Herald of Dagestan State Technical University. Technical Sciences
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Peculiarities of superfluid helium boiling as a cryogenic agent on a flat heater inside a vertical channel
Objective. The aim of the work is to study heat and mass transfer processes during He–II boiling as a cryogenic agent on a flat heating surface inside a cylindrical channel at immersion depths comparable to its height. Method. The study is based on the application of thermodynamic analysis methods, natural and computational modeling of processes and objects of cryogenic engineering. Result. A schematic of the experimental cell, as well as the methodology for conducting the experiment and data processing, are presented. Attention is paid to the behavior of the interfacial surface depending on various experimental parameters: pressure above the liquid surface, specific heat load and the height of the liquid column above the heating element. A classification of boiling regimes in a vertical channel depending on the visual nature of the processes at the liquid-vapor interfacial surface is proposed. Dependences of the position of the liquid level in the channel on time are constructed. All series were compared, regularities between the interfacial surface velocity, the temperature difference in the liquid and the immersion depth of the heating element in superfluid helium were revealed. A heat balance for the evaporated liquid was compiled in order to estimate heat losses into free volume. Conclusion. When developing and designing systems using superfluid helium as a cryogenic agent, one can assume the morphology of the interfacial surface and the corresponding operating mode of the system.
Research on the effectiveness of a modernized household refrigerator
Objective. The aim of the work is to determine the effectiveness of an upgraded refrigeration unit using experimental studies on a household refrigerator. Method. During the experimental studies, methods of direct measurement of the main parameters of a household refrigerator were used, as well as a comparative analysis of the indicators of an upgraded refrigerator with those of the basic model. Result. Experimental studies of a household refrigerator have been conducted. The study used the most popular refrigerants in household refrigerators: R134a and R600a. Based on the conducted research, comparative diagrams of the indicators of the coefficient of working time of the refrigeration unit, the power consumption of the electric motor of the compressor and the consumption of electric energy of the refrigerator are constructed. Conclusion. The test results of the upgraded refrigerator show that the developed scheme of the refrigerating unit of a household two-chamber refrigerator allows to reduce daily energy consumption by an average of 6-7%.
Algorithms for Modules Implementing Amplitude Impulse Modulation
Objective. The aim of the study is to develop algorithms and approaches for effective synthesis of controllers in automated control systems (ACS) that utilize amplitude impulse modulation (AIM), as well as address the shortcomings of classical synthesis methods caused by the lack of a unified methodology for designing systems with nonlinear characteristics. Method. The research relies on the generalized Galerkin method and polynomial approximation techniques to create mathematical models of different types of impulse modulators, including ideal impulse elements (IIEs), first-order amplitude-impulse modulators (AIM-I), and second-order amplitude-impulse modulators (AIM-II). These models allow for more accurate representation of real-world conditions in ACS operation and minimize the impact of traditional synthesis limitations in control theory. Result. Algorithms have been developed for converting continuous signals into discrete forms that demonstrate high conformity with expectations and required technical specifications. Conclusion. The proposed approach has been validated through computer simulations, confirming its effectiveness, and simulation results are presented.
Modification of the Random Forest Algorithm for Selecting Investment Instruments
Objective. The aim of the study is to improve the efficiency of investment decisions by developing a machine learning algorithm "Modified Random Forest" for forming an investment portfolio. Method. The article proposes a binary classification algorithm "Modified Random Forest" based on the machine learning algorithms "Decision Tree" and "Random Forest". At the first stage, the algorithm builds a decision tree based on forecasts using the naive method and the ARIMA method, and at the second stage, it forms a "forest" of trees from random subsamples. Result. The algorithm was tested on different time intervals on the instruments of the Russian Moscow Exchange index and the American NASDAQ index. To assess the accuracy of the algorithm, the Precision, Recall, and Accuracy metrics were selected. For comparison, shares were selected for the portfolio under the same conditions using the classical Markowitz problem method, the results of which for the corresponding metrics were somewhat weaker. At the same time, the proposed algorithm takes significantly less time to run, since it does not solve the optimization problem when forming a portfolio. Conclusion. The developed machine learning algorithm "Modified random forest", based on the Arima forecasting methods and naive forecast allows solving the problem of increasing the efficiency of investment portfolio management, and due to its binary nature, it can be used not only in the financial sector, but also for the task of classifying any other predicted objects.
