The increasing complexities in the development of new fire-protective coatings hinder the attraction of private investments and impede the progress of innovation. The review provides an overall picture of the research and specifically illustrates the extraordinary diversity of their directions and explains the inherent reason for such diversity. The goal of this review is to establish an information foundation for a critical analysis of the feasibility of private investments in developments in this field and to show some possible ways. The wide range of choices for specific components in fire-protective coatings and the diversity of mechanisms they employ result in a factorial number of possible combinations. The variety of properties of these components and the complexity of their interactions make it difficult to assess the outcomes of their selection unequivocally without conducting experiments during the development of new materials. Therefore, confident prediction of the results of new research is extremely challenging. As a consequence, there is a broad spectrum of directions and sub-directions in ongoing developments. Summing up the results of these investigations is further complicated by the difficulty of testing materials for aging parameters and resistance to external influences. The wide range of choices for specific components in fire-protective coatings and the diversity of mechanisms they employ result in a factorial number of possible combinations. The diverse properties of these components and the complexity of their interactions prevent a definitive evaluation of the results of their inclusion in the composition prior to conducting experiments in the development of new materials. Therefore, confident forecasting of the results of new research is extremely challenging. As a consequence, there is a broad range of directions and sub-directions in ongoing developments. Summing up the results of these investigations is further complicated by the difficulty of testing materials for aging parameters and resistance to external influences. The high uncertainty in forecasting the prospects of specific developments stimulates the advancement of simulation methods for compositions and coating manufacturing technologies, as well as the prediction of their effectiveness, etc. However, these methods only provide a partial increase in the reliability of expectations. A more thorough execution of a feasibility study is recommended to substantiate venture investments. One of the additional approaches capable of enhancing its credibility is the utilization of non-traditional specialized methods for researching patent information.
Keywords: fire-protective coatings, specifically illustrates the extraordinary diversity, prospects of specific developments stimulates, simulation methods for compositions and coating manufacturing technologies
The article compares the technologies of methods of building construction in a short time, shows the advantages and disadvantages. A summary table of comparative characteristics of building construction technologies has been formed, the terms of construction of one floor for each method and the limitations of its application have been determined.
Keywords: method of lifting floors and floors, construction technology, monolithic, large-block, frame, volumetric-modular, contour, advantages, disadvantages
In the article, a mathematical model of the oscillations of an aerodynamic pendulum in the flow of a moving medium is constructed and investigated. As a model of the effect of the medium on the body, the model of quasi-static flow around the plate by the medium is adopted. According to this hypothesis, the aerodynamic forces acting on the body are applied at the center of pressure. In our problem, the pressure center is movable relative to the plate. The equations of motion for the body under consideration are obtained. The transition to new dimensionless variables has been carried out. The violation of uniqueness in determining the angle of attack at points where the air velocity of the pressure center is close to zero is shown. Envelopes for some areas of ambiguity are constructed using multiple solutions of algebraic nonlinear equations derived from kinematic relations. To do this, the coordinates of the return points are determined, the solution of the equations themselves is found, and the boundaries of the areas of ambiguity are depicted. In the mathematical package MATLAB 18, a program is written that.
Keywords: body, ambiguity area, envelopes, return points
The article is devoted to solving the problems of choosing a variant of the calendar plan in the complex development of residential microdistricts. At present, a methodology for linking construction and installation works in time and space is being developed, new methods for calculating the organization of work are emerging. Due to the constant change in regulatory requirements in construction, the essential characteristics of scheduling methods change. Variant analysis may include a sufficiently large number of indicators of the quality of the organization of complex development. Therefore, a method for comparing options and choosing the best one is proposed, which takes into account an unlimited number of indicators of the quality of work organization. At the same time, different indicators can be taken into account for different regions, as well as new ones can be added. The effectiveness of the methodology is analyzed on the example of a residential area.
