Showing papers in "Herald of Dagestan State Technical University. Technical Sciences in 2022"
TL;DR: In this article , a method was developed for determining the coordinates of an earthquake source with a known structure of the earth's crust using points of various figures of the n-th order as geometric locations in calculations.
Abstract: Objective. The aim of the study is to develop methods for determining the coordinates of the hypocenter of an earthquake with a known structure of the earth's crust. Method. To solve the problem, the brute force method, the confidence interval, the comparative method and the enumeration of possible options on the grid are used. Result. A method has been developed for determining the coordinates of an earthquake source with a known structure of the earth's crust using points of various figures of the n-th order as geometric locations in calculations. Conclusion. The proposed method, with the known structure of the earth's crust, makes it possible to use all known methods that require information on the travel time differences of seismic waves to spaced seismic sensors and the difference in travel times of longitudinal and transverse seismic waves to the seismic sensor for calculating the coordinates of the earthquake hypocenter. The accuracy of determining the coordinates of the earthquake hypocenter depends on the quality of determining the structure of the earth's crust on which the seismic event was observed.
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TL;DR: In this paper , the experimental set-up and measurement procedure of laboratory thermoelectric system for electronic circuit boards cooling was described, and it was found that the use of a cooling system reduces the temperature of heat-generating elements to acceptable values.
Abstract: Objective. The purpose of the study is to illuminate the obtained experimental research data, measurement technique, as well as the design of a la-laboratory bench for full-scale tests of thermoelectric system (TES) for uneven cooling of electronic boards.Method. The article describes the experimental set-up and measurement procedure of laboratory thermoelectric system for electronic circuit boards cooling. The experimental stand is made on the basis of the measuring equipment of the laboratory of semiconductor thermoelectric devices and devices of Daghestan State Technical University.Result. We obtained plots of time dependences of temperature changes in thermoelectric system checkpoints at different thermoelectric battery (TEB) supply currents. Determined were the temperature dependences of the thermoelectric elements of the electronic board simulator at their non-uniform cooling on the parameters of FEB and working substance as well as the time variation of the temperature of the shell of the vessel with the working agent.Conclusion. As a result of full-scale tests of the device it was found that the use of a cooling system reduces the temperature of heat-generating elements to acceptable values. In particular, the temperature of heat sources decreases to 345 K and 344 K (from 428 K and 396 K) if the total heat-generating power of the electronic board is 120 W. At the same time, the temperature background created by the heat-generating elements in the nearby areas of the electronic board simulator also decreases. The discrepancy between the results of calculations carried out beforehand and the experiment was estimated to be 8%.
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TL;DR: In this paper , the bearing capacity of two-layer reinforced cement shells for force and temperature effects in a fire has been investigated, and the results of numerical simulation of full-scale experiments in the fire chamber for single-layer and twolayer shells are presented.
Abstract: Objective. Development of a method for calculating the bearing capacity of twolayer reinforced cement shells for force and temperature effects in a fire. These structures consist of a fire-retardant layer made of vermiculite concrete, as well as a carrier layer of fine-grained concrete reinforced with mesh.Method. The solution is carried out in a physically nonlinear formulation using the deformation theory of concrete plasticity by G.A. Geniev. In obtaining the resolving equations, the theory of shallow shells by V.Z. Vlasov is used. The physically nonlinear problem reduces to the sequential solution of elastic problems for a structure whose physicomechanical parameters are functions of the x, y, z coordinates. The solution is carried out by the finite element method in combination with the Newton-Raphson method. The dependence of the characteristics of construction materials on temperature is taken into account. The temperature field is assumed to be a function of only one z coordinate, and the finite difference method is used to determine it.Result. the results of numerical simulation of full-scale experiments in a fire chamber for single-layer and two-layer shells are presented. Some deviations are revealed, caused on the one hand by inaccuracies of the experiment and errors of the theory on the other hand.Conclusion. A significant influence of the boundary conditions on the process of deformation of the structure was found. When the support contour was fixed along x and y, a shell bend up was observed, which was consistent with experimental data, and in the case of a freely sliding support contour, the structural points moved exclusively downward. In general, the agreement between the results and experimental data is quite good, which allows us to use the methodology for calculating real structures.
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TL;DR: In this article , the effect of a significant increase in the rigidity and bearing capacity of a lenticular membrane-pneumatic system is observed for large spans, including racks at individual points of the span, using the step-iterative method of parameter increments.