Monte Carlo simulation of reliability of electronic components of very large-scale integrated circuits
Objective. Development of a methodology for assessing the reliability of electronic components of very large-scale integrated circuits using stochastic modeling by the Monte Carlo method for failure prediction and reliability parameter optimization. Method. The Monte Carlo statistical testing method was applied to model the degradation processes of VLSI electronic components. A mathematical model was developed that takes into account the influence of temperature, humidity, mechanical stresses and electrical loads on reliability parameters. 10 simulation iterations were performed. Result. Statistical distributions of failure-free operation time for various types of VLSI components were obtained. Temperature influences contribute most to reliability degradation (52.0%), humidity – 29.4%, mechanical stress – 22.8%, and electrical loads – 12.7%. The model demonstrates a prediction accuracy of 95.5% when compared with experimental data. Conclusion. The Monte Carlo method provides effective modeling of the reliability of VLSI electronic components taking into account multiple impact factors. The proposed methodology allows optimizing design parameters and operating modes to improve reliability by 12-15%.
Automating the Process of Assessing the Technical Condition of Exterior Walls of Brick Buildings Using Machine Learning
Objective. The aim of this study is to develop a program for determining the technical condition of buildings using machine learning. The objectives of the study include analyzing existing machine learning methods, writing program code, collecting a training dataset, determining the optimal ratio of training parameters, and determining the most accurate machine learning algorithm for the given parameters and input data. Method. The study is based on methods and algorithms for diagnosing the condition of technical systems using machine learning technology. Result. The results demonstrate that even with a limited amount of data, the program is capable of correctly and accurately determining technical condition categories, minimizing the risk of missing emergency situations, and also confirms the potential of using machine learning in construction diagnostics. Conclusion. The significance of the obtained results for the construction industry is that the use of the developed program will increase the accuracy and speed of building inspections, which in turn will improve their safety.
On the issue of ensuring information Security requirements at the University
Objective. This publication addresses a pressing issue: ensuring information security (IS) requirements for the educational process at higher education institutions (HEIs) in the Russian Federation. Method. It appears appropriate to consider IS compliance not as a separate process, but as an "integrated quality" of established management systems, such as a quality management system (QMS) compliant with ISO 9001 or a specialized management system for an educational organization (SMEO) compliant with ISO 21001. Result. It has been demonstrated that IS compliance requires only a "targeted" management system compliant with ISO 27001. However, as the author's experience in auditing HEIs has shown, this is not the only optimal option. The novelty of this publication lies in its objective examples of how well-known standards (e.g., ISO 9001 or ISO 21001) can be applied with minimal costs and effective compliance with relevant requirements. Conclusion. The implementation of the "built-in quality" principle in terms of information security assurance, which has been sufficiently confirmed during testing at universities, provides a practical basis for experts (consultants and auditors) in selecting and implementing a strategic direction in the field of conformity assessment. The obtained results can be applied by all stakeholders striving to ensure the required level of information security as part of the overall process of ensuring an effective QMS or ISMS for universities.
Application of a Genetic algorithm for the rational placement of Rectangular items
Objective. The aim of the work is to conduct a comparative analysis of the efficiency of using genetic algorithms to find a rational placement of rectangular parts based on numerical experiments. Method. There are two main methods for solving optimization problems exact and approximate. The study considers one of the directions of approximate algorithms heuristic, which are based on the assumption of the properties of the optimal solution. In particular, this article considers a genetic algorithm as a method that allows you to find such an arrangement of parts that is close to optimal. To solve the problem, small objects are specified that must be placed without mutual overlap inside large objects so that the objective function reaches a minimum. The relevance of the study of this problem is due to its belonging to the class of NPhard problems. Result. A program was developed that implements the placement of parts in a semi-infinite strip using a genetic algorithm. The behavior of this program on different classes of problems using three placement procedures was studied. The analysis of the algorithm's operation is carried out on seven categories of known test sets. Each category of input data contains three examples with a different number of elements in the range from 16 to 197. Conclusion. To solve problems of rational use of materials, the development and software implementation of heuristic approaches is a pressing issue. These methods are effective algorithms for the optimal use of resources financial, material and others. The strength of metaheuristic methods is their ability to solve complex problems without knowledge of the search space, so these methods make it possible to solve difficult optimization problems.
