Open Access Theses

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Access status: Open Access ,
Johann Gottlieb Graun : three symphonies : a performing edition with critical commentary
(1983-11) Platt, Heather.
The purpose of this annotated edition of the Symphonies M9 in C, M34 in D and M100 in F is to make three more of Johann Gottlieb Graun’s works readily accessible to musicologists and performers, and in doing so to make a small contribution to the research currently being undertaken into the pre-Classical symphony. A biography of Graun and a discussion concerning his symphonic style are included so that these works may be viewed in their historical perspective. Graun studied violin with Pisendel and Tartini and was himself ranked among Europe’s leading violinists. He was Frederick the Great’s concertmaster for at least thirty-six years, during which time he was responsible for the discipline of the highly acclaimed Berlin opera orchestra. Graun’s compositional output is dominated by instrumental genres, including at least ninety symphonies. These Italianate symphonies are clearly transitional in style, the structure of the outer movements owing more to the rounded binary movements of the Baroque dance suite than to Classical sonata form, while the phraseology of the subjects and the slower harmonic rate of these same movements look toward the future. The slow movements vary in size from mere transitional passages to full-scale binary or ternary movements. However, all too often the melodic lines are disrupted by complex subdivisions of the beat, sudden dynamic contrasts and rests. Despite the uneven quality of his symphonies, Johann Gottlieb Graun holds an important historical position for two reasons. Firstly, he made a major contribution to the dissemination of the Italian symphony throughout northern Germany in the 1730’s and 17AO’s, and, secondly, he was among the first of the north German composers to write mainly concert symphonies.
Access status: Open Access ,
The professional orchestra in the United States : current problems and solutions for improving its future
(1994-12) Balej, Janet Elizabeth.
Professional orchestras have existed in the United States for over a century and a half and enjoyed especially great popularity in this century.
Access status: Open Access ,
Chopin as composer and pianist : stylistic sources
(1994-11) Crisp, Deborah.
Although he was, and is, regarded as one of the foremost virtuosos of the romantic tradition, Chopin considered himself to be apart from that tradition. In his own time, reviews and other reports of his playing and compositions never fail to mention the uniqueness of his style as pianist and composer. However popular he remains, almost 150 years after his death, it is difficult, if not impossible to grasp the extent of his uniqueness, and its precise nature. This thesis sets out to identify significant influences upon the formation of Chopin's style as pianist and composer, and to demonstrate ways in which these are manifested in his work: The writer seeks to confirm Chopin's own assessment of his position as being set apart from the mainstream tradition in his composition, his teaching, and his playing. First, details of Chopin's musical education are examined: in particular the fact that it was primarily directed towards a career in opera composition. The significance of this education is demonstrated in several aspects of his subsequent career as a pianist composer. First and foremost, the very fact that he was not trained (in the usual sense) as a pianist - that he was never subjected to the repetition of conventional pianistic formulae in the form of scales and exercices - must account to some extent for the very different patterns and textures that he was able to discover on the keyboard. The training he did receive appears to have been very rigorous, and perhaps somewhat conservative. Evident in the compositions is a firm grasp of the principles of counterpoint - a feature of his early training with Eisner. His high regard for the work of J.S. Bach is also apparent in the compositions, and it is suggested that Chopin in many ways adopted an eighteenth century attitude towards the composition of particular genres. This reliance on an older tradition is demonstrated also in Chopin's career as pianist and teacher, both in specific technical details and in his attitudes towards performance. The influence of opera is readily apparent in Chopin's compositions, and in accounts of his playing and teaching. This thesis suggests that this influence is more far-reaching: that Chopin's style as pianist and composer is essentially vocal in its conception, and that this was in marked contrast to other composers of the time, whose aim was to emulate the larger palette of the orchestra. The distinctiveness of Chopin's style has often been attributed largely to his Polish origins. This influence is also examined here, though in less detail. It is the writer's contention that this influence has, in general, overshadowed appreciation of the extent to which Chopin's style is based upon eighteenth century techniques and attitudes.
