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Synthesis study of size-controlled noble metal nanoparticle systems of Re, Ir, and Os using AOT-reverse microemulsion based methodologies
No full textThis thesis presents a novel methodology for synthesizing stable, very small nanoparticles (NPs) of rhenium (Re), iridium (Ir), and osmium (Os) using a reverse microemulsion (AOT-ME) system, with AOT as the negatively charged surfactant to form and stabilize the MEs. These noble metals are among the least studied in their NP form, making this research a valuable contribution to the field.
An important initial finding was the identification of a sulfite ion impurity in commercially sourced AOT, most likely introduced during industrial preparation. The reason for the apparent ability of AOT to reduce certain metals, such as Re, was previously unknown among researchers. Although this impurity is present in low concentrations, it became significant when larger quantities of AOT were used to stabilize ME systems, acting as an unintended/hidden reducing agent. While purification with activated carbon could reduce the impurity, it came at a considerable cost of the AOT reagent.
Using the AOT-ME system, Re, Ir, and Os NPs were successfully synthesized under ambient conditions with precise control over size and size distribution. Systematic investigation of synthesis parameters—including the water-to-surfactant concentration ratio (W factor) and temperature—revealed that these factors had a significant impact on NP size and stability. Across all three metals, the effect of the W factor was consistent, with higher W values generating larger, more polydisperse particles. While the AOT-ME system effectively maintained colloidal stability and controlled particle size for all three metals, it also played a specific role in slowing the tendency of Re NPs to oxidise into perrhenate.
A range of advanced characterization techniques, including UV-Vis spectroscopy, ESI-MS, FE-SEM/EDX, and HR-TEM, were employed to thoroughly analyse the synthesized NPs. UV-Vis confirmed the successful reduction of the metal precursors, while FE-SEM/EDX provided valuable information on surface morphology and elemental composition. HR-TEM offered detailed insights into the size and crystallinity of the NPs. Additionally, ESI-MS helped investigate the chemical stability of the colloidal aqueous solutions.
This thesis contributes to the field of noble metal NP synthesis by offering a reproducible method for controlling NP size and stability within AOT-ME systems. The findings provide valuable insights for optimizing synthesis protocols and broaden the potential applications of Re, Ir, and Os NPs in catalysis and materials science
Pruning feature extractor stacking for cross-domain few-shot learning
No full textCombining knowledge from source domains to learn efficiently from a few labelled instances in a target domain is a transfer learning problem known as cross-domain few-shot learning (CDFSL). Feature extractor stacking (FES) is a state-of-the-art CDFSL method that maintains a collection of source domain feature extractors instead of a single universal extractor. FES uses stacked generalisation to build an ensemble from extractor snapshots saved during target domain fine-tuning. It outperforms several contemporary universal model-based CDFSL methods in the Meta-Dataset benchmark. However, it incurs higher storage cost because it saves a snapshot for every fine-tuning iteration for every extractor. In this work, we propose a bidirectional snapshot selection strategy for FES, leveraging its cross-validation process and the ordered nature of its snapshots, and demonstrate that a 95% snapshot reduction can be achieved while retaining the same level of accuracy
Assessing the viability of foldable-expandable container homes for post-disaster housing in New Zealand
No full textNatural disasters frequently demolish New Zealand, with its diverse landscapes. It is particularly susceptible to various natural disasters due to its unique geological position on the edge of the Pacific Ring of Fire (McKinnon, Scott, and Margaret Cook, 2020). This makes it prone to earthquakes, volcanic activity, tsunamis, and extreme weather events. A notable example of such a disaster is Cyclone Gabrielle, which struck the Hawke's Bay region in New Zealand. It creates wide damage in housing properties, leaving damaged bridges and culverts, buried roads, significant dropouts, and isolated communities in its wake. One of the major difficulties for government authorities and policymakers is to build houses for the victims of such natural disasters within as short a period as possible. The rapid provision of safe, durable, and affordable shelters is essential to restore a sense of normalcy for affected populations. Traditional reconstruction methods are often slow, expensive, and complex, particularly in regions with limited resources or logistical challenges. This has led to the exploration of alternative housing solutions, such as the use of modified shipping containers.
In New Zealand, as it is a reality, expeditious and resilient housing options are crucial for recovery after a natural disaster. Therefore, strategic solutions should be introduced to assist the responsible entities and agencies in providing shelters to the disaster victims within a short duration.
Container homes offer a unique combination of structural integrity, portability, and affordability, making them an attractive option for post-disaster housing. Their inherent durability allows them to withstand harsh environmental conditions, and their modular nature facilitates quick assembly and scalability. Additionally, container homes can be prefabricated and easily transported to disaster sites, reducing the time required for construction and enabling immediate relief efforts. This thesis explores the feasibility of using double-wing expandable foldable container homes as an innovative post-disaster housing solution in New Zealand, focusing on the aftermath of Cyclone Gabrielle in Hawke's Bay.
