41 resultados para Diamond mines and mining


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Water management is a matter of global concern. To underpin sound management of water scarcity and quality issues requires high quality, consistent, understandable and credible information. In a world first, accounting and water industry experts in Australia have developed a system of water accounting as an accounting sub-discipline, analogous to financial accounting to guide national and intra-national decision-making. With a conceptual framework and a Preliminary Australian Water Accounting Standard in place, Australia’s approach is being evaluated internationally within the water and mining industries. Its fate as a discipline will depend upon regulatory politics as well as the intellectual and practical rigour of the system and the rate of its adoption. In this paper, we explore the application to water accounting of regulatory theories that have been valuable to gaining an understanding of financial accounting standards development. We predict the international path of the water accounting a sub-discipline of accounting, as an outcome of political forces.

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Based on the behaviour of the superplastic deformation of metallic glasses and Pilling’s model, a diffusion bonding model suitable for metallic glasses is proposed in the present study. In the current model, the diffusion bonding processes consists of two stages: one is the plastic deformation stage and the other is the void shrinkage stage, in which, the atom diffusion and superplastic deformation are responsible for the void shrinkage. Applying this model to the diffusion bonding of a Zr based metallic glass, the predicted bonding time is in good agreement with the experimental result. A map for determining the bonding temperature and time to achieve high quality bonding in a Zr based metallic glass is suggested.

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This paper explores first-day returns on infrastructure entity initial public offerings (IPOs) in Australia from 1996 to 2007. While a good deal has been written on the first-day returns of industrial and mining company IPOs and Real Estate Investment Trust IPOs, first-day returns of infrastructure entity IPOs have yet to be reported in the literature. The study uses ordinary least squares regression analysis to identify factors that might influence the percentage first-day returns theoretically available to investing subscribers and factors that might influence the aggregate amount of money left to subscribers by issuers. The study finds that first-day returns, on average, are not significantly different from zero. There is evidence, however, that suggests higher dividend yields and higher percentage direct costs of capital raising influence these first-day returns. The study also finds that infrastructure entity IPOs that seek to raise more equity capital leave less money on the table for subscribing investors.

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Eighteen protic ionic liquids containing different combinations of cations and anions, hydrophobicity, viscosity, and conductivity have been synthesized and their physicochemical properties determined. In one series, the diethanolammonium cations were combined with acetate, formate, hydrogen sulfate, chloride, sulfamate, and mesylate anions. In the second series, acetate and formate anions were combined with amine bases, triethylamine, diethylamine, triethanolamine, di-n-propylamine, and di-n-butylamine. The electrochemical characteristics of the eight protic ionic liquids that are liquid at room temperature (RTPILs) have been determined using cyclic, microelectrode, and rotating disk electrode voltammetries. Potential windows of the RTPILs have been compared at glassy carbon, platinum, gold, and boron-doped diamond electrodes and generally found to be the largest in the case of glassy carbon. The voltammetry of IUPAC recommended potential scale reference systems, ferrocene/ferrocenium and cobaltocenium/cobaltocene, have been evaluated and found to be ideal in the case of the less viscous RTPILs but involve adsorption in the highly viscous ones. Other properties such as diffusion coefficients, ionic conductivity, and double layer capacitance also have been measured. The influence of water on the potential windows, viscosity, and diffusion has been studied systematically by deliberate addition of water to the dried ionic liquids. The survey highlights the problems with voltammetric studies in highly viscous room temperature protic ionic liquids and also suggests the way forward with respect to their possible industrial use.

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The microstructure-property relationship in conventional high strength low alloy (HSLA) steel was evaluated using data obtained from transmission electron microscopy (TEM) and atom probe tomography (APT). Atom probe tomography allowed the characterisation of fine TiC particles with average radius of 3±1·2 nm that were not observed by TEM. The increase in the yield strength of steel due to the presence of fine precipitates was calculated to be 128 MPa.

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Differential privacy is a strong definition for protecting individual privacy in data releasing and mining. However, it is a rigid definition introducing a large amount of noise to the original dataset, which significantly decreases the quality of data mining results. Recently, how to design a suitable data releasing algorithm for data mining purpose is a hot research area. In this paper, we propose a differential private data releasing algorithm for decision tree construction. The proposed algorithm provides a non-interactive data releasing method through which miner can obtain the complete dataset for data mining purpose. With a given privacy budget, the proposed algorithm generalizes the original dataset, and then specializes it in a differential privacy constrain to construct decision trees. As the designed novel scheme selection operation can fully utilize the allocated privacy budget, the data set released by the proposed algorithm can yield better decision tree models than other method. Experimental results demonstrate that the proposed algorithm outperforms existing methods for private decision tree construction.

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The Mineral and Petroleum Resources Development Act 28 of 2002 (ZA) (MPRDA) makes provision for the conversion of so-called “old order” rights to prospecting and mining rights. The consequences of the failure of holders of old order rights to apply for (a) Conversion or (b) new rights under different circumstances were decided by the South African Constitutional Court in two decisions during 2013. These cases are discussed against the background of the nature, content and termination of old order rights. It is also discussed whether such rights were expropriated by the MPRDA and, if so, whether compensation is payable by the state.

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Rare earth organic compounds can provide an environmentally safe and non-toxic alternative to chromates as corrosion inhibitors for some steel and aluminium applications. For steel lanthanum 4-hydroxy cinnamate offers corrosion protection and reduces the susceptibility to hydrogen embrittlement. Recent work has also indicated that it inhibits the corrosion of steel in environments containing high levels of carbon dioxide. For aluminium alloys, cerium diphenyl phosphate provides excellent corrosion inhibition in chloride environments, and reduces susceptibly to stress corrosion cracking. Furthermore, for both steel and aluminium alloys filiform corrosion can be suppressed when rare earth inhibitor compounds are added as pigments to polymer coatings. The levels of inhibition observed are thought to be due to synergistic effects between the rare earth and organic parts of these novel compounds, and are related to the various species that may be present in the complex chemical conditions that develop in solution close to a metal surface. This paper reviews some of the published research conducted by the group at Deakin University over recent years.©2014 Institute of Materials, Minerals and Mining.

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The present paper reviews recent progress in atomic-scale characterisation of composition and nanostructure of light alloy materials using the technique of atom probe tomography. In particular, the present review will highlight atom-by-atom analysis of solid solution architecture, including solute clustering and short-range order, with reference to current limitations of spatial resolution and detector efficiency of atom probe tomography and methods to address these limitations. This leads to discussion of prediction of mechanical properties by simulation and modelling of the strengthening effect exerted by solute clusters and the role of experimental atom probe data to assist in this process. The unique contribution of atom probe tomography to the study of corrosion and hydrogen embrittlement of light alloys will also be discussed as well as a brief insight into its potential application for the investigation of solute strengthening of twinning in Mg alloys.

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© 2015 Institute of Materials, Minerals and Mining. Published by Maney on behalf of the Institute. This paper describes an interesting attempt to quantitatively evaluate the corrosion behaviour of base oils using a novel approach based on electrochemical techniques. The present study evaluates the corrosion behaviour of biodegradable base oils with and without additives in an aqueous chloride solution using electrochemical measurements. Potentiodynamic polarisation and electrochemical impedance spectroscopy techniques were used to quantitatively determine the corrosion behaviour of these oils, and the results were compared to the conventional immersion tests. Both these electrochemical measurements were carried out in a three-electrode system where AS1020 mild steel alloy was used as a working electrode in a purpose made pipette cell. The results obtained from the electrochemical measurements help to evaluate the best biodegradable base oil for formulating eco-friendly industrial lubricants.