Access status: Open Access ,
"That prelude" : a study of the rise & fall in popularity of Rachmaninov's Prelude in C sharp minor
(1994-11) Bear, Louise.
In 1892, while still studying at the conservatorium in Moscow, Sergei Rachmaninov composed a short prelude in C sharp minor which was to become a focal point for his future career as a performer and composer.
Access status: Open Access ,
The Rückert Lieder of Schumann : an analysis of the musical language
(1990-03) Huddleston, Kylie.
The Lied is a unique artistic form, in that it has as its basis a previously existing work, complete in itself.
Access status: Open Access ,
Vocal intonation : an exposition of Pál Kardos' pedagogy of acoustically pure intonation for a cappella music
(1995-02) Pickering, Judith Christine.
Good intonation is an essential condition of a cappella choral music, yet a systematic understanding of how to achieve it is rare among choral directors and aural trainers.
Access status: Open Access ,
Self-esteem and how it relates to singing teaching : an annotated bibliography
(1999-12) Klemke, Michelle
This research project is comprised of an annotated bibliography on self-esteem and how it relates to singing teaching. It is written as the research requirement of the Graduate Diploma of Music (Pedagogy) in the Canberra School of Music, Institute of the Arts, Australian National University. The aims of this project are: • find and review research on this topic • identify the most relevant literature • analyse the literature on how self-esteem interacts with singing • analyse the literature on the relationship between the technical and nontechnical aspects of singing • suggest future research in this area The research undertaken suggests that there is much evidence to support the premise that a relationship exists between singing and self-esteem. The literature suggests that a singing teaching method which involves maintaining a student’s positive self esteem greatly enhances that student's achievement in both technical and non-technical areas of singing and helps them reach their full musical potential. The annotated bibliography is divided into four sections: singing and singing teaching (adults); singing, music and singing teaching (children); music and psychology; and self-esteem. The project highlights a need for further research in this area and an Appendix contains material that may be useful in this regard. This material was unavailable for inclusion in this project.
Access status: Open Access ,
Australia's national song : a catalogue and a chronology
(1981-05) Elias, Anthony.
Australia has taken one hundred and fifty years to acquire a national anthem/song which enjoys even the official recognition which has been accorded Advance Australia Fair. The Australian people have not been unanimous in their choice of the 'most fitting' national anthem for Australia. Attention is drawn to a general ignorance of the nature, and manner of choosing, a national anthem. The histories of various national anthems are traced, showing how they achieved their status. The history of Australia's attempt to find for itself a national anthem is then followed, suggestions being offered as to why most of the various official efforts have failed. There is also a table of contents, a list of plates, a thematic catalogue, an acknowledgements page, a bibliography and an index.
Access status: Open Access ,
Magnetic force microscopy of thin magnetic films
(1993-03) Barnes, Jack Richard.
The development of the Scanning Tunnelling Microscope (STM) in 1982 by Binnig and Rohrer [1] provided the technological leap that spawned several other types of Scanning Probe Microscopes (SPMs), such as the Atomic Force Microscope (AFM) [2] and Scanning Near Field Optical Microscope (SNOM) [3].
