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Measurement and modelling of calcium tartrate precipitation in wine.
Full text linkPrecipitates in wine are considered undesirable by the wine industry as consumers perceive them as indicators of poor wine quality. Calcium tartrate precipitation is difficult to predict and can occur months after bottling, which makes it hard for winemakers to prevent. The levels of calcium and tartrate are important for predicting the precipitation of calcium tartrate, but wine also contains many interacting components that will influence its formation and solubility in solution. Any attempts to model and predict the precipitation of calcium tartrate must account for these interactions.
A system of equations for ion equilibria, electroneutrality, and conservation of mass was solved using Newton’s Method. This used activity coefficients calculated with the mean spherical approximation method, which provides good estimates for a wide range of concentrations and neutral molecules. The model accounted for the major species present in wine, including water, ethanol, the major organic acids, inorganic anions and cations, glucose, and fructose. Automatic pH adjustment was implemented to ensure the model correctly predicted the measured pH of the wine. Heun’s method was incorporated to solve precipitation rate equations and demonstrated how a solution with a low supersaturation could suddenly form crystals after a long period.
Wines with and without crystals were analysed using high-performance liquid chromatography, ion chromatography, and microwave plasma atomic emission spectroscopy. The pH, ethanol, calcium, tartrate, and malate concentrations were individually compared for the wines that formed calcium tartrate and the wines that formed no crystals. This showed that there was no significant difference between the groups for any of these factors. However, the model was able to account for the interactions between the wine components and predicted significantly higher supersaturation ratios for wines that formed calcium tartrate. There was overlap between the groups but the model could still provide a useful indication of a wine’s risk level. A reduced model containing only water, ethanol, calcium, tartrate, malate, and lactate was tested to see how many compounds were required for an adequate prediction. This reduced model was still able to predict significantly higher supersaturation ratios for wines that formed calcium tartrate and would be more practical for winemakers to use. It was harder to do pH adjustment using the reduced model, so a sequential search was implemented to ensure that the code could solve automatically for every wine.
A range of juices and wines were analysed to see if the model could be used early in the winemaking process to predict calcium tartrate formation. No relationship was found between the supersaturation ratio of the juice and the final wine, demonstrating that the model could only be used for prediction after most of the winemaking processes were finished. Ideally, the model would be used after cold stabilisation (when potassium bitartrate is precipitated) and close to the bottling of the wine.
Some of the major factors that increase the risk of calcium tartrate precipitation are high pH, calcium, tartaric acid, ethanol, and low malic acid. These factors all interact, so no simple ranges can be given where there is no risk of precipitation. Winemakers can lower the likelihood of crystals forming by avoiding additives containing calcium, avoiding deacidification, considering acidification for high pH wines, creating a wine with a lower ethanol content, and avoiding malolactic fermentation
Investigating γ Doradus pulsating stars in spectroscopic binary systems.
Full text linkThis thesis presents the results of an orbital and asteroseismologic analysis of three γ Doradus
stars in spectroscopic binary systems. The three binary systems are HD 147787, HD 214291,
HD 10167 and they were observed using photometry and spectroscopy. Photometric data was
obtained from the Transiting Exoplanet Survey Satellite (TESS) and spectroscopic data was obtained
using the 1.0-m McLellan telescope with the High Efficiency and Resolution Canterbury
University Large Echelle Spectrograph (HERCULES) at the University of Canterbury Mt John
Observatory. A total of 7 sectors of data from TESS were analysed and over a thousand spectroscopic
observations from Mt John were reduced using the MEGARA pipeline. Cross-correlated
line profiles were obtained for each spectroscopic observation and were analysed.
The Specbin spectroscopic binary analysis software was used to conduct an orbital analysis of
all three systems. HD 147787 was determined to have an orbital period of 39.88 days, HD 214291
had an orbital period of 1.742 days, and HD 10167 had an orbital period of 9.319 days. Other
orbital parameters were calculated, and the artificial orbital fit data were used to remove the orbital
velocities from the components in each of the binary systems. Gaussian fits to the cross-correlated
line profile were used to model and remove the non-pulsating stars from the combined line profile.
Using the software packages FAMIAS and SigSpec for frequency analysis of photometric and
spectroscopic data, pulsation frequencies were identified for the pulsating component in each
binary system. HD 147787 had six identified pulsation frequencies, HD 214291 had three frequencies
for star 1 and two for star 2, while HD 10167 had three frequencies determined. All
measured frequencies were within the γ Doradus frequency range of 0.3 to 3 days⁻¹. From the
spectroscopic mode identification with the FAMIAS software, all identified pulsation modes are
low-degree modes (l ≤ 3). From the frequency analysis and mode identification, all stars were
confirmed to be γ Dor stars, with refined pulsational frequencies and improved orbital parameters
LLM meets LLM : AI revolution in New Zealand's legal profession - exploring junior lawyers' experiences, curriculum alignment, and cultural implications.
