The article deals with the influence of complex mineral additive "chemical water treatment sludge + flask or fly ash" on the frost resistance of building mortars depending on the redispersible polymer powder dosage from 0 to 3%. According to the results of research after 100 freeze-thaw cycles, the condition RF/R0 > 1.2 is met, and the k value according to clause 5.2.4 of GOST 10060-2012 after 100–125 freeze-thaw cycles ranged from 0.94 to 1.73, the minimum value of the relative modulus of elasticity EF/E0 = 0.97, and the residual expansion deformation did not exceed 0.03%. Building mortars with fly ash have higher frost resistance according to the bending strength criterion in comparison with mortars with flask. The frost resistance criterion for bending strength is more “strict” than the criteria according to GOST 10060-2012. It is not advisable to use a dosage of RPP greater than 2% for the production of building solutions with increased frost resistance requirements.

Keywords: frost resistance of building mortars, frost resistance criteria, redispersible polymer powders, compressive and flexural strength, elastic modulus, permanent expansion deformation

The article shows the importance of analyzing the state of strength properties of old wood during restoration work and monitoring the state of the structure. In particular, the physical and mechanical properties of wood during long-term use in an aquatic environment are analyzed. Changes in the chemical composition of wood as a result of use in the water of the Gulf of Finland are determined. Using the example of logs of the crib foundation of the Kronshlot fort, it is described how a change in the chemical composition of the material affects its strength properties.

Keywords: Mechanical properties of wood, long-term strength, chemical composition of wood, water-soluble extractive substances

Since 2017, EVRAZ ZSMK JSC has been developing and operating a mathematical model covering all processing stages from ore extraction to final products – SMM Forecast. The model will be used to calculate technical cases, plans, and parity prices for iron ore and coal, and its use brought more than 200 million rubles of economic effect in 2020 alone. The use of a universal mathematical model made it possible in 2023 to begin the development of a module for daily optimization of an agglomeration factory and blast furnace production. The article discusses the experience of EVRAZ ZSMK JSC in the development and implementation of a daily planning system based on the monthly planning model of SMM Forecast, as well as methods for achieving an acceptable speed of multi-period optimization. The SMM Forecast system was originally designed for end-to-end, scenario-based calculation of the main raw materials from ore and coal to finished products in a volumetric monthly planning. The system uses optimization algorithms to search for a global target function to maximize margin income under specified constraints. The mathematical model of redistribution uses the norms and technologies specified in the company's regulatory documents. At the same time, the model is universal and the transfer of algorithms from monthly to daily mode was carried out with minimal modifications. The article also discusses the difficulties encountered and various methods of solving these problems. The first problem faced by the developers was the low speed of optimization of the model in daily dynamics due to the strong complication of the optimization load. The calculation time has increased significantly, and to solve this problem, it took the introduction of a number of optimization cycles aimed at reducing the speed of solving equations, introducing variable boundaries, and determining starting points. As a result, the calculation time for one month was about 40 minutes. The second problem was the need to develop a complex supply management algorithm and optimize stacking at the sinter plant. As a result of solving this problem, a working tool has been developed that brings additional income to the enterprise.

Keywords: metallurgy, modeling, planning, daily planning, sintering plant, blast furnace shop, stacking

The production of ultra high molecular weight polyethylene (UHMWPE) is associated with significant dust emissions into the production room, so the aspiration system plays an important role in the technological process. The study of dust in industrial product waste released into the work area is one of the objectives of the ongoing research. This work provides information on the dispersed composition of ultra-high molecular weight polyethylene (UHMWPE) particles, and various graphs are constructed based on the data obtained. Data on the deposition rate of UHMWPE particles were obtained experimentally. A comparative analysis of the obtained data with theoretical data obtained using formulas was carried out.

Keywords: ultra high molecular weight polyethylene, UHMWPE, dispersed composition of ultra high molecular weight polyethylene, sedimentation rate of ultra high molecular weight polyethylene particles, method for studying the properties of raw high molecular weight

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"

The paper discusses the use of carbon fiber composite materials for reinforcement of specimens made of pipe sections in tension under the action of internal pressure. Experimental investigations of steel pipes under the action of internal pressure both without reinforcement and with different number of reinforcement layers with carbon tape are described. The main interest is in the joint operation of the pipe wall and external reinforcement elements. Significant influence of external reinforcement on stiffness and deformability of the specimens is noted.

Keywords: high-strength fiber, carbon fiber, carbon tape, adhesion layer, pipe, external reinforcement system, polymer composites, tensile strength

The public education project ""Dream School"", implemented in support of the federal school overhaul program, attracts students of architectural and design schools in the regions, which will allow them to simultaneously acquire applied competencies in the learning process. During the development of the design project, the need for specialists to conduct a preliminary design analysis was revealed, since one of the five schools did not meet the standards in terms of their spatial planning parameters. It is proposed to carry out the reconstruction of this educational institution. The premises of the dining room and the assembly hall are transferred to the annex block.

Keywords: school design project, school renovation, school recreation, public education project "Dream School", school reconstruction

The article deals with the results of research on the influence of the dosage and composition of the complex mineral additive containing chemical water treatment sludge with gaize, burnt rock or fly ash. The result of investigation is the equation for the change in shrinkage deformations over the time for mortars containing a complex mineral additive in comparison with a standard mixture without additives. There is evaluating of the influence of changes in the mortar moisture on the amount of shrinkage deformation. On the base of the research, we astablished the dependences of shrinkage deformations on the moisture content of the mortar, according to the composition and dosage of the complex mineral additive. The study revaels the influence of a complex mineral additive on shrinkage deformations. The equation has been obtained that describes the change in shrinkage deformations depending on the relative humidity and it has been shown that the tested mortars with a rational composition and dosage of a complex mineral additive with an average air humidity of the driest month in Rostov-on-Don of 47% will not exceed 0.55 mm/m . Shrinkage deformation with the ratio of the complex additive with fly ash or burnt rock 20-30% are 0.42-0.79 relative to the additive-free standard.