Access status: Open Access ,
Using Machine Learning Methods to Estimate Maternal Mortality Ratios
(2025) Rosenberg, Rosalita
Maternal mortality is an ongoing, critical international health challenge, especially in low- and middle-income countries. In 2023, the global maternal mortality ratio (MMR), or the number of maternal deaths per 100,000 live births, was 197. Approximately 95% of maternal deaths occur in low and lower-middle income countries and fragile settings. Many of these deaths could have been prevented by using existing, effective interventions. The World Health Organisation has highlighted how low-quality, sparse data about maternal mortality hinders effective intervention, especially as countries with the highest MMRs tend to have the most missing data. The primary contribution of my thesis to the literature was its development of decision-tree based machine learning models to predict the MMRs of 172 countries between 1985 and 2018 using data from the World Health Organisation and World Bank. In contrast to existing approaches, my proposed models estimated MMR without needing to make explicit assumptions about the underlying distribution of data. My models also used a wider range of socio-economic and health-related features than existing methods. This produced an alternative set of MMR estimates that can be used provide consensus about the true MMR values as well as encourage debate about the validity of different MMR modelling techniques. The best-performing Random Forest Stacking Ensemble achieved a test mean relative error of 0.07 when predicting all MMR data for a specific country and a test mean relative error of 0.37 when forecasting MMR values. Despite being limited by low-quality and sparse input data, my models’ MMR predictions were similar to those produced by the most widely used models in the literature, reinforcing their validity. The socioeconomic and health-related variables with highest predictive power for MMR in my models were established risk factors. My analysis highlighted the importance targeting socio-economic drivers of maternal mortality, such as women’s employment prospects, to successfully reduce maternal deaths.
Access status: Open Access ,
Acoustic communication and collective decision-making in social animal groups
(2026) Liao, Chun-Chieh
Many species live in complex societies in which individuals must coordinate their behaviour to maintain cohesion and gain the benefits of social living, both within and between species. Communication plays a central role in enabling rapid coordination and reducing consensus costs when group members differ in their needs and information. In this PhD thesis, I examine how social animals use communication to coordinate behaviour, particularly in antipredator contexts. The thesis includes introductory and concluding chapters (Chapters 1 and 7), a conceptual review (Chapter 2), and four empirical studies on social birds (Chapters 3-6). In Chapter 2, I develop a conceptual framework describing how acoustic signals and movement cues are used to coordinate behaviour in social animal groups. By integrating information masking, discrimination ability, and encoding limitations, the framework predicts that behaviours involving the timing of events or the expression of specific actions should rely more on acoustic signals, whereas decisions involving complex choices should generally rely on movement cues. This framework also highlights key future directions, including multimodal communication and decision-making in mixed-species groups. Guided by this framework, I conducted three playback experiments on white-winged choughs (Corcorax melanorhamphos), a highly social cooperative breeder. In Chapter 3, I show that adult choughs possess a functionally referential alarm-call system that conveys threat type and urgency. Choughs produce three distinct alarm calls: terrestrial alarms for ground-based predators, aerial whistles for high-flying hawks, and flee alarms for high-urgency threats. Birds responded appropriately to alarm-call playbacks, typically looking around to terrestrial alarms, looking upwards to aerial whistles, and fleeing to flee alarms. In Chapter 4, I show that young choughs develop appropriate alarm-call responses slowly, remaining poor at interpreting alarm calls for several months after fledging. Most juveniles responded to all alarm types by simply looking around, even when exposed to high-urgency flee alarms, suggesting that extended social protection and vocal complexity may shape learning in this species. In Chapter 5, I show that choughs integrate multiple components of social alarm information to coordinate collective antipredator behaviour. They assess alarm-call type to decide what action to take, and caller number to modulate both the intensity of their response and the likelihood of propagating alarm information to others. This decision rule helps reduce false alarms and unnecessary information cascades that can negatively affect group living. Together, these findings demonstrate how acoustic communication enables white-winged choughs to remain both safe and cohesive. In Chapter 6, I extend these insights beyond single-species societies to mixed-species systems. I conducted playback experiments to examine danger information transfer in mixed-species bird flocks in Taiwan. I find strong asymmetries in predator detection and/or danger communication between leader and follower species, with leader species always initiating mobbing calls. However, mobbing calls from leaders did not elicit stronger antipredator responses than those from followers. I propose that larger conspecific group sizes and kin-selected behaviours may favour the evolution of superior antipredator signalling in leader species, leading to asymmetric information transfer about danger between species. These results further suggest that mutual antipredator benefits are common in mixed flocks, promoting positive interspecific interactions and enhancing flock cohesion. Together, these findings suggest that sociality not only increases animals' reliance on social information, but also favours communication systems that allow information about danger to be encoded, assessed, and shared in ways that support effective antipredator behaviour.
