The lack of clear recommendations in the regulatory and scientific literature on laying a heating network in an impassable channel not only increases the construction time, but also leads to serious design errors, which entail a decrease in the service life of the engineering network and the occurrence of emergencies at the facility. In this article, a methodology for a numerical experiment of laying a heating network in an impassable channel was developed, an experiment was planned with the choice of controlled factors. Data processing and analysis of the reliability of the results were carried out in order to simplify construction in urban conditions.

Keywords: channels of heating mains renovation, stressed-deformed state, methodology, numerical experiment, closed channel, experimental planning theory, finite element method, mathematical modeling, "black box"

The operability of an optical device depends entirely on the quality of the optical parts that make up the optical system. Timely measurement of errors of optical parts in the process of surface shaping organizes feedback: the more accurately the error is measured, the more accurately the correction of the geometry of the surface is possible. Errors of optical surfaces and optical systems in general can be estimated by the mismatch of coordinates of real and ideal (calculated) profile curves of surfaces; mismatch of normals to this surface; difference of wave fronts in incident and refracted (or reflected) beams of light rays, etc.. The reproducibility of optical surfaces from sample to sample and their compliance with the calculated one is usually estimated by the discrepancy between the actual and theoretical functions of the course of light rays. Such a discrepancy is estimated by the aberrograms of optical systems, which are determined experimentally on special installations – aberrographs. Unlike the known schemes for measuring longitudinal aberrations of only reflectors or only lenses, the devel-oped installation is universal, designed to measure zonal aberrations of large-diameter mirror and lens lenses that are used in lighting devices, solar energy concentrators, transmitting and receiving optical systems of optoelectronic de-vices.

Keywords: aberrometer, aberrogram, longitudinal aberration, lens lens, mirror lens

The paper presents the properties and nomenclature of products made of ceramic fiber used for insulating lining in steam reforming furnaces. On the example of the lining of the radiant chamber, the technology of mounting ceramic blankets on anchor studs, which is currently used in the construction and repair of reforming furnaces, is considered. The shortcomings of the existing technology are noted. These include the complexity of the process, the complexity of installation control and the high probability of uneven thermal conductivity of the lining surface due to hidden defects, as well as the spraying of ceramic fiber particles in the air that cause diseases. The nomenclature and technology of installation of insulating lining with ceramic blocks along guide tubes with subsequent resistance welding with the camera body is proposed. The technology will reduce the repair time, improve the thermal conductivity of the camera, reduce the risk of diseases.

Keywords: gas reforming, radiant chamber, insulation lining, ceramic fiber, thermal conductivity of the furnace

Pipe fittings, which are one of the main elements of any type of pipeline networks, can be used for various purposes: shut-off, reverse, safety, control, separating, shutting off, etc. In order to control the performance of this element, it is necessary to carry out various tests in the prescribed manner, the main ones being pneumatic. This study is devoted to the development of equipment for in-plant pneumatic testing of rotary check valves for pipeline systems of hazardous production facilities with ultra-high parameters of the working environment. For this design of the installation, the simulation of the stress-strain state of the elements of the installation was carried out, as well as the gas-dynamic calculation of the test circuit of the installation.

Keywords: rotary check valve, pipeline fittings, pipeline system, mathematical modeling, finite element method, strength analysis, stress-strain state, computational fluid dynamics, pneumatic testing, technological pneumatic installation

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

Location of compensating devices is determined by various factors: configuration of power supply system, enterprise load schedule, type and length of power lines, parameters of capacitor banks, value of supply voltage. We consider the influence of the above factors on the creation of a mathematical model to determine the location of compensating devices, taking into account the minimum economic costs.

Keywords: compensating devices, reactive power compensation, power system, power grids of industrial enterprises, load schedule, mathematical model, reduced costs

Pipeline networks today are the main and one of the safest ways to transport all kinds of media. This engineering system consists of various elements, one of which is pipeline fittings that regulate the parameters of working media and protect pipelines from overpressure. In order to control the operability of pipeline fittings, it must be subjected to comprehensive tests, one of which is a leak test. The presented study describes the developed design of a technological hydraulic installation intended for use as part of process equipment for conducting in-plant testing of pipeline valves. The results of modeling the stress-strain states of the main units, as well as the hydraulic calculation of the test circuit of the installation are presented.

Keywords: rotary check valve, pipeline fittings, pipeline system, mathematical modeling, finite element method, strength analysis, stress-strain state, computational fluid dynamics, hydraulic tests, technological hydraulic installation

The main recommendations for the installation of a gas pollution detector in domestic premises are considered, an experiment is conducted using the Altair 4x gas analyzer, the purpose of which is to determine the concentration of the gas-air mixture at various points of the household relative gas source. The data obtained experimentally is analyzed, which results in a formula that allows you to determine the approximate concentration of the gas-air mixture, I only know the measurement time and height relative to the ceiling to the measurement point. Also, this formula allows us to note that when choosing the installation location of the gas pollution detector, attention should be paid to the distance from the ceiling to the installation point of the device, while the distance from the wall to the installation site of the device plays a less important role when a gas leak is detected by the device.