Abstract: Objective. The purpose of this study is to substantiate the methodology for static calculation of light coatings for large-span structures with lenticular membrane-pneumatic lenses, including racks at individual points of the span, using the step-iterative method of parameter increments.Method. The study involves the phased application of the finite element method (FEM), the universal equation of state of gas and the improved Euler-Cauchy numerical procedure, taking into account the geometric nonlinearity of systems and the physical nonlinearity of the elastic work of air in lenses and taking into account the aftereffect of excess air pressure.Result. A comparison is made in terms of rigidity and load-bearing capacity of membrane-pneumatic lenses, reinforced with individual posts, with the corresponding flexible membrane-pneumatic lenses of the classical type.Conclusion. In the presence of racks, the effect of a significant increase in the rigidity and bearing capacity of lenticular membrane-pneumatic systems is observed for large spans. The distance between the posts along the building can be adjusted during the design and thereby regulate the effect of strengthening the system. The maximum deflections of the lenticular-shaped membrane-pneumatic system reinforced with struts are much less than the maximum deflections of the lenticular membrane-pneumatic system of the classical type under the action of the calculated snow load of the first and second limit states.
1 citations
TL;DR: In this paper , a method for determining the velocities of seismic waves on the ground using artificial neural networks is proposed, which makes it possible to determine the structure of the earth's crust more accurately than previously proposed mathematical methods.
Abstract: Objective. The purpose of the study is to determine the velocities of seismic waves on the ground.Method. To determine the velocities of seismic waves in different parts of the earth's crust, using a sample obtained by mathematical modeling, an artificial neural network was trained. Using at the input of the trained neural network, the real values of the differences in the times of arrival of seismic waves on the ground, we obtain at its output the values of the velocities of seismic waves on the ground.Result. A method for determining the velocities of seismic waves on the ground using artificial neural networks is proposed. Dependences of the root-mean-square error in determining the velocities of seismic waves on the ground on the training epoch, as well as the distribution of errors in determining the coordinates of the earthquake hypocenter using the obtained information about the structure of the earth, are obtained.Conclusion. The proposed method makes it possible to determine the structure of the earth's crust more accurately than previously proposed mathematical methods.
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TL;DR: This intelligent adaptive training system of design of modules based on PCB enables learners to assess their own performances and is suitable not only for training shipyard personnel to work, but for teaching various levels of training of personnel of any industrial enterprise.
Abstract: Objective. The article studies the problem of adequate assessment of the level of acquired knowledge and skills with design of modules based on printed circuit boards (PCB) using CAD PCB. The article considers the issue of assessing the effectiveness of the use of an intelligent adaptive training system, which is the fundamental criterion for the effectiveness of the training process for designing of modules based on PCB. This intelligent adaptive training system of design of modules based PCB enables learners to assess their own performances. The main purpose of the study is to substantiate the algorithm and mathematical models of the developed system for assessing the effectiveness of training using an intelligent adaptive system. Method. The parameters, algorithm and patterns of building intelligent adaptive learning systems for designing modules based on PCB of ship integrated control systems for future specialists are disclosed. Result. The target indicators of the effectiveness of training in the design modules based on PCB are highlighted. A fully functional algorithm for assessing the effectiveness of learning the design modules based on PCB in intelligent adaptive systems is determined by the step of technological operations to ensure the uniformity of the learning quality control. Conclusion. This system can be useful for teachers and specialists-studying the design modules based on PCB. This system can be used at the stage of assessing the achievable characteristics which can significantly speed up the learning process. The research methods are applied in training the design modules based on PCB to the personnel of the shipyard X52 in Vietnam. It is suitable not only for training shipyard personnel to work, for teaching various levels of training of personnel of any industrial enterprise, for example, in aircraft engineering, mechanical engineering or instrument making, and for teaching any CAD system in general.
1 citations
TL;DR: In this paper , an automated calorimetric stand that allows simulating the operation of an energy-efficient two-evaporator refrigeration unit of a household refrigerator or freezer is presented.
Abstract: Objective. The aim of the work is to develop a calorimetric stand that allows simulating the operation of an energy-efficient two-evaporator refrigeration unit of a household refrigerator or freezer.Method. In the course of the work, a calorimetric setup is described that allows conducting experimental studies to determine the cooling capacity and energy efficiency of a modernized refrigeration unit of a household refrigerator.Result. Currently, new resource-saving circuit solutions for household refrigeration equipment have been developed. The developed solutions make it possible to increase the efficiency of the refrigeration unit, as well as to reduce its energy consumption. Theoretical calculations confirming these indicators have been carried out. To confirm the calculated values, automated experimental studies are required to determine the parameters of the refrigeration unit. The paper proposes a description of an automated calorimetric stand that allows simulating the operation of an energy-efficient dual-evaporator refrigeration unit of a household refrigerator or freezer.Conclusion. The designed calorimetric stand will allow carrying out complex experimental studies to determine the cooling capacity of the modernized refrigeration unit when operating on various refrigerants. The experimental setup also makes it possible to measure the temperature and pressure during the operation of the refrigeration unit, as well as to determine the influence of various factors on its characteristics.