Access status: Open Access ,
Studying blood-based immune biomarkers for cancer and their confounders
(2026) Florencia, Lulu
Background: Cancer is a leading cause of death worldwide, with survival strongly dependent on stage at diagnosis. Current screening approaches for early-stage cancer are largely designed to detect a single cancer type, can be invasive, and often have limited sensitivity and specificity. Blood-based immune biomarkers offer a promising, minimally invasive approach for multi-cancer detection, as tumour development induces measurable systemic alterations in circulating leukocyte composition. However, immune profiles are inherently variable and influenced by biological and environmental factors independent of disease status, including genetic background, sex, age, diet, and exercise. The impact of these confounders on immune-based cancer detection is poorly characterised, representing a gap between preclinical findings and clinical translation. Hypotheses/Aims: The central premise of this study is that circulating leukocyte profiles differ between healthy and cancer-bearing individuals, but that intrinsic and extrinsic variables influence these profiles and reduce their ability to indicate cancer if not appropriately accounted for. We further hypothesise that predictive models matched to the host background detect cancer more reliably than mismatched models. The aims were therefore to evaluate the utility of blood-based immune profiles for multi-cancer detection, to assess how biological variability influences classification performance, and to determine whether matching the model to the host background improves detection. Methods: Three syngeneic murine tumour models were used: CT26 (colorectal), 4T1 (mammary) in female BALB/c mice, and RM1 (prostate) in male C57BL/6 mice. Blood was collected at early and late tumour stages, and immune cells were characterised using high-dimensional spectral flow cytometry. Multivariate analyses (PERMANOVA and PCoA) assessed group differences, and Random Forest classification evaluated cancer detection performance, with SHAP-based feature importance identifying key immune predictors. Biological variability was assessed by comparing immune profiles across healthy populations differing by genetic background, sex, age, exercise, diet, and housing environment, and across tumour-bearing populations varying by age and sex within a consistent BALB/c background. Results: First, late-stage tumours produced distinct, tumour-specific immune signatures reliably detectable from blood, whereas early-stage cancers closely resembled healthy controls, with substantial overlap limiting sensitivity. Second, intrinsic factors, particularly genetic background, produced immune variation exceeding tumour-associated changes in many comparisons. Models trained on mismatched healthy populations showed significantly reduced accuracy, primarily impairing early-stage detection while late-stage disease remained detectable; this was not resolved by increasing training data alone, indicating that biological matching, not sample size, is the primary determinant of performance. Third, classification performance was strongly background-dependent in tumour-bearing populations, with old female BALB/c mice achieving the strongest early-stage detection (92% accuracy, 88% sensitivity), while old male BALB/c mice showed consistently reduced performance. Conclusion: Blood-based immune profiles can detect cancer under biologically matched conditions, but reliability is substantially reduced by biological variability, particularly for early-stage disease. This study establishes a preclinical framework for how biological heterogeneity shapes immune biomarker performance and highlights that reliable multi-cancer detection requires a framework accounting for the biological context of both healthy and tumour-bearing populations. These findings inform the future development and clinical translation of blood-based immune biomarkers for cancer screening.
Access status: Open Access ,
The contribution of contemporary Australian composers to the tenor concert repertoire
(1998-06) Cooper, Carl Gerard.
This sub-thesis presents information on composers, selected works, and the views of well known artists who perform new Australian works for the tenor concert repertoire. The sub-thesis is divided into five chapters. The introduction forms Chapter One. Chapter Two discusses Australian composers and their attitudes to their compositions, including their reasons for composing for the tenor voice in particular. Chapter Three evaluates one of the tenor pieces of each of the four Australian composers selected for study. This evaluation discusses the performance requirements of their pieces, and the technical requirements and specific difficulties of the tenor voice. Chapter Four discusses prominent Australian tenor artists' music education, their experiences in dealing with this repertoire, their relationship with Australian composers, and their future interests in this area. Chapter Five concludes the study and provides a closer examination of the current and future directions of concert works for tenor written by contemporary Australian composers. This sub-thesis attempts to give a considered opinion on the paucity of Australian repertoire available to tenor artists for performance andoffers reasons concerning why this situation has developed. The study concludes that the relationship between composer and performer has been responsible for the collaborative nature of some compositions and their performance. On closer observation, the lack of continued performance of these new works is a cause for concern for Australian composers who have written for the tenor concert repertoire, as well as tenor artists who have performed these compositions.
