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Diffuser-Based Lensless Light-Field Imaging
No full textLight-field cameras have become a groundbreaking technology for capturing high dimensional light information, enabling enhanced visual perception across a wide range of applications. These systems record both spatial and angular information of light, allowing for innovative functionalities such as depth estimation, refocusing, and multi perspective visualisation. Such capabilities have made light-field cameras invaluable in fields like computer vision, computer graphics, microscopy, virtual reality (VR), three dimensional (3D) reconstruction, and medical imaging. However, light-field imaging systems are not without challenges. A widely adopted design involves the use of microlens arrays to collect light-field data. Although effective, this approach introduces an inherent trade-off between spatial and angular resolutions. Furthermore, incorporating microlens arrays into the imaging system adds complexity to the optical and mechanical design, increasing production costs and calibration requirements.As researchers seek to overcome these limitations, such as the spatial–angular resolution trade-off, increased system complexity, and growing costs of production and calibration, lensless imaging systems have emerged as a promising alternative to traditional lens-based designs, offering a simpler and more compact approach. Lensless imaging systems have gained significant attention in recent years because they eliminate the need for lenses, providing advantages such as simplified designs, reduced size, and lower fabrication complexity. Among the various advances in lensless imaging, lensless light-field imaging has shown potential to capture high-dimensional light information without the need for complex optical components. However, despite these advantages, lensless lightfield imaging faces a significant challenge: errors in light-field reconstruction. These errors arise because of the system’s reliance on computational methods to reconstruct light-field data. Such reconstruction errors can degrade the quality and usability of the reconstructed data, limiting the practical applications of lensless light-field systems. This thesis aims to provide lensless light-field imaging solutions that benefit from spatial invariance and pseudo-randomly arranged relief structures of the diffuser. The motivation behind this thesis is to provide a desirable high-quality light-field reconstruction while offering an attractive low computational complexity.</p
A Qualitative Exploration of Food Insecurity and Institutional Support Among International Students at a Regional Australian University
No full textIntroduction: Food insecurity among international students studying in Australian universities is a growing concern, but limited research has explored their experiences in regional contexts. This study explores food insecurity experiences among international students studying at a regional Australian university, focusing on challenges with food access and the effectiveness of available support services. Methods: Student-led focus groups were employed to explore food insecurity experiences among a sample of international students. A semi-structured guide probed students about food access issues and perceptions of available support services, and student recommendations for improvement were explored. Audio recordings were transcribed, and data were thematically analysed using Braun and Clarke's six-phase framework. Results: International students (n = 17) participated in four focus groups. Thematic analysis identified challenges affecting students' food security, including inadequate campus food options, the high cost of living, and a lack of culturally appropriate food choices in Australia. Students employed various coping strategies, such as using dietary supplements, meal prepping, and seeking discounted and/or frozen foods. International students encountered significant barriers to accessing support services, including inefficient pantry operations, perceived stigma, and poor communications about options. Based on these findings, participants suggested improvements in pantry management and expanded financial support for university students. Conclusions: This study highlights the significant challenges and coping strategies related to food insecurity among international students at a regional Australian university. So What?: Our findings emphasise the urgent need for tailored, culturally appropriate interventions and improved communication strategies that support international students' agency in accessing healthy, appropriate food.</p
Acoustic Differences in the Production of Plain and Emphatic Consonants in Speakers of Ruwaili Arabic
