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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

The Spatial and Temporal Distribution of the Metal Mineralisation in Eastern Australia and the Relationship of the Observed Patterns to Giant Ore Deposits

Robinson, Larry J. Unknown Date (has links)
The introduced mineral deposit model (MDM) is the product of a trans-disciplinary study, based on Complexity and General Systems Theory. Both investigate the abstract organization of phenomena, independent of their substance, type, or spatial or temporal scale of existence. The focus of the research has been on giant, hydrothermal mineral deposits. They constitute <0.001% of the total number of deposits yet contain 70-85% of the world's metal resources. Giants are the definitive exploration targets. They are more profitable to exploit and less susceptible to fluctuations of the market. Consensus has it that the same processes that generate small deposits also form giants but those processes are simply longer, vaster, and larger. Heat is the dominant factor in the genesis of giant mineral deposits. A paleothermal map shows where the vast heat required to generate a giant has been concentrated in a large space, and even allows us to deduce the duration of the process. To generate a paleothermal map acceptable to the scientific community requires reproducibility. Experimentation with various approaches to pattern recognition of geochemical data showed that the AUTOCLUST algorithm not only gave reproducibility but also gave the most consistent, most meaningful results. It automatically extracts boundaries based on Voronoi and Delaunay tessellations. The user does not specify parameters; however, the modeller does have tools to explore the data. This approach is near ideal in that it removes much of the human-generated bias. This algorithm reveals the radial, spatial distribution, of gold deposits in the Lachlan Fold Belt of southeastern Australia at two distinct scales – repeating patterns every ~80 km and ~230 km. Both scales of patterning are reflected in the geology. The ~80 km patterns are nested within the ~230 km patterns revealing a self-similar, geometrical relationship. It is proposed that these patterns originate from Rayleigh-Bénard convection in the mantle. At the Rayleigh Number appropriate for the mantle, the stable planform is the spoke pattern, where hot mantle material is moving upward near the centre of the pattern and outward along the radial arms. Discontinuities in the mantle, Rayleigh-Bénard convection in the mantle, and the spatial distribution of giant mineral deposits, are correlative. The discontinuities in the Earth are acting as platforms from which Rayleigh-Bénard convection can originate. Shallow discontinuities give rise to plumelets, which manifest at the crust as repeating patterns ranging, from ~100 to ~1,000 km in diameter. Deeper discontinuities give rise to plumes, which become apparent at the crust as repeating patterns ranging from >1,000 to ~4,000 km in diameter. The deepest discontinuities give rise to the superplumes, which become detectable at the crust as repeating patterns ranging from >4,000 to >10,000 km in diameter. Rayleigh-Bénard convection concentrates the reservoir of heat in the mantle into specific locations in the crust; thereby providing the vast heat requirements for the processes that generate giant, hydrothermal mineral deposits. The radial spatial distribution patterns observed for gold deposits are also present for base metal deposits. At the supergiant Broken Hill deposit in far western New South Wales, Australia, the higher temperature Broken Hill-type deposits occur in a radial pattern while the lower temperature deposits occur in concentric patterns. The supergiant Broken Hill deposit occurs at the very centre of the pattern. If the supergiant Broken Hill Deposit was buried beneath alluvium, water or younger rocks, it would now be possible to predict its location with accuracy measured in tens of square kilometres. This predictive accuracy is desired by every exploration manager of every exploration company. The giant deposits at Broken Hill, Olympic Dam, and Mount Isa all occur on the edge of an annulus. There are at least two ways of creating an annulus on the Earth's surface. One is through Rayleigh-Bénard convection and the other is through meteor impact. It is likely that only 'large' meteors (those >10 km in diameter) would have any permanent impact on the mantle. Lesser meteors would leave only a superficial scar that would be eroded away. The permanent scars in the mantle act as ‘accidental templates’ consisting of concentric and possibly radial fractures that impose those structures on any rocks that were subsequently laid down or emplaced over the mantle. In southeastern Australia, the proposed Deniliquin Impact structure has been an 'accidental template' providing a 'line-of-least-resistance' for the ascent of the ~2,000 km diameter, offshore, Cape Howe Plume. The western and northwestern radial arms of this plume have created the very geometry of the Lachlan Fold Belt, as well as giving rise to the spatial distribution of the granitic rocks in that belt and ultimately to the gold deposits. The interplay between the templating of the mantle by meteor impacts and the ascent of plumelets, plumes or superplumes from various discontinuities in the mantle is quite possibly the reason that mineral deposits occur where they do.
142

