scholarly journals Recapitulation and Prospect of Research on Flow Field in Coal Mine Gob

2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Rui Zhang ◽  
Jianwei Cheng ◽  
Zui Wang ◽  
Zhenlu Shao
Keyword(s):  
Flow Field ◽  
Coal Mine ◽  
Quantitative Research ◽  
Numerical Models ◽  
Research Direction ◽  
Overburden Failure ◽  
Fracture Development ◽  
Porosity And Permeability ◽  
Combustible Gases ◽  
And Control

Coal mine gob, mined-out areas in underground coal mines, often accumulates explosive methane-air mixtures that pose a deadly hazard to miners. A good understanding of the flow field in a sealed coal mine area is crucial in preventing and minimizing accidents associated with mine combustible gases and also for planning and implementing a mine rescue strategy. In recent years, the research on the flow field in the gob has changed from qualitative research in the past to quantitative research. This paper synthesizes the research results of flow field in gob in recent 40 years, covering the permeability of quarried areas, the airflow simulation in quarried areas, and the influence of ventilation parameters and geohydrological conditions on the flow field. Firstly, the overburden failure mechanism and fracture development characteristics of the mine gob, the distribution of porosity and permeability in the gob, and the relationship between them are introduced. Secondly, the development of research methods and numerical models used to study the flow field in mine gob is discussed. The distribution of the flow field in the gob under different conditions is expounded. Thirdly, the research on the prevention and control of fire and explosion risks in the gob is discussed. Finally, the problems to be solved in such research direction are addressed and suggestions are put forward.

scholarly journals Identification of Hydraulic Connection Points between Different Confined Aquifers in the Liyazhuang Coal Mine

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhenghe Liu ◽  
Peiyun Zhao ◽  
Lusheng Yang ◽  
Jingui Zhao ◽  
Hailong Ye ◽  
...  
Keyword(s):  
Flow Field ◽  
Coal Seam ◽  
Numerical Simulations ◽  
Water Level ◽  
Coal Mine ◽  
Prevention And Control ◽  
Water Inrush ◽  
Hydraulic Connection ◽  
Contact Points ◽  
And Control

Water inrush from coal seam floors is one major geological obstacle hindering safe and efficient production activities in mines. Determining the source of water inrush can facilitate its prediction and guide decisions regarding measures for prevention and control. The process of identifying the location of hidden hydraulic contact points in different confined aquifers forms the basis of hydrogeological explorations. It is also the basis for categorizing mine areas prone to water inrush and making qualitative decisions regarding the prevention and control of water inrush. In this study, the positions of hidden hydraulic contact points between the Ordovician Fengfeng and Shangmajiagou formations in the basement of the Liyazhuang coal mine were determined using numerical simulations of the flow fields. First, each node of the finite element grid was considered as a water inrush point to determine the water level at other nodes. Subsequently, the error between measured and simulated water levels, determined based on the flow fields, was determined using the least squares method. The node with the minimum error was then considered as the hidden hydraulic contact point. The simulation results for the flow field indicate a distance of 5000 m between the hydraulic connection and the water inrush points located between the peak formation and the Majiagou aquifer in the Liyazhuang coal mine. Furthermore, the hydraulic relationship between them is poor. Observational data of water inrush from the floor of the No. 2 coal seam and the water level of the confined aquifer in the Liyazhuang coal mine, including the water quality test data of different Ordovician ash aquifers, show that the source of water inrush from the floor of the No. 2 coal seam is the aquifer of the Fengfeng Formation. This finding is consistent with the results of the numerical simulations of the flow field. The results demonstrate that, in mining areas subjected to high pressures, numerical simulations of the flow field can serve as an effective tool for determining the location of hidden hydraulic contact points.

scholarly journals The Impact of Socially Responsible Reporting on Successful Corporate Operations

Organizacija ◽  
2013 ◽  
Vol 46 (2) ◽  
pp. 47-54 ◽  
Author(s):  
Anton Peršič ◽  
Mirko Markič
Keyword(s):  
Research Method ◽  
Quantitative Research ◽  
Socially Responsible ◽  
The Real Estate ◽  
Construction Market ◽  
Responsible Conduct ◽  
The Republic ◽  
And Control ◽  
The Impact ◽  
A Company