Keywords: dry construction mixture, shrinkage, mineral additive, mortar, chemical water treatment sludge, burnt rock, fly ash

One of the directions that makes it possible to increase the efficiency of low-orbit satellite Internet in conditions of destructive influences is the use of OFDM systems that support the frequency hopping mode. It is obvious that the effectiveness of countering interference generated by electronic warfare (EW) is largely determined by the algorithm for selecting operating frequencies. In this paper, it is proposed to implement a block of SSF based on the SPN cipher "Grasshopper", which provides high resistance to the selection of the operating frequency by the SREB. However, in the event of failures and failures in the operation of such a unit, the transmitter and receiver operating in the microwave mode will not be able to establish information transmission. To solve this problem, the article proposes to use polynomial modular residue class codes (PMCCS). However, the analysis of the well-known error correction algorithms in PMCS has shown that they cannot be used to increase the reliability of the SPN-based CCF unit.

Keywords: Keywords: OFDM systems supporting frequency hopping, pseudorandom number generation methods, Grasshopper SPN cipher, polynomial modular residue class codes, error correction algorithm

This article provides a description of the developed hardware and software complex for controlling lamps using the DALI protocol, design features and software code, recommendations for operation.and development of new production on available floor spaces. The most important organizational economic targets of a diversification of management are presented by innovative activity of the industrial enterprise.

Keywords: DALI protocol, lighting device, lighting control, Arduino, luminous flux

The concept of digitalization of the construction organization project (POS) is presented, which is based on its close connection with the construction schedule. The place of the POS in the digital model of the building at the project stage (PIM) is considered. based on its digitalization, taking into account the relationship between information modeling at the project stage (PIM). The main problems that may arise when implementing the digital version of the POS in the general information model at the project stage are identified.

Keywords: BIM, TIM, POS, digital model, calendar schedule, construction organization

The work deals with the results of research on the influence of complex mineral additive: chemical water treatment sludge with burnt rock or fly ash or gaize. The rational content of chemical water treatment sludge in the complex additive was determined to be 50%. The relationship between compressive strength, flexural strength and W/C ratio, bettwen the flexural strength, E-modulus and the compressive strength were obtained. Complex mineral additive into fine grain concrete does not lead to a decrease in flexural strength and does not increase the E-modulus of fine grain concrete. The average range of the E-modulus of fine grain concrete with complex mineral additive practically coincide with those in Russian National Standart 56378 - 2015. The use of chemical water treatment sludge for fine grain concrete at amount of 20% of complex additive of a rateable composition instead of part of the cement provided to increasing of compressive strength at an equal W/C ratio relatively to the non-additive standard by 7 - 20%, and the flexural strength by 12 - 22% .

Keywords: miniral additive, tensile strength, modulus of elasticity, gaize, fly ash, burnt rock, chemical water treatment sludge

The article discusses the method of constructing a horizontal protective screen made of large-diameter steel pipes used for the construction of tunnel-type structures using a closed method. The factors influencing the choice of this method are analyzed - features of the construction site, economic and time indicators. As an example, a project for constructing a protective screen made of large-diameter pipes for the construction of a two-section transport tunnel under railway tracks is considered. Diagrams are provided that provide basic information about the construction project, its main parameters are considered: geometric shape and dimensions, location of structural elements with an indication of their sizes. The sequence of construction work is presented, consisting of six main stages, starting with the construction of auxiliary working pits and ending with the construction of the internal structures of the tunnel. Such construction of tunnels in dense urban areas requires taking into account and minimizing their impact on existing structures and transport routes in the construction area. The article presents the results of numerical calculations of stabilized movements of the soil mass, confirming the effectiveness of this method.

Keywords: horizontal protective screens, tunnel-type structures, large-diameter pipes, soil deformations

The problem of vulnerabilities in the Robot Operating System (ROS) operating system when implementing a multi-agent system based on the Turtlebot3 robot is considered. ROS provides powerful tools for communication and data exchange between various components of the system. However, when exchanging data between Turtlebot3 robots, vulnerabilities may arise that can be used by attackers for unauthorized access or attacks on the system. One of the possible vulnerabilities is the interception and substitution of data between robots. An attacker can intercept the data, change it and resend it, which can lead to unpredictable consequences. Another possible vulnerability is unauthorized access to the commands and control of Turtlebot3 robots, which can lead to loss of control over the system. To solve these vulnerabilities, methods of protection against possible security threats arising during the operation of these systems have been developed and presented.

Keywords: Robotic operating system (ROS), multi-agent system, system packages, encryption, SSL, TLS, authentication and authorization system, communication channel, access restriction, threat analysis, Turtlebot3

This paper examines the problems of optimizing the loading of client web applications and ways to solve them, taking into account various practical conditions. It provides ways to speed up the loading of web applications and remove blocking elements in the data processing chains in order to improve various aspects of the user experience. An approach is proposed that allows you to design an optimal application loading chain that meets the highest quality standards in the front end industry and provides the best user experience.

Keywords: front end, rendering, client web applications, load time, performance optimization, user experience