scholarly journals Leaky Feeder System Optimizations In Underground Mines And Tunnels

2021 ◽  
Author(s):  
Wisam F. Farjow
Keyword(s):  
Communication Networks ◽  
Communication Systems ◽  
Underground Mines ◽  
System Stability ◽  
Mining Operations ◽  
Stability Problems ◽  
Reliable Communications ◽  
Increasing Demand ◽  
Novel Algorithms ◽  
The Stability

There is an increasing demand for reliable communications systems in underground mines and tunnels. This is especially true when these systems need to ensure the safety of personnel involved in the mining operations and also to provide infrastructure for mine's communication networks. Stability problems are among the challenges of providing reliable communications in the underground mines. This thesis has focused on analyzing the stability problems in the communication systems of leaky cable technology. Novel algorithms have been developed to provide Automatic Gain and Slope Controls for the leaky feeder communication systems in the underground mines. The new algorithms are based on predications. The amplifiers in the system cascade will be able to predict and compensate for losses yet to occur in the system. System stability will be improved as a result of applying these algorithms by controlling the gains and the slopes of the amplifiers in the systems.

scholarly journals Leaky Feeder System Optimizations In Underground Mines And Tunnels

2021 ◽  
Author(s):  
Wisam F. Farjow
Keyword(s):  
Communication Networks ◽  
Communication Systems ◽  
Underground Mines ◽  
System Stability ◽  
Mining Operations ◽  
Stability Problems ◽  
Reliable Communications ◽  
Increasing Demand ◽  
Novel Algorithms ◽  
The Stability

There is an increasing demand for reliable communications systems in underground mines and tunnels. This is especially true when these systems need to ensure the safety of personnel involved in the mining operations and also to provide infrastructure for mine's communication networks. Stability problems are among the challenges of providing reliable communications in the underground mines. This thesis has focused on analyzing the stability problems in the communication systems of leaky cable technology. Novel algorithms have been developed to provide Automatic Gain and Slope Controls for the leaky feeder communication systems in the underground mines. The new algorithms are based on predications. The amplifiers in the system cascade will be able to predict and compensate for losses yet to occur in the system. System stability will be improved as a result of applying these algorithms by controlling the gains and the slopes of the amplifiers in the systems.

scholarly journals Advanced diagnostic system for underground communication networks with ventilation on demand

2021 ◽  
Author(s):  
Mohamed Daoud
Keyword(s):  
Communication Networks ◽  
Communication Systems ◽  
Communication Protocol ◽  
Diagnostic System ◽  
Underground Mines ◽  
Control Room ◽  
Specific System ◽  
On Demand ◽  
Underground Communication ◽  
Receiver Unit

In this thesis, a novel diagnostic system has been developed to increase the realibility of leaky feeder communication systems in underground mines. The new system is based on three main parts: 1) Diagnostic Receiver Unit (DRU) located in the control room above ground; 2) several Diagnostic Transponder Units (DTU) connected to amplifiers, Power Supply Units (PSU), fans and sensors; and 3) Communication protocol that was designed for this specific system. The amplifiers, PSU, fans, and sensors in the system cascade will be able to communicate freely with the control room through the leaky cable to send information about their current conditions, and receive configuration messages. A new concept is also presented that provides energy saving in mines; Ventilation-on-Demand where the fans will operate according to the current situation of each section in the mine. This is made possible through a series of interrupt messages that is sent from the DTU attached to the fan/sensor to the DRU in the control room.

scholarly journals Advanced diagnostic system for underground communication networks with ventilation on demand

2021 ◽  
Author(s):  
Mohamed Daoud
Keyword(s):  
Communication Networks ◽  
Communication Systems ◽  
Communication Protocol ◽  
Diagnostic System ◽  
Underground Mines ◽  
Control Room ◽  
Specific System ◽  
On Demand ◽  
Underground Communication ◽  
Receiver Unit

In this thesis, a novel diagnostic system has been developed to increase the realibility of leaky feeder communication systems in underground mines. The new system is based on three main parts: 1) Diagnostic Receiver Unit (DRU) located in the control room above ground; 2) several Diagnostic Transponder Units (DTU) connected to amplifiers, Power Supply Units (PSU), fans and sensors; and 3) Communication protocol that was designed for this specific system. The amplifiers, PSU, fans, and sensors in the system cascade will be able to communicate freely with the control room through the leaky cable to send information about their current conditions, and receive configuration messages. A new concept is also presented that provides energy saving in mines; Ventilation-on-Demand where the fans will operate according to the current situation of each section in the mine. This is made possible through a series of interrupt messages that is sent from the DTU attached to the fan/sensor to the DRU in the control room.

Stability of Synchronized States in One Dimensional Networks of Second Order PLLS

1997 ◽  
Vol 07 (03) ◽  
pp. 681-690
Author(s):  
Hisa-Aki Tanaka ◽  
Maria de Sousa Vieira ◽  
Allan J. Lichtenberg ◽  
Michael A. Lieberman ◽  
Shin'ichi Oishi
Keyword(s):  
Communication Networks ◽  
Communication Systems ◽  
Nearest Neighbor ◽  
Digital Communication ◽  
Early Stage ◽  
Building Blocks ◽  
Second Order ◽  
Phase Detector ◽  
Phase Locked Loops ◽  
The Stability

