scholarly journals Evolution Law of Overburden Longitudinal Connected Fissures in a Shallowly Buried Coal Face with Thin Bedrock

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Housheng Jia ◽  
Kun Pan ◽  
Luyao Wang ◽  
Shaowei Liu ◽  
Mengxiong Fu ◽  
...  
Keyword(s):  
Physical Simulation ◽  
Field Measurements ◽  
Water Inflow ◽  
Coal Face ◽  
Rock Falls ◽  
Holding Power ◽  
Abnormal Increase ◽  
Thin Bedrock ◽  
Main Factor

Longitudinal connected fissures in a shallowly buried coal face with thin bedrock are the main factor causing sand-burst accidents, water-burst accidents, and abnormal increases in water inflow. To understand the evolution of longitudinal connected fissures and propose method for controlling such fissures, 3-1 Coal of the Jinjie Coal Mine in Shendong Coal Group, China, was used as a case study. Physical simulation, numerical simulation, field measurements, and other measures were carried out to analyze thoroughly the opening and closure of fissures. At the same time, the stage characteristics of fissures evolution process are also obtained. The results indicate that when periodic weighting occurs, a longitudinal connected fissure starts to open. As the coal face moves on, the fissure expands gradually with the dynamic changes in horizontal force and rock dislocation; when the expansion reaches its limit, the key rock falls and the longitudinal connected fissure rapidly closes. With the advent of the next periodic weighting, the longitudinal connected fissure compacts further and the next longitudinal connected fissure appears. The formation of longitudinal connected fissures is described with reference to three factors: the advancement speed of the coal face, the holding power of the hydraulic support, and the filling degree of the goaf area, all of which can be easily controlled by engineering means. This study provides a basis for control of sand-burst accidents, water-burst accidents, and abnormal increase in water inflow in a shallow coal face with thin bedrock.

Energy Consumption Pattern of Residential Buildings: Case Study of Residential Area in Batu Pahat, Johor

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Junaidah Jailani ◽  
◽  
Norsyalifa Mohamad ◽  
Muhammad Amirul Omar ◽  
Hauashdh Ali ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Residential Buildings ◽  
Residential Area ◽  
Consumption Pattern ◽  
Air Conditioners ◽  
Residential Sector ◽  
Waste Energy ◽  
Main Factor ◽  
Energy Consumption Pattern

According to the National Energy Balance report released by the Energy Commission of Malaysia in 2016, the residential sector uses 21.6% of the total energy in Malaysia. Residents waste energy through inefficient energy consumption and a lack of awareness. Building occupants are considered the main factor that influences energy consumption in buildings, and to change energy consumption on an overall scale, it is crucial to change individual behaviour. Therefore, this study focused on analysing the energy consumption pattern and the behaviour of consumers towards energy consumption in their homes in the residential area of Batu Pahat, Johor. A self-administrated questionnaire approach was employed in this study. The findings of this study showed that the excessive use of air conditioners was a significant factor in the increasing electricity bills of homeowners as well as the inefficient use of electrical appliances. Also, this study determined the effect of awareness on consumer behaviour. This study recommends ways to help minimise energy consumption in the residential area.

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).

Mathematical and Physical Simulation of Indoor Daylighting: A Case Study

1997 ◽  
Vol 26 (3) ◽  
pp. 129-137
Author(s):  
S. R. Bandyopadhyay ◽  
Biswanath Ray
Keyword(s):  
Physical Simulation

Corrosion Metal Loss Interaction From In-Line Inspection and How it Can Affect the Calculated Failure Pressure

2012 ◽  
Author(s):  
Lucinda Smart ◽  
Richard McNealy ◽  
Harvey Haines
Keyword(s):  
Field Measurements ◽  
Metal Loss ◽  
Data Correlation ◽  
Failure Pressure ◽  
Industry Standards ◽  
Direct Measurements ◽  
Non Destructive ◽  
Flux Leakage

In-Line Inspection (ILI) is used to prioritize metal loss conditions based on predicted failure pressure in accordance with methods prescribed in industry standards such as ASME B31G-2009. Corrosion may occur in multiple areas of metal loss that interact and may result in a lower failure pressure than if flaws were analyzed separately. The B31G standard recommends a flaw interaction criterion for ILI metal loss predictions within a longitudinal and circumferential spacing of 3 times wall thickness, but cautions that methods employed for clustering of ILI anomalies should be validated with results from direct measurements in the ditch. Recent advances in non-destructive examination (NDE) and data correlation software have enabled reliable comparisons of ILI burst pressure predictions with the results from in-ditch examination. Data correlation using pattern matching algorithms allows the consideration of detection and reporting thresholds for both ILI and field measurements, and determination of error in the calculated failure pressure prediction attributable to the flaw interaction criterion. This paper presents a case study of magnetic flux leakage ILI failure pressure predictions compared with field results obtained during excavations. The effect of interaction criterion on calculated failure pressure and the probability of an ILI measurement underestimating failure pressure have been studied. We concluded a reason failure pressure specifications do not exist for ILI measurements is because of the variety of possible interaction criteria and data thresholds that can be employed, and demonstrate herein a method for their validation.

