ResearchSpace@Auckland
University of Auckland Research Repository - ResearchSpace
ResearchSpace is an online archive for the University of Auckland and contains full text theses and other research outputs.
University Staff: Update your Discovery Profiles and deposit full text content using Te Waka Huia Rangahau | Research Outputs.
Communities in ResearchSpace
Select a community to browse its collections.
Recent Submissions
Lanthanum Carbonate-Based Adsorbents for Low-Level Phosphate Treatment
(ResearchSpace@Auckland, 2024-07) Li, Jing; Yu, Wei; Young, Brent; Li, Bing
Phosphorus (P) pollution is a widespread environmental concern worldwide. Excessive phosphate discharge can trigger eutrophication, negatively affecting the aquatic ecosystems, economic development and human health. The low threshold of 0.02 mg P/L for inducing eutrophication in water bodies challenges conventional technologies to effectively remove phosphate. Adsorption technology is widely recognized for its high capacity for low-level phosphate removal. However, the reduced adsorption capacity of adsorbents at low phosphate concentrations results in high costs, posing an impediment to the control of eutrophication.
This project aims to develop lanthanum (La) carbonate-based adsorbents suitable for low-level phosphate removal. Indeed, La carbonate exhibited an excellent adsorption capacity at low phosphate concentrations. Exploration of the adsorption mechanism revealed the importance of the ion exchange capacity of the adsorbent for low-level phosphate removal. To further enhance the adsorption capacity and reduce costs, the Fe modification strategy was proposed. It was demonstrated that the conversion of Fe(II) to Fe(III) during the synthesis process could transfer electrons to the adjacent La active site, which optimized its electronic structure and enhanced electron transfer between phosphate and La, thereby facilitating phosphate adsorption. Additionally, Fe modification also enhanced the adsorbent's resistance to dissolved organic matter in real water due to the weaker coordination ability of Fe than La. Further, magnetic La/Fe carbonate was prepared using inexpensive magnetite as the carrier and Fe source, exhibiting the high adsorption capacity, excellent separability and low cost. The study also demonstrated that metal ligands species and amount and surface-active metal sites coverage caused a decrease in adsorption capacity of La-based adsorbents. The study clarifies the primary mechanism involved in La carbonate-based adsorbents-bound phosphate at low levels, reveals the advantages of the Fe modification strategy for phosphate removal, and provides a possible way to develop adsorbents for low-level phosphate removal.
A systematic literature review of the environmental impacts of space activities: planetary boundaries for the New Space age
(ResearchSpace@Auckland, 2024) Foo, Darcy R.; Mankelow , Cody; Dowling, Thomas
Meeting the 1.5oC global warming goal of the Paris Agreement is becoming tenuous and
six of the nine planetary boundaries, a framework outlining safe limits of anthropogenic pressure
on the environment, have been transgressed. A seventh will likely being crossed in the coming
years. The meteoric rise of the commercial space sector, dubbed New Space, is adding fuel to the
fire and is forecast to continue to grow into a $1.8T USD industry by 2035. This poses
significant environmental risk to the upper atmosphere and Earth’s orbits as space activities are
the only direct source of pollution in these areas. Operating with limited environmental
oversight, there is a tragedy of the commons unfolding which some researchers have called an
uncontrolled geoengineering experiment.
To understand the scope and scale of the environmental impacts of the New Space
economy, an iterative systematic literature review following the ROSES protocol was
undertaken. Assessing 4254 papers published over 60 years it was established that there are
environmental impacts which can be assessed using the planetary boundaries framework.
Specifically, the boundaries most at risk from New Space activity are climate change,
stratospheric ozone depletion, and atmospheric aerosol loading. Using the planetary boundaries
framework, the orbital environment was also considered due to its increasing congestion. 252
papers were given critical appraisal and 21 were included in a qualitative synthesis of the
impacts against each discussed boundary, Earth’s orbits, and the regulatory environment
governing space activities.
The findings of this review indicate that space technology has progressed much faster
than research into its environmental impacts. Indeed, knowledge of these impacts has declined
over time as the nature and intensity of activity has evolved. The emissions from rocket launches
and object re-entry into the atmosphere may have more of an impact than previously thought and
the orbital environment is becoming dangerously crowded due to mega-constellations. Crucially,
the planetary boundaries which are furthest from transgression, stratospheric ozone depletion and
atmospheric aerosol loading, are under threat from New Space activity. International
collaboration between industry and governments will be required. Regulatory overhaul and
further research into the environmental and socio-cultural impacts of New Space activity is
urgently needed.