Access status: Open Access ,
Re-discovery of traditional music in Choong-shin Presbyterian Church, Korea
(2001-06) Kim, Jung-min.
This thesis is a study of Korean church music. It investigates the place and nature of music in the Korean Christian church for seeking links between Christianity and Korean traditional music, and trying to define the Korean church’s musical identity. The introduction of Christianity brought radical changes to Korean culture and society. Music was one of these sweeping changes. Although church music has been debated in relation to seeking Korean musical identity, however, Western music has dominated the use of music in church. This phenomenon continues in the contemporary Korean church. However, changes in this situation are beginning to be evident, as some Korean composers consciously apply aspects of traditional music in their works. In spite of this, the use of traditional music in church has not yet been viewed positively because of the Korean church’s indifference and conservatism. However, church music cannot ignore and suppress musical concepts that separate the people in the congregations from their cultural characteristics and the forces of change in the society. A new conception of music for the Korean church is raised here as an important subject, to be considered with the changing musical identity. This study provides a conceptual foundation upon which the Korean church can build and develop its church music into the future.
Access status: Open Access ,
Artificial Intelligence and Organisational Viability in Early Stage Venture Capital
(2026) Jasper, Michelle
Early-stage venture capital (ESVC) decision-making operates under conditions of persistent uncertainty, partial visibility of work, and long feedback delays between investment decisions and outcomes. While recent attention has focused on the potential of artificial intelligence (AI) to improve investment decision-making, less attention has been given to how AI interacts with the organisational structures through which ESVC decisions are produced and regulated. This thesis addresses that gap by examining ESVC decision-making as a question of organisational viability rather than one of optimisation or individual judgement quality. Its aim is to diagnose how ESVC decision systems are functionally structured, how persistent structural tensions within those systems are managed across historical and contemporary practice, and what these tensions imply when AI alters the informational environment in which organisational regulation occurs. Drawing on organisational cybernetics, and in particular Beer's Viable System Model (VSM), this research adopts a diagnostic, abductive approach to analyse how ESVC decision systems manage complexity over time. The empirical study focuses on a single, bounded regional innovation ecosystem characterised by proximity to research institutions, deep-technology ventures, and dense relational networks among investors, intermediaries, and public agencies. Three analytical lenses structure the empirical work. The first examines a historical baseline through analysis of an anonymised ESVC archival corpus spanning eighteen years. The second examines contemporary practice through semi-structured interviews with ESVC practitioners, ecosystem orchestrators, and technology specialists. The third synthesises these lenses to identify persistent structural tensions and interpret their implications under altered informational conditions, specifically, the introduction of AI. The archival diagnosis shows that all core VSM subsystems were present but unevenly enacted, giving rise to structural tensions across four dimensions: autonomy and representability in operational work, formality and informality in coordination, authority and access in oversight, and discretion and consistency in normative governance. Practitioner accounts confirm that these tensions persist in contemporary practice despite changes in tools and organisational contexts, and that they are managed through informal judgement, trust-based calibration, and situational coordination rather than formal regulatory capacity. AI does not resolve these tensions but reconfigures the informational conditions under which they are managed, through four system-level effects: attenuation of local effort, amplification of interpretive misalignment, redistribution of regulatory pressure across roles and recursive levels and obscuring of tacit conditions under which decisions are produced and legitimised. This diagnostic reframes the regulatory function of features (trust, heuristics and informal judgement) that are commonly framed in the decision-making literature as sources of decision error. This thesis makes several contributions: it reframes ESVC decision-making as a question of organisational viability, positioning judgement, trust, heuristics, and bias as functional responses to structural conditions; it provides the first VSM diagnostic of ESVC decision-making at fund level, combining longitudinal archival and contemporary practitioner data; and it conceptualises AI as a redistributor of informational strain rather than a decision-maker or corrective, contributing a diagnostic lens for analysing how AI alters the conditions under which coordination, oversight and organisational learning occur in complex decision systems characterised by uncertainty and delayed feedback.
