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Examining the psychosocial affordances of online learning: Perceptions of gifted adolescents and their teachers
No full textThis thesis investigated the psychosocial affordances of online learning as perceived by gifted adolescents, teachers, and counsellors across six gifted high schools in Saudi Arabia. Research on educational technology for gifted students is limited, especially in fostering psychosocial development through online learning. Gifted adolescents, diverse in social competence and psychosocial needs, often struggle with poor self-concept and social adjustment during adolescence. Drawing on Erikson’s (1963) Theory of Psychosocial Development and Gibson’s (1966, 1977, 1979) Affordance Theory as a framework, this study attempted to fill this gap by examining how online learning environments address the psychosocial needs of gifted students and evaluated their impact on psychosocial development. The study employed dataset triangulation, using quantitative analysis of strength-based survey results and qualitative assessment of participant attitudes, opinions, and behaviours, organising survey and interview data into thematic clusters.Data collected from 300 gifted students, ten gifted teachers, and six school counsellors revealed that online learning enhanced creativity and academic quality for gifted students. Technology was viewed as essential for self-directed learning and career readiness. However, opinions varied regarding its efficacy in addressing psychological needs and building community. Teachers prioritised learner-centred approaches and recognised their evolving role as facilitators in online environments yet exhibited varying levels of digital expertise. Educators expressed a favourable attitude towards digital tools for academic purposes, highlighting their potential to optimise the learning experience and address students’ psychological well-being. Qualitative data highlighted educators’ multifaceted role in fostering effective communication, creating positive learning environments, and supporting academic skill development. Overall, this study informs stakeholders about the value of psychosocial affordances in online learning environments.</p
Tunable Properties of YBa2Cu307-x Superconducting Thin Films enabled by Varying the Energy Distribution of the Plume with Target to Substrate Distance
No full textSince the discovery of superconductivity, high-temperature superconductors (HTS) such as Yttrium Barium Copper Oxide (YBCO) have remained at the forefront of research due to their exceptional critical current density ( ) and high critical temperatures. These properties make YBCO appealing for applications in Superconducting Quantum Interference Device (SQUIDS), electricity transmission lines and Magnetic Resonance Imaging magnets. Pulsed Laser Deposition (PLD) has emerged as a versatile technique for fabricating high-quality YBCO thin films, enabling enhanced flux pinning, increased critical current density, and optimized surface morphology through precise control of deposition conditions and defect engineering - both of which are pivotal areas of research. Recent research has focused on optimizing the fabrication of ultra-thin films (A critical deposition parameter, the Target-to-Substrate Distance (TSD), plays a key role in determining film properties and surface morphology by influencing multiple deposition parameters, including energy distribution of the plume, flux rate, and surface diffusion rates. This work systematically investigates the structural and electromagnetic properties of YBCO thin films as a function of TSD, focusing on electromagnetic properties, film thickness, critical temperature, crystallinity, stoichiometry, surface morphology and growth modes. Reference to plume propagation models and growth processes were also used to aid this analysis. Characterization techniques including Magnetization measurements, X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM), were employed to provide a comprehensive evaluation. Notably, high crystallinity and critical current density were preserved over a large 50mm TSD range under a high laser fluence. Unexpectedly, this trend remained substantial despite a decrease in total film thickness with increasing TSD. Remarkably, while the performance remained largely unchanged, surface properties and other structural features are shown to be easily tunable as a function of TSD, which would be desirable for a broad range of potential applications in electronics and energy handling.Further structural analysis, including lattice parameters, oxygen content and formation mechanisms, was conducted via XRD to understand the preservation of these properties. This study presents the first report of a triple layered strain structure emerging from a monolayered deposition in YBCO thin films fabricated via PLD on single crystal substrates. This phenomenon, observed over this large 50mm TSD range, was identified by the presence of a triple peak in −2 scans, despite significant variations in growth mode and thickness between layers. This multilayer strain formation is attributed to significant deviations from typical deposition conditions, particularly high laser fluence which amplifies strain throughout the film. A precise balance between the competing effects of TSD and laser fluence is required to facilitate this formation, as these parameters influence not only structural and electromagnetic properties but also the transition between monolayer and multilayered strain formation.These findings demonstrate significant potential for advancing ultra-thin YBCO superconducting films, particularly in single-photon detectors and electronic applications. The results obtained in this work also suggest that a similar simplicity, which is overlooked due to space and design constraints in PLD chambers, can be adopted in other areas of science and technology, and potential applications where PLD process is the key fabrication technique.</p
