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Full-Text Articles in Engineering
In-Field Jc Improvement By Oxygen-Free Pyrene Gas Diffusion Into Highly Dense Mgb2 Superconductor, Minoru Maeda, Jung Ho Kim, Y Zhao, Yoon-Uk Heo, K Takase, Y Kubota, C Moriyoshi, F Yoshida, Y Kuroiwa, S X. Dou
In-Field Jc Improvement By Oxygen-Free Pyrene Gas Diffusion Into Highly Dense Mgb2 Superconductor, Minoru Maeda, Jung Ho Kim, Y Zhao, Yoon-Uk Heo, K Takase, Y Kubota, C Moriyoshi, F Yoshida, Y Kuroiwa, S X. Dou
Australian Institute for Innovative Materials - Papers
Oxygen-free pyrene gas as a carbon (C) dopant was delinked and incorporated into highly dense MgB2 structure via a gas phase diffusion method. The technique offers the advantages that molecular C is homogeneously distributed into MgB2 and substituted at the boron sites without any severe deterioration of grain connectivity. The C substitution causes a significant shrinkage of the a-lattice parameter and an increase in the lattice strain, resulting in high disorder. The introduction of structural disorder as a result of C doping leads to a considerable enhancement of the in-field critical current density (Jc) and upper critical …
Influence Of Temperature On The Gas Content Of Coal And Sorption Modelling, Lei Zhang, Najdat I. Aziz, Ting Ren, Zhongwei Wang
Influence Of Temperature On The Gas Content Of Coal And Sorption Modelling, Lei Zhang, Najdat I. Aziz, Ting Ren, Zhongwei Wang
Faculty of Engineering - Papers (Archive)
n experimental study was undertaken to examine the sorption and desorption characteristics of coal at temperatures of 35 °C, 45 °C and 55 °C. The study focused on the effect of changes in temperature and coal particle sizes on gas sorption and desorption characteristics. The coal size used ranged from fragmented coals, 16 mm, 8 mm, 2.4 mm, powdered coal of 150 μm and 54 mm core samples. The samples were tested in pressure vessels, known as bombs, and charged with CO2 gas at different pressure levels up to a maximum of 4000 kPa. It was found that temperature was …
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) …
The Influence Of Copper Content Of Welding Wires On The Fume Formation Rates In Gas Metal Arc Welding Of Steel, N Bothma, B J. Monaghan, J Norrish
The Influence Of Copper Content Of Welding Wires On The Fume Formation Rates In Gas Metal Arc Welding Of Steel, N Bothma, B J. Monaghan, J Norrish
Faculty of Engineering - Papers (Archive)
Increases in Fume Formation Rates (FFR) of welding wires have been attributed to the fact that wires are copper coated. Instability during the welding process can have an influence on the FFR. The University of Wollongong has developed an auto control mechanism that will minimise the influence of the instability and this could be applied to more accurately determine the FFR of welding wires in the "drop-spray" mode of transfer.
Actions To Improve Coal Seam Gas Drainage Performance, Dennis Black, Najdat I. Aziz
Actions To Improve Coal Seam Gas Drainage Performance, Dennis Black, Najdat I. Aziz
Faculty of Engineering - Papers (Archive)
Coal seam gas drainage is affected by many factors which may be generally divided into two groups, geological factors and operational factors. Studies conducted in the Bulli seam found geological factors had a dominant impact on coal seam gas drainage while operational factors had a secondary impact, affecting the amount of optimum gas drainage performance achieved within the limitations imposed by the prevailing geological conditions. Various operational factors, which are controllable by the mine operator and which have a significant impact on gas drainage effectiveness, are presented and recommendations made to improve and optimise gas drainage performance.
Mine Gas Drainage And Outburst Control In Australian Underground Coal Mines, Najdat I. Aziz, Dennis Black, Ting Ren
Mine Gas Drainage And Outburst Control In Australian Underground Coal Mines, Najdat I. Aziz, Dennis Black, Ting Ren
Faculty of Engineering - Papers (Archive)
Australia produces both black and brown coal and is the world's fourth largest producer of black coal, after China, USA and India. Australian underground coal mines operate under controlled safety codes. The establishment of the mine safety management system, including the 1994 outburst management plan, contributed to a significant improvement in mine safety leading to non-fatality in outburst related incidences since 1994. The management of outburst risk, as a part of the overall safety and health management system is described. Also discussed are the introduction of outburst threshold limit values and the desorption rate index which forms the basis for …
Review Of Gas Emission Prediction And Control Methods For Multi-Seam Mining In Chinese Coal Mines, Zhongwei Wang, Ting Ren, Lei Zhang
Review Of Gas Emission Prediction And Control Methods For Multi-Seam Mining In Chinese Coal Mines, Zhongwei Wang, Ting Ren, Lei Zhang
Faculty of Engineering - Papers (Archive)
In China, the practice of multi-seam mining with high gas emission rates is common, and many coal mines are suffering from major gas management issues. To deal with these problems, empirical formulas for gas emission prediction and gas control methods suitable for site-specific conditions are developed. Specifically, the statistical method and split–source-method are widely used for gas emission prediction. In addition to ventilation, various gas control methods, including cross-measure boreholes, directional long-holes, dedicated roadways and surface goaf wells are used for gas drainage. Techniques for integrated extraction of coal and coal seam gas have been developed in these coal mines, …
Advanced Directional Drilling Technology For Gas Drainage And Exploration In Australian Coal Mines, Fangtian Wang, Ting Ren, Frank Hungerford, Shihao Tu, Najdat I. Aziz
Advanced Directional Drilling Technology For Gas Drainage And Exploration In Australian Coal Mines, Fangtian Wang, Ting Ren, Frank Hungerford, Shihao Tu, Najdat I. Aziz
Faculty of Engineering - Papers (Archive)
With the continuing technology innovation, directional drilling technology has provided the coal mining industry with effective and practical options for pre- and post-drainage and exploration in Australia. In the past thirty years, in-mine borehole steering equipment has been developed from the single shot camera survey systems to the advanced Directional Drill Monitor utilizing Modular Electrically Connected Cable Assembly (DDM-MECCA) survey instruments, which provides rapid and easy underground borehole survey measurements whilst drilling. The presence of coal seam gas such as methane poses a significant safety hazard to underground coal mining all over the world. However, gas can be captured using …
Self-Assembly Of [1010] Grown Zno Nanowhiskers With Exposed Reactive (0001) Facets On Hollow Spheres And Their Enhanced Gas Sensitivity, Jun Liu, Xiaolong Chen, Wenjun Wang, Yu Liu, Qingsong Huang, Zaiping Guo
Self-Assembly Of [1010] Grown Zno Nanowhiskers With Exposed Reactive (0001) Facets On Hollow Spheres And Their Enhanced Gas Sensitivity, Jun Liu, Xiaolong Chen, Wenjun Wang, Yu Liu, Qingsong Huang, Zaiping Guo
Faculty of Engineering - Papers (Archive)
In this work, we demonstrate a simple gas-phase process to synthesize ZnO with exposed reactive {0001} facets without the use of any capping agent. The method is based on controlling the ZnO growth direction, causing it to switch from the typical [0001] to [100], resulting in [100] grown nanowhiskers with exposed reactive {0001} facets. Moreover, these nanowhiskers self-assemble on ZnO hollow spheres to form a three-dimensional hierarchical nanostructure, which stabilizes these nanowhiskers against agglomeration. Such a designed ZnO nanostructure endows the ZnO sensing material with both small crystal sizes and exposed reactive {0001} facets, which leads to greatly enhanced gas …