Keywords: gas pollution detector, gas-air mixture, gas concentration, emergency shutdown, lower concentration limit of flame propagation

The article discusses methods and models for evaluating options for design solutions for the installation of special-purpose structures when solving problems of construction and technical expertise, and also describes a catalog of design solutions for the installation of special structures, including information on cost, resource, time characteristics and possible technological methods, mechanization tools used materials, the need for transport, the necessary quantitative and qualitative composition of brigades and links of workers.

Keywords: construction and technical expertise; design solutions; installation of special facilities; construction expert; multi-criteria assessment; organizational and technological solutions

The study evaluated the effect of the spring position in the panel on the amount of force required for vertical pushing of the columns. The results show that the farther the spring is from the hinge, the less pushing force is required to lift the column. In this method, the column was connected to the panel by hinged hinges at the factory, which allows lifting elements by crane as a single group during the installation of the frame structure on the construction site. In addition, a spring is installed on the panel at a certain distance, helping to push out the column and secure it. In this article, a threaded connection of precast reinforced concrete columns is proposed, which can be used to connect elements of fully assembled buildings and structures. The contact-screw connection of precast reinforced concrete consists of an upper and lower column, both have a cylindrical steel external thread in the end section connected. The strength of the screw column connection is determined by ensuring the transmission of axial loads and torque in the joints, ensuring the destruction caused by cutting and thread confusion that may occur between the connected columns. By means of the necessary calculations for the screw connection of columns made of precast reinforced concrete the corresponding rigidity and strength were confirmed. The new connections will contribute to the development of construction, its energy efficiency and acceleration of the installation process. These are effective approaches to reducing effort, time, and labor and energy costs.

Keywords: prefabricated buildings, passive assembly, column connection, screw connection, energy efficiency of installation, mounting spring, hinge loop

The article discusses the principles of design and arrangement of foundations using soil-lime pads on subsiding soils in special natural and climatic conditions of the Republic of Tajikistan. Recommendations for the design of bases and foundations for civil buildings for the territory of the republic have been studied and proposed.

Keywords: bases, foundation, subsiding soil, buildings, structures, soil-lime pad, foundation pit, seals, strength, density, pressure

The article is devoted to the design and specifics of the operation of an LED variable irradiation installation for growing plants. The peculiarity of the proposed installation is the periodically changing intensity of irradiation, achieved by alternately switching on and off LED radiation sources. This approach allows you to reduce the power of the power source, which leads to a reduction in the cost of the installation design, improve the quality of the products obtained, thanks to uniform irradiation of plants and reduce the energy intensity of the growing process.

Keywords: led installation, irradiation installation, energy saving, variable irradiation, control unit, microcontroller

The article considers the possibility of optimizing the composition of the reinforcement link when installing the reinforcement frame of vertical monolithic structures. Various variants of the composition of the reinforcement link are considered, depending on the options for connecting reinforcement rods in vertical monolithic structures (binding of the reinforcement frame with a knitting hook, with an automated gun and with a coupling connection). The data for the calculation were obtained by the method of timekeeping of the reinforcement works considered in the article. Based on the conducted timekeeping and the construction of a mathematical model, the optimal composition of rebar workers was determined when performing reinforcement work.

Keywords: timing, mathematical model, optimization, connection of reinforcing bars, link composition, reinforcing bars, monolithic structures, dependency graph, labor intensity, minimum numerical composition of the link, qualification composition of the link

The article offers an environmentally friendly method to assemble pipes into section in order to build, to reconstruct or to fully repair pipelines both in urban communities and outside them eliminating load-carrying devices. The technique is realized with a specially designed assembly line (DAL) consisting of similar devices positioned along one line. The proposed assembly line is executed as multi-functional since the complete range of production processes can be performed with it, starting from unloading pipe sections to laying a ready section into a trench or onto an elevated pipe pier. The offered engineering solution can be used in all places. 3-D spatial models are presented in the article for illustrative purposes.

Keywords: environmentally friendly method, assembly works, pipeline, pipeline assembly, lifting equipment, engineering process

The article provides the information about the erection procedure of a 50.3 m span truss of a multifunctional sports complex in Nefteyugansk, Russia. The expediency of the considered large-span structure in finished form was substantiated by authors. The advantages and disadvantages of the options for choosing the erection procedure were analyzed in detail. Both types of finished truss erection were simulated in Autodesk Revit software: erection with one crawler crane and with two truck mobile cranes. The advantages and disadvantages of these two methods were observed. Erection process with two truck mobile cranes Liebherr LTM 1160-3.1 does not require complicated motions on the construction site, however it is imposiible with intalled beams between coloumns. For erection process with one crawler crane Liebherr LTM HS 855 HD temporary roads is not necessary, but this crane needs special transport for delivery on site.

Keywords: large-span structure, truss, erection in finished state, suspended cantilever method, jib crane, mobile crane, crawler crane, lifting equipment