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TL;DR: In this article , an active thermal non-destructive determination of the main thermophysical properties of structural building materials and products, as well as an experimental setup for its implementation, make it possible to study the entire range of thermal characteristics under various conditions and modes using a thermal imager and related instrumentation.
Abstract: Objective. The purpose of the study is to improve the technical procedure and increase the accuracy of determining the key thermophysical characteristics of building materials and products in a stationary thermal regime, as well as expanding the possibilities of using integrated thermal imaging monitoring in assessing the heat-conducting qualities of heterogeneous single-layer building structures, which are, including in non-stationary temperature conditions. Method. The methodological basis of the study is the fundamental provisions of the theories of heat transfer, thermal control and infrared diagnostics, methods of qualitative and quantitative analysis of thermograms.Result. The scheme of complex non-destructive diagnostics of the thermal and technical condition of heat-protective shells of capital and completed construction facilities, engineering and technical systems and subsystems of life support for various functional, technological, operational purposes based on the results of thermography and qualitative and quantitative assessment of thermal images is presented. Examples of the use of thermal imaging equipment and other auxiliary control and measuring equipment in the field examination of translucent structures and non-translucent ventilated facade systems of a real civil building are given, as well as the results of thermal imaging identification of the main thermal properties of a fragment of an enclosing building structure in the form of a wall of silicate brick. Conclusion. The presented method of active thermal non-destructive determination of the main thermophysical properties of structural building materials and products, as well as an experimental setup for its implementation, make it possible to study the entire range of thermal characteristics under various conditions and modes using a thermal imager and related instrumentation.
1 citations
TL;DR: In this article , the dependences of the width of the radiation pattern on the curved Vivaldi antenna with a mirror arrangement of the petals are obtained, and the resulting mathematical model makes it possible to obtain the values of the radius of the curve, the opening and the lower height of the antenna lobes for different frequencies.
Abstract: Objective. The aim of the study is to build and optimize a computer model of the antenna using software packages for electrodynamic modeling.Method. The study is based on dynamic modeling methods.Result. In this paper, the dependences of the width of the radiation pattern on the curved Vivaldi antenna with a mirror arrangement of the petals are obtained. Graphs of the dependence of the radii of curved petals and aperture values on the width of the radiation pattern in two planes for frequencies of 3 and 24 GHz are plotted. Curve radius, antenna aperture and lower antenna height are plotted as functions of the maximum beamwidth for 24 GHz and the minimum beamwidth for 3 GHz. The obtained dependencies were approximated for two planes θ = 900 (antenna aperture plane) and φ = 00 (plane perpendicular to the antenna aperture plane). By means of regression analy sis, analytical descriptions and graphs of dependences of the maximum beamwidth for 24 GHz and the minimum beamwidth for 3 GHz, on the radii of the curves, aperture and the height of the lower curve of the antenna lobe were obtained.Conclusion. The resulting mathematical model makes it possible to obtain the values of the radius of the curve, the opening and the lower height of the antenna lobes for different frequencies, as a result, to build a Vivaldi antenna with the desired topology.
TL;DR: In this paper , the authors discuss where network security begins, and describe the general measures taken to secure it, and propose deployment of a private network system that is designed and serves a specific group of people for communication, collaboration and sharing.
Abstract: Objective. Network security systems are one of the key players in today's business life. Some networks are private while others are open to the public. Whether your network is private or public, it must be well secured and secure. In this article, we will discuss where network security begins, and describe the general measures taken to secure it.Method. The study is determined by the need to solve the problem of algorithmic and mathematical support for assessing the functional security of a network based on system modeling and finding erroneous positions.Result. Proposed deployment of a private network system that is designed and serves a specific group of people for communication, collaboration and sharing.Conclusion. The proposed methods can be effective in protecting the network from attacks and other security threats. Well-designed corporate policies are critical to defining and controlling access to various parts of the network.
TL;DR: The development of this scientific application would make it possible to establish the appropriate value of the indicator of the permissible risk of the implementation of threats to information security, since at the moment the method of quantitative assessment of damages is insufficiently developed.
