63 resultados para bubble attraction and coalescence

em Queensland University of Technology - ePrints Archive


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This paper is a deductive theoretical enquiry into the flow of effects from the geometry of price bubbles/busts, to price indices, to pricing behaviours of sellers and buyers, and back to price bubbles/busts. The intent of the analysis is to suggest analytical approaches to identify the presence, maturity, and/or sustainability of a price bubble. We present a pricing model to emulate market behaviour, including numeric examples and charts of the interaction of supply and demand. The model extends into dynamic market solutions myopic (single- and multi-period) backward looking rational expectations to demonstrate how buyers and sellers interact to affect supply and demand and to show how capital gain expectations can be a destabilising influence – i.e. the lagged effects of past price gains can drive the market price away from long-run market-worth. Investing based on the outputs of past price-based valuation models appear to be more of a game-of-chance than a sound investment strategy.

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Despite the global financial downturn, the Australian rail industry is in a period of expansion. Reports indicate that the industry is not attracting sufficient entry level and mid-career engineers and skilled technicians from within the Australian labour market and is facing widespread retirements from an ageing workforce. This paper reports on a completed qualitative study that explores the perceptions of engineering students, their lecturers, careers advisors and recruitment consultants regarding rail as a brand and of careers in the rail industry. Findings are presented about career knowledge, job characteristic preferences, branding and image and indicate that rail as a brand has a dated image, that young people and their influencers have little knowledge of rail careers and that rail could better focus its image and recruitment strategies. Conclusions include suggestions for more effective attraction and image strategies for the industry and for further research.

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Attracting and retaining a skilled labour force is a critical yet complex issue for rural and remote communities. This article reports the findings of a study investigating the current approaches to recruitment and retention in two separate Australian regions. Building on previously developed models, the research analyses the roles employers and the wider communities are playing, or potentially could play, in addressing issues that influence labour shortages. The findings of the research highlight the complexities of employee attraction and retention and emphasise the need for communities and businesses to work together to overcome labour shortages in rural and remote locations.

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Attracting and retaining a skilled labour force is a critical yet complex issue for rural and remote communities. This article reports the findings of a study investigating the current approaches to attraction and retention in two separate Australian regions. Building on previously developed models, this research analyses the roles employers and wider communities are playing, or potentially could play, in addressing issues that influence labour shortages. The findings of this research highlight the complexities of labour attraction and retention and emphasise the need for communities and businesses to work together to overcome labour shortages in rural and remote locations.

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An experimental set-up was used to visually observe the characteristics of bubbles as they moved up a column holding xanthan gum crystal suspensions. The bubble rise characteristics in xanthan gum solutions with crystal suspension are presented in this paper. The suspensions were made by using different concentrations of xanthan gum solutions with 0.23 mm mean diameter polystyrene crystal particles. The influence of the dimensionless quantities; namely the Reynolds number, Re, the Weber number, We, and the drag co-efficient, cd, are identified for the determination of the bubble rise velocity. The effect of these dimensionless groups together with the Eötvös number, Eo, the Froude number, Fr, and the bubble deformation parameter, D, on the bubble rise velocity and bubble trajectory are analysed. The experimental results show that the average bubble velocity increases with the increase in bubble volume for xanthan gum crystal suspensions. At high We, Eo and Re, bubbles are spherical-capped and their velocities are found to be very high. At low We and Eo, the surface tension force is significant compared to the inertia force. The viscous forces were shown to have no substantial effect on the bubble rise velocity for 45 < Re < 299. The results show that the drag co-efficient decreases with the increase in bubble velocity and Re. The trajectory analysis showed that small bubbles followed a zigzag motion while larger bubbles followed a spiral motion. The smaller bubbles experienced less horizontal motion in crystal suspended xanthan gum solutions while larger bubbles exhibited a greater degree of spiral motion than those seen in the previous studies on the bubble rise in xanthan gum solutions without crystal.

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Hollow micro-sized H2(H2O)Nb2O6 spheres constructed by nanocrystallites have been successfully synthesized via a bubble-template assisted hydrothermal process. In the reaction process, H2O2 acts as a bubble generator and plays a key role in the formation of the hollow structure. An in situ bubble-template mechanism has been proposed for the possible formation of the hollow structure. The spherelike assemblies of these H2(H2O)Nb2O6 nanoparticles have been transformed into their corresponding pseudohexagonal phase Nb2O5 through a moderate annealing dehydration process without destroying the hierarchical structure. Optical properties of the as-prepared hollow spheres were investigated. It is exciting that the absorption edge of the hollow Nb2O5 microspheres shifts about 18 nm to the violet compared with bulk powders in the UV/vis spectra, indicating its superior optical properties.

