Sydney eScholarship
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Piezoresistivity of 3D-printed Thermoplastic Polyurethane/Carbon Black Nanocomposites
No full textPiezoresistive polymer nanocomposite materials represent a class of smart materials capable
of converting mechanical deformation into measurable electrical signals. These materials, often
composed of conductive fillers combined with a flexible matrix/substrate, are of significant
interest for various applications such as structural health monitoring and wearable devices. The
unique combination of mechanical flexibility and high piezoresistive sensitivity makes them
superior to traditional sensing materials. Recently, different techniques have been developed
to process these polymer nanocomposites for creating strain sensors. Among these, 3D printing
has garnered considerable attention for its customizability and precision. However, a
comprehensive understanding of the process-structure-property relationship is still lacking,
hindering further optimisation of sensor performance. The effects of printing parameters, such
as infill angle and layer orientation, on the piezoresistive response remain underexplored. This
thesis systematically investigates the electromechanical behaviour of 3D-printed piezoresistive
sensors, focusing on the investigation of the effects of infill angle and layer orientation on
sensing performance. The study showed that as the infill angle increased, the mechanical
properties of the sample decreased while the piezoresistive sensitivity (gauge factor, defined
as ∆/0) increased. The sensitivity of the sample printed at an infill angle of 90° reached up
to 17, with a fast response speed of 44 ms, and only 5% drift in the signal output under 1000
cycles of loading. Moreover, it was found that samples with a biaxial layout showed increased
mechanical properties but with lower sensitivity. The work identifies the interplay between
printing conditions and sensor functionality, providing insights into tailoring piezoresistive
properties. This work also shows that the sensor can be used to detect the health of concrete
Local and indigenous knowledge in disaster risk reduction: Analysing multi-hazard housing reconstruction strategies in the Philippines
No full textThe place-based (“local”) and cultural (“indigenous”) knowledge of communities developed out of their embeddedness in their environments has provided them with time-tested approaches for disaster risk reduction (DRR). However, current DRR interventions often disregard local and indigenous knowledge (LIK) that could contextualise better responses to disaster impacts among affected populations. This thesis examined LIK in housing reconstruction in multi-hazard settings. First, it reviewed the state of knowledge of LIK in DRR scholarship through a systematic literature search, identifying the trajectories of its application to manage disaster impacts. Second, based on a case study in Itbayat, Batanes, Philippines, structural housing performance was quantified among the post-disaster dwellings built by Indigenous households in response to multi-hazard events. First-generation fragility functions were derived for Batanes Province contributing to more localised housing risk assessments in the country. Third, the socio-technical factors influencing multi-hazard housing reconstruction were elicited through interviews and focus group discussions. Factors such as the urgency of reconstruction, risk perceptions, financial capacities, and regulatory barriers on resource extraction affect how households build their dwellings, offering contextual shelter recovery insights. Finally, this thesis culminates with a proposed approach (as applied to the case study) to analyse collective safer construction practices of a residential building portfolio in multi-hazard settings while considering the socio-technical circumstances of the Indigenous community. This approach facilitates multi-hazard housing reconstruction decision-making useful for policymakers to enact safer construction interventions. Overall, this thesis highlights blending local capacities and resources with technical approaches to understand and improve the multi-hazard housing trajectories among Indigenous communities
Migrating Modernism. The Achitecture of Harry Seidler
No full textMigrating Modernism: The architecture of Harry Seidler is an interdisciplinary curatorial research project that brings together scholars in the fields of architectural history and late modernist art, to explore the work of Seidler & Associates.
The project examines how Seidler’s transnational education and émigré identity would shape an architectural philosophy and cross-disciplinary collaborations during Australia’s post-war economic boom in the second half of the 20th century.