Full text linkThis study explores the impact of artificial intelligence (AI), particularly large language models (LLMs), on junior lawyers' work in New Zealand's legal profession. Existing research on AI in law primarily focuses on its technical capabilities, overlooking the lived experiences of legal professionals navigating this technological shift. To address this gap, this study employs a qualitative approach to investigate the essence of AI integration in legal practice and its psychological and practical effects on junior lawyers and their work. Ten semi-structured interviews were conducted with a diverse purposive sample of junior lawyers across New Zealand. Thematic analysis identified two major themes in junior lawyers' lived experience: Transforming Legal Practice and Opportunities and Challenges for Junior Lawyers, as well as an overarching theme of Te Tiriti o Waitangi (The Treaty of Waitangi), which is woven through all themes, sub-themes, and categories in this research. The findings focus on three key areas: the psychological and practical effects of AI on junior lawyers' work, the alignment between legal education and the emerging AI-driven profession, and the intersection of AI, law, and Māori customs, primarily Te Ao Māori (Māori worldview) and Tikanga (Māori customary law). Findings show that while AI can enhance productivity, it raises concerns about job security, ethical dilemmas, and the shifting of junior lawyers' roles from routine tasks to more complex, analytical, and interpersonal work. This study also identifies a significant disconnect between legal education and the realities of AI- integrated practice and uncovers the risks of AI perpetuating biases, particularly for Māori clients. This research contributes to understanding AI's impact on the legal profession in New Zealand, offering insights for legal educators, law firms, and policymakers. It emphasises the need for targeted training, ethical guidelines, and cultural sensitivity in AI implementation, paving the way for a more prepared and resilient legal workforce in the face of technological change
Prediction of road blockages caused by rainfall-induced landslides
Full text linkThis paper develops and evaluates an approach to predict road blockages caused by rainfall induced landslides, using an indicator for landslide triggering (landslide probability, rainfall)
and modelling landslide runout via the viewshed (area visible from the road). Based on the
landslide inventory of 2023 ex-tropical Cyclone Gabrielle, the study investigates the
prediction potential of this approach, focussing on the influence of different digital
elevation model (DEM) resolutions. Findings suggest that coarser DEMs (20 or 25 m) slightly
outperform finer resolutions (5 or 10 m), likely due to the other input variables presenting
similar resolutions. While the viewshed approach effectively identifies larger road blockages,
it fails to predict smaller blockages. Results also indicate a tendency to overestimate the
extent of blockages, which can be addressed by evaluating landslide hazards at a road link
scale (e.g. between intersections) rather than individual 100 m-segments. Uncertainties arise
from using precipitation as a triggering variable as the precise time of landslide initiation is
unknown, preventing the accurate calculation of the accumulated rainfall. Despite
limitations and the need for further research, the viewshed approach presents a valuable
tool for the prediction of road blockages during future rainfall events, providing critical
information for emergency planning and mitigation efforts
Landslide dam hazard and exposure modelling for an alpine fault earthquake.
Full text linkThe natural blockage of a river via landsliding is a common phenomenon in mountainous landscapes known as a landslide dam. Landslide dams can fail suddenly and catastrophically, releasing impounded water that can put downstream communities at risk of outburst flooding. The impoundment of water can inundate the area upstream and form a lake, which in some cases can remain in the landscape for millennia. Thus, there is a growing body of research focused on the processes involved in the formation and failure of landslide dams. However, there is a limited understanding of landslide dam hazard and exposure prior to their formation.
This thesis develops new methods for assessing pre-formation landslide dam hazard and exposure, applying these to a future earthquake scenario on the Alpine Fault in Aotearoa New Zealand. In the absence of empirical Alpine Fault landslide data, this study investigates the New Zealand Landslide Dam Database to inform critical modelling decisions. In doing so, this thesis develops a method framework that considers the likelihood and intensity of landslide dam formation to quantify the hazard posed by rivers. To determine whether future landslide dam formation may expose communities to outburst flooding, this study models a potential flood area for each catchment. Using both hazard and exposure, this research identifies catchments that pose high landslide dam threat, which is critical for improving Aotearoa New Zealand’s disaster resilience.
