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Exploring the relationship between age and victimisation risk
(The University of Waikato, 2026) Steer, Donelle; Tompson, Lisa
Extensive research has examined the relationship between age and offending, which is reflected in the established age-crime curve. The age-crime curve shows that offending typically rises during adolescence, peaks in late adolescence, and declines through the twenties and beyond. But less attention has been given to investigating age-related patterns of victimisation. Therefore, in this thesis we1 sought to answer two research questions. First, is there an age-victimisation curve comparable to the well-established age-crime curve? Second, if present, does the age-victimisation curve differ across broad crime categories (property vs interpersonal crime)? To answer these questions, we analysed data from two main sources – the New Zealand Recorded Crime Victims Statistics (RCVS) and the New Zealand Crime and Victims Survey (NZCVS). We plotted both the frequency and rates of victimisation across age using line graphs. For both our research questions, we found that there were age-victimisation curves that mirrored the age-crime curve for the RCVS samples, but not necessarily for our NZCVS samples. Generally, our research showed that the rate and frequency of victimisation increases from teenage years well into people’s twenties, before decreasing as age increases. However, the NZCVS samples showed a gradual decline rather than a discernible curve, with some spikes around middle adulthood. Future research should use longitudinal data to better understand the distribution of victimisation over the life-course and examine the age of onset of victimisation to inform targeted prevention and intervention efforts.
How can we make a diverse range of aromatic sulfates to explore sulfatase substrate relationships?
(The University of Waikato, 2026-05-16) Wang, Peiyao; Dickson, Benjamin
Antibody–drug conjugates (ADCs) are an emerging class of targeted therapeutics that combine the high specificity of monoclonal antibodies (mAbs) with the potent cytotoxicity of small-molecule drugs. A critical component of ADC design is the linker between mAbs and payload, as its chemical stability and cleavage behaviour directly determine therapeutic efficacy, selectivity, and safety. While peptide-based cleavable linkers dominate current clinical ADC platforms, their susceptibility to premature cleavage and instability in certain biological contexts has motivated the exploration of alternative enzymatically cleavable linkers. Arylsulfatase-cleavable linkers have recently attracted increasing interest as a promising alternative due to their excellent efficiency and reported stability in both human and mouse plasma. The cleavage of sulfate is catalysed by lysosomal sulfatases. Sulfatases were expressed in some tumour environments, which further support the selectivity of ADCs. However, systematic study for the characterization of structure and the analysis of properties is still insufficient, which limited the development of sulfatase-cleavable linker in certain degree. In this study, a diverse library of substituted aryl sulfates was synthesised to probe sulfatase–substrate interactions and to establish a robust analytical framework for their characterisation. The synthetic strategy enabled the preparation of aryl sulfates bearing a range of electron-donating and electron-withdrawing substituents at different positions on the aromatic ring, allowing systematic evaluation of electronic and structural effects. The resulting compounds were fully characterised using nuclear magnetic resonance (NMR), high-performance liquid chromatography (HPLC), mass spectrometry (MS), and UV–visible (UV–Vis) spectroscopy.
Process integration and electrification with digital twins
(The University of Waikato, 2026-05-14) Lincoln, Benjamin James; Walmsley, Timothy Gordon; Atkins, Martin John; Walmsley, Michael R.W.; Young, Brent R.