Access status: Open Access ,
Engineering Guided Polaritons and Nonlinear Light-Matter Interactions for On-Chip Photonic and Optoelectronic Devices
(2026) Suriyage, Manuka
Controlling light at the nanoscale underpins the advancement of next-generation photonic and optoelectronic technologies, particularly for on-chip integration, optical communication, and quantum information processing. However, conventional photonic systems are fundamentally limited by diffraction, weak light-matter interactions, and inefficient nonlinear effects at subwavelength scales. Overcoming these challenges requires platforms that enable strong coupling between electromagnetic fields and material excitations. In this context, polaritonic excitations and nonlinear optical processes provide complementary approaches for confining, guiding, and generating light within compact systems. Polaritons, arising from the strong coupling between photons and material excitations such as phonons and excitons, enable electromagnetic fields to be confined and guided well below the diffraction limit, supporting directional energy transport. Nonlinear optical processes enable functions such as frequency conversion and quantum light generation. However, challenges remain in achieving deterministic control over excitation pathways, maintaining long-range and low-loss propagation, and translating these effects into practical photonic architectures. Low-dimensional and anisotropic materials provide a promising route to overcome these limitations. Anisotropic polar dielectric crystals can support hyperbolic dispersion, enabling directional polariton propagation. Van der Waals materials offer strong optical confinement and tunable light-matter interactions, with TMDCs standing out due to their strong excitonic resonances and symmetry-dependent optical behaviour. The first part of the thesis focuses on the linear regime and the control of polariton propagation. In anisotropic materials, hyperbolic polaritons enable highly directional transport while remaining confined below the diffraction limit. A key example is the ghost hyperbolic phonon polariton (g-HP), which propagates with oblique wavefronts and exhibits long-range, ray-like behaviour. To address the challenge of selective excitation, a mode-selective approach based on structural asymmetry is developed, where micro- and nano-antennas act as momentum-selective sources. This enables directional propagation and extended propagation lengths. This approach is extended to atomically thin materials, where exciton polaritons emerge in TMDC monolayers. Despite strong excitonic responses, guiding light in such ultrathin systems is challenging due to weak confinement and environmental sensitivity. These limitations are addressed using a suspended monolayer design, enabling direct observation of guided exciton polaritons. The thesis further introduces an interaction-driven approach to topological polaritons. In contrast to conventional systems with pre-designed topology, the platforms studied here are initially topologically trivial. Non-trivial topological phases emerge from strong light-matter coupling, resulting in band hybridization and inversion, and giving rise to robust, backscattering-immune modes. These phases can be dynamically tuned through external parameters such as strain or electrostatic gating. The second part of the thesis focuses on nonlinear light-matter interactions. A valley-selective nonlinear meta-waveguide platform based on non-centrosymmetric TMDCs is developed, enabling efficient SHG with polarization selectivity and directional coupling into guided modes. Building on this, a metasurface-integrated waveguide platform is developed for quantum photonics, enabling efficient nonlinear interactions within a compact footprint. A counterpropagating excitation scheme enables phase matching, supporting both SHG and SPDC. Overall, this thesis establishes strategies for controlling light-matter interactions across both linear and nonlinear regimes, connecting fundamental studies with the development of practical photonic and optoelectronic systems.
Access status: Open Access ,
Papal thought on the nature of sacred music
(1998-01) Hope, Alison.