No full textNumerous studies have investigated Arabic dialects, including Syrian, Jordanian, Egyptian, and Iraqi Arabic. While some research has focused on dialects within Saudi Arabia, such as Najdi and Hijazi Arabic, certain regional varieties remain understudied. Among these is Ruwaili Arabic, which has received little scholarly attention. One of the primary objectives of this thesis is to provide a comprehensive phonetic and phonological analysis of this dialect.A central issue in Arabic phonetics and phonology is emphasis spread, a phenomenon that has been debated among scholars. Therefore, another major objective of this thesis is to investigate emphasis spread in Ruwaili Arabic, with a particular focus on reliable acoustic cues, the extent and directionality of emphasis spread, and the role of gender in its realization. To address these questions, the thesis comprises four Chapters (Chapters 3-6), each focusing on a specific aspect of emphasis.</p
Landscape evolution and climate change on the Antarctic Peninsula
No full textInteractions between geological and glaciological processes operating at very different timescales have shaped the Antarctic Peninsula. Basement rocks formed during the Phanerozoic in a complex subduction zone. Since the inception of the ice sheet ~34 Ma, multi-thousand-year scale climate change has driven the growth and fluctuation of the ice sheet and controlled surface processes like erosion. In the last few decades, atmospheric and oceanic warming has forced rapid readjustments of ice shelf and glacier configurations. However, the geological and glaciological history of the Antarctic Peninsula remains fragmented. This is mainly due to a lack of field-based observations and the temporal limits of high-quality satellite data. For many remote nunataks, the published geological record is sparse and geochronological constraints can be non-existent. Records of past ice behaviour are spatially limited to accessible areas of the coast which leads to great uncertainty for the ice sheet interior. Recent changes to ice shelves and outlet glaciers can be observed using modern satellite data, however, robust baseline measurements pre-2000 are rare.The overarching aim of this thesis is to better constrain the timing and magnitude of geological and glaciological processes driving landscape evolution on the Antarctic Peninsula from million-year to decadal timescales. What is the geological history of understudied basement rocks? How has ice sheet thickness evolved over long timescales? How have ice sheet outlet glaciers changed in the era of anthropogenic climate disruption? Three sets of Objectives address the research questions posed above: (1) Describe the geology and determine the age, origin, and deformation history of understudied nunataks on the central Antarctic Peninsula, (2) Analyse the exposure, burial, and erosion history of nunataks in the ice sheet interior to provide new constraints for the ice thickness history, and (3) Measure decadal-scale changes to outlet glaciers that have been affected by recent ice shelf collapse and calculate net magnitude of ice loss. Mount Faith, Mount Sullivan and Engel Peaks in northeast Palmer Land serve as case studies for Objectives (1) and (2). Former Larsen B Ice Shelf tributary glaciers on the northern Peninsula were studied for Objective (3).Whole rock geochemistry as well as zircon petrochronology (e.g., U-Pb isotopes, Ti, P, Ce, Eu, and other rare earth elements) from 34 granitoid samples were used to investigate the timing and nature of plutonism in northern Palmer Land. Novel crystallisation ages are Early Jurassic (188 – 179 Ma) for calc-alkaline, peraluminous granitoids at all three locations. Two samples exhibit Early Cretaceous (116 – 120 Ma) recrystallisation related to a large-scale deformation event. These are the most thorough geochronological constraints obtained thus far from northern Palmer Land and will significantly improve detail in reconstructions of Mesozoic Gondwanan tectonics. Cosmogenic nuclides (10Be, 26Al) were measured in the same samples and provide new constraints on palaeo-ice thickness and bedrock erosion rates. Ratios of 26Al/10Be indicate that samples >170 m above the current ice surface have never been buried and are eroding as slowly as 0.09 ± 0.02 m Ma-1. This indicates that ice sheet models overestimate past thickness on the Peninsula by hundreds of metres. New limits will better constrain deglaciation models which are crucial for projecting future sea-level rise. Structure-from-motion photogrammetry of 871 images from 1968 reveal former configurations of Larsen B Ice Shelf tributary glaciers decades before its collapse in 2002. Net ice loss for five glaciers between 1968 – 2021 was 35.3 ± 1.2 Gt related to ice shelf removal. Multi-decadal scale glacier observations reveal rapid and variable responses to ice dynamic changes and reveal a disproportionate contribution to global sea-level rise from the region. Overall, this thesis adds to the understanding of landscape evolution and interactions with climate on the Antarctic Peninsula at multiple timescales.</p
Milk, Magic and the Disappearing Cow: Advertising Cow’s Milk in Australia during the Interwar Period