Design of Passive Gravity Compensators for Linear Motion Based on Permanent Magnets
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A socio-technical approach to the design and implementation of digital health solutions
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A digital twin simulation platform for 4D millimeter-wave radar-based navigation in underground mining environment
No full textIn underground mining, safe navigation and quick decision-making are critical and essential, especially in emergencies. Environmental conditions, such as, visibility, high humidity, and high amount of dust suspension, make traditional camera or LIDAR-based navigation risky and unreliable. Radars, particularly 4D millimetre-wave (MMW) radar, are relatively robust against these environmental factors, which make them suited to underground mine environment navigation applications. However, iterative testing and refinement of radar systems in real mines remain costly, time-consuming, and potentially hazardous.To address these challenges, a digital twin simulation platform for developing and evaluating a 4D MMW radar-based navigation system for underground vehicles is presented. In the platform, a complex underground mining environment is reconstructed using Gazebo and ROS2, including two specific structures: flat-roof and arched-roof mine tunnels inspired by Queensland Mine Rescue Service (QMRS) conditions. Various obstacles, including rocks, overhead signs, lights, ladders, and a worker model, are integrated into the arched-roof tunnel to evaluate the radar’s detection capabilities. A simplified driftrunner-based vehicle model was designed with radars mounted at two heights: 1.25 m and 0.3 m. Radar parameters were set according to ARS548 hardware specifications using Gazebo’s plugin, while post-processing introduced Gaussian noise and random point cloud reduction to simulate real-world data sparsity and uncertainty.Simulation tests were conducted to analyse radar performance at three distances (5 m, 10 m, and 15 m) along the tunnel centre and two radar heights. Results indicate that radar mounting height significantly influences detection capabilities. At a height of 1.25 m, elevated features, such as, overhead signs and lights can be captured effectively, but ground-level obstacles remained undetected at close range. In contrast, at a lower radar height of 0.3 m, ground-level obstacles can be detected with greater clarity, but elevated features were less distinguishable. This highlight is a tradeoff between the vertical coverage and the ground-level detection, showing the requirement for optimized radar positioning for improved navigation performance.The developed platform allows safe, iterative testing of radar-based systems under simulated underground conditions, providing key insights into sensor configuration, obstacle detection, and point cloud processing. Although currently focused on simulation, the platform supports future integration with physical radar systems to further refine radar plugins and algorithms. This work ultimately aims to enhance safety and decision-making in underground operations.</p
Chloride penetration of shotcrete with crushed waste glass aggregates
No full textShotcrete is a type of concrete sprayed onto surfaces using a nozzle, making it ideal for applications with irregularly shaped substrates such as rock support in deep mines and retaining walls. Unlike conventional concrete, however, shotcrete requires a mix design with enhanced pumpability which is typically achieved by increasing sand content. On the other hand, the surge in construction projects has led to sand depletion due to excessive natural sand extraction, resulting in environmental damage, habitat loss, and beach erosion. To mitigate the sand depletion issues, alternative synthetic aggregates made from crushed waste glass (CWG) have been explored in recent years as substitutes for natural sand in shotcrete production. Evaluating CWG's feasibility in shotcrete involves assessing its performance to ensure it meets standard requirements, particularly its longterm durability. One critical durability factor is shotcrete’s resistance to chloride penetration. Chloride ions, commonly originating from seawater or contaminated groundwater, can infiltrate shotcrete, corrode embedded rebar, and compromise structural integrity, ultimately reducing its lifespan. This study tested shotcrete mixes with varying percentages of CWG for chloride penetration resistance using the Rapid Chloride Penetration Test (RCPT) and the bulk resistivity method. Results demonstrated that incorporating CWG in shotcrete significantly improved durability, showcasing its potential as a sustainable alternative in shotcrete production.</p
Visualisation Techniques for Unveiling the Influence of Distributed and Renewable Generation Units in Distribution Networks
No full textThe abstract for this item has not been populated.</p