Abstract: Objective. Assessment of the consequences of the occurrence of damage cases in the information and technical systems (ITS) of the internal affairs bodies (ATS) requires the use of an analysis of the risks of damage as a result of the implementation of information security threats.Method. In order to analyze the processes occurring in the ITS, as a rule, mathematical modeling is used. For ITS, due to the high technological complexity, high costs for the acquisition, maintenance of equipment and payment of wages to employees, it is necessary to apply the procedure for analyzing the risks of ITS ITS. The security of the functioning of the ITS ITS is normative, since at the moment the method of quantitative assessment of damages is insufficiently developed. The development of this scientific application would make it possible to establish the appropriate value of the indicator of the permissible risk of the implementation of threats to information security. Analytical and mathematical modeling using the apparatus of queuing systems. Result. A technique for analyzing the risks of information security violations based on a quantitative assessment of the damages of the ITS of ATS is given. Conclusion. The direction of this study is relevant and requires further elaboration in order to improve the method for assessing the occurrence of damage in the ITS of the internal affairs bodies.
TL;DR: In this paper , the authors developed a repair and restoration composition of materials and a technology for restoring a tower-type object using a comprehensive instrumental technical survey on the condition of the object.
Abstract: Objective. The aim of the study is to develop a repair and restoration composition of materials and a technology for restoring a tower-type object.Method. The experimental method of destructive and non-destructive quality control of building materials was used in the work; comprehensive instrumental technical inspection of buildings and structures; visual inspection of buildings and structures.Result. A situational review of the object of cultural heritage was carried out. Physical and mechanical tests were carried out in order to select the restoration composition for masonry walls of tower buildings. The results of a visual inspection are presented, on the basis of which a comprehensive assessment of the state of a cultural heritage object is given for carrying out repair, restoration and restoration work at this object. The conclusion of a comprehensive instrumental technical survey on the condition of the object was drawn up. The composition of materials for the repair, restoration and restoration of tower-type cultural heritage sites has been determined.Conclusion. As a result of the technical survey, it was found that the general condition of the facility is emergency. A repair and restoration composition has been developed that, in its properties, is as close as possible to the original, more efficient and contributes to improving the quality of work and the durability of a cultural heritage object.
TL;DR: In this paper , the analysis of the post-critical behavior of structures based on the solution of the problem in higher approximations and from the fundamental provisions of the theory of catastrophes is generalized.
Abstract: Objective. The purpose of the study is to determine the group of the limiting state according to the condition of loss of stability of the equilibrium form of structures. Method. The study is based on the provisions of the theory of stability of equilibrium states of building structures; branching theory of solutions of nonlinear equations; perturbation method; methods of catastrophe theory.Result. The results of the analysis of the post-critical behavior of structures based on the solution of the problem in higher approximations and from the fundamental provisions of the theory of catastrophes are generalized. It is proved that the study of the stability of equilibrium forms of structures using algebraic means and geometric images of the theory of catastrophes makes it possible to unambiguously determine the type of critical bifurcation points, predict the nature of the behavior of the structure, and determine the limit state group to which the state reached by the structure should be attributed. Conclusion. It seems necessary to rename the ordinal numbers of the types of critical points of bifurcations so that they coincide with the numbers of the groups of limit states corresponding to them.
TL;DR: In this paper , the authors discuss hardware and software methods of protecting the resources of the personal data information system from unauthorized access by means of "sniffing attacks", the essence of which is to intercept data that is delivered within the observed system in the form of packets.
Abstract: Objective. The article discusses hardware and software methods of protecting the resources of the personal data information system from unauthorized access by means of "sniffing attacks"; the essence of which is to intercept data that is delivered within the observed system in the form of packets.Method. The analysis of the security of resources by the personal data information system regarding unauthorized access to data by means of "sniffing attacks" includes five conditional stages: collecting information in the personal data information system, scanning the personal data information system, gaining access to the personal data information system, securing personal data in the information system, generating a report; at the same time, security analysis it is always associated with unauthorized access to data.Result. To prevent unauthorized access to data by means of "sniffing attacks", the following software and hardware solutions are proposed to minimize the consequences of unauthorized exposure to the personal data information system: the use of the HTTPS protocol, a secure version of the HTTP protocol; the use of a static ARP table generated manually; scanning of the computer network of the personal data information system by the AntiSniff program; encryption of the computer network traffic networks of the personal data information system.Conclusion.The presented hardware and software solutions allow minimizing the consequences of unauthorized impact on personal data information systems.
TL;DR: A method aimed at identifying failures and building small spacecraft sensor emulators based on the analysis of stable indicators: correlation and covariance coefficients is proposed and tested and makes it possible to increase the overall reliability of the information-measuring system of a small spacecraft (SC).
