Expert work has been carried out to establish quality indicators for three types of concrete paving slabs: "Auriko", "Paving stone", "New City". The tests were carried out on selected samples in accordance with GOST 17608-2017. According to the test results, it was determined that only the samples of "Paving stones" tiles meet the requirements of GOST, other types of tiles revealed non-compliance of the studied samples with GOST 17608 in terms of water absorption and frost resistance.Frost resistance tests for Aurico and Novy Gorod product samples were interrupted after 15 freeze-thaw cycles due to the destruction of the samples.

Keywords: paving slabs, concrete, compressive strength, frost resistance, surface defect "sink"

To develop a methodology for assessing the strength of ring flanges, research was conducted on the load-bearing capacity of welded pipe joints of varying diameters. The study employed the component finite element method (CFEM) implemented in the IDEAStatiCa Connection software. To verify the obtained results, a numerical experiment was carried out using the ANSYS software package. The investigation considered several types of flange joints made from welded pipes with different diameters. Parameters were selected based on common sections used according to russian Series 3.400-8 (Issue 2). The study found that for all cases, the highest stresses occurred on the flange at the joint with the smaller diameter pipe. The analysis indicated that the CFEM's applicability should be limited to diameter-to-wall-thickness ratios (D1/t1) of up to 40. Beyond this threshold, the CFEM does not accurately predict the strength of the joints due to the significant deformation that occurs in the pipe walls, forming a truncated cone shape at the flange junctions. For practical applications, formulas are proposed to check the strength of ring flanges. These formulas account for the weakening of the plates by bolt holes and provide conservative results. The findings highlight the necessity for additional numerical and physical experiments to refine the methodology for cases with D1/t1 ratios exceeding 75. The proposed approach offers a practical solution for evaluating the strength of ring flanges in welded pipe joints of varying diameters, contributing to the development of relevant engineering standards.

Keywords: load-bearing capacity, ring flanges, welded pipes, assembly joints, strength, component method, numerical experiment

Framed fabric roof structures of the sawtooth-type are considered. The structures are arranged on rectangular plan. They consist of a number of sectors which are separated by arch-shaped supporting ribs. The sectors are covered with a prestressed soft shell. Geometric nonlinear static analysis of the shell is performed taking into account the effect of snow and wind loads. The general dimensions of the shell and the prestress value are considered as the primary variables. Quantitative assessment of deformation of the shell is carried out by means of so-called deformability index. The index is reciprocal to the relative deflection. A functional expression for approximating the deformability index is proposed. The expression is to be used at the stage of developing the design solutions for fabric structures. The coefficients of the function are found by means of the least squares method. The guidance for assigning the main parameters of the sawtooth-type fabric structures are given.

Keywords: fabric structure, roof structure, soft shell, sawtooth roof, geometric parameters, prestress, deformability, approximation

Stepper motors are often used in automated laser cutting systems. The control circuit of a stepper motor requires a special electronic device - a driver, which receives logical signals as input and changes the current in the motor windings to provide motion parameters. This research study evaluated stepper motor drivers to determine the feasibility of their use - PLDS880, OSM-42RA, OSM-88RA. To control the system, software code was written, which was connected to the controller via a link board. With each driver, in different modes, optimal parameters were selected (initial speed, final speed and acceleration), that is, the movement of the carriage without stalling for ten passes with a minimum travel time. The results of the experiments are presented in the form of tables.

Keywords: laser, laser cutting, automation, technological process, stepper motor, performance, driver, controller, control circuit, optimal parameters

The article considers the solution of the urgent problem of calculating the size of the effective focal spot of a microfocus X-ray tube using computer modeling methods. The principle of operation of the calculation method used by the authors is to compare interference images obtained using tested microfocus X-ray tubes with simulated interference patterns formed using the developed software by numerically solving the wave equation. It should be noted that modeling a one-dimensional interference pattern using fast Fourier transform requires a significant amount of RAM and takes considerable time even when using modern computer equipment. The paper presents the results of modeling phase contrast profiles for two types of test objects – nylon fishing line and aluminum wire. The considered method for determining the size of the focal spot is characterized by good sensitivity and allows efficient and high-precision calculations for all types of microfocus X-ray tubes.

Keywords: computer modeling, X-ray tube, microfocus source, focal spot, non-destructive testing

The article analyzes modern approaches and technologies for recycling and recycling of building materials. Such types of waste as reinforced concrete, brick, glass, wood, plastic, etc. are considered. Special attention is paid to innovative methods of processing to obtain secondary raw materials (recycling). It is shown that the most promising technologies are the crushing of concrete, brick and reinforced concrete for reuse in construction, the melting of scrap metal, glass and plastic, the processing of wood waste into slabs and fuel. There is an insufficient level of application of innovative solutions in Russia. A set of measures has been proposed to improve the efficiency of construction waste disposal: the introduction of advanced technologies, the construction of waste recycling plants, the adoption of a targeted state program, and the improvement of environmental culture.

Keywords: waste, construction debris, Russia, secondary raw materials, reuse, environment, recycling, burial, recycling

The article contains the methodology and results of theoretical and experimental studies of the stress-strain state of a conical radial-beam dome with triangular shell elements. The results obtained by various methods are analyzed and compared. The triangular membrane panel is part of the radial beam dome structure and consists of a support frame and a steel membrane in the shape of a triangle. The shape of the triangle forming the membrane panel can be different and depends on the number of ribs in the radial beam dome. The supporting contour is a compressed-bending element of the dome and is made, as a rule, from a rolled steel profile with a channel section. The membrane is made of thin steel sheet and attached to the upper flange of the channel with self-tapping screws or spot welding. To assess the strength and deformability of a steel membrane sheet, its operation under the action of a uniformly distributed snow load, an unevenly distributed snow load and a concentrated installation load was considered. Several options for nonlinear static calculations in various computer systems are shown.

