945 resultados para ore deposit
Resumo:
Plasma enhanced chemical vapour deposition silicon nitride thin films are widely used in microelectromechanical system devices as structural materials because the mechanical properties of those films can be tailored by adjusting deposition conditions. However, accurate measurement of the mechanical properties, such as hardness, of films with thicknesses at nanometric scale is challenging. In the present study, the hardness of the silicon nitride films deposited on silicon substrate under different deposit conditions was characterised using nanoindentation and nanoscratch deconvolution methods. The hardness values obtained from the two methods were compared. The effect of substrate on the measured results was discussed.
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During a major flood event, the inundation of urban environments leads to some complicated flow motion most often associated with significant sediment fluxes. In the present study, a series of field measurements were conducted in an inundated section of the City of Brisbane (Australia) about the peak of a major flood in January 2011. Some experiments were performed to use ADV backscatter amplitude as a surrogate estimate of the suspended sediment concentration (SSC) during the flood event. The flood water deposit samples were predominantly silty material with a median particle size about 25 μm and they exhibited a non-Newtonian behavior under rheological testing. In the inundated urban environment during the flood, estimates of suspended sediment concentration presented a general trend with increasing SSC for decreasing water depth. The suspended sediment flux data showed some substantial sediment flux amplitudes consistent with the murky appearance of floodwaters. Altogether the results highlighted the large suspended sediment loads and fluctuations in the inundated urban setting associated possibly with a non-Newtonian behavior. During the receding flood, some unusual long-period oscillations were observed (periods about 18 min), although the cause of these oscillations remains unknown. The field deployment was conducted in challenging conditions highlighting a number of practical issues during a natural disaster.
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In this paper, we present WebPut, a prototype system that adopts a novel web-based approach to the data imputation problem. Towards this, Webput utilizes the available information in an incomplete database in conjunction with the data consistency principle. Moreover, WebPut extends effective Information Extraction (IE) methods for the purpose of formulating web search queries that are capable of effectively retrieving missing values with high accuracy. WebPut employs a confidence-based scheme that efficiently leverages our suite of data imputation queries to automatically select the most effective imputation query for each missing value. A greedy iterative algorithm is also proposed to schedule the imputation order of the different missing values in a database, and in turn the issuing of their corresponding imputation queries, for improving the accuracy and efficiency of WebPut. Experiments based on several real-world data collections demonstrate that WebPut outperforms existing approaches.
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Intracellular Flightless I (Flii), a gelsolin family member, has been found to have roles modulating actin regulation, transcriptional regulation and inflammation. In vivo Flii can regulate wound healing responses. We have recently shown that a pool of Flii is secreted by fibroblasts and macrophages, cells typically found in wounds, and its secretion can be upregulated upon wounding. We show that secreted Flii can bind to the bacterial cell wall component lipopolysaccharide and has the potential to regulate inflammation. We now show that secreted Flii is present in both acute and chronic wound fluid.
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The aftermath of the Queensland floods of January 2011 continues to be played out in the courts. The effect of the floods on such a large scale has awakened the use of some statutory provisions that have not previously been litigated .Section 64 of the Property Law Act 1974 (Qld) is such a section. A version of this provision appears as s 34 of the Sale of Land Act 1982 (Vic). Broadly speaking, these sections permit a buyer of a dwelling house which has been damaged or destroyed between contract and completion to rescind the contract and recover their deposit provided that the rescission notice is given prior to "the date of completion or possession". The Court of Appeal decision of Dunworth v Mirvac Queensland Pty Ltd [2011] QCA 200 appears to be the first litigation upon the application of the section since it came into force in 1975.
Resumo:
Nanoscale MgO powder was synthesized from magnesite ore by a wet chemical method. Acid dissolution was used to obtain a solution from which magnesium containing complexes were precipitated by either oxalic acid or ammonium hydroxide, The transformation of precipitates to the oxide was monitored by thermal analysis and XRD and the transformed powders were studied by electron microscopy. The MgO powders were added as dopants to Bi2SrCa2CuO8 powders and high temperature superconductor thick films were deposited on silver. Addition of suitable MgO powder resulted in increase of critical current density, J(c), from 8,900 Acm(-2) to 13,900 Acm(-2) measured at 77 K and 0 T. The effect of MgO addition was evaluated by XRD, electron microscopy and critical current density measurements. (C) 1998 Elsevier Science B.V.
