Suspended ceilings constructions can improve the sound insulation of air and impact noise in civil buildings. To minimize the volume of the room, two types of suspended acoustic ceilings are most often used. They are: with the attachment of the structural shell of the ceiling close to the floor slab, and at a low suspension height. The influence of the slab's surface density on the correction to the sound insulation, which is created by the suspended ceiling, both in the first and in the second type, is considered. A method for a correction calculation for the sound insulation due to a suspended ceiling in these cases is given. At a minimum height the method is based on taking into account acoustic power's radiation coefficient of the shell. While for the low suspension height the method deals with the vibration's transmission from the floor slab to the ceiling's shell through the air layer and through the metal fasteners, that in this case become acoustic bridges. As a result, the formula of frequency response for sound pressure lowering, due to the sustained ceiling structure, is obtained. The influence of plasterboard suspended ceiling's perforation on the sound insulation of the entire floor structure is evaluated.

Keywords: suspended ceiling, impact noise isolation, airborne noise isolation, acoustic radiation power, limit frequency, acoustic bridge, acoustic impedance, vibration velocity level, porous and fibrous material, perforated plasterboard

The possibility of using nonlinear effects in hydroacoustic systems with parametric radiation mode for profiling the bottom and bottom sediments attracts the attention of both domestic and foreign specialists. The use of parametric antennas in hydroacoustic equipment allows, due to their high directivity and low side field level, to increase the information content and accuracy in detecting and determining the coordinates of underwater objects, and to obtain additional features for recognition. The efficiency of using a parametric profiler for solving problems that require high resolution is justified. A block diagram of a parametric profiler for studying the layered structure is developed. The features of the signal generator and the amplification unit are considered. The characteristics of the radiating antenna were measured under laboratory conditions. It is shown that the directivity characteristic is constant in the operating frequency range and the acoustic power at the output makes it possible to solve the tasks of sounding up to 10 m into the ground. A record of the soil profile was obtained, confirming the operability of the system. In the future, the results will be used in full-scale conditions with the use of cepstral echo processing.

Keywords: profilograph, parametric antenna, kepstr, block diagram, signal generator, power amplifier, directional pattern, amplitude-frequency response, pump antenna, ground profile

In this work, a survey of the hot water supply system from the boiler house No. 2 of Energoservice LLC was carried out. The daily schedule of hot water released for sanitary needs is given. The existing scheme of the boiler burner on-off control system is considered. A method for stabilizing the hot water preparation process by increasing the burner shut-off settings at the hour of the highest water consumption is found and described, and their values are found experimentally. A scheme has been developed, assembled and tested that allows you to adjust the operating mode of boilers at a strictly specified time of day. The proposed measure allowed us to solve the problem of selling hot water to consumers of a given quality during the maximum water intake period. In addition, the reduction in the generation of thermal energy for heating hot water at night and on weekends allowed for a 13.87% reduction in natural gas consumption in 2020.

Keywords: hot water supply, fuel consumption, pumping station, circulation line, conditional fuel, mode, boiler unit

The article discusses the natural factors that should be taken into account when designing highways. The following factors have a significant impact on the design of roads: terrain, engineering-geological and hydrogeological structure, climate, etc. The variety of natural factors is taken into account comprehensively in the design. They also take into account the negative impact of road construction on the environment. The terrain has an impact on fundamental engineering decisions, the volume of construction work, and ultimately not only on the construction cost of the highway and transport operating costs. In relation to the design of roads, there are five categories of terrain according to the complexity of road construction. Depending on the geological conditions, sometimes an extension of the highway route is used or expensive engineering measures are provided. It should be borne in mind that the use of the latest materials, road structures and new techniques for the production of construction areas is becoming less and the problems of seasonality of road reconstruction are becoming less relevant.

Keywords: highways, terrain, climate, slope, natural factors, engineering and geological process, surveys, tortuosity, lengthening of the route, road clothing

The article is devoted to the possibility of applying the methods of successive approximations in the analysis of the instantaneous scheme of the traction network. The described approach allows to improve the accuracy of modeling dynamic modes of operation of traction power supply sections, and also allows to significantly improve the process of modeling diagnostics and control systems of electric rolling stock at the design stage based on a more accurate model of dynamically changing input parameters of the traction network, depending on their required level.