No full textThe movement during Australia’s interwar period to make milk a drink for everyone was a multimedia affair that cut across institutions of public health, entertainment and parenthood, reaching deep into public and private spaces. Using New South Wales as a case study, we examine how state government and dairy farmers constructed powerful new narratives of milk’s magic that excluded the cow who supplied that milk. Well before cows were physically distanced from most city and country residents, advertising removed them from the visual culture of milk, replacing the cow with the fetishized milk bottle and re-gendering milk to support new connotations of masculinity and national health. The many and varied interests that coalesced in this effort help to explain how cow’s milk became so deeply entrenched in Australian culture and the challenges faced by animal activists working to uproot these practices and end the cruelty of the dairy industry.</p
New and Old China: Debating Chinese-Australian Nationalism, 1894 – 1938
No full textThis thesis explores the ideological complexities of Chinese-Australian thought during the early 20th century, during which time the overseas Chinese experienced massive changes due to the impact of China’s politics. The transformations in overseas Chinese communities were both political and cultural, witnessing intellectual collisions between the radicals and conservatives. This thesis traces the debate on the leadership of the Qing Court, Yuan Shikai, Sun Yat-sen, and Chiang Kai-shek in the Chinese-Australian community from 1894 to 1938. It considers how Chinese-Australian political intellectuals and the Chinese community were influenced by China’s politics and ideological collisions. The main source materials for this study are drawn from Chinese-language newspapers published in Australia during this period. These newspapers and the Chinese merchants and political groups behind them constructed a discourse around the new-versus-old struggle. This discourse shows how the Australian Chinese-language press played a crucial role in helping its readers understand their relationship with China and the world, through a discussion of different ideologies from the late 19th century to the outbreak of the Sino-Japanese War of 1937.</p
Investigating calcium signalling, lipid homeostasis and GPX4 in Alzheimer's disease using iPSC-derived neurons
No full textThe abstract for this item has not been populated.</p
Ocean Literacy for Ocean Sustainability: Reflections From Australia
No full textEnsuring a sustainable future for the global ocean requires meaningful dialogue and engagement with society. Around the world, efforts to engage and collaborate with society increasingly emphasise ocean literacy as a potential tool for engaging and educating people on ocean issues. A conceptual measure of people’s awareness, attitudes, and behaviours towards the ocean, ocean literacy has been highlighted as a key objective in recent ocean sustainability agreements and initiatives, including the UN Decade of Ocean Science for Sustainable Development. In Australia, research and applied interest in ocean literacy is burgeoning. It is therefore timely to take stock and explore recent work that may inform future pathways towards supporting and engaging society in achieving ocean sustainability. Here, we explore examples of ocean literacy research and practice in Australia, to develop prospective thinking on inter/transdisciplinary approaches for advancing ocean literacy under sustainability objectives. In doing so, we anticipate the next steps for progressing ocean literacy in the Australian context, including supporting ocean learning and education, engaging communities at all levels, fostering cross‐sector collaboration on connecting people to the ocean, and building strong and actionable policy and funding frameworks to ensure long‐term impact. We emphasise the need to collaboratively develop a national ocean literacy strategy to guide and structure these efforts and to establish an Australian ocean literacy coalition to facilitate research, cross‐sector collaboration, and implementation in practice.</p
2D/3D numerical modelling of an underground longwall installation road
No full textThis paper presents a comprehensive numerical case study on the ground response and support performance for an underground coal mine longwall installation road. Coal mining installation roads represent high-risk excavations due to their large spans, which can lead to significant roof displacement. Three numerical modelling methodologies—FLAC2D, FLAC3D, and 3DEC—were employed to assess the ground behaviour and the effectiveness of ground support in mitigating such risks. These methods evaluated roof displacements, roadway convergence, and excavation damage zone characteristics. Models utilised the Generalized Hoek-Brown constitutive model in FLAC2D/3D to simulate the heterogeneous lithological units and anisotropic stress fields. Longitudinal Displacement Profiles (LDP) of the excavation were developed in FLAC3D, and Ground Reaction Curves (GRC) were extracted for both FLAC2D and 3DEC (quasi-3D only in this work) to determine the unsupported relaxation factor. A bonded block model (BBM) was incorporated in 3DEC to capture block-scale deformation. Model calibration and sensitivity analyses, including block size effects, were conducted to ensure reliable simulations. Results from the numerical analyses indicate that the designed support system is sufficient to control deformation, with the final roof-floor and rib-rib convergence remaining within acceptable limits (<2.5%). However, discrepancies between 3DEC and FLAC2D/3D were observed in roof displacements near the excavation surface, highlighting the influence of modelling methodology.</p