The decarbonisation of industrial process heat is one of the most pressing challenges in the global energy transition. In New Zealand, fossil fuels remain the dominant source of process heat, despite having over 80% renewable electricity generation. Milk powder production is a major consumer of process heat, with evaporation and drying processes relying on large amounts of coal- and gas-fired steam. Electrification technologies such as industrial heat pumps and mechanical vapour recompression (MVR) have the potential to significantly reduce emissions, yet widespread adoption has been limited because of the complex interactions between heat and power, in addition to uncertainties around practicality. Conventional process integration (PI) techniques were designed for fossil-fuelled utilities and are poorly aligned with the work requirements and integration constraints of electrification. Meanwhile, legacy simulation tools are ill-suited to the complex fluids and system interactions of food and dairy processes. This thesis addresses these gaps by developing a generalisable Process Integration and Electrification (PI&E) methodology that combines exergy-based targeting, retrofit strategies, and techno-economic evaluation coupled with an iterative design-centric digital twin framework. The thesis is structured in two parts. Part A develops the digitalisation foundations, including the preparation of a milk evaporation case study, the creation of advanced thermophysical property packages for complex fluids (milk, refrigerants, humid air), and the construction of a design digital twin using both commercial and open-source platforms. Part B applies the digital twin to PI&E, integrating operational optimisation, Exergy Pinch Analysis, and systematic evaluation of electrification technologies in both greenfield and retrofit contexts. For greenfield design, the research extends Pinch Analysis principles to heat pump integration by utilising heat pockets to create multiple Pinch points, enabling systematic minimisation of temperature lift and improved integration opportunities. Building on this, an iterative PI&E design workflow was developed to guide technology placement and evaluate electrification pathways. This culminated in the design of a novel fully electric milk evaporator system that achieved a specific electricity consumption of 120 kWh per tonne of milk powder, compared with 159 kWh/tp for a simpler single heat pump design, demonstrating higher efficiency. For retrofit applications, the thesis advances PI&E by extending heat pump bridge analysis to explicitly include process unit heat flows, allowing process modifications to be considered alongside heat exchanger reconfiguration. This innovation addresses a key gap identified in previous literature, enabling more retrofit strategies. The method was demonstrated through multiple related case studies of milk evaporator plants, producing a set of common retrofit solutions. These include replacing thermal vapour recompression (TVR) and/or direct steam injection with MVR systems, which were shown to deliver lower levelised costs of heat compared with reference boiler-based designs. The culmination of the research is a unified PI&E methodology that combines digital twins, rigorous thermodynamic analysis, and practical integration strategies. The results show that electrification of milk evaporation systems can be achieved in both new and existing plants with significant efficiency gains and competitive economics. PI&E has been tested across multiple platforms: Aspen HYSYS, DWSIM and the Ahuora Digital Twin Platform, powered by IDAES – proving to be a platform-agnostic, yet digitalisation-centred, methodology. Although developed and applied in the context of New Zealand’s dairy sector, the methods and insights are broadly transferable to other low- to medium-temperature process industries, offering a robust and scalable pathway to accelerate industrial decarbonisation.
Valorisation of waste mussel shells and harakeke fibres for enhanced performance in polypropylene composites
(The University of Waikato, 2026) Xu, Jing; Mucalo, Michael R.; Pickering, Kim L.
This doctoral research develops high-performance, environmentally sustainable polypropylene (PP) composites by valorising low-value biogenic waste. Within a Circular Economy framework, it addresses challenges in plastic sustainability and the need for bio-based alternatives by utilising mussel shells (MS), an aquaculture by-product, and harakeke fibres (HF, Phormium tenax), derived from agricultural waste, as reinforcing materials. Through systematic characterisation, surface modification, filler hybridisation, and multi-scale evaluation, this study demonstrates the successful transformation of these biogenic low-value resources into functional reinforcements for PP. The structural and surface properties of MS-derived fillers were first investigated, focusing on functionalization with a mussel-inspired polydopamine (PDA) coating. Solid-state nuclear magnetic resonance (SS-NMR) and Fourier-transform infrared spectroscopy (FTIR) confirmed PDA formation, revealing its indole/indoline units and quinonoid groups. X-ray diffraction (XRD), SS-NMR, and FTIR showed that MS contains calcite and aragonite phases, which remain intact after coating. Thermogravimetric analysis (TGA) confirmed the thermal stability of MS, slightly improved by PDA, while X-ray photoelectron spectroscopy (XPS) verified successful coating deposition on MS fillers via nitrogen-containing groups. Surface energy analysis revealed that PDA coating increased MS filler hydrophilicity, whereas maleic anhydridegrafted polypropylene (MAPP) treatment particularly when combined with PDA enhanced filler hydrophobicity, establishing PDA/MAPP co-modification as an effective strategy to improve filler interaction with the hydrophobic PP matrix. Polypropylene (PP) composites reinforced with pristine, maleic anhydride-grafted polypropylene (MAPP)-modified, and PDA/MAPP co-modified mussel shell (MS) fillers were systematically compared with neat PP to assess thermal and mechanical performance. Thermogravimetric analysis (TGA) revealed improved thermal stability across all composites, most notably with PDA/MAPP-MS. