The increased fire hazard of foamed polymers hinders their widespread use in the construction industry. An effective method of reducing the combustibility of carbonizing polymers is the use of phosphorus-containing flame retardants. Therefore, investigation of the influence of phosphorus-containing flame retardants to the composition of pyrolysis products and operational properties – heat resistance, flammability, combustibility and smoke generating ability – is the important objective. In the article we have presented the results of related experimental studies. The effects of phosphorus-containing flame retardants on heat resistance and main operational properties related to fire-safety of foamed constructional polymers are examined. A correlation was found between the results of evaluating the combustibility of foams by the limiting oxygen index and the combustibility index. Optimal concentrations of phosphorus in the foamed thermosetting polymers are established. It was shown that optimal concentration of the flame retardants leads to low combustibility of polyurethane-, resole- and urea-based foamed polymers.

Keywords: foamed polymers, fire hazard, оптимальное сдержаниеreducing the combustibility, phosphorus-containing flame retardants, heat resistance, flammability, combustibility and smoke generating ability

This article presents one of the methods for analyzing the chirality coefficient of a medium depending on such parameters as concentration n, frequency f, dielectric constants of both the container material, the medium itself, and left- and right-handed spirals distributed in this material. As a result of this work, the frequency characteristics of the chirality coefficient were obtained at various concentrations of the container trace elements.

Keywords: chiral medium, Telledzhene element, chirality coefficient, dielectric constant of the medium, magnetic permeability of the medium, spiral structure, metamaterial substrate, bulk concentration, metamaterial, spiral inclusions

When developing the final qualifying paper the problem of choosing the optimal structural concept for bearing and enclosing structures. To solve it, normative technical and economic indicators, variant comparison (trial design) and other methods can be used. The objective of the present study, which is carried out as part of the final qualifying paper, is to search for and develop an algorithm that is understandable for practical use for choosing an effective (in terms of specific consumption) structural concept for a steel truss.

Keywords: optimization, specific consumption, cost value, steel truss, steel structure design, STARK ES, analysis of trusses, optimal structural concept, changing the section type, selection of an effective structural concept

This article is devoted to the study of concentrations of carbon monoxide (II), phenol, formaldehyde, aliphatic hydrocarbons in the premises of buildings, including the assessment of the regularities of their vertical distribution in the height of buildings at different times of the day from vehicles. Research is necessary to develop a program for electronic computers, which is necessary for the design of construction projects.

Keywords: помещения, оксид углерода (II), фенол, формальдегид, углеводороды алифатические, здания, время суток

An analysis of the accident rate on gas pipelines is given. Mathematical dependences of the volume of gas entering the atmosphere during the degassing of a gas pipeline section are given. Based on the existing nomogram for determining the gas compressibility factor for main gas pipelines, a nomogram for natural gas transported through gas distribution networks was constructed.

Keywords: gas pipelines, accident rate, degassing, gas bleeding, gas compressibility factor

The article analyzes the impact of the transition to distance learning on the academic performance of students of the Institute of Computer Science, Electronics and Robotics. The disciplines are identified, the development of which does not cause difficulties in the remote format and disciplines to which such technologies are difficult to apply. Based on the findings, recommendations are given to improve the quality of education at the Institute.

Keywords: quality, distance technologies, academic performance, control card, alternative attribute

the article analyzes the economic instruments used by states in domestic and foreign policy from the point of view of identifying the existing coercive mechanisms in modern social practices. The study revealed how states use economic instruments as the preferred means of geopolitical struggle. In addition, the work separately reflects the fact that States should preserve the right to an original socio-economic model of development. We should also not forget about the negative consequences of unilateral coercive measures. Using the method of cognitive modeling and constructing cognitive maps, the authors identify the connections in the analyzed social practices from the perspective of studying the means of geo-economic pressure.

Keywords: cyberwarfare, cyberattacks, cybersecurity risks, communication networks, transport systems, tactical, operational and strategic initiatives

The results of the automated evaluation of the dynamic quality of grinding machines in the process monitoring system are presented. The transfer function of the dynamic system is analytically obtained, a formula for the frequency function is derived from it, on the basis of which models of vibration spectra are constructed, in which frequencies are present that are adequate to the real vibro-acoustic vibrations of the dynamic system of the machine when processing rings. For experimental evaluation of the dynamic quality of machine tools, integral estimates of the low-frequency components of the vibration spectrum are used, characterizing the relationship between the quality of processing bearing rings and the dynamic quality of machine tools.