Keywords: building structures, wooden structures, membrane panel, stress-strain state, radial beam dome, dome, membrane, design, experimental study

Bar structures are widespread in construction due to their economy, freedom of design shapes and sizes. As a result, automation of design and calculation of such structures is an urgent task. As part of the study, the task of developing a software module that generates a map of optimal cutting of rolled metal based on the results of calculations of rod structures has been implemented. The algorithm under consideration takes into account such features of the cutting optimization problem as taking into account the width of the blade, the possibility of using half the size of the rolled product, support for optimization of several sections, and welding of parts in case the length of the workpiece is exceeded. The software module is developed using JavaScript and C# languages. The ability to automatically generate cutting maps based on the results of optimization of rod structures increases the efficiency of designing building structures.

Keywords: Design in construction, bar structure, computing system, web development, design in construction, rod structure, computer system, web development, optimal cutting, rolled metal, cutting map

The article is devoted to the use of reinforced soils in the base of pavements of highways located in the I road-climatic zone. The features of the operating modes of reinforced foundation soils are considered, and their physical and mechanical characteristics with various combinations of mineral and polymer modifiers are determined. The authors analyze the advantages and disadvantages of using reinforced soils. The article also discusses the design and construction of roads using reinforced soils.

Keywords: highway, road pavement, foundation, soils, reinforced soils, modifiers

This article presents the results of theoretical research in the field of methods for determining the forces arising in the traction return ropes of the balloon system used in transport, cargo and construction works. The emphasis is placed on the accuracy of the swivel positioning when exposed to a wind flow on the balloon. Theoretical calculations of the main parameters are given, such as: high-speed head, resultant lifting force, rope span, rope force, rope deflection, swivel movement and others. A technique is proposed that allows for a relatively simple and rapid calculation of rope forces in the process of performing cargo operations by an aerostat crane on a construction and installation site.

Keywords: balloon system, balloon crane, traction and return ropes, rope forces, drag, aerial construction and installation work, swivel

The article discusses standard models of titanium dioxide-based memristors. A memristor is similar to a memory resistor and demonstrates a nonlinear resistance characteristic in which the charge parameter is a state variable. They can be used to create new types of electronic devices with high energy efficiency and performance, as well as to create machines that can learn and adapt to changing environmental conditions and in many practical applications: data storage memory (binary and multilevel), switches in logical electronic circuits, plastic components in neuromorphic artificial systems intelligence based on nanoelectronic components. It has been shown that when voltage is applied to charged ions, they begin to drift, and the boundary between the two regions shifts. When a sinusoidal alternating voltage of a given frequency is applied to the memristor, the shape of the volt-ampere characteristic (VAC) resembles a Lissajous diagram centered at the origin.

Keywords: memristor, model, voltage characteristic, nonlinearity

The article shows the importance of the role of clinical engineering departments in ensuring high-quality comprehensive control of the state of medical equipment at all stages of its life cycle. The main resource of such departments is the resource of working time of clinical engineers. In order to rationalize the use of this resource, we analyzed data on the time budget for the maintenance of 2459 units of medical equipment in medical institutions of Volgograd. The results of the analysis allowed us to identify 3 subgroups of medical equipment in the general data array that have statistically significant differences in the time characteristics of their maintenance and require a different approach to managing the time of clinical engineers servicing them. At the final stage of this study, ABC-XYZ analysis was used. Its results allowed us to formulate recommendations for rationalizing the use of working time of clinical engineers to work with the subgroups of medical equipment identified in this study in practical conditions.

Keywords: clinical engineering, clinical engineer, time budget, maintenance of medical equipment

Technology of jet-grouting is a method of strengthening weak or heavily watered soils by pumping high-pressure cement slurry into the well to break the structure of the soil and simultaneously stirring its particles with cement slurry. The result is a ground-cement mass which has predefined improved strength and deformation characteristics. Technology of jet-grouting has a great potential for development and application in various construction industries, such as buildings, roads, bridges and other structures under various geological conditions. The development of jet-grouting technology won't only expand its application, but can improve competitiveness in the construction services market.

Keywords: recycling, reinforced concrete, secondary crushed stone, construction waste, crushing equipment.

The article discusses the use of organic binders to modify the properties of cement soils. The scope of application of cement soils in construction practice, including the construction of highways, is considered. The influence of the use of organic binders as a complex additive that modifies the strength characteristics of cement soils has been studied. The influence of the use of complex modifiers and additives on the frost resistance and water permeability of cement soils has been determined.

Keywords: cement soil, organic binder, highway, working layer, frost resistance, modifiers

The article deals with the peculiarities of the results of tests carried out to determine the characteristics of the contact zone organized by stamping on a steel plate. During the test, the specimen was in the steel mold in which it was manufactured. The steel form was used to prohibit horizontal movement of the steel thin plates and minimize the effect of uneven slippage of the steel gouge in the direction perpendicular to the shear force. The considered tests were carried out according to a specially developed methodology, which took into account the specifics of the contact zone shear operation, the applied tooling and took into account the set objectives of the study.

Keywords: contact zone, contact characteristics, test methodology, shear tests, stamping, composite design