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed that MAPP and PDA/MAPP surface treatments enhanced nucleation and crystallinity, promoting -crystal formation in the PP matrix. Mechanical testing showed that unmodified MS reduced tensile and flexural strength, an effect mitigated by MAPP modification. PDA/MAPP co-modification yielded the greatest improvements, with tensile strength, flexural strength, and modulus all significantly enhanced at 40 wt.% loading. Dynamic mechanical analysis (DMA), creep recovery, and melt rheology further supported the advantages of PDA/MAPP comodification, consistent with scanning electron microscopy (SEM) observations of improved interfacial bonding. The study further explored hybrid reinforcements combining MS with HF. Crystalline structure analysis showed both fillers acted as nucleating agents, with hybrid systems producing higher crystallinity than neat PP. XRD confirmed the co-existence of - and -crystals. Composites with 10% MAPP-MS/30% HF and 10% PDA/MAPP-MS/30% HF showed the highest -phase content (17.32% and 16.71%, respectively), enhancing toughness and elongation while retaining strength and stiffness. SEM backscattered electron (BSE) analysis confirmed improved fibre matrix adhesion and polymer bridging, while energy-dispersive X-ray spectroscopy (EDS) mapping showed uniform filler distribution. These hybrid systems outperformed single-filler composites, with 10% MAPP-MS/30% HF achieving a 48% increase in tensile strength over neat PP. DMA confirmed a higher storage modulus, improved energy dissipation, and better adhesion. Creep-recovery tests demonstrated greater dimensional stability, particularly for the 10% PDA/MAPP-MS/30% HF system. Melt rheology behaviour suggested the formation of a hybrid filler network that further restricts chain mobility. Finally, composites with 5% PDA/MAPP-MS fillers demonstrated superior UV stability. After 1,000 hours of accelerated weathering, neat PP exhibited cracking, roughening, and discolouration, while PDA/MAPP-MS composites retained smooth, intact surfaces. FTIR confirmed their lowest carbonyl index increase, reflecting suppressed photo-oxidative degradation. XRD and DSC showed a stable crystalline structure, and mechanical testing revealed only a 15.6% tensile strength loss, compared to 62% for neat PP. DMA further confirmed superior viscoelastic stability. These results indicate dual protection: MS act as UV shield, while PDA scavenges free radicals to delay degradation. Overall, this research establishes mussel shell and harakeke fibre as sustainable, high-performance reinforcements for PP. PDA/MAPP co-modification and hybridisation strategies optimise filler matrix interactions, yielding composites with enhanced thermal, mechanical, rheological, and weathering properties. These findings highlight the potential of low-value biogenic fillers for sustainable, durable, and environmentally resilient composites.
The investigation of military style academies as an intervention for young people with serious and persistent criminality
(The University of Waikato, 2025) Kazadi, Mujinga Deborah; Roen, Katrina
A developmental perspective asserts that criminal trajectories arise due to the complex interactions between environmental factors and individual factors increasing vulnerabilities towards persistent criminality. These criminal trajectories are identifiable during early childhood and represent unaddressed vulnerabilities across social, cognitive and familial contexts. The presence of serious and persistent offending amongst young people is significant because it highlights the accumulative effects of risk factors present in childhood and places them at increased risk of transitioning into persistent criminality in adulthood. It is therefore advantageous to design interventions targeting serious and persistent offending in young people. Aotearoa’s National government proposed military style academies (MSAs) as an intervention to reduce the amount of young people involved in serious and persistent offending. The combination of physical activity and rehabilitative components is proposed to alter criminal trajectories and encourage desistance from crime. This thesis investigates youth practitioner’s perceptions of MSAs, an intervention for youth with serious and persistent criminality to conceptualize how youth rehabilitation can be shaped to positively contribute to the wellbeing of Aotearoa’s most vulnerable young people. Reflexive thematic analysis was used to analyse 11 interviews with youth practitioners with at least one year’s experience working with vulnerable youth. Four main themes and nine sub-themes were identified. The four main themes included addressing the root causes of crime, reducing re-offending, cultural considerations and the juvenile justice system. Serious and persistent offending amongst young people was viewed to be the result of a lack of early interventions targeting those at the highest risk of developing enduring criminal identities. The whānau unit was highlighted as a key target for early interventions and rehabilitative programmes. Participants raised concerns about the incongruence between MSAs and a Te Ao Māori world view. Participants suggested that MSAs failed to recognise the extent to which young people who offend are often victims first. Further, they argued that MSAs did not facilitate reintegration into the community. These factors were associated with increasing the likelihood that young people will go on to offend. These findings support the need for interventions to embrace a therapeutic model emphasizing the reconciliation and redemption of the young person. As such, the re-structure of youth rehabilitation and the juvenile justice system to more closely align with Mātauranga Māori and desistance theories can be considered a robust strategy to disrupt the care to custody pipeline so prevalent in young people who offend.