The article addresses the issue of determining the ultimate eccentric compressive longitudinal force from an external load acting on a compressed reinforced concrete element. The calculation assumptions are adopted in accordance with the current code of practice SP 63.13330.2018. The transformation of the initial formulas given in this code allowed the explicit solution of the cubic equation with respect to the compressive longitudinal force without the need for iterative calculation methods. The solution thus obtained can be employed in the design process to determine the optimal section dimensions.

Keywords: reinforced concrete, excentric compression,ultimate forces

The oil and gas engineering industry is undergoing changes that are associated with the introduction of innovative technologies, methods and tools to improve production processes and systems. All changes make it possible to achieve an increase in the average resource, durability and profit of the enterprise as a whole. Processing parts of the oil and gas complex and reducing all types of wear on the cutting part of the tool currently remains the most pressing topic. The continuous operation of a cutting tool is influenced by many factors. The relationship between cutting speed and tool life allows you to select the optimal speed. The work identifies the main directions of research on the selection of wear-resistant coatings for cutters to improve the accuracy of metalworking. The research was carried out using modern computer programs, which made it possible to draw certain conclusions, derive dependencies and determine the range of tasks for further research. Application of the main results will improve the processing efficiency and surface quality of parts in the oil and gas sector.

Keywords: durability, cutting mode, cutter, optimization, experiment, methodology, accuracy, processing, coatings, deformation

The safety of hazardous production facilities is directly related to the reliable operation of pipeline systems, as a failure occurring in the elements of such systems can lead to serious consequences for production facilities and the environment. Since the greatest number of failures is associated with faults caused by corrosion, to increase reliability it is necessary to increase the corrosion resistance of metal of pipeline elements. The article gives an overview of materials for manufacturing parts, the influence of different climatic conditions on the mechanical properties of steels. The developed rotary gate designed for automatic prevention of reverse flow of working medium is also presented. To confirm the serviceability of the design, strength calculation of the structure was carried out, where its stress-strain state under the given loading conditions is considered. As a result, the values of maximum equivalent stresses, maximum deformations and displacements were obtained, which are lower than the maximum permissible ones.

Keywords: pipeline system, pipeline, shut-off valves, swing back gate, mathematical modelling, finite element method

A review of the literature in the field of construction heat engineering and regulatory requirements for thermal protection of buildings is given. A study of methods of increasing thermal protection for reconstructed and designed buildings, taking into account modern requirements, has been carried out. A methodology for strengthening the thermal protection of building structures has been developed.

Keywords: thermal performance of building , energy efficiency, heat-efficient enclosing structures, thermal insulation materials

The main characteristics of the building for dynamic calculation are the frequency and forms of natural oscillations. These values are related to the rigidity of the building, the rigidity of the elastic foundation and its mass. To study the effect of the stiffness of the elastic foundation, an equivalent idealized model of free oscillations of a cantilever rod is considered. The calculation takes into account the rigidity of the support. For the considered model, a transcendental equation and its numerical solution is obtained. Solutions for the limiting cases of elastic foundation stiffness are obtained. The obtained results allow us to analyze the effect of the stiffness of the elastic foundation on the frequencies of natural oscillations. It is calculated that with an increase in the stiffness of the elastic foundation, the frequencies of natural oscillations increase. The influence is limited and has an asymptotic character. The rigidity of the elastic foundation can have a significant effect on the natural frequencies of the first five bending forms of natural oscillations and may not be taken into account for higher-order forms.

Keywords: dynamics, natural oscillations, natural frequencies, building, structure, transcendental equation, elastic foundation, elastic support

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

A methodology has been developed that can be used to develop calculation and instrumental methods for determining the standards for the accumulation of solid municipal waste for retail chains under common management, having a single trade and technological process, a similar range of goods for sale and carrying out separate accumulation of secondary material resources.

Keywords: accumulation of waste, municipal solid waste, generation standard, object of a stationary trading network, cluster analysis

The reliability of assessing the amount of accumulated waste in the context of an imperfect scientific and methodological base for standardizing MSW, in the absence of generally accepted calculation methods, is not high enough. The possibility of using cluster analysis in the formation of a statistical sample of objects of a stationary trade network in setting standards for the accumulation of municipal solid waste is shown. A methodology for the formation of a representative statistical sample of objects of a stationary trading network has been developed when setting standards for the accumulation of solid municipal waste based on cluster analysis.