Findings indicate that container homes offer significant advantages, including reduced construction timelines, cost savings, and the adaptability needed for fast recovery in disaster-affected regions. However, challenges remain in achieving compliance with New Zealand’s stringent building codes and in adapting the homes to withstand several factors such as seismic/ wind resistance, waterproofing, etc. which are prevalent in many disaster-prone areas. Regulatory requirements, such as PS1 and PS4 design approvals and local council consents, emerge as pivotal considerations that can delay deployment if not streamlined
Full-scale experimental study on the stability of chords of cold-formed steel c-section roof trusses
No full textThe use of cold-formed steel (CFS) roof trusses is growing as a substitute for wood because of their advantages in quick fabrication, high strength-to-weight ratio, and lightweight nature [1]. However, the torsional buckling behaviour of these trusses remains inadequately understood. There have been experimental studies conducted for the behaviour of CFS roof trusses [2], wide-span roof trusses [1] and small-scale roof trusses [3]. The common failures in the previous studies of CFS roof trusses include distortion of heel plates, local buckling of the top chords [3] and flexural-torsional buckling becoming a concern in elevated temperatures [4]. The behaviour of CFS under loads applied away from the shear centre requires more testing due to its thin nature.
Through eight full-scale experiments, different truss configurations (back-to-back and linear), different lateral restraint spacing and internal support inclusions, this study investigates the structural behaviour of lipped channel (C-section) chords in CFS Howe roof truss assemblies. The experimental total load at failure exceeds factored predicted capacities by 12% and 34%, and factored design capacities by 34% and 60%, depending on lateral restraint spacing. Design equations, however, are conservative with predicted-to-experimental capacity ratios as low as 0.7 for wider spaced lateral restraints and 0.5 for closely spaced restraints. In 37.5% of cases, the design standards fail to predict the correct failure modes.
Observed failures during the experiments include lateral-torsional buckling, out-of-plane buckling, and inward torsional buckling. The single-channel linear truss system (face of web connected to back of chords) proved more robust than back-to-back system (back of web connected to back of chords), offering better torsional restraint and load-bearing capacity post-failure. Truss strength is enhanced by increased lateral restraints, but current design standards lack provisions for calculating member lengths with such restraints. Therefore, further research, including FEM analysis, is needed to address this gap and improve design accuracy
Human–AI friendship is possible and can be good
No full textThis article argues that human–AI friendships are possible and, in some current and many future contexts, can be valuable—both for the humans participating in them and for the wider society in which such friendships exist. To begin, the article discusses some weaknesses in existing conceptions of friendship, including the theories of friendship commonly applied to human–AI relationships. It proposes a flexible conception of friendship that avoids these weaknesses. The article then analyzes the main objections to human–AI friendships being either possible or good—that humans cannot see AI as their friends; that these friendships are not good because they are unequal; that AI lack the capacity to be a friend; and that human–AI friendships displace (more valuable) human–human friendships. It argues that each of these objections fails to withstand critical scrutiny. In some cases, the analyses also amount to a rejection of existing views of friendship that require what are taken to be unnecessary features. Having dealt with these objections, the article shows that human–AI friendship is possible on the more flexible conception of friendship. It then provides some evidence that human–AI friendships can be good, such as by providing human users with the experience of being emotionally supported. The article also notes some practical concerns about the ways human–AI friendships might proliferate and the moral responsibilities that might accrue to governments and corporations accordingly. The article concludes that the new view of friendship means the value human–AI friendship should be re-evaluated as possible and potentially valuable today and in the future
Transforming data ecosystems in Aotearoa New Zealand: a landscaping report undertaken as part of the Tikanga in Technology project
No full textHapū data sovereignty: Tips for getting started
No full textThis brief is a part of a series, produced for the Tikanga in Technology (TiNT) research programme, that provides a hapū perspective on data sovereignty, data governance, and data privacy. The purpose is to provide practical advice for individuals, whānau, marae and hapū who are embarking on their own hapū data sovereignty kaupapa, with a particular focus on whakapapa data
Axial capacity of face-to-face built-up aluminium alloy columns: Numerical simulation and design proposal
No full textIn recent years, aluminum alloy has seen increased use in construction due to its exceptional corrosion resistance and mechanical strength, especially in structural elements like channel sections, hollow pipes, and angles. Cold-formed aluminum alloy face-to-face (CAAFTF) built up channel sections with web holes or without web holes have emerged as a significant development in the construction industry, focusing on streamlining the installation of plumbing and electrical services as well as Glass walls in front of buildings. Previous research indicated that these aluminum alloy sections were studied on bending capacity with web holes and found the bending modified formula for plain webs as well as the web with perforated sections. However, no comprehensive study has been reported in the literature for such aluminum alloy built up face to face columns subjected to compression.