In an Mw 8.0 Alpine Fault earthquake scenario, this thesis finds that > 28,700 permanent residents are exposed to the 100 most threatening catchments. The highest threat catchment is the Callery River in Franz Josef, exposing ~570 permanent residents and potentially > 3,000 tourists to landslide dam hazard within the 99th percentile. Having similar landslide dam hazard to the Callery River, the Cleddau River in Milford Sound exposes ~80 permanent residents and potentially ~3,700 tourists. The Shotover River in Queenstown also poses high landslide dam threat as it exposes > 8,800 permanent residents to high landslide dam hazard. Another notable example is the Haupiri River, which exposes > 700 permanent residents including the Gloriavale Christian Community. The results of this thesis show that landslide dam hazard and threat in an Alpine Fault earthquake is concentrated in catchments west of the Southern Alps. For example, 58 of the 100 most threatening catchments are in the Westland District, with 28 of these exposing Franz Josef.
This research contributes to the wider body of landslide dam literature by developing methods for the assessment of landslide dam hazard and exposure before their formation. While these methods are applied to an earthquake scenario, the conceptual model is trigger-agnostic and can be altered for aseismic landslide dam modelling. Such modelling is critical for identifying locations where future landslide dam formation is likely as well as determining whether communities are exposed to potential outburst flooding. There is an opportunity for future research to focus on the catchments identified within this study. Furthermore, the identification of specific high-threat catchments can guide emergency planning and response for a future earthquake on the Alpine Fault
Social entrepreneurship in tourism: A framework-based scoping review and research agenda
Full text linkWhile tourism social entrepreneurship (TSE) has been gaining the interest of tourism scholars, little is known about the extent of knowledge on TSE and how understanding this phenomenon may be advanced. To address these gaps, we conducted a framework-based scoping review of academic publications (N = 190) on this topic published from 2006 to 2023. We operationalised Gartner's (1985) framework for new venture creation comprising four dimensions namely individuals, organisations, environment, and processes, which we have extended to include a fifth dimension on impacts to further reflect the societal value of TSE. We found that knowledge of TSE is centred on processes, indicating a strong focus on the supply side of this tourism development approach and signalling critical knowledge gaps especially on individuals and impacts of TSE. We propose a conceptual model that shows the complexity and multidimensionality of TSE. Finally, we contribute a research agenda to advance knowledge of TSE
OCHT properties regional transportation accessibility analysis :how to improve tenants’ transportation efficiency and living experience?
Full text linkTransport accessibility is a key factor in urban planning, influencing regional economic development, community cohesion and residents' well-being. While transport accessibility has been widely studied in the academic field and has a certain importance in promoting sustainable urban development and social equity, there is still a certain gap in its impact on social housing communities and residents with difficult transport choices. Christchurch is characterized by a strong car culture, with private cars as the main means of transportation. However, 25% of the population in the Canterbury region has a disability and nearly 90% of OCHT (Ōtautahi Community Housing Trust) tenants do not have the ability to travel by private car. Many residents face travel difficulties and lack effective transportation options.
This study adopted a mixed research methods approach, combining geographic information system (GIS) spatial analysis, QGIS web-based accessibility modelling, and secondary data analysis from OCHT and Christchurch City Council. Service area analysis and isochrone mapping were applied to quantify accessibility by different modes of transport, including walking, cycling, public transport, and driving. Meanwhile, accessibility to supermarkets, bus stops, clinics, parks, schools, and artworks near OCHT properties was assessed. In addition, demographic and housing data from OCHT provided context for interpreting accessibility constraints faced by tenants. The study aimed to: (1) assess the transport status of OCHT tenants, (2) analyse the accessibility of key amenities and transport infrastructure around OCHT properties, (3) identify strategies to enhance transport options and improve tenants’ living experience, and (4) inform future property allocation and development planning in OCHT. This study combined transport accessibility analysis with social housing research to develop accessibility profiles for each property, providing insights into potential differences in accessibility levels and infrastructure provision between different neighbourhoods and areas. And provides a quantitative basis for optimizing housing placement according to accessibility needs, ensuring improved living conditions for tenants, especially those with low incomes or limited mobility. By strengthening connections between OCHTs and their tenants, the research aims to support equal access to transport and infrastructure services, thereby promoting the development of more inclusive and resilient communities
Tracing the chemical evolution of globular clusters.
No full text1.1 Globular Clusters
Globular Clusters (GCs) are dense, old stellar clusters, often containing hundreds of thousands of
stars. They lie predominantly in the halo of the Milky Way (MW) but are also present in the bulge
and thick disk with often extreme internal kinematics and metal-poor stars (Gratton et al. 2019).
