Based on the use of additional boundary conditions (characteristics) and the integral method of heat balance, a numerical and analytical solution of the heat conduction problem for an infinitely extended plate is obtained under symmetric boundary conditions of the third kind with constant internal heat sources in time. Considering the heat flux on the plate surface as a new sought function, a simple analytical form of the specified problem is obtained. Using the proposed approach is possible for solving partial differential equations that do not allow separation of variables.

Keywords: analytical solution, internal heat sources, non-stationary thermal conductivity, boundary value problem, boundary conditions of the third kind, additional function, integral of heat balance

The paving slab market analysis and development prospects for the Rostov Region are given in this article. The market prospects are considered from the point of view of paving slab manufacturers on their participation in government programs of a modern urban environment formation and improvement. The main changes in the product specifications requirements are considered taking into account the enactment of GOST 17608-2017 instead of GOST 17608-91. We analysed the pricing policy of large manufacturers of paving slabs operating in the Rostov Region. Then we also considered the prospects of paving slab sales for municipal projects and in the private segment. We also reviewed the government programs for creation of a comfortable urban environment and their financing in the Rostov Region, as well as cooperation prospects between the municipal government and business in terms of concession agreements. Finally, we defined the main consumer categories for the paving slabs and the consumption structure of the paving slabs market.

Keywords: paving flag, paving slabs, improvement, modern urban environment, the formation of a modern urban environment, paving

The simulation of a multilayer structure in the finite element Ansys complex is considered. The design consists of 10 layers, each of which has certain specific properties. The model is an imitation of the soil base pavement. We consider the simulation in the form of a simplified, flat statement of the problem. The analysis of the oscillations under impact. The wave field of displacements at a given part of the structure is analyzed. Based on a numerical experiment, an approach to estimating the characteristics of a layer is constructed.

Keywords: multi-layer construction, vibration diagnostics, simulation, FEM, Ansys, pulse action, dynamics, fluctuations

This article describes the method of dust emission suppression at a construction site. The results of the effectiveness of the developed equipment, fog formation gun, were obtained in the course of full-scale measurements in the course of stone installation works at the construction site in Rostov-on-don. The assessment of the air dustiness of the builder workplace and the degree of impact of the fog formation gun were attended with the statistical dependence of the number of dust particles PM2.5-PM10 . During the analysis, the following factors were studied: the location of the workplace at the construction site, the relative humidity and temperature. During the study, the following conditions were met: the premises were closed; the study was carried out in the process of performing stone installation works. The results of the experiment showed the effectiveness of the fog gun.

Keywords: environmental safety, fine dust, dust settling, dust suppression, ecology in construction, dust collectors, construction work, air protection, labor protection in construction, dust pollution

For a numerical study of the stress-strain state of the edge sections of a coal vein under the influence of a mining zone, there is a mathematical model of the geomass deformation processes, which is reproduced in the form of boundary value problems of the theory of elasticity. The problem was solved by the finite element method in a variational formulation, in which the functional was minimized with full potential energy to determine displacements in narrow of elements. Computational experiments were carried out using the author's complex of programs. Based on the results of numerical modeling, recommendations for strengthening the coal target and definitely bearing capacity was developed. The use of the developed mathematical model and software package allows us to design documents at the development stage, to predict the stress-strain state of the geomass in the zone of influence of the underground mining system.

Keywords: Mathematical model, numerical modeling, computational experiment, software package

The article reveals the essence and significance of the socio-cultural phenomenon-architectural competition. Features of its application in modern industrial architecture of Europe. Significant advantages of this type of project activity in the context of the specifics of the architecture of industrial enterprises are revealed.

Keywords: Architectural competition, creative competition, industrial architecture, modern architecture, environmental friendliness, energy efficiency, landscape environment, architecture of Europe

The article presents the results of testing samples of welded joints of polyethylene pipes for crack resistance at various temperatures. It is shown that in the weld zone a decrease in the stress intensity factor is observed up to 27% compared with the base material.