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Contamination of packaged foods due to micro-organisms entering through air leaks can cause serious public health issues and cost companies large amounts of money due to product recalls, consumer impact and subsequent loss of market share. The main source of contamination is leaks in packaging which allow air, moisture and microorganisms to enter the package. In the food processing and packaging industry worldwide, there is an increasing demand for cost effective state of the art inspection technologies that are capable of reliably detecting leaky seals and delivering products at six-sigma. The new technology will develop non-destructive testing technology using digital imaging and sensing combined with a differential vacuum technique to assess seal integrity of food packages on a high-speed production line. The cost of leaky packages in Australian food industries is estimated close to AUD $35 Million per year. Contamination of packaged foods due to micro-organisms entering through air leaks can cause serious public health issues and cost companies large sums of money due to product recalls, compensation claims and loss of market share. The main source of contamination is leaks in packaging which allow air, moisture and micro-organisms to enter the package. Flexible plastic packages are widely used, and are the least expensive form of retaining the quality of the product. These packets can be used to seal, and therefore maximise, the shelf life of both dry and moist products. The seals of food packages need to be airtight so that the food content is not contaminated due to contact with microorganisms that enter as a result of air leakage. Airtight seals also extend the shelf life of packaged foods, and manufacturers attempt to prevent food products with leaky seals being sold to consumers. There are many current NDT (non-destructive testing) methods of testing the seal of flexible packages best suited to random sampling, and for laboratory purposes. The three most commonly used methods are vacuum/pressure decay, bubble test, and helium leak detection. Although these methods can detect very fine leaks, they are limited by their high processing time and are not viable in a production line. Two nondestructive in-line packaging inspection machines are currently available and are discussed in the literature review. The detailed design and development of the High-Speed Sensing and Detection System (HSDS) is the fundamental requirement of this project and the future prototype and production unit. Successful laboratory testing was completed and a methodical design procedure was needed for a successful concept. The Mechanical tests confirmed the vacuum hypothesis and seal integrity with good consistent results. Electrically, the testing also provided solid results to enable the researcher to move the project forward with a certain amount of confidence. The laboratory design testing allowed the researcher to confirm theoretical assumptions before moving into the detailed design phase. Discussion on the development of the alternative concepts in both mechanical and electrical disciplines enables the researcher to make an informed decision. Each major mechanical and electrical component is detailed through the research and design process. The design procedure methodically works through the various major functions both from a mechanical and electrical perspective. It opens up alternative ideas for the major components that although are sometimes not practical in this application, show that the researcher has exhausted all engineering and functionality thoughts. Further concepts were then designed and developed for the entire HSDS unit based on previous practice and theory. In the future, it would be envisaged that both the Prototype and Production version of the HSDS would utilise standard industry available components, manufactured and distributed locally. Future research and testing of the prototype unit could result in a successful trial unit being incorporated in a working food processing production environment. Recommendations and future works are discussed, along with options in other food processing and packaging disciplines, and other areas in the non-food processing industry.

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This thesis concerns the mathematical model of moving fluid interfaces in a Hele-Shaw cell: an experimental device in which fluid flow is studied by sandwiching the fluid between two closely separated plates. Analytic and numerical methods are developed to gain new insights into interfacial stability and bubble evolution, and the influence of different boundary effects is examined. In particular, the properties of the velocity-dependent kinetic undercooling boundary condition are analysed, with regard to the selection of only discrete possible shapes of travelling fingers of fluid, the formation of corners on the interface, and the interaction of kinetic undercooling with the better known effect of surface tension. Explicit solutions to the problem of an expanding or contracting ring of fluid are also developed.

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This report provides the Queensland Department of Education and Training (DET) with independent evidence based data to enable the identification of barriers and enablers to effective attraction and retention of suitably qualified people to specialist teaching and non‐teaching roles in Queensland secondary schools. The scope of this report is to consider the strategic imperatives, trends, and drivers as they apply to the recruitment and retention of specialised teachers and non‐teaching professionals. The research was specifically designed to inform DET on innovative and novel strategies to recruit and retain staff within Education Queensland in areas specifically identified as at risk of experiencing shortages in the near future. Those areas considered to be at risk of experiencing shortages included: • Teaching principals • Specialist teachers in mathematics, science, industrial technology and design, and special education • Non‐teaching professional roles, such as speech pathologists, occupational therapists, physiotherapists and registered nurses providing services in schools to students with special needs.

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The electrodeposition of copper onto copper, gold, palladium and glassy carbon (GC) electrodes via a hydrogen bubble templating method is reported. It is found that the composition of the underlying electrode material significantly influences the morphology of the copper electrodeposit. Highly ordered porous structures are achieved with Cu and Au electrodes, however on Pd this order is disrupted and a rough randomly oriented surface is formed whereas on GC a bubble templating effect is not observed. Chronopotentiograms recorded during the electrodeposition process allows bubble formation and detachment from the surface to be monitored where distinctly different potential versus time profiles are observed at the different electrodes. The porous Cu surfaces are characterised with scanning electron microscopy, X-ray diffraction and cyclic voltammetric measurements recorded under alkaline conditions. The latter demonstrates that there are active sites present on electrodeposited copper whose coverage and reactivity depend on the underlying electrode material. The most active Cu surface is achieved at a Pd substrate for both the hydrogen evolution reaction and the catalytic reduction of ferricyanide ions with thiosulphate ions. This demonstrates that the highly ordered porous structure on the micron scale which typifies the morphology that can be achieved with the hydrogen bubbling template method is not required in producing the most effective material.

