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  • Schemes of external and internal reinforcement and a technique for strengthening compressed and bending reinforced concrete elements with carbon fiber

    This work is a continuation of a scientific study to determine the effectiveness of composite materials based on carbon fabric in the field of strengthening bending and compressed elements. The article is devoted to the determination of the geometric characteristics of prototypes, the description of the structure of the internal metal frame and the methodology for strengthening reinforced concrete samples. The importance of this scientific work lies in the fact that one of the most popular companies selling composite materials in Russia (“Gidrozo”) proposes to use a new technology for reinforcing reinforced concrete structures that differs from that recommended in the norms. However, according to the manufacturer's specialists, this technique not only ensures reliable adhesion and joint operation of reinforcement materials and structural concrete, but also significantly increases the efficiency of the composite material.

    Keywords: steel, heavy concrete, reinforced concrete, composite material, reinforcement, carbon fiber, test, stand, beam, sample

  • Blockchain as a service for protecting information about the authenticity of educational diplomas

    The problem of fake diplomas of education causes alarm and concern to society. In the digital age, falsification has reached great proportions. In this regard, a mechanism for recording and confirming the authenticity of diplomas using technology is proposed. A sector-token method of accessing a blockchain record is proposed. The recording technology and the blockchain formation model are shown. The proposed technology guarantees that the diplomas are genuine, protected from forgery, belong to the specialists who received them.

    Keywords: blockchain, data protection, diploma forgery, educational institution, authentication

  • Review of methods for detecting faults in a permanent magnet synchronous motor

    Overview of existing methods for diagnosing faults in synchronous electric motors and methods for their detection. Classification and analysis of existing methods, their applicability in detecting faults, advantages and disadvantages. Three classes of possible faults in synchronous permanent magnet motors are considered and described: electrical faults, mechanical faults, and demagnetization. The article discusses three classes of diagnostic methods: based on the construction of a mathematical model of a real electric motor and modeling its errors, based on processing signals from sensors, and intelligent methods based on processing collected data using artificial intelligence. The following error detection methods based on modeling are considered: detection based on the model of the electrical schematic, based on the analytical model, and based on the digital simulation model. The following frequency-time analysis methods of the obtained signals from the sensors are considered: analysis using fast Fourier transform, short-time Fourier transform, wavelet transform, Hilbert-Huang transform, and Wigner-Ville distribution. The following intelligent diagnostic methods are considered: diagnosis using convolutional neural networks, recurrent neural networks, support vector machines, fuzzy logic, and sparse representation.

    Keywords: Synchronous motor with permanent magnets, faults of electric motor, modeling, fast Fourier transform, wavelet transform, Hilbert-Huang transform, Wigner-Ville distribution, neural networks, fuzzy logic, support vector machine, sparse representation.

  • Features of the stress-strain state of normal sections of reinforced concrete beams with concrete of frame structure in a compressed zone

    The results of studies of two-layer reinforced concrete beams with a layer of various thicknesses of high-modulus concrete of the frame structure in the compressed zone and traditional heavy concrete in the rest of the section are presented. The stress-strain state of normal cross sections along the height of the beam was estimated by the values of relative deformations at the level of stretched and compressed reinforcement using the hypothesis of flat sections and actual compression and calculated tensile deformation diagrams of concrete. The influence of the thickness of a layer of high-modulus concrete on the nature of the stress-strain state between the layers is shown. The possibility of destruction of the beam on the concrete of the compressed zone was revealed due to the abrupt decrease in the actual height of the compressed zone due to the "shooting" of a layer of high-modulus concrete with its thickness less than 0.1 h0. The dependence of the relative actual thickness of the compressed concrete, i.e. the distance from the edge fiber of the compressed concrete to the neutral axis, in the studied beams on the magnitude of the bending moment is obtained. It is established that for single-layer beams, with a difference in the elastic modulus of concrete up to 20%, the dependences of the relative actual thickness of the compressed concrete layer on the bending moment are almost identical. In the studied beams, the limiting state of which is caused by the fluidity of the reinforcement, the thickness of the compressed concrete layer was 0.37 ...0.4 with a relative moment value of 0.5, and 0.33 ...0.36 with a maximum bending moment value.

    Keywords: double-layer reinforced concrete beams, normal cross-sections, nonlinear deformation model, high-modulus concrete, neutral axis coordinate

  • Using the Monty Hall paradox in project management tasks. Part I. Optimal choice of a strategy for increasing the innovative potential of an enterprise

    In this paper, we investigate the possibility of applying the theory of Monty Hall's paradox in tasks that require the need for an optimal choice of a strategy for developing the innovative potential of an enterprise. The article provides recommendations for taking into account and constructive use of the effects that affect the involved experts, in particular, the Condorcet principle and paradox. The paper explores the limits of applicability of the Monty Hall paradox theory. Its applicability is determined, together with considerations about the profitability of changing the initial choice in problems with the so-called "random intelligence".

    Keywords: decision support systems, mathematical modeling, expert evaluation, Monty Hall's paradox, project management, collective assessment, Condorcet's paradox, enterprise management, assessment of enterprise characteristics, innovative potential of an enterpris

  • Development of a quadcopter control system in SimMechanics

    The article discusses automatic selection of coefficients for PID controllers of quadcopter motors based on a 3D model. This selection became possible thanks to the method discussed in the article for exporting a 3D model of a quadcopter, created in the Solidworks CAD system, into the Matlab/Simulink environment, as well as with the further use of the SimMechanics library. To select the coefficients, a quadcopter control system is also implemented to the Simulink project, the signals from one sent to the motors in accordance with their physical location. The result of the article is a flight visualization of a 3D model of a quadcopter with a control system implemented in Simulink.

