Evaluation of the possibility of wireless data transmission over rocks for automating an alarm system in mines using lowfrequency electromagnetic waves and radio tags

The paper discusses the possibility of organizing a wireless data transmission channel in place of different kinds of mines for signalling and emergency communication using electromagnetic waves in the VLF propagation (300 Hz - 3 kHz). The paper gives theoretical estimates of the efficiency of propagation of electromagnetic waves in rocks and minerals with different values of electrical conductivity. The dependence of the depth of penetration on frequency is also studied. A review of the existing technical solutions to this problem is given. An analytical and numerical analysis of the current density in the rock and the magnetic field created by it using a radiating long cable is given. Reception of a signal with an informational message is carried out with the help of an individual radio tag informing personnel both in conditions of the mine's normal operation and in emergency situations. Comparative evaluations of the efficiency of using radio tags with different configurations of a receiving antenna in mine conditions at a depth of up to 800 m are give

Analysis and development of a digital radar flaw detector for robotic defect detection systems

The purpose of this study is to develop a software and hardware complex for robotic defect detection systems, which will reduce the measurement time and reduce labor costs. The main method of detecting defects in this article is the registration of the effect of a change in the resonant frequency of oscillations of rail lashes due to the formation of defects. Simulation and evaluation of the effect of linear dimensions of defects for a regular cylinder and a sphere is given. It is shown that even defects with sizes up to 1 mm give frequency shifts for the first harmonic up to 10 Hz, and also data are given on the formation of additional oscillatory modes from the position of the defect relative to the edges of the rail lash. The second part of the article contains materials on the development of software and hardware for recording vibration data by a radar metho

Development of a non-explosive water source of seismic acoustic waves with an electromagnetic drive to automate the work in transit zones and in shallow water

The paper examines the theoretical aspects of the excitation of seismic waves in the aquatic environment, addresses the problems of instrumental implementation of a fundamentally new source of seismic vibrations that can work in the waters, in tidal and coastal zones, i.e. produce continuous seismic profiling from the water area to the land. The scientific substantiation of the developed SI design is given. The effectiveness of two polar excitation of the aquatic environment is evaluated in comparison with the water electromagnetic pulse sources of the Yenisei series. The comparative analysis results of SR experimental model effectiveness with VEM-50 production model of the "Yenisei" model range is given on the basis of experimental data obtained at the geophysical well of the testing and testing ground of the Siberian Federal University

Non-linear FM demodulation with neural networks in through-the-earth mine communications

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.Classical methods of FM demodulation used in through-the-earth mine communications rely heavily on an assumption of Gaussian random noise. Such assumption ignores many possible non-linear effects which may affect signal-to-noise ratio at the receiver and lead to increase in bit error. We propose a simple technique based on convolutional neural network which is robust to possible non-linear effects. Our field study demonstrates that such effects do occur in through-the-earth communications and that the distorted signal at the receiver can still be demodulated with reasonably low bit error rate

Theoretical and experimental validation of seismoelectrical method

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.The main aim of this study is a theoretical and experimental validation of the method based on a recording of the seismoelectrical effect upon excitation of seismic fields by the special non-explosive striker and without an additional source of the electromagnetic field. Signals of seismic and electrical fields were recorded using earthed electric dipoles and seismic receiver with subsequent processing using seismic acquisition system. The frequencies of recorded fields were in the range of 0.1-20 Hz. The observation results of seismoelectrical effect resulted from excitation of the geological section by seismic shocks (a KEM-4 striker) and recording of secondary electrical and seismic fields on the surface by measurements of their cross-correlation function. The activities were performed during July 23-30, 2017 on Bystryansky gas condensate field (Krasnoyarsk Krai, Minusinsk district). The productive deposit was indicated by the maximum coefficient of cross-correlation by three times higher than normal background. 3D maps of the seismoelectrical section were obtained for the first time