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Stone Baby: An Exploration of Affect and Trauma in Visual Art was held at the Block, QUT Creative Industries Precinct on August 27-28, 2014. At the conclusion of my Masters project, this exhibition was a showcase of the outcomes of my material and digital explorations in the form of installation, sculpture and film. My primary motivation can be described as a relational and ethical attempt to find a balance between the erotic and the aggressive. This is experienced in the self as feelings of attraction and repulsion in response to the new and unknown "other". Consequently creative practice is necessarily a complex affair that is experienced as a completely immersive and self-contained psychological space. It is within this space that both physical sensation and raw emotion are able to tangibly and conceptually interact with psychoanalytic theory, and concrete materials video and sound.

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As a functioning performing arts centre, commercial enterprise, tourist attraction and major national asset, Sydney Opera House must continue to demonstrate the optimal use and effectiveness of its facilities management (FM) to provide value for its stakeholders. To better achieve this, the Cooperative Research Centre for Construction Innovation focussed on the following three themes for investigation in the FM Exemplar Project — Sydney Opera House: digital modelling — developing a building information model capable of integrating information from disparate software systems and hard copy, and combining this with a spatial 3D computeraided design (CAD)/geographic information system (GIS) platform. This model offers a visual representation of the building and its component elements in 3D, and provides comprehensive information on each element. The model can work collaboratively through an open data exchange standard (common to all compliant software) in order to mine the data required to further FM objectives (such as maintenance) more efficiently and effectively. services procurement — developing a multi-criteria performance-based procurement framework aligned with organisational objectives for FM service delivery performance benchmarking — developing an FM benchmarking framework that enables facilities/ organisations to develop key performance indicators (KPIs) to identify better practice and improvement strategies. These three research stream outcomes were then aligned within the broader context of Sydney Opera House’s Total Asset Management (TAM) Plan and Strategic Asset Maintenance (SAM) Plan in arriving at a business framework aligned with, and in support of, organisational objectives. The Sydney Opera House is managed by the Sydney Opera House Trust on behalf of the Government of the State of New South Wales. Within the framework of the TAM Plan prepared in accordance with NSW Treasury Guidelines, the assimilation of these three themes provides an integrated FM solution capable of supporting Sydney Opera House’s business objectives and functional requirements. FM as a business enabler showcases innovative methods in improving FM performance, a better alignment of service and performance objectives and provides a better-practice model to support the business enterprise.

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In the global knowledge economy, knowledge-intensive industries and knowledge workers are extensively seen as the primary factors to improve the welfare and competitiveness of cities. To attract and retain such industries and workers, cities produce knowledge-based urban development strategies, where such strategising is also an important development mechanism for cities and their economies. This paper investigates Brisbane’s knowledge-based urban development strategies that support generation, attraction, and retention of investment and talent. The paper provides a clear understanding on the policy frameworks, and relevant applications of Brisbane’s knowledge-based urban development experience in becoming a prosperous knowledge city.

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In the global knowledge economy, knowledge-intensive industries and knowledge workers are extensively seen as the primary factors to improve the welfare and competitiveness of cities. To attract and retain such industries and workers, cities produce knowledge-based urban development strategies, and therefore such strategising has become an important development mechanism for cities and their economies. The paper discusses the critical connections between knowledge city foundations and integrated knowledge-based urban development mechanisms in both the local and regional level. In particular, the paper investigates Brisbane’s knowledge-based urban development strategies that support gentrification, attraction, and retention of investment and talent. Furthermore, the paper develops a knowledge-based urban development assessment framework to provide a clearer understanding of the local and regional policy frameworks, and relevant applications of Brisbane’s knowledge-based urban development experience, in becoming a prosperous knowledge city. The paper, with its knowledge-based urban development assessment framework, scrutinises Brisbane’s four development domains in detail: economy; society; institutional; built and natural environments. As part of the discussion of the case study findings, the paper describes the global orientation of Brisbane within the frame of regional and local level knowledge-based urban development strategies performing well. Although several good practices from Brisbane have already been internationally acknowledged, the research reveals that Brisbane is still in the early stages of its knowledge-based urban development implementation. Consequently, the development of a monitoring system for all knowledge-based urban development at all levels is highly crucial in accurately measuring the success and failure of specific knowledge-based urban development policies, and Brisbane’s progress towards a knowledge city transformation.

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: In the global knowledge economy, knowledge-intensive industries and knowledge workers are extensively seen as the primary factors to improve the welfare and competitiveness of cities. To attract and retain such industries and workers, cities produce knowledge-based urban development strategies, where such strategising is also an important development mechanism for cities and their economies. This paper investigates knowledge-based urban development strategies of Brisbane, Australia that support generation, attraction, and retention of investment and talent. The paper puts forward a clear understanding on the policy frameworks, and relevant applications of Brisbane’s knowledge-based urban development experience in becoming a prosperous knowledge city, and concludes by providing invaluable insights and directions for other cities seeking knowledge-based urban development.