Keywords: waste accumulation, municipal solid waste, MSW generation standard, stationary trade network object, cluster analysis, representative sample

The wastewater generated by the pulp and paper industry contains diverse contaminants such as organic substances, fine suspended powders, and dissolved solids. Currently, integrated treatment technologies are employed, utilizing thin-layer settling tank modules to eliminate solid contaminants. This study presents the outcomes of a comparative analysis of the efficacy of a conventional thin-layer module with flat plates and a modified thin-layer module consisting of two levels of plates, positioned in opposing directions, facilitating the rotation of water flow within the module. Through computer simulation techniques, it is demonstrated that the modified module design can enhance the cleaning efficiency by 8-30% for wastewater flow velocities ranging from 0.0025 to 0.0125 m/s. Additionally, particle trajectories and velocity fields were obtained, which clearly illustrate the direction of the dictating flow and circulation zones within the structure.

Keywords: Wastewater, pulp and paper industry, thin-layer module, module with rotation of water flow, computer simulation of particle deposition.

The design of energy-efficient buildings is based on the analysis of the external climatic effects on buildings for various purposes, the parameters of the air environment inside which are well defined. Climate systems of buildings should neutralize the negative impact of the external environment, in particular wind exposure. It determines both the temperature regime of the room and the purity of the air inside them. The complexity of both theoretical research and the organization of field experiments or blowing models of buildings in a wind tunnel makes it necessary to resort to mathematical modeling of the wind impact on the school building based on the StarCCm+ program. Velocity fields were obtained for different directions of wind load, the excess heat loss of the building in certain directions was determined. The possibility of conducting such studies in a wider range of initial and boundary conditions is shown.

Keywords: aeration of residential buildings, mathematical modeling

Bottom sediments (UP to) are media in which both longitudinal and shear acoustic vibrations can be present. The presence of several velocity components in bottom sediments makes it possible to excite various types of waves, both longitudinal and shear. In this paper, methods of excitation, generation and reception of difference frequency shear waves (RF) created by parametric systems in (DO) in location modes are analyzed. The analysis of their work in the DO is presented, and their comparative characteristics are given in comparison with the excitation, formation and propagation of the field of longitudinal RFCs in the DO. Prerequisites are given for the creation of a parametric profiler working using the method of excitation, generation and location of shear waves in a complex multiphase medium ""water-DO"". A block diagram is presented and the principle of operation of a parametric profiler on shear waves is described. The advantages and disadvantages of this method of location are shown. The conclusion is made about the possibility of creating and ration.

Keywords: parametric antenna, bottom sediments, shear waves, difference frequency waves, parametric profilogaf

The testing of technique for modeling the local atomic structure and X-ray absorption spectra for zinc ions in an aqueous solution in the presence of arachidic acid has been adjusted. Models of the local structure of zinc with different coordination geometries are considered: planar, pyramidal, tetrahedral, and octahedral. The cases of increasing distances between the zinc ion and water molecules in the plane and in the axial direction are simulated for octahedral coordination. It has been established that the most probable change in the local structure of the zinc environment in solution in the presence of arachidic acid is the removal of water molecules from zinc ions in the axial position and their further replacement with the formation of a bond with the carboxyl group of arachidic acid.

Keywords: arachidic acid, lipid layer, local atomic structure, X-ray absorption spectroscopy, total external reflection, zinc, biomembrane, finite difference method, monolayer

The article is devoted to the control system for the process of moving textile material in an apparatus for impregnating fabrics with periodic action. The control is implemented using a programmable logic controller (PLC). We consider a program developed in the Ladder Diagram (LD) programming language that implements motion control taking into account the change in torque.

Keywords: solution, immersion, technological process, algorithm, programming language LD

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 issues of ensuring the reliable operation of bearing production on the basis of the organization of the process monitoring system (SMTP), based on the introduction of effective automated control and diagnostics of technological equipment, including processing modes and technical condition, active control of product quality in the manufacturing process, output characteristics of rings processed by the eddy current method, as well as making decisions on timely maintenance of equipment. The results of the inspection are stored in a report file generated in the eddy current device computer: information about each checked part is stored: the time of inspection, the type of part, the surface to be monitored, the number of the machine on which the part was processed. The results of eddy current control serve as the basis for monitoring the dynamic characteristics of the equipment by vibroacoustic vibrations. Based on the results of the control within the framework of the SMTP, a decision is made on the quality management of processing. The introduction of SMTP provided a significant reduction in ring defects in terms of grinding quality up to 2-3 % and increased operational reliability of bearings.

Keywords: grinding process monitoring, bearing rings, dynamic machine quality, active control, eddy current control, ring quality