    Keywords: solidworks, matlab, simulink, quadcopter, uav, pid, simmechanics

  • Possibilities for implementing the content and language integrated learning model at a university

    The article discusses the possibilities of implementing the model of subject-language integrated learning in higher education institutions, and the authors focus on their professional experience in implementing this model in Southern Federal University for undergraduates. The authors managed to highlight in detail the working options of CLIL, taking into account the specifics of the modern labor market. The authors conclude that the presented technology can and should be applied in practice while observing the principle of feasibility in the perception of professional content in a foreign language by the target audience. This approach requires the teacher to be flexible in the development of such disciplines, since their subject content is adapted in accordance with the language level of the students.

    Keywords: content and language integrated learning, social order, bilingual education, communicative approach, professionally-oriented content, didactic principles, professional

  • Development of a seven-channel laser system prototype for a multi-aperture wave-front sensor physical modeling

    The paper considers a model of a multi-aperture wave-front sensor for an active laser beam control system based on the iterative image reconstruction algorithms with limitations, particularly, on the Gerchberg-Saxton algorithm. The specifics of these algorithms is the presence of the so-called divergence factor which is characterized by obtaining “successful” and “unsuccessful” solutions, and may be clarified by stagnation conditions available (or by local extrema). The use of global optimization methods allows to avoid this constraint and to build quite an effective strategy for retrieving phase information. An experimental research was conducted to restore phase information using this method. For this purpose, a model of a seven-channel laser system with a different phase shift was developed.

    Keywords: multichannel laser systems, wavefront sensor, Gerchberg-Saxton algorithm, physical modeling, image reconstruction, phase retrieval

  • Experimental study of residual welding stresses in a butt welded joint of thick steel

    The thickness of the steel sheets used in the element was gradually increased to meet the load bearing capacity requirements of large span steel bridges. As the main method of joining heavy plate steel, welding results in significant residual welding stresses with a complex distribution. Large residual stress during welding will significantly affect the performance of steel bridges. In this work, the distribution of residual stress in a welded thick steel sheet is systematically investigated, a specimen with a thickness of 80 mm was designed and manufactured, and the residual stress of welding was measured by X-ray diffraction.

    Keywords: steel bridge, thick steel plate, welding residual stresses, X-ray diffraction method, weld joint

  • Modeling the concept of a smart home in a virtual environment Cisco Packet Tracer

    This article discusses the technology of the Internet of things, which is used to connect smart objects to the network, for intelligent control of the power system and automation of household processes. Intelligent power system management aimed at ensuring a more uniform use of electricity and minimizing energy losses during transmission and consumption of electricity. This technology is currently being promoted globally by utilities, scientific organizations, and governments. In this work, also, a conceptual model of a smart home is built in the Cisco Packet Tracer virtual constructor and diagrams of device interaction at all levels of network construction are given.

    Keywords: internet of Things, IoT, cybersecurity, automation, Cisco Packet Tracer

  • To the selection of the optimal metal truss for a pitched roof

    The article should choose a metal truss based on the initial data for pitched roofs. Defined maximum loads and deflections in each truss. On the analysis of the residually deformed state of the truss, it was concluded that the most authentic in terms of the structural members of the truss. Recommendations are given for the design of load-bearing structures of roofs on metal trusses in the manufacture of a shed roof structure.

    Keywords: truss, effort, designing, deflection, roof, load, static calculation, displacements, trapezoidal truss, Molodechno truss

  • Comparison of logistics systems of a construction organization based on the concept of Material Requirements Planning and Just-in-Time

    This article analyzes two systems of logistics for construction organizations based on the concept of Material Requirements Planning (MRP) and Just-in-Time (JIT). The main advantages and disadvantages of each system were investigated, and which of them are most effective in the current conditions were determined. Possible options for improving MTO systems are considered, as well as recommendations for the introduction of MRP and JIT into the practice of construction organizations to increase efficiency and reduce costs are proposed. The article will be useful for specialists in the field of construction and logistics, as well as for everyone who works in the field of management and optimization of business processes.

    Keywords: logistics, Material Requirements Planning concept, Just-in-Time concept, construction project planning

  • Hadamard matrices as a source of quantum computer tests

    The problem of computing symmetric Hadamard matrices of the Balonin-Siberry construction is considered. To obtain such matrices, a large number of random binary sequences are required to select three of them, which are bound by the requirements of the matrix design. Such sequences are the first rows of three cyclic blocks of Hadamard matrices. The background of the emergence of quantum computing and the advantage of quantum generation of binary sequences for subsequent selection are considered. The calculation of Hadamard matrices is proposed as a test problem for quantum computers, which allows to show quantum superiority.

    Keywords: quantum computers, qubits, random number generators, orthogonal matrices, Mersenne matrices, Kronecker product

  • Decompaction of clay soils as a result of moisturization

    This article presents the results of a study of the process of decompaction of clay soils when they are used in soil structures. To study this issue, the following factors were chosen: the dimensions of the test samples, the amount of load on the samples, swelling when soils are moistened and shrinkage when they are dried, and the loss of strength of the samples during their decompaction was also estimated. All studies with soils were carried out in laboratory conditions. In the course of the research, dependences of relative decompaction on vertical load and changes in shear forces depending on the degree of moisture during decompaction of soils were obtained. The main conclusions of the work are given.

    Keywords: clayey soil, decompaction of soils, mineralogical composition, optimal soil moisture content, density of the soil skeleton

  • Application of factor indicators in selection of construction technologies in emergency conditions

    The article contains statistics on the number of destroyed buildings as a result of emergencies that have occurred over the past twenty years. A table has been formed taking into account the factors of selection of the method of erecting buildings.

    Keywords: earthquake, construction technology, factor, selection of construction method