A member of any modern Catholic congregation, turning up two minutes after Mass had begun, would not be surprised to hear seeping out from the church the strains of congregational hymns, a solo singer on a microphone, or a folk mass, replete with drums and electric guitar.
Access status: Open Access ,
Optical Coupling of Semiconductor Nanowires
(2026) Jäger, Lukas
The continued growth of computational demand has shifted performance and energy-efficiency bottlenecks from individual processing units toward data movement within and between computing systems, where electronic interconnects are increasingly limited by energy consumption and bandwidth. Photonic integrated circuits offer a promising route to alleviate these limitations by enabling high-bandwidth, low-energy optical interconnects. As photonic systems are pushed toward higher integration densities, optical functionality must be realized within increasingly confined volumes, giving rise to strong interactions between neighboring photonic elements. Semiconductor nanowires, which combine subwavelength optical confinement with micrometer-scale propagation lengths, have emerged as versatile building blocks for nanoscale photonic systems, including active elements such as nanowire lasers. In densely integrated architectures, optical coupling between nanowires becomes unavoidable and can fundamentally modify device behavior, necessitating a detailed understanding of how such interactions influence nanoscale light sources. In this thesis, optical coupling between semiconductor nanowires is investigated experimentally and numerically, with a particular focus on the lasing regime. A bottom-up experimental approach is employed, in which deliberately designed nanowire assemblies with well-defined geometries are used to isolate coupling effects. This strategy enables systematic investigations of coupling in configurations ranging from individual nanowires to nanowire pairs and small clusters. Two complementary material platforms are studied: zinc oxide nanowires arranged laterally on a substrate and indium phosphide nanowires grown vertically with lithographically defined positioning. Optical coupling is examined through experimentally accessible observables, including emission spectra, far-field radiation patterns, and energy transfer between neighboring nanowires under optical excitation. By systematically varying nanowire geometry and local excitation conditions, this approach enables coupling effects to be identified and compared across the two complementary material platforms and nanowire configurations investigated in this thesis. Numerical simulations based on eigenmode analysis and finite-difference time-domain methods are used alongside the experiments to interpret the observed behavior and to assess the role of geometry, symmetry, and fabrication tolerances. In zinc oxide nanowire pairs, coupling leads to full and partial frequency locking, master–slave behavior, and controlled transitions between coupled and decoupled lasing states. Selective local excitation density is shown to provide an effective control parameter for selecting the collective state, and in one specific geometry enables single-mode lasing through coupling-induced mode suppression. In indium phosphide nanowire systems, deliberately designed vertical nanowire pairs support coupled supermodes with strongly modified far-field emission, resulting in pronounced directionality that is well reproduced by numerical simulations. The experimental observation of multiple supermodes, together with extended structures such as nanowire triplets and arrays, demonstrates that coupled nanowire geometries can be realized reproducibly using selective-area epitaxy within realistic fabrication tolerances. Taken together, these findings establish optical coupling as a powerful design tool for engineering collective emission and directionality in nanoscale laser systems, and identify semiconductor nanowires as versatile building blocks for active directional photonic structures and nanoscale metasurfaces.