Its focus will research Seidler’s collaborations with major international architectural figures such as Pier Luigi Nervi and Marcel Breuer, alongside commissions with major American artists including Josef Albers, Alexander Calder, Helen Frankenthler, Frank Stella and Sol LeWitt
Beyond Trade-Offs: Advancing Spatial-Temporal Forecasting In Transportation With Deep Learning
No full textAccurate and efficient traffic flow prediction is essential for modern IntelligentTransportation Systems (ITSs). As urban road networks and sensor infrastructuresexpand, forecasting methods must capture complex spatial–temporal dependencies whileremaining computationally tractable for real-time use. Traditional statistical methodsstruggle with non-linear patterns and large-scale data, whereas deep learning approaches—such as CNNs, RNNs, and GNNs—face challenges in modelling long-rangedependencies or incur high computational costs.
This thesis advances spatial–temporal deep learning for traffic flow and passengerdemand prediction, addressing the trade-off between accuracy and efficiency. First,CCDSReFormer introduces a criss-cross dual-stream Transformer with enhanced rectifiedself-attention and geographic–semantic masking, delivering improved accuracy with lower complexity. Second, ST-MambaSync fuses selective state-space (Mamba) andTransformer mechanisms, providing theoretical and empirical evidence of theircomplementarity, achieving notable reductions in prediction error, FLOPs, and inferencetime. Third, STDAtt-Mamba employs dynamic attention and state-space modelling tocapture heterogeneous passenger behaviours in multimodal public transit, outperformingexisting methods in multi-type demand forecasting.
Together, these innovations offer theoretical insights, empirical validation, and practicalsolutions for scalable, efficient, and equitable transportation management. Experiments onreal-world datasets confirm consistent gains in both accuracy and speed, culminating in acohesive framework that enhances the scalability, robustness, and responsiveness ofspatial–temporal traffic forecasting in ITSs
Wellbeing, Belonging and the Emotional Dynamics of Social Exclusion in Primary School
No full textIt is widely recognised that positive peer relationships enhance children's social development and are instrumental in promoting their health, adjustment, and academic success. Conversely, negative peer relationships can significantly impede a child’s social development, academic learning, and overall social and neurobiological well-being. One prevalent and hostile form of negative peer relationships is the feeling of being socially excluded or ostracised by peers. According to the Organisation for Economic Co-operation and Development (OECD) report published in 2019, an average of 9% of students across OECD member countries reported experiences of deliberate exclusion. In other words, close to one in every 10 students, across OECD member countries are subjected to this kind of social harm.
In contrast to many previous studies that have focused on investigating the perpetrators of social exclusion, for example, their motivations, this thesis focuses on the emotionally felt experiences of victims, with special reference to Australian primary schools and beyond. This study posits that social exclusion is not only a social harm; at the level of individual persons, it constitutes an existential harm that inflicts neurobiological damage on its victims. Some previous studies have provided generalised accounts of the pain endured by victims of social exclusion, as evidenced by their self-reporting. However, by adopting a multi-modal approach that gathers and analyses self-reported survey data alongside and together with electroencephalogram (EEG) data, this thesis pushes past the generalised notion of pain evoked by social exclusion, to provide a more nuanced account of the emotionally felt experiences of victims, especially how these experiences correlate with children’s feelings of emotional wellbeing and sense of belonging within the school environment.
A novel conceptual framework was developed to investigate the existential experience of social exclusion, drawing upon contemporary neuroscientific insights concerning the embodied, socially, and culturally embedded predictive Bayesian brain. This framework, which is consistent with the neurobiology of the brain as a dynamic, complex system, incorporates the notion of ‘here-and-now’ ‘feedback loops’ that operate at the intersection of the predictive, embodied brain and immediate contexts. By incorporating EEG and Event-Related Potential (ERP) technology into the research design, this study was able to investigate both the conscious but also, and significantly, the subconscious impacts of social exclusion in schools. It is believed that this begins to bridge a significant gap in the existing literature, which currently offers little insight into the conscious and virtually nothing regarding the subconscious impacts of social exclusion on students’ well-being and sense of belonging.
