An algorithm is given for carrying out repair work in rooms where devices with ionizing radiation sources are located (inspection points, X-ray machines, computed tomography devices, mammographs, etc.). All stages of the work are considered: the development of documentation, the conduct of examinations, the implementation of construction and installation works, the commissioning of the object (apparatus). Practical recommendations are given on the preparation of the required design and estimate documentation and repair work. The article was written on the basis of completed research work No. 20-147.
Keywords: construction and installation works, repairs, buildings and structures, ionizing radiation sources, X-ray machines, computed tomography devices, expertise
The article discusses the ways of developing strategies of urban spaces in countries such as Singapore, Sweden, Switzerland. An extensive analysis of the strategies used by the governments of these countries to improve the environmental situation has been carried out, which can be taken as an example for implementation in the Russian Federation
Keywords: resources, energy, energy conservation, energy efficiency (EE), ecology, construction, law, MSW, development, change
This work is devoted to the problem of the shortcomings of the current regulatory and methodological literature, which complicate the conduct of construction and technical judicial expertise. On the example of the building in Rostov-on-Don, the shortcomings of the normative and methodological literature in the areas of possible use of modern equipment for the inspection of structures are shown. This lack of the necessary normative literature in the field of non-destructive testing is clearly shown. This article shows the difficulties which experts face due to the indicated shortcomings. Conclusions based on the results of the study are made.
Keywords: cconstruction and technical expertise, normative literature, methodical literature, laser scanners, non-destructive control, masonry
The key parameter of any cooling system is the heat transfer coefficient. The article deals with the issue of studying the dependence of the thermal resistance of the heat exchanger of a liquid cooling system based on ferrofluids and the heat transfer coefficient on the parameters of the fluid flow and the magnetic field in the heat exchanger. The study was carried out by numerical simulation and thermophysical experiment. A feature of the considered cooling system is the coolant. A ferromagnetic liquid based on Fe3O4 magnetites and propylene glycol is used as a coolant. As a result, a numerical model for calculating the heat transfer coefficient for an experimental liquid cooling system is obtained. The influence of the magnetic field on the thermal resistance of the system and the heat transfer coefficient of the wall-liquid at various magnitudes of the magnetic field strength is estimated. An experimental dependence has been obtained showing an increase in the heat transfer coefficient up to 12.5% when a magnetic field is applied.
Keywords: numerical model of heat transfer, liquid cooling system, Laplace equation, thermal management, CPU, ferrofluid, percolation, heat transfer coefficient, nanofluid, magnetic field, electronics cooling
An analytical model of the development and growth of embryos in a polycrystalline material during a phase transition at the intergranular slope boundary is proposed. The model assumes the presence of faces that are oriented crystallographically parallel to the forming boundary and are characterized by reduced surface energy. In this case, the faces refer to the densely packed plane of the lattice of matching nodes. The results obtained in the work on the evaluation of the parameters of the formed facets and the total testing time are confirmed by generalized experimental data.
Keywords: phase transitions, defects, microstructure, facets, boundary geometry, specific surface energy
The article discusses the effect of photon drag (EPI) of electrons in a semiconductor quantum wire (QW) with hydrogen-like impurity centers and Kane's dispersion law, located in a longitudinal magnetic field. An analytical expression for the drag current density is obtained in the effective mass approximation, and its spectral dependence is investigated for various values of the magnetic field B and the parameters of the QW upon scattering by a system of potentials of short-range impurities. It was assumed that the QW has the shape of a circular cylinder, on the axis of which hydrogen-like impurity centers are localized. It is shown that, in the one-band approximation, taking into account the nonparabolicity of the dispersion law leads to significant dynamics of the threshold of the spectral curve. The spectral dependence is characterized by a pronounced Zeeman effect. The possibility of using an ESP for the development of photodetectors of optical radiation with a sensitivity controlled in a magnetic field is discussed.
Keywords: electron dragging by photons, quantum wire, hydrogen-like impurity centers, dragging current, dipole approximation
The audit to color saturation control tools of modern computer graphics software is carried out. Under assumption of the measuring application for saturation transform, the accompanying error is defined. In the case of a virtual instrument, this error is described as a three-dimensional value and the classification of such error components is proposed. Within the framework of a three-dimensional model, the structure of a saturating toolkit total error is systematized. Properties of one component – the hue non-uniformity of conversion – were studied for 24 graphic software packages. Its peculiarity that is critical for the certain graphic information integrity aspects in the course of saturation-contrast transform was revealed. Anticorrelation of the hue non-uniformity with the previously found brightness shift was detected. As a result, the investigated software product does not guarantee the adequacy of color saturation-contrast control in image analysis tasks. The last does not allow these packages to be used within forensic expertise anyway. Results of analysis for the software package being devoid of both errors (the hue non-uniformity and the brightness shift) are presented. So the earlier announced system requirements to maintain the initial color hue and color brightness are to be supplemented by the uniformity requirement for color saturation conversion process itself.
