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Inspection of the technical condition of load-bearing structural elements of buildings and structures in the process of their construction and operation is an important issue at the present time. A fiber-optic monitoring system is proposed as a solution to the problem of early diagnosis of defects and damage to load-bearing building structures. A scheme has been developed for testing fiber-optic sensors, which make it possible to control the stress-strain state of monolithic reinforced concrete structures. For testing, a series of monolithic concrete beams of rectangular cross section has been made reinforced with fiber optics during their manufacturing. The values of mechanical stresses and deformations arising in beams under loading have been determined. Using the tested samples as an example, it has been established that the proposed fiber-optic monitoring system (FOMS) makes it possible to control stresses and deformations (and to predict the appearance and growth of cracks) in various building structures. The main element of the system is a hardware-software complex capable of estimating the parameters of a light wave at the output of the optical fiber. The distance from the installation site of the data processing unit to the measurement point can cover the area of 30 km. At this, fiber-optic sensors operate without additional power supply from a laser with the power of up to 30 mW. The proposed monitoring system has a low cost of one measurement point, it is easy to install, which is a good alternative to the electronic beacon-recorder device and the development of optical digital technologies in construction.

Currently, there are many enterprises involved in extracting and processing of primary raw materials. The danger of working in this industry consists in the formation of cracks in rocks of the pit side slopes, which can lead to destruction. This article discusses the existing systems for monitoring the pit collapse prevention. The most promising is the use of systems with fiber-optic sensors. However, use of these systems is associated with some difficulties due to high costs, low noise immunity, and in some cases, the requirement for additional equipment to improve the reliability of measurements. A completely new method of processing the data from a fiber-optic sensor that simplifies the design and reduces the cost of the device is proposed considering the experience of previous developments. The system uses artificial intelligence, which improves the data processing. The theoretical part is dedicated to the development of foundations, and the analysis of the nonlinear properties of the physical and mathematical model of optical processes associated with the propagation of an electromagnetic wave in a fiber-optic material was developed. The results of experimental and theoretical applied research, which are important for the development of fiber-optic systems for monitoring the pit collapse prevention, are presented. The dependences of optical losses and the number of pixels on the dis-placement were obtained. The accuracy of the method corresponds to the accuracy of the device by which it is calibrated and is 0.001 mm. The developed hardware-software complex is able to track the rate of changing the derivative of the light wave intensity in time, as well as changing the shape of the spot and transition of pixels from white to black. [ABSTRACT FROM AUTHOR]

In this paper, the object of the research is 110 kV power grids of three regions of the Republic of Kazakhstan: Astana city, Turkestan region and Shymkent city, as well as West Kazakhstan region. Operators of the studied power grids have no idea about the real levels of voltage and current sinusoidality distortion coefficients, as well as about their relationship with other regime and system parameters of power grids. Similar problems may be faced by other grid companies that do not have the appropriate information and measurement infrastructure to monitor the modes of power grids in terms of voltage and current sinusoidality distortion. In the course of the present study, using portable three-phase power quantity and quality analyzers, it was possible to make daily measurements of mode parameters in 41 110 kV transmission lines with a length of 5 to 120 km. The results of measurements showed that in Astana city, the voltage quality is at a satisfactory level, but the distortion coefficient of sinusoidality of current reaches 39 % (the average level for 15 studied lines is 13.3 %) due to the high concentration of non-linear load of consumers. In the South of Kazakhstan, the voltage and current sinusoidality distortion coefficients are relatively moderate, but voltage drops are frequent (sometimes up to 10 % or more) due to the large distance between load centers and relatively high population density. In the power grids of Western Kazakhstan, voltage and current sinusoidality distortion coefficients have high levels (reach 14 % and 70 %, respectively) due to low network load with a large length of transmission lines. The analysis makes it possible to trace the relationship of voltage and current sinusoidality distortion coefficients with such regional characteristics as population density, nature of loads, power losses, voltage and current levels. [ABSTRACT FROM AUTHOR]

This paper presents the results of complex scientific research aimed at developing a prototype fiber-optic system for controlling the technical condition of buildings, structures, and extended objects. The aim is to develop a quasi-distributed type of fiber-optic control system without electrical signals, with the minimum possible cost of one measurement point. The fiber-optic sensors are based on a new method of controlling the parameters of the light spot by means of a hardware-software complex. The proposed monitoring system is quasi-distributed, is able to determine the damaged and most stressed and deformed areas of load-bearing reinforced concrete structures of buildings at the stage of their occurrence, and will allow for the taking of preventive measures for their protection. The research was carried out on a laboratory bench working together with the hardware-software complex; pixel analysis of changes in the area of the spot and its intensity was used as a fiber-optic sensor. A single-mode optical fiber of the G.652.D 9/125 μm standard was used, with a wavelength of 650 nm. The monitoring system can perform the function of pressure measurement on the building structure, establish the damage zone, and signal in case of an abrupt change in parameters in case of structure destruction. Laboratory tests have shown that the number of channels can be increased to 16 or 32. With the help of this system, it is possible to monitor the technical condition of the underground and above-ground parts of buildings or structures and control their integrity in real-time. [ABSTRACT FROM AUTHOR]

