The paper presents the developed fiber-optic sensors for monitoring pressure measurement on the elements of mine supports. The sudden destruction of the support leads to the collapse of the mine workings and poses a serious threat to the life and safety of underground workers. A fiber-optic system for monitoring changes in pressures on the elements of mine supports will increase the share of mining automation and reduce the share of manual labor, as well as eliminate measurement errors associated with the human factor. Systematic monitoring of the state of the working elements of the support will allow timely tracking of their deformations caused by an increase in rock pressure on them. Implementation of the system at mining enterprises will expand the use of digital technologies in mining. Timely warning of a mine collapse threat will significantly increase the level of safe mining operations, as well as reduce the cost of supporting mine workings, since elimination of the consequences of destruction is associated with significant material costs. This work presents a developed laboratory testbench that simulates a mine working and elements of an arch support on which are installed the fiber-optic sensors connected to an automated measuring system. The developed hardware and software complex provides the processing of a light spot falling on the surface of a television matrix that is installed at the exit from the optical fiber. The results of visual processing are converted into numerical values, which are used to make a decision about the state of the considered object. In addition to automatic monitoring of the structural integrity condition of the considered object, the system is equipped with a function of a visual display for monitoring results, which makes it possible to track sharp fluctuations and bursts of pressure parameters, based on which the prediction of pre-emergency and emergency situations is performed.
26 April 2019 in IOP Conference Series: Materials Science and Engineering
The topicality of this work is due to the importance of developing such a new-generation monitoring computer-aided measurement system intended for ensuring the safety of mining works and coal mining...
1 July 2019 in Journal of Computational and Theoretical Nanoscience
By methods of quasi-classical kinetic theory investigated the mechanism of nonlinear protonrelaxation polarization in hydrogen bonded crystals (HBC), classified on electrophysical properties as proton semiconductors and dielectrics (PSND). Based on continuity equation of proton current constructed generalized kinetic equation nonlinear in the field, which allows describing proton relaxation in HBC, in the wide temperature range (1–1500 K) and electric field strengths (100 kV/m–1000 MV/m). The scheme is proposed, allowing, by the method of successive approximation (at small dimensionless parameter) build analytical solutions of the generalized nonlinear Fokker-Planck together with the Poisson equation. In this model blocking electrons adopted (work function of main charge carriers (protons) from the dielectric is equal to infinity). The scientific significance of received results consists in the applicability of this mathematical model, taking into account some model assumptions to description of relaxation polarization and conductance in heterogeneous dielectric structures (perovskites, or thoperiodates and biperiodates of alkali metals, ceramics, etc.), which are in demand in various fields of industry (microelectronics and optoelectronics, electrochemical technologies, hydrogen energy, etc.). In the future, the proposed theoretical methods will form the basis of algorithm for numerical optimization and computer prediction of structural materials parameters, which are functional elements of technological schemes of industrial installations and systems.
This paper is devoted to the development of generalized (for a wide range of fields (100 kV/m–1000 MV/m) and temperatures (0–1500 K) in the radio frequency range (1 kHz–500 MHz)) methods for the theoretical investigation of the physical mechanism of nonlinear kinetic phenomena during the establishment of the relaxation polarization, due to the diffusion motion of the main charge carriers in dielectrics with ionic–molecular chemical bonds (hydrogen-bonded crystals (HBC), including layered silicates, crystalline hydrates and corundum–zirconium ceramics (CZC), etc.) in an electric field. The influence of the nonlinearities equations of the initial phenomenological model of dielectric relaxation (in HBC-proton relaxation) on the mechanism for the formation of volume–charge polarization in solid dielectrics is analyzed. The solutions for the nonlinear kinetic Fokker–Planck equation, together with the Poisson equation, for the model of blocked electrodes are built in an infinite approximation (including all orders k of smallness without dimensional parameters) of perturbation theory for an arbitrary order r of the frequency harmonic of an alternating external polarizing field. It has been established that the polarization nonlinearities in ion-molecular dielectrics, already detected at the fundamental frequency, are interpreted in the mathematical model (for the first time in this work) as interactions of the relaxation modes of the volume charge density calculated on different orders of spatial Fourier harmonics. At the fundamental frequency of the field, an analytical generalized expression is written for complex dielectric permittivity (CDP), which is expressed analytically in terms of special relaxation parameters, which are quite complex real functions in the fields of frequency and temperature. The theoretical CDP and the dielectric loss tangent spectra studied depend on the nature of the relaxation processes in the selected temperature range (Maxwell and diffusion relaxation; thermally activated and tunneling relaxation), which is relevant from the point of view of choosing exact calculation formulas when analyzing the optimal operating modes of functional elements (based on dielectrics and their composites) for circuits of instrumentation, radio engineering and power equipment in real industrial production.
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.