Keywords: Software metrology, color saturation transform, saturations’ contrast, contrast enhancement errors, graphic information integrity, expert applications
The global economy growth and active industrial development are limited, among other things, by the capabilities of existing technology. The potential for improving the functional characteristics of classical materials is practically exhausted, and the widespread use of new composite materials and high-enthalpy alloys is limited by the high cost and complexity of the technological process of their manufacture and processing. Knowledge of the materials physical-mechanical, thermophysical and chemical characteristics proves that the surface structural-phase state in many cases is crucial in the processes of wear, fracture, chemical and thermal destruction. Thus, the issue of developing technologies and equipment for modifying the surface layer and creating multicomponent coatings, including nanocomposite ones, is urgent. Current article presents the results of a study devoted to the creation of a facility for such coatings deposition by plasma spraying. One of the key elements of technological equipment for this method is a vacuum chamber, which is exposed to intense thermal stress during operation. Thus, the issue of designing a cooling system is relevant. To reduce the material and time resources at the design and experimental development, the temperature state of the chamber was simulated. It is shown that to ensure safe operation, it is advisable to use water cooling. The simulation results confirm the operability of the vacuum chamber cooling system under operating conditions. The following operating parameters were determined: the inlet pressure is 0.6 MPa, the water flow rate is 2 l/s, and the mass average temperature of the outlet water is about 40°C.
Keywords: plasma spraying, thermal state simulation, vacuum chamber, cooling system
Due to the constant increase in production, new structural materials development and growing rates of non-renewable resources consumption, the issue of increasing the machinery resource is urgent. Thus, it is necessary to develop technologies for spraying coatings that improve the functional characteristics of products, in particular, impact strength, microhardness, resistance to wear, corrosion and other environmental factors by modifying the surface layer structural-phase state. These technologies application is necessary in strategically important industries, such as machine tool manufacturing, aerospace, automotive, shipbuilding, chemical, energy, etc. This article is devoted to the facility development for multicomponent nanocomposite coatings sputtering. The design and commissioning of such a facility requires a high time and material resources investment. In this regard, it is necessary to use modern computer software systems that allow simulating multiphysics processes that take place during the facility operation. The simulation of the cathode-anode unit was carried out. Based on the simulation results it was shown that it is necessary to take into account the physical processes in the interelectrode region when designing the plasma spraying unit, since the resource of the cathode-electrode unit and the productivity of the sputtering process directly depend on the parameters of the discharge and the resulting plasma jet. Thus, high temperature and current density, as well as the arc spot abrupt movement, lead to increased wear and failure of the copper nozzles. The maximum values of the temperature and velocity of the plasma jet during spraying were 32000 K and 1800 m/s, respectively.
Keywords: plasma spraying, multicomponent nanocomposite coatings, multiphysics processes, mathematical modeling
The article discusses the requirements for automated control systems in the production of Earth orientation devices. Various types of interferometers are analyzed for use in an automated control system for the manufacture of optical instruments for orientation of spacecraft on the Earth. An overview of the most common interferometer models is given, the characteristics and features of their schemes, development trends and manufacturers are discussed in detail. A comparison was made of the parameters of a number of imported and domestic interferometers suitable for use in an automated control system. The advantages and disadvantages of interferometers according to the schemes of Jamen, Mach-Zehnder, Sagnac, Michelson and Fizeau are considered. The Jamen interferometer was invented for the first time in 1856, to measure small refractive indices of gases. The Mach-Zehnder interferometer was developed on a similar principle, its main feature is that the beams of the rays obtained can be separated at a sufficiently large distance using a semitransparent mirror. In 1913, the Sagnac interferometer was invented; in its design, the light is divided by a semitransparent plate-divider into two beams, which propagate in a circle and are reduced by mirrors back to the divider. Albert Michelson in 1890 proposed an interferometer scheme, the basis of which is a light-splitting mirror. One of the most common is the Fizeau interferometer scheme, proposed in 1868. In this type of device, interference occurs in the gap between two reflecting surfaces. Based on the parameters of the problem under study, the choice in favor of the interferometer configuration according to the Fizeau scheme is justified. Interferometer OptoTL-60/125 from LLC "Optical laboratory" meets all the requirements.
Keywords: automated control system, laser interferometer, Fizeau interferometer, optics, photonics, optical production, interferometry
The paper presents an experimental study of the effect of flow pulsations on heat transfer in bundle of pipes. The regularities of heat exchange in bundle of pipes under the pulsation regime of the flow are obtained experimentally. The maximum intensification of heat exchange was 3.23 times.
Keywords: heat transfer, pulsation flow, corridor tube bundle, intensification heat transfer, shell-and-tube heat exchanger
The article is devoted to the design and specifics of the operation of an LED variable irradiation installation for growing plants. The peculiarity of the proposed installation is the periodically changing intensity of irradiation, achieved by alternately switching on and off LED radiation sources. This approach allows you to reduce the power of the power source, which leads to a reduction in the cost of the installation design, improve the quality of the products obtained, thanks to uniform irradiation of plants and reduce the energy intensity of the growing process.