Keywords: Polymer, polyethylene, pipe, stretching, crack resistance, low temperatures, brittle failure, crack, welding, welded joint, fusion zone

In this article the comparative analysis of reinforcement of monolithic reinforced concrete plate under various conditions of calculation is made: without seismic actions, with design earthquake and with maximum design earthquake. It was found that taking into account the seismicity of 9 points without the use of methods of active seismic protection leads to an increase reinforcement to 28 % when taking into account the design earthquake and 81 % when calculating the maximum design earthquake. In addition, the analysis of the tool "Consumption of concrete and reinforcement" in the Lira-SAPR is made. The correction factor for the transition from theoretical to real reinforcement was obtained: it ranged from 2.4 to 3.0

Keywords: seismic impact, Lira-SAPR, maximum design earthquake calculation, frame calculation, slab, reinforced concrete, specific consumption of reinforcement

Durability of concrete, including fine-grained, with alternating cyclic temperature effect of the external environment is normalized according to GOST 26633 mark on frost resistance, and frost resistance criterion for all concrete in accordance with GOST 10060-2012 is the ratio of ultimate strength on compression of the main and control samples not less than 0.9 with a coefficient of variation of strength in the series, while for concrete road and airfield pavements is another additional criterion is the loss of mass. In the previous edition of GOST 10060, the ratio of the compressive strength of the main and control samples not less than 0.95 was adopted as the criterion of frost resistance for all concretes. GOST 31357 normalizes the indicator "frost resistance of the contact zone" for a number of mortars or fine-grained concretes obtained from dry building mixtures. This indicator characterizes the ability of the solution or fine-grained concrete to maintain the strength of adhesion to the concrete base after a certain number of freeze-thaw cycles. For the brand for frost resistance of the contact zone from Fkz25 to Fkz100, the number of cycles is taken, after which the decrease in the adhesion strength to the base does not exceed 20% according to GOST 31356, and in this case the coefficient of variation of the clutch values measured in the series is not taken into account. Due to the limited information on the change in the in-series coefficient of variation of strength after cyclic freezing-thawing, as well as the ratio of frost resistance by the criterion of compressive strength and adhesion strength to the base, the purpose of this study was to identify patterns of change in the in-series coefficient of variation of strength and adhesion strength to the base of fine-grained concretes obtained from dry building mixtures based on various Portland cements with the content of various redispersible polymer powders from 0 to 3%. The studies were carried out on the basis of 75 freeze-thaw cycles. This paper presents the results on the change in the coefficient of variation of strength after cyclic freezing-thawing and the ratio of frost resistance coefficients

Keywords: frost resistance of concrete, coefficient of variation of strength, coefficient of frost resistance, fine-grained concrete, dry mixes

The modeling of a hollow core slab in the finite element complex Ansys is considered. The construction of a 3D model is considered. Numerical modeling was carried out under static loading of the floor slab. The influence of material properties on the parameters of the stress state and deflection of the structure is investigated. Based on a numerical experiment, an approach to assessing the characteristics of a structure is constructed.

Keywords: hollow core slab, static analysis, modeling, FEM, Ansys, stress state, deflection

The article conentrates on the problem of synchronization the pseudo-noise sequence in direct sequence spread spectrum systems. Authors propose a method for transmitting information and synchronizing signals on a single carrier frequency, which allows data transmission in complex coditions in radio channel. A brief review of existing solutions for time synchronization direct sequence spread spectrum systems is carried out. The proposed solution is considered in terms of data transmission in broadband systems in the conditions of negative signal-to-noise ratio, while the limitations of the usage of this solution are also considered. A simulation of the scheme that implements the proposed synchronization method is carried out, and the requirements for the signal-to-noise ratio in the information and synchronization channels are determined. The proposed method can find application in systems with code division multiplexing, including modern IoT systems.