Shear testing of rock bolts for hard rock mining
No full textThe shear capacity of hollow rock bolts is questionable due to the lack of experimental data. To address this limitation, the shear strength of three different types of hollow bolts, including “X”, “S” and “E” grade rock bolts were studied using the double shear test method under hard rock conditions. The outcomes revealed that the shear force depends on the bolt type. The “X” grade hollow bolt can tolerate larger vertical movement and shear force. In addition, it was found that the shear load capacity of hollow bolts is not necessarily around 70% of UTS. The results showed that the “X” and “S” grade bolts are more brittle due to their higher UTS and lower elongation capacity.</p
Trust: Four Studies on Innovation, Risk, and Market Dynamics in Decentralized Finance
No full textThis thesis is comprised of four studies on the role of trust in financial transactions, from 5,000 B.C. to contemporary cryptocurrency markets.The first study (Chapter 3) evaluates the literature on the evolution of financial trust, tying it to modern advances in financial technology and decentralized finance. Most crucially, this chapter recounts the pre-modern use of ‘virtual’ currency, including via promises and orally traded stones. It also examines early proto-stablecoins, reinforcing how many of today’s financial needs–and early versions of contemporary solutions–existed in the past. It also demonstrates the extreme importance trust plays in financial transactions, and the many, many ways that trust is sought and demonstrated. From Roman Empire trade receipts created in ancient triplicate, to paper money in 7th Century China, as well as innovations which have long since vanished, financial innovation has long been an important part of every economy of note–and every successful innovation must be trusted to survive.The following three studies examine contemporary cryptocurrency markets to further our understanding of trust at the frontier of contemporary finance.The first of these cryptocurrency studies (Chapter 4) analyzes perpetual futures, a novel derivatives contract first proposed by Nobel Laureate Robert Shiller, but only fully implemented in cryptocurrency markets. In addition to looking at spillover effects between perpetual and traditional financial markets, this chapter examines the unique trust structure of perpetual futures–which on Binance includes socialized losses and a reserve fund denominated in cryptocurrencies–as well as 'funding rates', periodic payments between traders. It also tests arbitrage opportunities in Bitcoin quarterly futures, contributing to our understanding of market efficiency in cryptocurrency markets over time.The next study (Chapter 5) examines the collapse of the TERRA/LUNA algorithmic stablecoin pair, analyzing contagion effects spread across markets, contributing to our understanding of how distrust spreads across cryptocurrency markets, while also testing trust in stablecoin issuers via market prices of issued assets. This chapter finds that traders have clear preferences for clearly defined, transparently-backed assets in a crisis. This is demonstrated by the market price of Tether, which traded at a 5% discount, while other stablecoins with more transparent and regulated reserve structures traded at a premium. Given Tether is supposed to trade for essentially $1 at all times, any non-minor deviation from the market price offers arbitrage profits to speculators, assuming they have faith in the underlying asset. That Tether traded at a discount for so long, while rivals traded at a premium, opens a window into trader behavior and the value of trusted and transparent reserve structures in a crisis.The final study (Chapter 6) investigates the collapse of FTX, analyzing how contagion effects spread across markets during an exchange collapse. This study examines the price action of major cryptocurrencies stranded on the FTX exchange during a unique period where trading was allowed but withdrawals were almost entirely halted. This period provides insight into trader behavior and asset preference in advance of exchange bankruptcy. Major divergences between prices on FTX and the wider cryptocurrency markets were found, demonstrating how the unique pressure of an exchange collapse and withdrawal halt can dramatically influence market prices. The study examines an on-chain FTX-controlled Ethereum wallet, providing further detail about the FTX collapse while partially confirming FTX statements around the withdrawal halt. Verifying these statements, to the extent possible, was important as FTX was accused of fraud.As a whole, this dissertation enhances our understanding of financial trust in contemporary digital markets, with empirical evidence demonstrating how contemporary financial challenges–from counterparty risk, identity verification, asset backing structures, market contagion, liquidity crises, and reputational risks–are enduring aspects of finance across eras. This research provides frameworks for evaluating market trust in novel financial asset classes while placing the contemporary decentralized financial space within the broader evolution of financial markets, highlighting the ways financial innovation can both create and destroy trust in value exchange.</p
Gardens, agency and citizenship of people with dementia: An opportunity to dig deeper?
No full textThe abstract for this item has not been populated.</p