Abstract: Objective. The aim of the study is to build emulators of the main sensors of a small spacecraft (SC).Method. The quality of recovery is determined by the standard deviation (RMS) of the data from the standards. The study is based on the application of the dynamic programming method.Result. A review of works in the field of application of stable characteristics - invariants, in the applied areas of pattern recognition and state control of complex technical systems is carried out. A method aimed at identifying failures and building small spacecraft sensor emulators based on the analysis of stable indicators: correlation and covariance coefficients is proposed and tested. The proposed approach makes it possible to increase the overall reliability of the information-measuring system of a small spacecraft (SC). In the future, to emulate a failed sensor, it is planned to use multiple correlation of time sequences.Conclusion. In the general case, recognition is reduced to comparing the graph structures of objects to the correct matching of hierarchical image models based on various invariants. Control of the states of complex systems is based on the use of stable characteristics that act as invariant or subinvariant descriptors. Invariants in various applications help to recognize the current situation with a sufficient degree of accuracy, usually reducing the dimension of the problem.
TL;DR: In this paper , a methodical approach to the quantitative assessment of the risks of the implementation of unauthorized access to the information resource of the ATS AS and obtaining data in a quantitative representation is based on the use of mathematical modeling methods.
Abstract: Objective. A characteristic feature of the current stage of development of the sphere of informatization of internal affairs bodies (OVD) is a significant increase in the volume and variety of types of service information of limited distribution, stored, processed and transmitted in automated systems (AS). This gives rise to the emergence of a large number and expansion of the range of threats to information security, primarily threats associated with unauthorized access (UAS) to the information resource of the ATS AS, and necessitates the improvement of existing methods to combat this type of crime in order to ensure the information security of objects of informatization of ATS. To obtain information that allows assessing the degree of threats, it is necessary to conduct a quantitative risk assessment.Method. The method for assessing the risks of implementing threats of unauthorized access to the information resource of the ATS AS and obtaining data in a quantitative representation is based on the use of mathematical modeling methods. The advantage of a quantitative assessment compared to a qualitative assessment is the ability to compare risks with the final result, which can be represented in monetary terms, and further use in assessing the likelihood of information threats and calculating the damage caused.Result. A methodical approach to the quantitative assessment of the risks of the implementation of UA threats to the information resource of the ATS AS is proposed, which makes it possible to assess the level of security of service information.Conclusion. The proposed methodological approach to quantitative assessment of the risks of the implementation of UA threats to the information resource of the ATS AS provides a visual representation in monetary terms of the objects of assessment (damage, costs). These calculations can be used to justify the requirements for the level of security of ATS ASs during their development and operation.
TL;DR: In this paper , a method for calculating air-supported double-belt membrane-rod systems for covering large spans by the iterative method of parameter increments using FEM and the Euler-Cauchy numerical procedure of the third order of accuracy has been developed.
Abstract: Objective. The purpose of this study is to create a light, sufficiently rigid bearing coating, which can be strengthened by the air-supporting effect during overloads during force majeure. These structures can be erected in a very short time, both in combat conditions and during natural disasters. Method. The study was carried out in the software package "Program for calculating membrane-pneumatic structures by the step method using the numerical Euler-Cauchy procedure" according to the method of static calculation of membrane-pneumatic systems, taking into account non-linear factors. Result. A method for calculating air-supported double-belt membrane-rod systems for covering large spans by the iterative method of parameter increments using FEM and the Euler-Cauchy numerical procedure of the third order of accuracy has been developed. Conclusion. In design practice, the effect of strengthening the coating due to the air-supporting effect can approximately be taken equal to three. The use of the air-supported effect makes it possible to save significant funds, sometimes reaching up to 25% of the estimated cost of the structure due to the use of structural elements of a smaller section.
TL;DR: The conducted system analysis of the state information resources of the Internet made it possible to identify the relationship between the categories of data and use them to obtain operationally significant information from open state Information resources.
Abstract: Objective. The purpose of the study is to increase the effectiveness of measures to identify, investigate and disclose offenses and crimes based on the analysis of Internet resources in order to identify and structure information suitable for intellectual analysis; identify relationships between data categories, develop a model for obtaining operationally significant information from open government information resources. Method. The study is based on the use of statistical analysis to describe the general structure of information about an individual posted in official state information resources. A categorized list of relevant web resources containing operationally significant information about a person or subject of a crime is compiled on the basis of expert assessments of law enforcement officers. To determine the relationships between data categories, a graphical-analytical method for studying information flows was used, and a graph model for obtaining operationally significant information from open state information resources was built. Result. The results of the analysis of Internet resources in order to identify information suitable for intellectual analysis are presented, their structuring is carried out, relationships between data categories are identified, and a model for obtaining operationally significant information from open state information resources is developed. Conclusion. The conducted system analysis of the state information resources of the Internet made it possible to identify the relationship between the categories of data and use them to obtain operationally significant information from open state information resources. In practice, the constructed model can be used to optimize fuzzy search. To solve this problem, it seems possible to use Kohonen neural networks or Hamming algorithms. The apparatus of neural networks will allow you to determine patterns and optimize the search for operationally significant information.