This study investigates the axial compression behaviour of aluminium alloy columns with perforated webs, focusing on the influence of screws and perforations on axial capacity. A numerical analysis was conducted on screw-fastened, perforated, face-to-face built-up aluminium alloy channel sections under axial compression. The finite element (FE) model developed using abaqus was validated against 29 experimental results from the literature. The validated nonlinear elasto-plastic FE model was then extended to analyse 495 parametric FE models to examine the effects of key parameters, including modified slenderness, screw number, number of web holes, hole diameter, and section thickness, on the axial strength.
The parametric analysis revealed a reduction in axial strength by approximately 8% for every 0.2 increment in the diameter-to-web width ratio (a/h). Axial strength results from experimental tests and FE analysis were compared with current design guidelines in the Australian/New Zealand Standards (AS/NZS 4600). The analysis showed that AS/NZS design strengths were overestimated by 15% for single perforated webs and underestimated strengths by 12% for multiple perforated web sections but AS/NZS estimation for plain section is more closely match with experimental results.
A new strength reduction factor equation was developed for aluminium alloy face-to-face built-up channel sections with single and multiple perforated webs. Reliability analysis confirmed the accuracy of the proposed equation, which is applicable within specific limits of slenderness ratio, web width-to-length ratio, and web width-to-thickness ratio. The findings indicate that introducing perforations reduces the axial capacity of plain sections by 8% to 16% for single and multiple perforated webs, respectively. This study provides valuable insights for the design and optimization of aluminium alloy built-up sections with perforated webs
Unveiling the layers of educational reform: A critical realist analysis of the ideation, development and enactment of the Philippine professional standards for teachers policy
No full textThis study investigates changes in teacher professionalism in the Philippines in response to globalising education policies, with a particular focus on the impact of the 2017 Philippine Professional Standards for Teachers (PPST) policy introduced under the conditions of official development assistance. With the technical and financial support of the government of Australia, this policy introduces clear indicators of professional competence that challenge traditional views of teacher professionalism and redefine teacher quality. Anchored by the ontological and epistemological foundations of critical theory and critical realism, and the theoretical and methodological framework of the Critical, Cultural Political Economy of Education (Dale & Robertson, 2015), this study explores the underlying mechanisms that have shaped the ideation, development and enactment of the professional standards policy and its impact on teacher professionalism.
Based on interviews with policymakers, Department of Education (DepEd) officers, a public school district supervisor, school heads and teachers, the findings of the study indicate the emergence of idealised professionalism, a term used to describe how the context and policymaking process of the professional standards policy was heavily influenced by broader economic, political, and cultural globalisation. However, this idealised professionalism remains primarily a theoretical construct that is not grounded in the actual realities of teaching in the Philippines. The introduction of the policy has resulted in ongoing tension between state regulation and teachers’ professional autonomy. This tension is further complicated by the fact that policy enactment is not always consistent across different schools and jurisdictions, with various cultural practices and contextual socio-economic factors shaping teachers’ agentic responses. Ironically, the institutionalisation of clear expectations for teachers embodied in idealised professionalism has led to teaching practices characterised by complexity rather than certainty.
This study makes a contribution to the continuing debate over the role of official development assistance in driving education policies that not only perpetuate neoliberal and neocolonial practices but also fail to align with the local context of aid-receiving countries. It prompts critical reflection on whose interests are ultimately served by externally induced official development assistance project reforms in developing countries.
The study recommends redirecting official development assistance towards areas of government where its benefits would be maximised, such as institutional building and capacity development, rather than project-based reforms. Additionally, establishment of a mechanism for local school stakeholders and the local community to actively participate in national policymaking could help ensure that policies are appropriate and relevant to teachers. Lastly, future studies could re-narrativise the globalisation story by concentrating on local contexts and using them as the vantage point from which to better understand the modernisation of education
Enhancing athletic performance: Can video modelling and feedback on forehand hitting increase passing accuracy of field hockey players?
No full textResearch in applied behaviour analysis and sports performance is becoming more evident in sporting environments. I aimed to explore the effectiveness of video modelling (VM), and video modelling combined with feedback (VF), and whether combined video modelling and video feedback (VM+VF) is an effective coaching tool to teach and improve athletes’ skill accuracy. A single subject multiple baseline design across participants was used. Four male field hockey players, who were all members of the same North Island National U18 team, took part in this study. The intervention had three phases: beginner-level video modelling; intermediate level video modelling; intermediate video modelling + video feedback. Participants watched a short instructional video and then practiced their forehand hitting in a structured practice session which was videotaped. Both video modelling conditions were effective, but the most performance gains were seen in Phase 3 where video feedback was added. All the participants showed an increase in the number of successful forehand hits after being exposed to VM and VM+VF, supporting the effectiveness of the intervention. These findings add to the existing body of work that supports the use of applied behaviour analysis techniques in sports training. Video modelling and video feedback may be useful for enhancing skill execution in field hockey. Further research should be conducted to determine the long-term retention of these skills and the usability of similar interventions for other technical aspects of field hockey and other sports