Keywords: traction network, instantaneous circuit, diagnostics, simulation, recruitment model

The methodology of numerical experiment of laying with closed method by methods of horizontal-directional drilling, brown-screw drilling, forcing, microtonneling has been developed. Some features of the construction of cases for penetration by collectors under existing highways, including general information about the used materials of the cases, are given. A selection of controlled factors and experiment planning, system stability check, results reliability analysis was performed.

Keywords: collector, numerical experiment methodology, microtonneling, horizontal directional drilling, brown-screw drilling, puncture, forcing, motorway, case, reinforced concrete, metal pipes

The paper discusses approach to voice recognition, that allows to use tools of Google Cloud Speech platform for editing source code for programs, using audioprocessing, editing distances and substitution tables. The paper discusses issues of editing source code on mobile devices and the issues, which does not allow using tools from Google Cloud Speech platform directly, like not recognizing certain keywords. The paper suggests new method, which combines substitution tables and editing distances for solving the issues. This approach can be used for editing source code for programs, using mobile devices. The paper offers a prototypr of web-application, which allows to edit source code and uses this approach and, also, allows to submit changes to Github source code hosting platform and a popular instant messenger Telegram.

Keywords: voice recognition, mobile devices, source code analysis, formal languages, editing distances

This article discusses the theoretical order and practical solution of the problem of calculating the transverse vibrations of a thermosetting polymer self-supporting shell pipe " Furanflex».Сalculation scheme with a finite number of degrees of freedom.The pipe is evenly fixed in height.The procedure for creating a universal calculation algorithm for determining the natural frequencies of pipe vibrations is considered in detail.When creating an algorithm and calculating natural frequencies, determining coefficients, plotting plots, the Mathcad software package is used.When creating an algorithm and calculating natural frequencies, determining coefficients, plotting plots, the Mathcad software package is used. The article may be of interest to design engineers, specialists in calculating the dynamics and strength of structures and specialists of heat-generating companies and thermal power plants, teachers and students of universities in the construction industry.

Keywords: eigenvalues, polymer tube "furanflex", eigenvalues of the matrix

An experimental study of a quartz generator of the GK380-P-7VS-450M-3.3 s type was carried out.A description of the scheme and design is given. The results of the experiment are presented, including the frequency run-out, the frequency dependence on the supply voltage, and the output signal spectra for three different viewing bands. The following parameters of the output signal were obtained: the operating frequency of 450 MHz, the amplitude of the sinusoidal signal of 210 mV, the frequency run - out in 20 minutes of 550 Hz, frequency instability when the supply voltage changes 230 Hz, suppression of the second and third harmonics of at least 30 dB.

Keywords: quartz oscillator, frequency instability, frequency run-out, the amplitude of the sinusoidal signal, the spectrum of the output signal

This article discusses the theoretical order and practical solution of the problem of calculating the beam by the initial parameters method using the Mathcad calculation complex. The article describes in Detail and proposes the procedure for creating a universal calculation algorithm and program for any combination of vertical load. . Программа автоматизировано создает эпюры. The program automatically creates diagrams of internal force factors, displacements, rotation angles of beam sections.The article may be of interest to design engineers, specialists in calculating the dynamics and strength of structures, teachers and students of engineering Universities and the construction industry.

Keywords: method of initial parameters, beams, diagrams of internal force factors, beam movement, angles of rotation of sections

The paper is focused on research of an access control system based on the analysis of the thermal radiation of the user's palms using common components, it is shown that the use of multifactor biometric authentication based on the thermal image of the palms and infrared images of the user's veins allows to reduce the errors of the first and second kind during biometric authentication.