Asymmetric S-curves for predicting the dynamics of new technology diffusion
Objective. The objective of the study is to develop a new method for calculating the dynamics of new technology diffusion using asymmetric s-curves that takes into account the interaction and exchange of information on the success of new technology implementation between active and potential users of the new technology. Method. The methods of mathematical analysis and probability theory are used, a new mathematical apparatus is developed based on recurrent calculation methods, the calculation results are confirmed by a simulation model. The performance of the developed methods is assessed by comparing the predicted values with real data on the dynamics of new technology diffusion. Result. The paper assesses the accuracy of the forecast, and also analyzes the required relationship between the volume of analyzed data and the accuracy of the forecast for the growth in the share of active users. The proposed method also allows us to estimate the intensity of interaction between consumers of the new technology. Conclusion. The results obtained can be used to improve the accuracy of forecasting the dynamics of new technology implementation on the market. This is achieved through the use of recurrent equations designed to calculate the coefficient reflecting the intensity of interaction between users. The use of these equations allows for a more detailed assessment of the impact of interpersonal relationships on the diffusion of innovations.
Organizational and technical systems – work analysis and research methodology
Objective. This paper provides a detailed analysis of well-known publications in the field of methodology for studying organizational and technical systems in order to identify the main trends and prospects for their development, as well as to develop recommendations for their improvement. Method. The methods of induction, deduction, logic theory, analysis of scientific literature, systems analysis, comparative analysis are used, allowing to study scientific works, monographs, patents, articles devoted to organizational and technical systems, as well as modern trends in their development. Result. The article provides a detailed analysis of the works and methodology of research into organizational and technical systems, and identifies current development areas. The analysis shows that researchers pay special attention to an integrated approach to studying organizational and technical systems, taking into account both technical and organizational aspects. One of the promising areas is research aimed at teaching representations, as well as developing machine learning algorithms that can be useful in modeling organizational and technical systems. Conclusion. Based on the results of a detailed analysis of more than 300 sources, general and specific patterns, approaches to the study of organizational and technical systems based on the use of various scientific and methodological apparatus were identified. The presented analysis can be used by specialists and researchers engaged in research in the field of organizational and technical systems. In addition, this analysis will be useful for applicants conducting scientific research in this area.
Optimization of PI controller tuning in automatic control systems for complex technological processes at Nuclear Power Plants
Objective. The article focuses on the tuning of PI controllers in control systems for complex processes, such as those in nuclear power plant units. Method. The application of automatic control theory methods for synthesizing digital regulators is emphasized, simplifying the design process.Special attention is given to the advantages of tuning regulators using analytical simulators. They allow modeling various operating modes, including emergency situations, helping to eliminate issues such as integral windup or loss of stability. Analytical simulators accelerate the tuning process, reducing costs and improving accuracy. Result. Key tuning parameters are discussed: the gain coefficient (KP) and the integration time constant (TN), which affect thesystem's sensitivity and response speed. Equipment ch as heater power and measurement accuracy, are taken into account. The regulator module 1411 in the PTC TPTS-NT software-hardware complex is described, providing high precision and speed due to a cycle time of 23.3 ms and a frequency range of up to 21.5 Hz. This enables effective processing of input signals and disturbances. Conclusion. The combination of the TPTS-NT software and analytical simulators ensures high accuracy, adaptability, and reliability of control systems, which is critical for complex processes such as nuclear power plant unit control.