Resumo:
Orebodies at Ok Tedi contain a number of different fluorine bearing minerals. Some of these minerals report to concentrate and are responsible for the presence of the penalty element, fluorine, within the concentrate. Previous analytical work has tended to examine geological samples for content, rather than determine the metallurgical behaviour of the different mineralogical species. This investigation utilised X-Ray Diffraction combined with Scanning Electron Microscope/Electron Microprobe to identify the fluorine bearing minerals in flotation test products. Seven fluorine bearing minerals were identified, viz., talc, phlogopite, amphibole (tremolite and actinolite), sphene, apatite, biotite and clay. Talc was found exclusively in the skarn ore type. Phlogopite and amphiboles (tremolite and actinolite) were found to occur in both skarn and porphyry ores, while sphene, apatite, biotite and clay were found only in the porphyry ores. Of the fluorine bearing minerals observed, only talc exhibited natural hydrophobicity to any significant degree. Phlogopite and the amphibole minerals were found to be hydrophillic, whilst the remaining minerals occurred in insufficient quantities to determine the flotation behaviour. Ok Tedi copper concentrate fluorine content prior to skarn ore treatment in the mill (typically 350ppm) was previously identified as deriving from phlogopite, while talc was believed to be the source of intermittent high concentrate fluorine contents when skarn ores were treated. This paper provides supporting evidence for this belief, and reports the nature of fluorine bearing mineral flotation behaviour.
Resumo:
QUT’s new metadata repository (data registry), Research Data Finder, has been designed to promote the visibility and discoverability of QUT research datasets. Funded by the Australian National Data Service (ANDS), it will provide a qualitative snapshot of research data outputs created or collected by members of the QUT research community that are available via open or mediated access. As a fully integrated metadata repository Research Data Finder aligns with institutional sources of truth, such as QUT’s research administrative system, ResearchMaster, as well as QUT’s Academic Profiles system to provide high quality data descriptions that increase awareness of, and access to, shareable research data. In addition, the repository and its workflows are designed to foster smoother data management practices, enhance opportunities for collaboration and research, promote cross-disciplinary research and maximize existing research datasets. The metadata schema used in Research Data Finder is the Registry Interchange Format - Collections and Services (RIF-CS), developed by ANDS in 2009. This comprehensive schema is potentially complex for researchers; unlike metadata for publications, which are often made publicly available with the official publication, metadata for datasets are not typically available and need to be created. Research Data Finder uses a hybrid self-deposit and mediated deposit system. In addition to automated ingests from ResearchMaster (research project information) and Academic Profiles system (researcher information), shareable data is identified at a number of key “trigger points” in the research cycle. These include: research grant proposals; ethics applications; Data Management Plans; Liaison Librarian data interviews; and thesis submissions. These ingested records can be supplemented with related metadata including links to related publications, such as those in QUT ePrints. Records deposited in Research Data Finder are harvested by ANDS and made available to a national and international audience via Research Data Australia, ANDS’ discovery service for Australian research data. Researcher and research group metadata records are also harvested by the National Library of Australia (NLA) and these records are then published in Trove (the NLA’s digital information portal). By contributing records to the national infrastructure, QUT data will become more visible. Within Australia and internationally, many funding bodies have already mandated the open access of publications produced from publicly funded research projects, such as those supported by the Australian Research Council (ARC), or the National Health and Medical Research Council (NHMRC). QUT will be well placed to respond to the rapidly evolving climate of research data management. This project is supported by the Australian National Data Service (ANDS). ANDS is supported by the Australian Government through the National Collaborative Research Infrastructure Strategy Program and the Education Investment Fund (EIF) Super Science Initiative.
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This contribution describes two mass movement deposits (total volume ~0.5 km3) identified in seven marine cores located 8 to 15 km offshore southern Montserrat, West Indies. The deposits were emplaced in the last 35 ka and have not previously been recognised in either the subaerial or distal submarine records. Age constraints, provided by radiocarbon dating, show that an explosive volcanic eruption occurred at ca 8–12 ka, emplacing a primary eruption-related deposit that overlies a large (~0.3 km3) reworked bioclastic and volcaniclastic flow deposit, formed from a shelf collapse between 8 and 35 ka. The origin of these deposits has been deduced through the correlation of marine sediment cores, component analysis and geochemical analysis. The 8–12 ka primary volcanic deposit was likely derived from a highly-erosive pyroclastic flow from the Soufrière Hills volcano that entered the ocean and mixed with the water column forming a water-supported density current. Previous investigations of the eruption record suggested that there was a hiatus in activity at the Soufrière Hills volcano between 16 and 6 ka. The ca 8–12 ka eruptive episode identified here shows that this hiatus was shorter than previously hypothesised, and thus highlights the importance of obtaining an accurate and completemarine record of events offshore from volcanic islands and incorporating such data into eruption history reconstructions. Comparisons with the submarine deposit characteristics of the 2003 dome collapse also suggests that the ~8–12 ka eruptive episode was more explosive than eruptions from the current eruptive episode.