The Spatial and Temporal Distribution of the Metal Mineralisation in Eastern Australia and the Relationship of the Observed Patterns to Giant Ore Deposits

Robinson, Larry J. Unknown Date (has links)
The introduced mineral deposit model (MDM) is the product of a trans-disciplinary study, based on Complexity and General Systems Theory. Both investigate the abstract organization of phenomena, independent of their substance, type, or spatial or temporal scale of existence. The focus of the research has been on giant, hydrothermal mineral deposits. They constitute <0.001% of the total number of deposits yet contain 70-85% of the world's metal resources. Giants are the definitive exploration targets. They are more profitable to exploit and less susceptible to fluctuations of the market. Consensus has it that the same processes that generate small deposits also form giants but those processes are simply longer, vaster, and larger. Heat is the dominant factor in the genesis of giant mineral deposits. A paleothermal map shows where the vast heat required to generate a giant has been concentrated in a large space, and even allows us to deduce the duration of the process. To generate a paleothermal map acceptable to the scientific community requires reproducibility. Experimentation with various approaches to pattern recognition of geochemical data showed that the AUTOCLUST algorithm not only gave reproducibility but also gave the most consistent, most meaningful results. It automatically extracts boundaries based on Voronoi and Delaunay tessellations. The user does not specify parameters; however, the modeller does have tools to explore the data. This approach is near ideal in that it removes much of the human-generated bias. This algorithm reveals the radial, spatial distribution, of gold deposits in the Lachlan Fold Belt of southeastern Australia at two distinct scales – repeating patterns every ~80 km and ~230 km. Both scales of patterning are reflected in the geology. The ~80 km patterns are nested within the ~230 km patterns revealing a self-similar, geometrical relationship. It is proposed that these patterns originate from Rayleigh-Bénard convection in the mantle. At the Rayleigh Number appropriate for the mantle, the stable planform is the spoke pattern, where hot mantle material is moving upward near the centre of the pattern and outward along the radial arms. Discontinuities in the mantle, Rayleigh-Bénard convection in the mantle, and the spatial distribution of giant mineral deposits, are correlative. The discontinuities in the Earth are acting as platforms from which Rayleigh-Bénard convection can originate. Shallow discontinuities give rise to plumelets, which manifest at the crust as repeating patterns ranging, from ~100 to ~1,000 km in diameter. Deeper discontinuities give rise to plumes, which become apparent at the crust as repeating patterns ranging from >1,000 to ~4,000 km in diameter. The deepest discontinuities give rise to the superplumes, which become detectable at the crust as repeating patterns ranging from >4,000 to >10,000 km in diameter. Rayleigh-Bénard convection concentrates the reservoir of heat in the mantle into specific locations in the crust; thereby providing the vast heat requirements for the processes that generate giant, hydrothermal mineral deposits. The radial spatial distribution patterns observed for gold deposits are also present for base metal deposits. At the supergiant Broken Hill deposit in far western New South Wales, Australia, the higher temperature Broken Hill-type deposits occur in a radial pattern while the lower temperature deposits occur in concentric patterns. The supergiant Broken Hill deposit occurs at the very centre of the pattern. If the supergiant Broken Hill Deposit was buried beneath alluvium, water or younger rocks, it would now be possible to predict its location with accuracy measured in tens of square kilometres. This predictive accuracy is desired by every exploration manager of every exploration company. The giant deposits at Broken Hill, Olympic Dam, and Mount Isa all occur on the edge of an annulus. There are at least two ways of creating an annulus on the Earth's surface. One is through Rayleigh-Bénard convection and the other is through meteor impact. It is likely that only 'large' meteors (those >10 km in diameter) would have any permanent impact on the mantle. Lesser meteors would leave only a superficial scar that would be eroded away. The permanent scars in the mantle act as ‘accidental templates’ consisting of concentric and possibly radial fractures that impose those structures on any rocks that were subsequently laid down or emplaced over the mantle. In southeastern Australia, the proposed Deniliquin Impact structure has been an 'accidental template' providing a 'line-of-least-resistance' for the ascent of the ~2,000 km diameter, offshore, Cape Howe Plume. The western and northwestern radial arms of this plume have created the very geometry of the Lachlan Fold Belt, as well as giving rise to the spatial distribution of the granitic rocks in that belt and ultimately to the gold deposits. The interplay between the templating of the mantle by meteor impacts and the ascent of plumelets, plumes or superplumes from various discontinuities in the mantle is quite possibly the reason that mineral deposits occur where they do.
143