Organization and methodology of an experiment to determine initial data for assessing software security indicators for automated systems of internal affairs agencies
Objective. The aim of the article is to develop a methodology for conducting a full-scale experiment to determine the initial data necessary for assessing the security of software used in the information technology systems of internal affairs agencies, in the dynamics of its operation. The methodology allows for the identification of potential vulnerabilities of high and critical levels of criticality during software operation, determining the values of the time characteristics of their operation, and the average values of the times to identify and eliminate current vulnerabilities in the software. Method. To achieve the stated objective, the methods of graph theory, automated static analysis of program code, electronic chronometry, direct measurement, analysis of statistical data, and comparison were used. Result. The application of the proposed methodology yielded quantitative values of the initial data required for assessing the comprehensive software security indicator for automated systems of internal affairs agencies. This indicator includes the criticality level of a set of software vulnerabilities, the software security time indicator, the software readiness coefficient for safe operation in the presence of vulnerabilities, and the interval indicator of software security breach due to exploitation of a vulnerability of a given criticality level. Conclusion. The prospects for the practical implementation of the proposed methodology are related to the analysis and accurate quantitative assessment of the software security in use in real time based on the developed software package. This is achieved by selecting the most secure version to improve the security of restricted service information circulating at specific information systems of internal affairs agencies.
Objective. The objective of this study is to perform a software analysis of the Slowloris cyberattack and implement a protection mechanism against a Slowloris-type DDoS attack. Method. PHP was chosen for the development of the software tool, as it has established itself as one of the most popular and widely used languages in web development. The PhpStorm IDE from JetBrains was also selected along with the programming language. Result. A software mechanism for protection against a Slowloris-type DDoS attack has been developed. The mechanism has several advantages over similar approaches: the software can be used free of charge and is modifiable; it meets modern password strength requirements; it uses the HTTPS protocol for secure connections; it encrypts requests; it hashes user authorization data (login, password) and stores it in a database on the server, etc. Conclusion. The developed software tool can be used as an embedded protection mechanism for any authorization or registration pages, allowing for the automatic blocking of potentially dangerous connections.
Methodology for selecting effectiveness criteria of information Security Systems during Red Team simulated attacks
Objective. A methodology is proposed for selecting criteria for assessing the effectiveness of an organization's information security system based on conducting simulated Red Team attacks. This urgency is driven by the growing sophistication of cyberattacks and the need to test the readiness of organizations of various sizes from critical information infrastructure facilities to the financial and government sectors to withstand targeted attacks. Method. The methodology combines a comparative analysis of existing approaches, case studies of real cyber exercises, threat modeling (based on the MITRE ATT&CK matrix), and expert interviews with security specialists. Result. A review of regulatory documents (Russian GOST standards and federal laws, FSTEK guidelines, international standards ISO/IEC 27001 and NIST SP 800-53) and modern Red Team/Blue Team practices, including the use of SIEM, SOAR, and XDR systems, is conducted. A classification of security performance indicators (incident detection time, response speed, attack detection rate, etc.) is provided, illustrated with practical examples and architecture diagrams of security monitoring centers with SIEM/SOAR integration. Conclusion. Alternative approaches to assessment (audit without active attacks, pentests), limitations and risks of Red Team methods and recommendations for taking into account the results of simulated attacks in regulatory frameworks and corporate audits are provided.
Development of an interface for calculating the non-sinusoidal coefficient with adaptive window Fourier transform and the power part of the active filter in the high-voltage network of a mining and processing plant
Objective. The purpose of this study is to develop a software tool with a graphical user interface designed for analyzing and calculating the non-sinusoidal coefficient using adaptive window Fourier transform, as well as determining the configuration of the power part of the active filter. Method. Adaptive windowed Fourier transform is used to analyze the harmonic composition of current and voltage in a high-voltage network, which ensures high accuracy of spectral analysis. This makes it possible to effectively identify and evaluate the coefficient of non-sinusoidal signals. The configuration of the power part of the active filter is calculated taking into account the characteristics of nonlinear consumers and network parameters. This approach ensures that the filter parameters are determined, which significantly reduces distortion and improves the quality of electricity. Result. In the Matlab environment, a graphical user interface (GUI) has been developed using the Matlab Graphical User Interface Development Environment (GUIDE) tool. The program allows for spectral analysis and assessment of harmonic distortion levels, as well as the generation of recommendations for selecting the configuration of the active filter's power section. Conclusion. The proposed solution can be effectively used by engineering and technical personnel of enterprises to monitor the quality of electricity and reduce the level of harmonic distortion. The use of adaptive window Fourier transform allows the software package to become a universal tool for analysis tasks, and the developed configuration module for calculating the power part of an active filter in the high-voltage network of a mining and processing plant makes it possible to effectively and accurately reduce harmonic distortion.