TL;DR: In this article , a mobile complex for the production of expanded clay gravel, serial and modernized equipment for expanded clay has been developed for road construction in Siberia and in the Far North.
Abstract: Objective. International practices demonstrate advantages of expanded clay in road construction in difficult climatic and geotechnical conditions. The clay is present in abundance in Siberia and in the Far North which is suitable for the production of expanded clay gravel. At the same time there is a strong deficit of the road construction materials in these regions. The aim of the study is to develop a new approach for providing claydite for the construction of northern roads.Method. The modernization of the equipment means that each unit included in the complex can be transported on existing trucks, and then mounted in a line for the production of expanded clay in the field.Result. A mobile complex for the production of expanded clay gravel, serial and modernized equipment for the production of expanded clay has been developed.Conclusion. Large units - drying drums and rotary kilns for drying and firing pellets should be divided into prefabricated sections, for example, with a diameter of 2 m and a length of 5-7 m. For the electric drive of the units, a diesel generator of sufficient power must be included in the equipment set. The productivity of one complex is from 15 thousand cubic meters of expanded clay per year and above.
TL;DR: A new aspect of the method of access of regular users to information resources of automated ATS systems, based on the use of hierarchical metrics of semantic proximity, is disclosed, significantly reduces the processing of a large amount of information and increasing the performance of automated systems.
Abstract: Objective. Currently, access to the information resource of the ATS AS is implemented through the access control subsystem of the information security facility based on the mandatory and discretionary methods of access control developed in the 70s of the last century and requiring improvement. The purpose of the study is to analyze existing methods and, on this basis, select the optimal method for regular users to access information resources of automated systems of internal affairs bodies.Method. System analysis, graph theory method, and verbal (verbal) modeling.Result. A new aspect of the method of access of regular users to information resources of automated ATS systems, based on the use of hierarchical metrics of semantic proximity, is disclosed.Conclusion. The use of a method based on semantic proximity significantly reduces the processing of a large amount of information, respectively, increasing the performance of automated systems.
TL;DR: In this article , the authors developed a precision thermoelectric semiconductor sensor with the Peltier effect, which operates in an adaptive temperature measurement mode, allowing to adjust a functional sensor to measure temperature with the required accuracy depending on the object under study, as well as stabilize the melt or boiling boundary.
Abstract: Objective. The aim of the study is to develop a precision thermoelectric semiconductor sensor. Method. In the course of the study, a balanced method was applied, based on the fact that instead of a temperature difference, the thermal module will measure the coincidence of temperatures. Result. The use of a thermoelectric semiconductor sensor practically reduces the error when measuring the temperature of the environment or the object under study. The thermoelectric semiconductor sensor with the Peltier effect can operate in an economical mode, without wasting energy for measuring the temperature. Conclusion. The thermoelectric semiconductor sensor operates in an adaptive temperature measurement mode, allowing you to adjust a functional sensor to measure temperature with the required accuracy depending on the object under study, as well as stabilize the melt or boiling boundary in a container in contact with a digital thermoelectric device.
TL;DR: In this paper , the degree of development of various types of microorganisms and their effect on the physical and mechanical properties of concrete was determined. And the results of the investigation serve as the basis for competent selection of the most effective methods of corrosion protection of concrete structures operating in biologically aggressive environments.
Abstract: Objective. Determination of the degree of development of various types of microorganisms and their effect on the physical and mechanical properties of concrete.Method. Assessment of the possibility of concrete to serve as a substrate for various types of biodestructors was carried out using the determination of moisture absorption and pH of water drawing of concrete samples.Result. Experimental mechanism of action of various microorganisms on concrete is established. Taxonomic composition of microorganisms most aggressive to concrete is determined. The impact of biofouling on the physical and mechanical properties of concrete was assessed.Conclusion. The results of the investigation serve as the basis for competent selection of the most effective methods of corrosion protection of concrete structures operating in biologically aggressive environments.
TL;DR: In this article , the displacement function of transverse sections in the longitudinal direction of the rod was found, and the spectra of natural forms and natural frequencies wn of vibrations were obtained.
Abstract: Objective. In modern technology, elastic structures of structures, machines, and technical devices are widespread. In real conditions, the rods experience oscillations from dynamic and kinematic disturbances. The aim of the work is to develop methods and algorithms for solving problems of oscillations under dynamic and kinematic disturbances.Method. The study is based on the application of the hypothesis of flat sections and the d'Alembert principle.Result. The problem of longitudinal free and forced vibrations of rods is considered. As a result, the displacement function of transverse sections in the longitudinal direction of the rod was found, the spectra of natural forms jn and natural frequencies wn of vibrations were obtained.Conclusion. A set of calculation programs has been created, which makes it possible to solve problems of rod vibrations. Spectra of eigenfrequencies wn and eigenmodes jn(x) of vibrations are obtained, and u(x, t) is found, the function of displacement of cross sections in the longitudinal direction of the rod.
