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  • Preparing a dataset for training and testing neural networks in MATLAB

    The paper proposes a method for preparing a dataset for training and testing neural networks in the MATLAB environment using the Image Processing Toolbox package of functions. An example of the implementation of this technique for preparing a dataset for training convolutional neural networks to classify wheat seeds into high-quality and low-quality classes according to its images is given. This technique was used to obtain a dataset of 900 images, which were successfully used to train and test the convolutional neural network.

    Keywords: dataset, convolutional neural networks, artificial intelligence, image classification

  • Application of effective thermal insulation materials in building envelopes based on perlite, made by the method of self-compacting masses

    In this article is considered progressive technology for producing heat-insulating materials by the method of self-compacting masses. Implementation of this method will allow obtain a significant economic effect in comparison with traditional technologies. Due to the use of the effect of obtaining excess pressure in a closed perforated form from an increase in volume during heating of pre-expanded polystyrene granules, it became possible to remove excess moisture, reduce the time of the technological process, and reduce energy consumption. This method allows to combine several processes in one operation: compaction of the mixture, heat treatment, removal of excess moisture. As a result of theoretical and laboratory research and experimental-production approbation, the possibility of implementing of heat-insulating materials of a wide range of applications with improved operational properties into mass production has been obtained. Perlite concrete is one of the effective heat-insulating material, the production of which is possible using the method of self-compacting masses. An assessment of the qualitative efficiency of perlite concrete was carried out: the thermal conductivity coefficient is within the limits required for effective heat-insulating materials. It was concluded that the use of perlite concrete in construction is promising: it is possible to reduce the drying time in 10-12 times, eliminate drying shrinkage, eliminate mechanical processing of products after heat treatment, obtain products of various configurations and volumes, with an improvement in strength characteristics at a minimum density. In this article is considered progressive technology for producing heat-insulating materials by the method of self-compacting masses. Implementation of this method will allow obtain a significant economic effect in comparison with traditional technologies. Due to the use of the effect of obtaining excess pressure in a closed perforated form from an increase in volume during heating of pre-expanded polystyrene granules, it became possible to remove excess moisture, reduce the time of the technological process, and reduce energy consumption. This method allows to combine several processes in one operation: compaction of the mixture, heat treatment, removal of excess moisture. As a result of theoretical and laboratory research and experimental-production approbation, the possibility of implementing of heat-insulating materials of a wide range of applications with improved operational properties into mass production has been obtained. Perlite concrete is one of the effective heat-insulating material, the production of which is possible using the method of self-compacting masses. An assessment of the qualitative efficiency of perlite concrete was carried out: the thermal conductivity coefficient is within the limits required for effective heat-insulating materials. It was concluded that the use of perlite concrete in construction is promising: it is possible to reduce the drying time in 10-12 times, eliminate drying shrinkage, eliminate mechanical processing of products after heat treatment, obtain products of various configurations and volumes, with an improvement in strength characteristics at a minimum density.

    Keywords: method of self-compacting masses, heat-insulating perlite concrete, electric heating, closed perforated volume, bead polystyrene, energy efficient material

  • Multidimensional mathematical model and a geometric approach to object classification

    This paper presents a mathematical model and a geometric method of image-based object classification intended to improve the accuracy of object classification by filtering out noise objects.

    Keywords: image processing, object recognition, pattern recognition, object identification, classification

  • Strength characteristics of polyethylene terephthalate fiber concrete

    This article contains the results of a study of the strength characteristics of concrete with the addition of various amounts and shapes of recycled polyethylene terephthalate (PET) fibers. In general, the use of fiber in concrete from waste PET materials (obtained by mechanical grinding), rather than heat-treated, can increase the tensile strength. The compressive strength is reduced. Industrial flex is not recommended to be used as a fiber (additive) in concrete, as this leads to a decrease in strength characteristics. Increased tensile strength is provided through the use of specially prepared PET fiber. The conducted research proved the possibility of using PET fiber in concrete from waste PET materials (obtained by mechanical grinding) PET fiber is recommended for use in concrete structures to increase tensile strength.