Finite Element method application for Assessing the performance of pipelines with Geometrical defects
Objective. The aim of this study is to develop and improve methods for assessing the performance of pipelines with ovality defects to enhance the safety and economic efficiency of their operation. Methods. The modeling and refined calculation of pipelines were performed in a software package using the elastoplastic formulation of the problem with the use of the Ramberg-Osgood deformation diagram. The calculation is most approximate for deformed steels. Results. Fatigue life calculations have shown that, under operating conditions, most ovalization defects of the cross-section up to 10% retain residual service life. A method has been developed for rejecting pipes with ovality, taking into account various characteristics, allowing for more reliable rejection and evaluation of pipes with this defect. Conclusion. The proposed methods, derived from the study of the cross-sectional defect of ovality, are advisable for assessing the performance of defective pipeline sections, as well as during the technical condition-monitoring phase. The relevance is confirmed by the fact that the defect was studied taking into account many factors that affect the strength characteristics of steel.
Optimization of the layout of construction objects in space by the generative design method using the DYNAMO STUDIO development environment
Objective. The purpose of the study is to explore the possibilities of optimizing the layout of construction facilities using modern computer technologies and algorithms, such as generative design. Method. Research methods include generative design and machine learning algorithms. Result. The results of the development of a methodology for optimizing the layout of construction facilities, which can be applied in the practical activities of architects and engineers, are presented. The principles of information modeling help to increase the speed of project work without compromising its quality. This helps to prevent a lot of errors at the design stage, which in turn reduces the likelihood of problems during the construction phase of the facility. Conclusion. The complexity of the layout optimization task increases with the increasing complexity of the project and the variety of requirements that the facilities must meet. Using the Dynamo Studio development environment will allow you to create an effective software module for generating the layout of construction objects in space.
Basic approaches to assessing the Security of Information Systems and prospects for their application in the internal affairs agencies of the Russian Federation
Objective. The article analyzes the main approaches to assessing the security of information systems, highlights their advantages and disadvantages, and considers their applicability to the internal affairs bodies of the Russian Federation. The aim of the study is to determine the prospects for the development of methodological approaches to assessing the security of internal affairs bodies of the Russian Federation. Method. The present study is based on the study of various methods for assessing the security of information systems, as well as on the analysis of scientific literature and publications on this topic. Result. The authors propose an approach to the further development of methods for assessing the security of information systems, taking into account the specifics of the internal affairs bodies of the Russian Federation. Conclusion. The authors note the prospects of research in the framework of creating specialized software that combines expert knowledge and quantitative algorithms, which could simplify the assessment of the security of information systems of law enforcement agencies, ensuring accuracy, accessibility and adaptability to the specifics of law enforcement activities. Such software would be a valuable tool for improving the data security of law enforcement agencies, minimizing risks and optimizing resources, opening up new opportunities to protect critical information systems.
Statically determinate and indeterminate trusses from the standpoint of the principle of stationary action
Objective. The article considers the correspondence of statically definable and statically indefinable trusses to the general physical principle of stationary action and its specific manifestation in the mechanics of deformable solids – the generalized principles of Lagrange and Castigliano. Method. The design tasks for the farms were solved on the basis of the theory of structural synthesis using the generalized Castigliano variational principle and the Lagrange multiplier method. Isoperimetric problems with a coupling equation that establishes a given volume of material are considered. Equations for determining the variable parameters are derived from the stationarity condition of the generalized functional of the potential strain energy. For a three–core statically indeterminate truss, its degeneration into a single core was found, and for a multi-span truss, complex numbers for the desired parameters were found. Result. A generalization of Vasyutinsky's theorem, formed without taking into account the problem of stability of the equilibrium of the system elements, is given. It is established that for a statically definable truss, the minimum of the potential energy of deformation corresponds to the minimum of the volume of the material even in the presence of compressed rods. A generalization of Levy's theorem is given, taking into account the stability of the equilibrium of compressed rods, which confirmed the search for rational systems in the field of statically definable systems with global minima of the potential energy of deformation and the volume of the material. Devoid of an objective criterion of rationality, the task of synthesizing a statically indeterminate farm can be considered with a variety of subjective criteria with a local minimum of the objective function. Conclusion. To ensure global indicators of the mechanical resistance qualities of structural systems, in particular trusses, ther analysis and synthesis should be carried out on a single methodological basis using the principle of stationary action.
