The construction industry is considered to be one of the most unsafe industries, and as a result, safety in the construction industry is considered a very important factor. To reduce the number of accidents and monitor workers at a construction site, the article suggests integrating new tracking and communication technologies. The authors analyze the existing similar technological solutions, identify their advantages and disadvantages. A method for organizing monitoring of workers at a construction site using mobile devices is proposed, as well as the architecture of a software and hardware complex. The developed method is a smart system for a mobile device. This solution allows you to monitor the location of workers using a GPS tracker and a built-in accelerometer, and, if necessary, notify them of a possible danger.

Keywords: construction site, accidents, safety in construction, employee monitoring, mobile application, geolocation

The occurrence of convection in a two-layer system consisting of a region of a free fluid and a porous array saturated with the same fluid is investigated. The equations in the Oberbeck-Bussinesq approximation are used to describe the motion of a pure fluid, and the equations based on Darcy's law are used for the porous layer. Using the shifted grid scheme, the plane problem is approximated in natural variables. At the interface, special formulas derived by the integro-interpolation method and taking into account the different types of equations in the two domains are applied. The results of calculating critical numbers corresponding to the occurrence of convection for different heights of the porous layer and Darcy numbers are presented.

Keywords: dconvection, porous medium, Oberbeck-Boussinesq equations, Darcy model, shifted grids, stability

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

To provide protection class Br1, С and S2 (not less than 550 m/s) GOST 34286-2017 "Armor clothing. Classification and general technical requirements "use soft armored packages, consisting of several layers of aramid fabric of various surface densities and types of weaving. The most promising are armored packages consisting of fabric weaving, with a surface density of 0.130 kg/m2 and higher.

Keywords: soft armor pack, protection class Br1, protection class C, protection class S2 (not less than 550 m/s) armor protection, ballistic protection, aramid fabric, individual armor protection equipment

The article offers a solution which will enable to reduce dust pollution during earthworks in urban conditions. A special multi-functional mechanism is proposed enabling to perform several important preliminary processes simultaneously - improving an environmental situation on the site of earthworks. The ground surface damping during trench opening and soil unloading from a bucket into a disposal area will make it possible to reduce the fine dust pollution of the air surrounding a work location. The objective of the study is to develop a mechanism reducing the fine dust dispersal when performing trench and pit excavation. The novelty is that a mechanism of special construction has been proposed that can be mounted onto any machine in the construction line.

Keywords: earthworks, dispersal, technology process, trenching, single-bucket excavator, soil disposal area, trench, fine dust, air pollution, РМ 2,5, PМ 10

This article is devoted to the consideration of the possibility of using LED technologies in solving the problems of organizing artificial lighting of the historical part of the urban environment. A unique set of properties of modern LED sources, such as a wide dynamic color spectrum, low power consumption, ease of installation, long-term uninterrupted operation, environmental friendliness of production and operation, chemical and physical resistance to external influences, provides them with a steady demand for solving the problems of street and architectural lighting of historical quarters of the city, emphasizing their originality and uniqueness.

Keywords: artificial lighting, architectural lighting, lighting design, lighting systems, LED, LED technology, energy saving, environmental friendliness

The article is devoted to the analysis of the vertical structure of the acoustic pressure field and the first-mode particle velocity in a hydroacoustic waveguide in shallow water. A waveguide consisting of a water layer with a constant sound velocity profile, a transition layer, and a half-space is considered. The acoustic properties of the transition layer are assumed to be frequency dependent. Formulas are derived that describe the vertical profile of the normal mode of a particle velocity. The transformation of the vertical profile of the first mode with increasing frequency is analyzed. The phase difference relations between the normal mode of acoustic pressure and particle velocity are analyzed. A relationship is established between the change in the vertical structure of the normal modes of pressure and particle velocity and the acoustic properties of the transition layer.

Keywords: normal modes, particle velocity, seabed, attenuation coefficient

Numerical investigations of the dependences of the output characteristics of the ion strontium vapor laser on the pressure and temperature of the active medium were carried out. Based on the results of calculations, a range of conditions for the excitation of the active medium was found for the realization of the multiwave lasing regime on visible and infrared transitions of the strontium ion (λ=430.5; 416.2; 1091 and 1033 nm SrII). A number of patterns were revealed that are inherent in the active medium of a strontium vapor laser, and the physical mechanisms that determine them were established. The investigations results provide a possibility to choose the conditions for optimal excitation of multiwave strontium vapor lasers, as well as to control the relative contribution of various spectral components to the output radiation.