The empirical data garnered by this study not only corroborates much previous research showing that when being introduced to a group of similar-aged children, children exhibit an emotional desire to be accepted and to feel they belong within the new community. It provides significant, though provisional, evidence that real-time neural processes significantly correlate with a child’s self-reported responses regarding immediate distress from social exclusion, and with their sense of school belonging. Moreover, a strong sense of belonging to one’s own school acts as a protective factor, enhancing emotion regulation and reducing distress when threatened by an unknown peer’s rejection. In providing a more nuanced and comprehensive account of the experience of social exclusion that is hitherto unavailable in the literature, the findings of this study will go some way toward a better-informed platform for developing effective social exclusion intervention practices in Australian primary schools and beyond
Personal e-scooter ownership and use: Perspectives from New Zealand
No full textIn common with much of the world, e-scooters have emerged
onto the urban landscape in New Zealand, promising both a
practical and greener form of personal mobility. While focus
has primarily been around managing shared e-scooter services,
relatively liberal e-scooter legislation has encouraged the
purchase of personal/private e-scooters, which are not
regulated at the point of sale, exacerbating concerns around
how to safely accommodate this emerging mode. In turn, this
highlights the need for better understanding of personal e-scooter users, about which relatively little is known. Drawing from a survey of 252 current and former e-scooter owners in
New Zealand, this paper provides estimates of e-scooter
ownership, explores motivations for purchasing e-scooters,
who is buying them, what consumers are looking for, how they
are being used and implications for shared e-scooter schemes.
Results suggest around 60% of personal e-scooters are capable
of travelling about the maximum ‘safe’ e-scooter speed limit in
New Zealand of 25 kph. E-scooter owners are more likely be
male, middle-aged, middle/higher income, employed and have
tried a shared e-scooter scheme prior to purchase and be
motivated by the flexibility, performance, and potential cost-savings. The growing number of shared e-scooter services is evidently providing a pathway to purchase, a complementary
mode and potentially a factor in people selling their e-scooter.
Going forward, safely accommodating, and regulating e-scooter usage without compromising the intrinsic appeal of this emerging mode of transport is essential, if it is to play a meaningful role in moving us towards more sustainable mobility systems
Ventricular arrhythmias: Biomarkers, mechanisms and therapeutic implications
No full textVentricular arrhythmias (VA) are a major contributor to sudden cardiac death (SCD), cardiovascular morbidity and healthcare utilisation. The vast majority of VA are due to structural heart disease (SHD) including ischaemic and non-ischaemic cardiomyopathy (NICM). The past 50 years have seen advances in the treatment of SHD, including revascularisation for ischaemia and medical therapies for heart failure. These have reduced the global burden of SCD; however, this decline has plateaued in recent years, leaving an unresolved population that still experiences VA.
Attempts to identify patients with SHD at highest risk for VA have been based on mechanical markers of left ventricular function which neglect the subtleties of arrhythmogenesis. In SHD, the complex interplay of scar and viable myocardium results in slow conduction and creates a substrate that is vulnerable to re-entry and VA. VA and SCD can occur with only mild systolic impairment and conversely may never occur even in advanced heart failure. Thus, to better identify patients at high risk for VA, it is imperative to better understand the substrate, its architecture and underlying causes.
In this thesis, we aim to advance our understanding of the substrate for VA in ischaemic and non-ischaemic disease processes using multiple modalities. We begin by exploring the yield of coronary assessment in patients presenting with sustained monomorphic ventricular tachycardia (VT), driven by the dogma that acute ischaemia is a trigger for VA. We then develop a large animal ischaemia-reperfusion injury model to better understand the contemporary post-infarct scar architecture using a combination of cardiac imaging and electroanatomic mapping (EAM). Using this model, we also aimed to determine an optimal pacing strategy for uncovering substrate that is vulnerable to re-entry. Finally, we explore the genetic underpinnings of VA and heart failure outcomes in LMNA cardiomyopathy, one of the most malignant phenotypes of NICM
Managerial Learning from Conversations with Analysts in Conference Calls
No full textThis thesis investigates how managers learn from analysts through direct communications in
conference calls, with focus on how limited managerial attention shapes this learning process. While
prior research documents that managers learn from external signals, relatively little is known about
how they learn and prioritise more granular information provided by analysts. By examining the direct
communication between managers and analysts during conference calls, this study provides
evidence that managers incorporate analysts' forecasts and topical alignment into guidance
decisions, following the interactions.