A robust definition of a GC is still being debated with many factors now taken into account such
as the cluster mass, metallicity and which region in the galaxy the cluster belongs to, as well as
investigations into chemical properties (Carretta et al. 2010). GCs were originally thought to be
simple stellar populations, that is, they are comprised of stars with similar ages and abundances
(Bastian and Lardo 2018). However, more complex chemical trends have been observed with large
intra-cluster variations for many elements, indicating GCs can have multiple stellar populations
(MSP).
A prominent chemical feature of most GCs are the presence of anti-correlations. In particular,
the sodium-oxygen (Na-O) and magnesium-aluminium (Mg-Al) anti-correlations (Gratton et al.
2001; Carretta et al. 2009b; Pancino et al. 2017b; Bastian and Lardo 2018). Na and O undergo
more internal mixing in stars compared to Mg and Al, therefore, Mg and Al abundances have
minimal dependance on a star’s evolutionary stage (Pancino et al. 2017b). This allows the Mg-Al
anti-correlation to act as a tool for tracing the chemical enrichment history of GCs. The observed Mg
and Al abundances reflect the contributions of previous generations of stars, unaffected by ongoing
nucleosynthesis in the observed stars. However, clusters that do exhibit Na-O anti-correlations
do not always show Mg-Al anti-correlations as well, therefore the Na-O anti-correlation can be
utilised in more clusters to determine the existence of multiple populations (Bastian and Lardo 2018).
There are two main theories of where GCs form, either they are part of their host galaxy’s initial
formation, or they have formed externally to then be accreted into another galaxy (Gratton et al.
2019). External accretion has been supported by studying stellar morphology within clusters, and
by counting the number of GCs in nearby dwarf galaxies, the Milky Way is proposed to have had
approximately seven merger events with cluster-bearing dwarf galaxies (Mackey and Gilmore 2004).
This would generate the roughly 41 external clusters as determined from Mackey and Gilmore
2004. A slightly wider range of 27-47 possible external clusters from 6-8 dwarf galaxies was found
in Forbes and Bridges 2010. Today, the Milky Way is known to contain at least 151 GCs with the
origin of some still uncertain (Massari et al. 2019).
Spectroscopy is the study of starlight, often in optical or infrared wavelengths, to determine
characteristics of stars such as their astrophysical parameters and chemical abundances. As GCs
have a tight distribution of stars in the centre, it can be challenging to observe resolved stars in this
region. Integrated light observations allow the study of stars within the cluster centre where multiple
stars are observed at once in a single spectrum. However, individual stellar spectra can be obtained
for stars that lie outside of this dense region. Spectroscopic observations of GCs can be undertaken
by either obtaining integrated light spectra, or single stellar spectra where individual cluster members
are observed. The chemical information obtained from examining spectra of GCs contains crucial
information about the abundance of specific elements in the atmosphere of the stars. By observing
many individual cluster stars, detailed intra-cluster variations can be explored to determine possible
multiple populations and their origins.
1.2 Research Motivation
The primary aim of this thesis is to investigate chemical trends within globular clusters (GCs) using
the Gaia-ESO Survey (GES) (Gilmore et al. 2012; Gilmore et al. 2022; Randich et al. 2022) GC
sample. Part of this is to assess if additional abundances can be determined to expand the sample.
The GES GIRAFFE medium resolution and UVES high resolution spectra will be reassessed to
determine if any additional chemical abundances can be measured using iSpec (Blanco-Cuaresma
et al. 2014; Blanco-Cuaresma 2019). iSpec is a python wrapper around spectral synthesis codes
and in this thesis, will be utilised with the synthesis code MOOG (Sneden et al. 2012). This method
results in a synthetic spectrum created to be compared with the observed using a least squares fit.
This fit is then minimised, producing the determined chemical abundances for the corresponding star.
The analysis of these abundances will focus on the intra and inter-cluster chemical trends,
investigating both individual clusters and the entire GC population. Specifically, the trends for
elements that strongly represent an astrophysical process such as a nucleosynthesis and enrichment
processes. These elements are also known as tracer elements and are crucial for understanding
the underlying contributions to stellar formation within GCs. Using tracer elements can help to
determine the existence of any multiple populations and generations of stars with GCs, and their
typical chemical trends. A comparison to the wider Milky Way chemical evolution will also be
performed to provide insight into how these clusters relate to the MW as a whole, as well as the
detection of possible accreted clusters from other galaxies. The presence of any accreted clusters
provides opportunity to examine extra-galactic GC abundance trends and implications. These
abundance analyses will contribute to understanding the elusive characteristics of GCs.