    Keywords: concrete, concrete matrix, fiber, dispersed reinforcement, polyethylene terephthalate, tensile strength, compressive strength

  • Phonon properties of hydrogenated carbon nanofilms

    In this work, the phonon format of graphane nanoribbons is calculated in the Hamiltonian formulaism. The geometric model is presented in the form of a graphene plane with hydrogen atoms attached to it. The unit cell of graphane contains two carbon atoms from solid graphene and two carbon atoms. The curvature of the graphene plane as a result of attachment to hydrogen atoms and hybridization of the outer electron orbitals of carbon atoms from sp2 to sp3, as well as the interaction between hydrogen atoms, are not taken into account. Analysis of the obtained phonon spectra shows that, for any type and width of graphane nanoribbons, there is a gap between acoustic and optical vibrational modes, in contrast to graphene, which can serve as an indicator for a given structure. Also, for the material under study, the values ​​of the speed of sound and the Debye temperature were calculated.

    Keywords: graphene, graphane, nanoribbon, unit cell, vibrational spectrum, dispersion equation

  • A structural and morphological approach to modeling transport and transfer complexes as public and business centers of aeropolises on an evolutionary basis

    The aim of the study is to develop an "evolutionary model" of a transport interchange complex (TIC) - as a kind of ”growth point" of an aeropolis. Methods of “prognostic” and “structural-morphological” modeling of TIC are used for reasonable planning of the growth and development of the aeropolis. Five intermediate architectural and typological models of the transport and transfer complex have been identified: 1) bus station; 2) bus station with logistics center; 3) intermodal complex station; 4) transport and business center; 5) transport and public complex. Its "structural and morphological units", which include: a) functional components; b) structural and tectonic "units"; c) communication "framework"; d) elements of the growth of the aeropolis. A similar diachronic (developing) model of a transport interchange complex ensures its phased planning, optimal functional zoning of the facility for each intermediate phase, which will allow it to be self-sufficient at the early stages of operation. architecture.

    Keywords: architecture, shaping, functioning, spatial development, transport interchange complex, transport interchange hub, transport infrastructure, aeropolis, model, structural and morphological approach, social and business center

  • Study of the characteristics of indoor air quality on the example of a higher education institution

    This article is devoted to the study of indoor air quality in a higher education institution: assessment of the distribution patterns of suspended solids by equivalent diameters (RM0.5, RM1, RM2.5, RM5 and RM10).

    Keywords: indoor air, indoor air quality, air pollution, dust, solid suspended particles, PM2.5, PM10

  • The research energy consumption in a stepper motor model

    The article describes the simulation in the Simulink environment of the operation of a stepper motor used as an electric drive of the scanning mechanism for the Earth orientation device. The purpose of the study is to determine the minimum power consumption in each range of values for inductance and resistance. If the model is found to be inoperable above certain values of the specified parameters, the measurement range narrows to an area where there is enough energy to properly work out a given angle. The simulation is based on the parameters of NEMA17 engines, in particular, NEMA 17HS3410. Voltage control in the system is carried out by means of a PI controller, the influence of the regulator on the energy consumption of the system is shown. The regularities of the formation of angular velocity of various amplitudes when working out a turn in open and closed control systems are noted. The range of electrical parameters at which the engine operates with almost the same power consumption is determined. The lowest power values at which the engine is operable are found. The results of the work are visualized in the form of three-dimensional surfaces, recommendations for the continuation of research are developed.

    Keywords: stepper motor, simulation, Earth orientation device, power consumption

  • Election of a safe depth of the reinforced concrete case for trenchless laying of the collector

    The paper presents the results of a study aimed at selecting a safe depth of an underground collector. In the scientific and normative literature there are no specific recommendations for the depth of tunneling through the existing highways. There are only recommendations for tunneling through railway embankments. Purpose of this study: scientifically substantiated recommendations for the use of reinforced concrete pipes as collector cases. The decision of problems for achievement of the objective will be carried out by means of numerical experiment - a method of finite elements.