TL;DR: In this paper , the authors developed a computational model of a thermoelectric system (TPS) for cooling discrete semiconductor devices (DSD), implemented in the Elcut application software package, and conducted a corresponding numerical experiment on it.
Abstract: Objective. The aim of the study is to develop a computational model of a thermoelectric system (TPS) for cooling discrete semiconductor devices (DSD), implemented in the Elcut application software package, and to conduct a corresponding numerical experiment on it.Method. A new type of DPP cooling system has been developed, which uses several TEM sections that provide heat removal from both the lower and upper surfaces of the fuel elements, which increases the heat exchange surface between the cold source and the REE element and increases the heat removal efficiency. Using the finite element method, a computational model of this system is constructed based on the solution of the problem of thermal conductivity for a multi-element structure of a complex configuration, each component of which is characterized by thermal and electrical parameters.Result. A numerical experiment was carried out using the calculation model. As a result of it, the results of a numerical experiment were obtained in the form of a three-dimensional picture of the temperature field of the DPP - TPP system when it reaches the stationary mode, as well as graphs of temperature changes over time in the center of discrete semiconductor devices at various values of the cooling capacity of the thermoelectric module (TEM).Conclusion. As a result of the numerical experiment, it was found that the proposed design of the cooling TPP fully allows solving the problem of ensuring the required temperature regime of the DPP in the range of its power up to 75 W. At the same time, the use of sections of thermoelectric modules from thermoelements identical in their geometric, electrical and thermal characteristics makes it possible to increase the manufacturability of the device, as well as to ensure its operation in optimal current modes.
TL;DR: In this article , the authors developed a methodology for an objective assessment of the environmental safety of construction sites and development areas, based on a conceptual approach to assess the environmental health of construction objects.
Abstract: Objective. The purpose of this work is to develop a methodology for an objective assessment of the environmental safety of construction sites and development areas.Method. The study is based on a conceptual approach to assessing the environmental safety of construction sites and territories.Result. A methodology for assessing the environmental safety of construction objects is proposed; the criteria for assessing the development area are determined; methods for solving the problems of development of territories and their environmental safety are proposed. As a method of assessment, the coefficient "degree of real estate concentration" was developed and adopted. The concepts of "environmental reserve", "threshold of environmental safety", "sustainable state range" are introduced, which makes it possible to reliably assess the possibilities of territories for the placement of construction objects with different technogenic potential.Conclusion. It is necessary to legislate, as a mandatory procedure, the procedure for assessing the “degree of concentration of real estate” in administrative territories, especially when planning the construction of a housing stock under the renovation program, when allocating land for new construction, when assessing the environmental impact in the design and examination of construction projects.
TL;DR: To implement the function of encrypting data and backup copies of files uploaded to the "cloud storage", it is proposed to use the Rijndael symmetric block encryption algorithm, adopted as an encryption standard according to the results of the Advanced Encryption Standard (USA) competition.
Abstract: Objective. A high-quality "cloud storage" of data should ensure the confidentiality, integrity and availability of information in the "storage". The use of "cloud storage" for storing information in backups is associated with their possible loss. Ensuring the confidentiality of information in the "cloud storage" implies that by "uploading" data to the "cloud storage", the user must be sure that an attacker will not be able to obtain information from the storage. The aim of the study is to develop an algorithm for using a cross-platform mobile application to protect information in the "cloud storage" of IS.Method. The study is based on the use of a cross-platform approach to creating applications.Result. The analysis of existing approaches and frameworks for the development of crossplatform mobile applications was carried out. It is proposed to create an application based on the Xamarin framework. To ensure the confidentiality of information, it is proposed to encrypt them before uploading data and backup copies of files. Encryption involves hiding the original type of the file from unauthorized use using crypto-algorithms, when the owner of the encryption key is the authorized user. To implement the function of encrypting data and backup copies of files uploaded to the "cloud storage", it is proposed to use the Rijndael symmetric block encryption algorithm, adopted as an encryption standard according to the results of the Advanced Encryption Standard (USA) competition.Conclusion. A cross-platform mobile application can be compiled and run efficiently under iOS and Android operating systems, encrypt files and upload them to the "cloud storage" with the possibility of subsequent decryption.
TL;DR: The potential advantages of electronic document management systems are identified, which are the improvement of documentary support for intra-organizational and external communications in order to improve the regulation and coordination of operational activities, mutual agreement and adjustment of management decisions.
