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Core–shell SiCw@TiC composite whisker-reinforced Al2O3 ceramics: Preparation, properties, and toughening mechanisms
No full textIn this study, we propose a novel approach to increase the fracture toughness of Al2O3 ceramics by incorporating core–shell structural composite whiskers as secondary phases. In particular, Al2O3 composite ceramics reinforced with TiC-coated SiC whiskers (SiCw@TiC) were successfully fabricated through a combination of molten salt synthesis and spark plasma sintering (SPS). The SiCw@TiC whiskers feature a SiCw core and a TiC shell layer (~85 nm thick) composed of nano-sized TiC grains. Remarkably, the core–shell structure is preserved within the Al2O3 matrix after sintering, forming a unique composite toughening phase. The interfacial regions surrounding the whiskers exhibit a complex geometric configuration and multi-dimensional heterogeneities, including variations in phase composition (Al2O3/SiC/TiC), grain size (micron-/nano-scale), and thermal expansion coefficient (3.8×10−6–7.4×10−6/K), which collectively generate a sophisticated stress field. This intricate microstructure enables the SiCw@TiC whiskers to dissipate crack propagation energy through multiple mechanisms, significantly improving the fracture toughness of the Al2O3 matrix. The resulting Al2O3–SiCw@TiC composite ceramics demonstrate exceptional mechanical properties, with a relative density of 99.16%±0.48%, Vickers hardness of 21.38±0.93 GPa, flexural strength of 693±49 MPa, and fracture toughness of 7.15±0.47 MPa·m1/2. This work establishes a paradigm for structural ceramic toughening through engineered core–shell architectures
Isolation and Characterisation of Oil and Proteins in West Australian Sandalwood (Santalum Spicatum) Seed
Get PDFSantalum spicatum is a long-lived shrub and a slow-growing hemiparasitic plant that grows naturally in two-thirds of southern areas of Western Australia. Its leading product of value is its heartwood, which can only be harvested after an estimated 15-20 years. The co-product of the sandalwood plant is its seeds, which can be harvested from the age of three years. The results from this study will provide essential knowledge for cultivators to receive intermediate returns by utilising sandalwood seeds
Technology Optimising Pain Management for People Living with Dementia
No full textThis research developed strategies for implementing PainChek®, a digital pain assessment tool for dementia patients in community settings. Using implementation science and the Behaviour Change Wheel, the study identified barriers and facilitators to adoption by family carers and healthcare professionals. By exploring implementation strategies and delivery modes, the research created a comprehensive plan for PainChek Ltd. The work aims to enhance pain management for people with dementia, potentially reducing unnecessary suffering through innovative mobile health technology
The application of novel nano-capsules containing probucol-lithocholic acid to counteract oxidative stress
No full textThis thesis developed bile acid-based polymeric nanoparticles to enhance targeted delivery of probucol for oxidative stress-induced hearing and retinal damage. The formulation improved cellular uptake and sustained release while overcoming biological barriers. In vitro and in vivo studies confirmed the potent antioxidant activity, reduction of oxidative markers, and activation of protective cellular pathways. This innovative delivery platform offers a promising approach for addressing neurosensory complications, including sensorineural hearing loss and retinal degenerative diseases
The effect of observation discontinuities on LEO real-time orbital prediction accuracy and integrity
No full textReal-time, high-accuracy orbital products for low Earth orbit (LEO) satellites are essential for LEO-augmented real-time positioning, navigation and timing services. In particular, complete and continuous global navigation satellite system (GNSS) observations onboard tracked LEO satellites are necessary to guarantee precise orbit determination (POD) and generate short-term pre
dicted orbits that can be fit with real-time ephemeris parameters. However, in practice, GNSS observations of LEO satellites often suffer from discontinuities
due to tracking problems, data transmission problems, or downlinking strategies. Understanding the effect of these observation gaps on orbit accuracy is therefore essential for developing strategies to minimize accuracy degradation in real-time LEO satellite orbits. This study investigates trade-offs between two suites of strategies for addressing multi-hour observation data gaps followed by short segments of tail data during reduced-dynamic POD. The first strategy, EP, involves sacrificing the tail data and extending the prediction time. The second
set of strategies retain the tail data but vary the POD strategies: the tested options include maintaining stochastic accelerations as estimable parameters (RP), not estimating stochastic accelerations (CP), or combining the RP-based orbits from the non-gap periods with the CP-based orbits during the gap (BP). Using real
GNSS observations from the LEO satellite Sentinel-6A, we evaluated the accuracy and integrity of these strategies for 1-h orbital predictions with assumed gap lengths of 3, 5, 7, and 9 h and tail data lengths set to 15, 30, 45, and 60 min.