The aim of our research was to study the impact and purpose of the reporting on socially responsible conduct on the success of corporate operations. The data and information were gathered with the quantitative research method, whereas the instrument for gathering them was a questionnaire that was distributed among 759 large and medium sized organisations from the field of market services in the Republic of Slovenia. We have established that activities aimed at socially responsible conduct are directly connected with the success of corporate operations, especially the revenue (p = 0.001), the profit of a company (p = 0.000), operational growth (p = 0.007) and operational economy (p = 0.002), and are typical for organizations with a larger number of employees (p = 0.032). In this regard, the real estate and construction market activities received the lowest scores. Research results provide theoretical as well as practical benefits for everyone dealing with the planning, implementation and control of sustainable development, as well as socially responsible conduct within the organization.

scholarly journals New integrated monitoring and control system for disaster gas application in coal mine

2017 ◽  
Vol 191 ◽  
pp. 012051
Author(s):  
Deng-yu Zhao ◽  
Xing-ping Lai ◽  
Chang-fa Ji ◽  
Hong-jun Xi ◽  
Zhang Bo ◽  
...  
Keyword(s):  
Control System ◽  
Coal Mine ◽  
Monitoring And Control ◽  
Integrated Monitoring ◽  
Monitoring And Control System ◽  
And Control

scholarly journals Sparse stabilization and control of alignment models

2014 ◽  
Vol 25 (03) ◽  
pp. 521-564 ◽  
Author(s):  
Marco Caponigro ◽  
Massimo Fornasier ◽  
Benedetto Piccoli ◽  
Emmanuel Trélat
Keyword(s):  
Policy Maker ◽  
Research Direction ◽  
Fundamental Question ◽  
Self Organization ◽  
Group Consensus ◽  
Future Developments ◽  
Consensus Dynamics ◽  
Time Optimal ◽  
And Control ◽  
Mathematical Justification

Starting with the seminal papers of Reynolds (1987), Vicsek et al. (1995), Cucker–Smale (2007), there has been a lot of recent works on models of self-alignment and consensus dynamics. Self-organization has so far been the main driving concept of this research direction. However, the evidence that in practice self-organization does not necessarily occur (for instance, the achievement of unanimous consensus in government decisions) leads to the natural question of whether it is possible to externally influence the dynamics in order to promote the formation of certain desired patterns. Once this fundamental question is posed, one is also faced with the issue of defining the best way of obtaining the result, seeking for the most "economical" way to achieve a certain outcome. Our paper precisely addressed the issue of finding the sparsest control strategy in order to lead us optimally towards a given outcome, in this case the achievement of a state where the group will be able by self-organization to reach an alignment consensus. As a consequence, we provide a mathematical justification to the general principle according to which "sparse is better": in order to achieve group consensus, a policy maker not allowed to predict future developments should decide to control with stronger action the fewest possible leaders rather than trying to act on more agents with minor strength. We then establish local and global sparse controllability properties to consensus. Finally, we analyze the sparsity of solutions of the finite time optimal control problem where the minimization criterion is a combination of the distance from consensus and of the ℓ1-norm of the control. Such an optimization models the situation where the policy maker is actually allowed to observe future developments. We show that the lacunarity of sparsity is related to the codimension of certain manifolds in the space of cotangent vectors.