The secondary aim of this work is to investigate the capabilities of the University of Canterbury
Ōtehīwai Mt John Observatory for GC analysis. This capability of the University of Canterbury
Ōtehīwai Mt John Observatory will be tested by obtaining integrated light spectroscopy on the
1-metre McLellan telescope and the High Efficiency and Resolution Canterbury University Large
Echelle Spectrograph (HERCULES). As with the GES spectra, iSpec will be used except this time,
for the determination of astrophysical parameters such as metallicity and radial velocity. A comparison
between the literature values of GCs observed and the derived parameters will be used to
assess the quality of GC studies at Ōtehīwai Mt John Observatory. As the current observations on
the 1-metre McLellan telescope are exclusively bright (V< 9), resolved targets, pushing the limit to
fainter targets would provide new research opportunities and future programs.
1.3 Thesis Structure
This thesis has the following structure. Chapter 2 discusses the background and theory of topics
used in the thesis such as the chemical properties of stars and their application on the wider chemical
evolution of the Milky Way galaxy. Chapter 3 outlines the methods, results and brief discussion of
integrated light spectroscopy for two GCs obtained at the University of Canterbury’s Ōtehīwai Mt
John Observatory. In Chapter 4, the spectral synthesis method for obtaining additional abundances
from the Gaia-ESO Survey spectra is described. The abundance results from this are shown in Chapter
5 for the eleven elements investigated in this project and across the fourteen Globular Clusters.
The analysis of the chemical trends and multiple populations from the determined abundances is in
Chapter 6. Chapter 7 discusses the findings and wider implications of this project to the chemical
understanding of the Milky Way. Finally, Chapter 8 concludes the work done in this thesis and
provides an overview of any possible future work
Student reflections on the transition from primary to intermediate school: exploring expectations, coping and Kiwi Can participation.
Full text linkThe transition from primary to intermediate school represents a significant period of change and opportunity for early adolescents, who must adjust to an unfamiliar environment while also navigating a critical developmental milestone: the onset of puberty. Many students face social, academic, and emotional challenges that can impact their overall wellbeing. Despite its significance, research has predominantly focused on other school transitions, leaving a gap in understanding students’ lived experiences. Informed by the Transactional Model of Stress and Coping and Resilience Theory, this qualitative research explored students’ reflections on their transition, focusing on their expectations, adjustment, and coping. It also examined students' perspectives on the Graeme Dingle Foundation’s Kiwi Can program and its application to their primary-intermediate school transition. Ten year-seven students participated in semi-structured interviews, and students’ primary caregivers completed a questionnaire with similar open-response questions as the student interviews for a supplementary data source. The findings revealed that students primarily held negative expectations about intermediate school, often shaped by external sources. Social concerns were particularly salient; however, the extent of peer conflict and complex social dynamics was unexpected. Although academic difficulty increased, the changes were often overestimated. A positive aspect of the transition to intermediate school was the opportunity to participate in extracurricular activities and novel subjects, fostering self-expression. Students were proficient at identifying their coping strategies, particularly relying on peer support and self-directed emotional regulation. Some students attributed their application of resilience and social-emotional skills to Kiwi Can, while others did not consciously make direct links. Findings on expectations, lived experience, and coping aligned with literature on intermediate transitions, offering rich qualitative insights to inform practices and policies that promote a smooth transition
State-of-the-Art Review: Electronic Warfare against Radar Systems
Full text linkThe electromagnetic spectrum (EMS) is emerging as a sixth battlespace domain in military
applications and is essential for wireless communications and remote sensing. Due to the demand for EMS,
it is increasingly contested, congested, constrained, and shared. Evolving threats, doctrine, and tactics drive
significant advancements in the battlespace. Electronic Warfare (EW) or Electromagnetic Warfare products
need to keep pace by leveraging advances in technology driven by Industry 4.0, artificial intelligence (AI),
direct radio frequency (RF) sampling, RF System on Chip (RFSoC), and ultrawideband antenna arrays. These
trends drive a need for technology-intensive innovation in EW products underpinned by a coherent business
product-technology strategy. This article reviews advancements in Electronic Warfare against radar systems
using a novel approach that integrates quantitative bibliometric and patentometric analyses with a qualitative
assessment of EW architectures, Electronic Attack (EA) algorithms, and Electronic Support (ES) algorithms.
This article marks the first instance of such a methodology being applied to systematically assess the
landscape of research publications and technological innovations in the field of EW against radar systems. A
taxonomy of EW System Types by military domain against radar and their role in the modern battlefield is
presented together with their typical role and real-world examples. The quantitative and qualitative insights
are synthesized to outline a notional next-generation EW architecture and a technology roadmap for its
realization that researchers can use to guide the development of innovative EW technologies and
methodologies and by EW practitioners to inform system design, operational deployment, and capability
enhancements