Central to this study is the notion that managers, constrained by limited attention, rely on thematic
signals to filter and assimilate relevant information received from external sources. Using Latent
Dirichlet Allocation to identify the topics embedded in conference call conversations, this study constructs a measure of how closely the focal analyst issuing the revision aligns thematically with
other analysts.
The findings reveal that while managers learn from analysts' forecast revisions, the extent of the
learning increases when the focal analysts' topical interests align with peers. Managers find it easier
to recognise the salience of those signals and integrate them into their subsequent guidance
decisions. The attention-driven filtering is more pronounced when analysts convey bad news,
possess relative industry knowledge, or when managers are in stronger demand for external
information.
Overall, this thesis provides direct evidence that managerial learning depends not only on the
inherent nature or quality of the information but also on the selection of information bounded by
managers' limited attention. By emphasising how managers identify, prioritise and respond to
analysts' insights, this study provides novel evidence of the cognitive mechanics underlying the
learning process and highlights the role analysts play in corporate decision making
Zwitterionic Surface Modification via Plasma Immersion Ion Implantation to Improve the Safety and Longevity of Blood-Contacting Medical Devices
No full textBlood-contacting medical devices are central in the treatment of many diseases but remain limited by inadequate material biocompatibilities, driving responses such as thrombosis or inflammation that commonly catalyse device dysfunction and threaten patient safety. A promising solution involves modifying the surface chemistry with biocompatible moieties, enabling both mechanical and biological competence. Zwitterionic molecules are an outstanding candidate for surface modification due to their superhydrophilicity that thermodynamically disfavours protein adsorption. Employing plasma immersion ion implantation (PIII) to facilitate grafting may offer an effective, versatile, and scalable platform. Thus, this thesis explores the use of PIII as a linker-free method for the surface modification of medically useful polymers with zwitterionic grafts to create blood-compatible materials.
A model zwitterion (sulfobetaine, SB) was grafted to a model hydrophobic polymer (polyurethane) via PIII treatment, generating a near-superhydrophilic interface (12.98° ± 1.43°) with zwitterionic chemistries (indicated by the presence of -SO3- and -N+), without compromising the bulk tensile or flexural mechanical properties. Grafting was also effective on a range of other organic materials. Optimisation studies were performed to augment graft stability, such as integrating a crosslinker to achieve low molecular mobility. This protocol was demonstrated to limit various adverse biological responses, such reducing fibrinogen adsorption by 88%, thrombosis by up to 80%, TNF- expression by 17%, M1 macrophage differentiation by 50%, and calcification by 83%. Finally, the protocol was applied to tubular and valvular geometries, with the latter demonstrating effective treatment without affecting hydrodynamic performance.
Collectively, this thesis presents a promising advance towards creating increasingly blood-compatible medical devices, facilitating progress towards safer and more durable devices
Exploring the relationship between mental health and sleep in elite/pre-elite Australian athletes
No full textOver the past 15 years, there has been growing research attention on mental health and sleep in elite athletes. This research growth in mental health and sleep for elite athletes is exemplified by consensus statements on both topics published by prominent sporting organisations such as the International Olympic Committee. Research in elite athletes has either focused on mental health or sleep, however, little is known about the relationship between mental health and sleep in elite athletes. It is well established that mental health and sleep have a strong, bi-directional relationship within the general population, this relationship has not been confirmed in elite athletes. Therefore, this PhD thesis used a combination of mixed method approach to address two overarching aims: 1) explore the relationship between mental health and sleep in Australian elite/pre-elite athletes; and 2) design, implement, and evaluate the effectiveness of a pilot intervention aimed at improving athlete’s sleep and/or mental health. This PhD thesis sought to address an identified research gap on the relationship between mental health and sleep in elite athletes. Using mixed methods research, that then informed the identification and development of a pilot CBT-I intervention, this thesis has shown that mental health and sleep has an important relationship for elite/pre-elite athletes in Australia, and that this relationship has important implications related to athlete wellbeing, physical health, and performance