Access status: Open Access ,
Synthetic and Computational Investigations of Highly Reduced Main Group Organometallics of Groups XIII and XIV
(2026) Nelmes, Gareth
This thesis concerns the fundamental understanding of low-valent compounds of Groups 13 and 14 through a combination of synthetic and computational investigations. Low-valent main-group species continue to challenge conventional descriptions of chemical bonding and reactivity, displaying unusual electronic structures and reaction pathways. Despite advances in the field, many fundamental questions concerning the stabilisation, electronic structure, and particularly mechanisms of formation and reactivity of these compounds remain unresolved. The work presented herein seeks to address several such questions through the synthesis of novel compounds, detailed electronic structure analyses, and extensive mechanistic investigations using density functional theory. Chapter 1 provides an introduction to low-valent main group chemistry and the computational methods employed throughout this thesis. Particular emphasis is placed upon the concepts of valency, electronic and steric stabilisation, density functional theory, and the interpretation of potential energy surfaces relevant to reaction mechanism elucidation. Chapter 2 presents two acridanide ligands, together with their alkali-metal salts and germanium(II) and tin(II) precursor complexes, were synthesised and characterised. Reduction chemistry involving simple alkali-metal reductants and a magnesium(I) dimer produced a variety of unusual products, including the first dimagnesiogermane. DFT was subsequently employed to investigate the electronic structure and mechanism of formation of this species, revealing a reductive-addition process across an Mg-Mg bond and providing insight into the formation of low-valent Group 14 compounds. Chapter 3 concerns the formation of a hexahydridosilicate dianion and its conversion into the parent silylene dianion. Benchmarking against experimental structural and spectroscopic data allowed the development of density functional methodologies for low-valent chemistry. Electronic structure calculations and kinetic modelling were then used to examine this transformation wherein the hexahydridosilicate loses two equivalents of dihydrogen to form the SiH2 dianion trapped within the molecular assembly. DFT revealed a reaction pathway consistent with experiment and an unexpected autocatalytic process as the origin of the observed reactivity. Chapter 4 investigates oxygen-extrusion reactions observed during attempts to prepare low-valent boron compounds. Exploration of the potential energy surfaces using DFT showed that closed-shell pathways were inaccessible, whereas open-shell pathways involving boryl radicals were consistent with both computational predictions and experimental observations. The resulting mechanism provides an explanation for an unusual reductive skeletal-editing process involving oxygen deletion and ring contraction. Chapter 5 briefly presents two computational studies involving aluminyl compounds. Mechanisms for the 1,4-bis activation of benzene by monomeric and dimeric aluminyl anions are examined and compared with experiment. In addition, the steric and electronic properties of a series of iron-aluminium compounds are investigated using computational methods for quantifying ligand environment and accessibility, as is presented in the two associated publications. Collectively, the investigations described throughout this thesis demonstrate how synthetic chemistry and modern computational methods can be used in concert to explain and predict low-valent main-group chemistry. The work expands the known chemistry of low-valent compounds of Groups 13 and 14 through the synthesis and characterisation of new molecular species, investigation of unusual electronic structures, and the elucidation of reaction mechanisms that are otherwise experimentally inaccessible. These studies contribute to the growing understanding of how low-valent main-group compounds activate chemical bonds and access otherwise challenging reactivity.
Access status: Open Access ,
Eliciting Plasma Illumination as a Responsive and Relational Medium within Blown Glass.
(2026) Curtis, Harriet
This practice-led research investigates plasma illumination within blown glass as a responsive and relational medium through creative practice. Unlike the distant spectacle of auroras or lightning, plasma illumination invites proximal engagement with these phenomena. Drawing on the dual etymology of plasma, as both the luminous fourth state of matter and a vital component of blood, the illuminated objects and installations created through this research evoke circulatory pathways as a metaphor for connection and presence. Using a diffractive methodology, I combine techniques from glassblowing, neon fabrication, and scientific glass working to make a plasma vessel. I draw upon the tripartite process known in the neon lighting trade as "processing", which involves: 1) glass vessel formation; 2) atmospheric manipulation; and 3) electromagnetic activation. I subject this tripartite process to a craft-intensive methodology that I describe as leaks and tangles. Subsequently, the varied interior surface of the vessel actively contributes to the plasma's behaviour, while the glass's transparency allows those behaviours to remain visible. Informing this doctoral project are interviews with eleven international plasma illumination practitioners, documenting the language of makers alongside field research examining histories of scientific apparatus. Resonant with the relational interpretation of quantum mechanics, the principle that phenomena emerge through interactions rather than existing as isolated entities, I reframe plasma illumination as a relational medium. Through iterations of encasing plasma phenomena within glass objects and installations, the artworks demonstrate oscillatory behaviours in relation to the glass surface and the viewer's proximal engagement, revealing our otherwise unperceived interconnectedness.

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