Keywords: residential area, variant analysis, flow organization of work, quality indicators, regulatory requirements
When erythrocytes move along a narrow capillary, they take an asymmetric shape and roll along the capillary like a tractor caterpillar (tank - treading motion). The shape of the erythrocyte is approximated by a truncated cylinder and is uniquely determined by the diameter of the erythrocyte in the capillary, the volume and surface area of the erythrocyte. Other input parameters are the speed of the erythrocyte in the capillary, the frequency of rotation of the erythrocyte membrane, the charge of the erythrocyte, and the number of closed trajectories along which the charges move. It is assumed that the negative charges located on the membrane are equal in magnitude and distributed evenly over the membrane and move along closed trajectories together with the membrane. From the last parameters, you can find the number of charges on the erythrocyte membrane. According to the Biot-Savart-Laplace law, mobile charges generate a magnetic field in the surrounding space. Using computer calculations, the distributions of the magnetic field strength were obtained both near a single erythrocyte rolling along a narrow capillary, and near a capillary along which several erythrocytes move, at various values of hematocrit. The dependence of the maximum value of the magnetic field strength near the capillary on the hematocrit is found. In particular, it was shown that at a distance from the capillary equal to 8 capillary diameters, the maximum value of the magnetic field strength increases by a factor of 1.29–1.36 (depending on direction) with increasing hematocrit from 12.27% to 18.25%.
Keywords: mathematical model, magnetic field, charge, membrane, erythrocyte, capillary, hematocrit
The article aims to reveal the essence of the application of multi-criteria decision-making methods in relation to the process of organizing construction production. An overview of multi-criteria decision-making methods is presented. The criteria for the optimal choice of the calendar plan as the main document in the design and implementation of the construction process are described. Using the example of the initial construction schedule, alternative options are proposed and calculation is carried out using multi-criteria decision-making methods to select the best one based on the specified criteria and the situation
Keywords: multi-criteria decision-making methods, calendar plan, construction process, construction organization.
The relevance of creating a chatbot for advising applicants, promoting the university brand and raising awareness about the university is considered. The basic principles of the chatbot functioning are determined. Modeling of the sequence of processes using IDEF0 and UML is performed. The article contains a description of the chatbot algorithm. Activity and state diagrams are used to visualize this algorithm. The graphical interpretation of the logic of the interaction of the system elements is performed at the IDEF3 documentation level. A physical model for storing the data necessary for consultation is presented; the purpose of the tables obtained is described. The issues of fuzzy search by keywords are considered. The article describes the error correction process using the n-gram distance metric and the Damerau-Levenshtein metric. The functioning of the chatbot in the consultation mode when searching for keywords with errors in the user's message is demonstrated.
Keywords: chatbot, dialog system, messenger, natural language processing, fuzzy search, Damerau-Levenstein distance, n-gram
The results of research of engineering solutions for ventilation of swimming pools based on mathematical modeling taking into account real thermal loads and moisture releases are presented. The analysis of air distribution options in rooms with swimming pools for various purposes – a public swimming pool, a SPA complex and a sports pool with bleachers for spectators. Based on the results obtained in the form of distribution fields of the parameters of the air environment, the necessary changes in the schemes of the organization of air exchange are revealed. If the parameters deviate from the normalized values, recommendations have been developed to improve the state of the microclimate. These temperature distributions allow us to conclude that the air temperature near the surfaces of external fences meets the requirements that ensure their safety. conclusions on the compliance of the obtained results with the required parameters of the microclimate for rooms with high relative humidity.
Keywords: Swimming pool, ventilation, heat, moisture, air distribution, microclimate, air environment, numerical modeling
The article is devoted to the development of training systems for training specialists in automation and informatization. The structure and mathematical model of a training system (TS) were developed to control skills in training these specialists (in particular, in the basics of programming). The parameters of the mathematical model are based on the representation of knowledge about the studied objects and processes in the field of development of automated information systems, which allows using TS to automatically generate and evaluate small practical tasks for students. A prototype of TS software in the form of a web application has been developed. In a practical aspect, the use of TS in the educational process in the disciplines in the field of programming will reduce the proportion of labor-intensive work of the teacher in compiling and checking assignments.