Soil respiration and N2O emission in croplands under different ploughing practices: a case study in south-east China

Soil Research ◽  
2009 ◽  
Vol 47 (2) ◽  
pp. 198 ◽  
Author(s):  
Shutao Chen ◽  
Yao Huang
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Agricultural Soils ◽  
Field Measurements ◽  
Triticum Aestivum L ◽  
N2o Emission ◽  
Cropping Season ◽  
Significant Difference

Studies on the CO2 and N2O emission patterns of agricultural soils under different ploughing practices may provide an insight into the potential and magnitude of CO2 and N2O mitigation in highly managed farmland soils. In this study, field measurements of soil respiration and N2O flux with different ploughing depths were performed in the 2003–04 wheat (Triticum aestivum L.), 2004 maize (Zea mays L.), and 2004–05 wheat seasons. Soil temperature and moisture were simultaneously measured. Results showed that, in each cropping season, the seasonal variation in soil respiration developed with a similar pattern for different treatments, which was primarily regulated by soil temperature. This work demonstrates that ploughing depth can influence long-term loss of carbon from soil, but this was contingent on preceding cropping types. Given the same preceding cropping practice, no significant difference in N2O emission was found among different ploughing depths in each cropping season.

scholarly journals Scattering of field-aligned beam ions upstream of Earth's bow shock

2007 ◽  
Vol 25 (3) ◽  
pp. 785-799 ◽  
Author(s):  
A. Kis ◽  
M. Scholer ◽  
B. Klecker ◽  
H. Kucharek ◽  
E. A. Lucek ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Measurements ◽  
Bow Shock ◽  
Ion Distribution ◽  
Parallel Side ◽  
Earth’S Bow Shock ◽  
High Mach ◽  
The Magnetic Field

Abstract. Field-aligned beams are known to originate from the quasi-perpendicular side of the Earth's bow shock, while the diffuse ion population consists of accelerated ions at the quasi-parallel side of the bow shock. The two distinct ion populations show typical characteristics in their velocity space distributions. By using particle and magnetic field measurements from one Cluster spacecraft we present a case study when the two ion populations are observed simultaneously in the foreshock region during a high Mach number, high solar wind velocity event. We present the spatial-temporal evolution of the field-aligned beam ion distribution in front of the Earth's bow shock, focusing on the processes in the deep foreshock region, i.e. on the quasi-parallel side. Our analysis demonstrates that the scattering of field-aligned beam (FAB) ions combined with convection by the solar wind results in the presence of lower-energy, toroidal gyrating ions at positions deeper in the foreshock region which are magnetically connected to the quasi-parallel bow shock. The gyrating ions are superposed onto a higher energy diffuse ion population. It is suggested that the toroidal gyrating ion population observed deep in the foreshock region has its origins in the FAB and that its characteristics are correlated with its distance from the FAB, but is independent on distance to the bow shock along the magnetic field.

scholarly journals “Veillant Panoptic Assemblage”: Mutual Watching and Resistance to Mass Surveillance after Snowden

2015 ◽  
Vol 3 (3) ◽  
pp. 12-25 ◽  
Author(s):  
Vian Bakir
Keyword(s):  
Journalism Studies ◽  
Holding Power ◽  
Digital Surveillance ◽  
The Press ◽  
Intelligence Agencies ◽  
State Surveillance ◽  
Intelligence Studies ◽  
Public Oversight

The Snowden leaks indicate the extent, nature, and means of contemporary mass digital surveillance of citizens by their intelligence agencies and the role of public oversight mechanisms in holding intelligence agencies to account. As such, they form a rich case study on the interactions of “veillance” (mutual watching) involving citizens, journalists, intelligence agencies and corporations. While Surveillance Studies, Intelligence Studies and Journalism Studies have little to say on surveillance of citizens’ data by intelligence agencies (and complicit surveillant corporations), they offer insights into the role of citizens and the press in holding power, and specifically the political-intelligence elite, to account. Attention to such public oversight mechanisms facilitates critical interrogation of issues of surveillant power, resistance and intelligence accountability. It directs attention to the <em>veillant panoptic assemblage</em> (an arrangement of profoundly unequal mutual watching, where citizens’ watching of self and others is, through corporate channels of data flow, fed back into state surveillance of citizens). Finally, it enables evaluation of post-Snowden steps taken towards achieving an <em>equiveillant panoptic assemblage</em> (where, alongside state and corporate surveillance of citizens, the intelligence-power elite, to ensure its accountability, faces robust scrutiny and action from wider civil society).

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