Problematika poskytování auditorských služeb v České republice u malých auditorských praxí / Focus on Audit Services in the Czech Republic in the Selected Small Audit Companies

Uminská, Karolína January 2018 (has links)
In this thesis I deal with the analysis of current problems on the market of auditing services in the Czech Republic, with suggestions for their solution. The theoretical part contents analysis of the historical context of the audit, the legal regulation, e. g. International Standards on Auditing (ISAs), Czech Act on Auditors and link to other laws. This part also contents analysis of the market of auditing services focusing on small auditing companies and also description on problems connected with entering the audit profession and consequently the problems related to market regulation, evaluation and quality control of the provided auditing services. Case studies in the practical part reflects the most important problems of small auditing companies. This will be complemented by a questionnaire survey that should reveal the different points of view of the audited company, accountant and auditor on key audit issues.
144

Investigating The Universality And Comprehensive Ability Of Measures To Assess The State Of Workload

Abich, Julian 01 January 2013 (has links)
Measures of workload have been developed on the basis of the various definitions, some are designed to capture the multi-dimensional aspects of a unitary resource pool (Kahneman, 1973) while others are developed on the basis of multiple resource theory (Wickens, 2002). Although many theory based workload measures exist, others have often been constructed to serve the purpose of specific experimental tasks. As a result, it is likely that not every workload measure is reliable and valid for all tasks, much less each domain. To date, no single measure, systematically tested across experimental tasks, domains, and other measures is considered a universal measure of workload. Most researchers would argue that multiple measures from various categories should be applied to a given task to comprehensively assess workload. The goal for Study 1 to establish task load manipulations for two theoretically different tasks that induce distinct levels of workload assessed by both subjective and performance measures was successful. The results of the subjective responses support standardization and validation of the tasks and demands of that task for investigating workload. After investigating the use of subjective and objective measures of workload to identify a universal and comprehensive measure or set of measures, based on Study 2, it can only be concluded that not one or a set of measures exists. Arguably, it is not to say that one will never be conceived and developed, but at this time, one does not reside in the psychometric catalog. Instead, it appears that a more suitable approach is to customize a set of workload measures based on the task. The novel approach of assessing the sensitivity and comprehensive ability of conjointly utilizing subjective, performance, and physiological workload measures for theoretically different tasks within the same domain contributes to the theory by laying the foundation for improving methodology for researching workload. The applicable contribution of this project is a stepping-stone towards developing complex profiles of workload for use in closed-loop systems, such as human-robot team iv interaction. Identifying the best combination of workload measures enables human factors practitioners, trainers, and task designers to improve methodology and evaluation of system designs, training requirements, and personnel selection

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