Algorithmization and software implementation for selecting operating parameters of pumping equipment in hydronic heating systems of residential buildings
Objective. The aim of the study is to develop and implement software algorithms for engineering calculations designed for the automated determination of the parameters of mixing, water-jet and circulation pumps used in water heating systems of residential buildings. Method. The methodological foundation of the study is based on regulatory provisions in the fields of heating and heat supply, the heat balance equation, and the principles of hydraulic calculation for heating systems. The algorithms are implemented as three interrelated software modules, structured according to a block-logical scheme: input of initial data, thermal and hydraulic calculations, and output of parameters for pump selection. The calculations are performed with consideration of the steady-state thermal regime, outdoor and indoor air parameters, hydraulic losses in the system, and the design features of the pumping equipment. Result. Three specialized software programs have been developed for selecting the operating parameters of mixing, jet, and circulation pumps used in hydronic heating systems of residential buildings. The automated determination of input and calculated parameters is provided, including maximum thermal load, mass flow rate of the heat carrier, flow mixing ratio, hydraulic head, and geometric characteristics. The structure of each software module is presented, with justification of the input data, intermediate computational results in the form of listings, and output parameters. Conclusion. Algorithms simplify and accelerate the process of selecting pumping equipment operating parameters and minimize errors in engineering calculations. The software ensures that design solutions comply with regulatory requirements and takes into account external and internal climatic conditions and building performance characteristics. They also allow calculation algorithms to be adapted to heating supply conditions, including independent connections and closing sections of systems. Automated calculations facilitate the intensification of design work and are integrated into CAD and BIM technologies.
Assessment of the Adhesion of Phosphate layer on the metal surface with roofing Waterproofing material and Polyurethane glue
Objective. Evaluation of phosphate film adhesion is necessary to increase the durability and reliability of roofs, ensuring protection against corrosion, tightness and costeffectiveness of construction. Conduct a study of the adhesive bonding of a phosphate film on a metal surface with a roofing waterproofing material glued with polyurethane glue. Method. A film was formed on the surface of St3 steel plates by treating the metal surface with a rust converter. An experimentally improved formulation of a corrosion converter based on orthophosphoric acid with the addition of Lewis acid (or acid salts) is proposed. 150x150 mm metal plates were used, to which a fleece-backed waterproofing material was adhered using roofing polyurethane adhesive. Half of the samples were treated with the corrosion converter, while the other half were left untreated, displaying old metal corrosion on the surface. The roofing waterproofing material was peeled off using an ONIKS-1.AP.005 adhesion tester according to GOST 28089-2012 and GOST 28574-2014. Result. The average adhesion strength of the phosphate film with polyurethane adhesive is 0.413 MPa, which is 4.03% higher than that of the surface of untreated metal without corrosion and 21.47% higher than that of metal with surface corrosion. Conclusion. The modified phosphate film has increased adhesion to adhesives, and in the future, possibly to paint and varnish coatings and concrete.
Efficiency of stabilizing additives in strengthening clay soils with mineral binders
Objective. Most of the territory of the Russian Federation experiences a shortage of stone mineral materials used for the construction of road base layers. As an alternative, in areas with a shortage of stone materials, it is advisable to use soils reinforced with binders. At the same time, it has been established that the use of mineral binders in their pure form has a number of disadvantages, the main one of which is the low crack resistance of reinforced soils, which is explained by their low deformability. The purpose of the work is to conduct research on the effect of two stabilizing additives «Underbold» and «Geo-R-Bond» on the physical and mechanical properties of loam when it is reinforced with cement. Method. To conduct a comprehensive analysis of the physical and mechanical properties of reinforced soil using stabilizing additives, cylindrical samples were developed and tested in accordance with the requirements of GOST 70452-2022 «Soils stabilized and strengthened with inorganic binders. General specifications». Result. A comprehensive study of the strength characteristics of soil concrete samples depending on the dosage of cement and stabilizing additives allowed us to develop optimized formulations that ensure maximum operational reliability of the material. During the experimental studies, it was found that an increase in the cement content in the soil concrete composition leads to a proportional increase in its strength indicators. Analysis of the data obtained showed that maximum strength is achieved with the introduction of 7% cement into loamy soil, which indicates that an optimal balance has been achieved between plasticity and structural integrity of the material. Conclusion. The use of the considered stabilizers in soil strengthening contributes to an increase in the tensile strength of samples when splitting, which indicates an improvement in crack resistance. In the process of a comprehensive assessment of the effectiveness of soil stabilizers, taking into account the physical and mechanical characteristics of the reinforced material and the optimal ratio of components, the most effective composition was identified. In this context, it should be noted that the optimal proportion of stabilizing agents includes 7% cement in combination with the «Underbold» additive.
