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Full-Text Articles in Engineering
Enhanced Gas Drainage From Undersaturated Coal Bed Methane Reservoirs, Dennis John Black, Naj Aziz, Ting Ren
Enhanced Gas Drainage From Undersaturated Coal Bed Methane Reservoirs, Dennis John Black, Naj Aziz, Ting Ren
Faculty of Engineering and Information Sciences - Papers: Part A
Traditional methods of coal seam gas drainage rely on the use of reservoir pressure reduction to promote gas desorption from the coal matrix. Studies in coal mining gas drainage operations, particularly in coal seams that are deeply undersaturated and have low permeability, found the rate of reservoir pressure reduction was prohibitively slow. In such conditions, lengthy production delays have been experienced while additional gas drainage drilling is undertaken in an attempt to reduce seam gas content below specified threshold limits. Such drilling represents a high additional operating cost and yields low total gas production whilst adversely impacting the mine's gas …
Post-Weld Atmospheric Contamination Of Gas Tungsten Arc Deposited Welds In Commercially Pure And Ti-6al-4v Titanium Alloys, Nicholas Hoye, Huijun Li, John Norrish, Rian Dippenaar
Post-Weld Atmospheric Contamination Of Gas Tungsten Arc Deposited Welds In Commercially Pure And Ti-6al-4v Titanium Alloys, Nicholas Hoye, Huijun Li, John Norrish, Rian Dippenaar
Faculty of Engineering and Information Sciences - Papers: Part A
Titanium alloys are known to exhibit unique weldability issues, particularly atmospheric contamination from interstitial species such as oxygen. The prevention of such impurities from entering the weld region and surrounding heat affected zones is critical for engineering applications as these species are seen to dramatically alter the microstructure and so mechanical properties of the material. Of greatest concern is embrittlement of the weld region. During this study, the influence of inert shielding gas on atmospheric contamination by interstitial species, namely hydrogen, carbon, nitrogen and oxygen, was investigated as a function of post-weld gas shielding temperature. Gas tungsten arc welding (GTAW) …