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Catalytic CO2 reforming of biomass tar on palygorskite-supported nickel catalysts using toluene as a model compound of biomass tar was investigated. The experiments were performed in a bench scale installation a fixed bed reactor. All experiments were carried out at 650, 750, 800 °C and atmospheric pressure. The effect of Ni loading, reaction temperature and concentration of CO2 on H2 yield and carbon deposit was investigated. Ni/Palygorskite (Ni/PG) catalysts with Ni/PG ratios of 0%, 2%, 5% and 8% were tested, the last two show the best performance. H2 yield and carbon deposit diminished with the increase of reaction temperature, Ni loading, and CO2 concentration.
Strategies for gaining and maintaining academic support for the institutional open access repository
Resumo:
The impact of research can be measured by use or citation count. The more widely available that research outputs are; the more likely they are to be used, and the higher the impact. Making the author-manuscript version of research outputs freely available via the institutional repository greatly increases the availability of research outputs and can increase the impact. QUT ePrints, the open access institutional repository of research outputs at Queensland University of Technology (QUT), Australia, was established in 2003 and is managed by the QUT Library. The repository now contains over 39,000 records. More than 21,000 of these records have full-text copies attached as result of continuous effort to maintain momentum and encourage academic engagement. The full-text deposit rate has continued to increase over time and, in 2012 (August, at the time of writing), 88% of the records for works published in 2012 provide access to a full-text copy. Achieving success has required a long term approach to collaboration, open access advocacy, repository promotion, support for the deposit process, and ongoing system development. This paper discusses the various approaches adopted by QUT Library, in collaboration with other areas of the University, to achieve success. Approaches include mainstreaming the repository via having it report to the University Research and Innovation Committee; regular provision of deposit rate data to faculties; championing key academic supporters; and holding promotional competitions and events such as during Open Access Week. Support and training is provided via regular deposit workshops with academics and faculty research support groups and via the provision of online self-help information. Recent system developments have included the integration of citation data (from Scopus and Web of Science) and the development of a statistical reporting system which incentivise engagement.
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Analysis of fossils from cave deposits at Mount Etna (eastern-central Queensland) has established that a species-rich rainforest palaeoenvironment existed in that area during the middle Pleistocene. This unexpected finding has implications for several fields (e.g., biogeography/phylogeography of rainforest-adapted taxa, and the impact of climate change on rainforest communities), but it was unknown whether the Mount Etna sites represented a small refugial patch of rainforest or was more widespread. In this study numerous bone deposits in caves in north-east Queensland are analysed to reconstruct the environmental history of the area during the late Quaternary. Study sites are in the Chillagoe/Mitchell Palmer and Broken River/Christmas Creek areas. The cave fossil records in these study areas are compared with dated (middle Pleistocene-Holocene) cave sites in the Mount Etna area. Substantial taxonomic work on the Mount Etna faunas (particularly dasyurid marsupials and murine rodents) is also presented as a prerequisite for meaningful comparison with the study sites further north. Middle Pleistocene sites at Mount Etna contain species indicative of a rainforest palaeoenvironment. Small mammal assemblages in the Mount Etna rainforest sites (>500-280 ka) are unexpectedly diverse and composed almost entirely of new species. Included in the rainforest assemblages are lineages with no extant representatives in rainforest (e.g., Leggadina), one genus previously known only from New Guinea (Abeomelomys), and forms that appear to bridge gaps between related but morphologically-divergent extant taxa ('B-rat' and 'Pseudomys C'). Curiously, some taxa (e.g., Melomys spp.) are notable for their absence from the Mount Etna rainforest sites. After 280 ka the rainforest faunas are replaced by species adapted to open, dry habitats. At that time the extinct ‘rainforest’ dasyurids and rodents are replaced by species that are either extant or recently extant. By the late Pleistocene all ‘rainforest’ and several ‘dry’ taxa are locally or completely extinct, and the small mammal fauna resembles that found in the area today. The faunal/environmental changes recorded in the Mount Etna sites were interpreted by previous workers as the result of shifts in climate during the Pleistocene. Many samples from caves in the Chillagoe/Mitchell-Palmer and Broken River/Christmas Creek areas are held in the Queensland Museum’s collection. These, supplemented with additional samples collected in the field as well as samples supplied by other workers, were systematically and palaeoecologically analysed for the first time. Palaeoecological interpretation of the faunal assemblages in the sites suggests that they encompass a similar