This article proposes several solutions for the use of novel AC voltage regulators as electrical energy quality conditioners and for the use of a half-bridge voltage inverter circuit as an active filter. This study was carried out with a real object, and more attention was paid to it. Structural models of electrical energy quality assurance systems, the calculation of control system elements and experimental results are presented. In particular, the use of a half-bridge voltage inverter circuit was considered as a replacement for the passive filter of the battery charger and rectifier device. AC voltage regulators are also used as compensators for higher-current harmonics, namely active filters and reactive power, voltage drop, voltage unbalance and flicker effect compensators. Block diagrams of power quality conditioners are presented, control algorithms are developed and the results of the current high-frequency harmonics compensation, reactive power and signal balancing are presented. The results of an active filter experiment based on the NRT 160.220 charge-rectifier device circuit showed a reduction in ripple of up to 1% with smaller dimensions compared to a passive filter. The control characteristics and external characteristics of the regulators are removed. The dependences of the current THD factor and the power factor are presented depending on the modulation depth for AC voltage regulator circuits used as power quality conditioners. [ABSTRACT FROM AUTHOR]

The article describes a system of power transmission via fiber-optic cable, which allows the supply of power to sensors and other electronic devices of ultra-low power located in places of mining workings, for which the mandatory requirement is fire safety. The developed system will allow to replace the application of copper conductors. The result of this research is the developed laboratory bench that allows measuring the current and voltage parameters in the photodetector branch. The equivalent generator method has been used, as well as the known circuit laws with two dedicated nodes for an active two-terminal network. When analyzing the literature, the existing scientific achievements, and discoveries in the field of research, an own concept of research has been formed that is different from foreign analogs. During the experiment, the studies have been performed when the photodetector was in the short circuit, idle mode, and connected to a high-resistance load. Based on the results obtained, current-voltage characteristics (CVC) and histograms have been built using a radiation source (laser) with a power of 10 and 30 mW. The parameters and technical characteristics of the irradiated silicon crystal and the radiation source have been given. The obtained electrical power has been determined using the known laws of electrical engineering, including the Ohm law. To process the experimental data, there has been used quadratic interpolation of the function, the results of the root-meansquare approximation, and there has been carried out the regression analysis. Absolute and relative errors have been calculated. The Student coefficient has been determined with a confidence interval of 0.95. Based on the results of the study, the efficiency of the power transmission system has been determined [ABSTRACT FROM AUTHOR]

In the article results of researches of brake devices of lifting machines UD of joint-stock company "ArcelorMittal Temirtau" are resulted. Defects were revealed as a result of the examination. A method and device for the unconditional control of defects and technical condition of the hinged joints of brake devices is developed in terms of the gap size and the angle of rotation between the links of the kinematic pairs "Widget-finger". For the monitoring of gaps, capacitive sensors are installed, mounted on hinged joints. It is substantiated that with the use of capacitive sensors it is possible to control the gaps in the hinged joints in real time. A device has been developed that makes it possible to estimate the magnitude of the gap at several points of the kinematic chain of the mechanism simultaneously.

This paper reports a study into designing an information-measuring system that could be used in coal mines that are dangerous in terms of the explosion of coal dust and methane gas. The results of reviewing technical advancements in the field of fiber-optic system development are given. To solve the set task, prototypes of a fiber-optic sensor of a new type and a hardware-software complex were constructed. The research aims to improve the safety of workers at coal enterprises. The result of the theoretical research has established that additional losses related to a micro bending should be taken into consideration while accounting for the effect of photoelasticity. The fundamental difference between the idea reported here and existing analogs is the development of a hardware-software complex capable of working with a single-mode optical fiber of great length with a significant noise level. The data processing unit is equipped with a television matrix and can analyze changes in the pixels of a light spot. The proposed system is quasi-distributed; it controls individual points within a rock massif. The designed hardware-software system provides high noise immunity of measuring channels when the external temperature changes. The research results helped develop an information-measuring system for monitoring the deformation and displacement of rock massif layers based on fiber-optic sensors, capable of operating in an explosive environment. The system makes it possible to control several layers located in the roof of the workings, while the fiber-optic sensor may contain two or three sensitive elements that are connected to different channels. With a sharp fluctuation in pressure and an increase in the displacement parameter, the system triggers a warning signal about the danger. [ABSTRACT FROM AUTHOR]

The study was devoted to solving the issue of creating new electric heating devices that can be used in autonomous heat supply systems. The issues were resolved by developing an original low-pressure electric steam heater. The study was aimed at improving the efficiency of heat supply systems for buildings and structures. Given the current trends in the global striving for energy conservation, it cannot be fully realized without the introduction of high-tech and low-energy- consuming electrical equipment. As a result of theoretical studies of a heat pipe with an electric heater, a design of an electrovacuum heating element has been developed. The low-pressure electric steam heater can be used in heat supply systems of autonomous users. Thermal energy transfer is currently accompanied by substantial energy losses since the heat carrier has to pass considerable distances. Switching of the facility to the heating plant is impossible in some cases because of technical problems or significant material costs for laying pipelines. As a result of the study, the dependence of heating the heat pipe at various volumes of the heat carrier and mass of the pipe itself was established. When a certain mass is reached, the temperature of the heating surfaces can reach 70 °C which is considered acceptable. The experimental data obtained have made it possible to develop an electric heater of new generation with a fundamentally new design of the heating element. It combines the efficiency of an electric spiral and comfortable warmth from a traditional radiator. This heater is an explosion and fire-safe and can be integrated into the Smart Home system. [ABSTRACT FROM AUTHOR]