Keywords: dynamic quality of the grinding machine, vibroacoustic vibrations, bearing rings, processing quality, monitoring system

Refrigerating machines are designed to cover peak heat generation in public buildings. At the same time, peak loads are often short-term and most of the time the refrigerating machines operate at 40-60% of their maximum capacity. The article deals with the issues of uneven cold consumption on the example of a sports complex located in Volgograd. When designing the air conditioning system of the games hall, a cooling system with the use of "chiller-fan coils"is used. An effective solution to reduce costs is to include a cold storage battery in the cooling station circuit. The use of a cold storage battery allows you to reduce operating costs.

Keywords: cooling system, air conditioning system, refrigeration machine, cold storage, energy consumption, peak loads, variable energy consumption

At present, despite the variety of mini-loaders in terms of purpose and type of work performed, the problems associated with the technology of snow removal from roads and adjacent areas remain relevant. Along with the continuous growth of the municipal machinery fleet, qualitative changes are constantly being made to its working equipment, aimed at increasing the productivity and efficiency of the snow removal process through the introduction of new rational and technical solutions.

Keywords: mini-loader, blade, snow removal, working equipment, snow cover, compaction, hydraulic cylinders, shock absorbers

The article describes the main technological features of strengthening subsidence soils by cementation. The features of quality control of work on strengthening arrays of subsidence soils by cementation are considered. On the example of a multi-storey residential building exposed to uneven deformations, the reasons for the violation of technologies during the strengthening of the foundation soils are analyzed. The results of laboratory and field tests of soils are analyzed as part of a re-examination of the foundations fixed by the cementation method during the construction of a multi-apartment three-section residential building. The actual results of laboratory tests are compared with the values set by the project. The diagrams of the location of pits near the building are given. The photos show the presence of cement veins. The causes of uneven deformations of the newly erected object have been established based on the results of a laboratory study of the fixed subsidence soil. It is noted that strict quality control of work on strengthening subsidence soils will allow avoiding emergency consequences during the construction and operation of buildings in the future.

Keywords: cementation of soils, subsidence soil, artificial strengthening of soils, injection, geocomposite, armoelement, drilling, testing of soils, construction control

Reducing the consumption of heat resources in construction and housing and communal services is one of the key tasks solved by design engineers. The increase in the thermal protection of buildings is determined by regulatory documents, but construction customers often require it to be strengthened without any feasibility study. The objective of the study is to develop a graphical-analytical model, the analysis of which allows you to choose the most optimal combination of heat resistances of the coating (walls) and translucent structures of a particular building object.

Keywords: energy-saving project, thermal protection of buildings, "indifference" curves, the method of the fastest descent

The article offers a solution which will enable to reduce dust pollution during earthworks in urban conditions. A special multi-functional mechanism is proposed enabling to perform several important preliminary processes simultaneously - improving an environmental situation on the site of earthworks. The ground surface damping during trench opening and soil unloading from a bucket into a disposal area will make it possible to reduce the fine dust pollution of the air surrounding a work location. The objective of the study is to develop a mechanism reducing the fine dust dispersal when performing trench and pit excavation. The novelty is that a mechanism of special construction has been proposed that can be mounted onto any machine in the construction line.

Keywords: earthworks, dispersal, technology process, trenching, single-bucket excavator, soil disposal area, trench, fine dust, air pollution, РМ 2,5, PМ 10

The results of verification of turbine and rotary gas meters used as measuring instruments in gas supply systems of industrial enterprises are presented. It was found that about 50% of calibrated meters exceed the requirements for the permissible values of the main relative error, as a rule, in the range of minimum gas flow rates. Ways to increase the service life of gas meters are proposed.

Keywords: gas flow metering, gas meter, verification, basic relative error, gas flow

The article provides the definition of a deep pit. The authors substantiated the need for fixing the walls of excavations with a depth of 3-5 meters and the development of methodological recommendations and reference data for the selection of optimal methods and structures used for enclosing the excavation. Wooden sheet pile is the most affordable and technically simple solution for fixing the walls of excavations with a depth of 3-5 meters. The authors calculated the structural characteristics of a wooden sheet pile for various soil conditions according to the method proposed by Professor E.K. Jacobi. The results are presented in a reference table, a fragment of which is given in the article. The developed reference data make it possible to assess the feasibility of using a wooden sheet pile without additional calculations. Engineers can determine the required cross-sections of the fence and struts, the immersion depth of the wooden sheet pile, the step of installing the struts according to the reference data.

Keywords: deep pit, fixing the walls of the pit, sheet pile, E.C. Jacobi method, pit collapse, pit slopes, earthworks, work safety, wooden sheet pile, accident