Keywords: multiwave radiation, recombination pumping, self-termination transition, strontium vapor laser, numerical modeling

This work is devoted to assessing the quality of the completed construction and installation work. A number of violations in the technology of facade works were noted. The advantage of a wet facade is noted. The main reasons for the occurrence of violations are considered. There are noted cases in which judicial intervention is required and it becomes necessary to conduct a forensic construction and technical examination. The main aspects that need to be paid attention to by specialists during the construction and technical expertise have been identified.

Keywords: low-rise buildings, facades, quality assessment, compliance, judicial construction and technical expertise, court case

The results of studies of the kinetics of the iron-catalytic oxidation of hydrogen sulfide by atmospheric oxygen in a reactor with a membrane separator are presented. The studies were carried out on a laboratory experimental complex. The dependences were obtained experimentally showing the effect of the catalyst dose - Fe (OH) 3¬, the pH of the medium, and the contact time of the water being purified with the reaction medium on the effect of water purification from hydrogen sulfide.

Keywords: hydrogen sulfide, iron catalytic oxidation, air oxygen, iron hydroxide, membrane separation, ultrafiltration

This article presents the results of identification and assessment of the factors of the working environment, as well as highlights the vibroacoustic factors that have the greatest impact on the working capacity and health of the operators of hoisting machines.

Keywords: identification, hoisting machines, acoustic discomfort, noise and vibration spectra, working conditions

The results of a theoretical and experimental study of the synthesis of GaInAsBi thin-film structures formed on InAs substrates in the field of a temperature gradient are discussed. The features of interfacial interaction in the In-As-Sb system in the presence of isovalent solvents (In, Bi) have been studied. The values ​​of the interaction parameters and the distribution coefficients of the system components are determined. Optimal technological modes for obtaining InAs-based heterostructures are presented. The properties of the surface of epitaxial layers are studied experimentally. It was found that the main control parameters are the temperature of thermomigration and its gradient. It is shown that the synthesized semiconductor materials can be effectively used in electronic devices of a new generation - electro-optical modulators and supersensitive sensor elements.

Keywords: epitaxial structure, crystallization, recrystallization, melt, segregation coefficient, organometallic compound, voltage sensitivity, near infrared range, solid solution, optical characteristic

The article discusses several types of wood frame house construction technology, primarily "Canadian technology". The rate of increase in construction in Russia is estimated. The structural materials of external enclosing structures used in frame housing construction are compared with the most commonly used components for construction. A comparative assessment of heat losses in percentage ratio during the operation of wooden frame houses and traditional ones is given. The pros and cons of frame housing construction are considered. A detailed analysis of the costs of construction and operation of wooden frame houses was made.

Keywords: frame house construction; Canadian technology; building materials; dynamics of price changes

The hardening of steel-making slags is slow and the strength properties of the cement stone do not provide the specified operational properties. By creating an optimal composition (steelmaking slag + blast furnace) and chemical activation, a composite material with high strength is obtained. The compressive strength of concrete samples at the age of 28 days of hardening in a normal hardening chamber is 28 to 54 MPa. Caustic soda and sodium silicate were used as a chemical activator of hardening. The greatest strength is provided by the ratio of chemicals as NaOH: Na2 SiO3 × nH2O = 1: 1 and at a dosage of 8% of the mass of the composite slag-alkali binder. The optimum ratio of ground granulated blast furnace slag and steelmaking slag is 3: 1 to obtain high compressive strength and minimum water absorption in the early stages of hardening.

Keywords: steelmaking slag, blast furnace slag, homogenization, hardening activator, hydration, strength

When creating a model of a nonlinear electrical system based on differential equations, it is important to keep in mind that ordinary differentiation does not give an adequate mathematical idea of ​​the nonlinear physical processes taking place. Even in the simplest case of a conductor with a current, the construction of an adequate model is only possible if the tensor approach is applied. From this point of view, any electrical system is an object of tensor methodology. A typical example of a non-linear electrical system is an AC electromagnetic drive. The nonlinear nature of the processes in such devices is due to a number of reasons. The main reasons are: current displacement in the winding of the AC electromagnetic drive and saturation of the steel of the magnetic circuit in the process of magnetization. Both phenomena admit tensor description, which is confirmed by the research presented in the article.

Keywords: dynamic characteristic of magnetization, electromagnet, mathematical model, tensor methodology