Edge AI Application and Optimization: FPGA-Accelerated Railway Damage Detection and Progressive Quantization Framework
(ResearchSpace@Auckland, 2025) Yan, Dongwei; Ma, Sean Longyu
The increasing demand for real-time, low-power artificial intelligence (AI) applications has driven the deployment of deep neural networks on resource-constrained edge devices, such as Field-Programmable Gate Arrays (FPGAs). This thesis focuses on developing an efficient railway damage detection system using FPGA-based hardware and proposes a novel quantization framework to address the limitations posed by hardware constraints. Chapter 1 presents the design and implementation of a railway track detection system, which comprises four main components: an enhanced railway damage image dataset, an FPGA integrated with a convolutional neural network (CNN), a host computer for interaction and visualization, and an intelligent vehicle platform. The intelligent vehicle captures real-time images of railway tracks using a gimbal-mounted camera and transmits them to the FPGA for damage detection. The detection results, including track status and precise damage location, are wirelessly sent to the host computer for visualization. Although the system achieves real-time performance and low power consumption, aggressive model quantization is required to fit the FPGA’s resource limitations, which results in a reduction in accuracy. To mitigate this issue, Chapter 2 introduces a progressive quantization framework that incrementally reduces the bit-width of weights and activations while preserving model accuracy. The framework incorporates advanced techniques, including the Straight-Through Estimator (STE), Arctangent Soft Round (ASR), Minimize Discretization Error (MDE), and a filtering mechanism. It is evaluated on six neural network architectures—ResNet18, ResNet20, VGG7, VGG16, MobileNetV2, and ShuffleNetV2—using CIFAR-10 and Tiny ImageNet datasets. Experimental results demonstrate that the proposed approach significantly improves quantized model accuracy, achieving near-full-precision performance in most cases. Future research will focus on integrating the progressive quantization framework into the railway damage detection system, with the goal of balancing resource efficiency and high detection accuracy. This work provides a practical and scalable solution for deploying AI-based monitoring systems on edge platforms, contributing to real-time edge AI applications in critical infrastructure maintenance.
Along the Arahura
(ResearchSpace@Auckland, 2025) MacPherson, Bradley; Barton, Chris
Human-made climate change, population growth, and the expansion of primary industries have dramatically affected New Zealand's natural environment since the arrival of European settlers. Further to this climate change threatens human life across the planet putting pressure on countries to reduce emissions to prevent catastrophic rises in temperature. This thesis explores how future loss of land also threatens personal and collective identity. Identity; being inherently relational, relies on the external world to define itself, highlighting the existential threat to identity posed by destruction of land.
The link between land and identity is integral within a Māori world view, land is seen as being intertwined with whakapapa(genealogy) and tribal history. Kai Tahu academic Hana O'Regan, in the book Ko Tahu, Ko Au explains: "On a spiritual level the land was carved with the histories of the iwi, thus hosting not only the living but also the past, the tupuna who had gone before the tribal atua that guarded the rohe."
This link between identity and land is also present in 20th Century Modernist New Zealand Art, though rather than seeing land and individual as intertwined, artists created a fictional dialogue with landscape by applying ideas upon nature. Art historian Francis Pound critiques this lens, explaining that in viewing the landscape as a blank canvas, artists ignored existing life and culture already present within Aotearoa; Pound refers to this fiction as a "noisy silence." This research aims to engage with art and literature through a critical lens by focusing on, where identity is uncovered by viewing the land as sacred and sublime.
These shared cultural links between land and identity are explored through model making and hand drawing, culminating in a covered bridge and chapel located on the Arahura River, retelling the story of Kai Tahu's discovery of Pounamu. The project aims to highlight the threat to identity from human-created environmental erasure.
Investigating the Role of Distinct α-synuclein Strains in Different α-synucleinopathies
(ResearchSpace@Auckland, 2024-11-11) Wiseman, James Alexander; Curtis, Maurice; Dieriks, Birger Victor; Murray, Helen
α-synuclein (α-Syn) is a structurally complex protein that is central to the pathogenesis of Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), which are collectively known as α-synucleinopathies. How the pathogenic misfolding of this single protein precipitates three pathologically and clinically distinct disease phenotypes remains enigmatic. The prevailing hypothesis posits that α-Syn is capable of adopting a multitude of unique 3D conformations,
which are known as strains. These distinct strains are thought to drive the disease-specific misfolding and propagation of α-Syn in different α-synucleinopathies, giving rise to their heterogeneity. This thesis sought to comprehensively interrogate the differential biochemical properties of patient-derived α-Syn from the human brain affected with PD and MSA.
Multiplex immunohistochemistry with epitope-specific α-Syn antibodies revealed that α-Syn aggregate structures in pathologically burdened regions of the human brain with PD and MSA look dramatically different and exhibit distinct cell type-specific and subcellular arrangements. N-terminus immunolabelling identified novel populations of perinuclear, microglial, astrocytic, and neuronal lysosomal α-Syn aggregates in the human brain with PD, that are not detected by other canonical α-Syn antibodies. Multiplex immunolabelling revealed that antibodies targeting α-Syn phosphorylated at the serine 129 residue significantly underestimate the actual α-Syn pathology load across α-synucleinopathies. Biochemical analysis of α-Syn with proteinase K demonstrated that N-terminus immunoreactive inclusion structures in PD, and oligodendroglial inclusions in MSA, are more susceptible to proteolysis compared to mature PD Lewy pathology and MSA neuronal inclusions, respectively. High-resolution confocal microscopy was utilised to study the intracellular and intranuclear architecture of oligodendroglial and neuronal α-Syn inclusions in MSA and characterise their pathological maturation. Finally, seed amplification assays were used to demonstrate distinct aggregation kinetics in neuropathologically confirmed PD and MSA cases, affirming the ability of these assays to reliably discriminate between α-synucleinopathies. In addition, these data demonstrate the enhanced seeding potential of MSA patient-derived α-Syn compared to PD α-Syn.
The multifaceted investigation of α-Syn in this thesis highlights that the pathological misfolding and propagation of this protein in PD and MSA is disease-specific. It subsequently demonstrates that disease-specific α-Syn species represent distinct conformational strains. Collectively, this thesis sets the stage for more refined diagnostic techniques and, with further ultrastructural analysis of these unique α-Syn strains, provides a platform for more targeted therapeutic strategies for treating α-synucleinopathies.