Keywords: information technologies in education, training system, control of knowledge and skills, high-level programming languages
The article is devoted to the issue of increasing the efficiency of ventilation systems through the use of a new type of air ducts. The main advantage of microperforated textile air ducts is the possibility of supplying fresh air with laminar micro jets to the human breathing zone. The need to adapt the existing methods for calculating the main parameters of jets for the laminar regime is noted. The article presents the results on the development of a mathematical model of a stationary boundary layer for the numerical calculation of the movement and heat and mass transfer of air in a laminar microjet. A discrete analog of the generalized differential equation is derived, on the basis of which a software package is developed that allows one to determine the main parameters of laminar microjets. Verification of the developed software package was carried out, the discrepancy with the known engineering method was less than 3%.
Keywords: mathematical modeling, air exchange, microperforated textile air duct, microperforation, laminar jet, control-volume method, round jet, micro jet
The issues of developing a project for strengthening the building structures of a cable overpass after an emergency (accident) are discussed. On a real example, a description of the accident is given, the performance of work on the ghost of structures to the standard state is illustrated. The article was written on the basis of the completed research work No. 18-26.
Keywords: building structures, safety, cable trestle, emergency response, technical expertise, buildings and structures, metal structures, reinforcement project
The subject of the study is processes related to the construction of strip-shell foundations. The scope of the study is the construction of the base under the shell, providing a curvilinear contour of the structure. Traditionally, the foundation structure is placed in undisturbed soil, which, due to its physical and mechanical characteristics, can limit the scope of application of such foundations. Using the Harrington desirability function, the authors evaluated six models of soil masses with different physical and mechanical as well as technological properties. As a result of the studies, the suggested options were rated “satisfactory” or lower. In this regard, it is required to improve both the quality of the base under the shell and the technology for the construction of such foundations by using cost-efficient prefabricated soil-cement blocks.
Keywords: Buildings, strength, construction industry, foundation, construction technology
The analysis of the foundations of modern cryptographic systems is carried out. Problems of classical cryptography arising in the development of quantum computers are considered. Considered are cryptographic protocols of quantum key distribution, their advantages and disadvantages. The analysis of stands for simulation of quantum key distribution available on the market is carried out. The rationale for the need to develop a training system has been made. The authors have developed a system for modeling and demonstrating quantum cryptographic protocols BB84, B92 and BB84 (4 + 2), intended for a detailed study of the principles of quantum cryptographic protocols in dynamics. The system provides the process of work both in text and graphic form. The developed system fully meets the needs of teaching students modern quantum information security technologies.
Keywords: information security; encryption; quantum cryptography; modeling; education system
As part of the development of the stages of pre-project and design preparation, a set of procedures is carried out, starting with planning further stages of the implementation of a construction project, ending with obtaining a construction permit. The article describes the main provisions of the methodology for choosing rational organizational and technological solutions at the stages of pre-project and design preparation of an object for construction, and also presents the results of its implementation in construction practice. The methodology defines the main procedures at the stages of pre-project and design preparation of facilities for construction; factors influencing the duration of the procedures at the stages of pre-project and design preparation of facilities for construction. On the basis of the methodology for choosing rational organizational and technological solutions at the stages of pre-project and design preparation for the construction of an object, organizational and managerial models for passing the stages with determining the duration of procedures, taking into account the influence of factors, have been developed. The proposed methodology, used in the practice of the organization, made it possible to take into account the influence of factors on the duration of the stages of pre-design and design preparation of the above facilities for construction, thereby reducing it.
Keywords: technical customer, developer, stages of pre-design and design preparation of facilities for construction, organizational and technological solutions
In the modern world, the number of different complex technical systems is only increasing every year, and any system incorporates or uses a third-party communication system. Disruption of the communication system and its elements functioning can lead to a situation where a complex technical system cannot realize its functions. It is required to ensure the guaranteed functioning of the communication system and its elements. One of the ways to ensure the stable operation of complex technical systems is the implementation of the control function by the control system, while in the process of system operation it is necessary to take into account not the characteristics and parameters of individual elements that describe their operation, but the ability of the system to perform tasks and functions. The paper proposes an approach to describing the functioning of a communication system through the formation of the system functioning profile, which is a set of matrices, which is used in the control system.
Keywords: functional stability, criticality, communication system, control system, complex technical system, functions, tasks, profile, regulations