Abstract: Objective. Formulate the general principles for the construction and operation of an integrated electronic document management system, as well as list the possibilities of document management automation.Method. The article is based on methods of working with electronic documents, methods of searching, processing and storing information, methods of automating various office functions.Result. The potential advantages of electronic document management systems are identified, which are the improvement of documentary support for intra-organizational and external communications in order to improve the regulation and coordination of operational activities, mutual agreement and adjustment of management decisions.Conclusion. The widespread use of electronic document management systems will make it possible to distribute their functional content as an information environment for management, control and collective interaction. There are specifics of electronic documents, especially in terms of legal force, validity, storage methods, use of open forms and recording standards for the exchange of electronic documents. At the same time, the legal justification for certifying the authenticity of electronic documents using an electronic digital signature or using a system of contracts between participants in an electronic exchange is of great importance. Electronic documents have a physical and logical structure that do not coincide with previous ideas about a document as a rigid, unchanging structure of information and its carrier.
TL;DR: In this article , the authors investigated the properties of grouting cement PCT-I100 and showed that the use of retardant additives slowed down the hardening of the system in the first 10 hours, but after setting, the cement stone quickly gained the missing strength.
Abstract: Objective. Cementing oil and gas wells at a sufficiently large depth and at high temperatures is a rather complex and energy-intensive process that requires the use of special cement. The review material on oil well cements confirms the responsibility of choosing this binder, which can guarantee the safe process of drilling, plugging and operating oil wells. The classification of well cement is given, because it is known that when cementing free space in a well, specialists face various difficulties associated with temperature changes, density differences in the earth's crust.Method. The studies were carried out in accordance with the normative documents GOST 310.3-76 Cements. Methods for determining normal density, setting time and uniformity of volume change; GOST 1581- 2019 Oil-well portland cements. Specifications; GOST 310.4-81 Cements. Methods for determining the ultimate strength in bending and compression.Result. The properties of grouting cement PCT-I100 were studied, to slow down the setting of the mortar mixture for 10-14 hours, additives "Sulfatsel" and "NTF" retarders were introduced into the binder system with mixing water. The research results showed that the use of retardant additives slowed down the hardening of the system in the first 10 hours, but after setting, the cement stone quickly gained the missing strength. The water demand of oil well cement is quite high 33–35%, which is mandatory for obtaining a mobile mortar mixture, taking into account its injection by pumps into the space of an oil wellConclusion. The purpose of grouting cement confirms the responsibility and importance of selecting a binder for plugging wells and is determined by various factors, in particular, hydrogeological conditions, temperature, groundwater level in the layers of the earth's crust.
TL;DR: In this article , the authors studied the operation of beams under the simultaneous influence of combined actions: moments at the ends, kinematic harmonic displacements of both supports, a distributed load with different amplitudes, frequencies, phases, and the presence of viscous friction.
Abstract: Objective. The aim of the study is to study the operation of beams under the simultaneous influence of combined actions: moments at the ends, kinematic harmonic displacements of both supports, a distributed load with different amplitudes, frequencies, phases, and the presence of viscous friction.Method. The study is based on solving a boundary value problem and modeling.Result. Investigated the forced transverse vibrations of beams with constant cross-subject to damping. Considered non-periodic, periodic and harmonic oscillations of the beams from vector perturbations. Examples of solutions for various conditions bearings beams.Conclusion. The author's development can be adapted to vibrations of bars of variable cross section, to vibrations of continuous-discrete bars. The resulting transfer functions make it possible to calculate building elements in the form of rods for random processes, taking into account their correlation.
TL;DR: It is shown that by varying the initial state of the cellular automaton and the structure of feedbacks as control tools, it seems possible to form binary pseudo-random streams of states with different structures, different order of flow elements, bringing their characteristics closer to random ones.
Abstract: Objective. Development of a method for organizing the process of forming flows register structure, patented by the author at the Department of DSTU, which is a cellular automaton of binary sequences with a controlled structure of "cellular" automata in homogeneous register environments. Method. To solve the set system problem, a process model was built in order to determine the factors that allow changing the sequence of flow elements. Result. When studying the most common generators of pseudo-random streams based on linear register media with modulo two adders in feedback circuits, which are "cellular" automata, it was established from the tables of environment states that the factors determining the structure of the generated streams of binary sequences are the sequence of states , are the initial state of the register of a homogeneous medium and the feedback structure determined by the transition function of the cellular automaton. Conclusion. It is shown that by varying the initial state of the cellular automaton and the structure of feedbacks as control tools, it seems possible to form binary pseudo-random streams of states with different structures, different order of flow elements, bringing their characteristics closer to random ones. Examples of the implementation of the flow structure control process are given, confirming this assumption. A typical structure of a stream shaper with a managed structure based on a homogeneous one is given.