A Design of Coal Mine Security Monitoring Substation Based on ZIGBEE and CAN Bus

2014 ◽  
Vol 971-973 ◽  
pp. 1033-1036
Author(s):  
Hui Jun Wang ◽  
Zhi Qun Yong
Keyword(s):  
Coal Mine ◽  
Can Bus ◽  
Measurement Data ◽  
Environmental Parameters ◽  
Monitoring And Control ◽  
Monitoring And Control System ◽  
Security Monitoring ◽  
Mine Development ◽  
Security Monitoring System ◽  
And Control

In view of the shortcoming such as wiring difficulties, poor scalability, and big cable usage in present mine security monitoring system, this paper puts forward a kind of substation monitoring and control system based on ZIGBEE and CAN. With the core of core, The system collects various measurement data of sensors through the ZIGBEE wireless network, realizes the to collect, and then through the CAN bus to realize the transmission of control commands and data of the up and down machine, and monitor the production parameters and environmental parameters in the coal mine. Experiments show that the monitoring substation is of high real-time performance, good stability, strong expansibility, etc., and can meet the requirements of the coal mine development and mining.

Impacts of Coal Mining on Groundwater Environment in Northwestern Coal Mine Area

2013 ◽  
Vol 448-453 ◽  
pp. 823-829
Author(s):  
Hao Wang
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Water Cycle ◽  
Numerical Models ◽  
Pumping Test ◽  
Field Investigation ◽  
Groundwater Pumping ◽  
Mine Area ◽  
Groundwater Environment ◽  
Groundwater Flow Field

By conducting field investigation and tests, such as groundwater pumping test and rock mechanics test, and building numerical models to simulate damage of coal mining to aquifers, it was proved that coal mining in some coal mine area caused impacts to groundwater environment, including impact on water cycle, the structure of aquifers, and groundwater flow field, as a result of which some water supply sources in coal mine area become unavailable. In addition, a couple of solutions are presented to mitigate the impacts.

scholarly journals Stability Control of Deep Coal Roadway under the Pressure Relief Effect of Adjacent Roadway with Large Deformation: A Case Study

2021 ◽  
Vol 13 (8) ◽  
pp. 4412
Author(s):  
Houqiang Yang ◽  
Nong Zhang ◽  
Changliang Han ◽  
Changlun Sun ◽  
Guanghui Song ◽  
...  
Keyword(s):  
Large Deformation ◽  
Coal Mine ◽  
High Stress ◽  
Surrounding Rock ◽  
Western China ◽  
Engineering Practice ◽  
Pressure Relief ◽  
Coal Roadway ◽  
And Control ◽  
Relief Effect

High-efficiency maintenance and control of the deep coal roadway surrounding rock stability is a reliable guarantee for sustainable development of a coal mine. However, it is difficult to control the stability of a roadway that locates near a roadway with large deformation. With return air roadway 21201 (RAR 21201) in Hulusu coal mine as the research background, in situ investigation, theoretical analysis, numerical simulation, and engineering practice were carried out to study pressure relief effect on the surrounding rock after the severe deformation of the roadway. Besides, the feasibility of excavating a new roadway near this damaged one by means of pressure relief effect is also discussed. Results showed that after the strong mining roadway suffered huge loose deformation, the space inside shrank so violently that surrounding rock released high stress to a large extent, which formed certain pressure relief effect on the rock. Through excavating a new roadway near this deformed one, the new roadway could obtain a relative low stress environment with the help of the pressure relief effect, which is beneficial for maintenance and control of itself. Equal row spacing double-bearing ring support technology is proposed and carried out. Engineering practice indicates that the new excavated roadway escaped from possible separation fracture in the roof anchoring range, and the surrounding rock deformation of the new roadway is well controlled, which verifies the pressure relief effect mentioned. This paper provides a reference for scientific mining under the condition of deep buried and high stress mining in western China.

PENGARUH EDUKASI PERAWAT TERHADAP KETEPATAN KELUARGA PASIEN MELAKUKAN CUCI TANGAN DALAM PENCEGAHAN PENULARAN COVID-19 DI RSUD ARIFIN ACHMAD PROVINSI RIAU

2021 ◽  
Vol 3 (4) ◽  
pp. 70-74
Author(s):  
Nurul Utami
Keyword(s):  
Quantitative Research ◽  
Public Awareness ◽  
Nurse Education ◽  
Hand Washing ◽  
P Value ◽  
Average Value ◽  
High Incidence ◽  
Quasi Experimental ◽  
And Control ◽  
Source Of Information