Synchronous distributed timing clocks are the basic building blocks in digital communication systems. Conventional systems mainly employ a tree-like network of cascaded timing clocks for synchronous clocking. On the other hand, decentralized synchronous networks of timing clocks, which have been proposed from a very early stage of the digital communication, are gaining attention in the consumer communication networks and also recently in large, high-performance digital systems (such as multiprocessors) clocking. In this paper, we present a theoretical study of synchronous networks of timing clocks consisting of locally connected second order phase-locked loops (PLLs). We find a close connection between the stability properties of the first and second order networks. The particular examples of one way and two way nearest neighbor coupling, with a lag-lead filter and a triangular phase detector (PD) are analyzed in detail. Both the synchronized in-phase solution and the wave-like "mode-lock" solution are examined. A criterion is found for the stability of the one-way coupled network while the two-way coupled network is found to be always stable.

scholarly journals Geological CO2 quantified by high-temporal resolution stable isotope monitoring in a salt mine

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Alexander H. Frank ◽  
Robert van Geldern ◽  
Anssi Myrttinen ◽  
Martin Zimmer ◽  
Johannes A. C. Barth ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Underground Mining ◽  
Stable Carbon Isotope ◽  
Underground Mines ◽  
Background Concentration ◽  
High Temporal Resolution ◽  
Salt Mine ◽  
Gas Migration ◽  
Mining Operations ◽  
Anthropogenic Contributions

AbstractThe relevance of CO2 emissions from geological sources to the atmospheric carbon budget is becoming increasingly recognized. Although geogenic gas migration along faults and in volcanic zones is generally well studied, short-term dynamics of diffusive geogenic CO2 emissions are mostly unknown. While geogenic CO2 is considered a challenging threat for underground mining operations, mines provide an extraordinary opportunity to observe geogenic degassing and dynamics close to its source. Stable carbon isotope monitoring of CO2 allows partitioning geogenic from anthropogenic contributions. High temporal-resolution enables the recognition of temporal and interdependent dynamics, easily missed by discrete sampling. Here, data is presented from an active underground salt mine in central Germany, collected on-site utilizing a field-deployed laser isotope spectrometer. Throughout the 34-day measurement period, total CO2 concentrations varied between 805 ppmV (5th percentile) and 1370 ppmV (95th percentile). With a 400-ppm atmospheric background concentration, an isotope mixing model allows the separation of geogenic (16–27%) from highly dynamic anthropogenic combustion-related contributions (21–54%). The geogenic fraction is inversely correlated to established CO2 concentrations that were driven by anthropogenic CO2 emissions within the mine. The described approach is applicable to other environments, including different types of underground mines, natural caves, and soils.

scholarly journals Water-retaining properties of NCZ composite dust suppressant and its wetting ability to hydrophobic coal dust

2021 ◽  
Author(s):  
Jianguo Liu ◽  
Shu Wang ◽  
Longzhe Jin ◽  
Tianyang Wang ◽  
Zihao Zhou ◽  
...  
Keyword(s):  
Least Squares Method ◽  
Coal Dust ◽  
Water Injection ◽  
Synthesis Method ◽  
Underground Mines ◽  
Initial Contact ◽  
Clean Water ◽  
Mining Operations ◽  
Thermal Synthesis ◽  
Wetting Ability

AbstractCoal dust is a primary threat to underground coal miners. The most common approach to control coal dust is hydraulic methods, such as water spray and coal seam water injection. To improve the dust suppressant efficiency of hydraulic methods, a novel chemical composite dust suppressant, called NCZ, was prepared in this study using calcium chloride (CaCl2), magnesium chloride (MgCl2), and nonionic surfactants using a thermal synthesis method. The water-retaining properties of NCZ powder and its solutions were characterized using the water absorption rate (WAR) and evaporation rate (ER), respectively, and the wetting abilities of the NCZ solutions on coal dust were tested using the initial contact angle (ICA) and sink rate (SR). The results indicate that the NCZ solutions have anti-evaporation effects, and the ER of the solution with a 20.0 wt% NCZ is reduced by 11.7% compared with that of clean water. Furthermore, NCZ solutions have remarkable enhancement effects on the wettability of coal dust. The ICA and SR of clean water and the NCZ solution at 20.0 wt% are 141.9° and 0 mg/s, and 29.3° and 1.46 mg/s, respectively. Finally, quantitative relationships between the solution surface tension and the ICA and IR were established using the least squares method. This study provides a new product for dust suppression in underground mines, which is significant for the optimum applied concentration of dust suppressant in mining operations.

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

scholarly journals Study on the Deformation Mechanism of Soft Rock Roadway under Blasting Disturbance in Baoguo Iron Mine

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Hong-di Jing ◽  
Yuan-hui Li ◽  
Kun-meng Li
Keyword(s):  
Rock Mass ◽  
Deformation Mechanism ◽  
Soft Rock ◽  
Deformation Monitoring ◽  
Underground Mines ◽  
Blasting Vibration ◽  
Iron Mine ◽  
The Stability ◽  
Soft Rock Roadway ◽  
Rock Roadway

In order to study the deformation mechanism of soft rock roadway in underground mines, it is necessary not only to study the influence of the dynamic disturbance caused by the cyclic mining blasting vibration on the stability of the soft rock roadway but also to study the degradation of the roadway surrounding rock itself and other factors. The paper presented a synthetic research system to investigate the factors that influence roadway rock structure deterioration in Baoguo Iron Mine. Firstly, the stability of rock mass was analyzed from the perspective of the physical and structural characteristics of the rock mass. Afterwards, according to monitoring data of mining blasting vibration, a suitable safety blasting prediction model for Baoguo Iron Mine was determined. And then, combining the results of mining blasting vibration monitoring and deformation monitoring, the effect of cyclic mining blasting on the stability of the soft rock roadway was obtained. By systematically studying the intrinsic factors of rock quality degradation and external environmental disturbances and their interactions, this paper comprehensively explores the deformation mechanism of soft rock roadway and provides the support for fundamentally solving the large deformation problems of soft rock roadway in underground mines.

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