Keywords: biometric authentication, thermal palm print, access control system, infrared vein imaging

For the statically indeterminate systems under consideration, there is an optimal ratio between the load-bearing capacity of stretched and out-of-center compressed elements, in which the required reliability will be provided at the lowest value of the mathematical expectation of an external destructive load. It should also be noted that for statically indeterminate systems, the beginning of rebar fluidity is not a sign of destruction, but only indicates the beginning of an intensive redistribution of forces in it. Therefore, the values of C, do not refer to the beginning of the rebar flow, but to the complete exhaustion of the load-bearing capacity. The reliability of statically undetectable systems, including prestressed trusses, is always higher, all other things being equal, than that of statically definable systems.

Keywords: reinforced concrete, reinforced concrete structures, statically indeterminate systems, reliability

The emission of pollutants from wastewater disposal facilities has become a topic of increased interest, given its significant impact on the overall climate footprint of wastewater treatment plants. This paper presents comparative data in the field of air quality monitoring on the territory of domestic and industrial wastewater treatment plants abroad and in Russia. The issue of the influence of odors on human health is considered. Practical examples of the control of bad-smelling emissions are offered. A brief review of scientific papers on topics related to gaseous emissions from wastewater disposal systems is presented. Experimental studies of the quantities of specific components of the gas-air mixture above the surface of the waste liquid of the aeration tanks of the sewage treatment plants (CBS) of the city of Novoshakhtinsk, Rostov region are presented. Based on the analysis of the obtained results, technologies for reducing the amount of emissions from CBS facilities are considered.

Keywords: monitoring of air pollution, emissions, foul-smelling emissions, sulfur dioxide, aeration tank

The article considered the propagation of a long impulse signal in a hydroacoustic waveguide. A solution is given for a replica of a impulse signal in the second approximation of the dispersion theory. The propagation of a single-mode and multimode impulse in a Pekeris waveguide with a bottom in the form of an absorbing half-space is simulated. The acoustic properties of the half-space correspond to medium sand with an average grain size 0,3 mm. The result of the solution in the second approximation of the dispersion theory is compared with the result of the simulation of the impulse replica obtained as a convolution of the input signal with the impulse response of the waveguide. The disadvantages of the solution in the second approximation of the dispersion theory are shown and analyzed. It is shown that the theory of dispersion incorrectly reproduces the transients when the signal is switched on and off in cases where the signal frequency lies near the critical frequency of the first or second mode. It is shown that the theory of dispersion correctly reproduces the envelope of a multimode impulse signal.

Keywords: impulse signal, normal modes, group velocity, dispersion theory, intramode dispersion, intermode dispersion

The paper provides an overview of the applications in central heating points (CHP) of technologies and equipment to improve energy efficiency and quality of heat supply from district heating systems. The main equipment and characteristics of the hot water supply system taken as an example of the central heating station "MGU" are given. Described is the method of choosing the heating circuit of the central heating station from the ratio of the maximum loads of hot water supply and heating. For the adopted example of a central heating station, based on the above characteristics, the main indicator of energy efficiency is the specific consumption of electrical energy for the transport of thermal energy. Factors that have the greatest impact on this indicator: coefficient of uneven consumption of "hot water"; quality of regulation of hot water supplied to the hot water supply network; precise control of the productivity of the boosting and circulation pumping stations. The standard total power of the pump drives has been determined to be 13.58 kW and the range of actual power is from 10.79 kW to 22.04 kW.To reduce the influence of factors in the control scheme, it is proposed to use flow (pressure) regulators to maintain a constant direct-acting pressure drop. Use the pressure (pressure difference) of hot water discharged to the DHW system and returned from the system as balancing forces for this regulator. The parameters of hot water of rational modes of operation of the hot water supply system from the central heating station "MGU" were determined: temperature of hot water at the outlet of the heat exchange equipment 75 ° С; hot water pressure at the outlet of the heat exchange equipment 45 m; hot water pressure at the inlet of the circulation pump 25 m. The implementation of the proposed option without the inertial control scheme for the temperature of "hot water" and the developed rational modes of operation of the hot water supply system, according to the assessment of efficiency indicators, will reduce the specific consumption of electrical energy in the central heating station by 28.4% from 0.631 kW * h / m3 to 0.452 kW * h / m3.

Keywords: central heating station, hydraulic mode, flow regulator, pump characteristic