The article proposes new compositions of a fast-hardening concrete mixture using Portland cement, fine and coarse aggregates, basalt fiber, a complex modifying additive including acetone-formaldehyde resins and magnesium chloride (bischofite). The results of scientific and experimental studies are presented and the influence of the proposed additives on the formation of the structure, rheological and physico-mechanical properties of fast-hardening concrete is determined. Analysis of the test results showed that the proposed formulations, including a complex additive and basalt fiber, contributed to a decrease in the water-cement ratio, increased mobility of the mixture and increased strength of hardened concrete in the early and final hardening periods.

Keywords: concretes, oil and gas storage, modifying additives, fiber, mobility, setting time, strength

The article discusses the features of pipeline construction in permafrost conditions. Classical technical methods of design and construction are economically unprofitable. It is necessary to introduce new design solutions that can significantly reduce the anthropogenic impact of the pipeline on permafrost soil with a minimum of construction and subsequent operation costs.

Keywords: pipelines, permafrost, special supports, thermal insulation of the pipeline, thermal stabilization

The article presents the results of a study of the mechanism of occurrence of cracks in the material of heated cylindrical porous powder blanks being deposited. The type of cracks is classified and the role of the boundaries between the "particles" of powder on the surface of a porous workpiece as stress concentrators contributing to the formation of cracks during its deformation is noted.

Keywords: dynamic hot pressing, heating temperature, powder billet, pore, crack, sintering temperature, plasticity

The problems of modern methods of building construction, namely the obsolescence of construction technologies and the production control system at most facilities under construction do not provide the required level of quality. Due to low-quality materials, formwork, reinforcement, laying and ramming, defects and deviations from the most important requirements for the finished product appear and resource costs increase significantly. Therefore, in order to develop and introduce effective measures to improve the existing methods of building construction, this paper lists the main disadvantages of the technologies used. The practice of applied innovative technologies that can increase the quality and speed of the structures being built is given. The technologies of erecting buildings using various fixed formwork designs are considered.

Keywords: sound insulation, shock noise, residential buildings, noise insulation, air noise, monolithic house, comfortable environment, noise, construction, materials

As the number of low-orbit satellite constellations (LEOs) increases, the probability of destructive impact from alien spacecraft (SC) will increase. One of the most effective impacts on the NHS is the setting of relay interference, which is an intercepted and delayed signal. This problem can be eliminated by using the "friend or foe" identification system for the spacecraft. At the same time, in order to reduce the probability of selecting the correct transponder signal by a foreign spacecraft, it is proposed to reduce the time spent on calculating the status of the satellite through the use of parallel calculations using codes of the polynomial residue number system (PRNS). A characteristic feature of these codes is the independent and parallel execution of calculations based on the bases of the PRNS. However, this property of the PRNS code can also be used to correct errors that occur during the operation of the identification system. In this case, the algorithm must perform this procedure at a lower time cost. Therefore, the modification of the error correction algorithm, which makes it possible to provide a higher speed of searching and correcting errors, is an urgent task. The purpose of the work is to reduce the time spent on the execution of the procedure for detecting and correcting errors during the operation of the identification system, by modifying the correction algorithm based on the Chinese residual theorem

Keywords: satellite identification system, codes of the polynomial residue number system, positional characteristic, error detection and correction algorithms

The problem of choosing the most optimal gas supply scheme for rural settlements is considered, taking into account technical and economic criteria. For example x. Knyazhensky-1, Mikhailovsky district of the Volgograd region, several gas supply schemes are proposed. The feasibility study of the choice of one of the possible options is given. It was found that for rural settlements with an extended form, the most optimal is a scheme with two sources of gas supply and a reserving jumper between them.

Keywords: gas distribution network, gas reduction points, hydraulic regime, normalized pressure, cost, construction and installation works

The article presents the results of studies on the influence of sintering modes on the distribution of carbon in the material of a porous powder billet used for the manufacture of a differential satellite by dynamic hot pressing. The distribution of carbon and density in the satellite material is established, recommendations for its chemical and thermal treatment are given.

Keywords: dynamic hot pressing, heating temperature, powder billet, density, satellite, sintering temperature, cementation, quenching, material property

The problem of removal of combustion products during the reconstruction of existing boiler houses is considered. The issue of determining pressure losses due to friction in steel and brick gas ducts when performing an aerodynamic calculation of gas ducts from gas-fired boilers is considered. Nomograms have been developed that make it possible to determine the specific pressure loss depending on the volume of flue gases and the diameter of the gas ducts.

Keywords: reconstruction, boiler units, aerodynamic calculation, friction pressure losses, gas ducts

The problems of modern monolithic construction, namely errors in the installation of sound insulation in monolithic construction, require special attention, since the increased level of noise and vibrations during the operation of premises affects the psychophysical state of a person. Modern enclosing structures are often used in standard solutions without the necessary additional sound insulation. Therefore, in order to develop and introduce effective measures to prevent existing defects in the premises, this paper lists the main factors affecting the high level of permissible noise in the premises. The practice of applied methods and solutions used to improve the sound insulation of individual structures is given. The technology of performing works on the device of sound and noise insulation in residential premises, with an indication of the maximum permissible noise level, is considered.

Keywords: sound insulation, shock noise, residential buildings, noise insulation, air noise, monolithic house, comfortable environment, noise, construction, materials

This article discusses the advantages and perspective for the use of biogas in the conditions of the Republic of Crimea. The ecological and economic aspects of the use of biogas technologies at winemaking enterprises are touched upon. Describes the methods of using biogas at the winery "Massandra" in the Republic of Crimea. The calculation of the use of natural gas in the boiler house of a winery is made. A calculation was made for the use of biogas in a boiler house. It can be concluded that when using biogas in the boiler house of a winery, fuel needs are fully covered. The surplus of the remaining fuel is proposed to be used in a cogeneration plant to generate electricity.

Keywords: biogas, cogeneration plant, grape plant residue, recycling, interchangeability, granulate, natural gas, grapes, thermal energy, electricity, winery

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