Corona virus is a virus that attacks the respiratory system. The high incidence of Covid-19 is due to low public awareness of applying health protocols. So the need for prevention and control efforts by complying with health protocols to wear masks, keep your distance and wash your hands properly. Washing hands is an easy routine and is important in infection control, and is the best method to prevent the transmission of microorganisms. The purpose of this study was to determine the effect of nurse education on the accuracy of the patient's family through hand washing in preventing Covid-19 transmission at Arifin Achmad Hospital, Riau Province. This research uses quantitative research with a quasi experimental design, with a population of 20 people. Data collection tools used observation sheets and data analysis was carried out univariate and bivariate with the Wilcoxson test. The results of this study show that the average value before being given education about hand washing is low compared to the average value after being given education about hand washing. So that hand washing education is effective in increasing hand washing to prevent Covid-19 transmission with a p-value of 0.000. The results of this study are expected to be a source of information and knowledge for the nursing profession regarding the effect of providing nurse education on the accuracy of the patient's family in washing hands.

scholarly journals Influence of Extreme Temperature on the Pore and Fracture Development of High-Rank Coal

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ming Yang ◽  
Jingcang Bi
Keyword(s):  
Temperature Stress ◽  
Pore Volume ◽  
Coal Sample ◽  
High Rank ◽  
Research Attention ◽  
Ultralow Temperature ◽  
Distribution Features ◽  
Fracture Development ◽  
Porosity And Permeability ◽  
Coal Reservoir

Pore and fracture structures in coals and their distribution features play an important role in the enrichment and osmosis migration of coalbed methane (CBM). The modification and antireflection of pore and fracture in coal reservoir through ultrahigh and ultralow temperature stress, such as liquid nitrogen frozen-induced cracking and thermal antireflection of coal reservoir, have attracted wide research attention. This study conducted a nuclear magnetic resonance (NMR) experiment of pore and fracture features of coal samples under two extreme temperatures (100°C, −196°C) using the Meso MR23-060H-I low-field NMR and imaging instrument. The influencing law of ultrahigh and ultralow temperature stress on pore and fracture development in high-rank coal was discussed. Results demonstrated that temperature can influence pore and fracture development of high-rank coal samples. The pore volume, porosity, and permeability of the coal sample increase after low-temperature (−196°C) treatment. The proportion of microspores decreases, the proportion of small pores increases, the proportion of mesopores remains the same, and the proportion of macrospores increases to some extent. The pore volume of coal sample decreases after high-temperature (100°C) treatment. Porosity and permeability decrease. The proportion of mesopores declines, the proportion of mesopores remains basically same, and the proportion of macrospores decreases.

scholarly journals Analysis and control of flow at suction connection in high-speed centrifugal pump

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668529 ◽  
Author(s):  
Wen-wu Song ◽  
Li-chao Wei ◽  
Jie Fu ◽  
Jian-wei Shi ◽  
Xiu-xin Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
High Speed ◽  
Internal Flow ◽  
Orifice Plate ◽  
Centrifugal Pumps ◽  
Pressure Area ◽  
Negative Effect ◽  
And Control ◽  
Experimental Data Analysis

The backflow vortexes at the suction connection in high-speed centrifugal pumps have negative effect on the flow field. Setting an orifice plate in front of the inducer is able to decrease the negative effect caused by backflow vortexes. The traditional plate is able to partially control the backflow vortexes, but a small part of the vortex is still in the inlet and the inducer. Four new types of orifice plates were created, and the control effects on backflow vortexes were analyzed. The ANSYS-CFX software was used to numerically simulate a high-speed centrifugal pump. The variations of streamline and velocity vectors at the suction connection were analyzed. Meanwhile, the effects of these plates on the impeller pressure and the internal flow field of the inducer were analyzed. Numerically, simulation and experimental data analysis methods were used to compare the head and efficiency of the high-speed pumps. The results show that the C-type orifice plate can improve the backflow vortex, reduce the low-pressure area, and improve the hydraulic performance of the high-speed pump.

Sign in / Sign up

Export Citation Format

Share Document