Squat Crack Propagation in Rails Induced by Rolling Contact Fatigue
No full textRolling contact fatigue (RCF) cracks in rails are critical concern for railway infrastructure, impacting safety, maintenance costs, and service life. RCF cracks initiate and propagate due to high stresses generated by cyclic wheel-rail contact. These cracks can form on the rail surface or within the subsurface of the rail head, exhibiting intricate patterns and enlarging under subsequent loads. The understanding and estimation of crack growth are paramount.Squat cracks are widely recognized as a common type of RCF crack, which impact railway safety management due to their popularity and the significant increase in recent years. Large squats, which can cause depressions and spalling, lead to an elevated vertical dynamic load on wheelsets, accelerating deterioration of both the track and certain vehicle components. This deterioration is often accompanied by excessive noise and vibration, resulting in increased complaints against rail operators. Additionally, squats can compromise the effectiveness of ultrasonic rail testing by masking subsurface defects. The primary risk associated with squat defects is the potential for these cracks to propagate downward into parent rail along a transverse plane, which could ultimately result in a catastrophic rail fracture if left unaddressed.Numerical studies, particularly those utilizing finite element models, have focused on stress intensity factors (SIFs) at the crack front to understand crack stability, growth trajectory, and propagation rate. Early 2D FEM studies indicated that smaller cracks tend to grow parallel to the rail surface, with observations consistent across several investigations showing that RCF cracks propagate at an acute angle before turning downward. However, these 2D models are limited as they can only address crack opening (Mode I) and shearing (Mode II) and often overestimate crack growth rates by neglecting three-dimensional constraints. Consequently, 3D FEM models have been developed to better capture the complex fracture mechanisms and Stress distribution. Despite these advancements, a systematic investigation of the sensitivity of wheel passage over pre-existing cracks and growth of twisted squat crack remains lacking, which is crucial for accurately predicting the associated damage under varying operational conditions.To overcome the current limitations in numerical modelling of squat crack propagation, a two-stage simulation strategy was proposed to investigate the mechanisms of RCF-induced squat-type cracks in rails. It consisted of a dynamic FEM for wheel and rail interaction and a coupled static FEM/BEM for crack growth. The study found that there are two critical wheel positions for crack propagation during wheel approach and departure from the pre-existing crack. The different cracking mechanisms at these two critical wheel positions are correlated with the local physical phenomena. These include the traction at the wheel/rail interface, the relative distance between the contact patch and the crack, and the sliding at crack faces. Additionally, the twisting of the cracks from the transverse plane to the longitudinal plane at the railhead significantly reduces crack growth in mode I but enhances crack propagation in modes II and III.The study also explored the effects of lateral wheel position variation, twist angles, crack face friction, and crack size on squat cracks. The results reveal that squats are significantly influenced by contact load variation, as increasing the distance between the crack center and contact center reduces stress intensity around the crack. Mode II emerges as the dominant growth mode, even when cracks extend beyond the contact region. Additionally, twist angles promote a shift in mode II and mode III depending on the angle. Importantly, when crack face friction is introduced, mode II remains the dominant growth mode, with a discernible reduction in both mode II and III.The current work investigated actual squat crack growth from an early-stage tiny squat with a leading branch to the mature squat with both leading and trailing branches. The research highlights the three-dimensional propagation of squat cracks, occurring not only on the rail surface but also extending beneath it. The results show the formation of trail crack is due to the combined cracking modes of shearing and tearing and large opposite mode II shearing at the field corner of the crack. Maximum Shear Stress (MSS) criteria are valid before the squat crack grows to a certain deep. Mode I could assist in crack turning down at the mature growth stage.The findings are expected to contribute for advanced maintenance technologies and improved rail material designs, ultimately contributing to safer and more efficient railway operations.</p