of construction, eliminating the drawbacks of classical designs, which are cumbersome (the presence of an external cooling circuit ) and the limited rate of heat transfer.

    Keywords: heat dissipation, numerical methods, aggregate state, computational experiment, heat exchange efficiency

  • A complex method for measuring the permittivity in the low-frequency and microwave ranges

    In this article, we propose the idea of ​​creating a complex sensor for measuring the dielectric parameters of liquid substances in order to distinguish samples with small changes in the parameters in low-microwave ranges. The measurements are carried out by a capacitive method. For measurement at a low frequency, a capacitor-to-code converter is used; in the microwave method, a vector analyzer is used for the measurement. As a capacitive sensor, a interdigital capacitor is used that has geometrical and electrophysical parameters, in which it is not a radiating structure in the range of controlled frequencies. To combine the low-frequency and microwave methods in one sensor, a frequency-isolation scheme is used. The urgency of the method lies in the absence of the need for separate measurements of the sample with the help of various sensors.

    Keywords: interdigital capacitor, coaxial probe, frequency isolation circuit, liquid substance, sensor, model, reflection coefficient, electrical capacitance, capacitor-code converter

  • Example of calculation of an oval element of a three-layer construction filler

    In this article, we propose a method for determining the reactive load for an element of the oval rod type with a rectangular or square cross-section, in which the diagrams of the moments of external forces and single loads are rectilinear. In this case, integration can be performed analytically

    Keywords: energy-absorbing element, plot, rod, filler, load, beam, hinge, travel speed, layer

  • A method for improving the convergence of a single-center decomposition of a molecular orbital

    Investigation of the interaction of electromagnetic radiation with molecular systems gives most of the information about their structure and properties. Interpretation of experimental data is directly determined by the knowledge of the structure of energy levels and its change in the transition of these systems to an excited state. A key task of the methods for calculating the molecular orbitals of excited states is to accurately describe the emerging vacancies of the molecular core, leading to radial relaxation of the electron density. A method is proposed for an exact description of the electron density of a molecular system near its nuclei, which provides solutions to the problem of slow convergence of molecular orbitals in a single-center representation. The implementation of the computational procedure is examined using the example of a diatomic hydrogen fluoride molecule. The energy characteristics of the ground and ionized states of the molecule are estimated

    Keywords: single-center method, molecular orbital, excited state, ionized state, deep shell