Keywords: time synchronization, direct sequence spread spectrum, broadband communication systems, Internet of Things, BER

Low-modulus inclusions in the form of entrained air or ash microspheres in the composition of fine-grained concrete practically do not affect the ratio of the ultimate strength in bending and compression during hardening of concrete under normal conditions. After 75 freezing-thawing cycles, the ratio of the flexural and compressive strengths of fine-grained concrete with ash microspheres did not change, and in concretes with involved air, the influence of factors such as the type and dosage of redispersible powder and the type of cement increased sharply. Low-modulus inclusions have practically no effect on the ratio between the initial elastic modulus and the compressive strength of fine-grained concrete during hardening under normal conditions. After 75 cycles of freezing and thawing in concrete with entrained air, the influence of such factors as the type and dosage of redispersible powder and the type of cement on the ratio of the initial elastic modulus to compressive strength increases sharply. The cyclic freezing-thawing does not affect on the ratio of module and strength in concretes with an ash microsphere. Regardless of the presence of low-modulus inclusions, there is no clear relationship between adhesion to a concrete base and flexural strength of fine-grained concrete. In concretes with entrained air, the increase in adhesion to the concrete base after 75 freezing-thawing cycles, depending on the type of cement and dosage of redispersible powder, was up to 82%, and for compositions with an ash microsphere, up to 62%. Regardless of the presence of low-modulus inclusions, after 75 freeze-thaw cycles, adhesion to the base corresponds to class C-1. With an increase in the dosage of redispersible powder from 0 to 3% in compositions with low-modulus inclusions, an increase in adhesion to the base was noted up to 62%.

Keywords: dry mortar mixes, redispersible polymer powders, low modulus inclusions, adhesion to the base, elastic modulus, tensile strength, freezing and thawing cycles

The article presents theoretical studies of the effect of various plasticizers on the mechanical properties of epoxy compositions. Based on this, the method of plasticization of the epoxy polymer ED-22 was chosen using the introduction of modified epoxy resin UP-563, which differs from the previously used modified compositions for repairing automotive vehicles in the field the simplicity of the availability of modifications in the field and as providing the widest range of changes in the properties of the epoxy composition for USAGE field. The scientific novelty lies in the justification for the creation of a new repair composition consisting of ED-22 epoxy-diane resin modified by UP-563 laproxil for the repair of hull and capacitive parts of automotive equipment in the field, which has increased vibration resistance. frost resistance and impact resistance.

Keywords: epoxy composition, epoxy resin, restoration, automotive engineering, body part, chemical modification, oligomer, polymer

In this paper, the previously obtained equation of motion in displacements is used to determine the frequencies and forms of free oscillations of the underground gas pipeline. The problem of solving this equation is reduced to finding the eigenvalues of the determinant, which are the squares of the natural frequencies of the cylindrical shell. Neglecting the secondary coefficients of the determinant and equating them to zero, the formula for the square of natural frequencies of an underground rectilinear thin-walled gas pipeline exposed to the action of internal working pressure and longitudinal force is obtained, taking into account the reaction of elastic resistance of the soil. Substituting the values for the wave numbers in the longitudinal and circumferential directions into the obtained formula, expressions for determining the frequencies according to the rod and shell theory are derived.Using these expressions, the dependence of the frequencies of free oscillations of the depth of the pipeline at fixed values of the pipe wall thickness, the coefficient of elastic resistance of the soil and the length parameter of the plot, for different values of internal pressure, the ratio of longitudinal compressive forces. When analyzing the results, it was found that with increasing depth of the pipeline, the frequency of free oscillations decreases, and at a certain depth, the frequency of free oscillations becomes equal to zero, this indicates a flattening of the cross section of the pipeline. Using the dynamic stability criterion, for which the frequency of free oscillations turns to zero, an expression is obtained that allows to determine the depth of the pipeline at which the stability loss of the second kind occurs.

Keywords: pipeline, frequency of free oscillations, depth of laying, coefficient of elastic resistance of soil, loss of stability

The article deals with the survey of transport and operational condition of the highway R224 " Samara-Orenburg in which it was found that the roadway surface is in poor condition due to the presence of transverse cracks, ruts and pits. In a survey of 5 existing culvert structures were identified unacceptable defects in the structure. Based on the foregoing, the specified section of road be repaired in accordance with GOST R 50597-2017 “roads and streets” . Currently, economical and mobile methods of inspection of road structures are of particular relevance. Conducting engineering surveys of the GPR system MIRA was determined the constructive layers of road clothes light. The decision on milling to a partial thickness of the pavement that runs recyclers WR 4200, with the subsequent device of asphaltgranulate type To

Keywords: pavement engineering, GPR applications, roads, surveys, MIRA GPR systempurposes of ensuring flexibility of production