Keywords: led installation, irradiation installation, energy saving, variable irradiation, control unit, microcontroller
the article analyzes the economic instruments used by states in domestic and foreign policy from the point of view of identifying the existing coercive mechanisms in modern social practices. The study revealed how states use economic instruments as the preferred means of geopolitical struggle. In addition, the work separately reflects the fact that States should preserve the right to an original socio-economic model of development. We should also not forget about the negative consequences of unilateral coercive measures. Using the method of cognitive modeling and constructing cognitive maps, the authors identify the connections in the analyzed social practices from the perspective of studying the means of geo-economic pressure.
Keywords: cyberwarfare, cyberattacks, cybersecurity risks, communication networks, transport systems, tactical, operational and strategic initiatives
The paper presents analytical estimates of the proximity of solutions to boundary value problems for elastic-creeping layered composite materials widely used in technology under long-term loading, and also gives the corresponding averaged model for such materials. The estimates show the possibility of using the averaged model over a long time interval for the problem of loading by a constantly acting force. Previously, this statement was confirmed by numerical experiments comparing solutions of boundary value problems for an effective (averaged) model and direct numerical calculation using the original model for a highly inhomogeneous layered material. Analytical estimates are based on previously obtained estimates of the proximity of solutions to stationary problems of elasticity theory. For the one-dimensional model considered in this work, the following property is established: if the constitutive relations for various phases of the composite material are written as dependences of deformations on stresses, then the coefficients for the same form of writing the constitutive relations of the averaged model are obtained as simple weighted average values of similar coefficients for individual phases.
Keywords: layered composite materials, creep theory, averaging method, evaluating the efficiency of the averaging method, asymptotically long time interval
Cryptography is the science of privacy methods. Encryption is a special case of encryption. The article discusses the issues of encryption, the use of two different methods of encrypting text phrases: the Caesar cipher and the Vigener cipher, the definitions of the alphabet and the key are given. An example of using these ciphers on two phrases of the Cyrillic and Latin alphabet is given. A program has been designed in the Java language that allows encryption and decryption. The description of the program is given. The program form includes two radio buttons for selecting the algorithm and two buttons for encryption and decryption.
Keywords: cryptography, encryption, decryption, vigener cipher, caesar cipher, java
The results of the automated evaluation of the dynamic quality of grinding machines in the process monitoring system are presented. The transfer function of the dynamic system is analytically obtained, a formula for the frequency function is derived from it, on the basis of which models of vibration spectra are constructed, in which frequencies are present that are adequate to the real vibro-acoustic vibrations of the dynamic system of the machine when processing rings. For experimental evaluation of the dynamic quality of machine tools, integral estimates of the low-frequency components of the vibration spectrum are used, characterizing the relationship between the quality of processing bearing rings and the dynamic quality of machine tools.
Keywords: dynamic quality of the grinding machine, vibroacoustic vibrations, bearing rings, processing quality, monitoring system
The article discusses the features of identifying novelty in data, as well as general methods for identifying it. Since the absence of noise in the training information is a determining factor for building high-quality classifiers on it in supervised machine learning, such a practically important special case of the search for novelty is considered, when it is determined in separate classes of training data after all outliers have been eliminated in these data. For greater definiteness, when searching for novelty, its geometric interpretation in the space of object feature values.
Keywords: data, classifier, outliers, novelty, novelty detection, geometric approach, statistical criterion
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
Refrigerating machines are designed to cover peak heat generation in public buildings. At the same time, peak loads are often short-term and most of the time the refrigerating machines operate at 40-60% of their maximum capacity. The article deals with the issues of uneven cold consumption on the example of a sports complex located in Volgograd. When designing the air conditioning system of the games hall, a cooling system with the use of "chiller-fan coils"is used. An effective solution to reduce costs is to include a cold storage battery in the cooling station circuit. The use of a cold storage battery allows you to reduce operating costs.
Keywords: cooling system, air conditioning system, refrigeration machine, cold storage, energy consumption, peak loads, variable energy consumption
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
This article discusses the importance of timely defect detecting of automated electronic car control systems for prevention of serious failures. Also the first stage of mathematic modeling mechanism is presented, it includes construction models of the dependence of the number of failures by time with various methods of diagnosting the technical condition of the car.
Keywords: diagnosting, modeling, technical service of the car, failure, automated system, electronic control unit, engine
The article presents the systems of automation of the paper-based formation of documents on academic disciplines and practices used by various Russian universities. The systems' main advantages and disadvantages are identified. The analysis made it possible to single out four currently relevant approaches to automating the formation of documents. On the basis of the results of an expert survey of lecturers of the Southern Federal University, an approach was determined that was recommended for its further implementation at the university.
Keywords: university, documents' formation, university document management, software component, paperless documents' formation, university management activities