The Outburst Risk as a Function of the Methane Capacity and Firmness of a Coal Seam

2014 ◽  
Vol 59 (4) ◽  
pp. 1023-1031 ◽  
Author(s):  
Mirosław Wierzbicki ◽  
Norbert Skoczylas

Abstract In most coal basins that are currently being exploited, gas and rock outbursts pose a considerable safety threat. The risk of their occurrence is frequently assessed by means of a parameter known as the methane capacity of coal. In a lot of countries, the evaluation of the mechanical properties of coal is conducted by means of another parameter: the firmness of coal. Due to the laboratory investigations and in situ observations carried out by the authors of this paper, it was possible to determine a function space in which the outburst risk can be described as a function of the methane capacity and firmness of a coal seam. This, in turn, made it possible to link the „gas factor” to the „mechanical factor”, and thus provide a more comprehensive risk analysis.

1977 ◽  
Vol 13 (5) ◽  
pp. 521-525
Author(s):  
V. K. Aksenov ◽  
G. S. Kuzin ◽  
M. V. Kurlenya ◽  
L. P. Tomashevskii

2013 ◽  
Vol 58 (1) ◽  
pp. 145-157
Author(s):  
E. Bakhtavar ◽  
K. Shahriar

Obtaining the maximum productivity with minimum energy consumption in coaling faces, directly depends on selection of the suitable shearer loader machine with the most effective and fitness picks for it and also their arrangement on cutter head. In order to select appropriate shearer loader machine, some in-situ tests have been carried out on C1 coal seam of Parvadeh1 long wall mine located in east of Iran. Studying of the mechanical properties of C1 coal seam demonstrates an extremely low strength of coal. Thus, it was concluded that a kind of two drums shearer (model EL600) with the conical picks can be effectively worked.


Author(s):  
T. Marieb ◽  
J. C. Bravman ◽  
P. Flinn ◽  
D. Gardner ◽  
M. Madden

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].


2003 ◽  
Vol 778 ◽  
Author(s):  
Rajdip Bandyopadhyaya ◽  
Weizhi Rong ◽  
Yong J. Suh ◽  
Sheldon K. Friedlander

AbstractCarbon black in the form of nanoparticle chains is used as a reinforcing filler in elastomers. However, the dynamics of the filler particles under tension and their role in the improvement of the mechanical properties of rubber are not well understood. We have studied experimentally the dynamics of isolated nanoparticle chain aggregates (NCAs) of carbon made by laser ablation, and also that of carbon black embedded in a polymer film. In situ studies of stretching and contraction of such chains in the transmission electron microscope (TEM) were conducted under different maximum values of strain. Stretching causes initially folded NCA to reorganize into a straight, taut configuration. Further stretching leads to either plastic deformation and breakage (at 37.4% strain) or to a partial elastic behavior of the chain at small strains (e.g. 2.3% strain). For all cases the chains were very flexible under tension. Similar reorientation and stretching was observed for carbon black chains embedded in a polymer film. Such flexible and elastic nature of NCAs point towards a possible mechanism of reinforcement of rubber by carbon black fillers.


2018 ◽  
Vol 60 (12) ◽  
pp. 1221-1224 ◽  
Author(s):  
Balachandran Gobalakrishnan ◽  
P. Ramadoss Lakshminarayanan ◽  
Raju Varahamoorthi

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