array of palaeoenvironments as the Mount Etna sites. ‘Rainforest’ sites at the Broken River are here interpreted as being of similar age to those at Mount Etna, suggesting the possibility of extensive rainforest coverage in eastern tropical Queensland during part of the Pleistocene. Likewise, faunas suggesting open, dry palaeoenvironments are found at Chillagoe, the Broken River and Mount Etna, and may be of similar age. The 'dry' faunal assemblage at Mount Etna (Elephant hole Cave) dates to 205-170 ka. Dating of one of the Chillagoe sites (QML1067) produced a maximum age for the deposit of approximately 200 ka, and the site is interpreted as being close to that age, supporting the interpretation of roughly contemporaneous deposition at Mount Etna and Chillagoe. Finally, study sites interpreted as being of late Pleistocene-Holocene age show faunal similarities to sites of that age near Mount Etna. This study has several important implications for the biogeography and phylogeography of murine rodents, and represents a major advance in the study of the Australian murine fossil record. Likewise the survey of the northern study areas is the first systematic analysis of multiple sites in those areas, and is thus a major contribution to knowledge of tropical Australian faunas during the Quaternary. This analysis suggests that climatic changes during the Pleistocene affected a large area of eastern tropical Queensland in similar ways. Further fieldwork and dating is required to properly analyse the geographical extent and timing of faunal change in eastern tropical Queensland.
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This project was a step forward in developing and evaluating a novel, mathematical model that can deduce the meaning of words based on their use in language. This model can be applied to a wide range of natural language applications, including the information seeking process most of us undertake on a daily basis.
Resumo:
This thesis examines the role of government as proprietor, preserver and user of copyright material under the Copyright Act 1968 (Cth) and the policy considerations which Australian law should take into account in that role. There are two recurring themes arising in this examination which are significant to the recommendations and conclusions. The first is whether the needs and status of government should be different from private sector institutions, which also obtain copyright protection under the law. This theme stems from the 2005 Report on Crown Copyright by the Copyright Law Review Committee and the earlier Ergas Committee Report which are discussed in Chapters 2 and 8 of this thesis. The second is to identify the relationship between government copyright law and policy, national cultural policy and fundamental governance values. This theme goes to the essence of the thesis. For example, does the law and practice of government copyright properly reflect technological change in the way we now access and use information and does it facilitate the modern information management principles of government? Is the law and practice of government copyright consistent with the greater openness and accountability of government? The thesis concludes that government copyright law and practice in each of the three governmental roles recognised under the Copyright Act 1968 has not responded adequately to the information age and to the desire and the ability of individuals to access information quickly and effectively. The solution offered in this thesis is reform of the law and of public policy that is in step with access to information policy, the promotion of better communication and interaction with the community, and the enhanced preservation of government and private copyright materials for reasons of government accountability, effective administration and national culture and heritage.
Resumo:
Mass flows on volcanic islands generated by volcanic lava dome collapse and by larger-volume flank collapse can be highly dangerous locally and may generate tsunamis that threaten a wider area. It is therefore important to understand their frequency, emplacement dynamics, and relationship to volcanic eruption cycles. The best record of mass flow on volcanic islands may be found offshore, where most material is deposited and where intervening hemipelagic sediment aids dating. Here we analyze what is arguably the most comprehensive sediment core data set collected offshore from a volcanic island. The cores are located southeast of Montserrat, on which the Soufriere Hills volcano has been erupting since 1995. The cores provide a record of mass flow events during the last 110 thousand years. Older mass flow deposits differ significantly from those generated by the repeated lava dome collapses observed since 1995. The oldest mass flow deposit originated through collapse of the basaltic South Soufriere Hills at 103-110 ka, some 20-30 ka after eruptions formed this volcanic center. A ∼1.8 km3 blocky debris avalanche deposit that extends from a chute in the island shelf records a particularly deep-seated failure. It likely formed from a collapse of almost equal amounts of volcanic edifice and coeval carbonate shelf, emplacing a mixed bioclastic-andesitic turbidite in a complex series of stages. This study illustrates how volcanic island growth and collapse involved extensive, large-volume submarine mass flows with highly variable composition. Runout turbidites indicate that mass flows are emplaced either in multiple stages or as single events.