Use of man-made wastes in bonding technology
Objective. Improving the quality and durability of construction materials while reducing the costs for their implementation and operation is an urgent task of building materials science. New technologies are based on the dominant position of the active binder component, responsible for accelerating the hydration processes of the binder, the targeted formation of the phase composition and changes in the structure of the cement stone. Combination of clinker and mineral parts, inclusion in the system of chemical modifiers, correct formulation design and technology of preparation of the binder composition and concrete mixture will achieve the required design strength, reduce cement consumption and cost of the product. Method. The studies were conducted according to the normative documents GOST 310.4-81 Cement. Bending and compression strength methods; GOST 310.3-76 Cements. Methods for determination of normal density, latching times and evenness of change in volume; GOST 30515-2013 Cements. General technical conditions. GOST 10180-2012 Concrete. Methods of determination of strength by reference samples. Result. A complex pozzolanic additive has been obtained, the material composition of which will allow for the creation of a denser stone structure, due to an additional active source of unhydrated calcium silicates, sodium and calcium aluminosilicates. The resulting filled binding agent has properties that are higher than those of the control samples. Using local inert material and saving 25% of clinker share developed heavy concrete compositions classes B20-22.5, widely used in the filling of foundations, slabs, stairways, tiles and other concrete and concrete products. Conclusion. The proposed research results will make it possible to successfully implement projects of global importance, creating sustainable, durable and long-lasting concrete structures. The work was carried out within the framework of the state assignment of the Grozny State Oil Technical University named after acad. M.D. Millionshchikov FZNU-2024-0003 "Development of a set of low-carbon technologies for increasing the productivity and sequestration potential of the ecosystem in urban areas with the production of secondary composite materials for multifunctional purposes".
Study of strength characteristics of lightweight shotcrete mixtures from local mineral raw materials depending on heating temperature and amount of finely ground additive
Objective. This article presents the general principles of producing lightweight, heat-resistant shotcrete mixtures using diatomaceous earth aggregates and expanded clay sand on a composite binder of Portland cement with finely ground additives of fired shale and argillite clays and broken ceramic bricks. The aim of the study is to determine the influence of the type and dosage of mineral additives and the heating temperature on compressive and flexural strength. Method. High-tech equipment, research and testing methods regulated by regulatory documents, in combination with research techniques, and methods of mathematical experimental design were used. Result. The compressive and flexural strength of heat-resistant shotcrete mixture samples was determined to identify and select the optimal composition for protecting concrete lining structures from exposure to high temperatures. Conclusion. The developed shotcrete compositions based on a composite binder made from local mineral raw materials exhibit satisfactory physical and mechanical properties and are consistent with the results of other studies, making them promising for strengthening building structures and protecting against high temperatures. The results confirm the feasibility of using these compositions in construction.
Objective. This article examines the operational characteristics of trusses with the aim of determining the optimal number of different elements in truss design. Method. The study is based on analytical methods for calculating the strength, rigidity, and stability of conventional and trapezoidal trusses. Theoretical research is used to determine steel consumption depending on the number of different truss elements. A numerical example of determining steel consumption for an 18-meter truss span is provided. Result. A calculation method and study of the performance of conventional and trapezoidal trusses are presented. Steel consumption for all types of structures is determined, tables are compiled, and graphs with steel consumption curves are constructed. The considered design and calculation schemes allow us to determine the optimal number of different truss elements, which ensures a minimum steel consumption per structure. Conclusion. Based on the presented results, the optimal number of different elements can be determined at the truss assembly stage.