Results show that the BP strategy achieves the highest prediction accuracy, with mean orbital user range errors (OUREs) of approximately 5.7 and 13.4 cm for a
3-h data gap followed by 60-min and 15-min tails, respectively. In contrast, the EP strategy demonstrates the highest integrity. For a 15-min tail, the 99.9% con
fidence level of the OURE for the EP strategy reaches approximately 3.1 and 8.7 dm for gap lengths of 3 h and 9 h, respectively. Overall, BP is the preferred strategy for maximizing prediction accuracy, while the EP strategy is preferable for short gaps and tails. The CP strategy provides a balanced approach, maintaining reasonably strong performance for both prediction accuracy and integrity
Digital twins and e-commerce in low-income communities in Sub-Saharan Africa
Get PDFComprising five refereed publications, this thesis develops an experimental framework using digital twins to facilitate analysis of sustainable development through virtual representations for low-income communities in Sub-Saharan Africa. E-commerce virtual interventions were designed in cyberspace before being implemented as a real project in Ghana’s Tetegu urban community. Artificial intelligence, including agent-based modeling and machine learning, aids in studying social well-being and the cumulative effects of interventions across domains with different levels of complexity and scale
The role of work design in entrepreneurship: A review and meta-framework
No full textEntrepreneurship is a critical driver of economic development, yet limited attention has been given to the role of work design in shaping entrepreneurial intentions, behaviors, and outcomes. Yet, literature at the nexus of work design and entrepreneurship is fragmented − and thus the evidence on the specific nature of these relationships is unclear. This systematic review investigates: how does work design shape entrepreneurial intention and entry? and how does founder work design shape individual and venture outcomes? Our integrative review identified four mechanisms that likely underlie the influence of work design on entrepreneurship—motivation, flexibility, capacity, and strain—and present them in a meta-framework to guide future research on how founders’ and employees’ work design emerges in start-ups, and how work design influences multilevel outcomes over time
A network science approach to identifying conditions for consensus building in social networks
Get PDFThis thesis explores how consensus emerges in social networks and online discussions. It introduces a multi-layer model to measure deliberation in Reddit threads and an agent-based model to study social diffusion driven by a committed minority. Findings highlight how discussion structure and actor interactions shape deliberation quality, and how network topology and the placement of the committed minority influence the probability and speed of successful diffusion
Healthcare students’ knowledge of antibiotic ineffectiveness in treating viral infections: a systematic review and meta-analysis
No full textBackground
The overuse of antibiotics by healthcare professionals is often associated with a lack of knowledge regarding the rational use of these medications. We synthesized and analysed existing evidence on healthcare students' knowledge of antibiotic ineffectiveness in treating viral infections to provide pooled global and regional estimates.
Methods
The PubMed®, Embase® (via Ovid) and CINAHL (via EBSCO) databases were systematically searched for studies published between 01 January 2014 and 31 December 2024 that reported Healthcare students’ knowledge of antibiotic ineffectiveness in treating viral infections. Pooled estimates and 95% CI of correct knowledge were determined using random-effects meta-analysis.
Results
Of the 9165 articles identified, 86 studies met the inclusion criteria. Most healthcare students correctly understood that antibiotics are ineffective against viruses, with 70.2% (95% CI: 65.6–74.8) demonstrating this understanding. Only 58.0% (95% CI: 51.4–64.6) knew that antibiotics are ineffective against colds and flu. There were no significant regional variations in the understanding that antibiotics are ineffective against viruses. However, notable differences were evident at the country level. Thailand (30.3%, 95CI: 23.8–37.8), Turkey (35.8%, 95% CI: 32.9–38.8), Mali (39.9%, 95% CI: 35.5–44.5), and China (45.7%, 95% CI: 43.5–47.9) demonstrated lower levels of knowledge, whereas Poland (94.0%, 95% CI: 90.4–97.5), the United States (98.0%, 95% CI: 94.5–99.3), and the United Kingdom (98.4%, 95% CI: 97.2–99.6) exhibited higher levels of understanding.
Conclusions
Our findings indicate significant knowledge gaps in the understanding of the ineffectiveness of antibiotics against viruses in many countries. These knowledge gaps have important implications for the rational use of antibiotics and the prevention of resistance
The Influence of Exogenously Induced Stress and Performance-Based Feedback on Confidence
Get PDFThis thesis investigates how exogenous stress and performance-based feedback affect individual confidence, measured through prediction intervals. Two experiments reveal that stress slightly increases confidence, while feedback has no significant effect—alone or combined with stress. An exploratory analysis considers the influence of Big Five personality traits and risk attitudes on confidence. The findings suggest that while stress has a statistically significant effect, its economic significance is minimal, and feedback does not meaningfully influence confidence