    Keywords: reinforced concrete case, underground collector, safe depth, mathematical modeling, case structures, highway, closed method of work, trenchless laying, finite element method, subsidence trough

  • The structure of the cost of materials in ribbed reinforced concrete floor slabs with a variable section width

    The issues of optimization of ribbed reinforced concrete slabs with prestressing of reinforcement, taking into account geometric, strength and cost indicators, are considered. The study was car-ried out on the basis of an analysis of the sales market for building materials, the basics of rein-forced concrete resistance and the provisions of regulatory documents, design activities in the Russian Federation, as well as the works of domestic and foreign scientists. The research method is structural-analytical analysis taking into account the relationships of the factors under study. Analytical and graphic materials are presented, revealing the regularities between the geometric dimensions and the cost of components. The proposed method for determining the efficiency of a structure, taking into account the cost indicators of materials, indicates the feasibility of its ap-plication in design practice. Recommendations for design are given to ensure that structures of the minimum cost are obtained and that meet the requirements of strength and durability.

    Keywords: reinforced concrete, strength, structure, reinforcement, diameter, price, cost, efficiency, dimen-sions, analysis, element

  • The risk of a special purpose automated information system being in a critical condition

    The article proposes a method for assessing the risk of a possible stay of an automated special-purpose information system in a critical state, based on the synthesis of two heterogeneous mathematical models, one of which allows taking into account the intensity of DDOS attacks and the intensity of application processing, based on Markov processes, and the second is one of the forms of a formal description of protection systems, with complete overlap, in which the interaction of the "threat area", "protected area" is considered – areas of resources of an automated information system for special purposes, and "protection systems" – security mechanisms of an automated information system. The developed method makes it possible to simulate the information security tools included in the automated information system for special purposes, under the influence of DDOS attacks, taking into account both the empirical values obtained as a result of measurements or modeling, and the theoretical base of parameters specified by input data. In the synthesis of the two models, the lack of uncertainty of some of the input parameters, taking into account the values based on expert estimates, was eliminated.

    Keywords: automated information system, security assessment, queuing system, risk

  • Evaluation of the effectiveness of admixtures for dry building mixes with normalized indicators of adhesion strength to the base

    A method of selecting admixtures for the production of dry building mixes is proposed based on the results of an expert assessment of the complex indicator of the workability of application (connectivity, continuity when pulling with a toothed trowel, elasticity, quality of rollers) on a 100-point scale and the strength of adhesion to the concrete base, followed by the calculation of the specific cost of admixtures in the mixture per ton of products, respectively, by one point of workability of application and 1 MPa of adhesion strength, developed as a result of studies of adhesive mixtures made using 4 different cements, 5 water-retaining additives and 12 redispersible polymer powders. The possibility of obtaining adhesive compositions of adhesion class C 2 using redispersible polymer powders of domestic production is shown.

    Keywords: dry building mix, adhesion strength to the base, unit cost, processability of application

  • Model of distributed processing of requests by agents of decision support systems

    The article deals with modern research in the field of decision support. A model of distributed processing of requests by agents of decision support systems is proposed. The main components of the model are considered. An algorithm is built on the basis of the proposed model. A step-by-step description of the algorithm's actions is given. The main planned results have been identified.

    Keywords: decision support systems, intelligent agents, request processing, decision support model

  • Influence of a heat source from ignition on the calculated combustion curve of polyethylene foam in a fire in a compartment

    This article analyzes the calculated fire curve in accordance with the ignition heat source in the compartment. To predict the calculated fire curve, the exponential equation proposed in the previous study was compared with the heat release rate measured in a fire experiment. The lag index, which is the main factor used to predict the time it will take to reach the maximum heat release rate, has decreased in proportion to the ignition heat source.

    Keywords: fire calculation curve, pipe insulation, ignition heat source, deceleration index, heat release rate

  • Numerical analysis of heat transfer in a multi-pipe configuration for various mixtures of liquids

    In this article, we investigate the effectiveness of using multiple pipes for heat dissipation. The study assumes laminar flow under steady-state conditions. Various mixtures are numerically investigated at different flow rates. Various nanofluids flowing through multiple parallel pipes have been numerically investigated to study the effects of temperature rise. Thanks to the benefits they bring to the cooling process, nanofluids have opened up a new way to improve the performance of thermal systems. A typical nanofluid consists of a base fluid, which is usually water, and nanoparticles.

    Keywords: heat exchanger, flow tube, nanofluid, bottom heating, coefficient of friction, pressure drop