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Electron Microscopy of Crystalline Phases and Solid Solution Behaviour in Model Leaf Waxes and Molecular Crystals
Get PDFMolecular organic crystals are widely used for applications in the pharmaceutical and agrochemical sectors. These crystals are often formed as part of a mixture of molecular components, forming co-crystals and solid solutions which impacts properties such as solubility and dissolution rates. Solid form molecular mixtures may give rise to chemical as well as structural heterogeneity across length scales. Understanding the nanoscale structure of these materials is therefore important to understand the resulting properties, physical or mechanical, in the development of new products for application as pharmaceuticals and agrochemicals. Many techniques traditionally used to characterise the structure of these systems are limited when it comes to the analysis of heterogeneity at the nanoscale. Scanning transmission electron microscopy (STEM) and specifically scanning electron diffraction (SED) is an emerging technique that offers high spatially resolved structural information at low electron doses, whilst associated spectroscopic methods can offer information on chemical heterogeneity. In this thesis SED and spectroscopic STEM-based techniques are used to study two organic solid solution systems; a replica leaf wax system of an n-alkane (n-hentriacontane, C31H64), and an n-alkanol (1-triacontanol, C30H61OH), and a barbituric acid (BA) and thiobarbituric acid (TBA) solid solution system for pharmaceutical applications.
This work first reveals the microscopic structure and heterogeneity of the replica leaf wax models based on the dominant wax types in the Schefflera elegantissima plant, namely C31H64 and C30H61OH and their binary mixtures. SED reveals grain microstructure in C31H64 crystals and nanoscale domains of chain-ordered lamellae within these grains. Moreover, nematic phases and dynamical disorder coexist with the domains of ordered lamellae. C30H61OH exhibits more disordered chain packing with no grain structure or lamellar domains. Binary mixtures from 0–50% C30H61OH exhibit a loss of grain structure with increasing alcohol content accompanied by increasingly nematic rather than lamellar chain packing, suggesting a partial but limited solid solution behaviour. Together, these results unveil the previously unseen microstructural features that may govern flexibility and permeability of leaf cuticles.
Analysis then turns to studying the impact of exposing these waxes to an external molecule, tris(2-ethylhexyl)phosphate (TEHP) commonly used as an adjuvant to promote uptake of crop protection molecules after topical application of a spray to a leaf. A combination of bulk techniques (X-ray diffraction (XRD), differential scanning calorimetry (DSC)) and electron microscopy techniques at different wax to TEHP concentrations suggest possible etching and dissolution mechanisms that disrupt the crystalline paraffin wax structures, with a greater effect seen in the interaction with the n-alkanol chains than the n-alkane chains. Wax crystal plane facet analysis by SED confirms the increased loss of material at crystal plane faces with a higher proportion of alcohol groups presenting at an exposed surface. In the paraffin wax solid solution system, spectroscopic techniques fail to differentiate the two wax components.
Finally, SED with elemental spectroscopy, energy dispersive X-ray spectroscopy, (EDS) is used to characterise the BA / TBA molecular alloying system prepared from ethanol solvents, where the two component molecules are similar except where a sulphur atom has replaced an oxygen atom in the TBA. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) suggest the components form a solid solution over the range of 20 – 70 % TBA content albeit with some hydrate formation too. EDS is used to quantify increasing TBA content up to ~60 % TBA, above which additional sulphur (TBA) content cannot be differentiated due to the increasing Bremsstrahlung background contribution it makes to the EDS.
The SED implementation of 4D-STEM has been shown to reveal microstructural features within a molecular solid solution that are not accessible by bulk techniques (such as changes in grain orientation, order and disorder at the nanoscale and dislocations). SED also has the potential to explore the importance of functional groups in solid solution formation, interaction with external molecules, and how impurities may affect solid solution form and stability (for example hydrate formation). Together this work opens up new prospects for the wider study of molecular crystal, solid solution systems
John Dewey and the ‘Orient’: Pedagogical Progress
No full textThe aim of this research was to find alternatives to modern/colonial educational philosophies, which have been central to sustaining the current hegemonic world order. To do so, it was necessary to interrogate how colonial narratives became embedded in educational structures and how education functioned as a key medium for disseminating the coloniser’s epistemologies. As notions of progress, civilisation, Westernisation, and modernisation have long shaped dominant educational aims, this thesis explores how modernisation reforms have served as vehicles for implementing and sustaining modern/colonial logic across different socio-political contexts.
Focusing on John Dewey and his visits to Japan, China, and Turkiye between 1919 and 1925, the research uses these cases to illustrate how educational modernisation intersected with coloniality. Dewey’s pragmatist philosophy influenced each country’s educational trajectory at distinct historical junctures, while the local conditions and ideological tensions in these societies simultaneously shaped his evolving perspectives on race and culture. Although Dewey’s early pedagogical practices reflected linear historicism and cultural hierarchy, his later concepts—particularly togetherness and knowledging—are revisited in this study as philosophical tools with decolonial potential.
This research also contributes to decolonial philosophies of education by placing Dewey’s lesser-studied concepts into conversation with epistemological decolonisation. Togetherness challenges cultural hierarchies by fostering relationality without centring the West, while knowledging critiques passive models of knowledge and promotes epistemic plurality. By positioning China, Japan, and Turkiye in relational dialogue, this thesis expands the decolonial framework beyond Latin America and the Global South, and calls for a reconceptualisation of educational futures grounded in intercultural understanding and epistemic justice
Agricultural Innovation in Sub-Saharan Africa: A Socio-Political Case Study of Push–Pull Technology and Biocontrol in Kenya
No full textAgricultural innovation is vital for addressing sub-Saharan Africa's food insecurity, land degradation, and climate change challenges. Biocontrol technologies have been developed and promoted as sustainable pest management methods to help achieve food security, protect the environment, and reduce poverty. Despite strong experimental evidence, their widespread adoption has not met the expectations of developers. Push–Pull Technology (PPT), developed by the International Centre of Insect Physiology and Ecology (ICIPE), exemplifies this gap between research success and large-scale implementation. While biocontrol solutions have garnered scientific and development interest, they are often viewed through a linear, technology-focused perspective that overlooks the social, political, and institutional factors shaping their utilisation.
To address this gap, the thesis considers agricultural innovation as a socio-political process rather than merely a technical one. It explores why promising biocontrol innovations such as PPT have yet to be adopted by millions of farmers across Africa and how pathways to innovation can become more inclusive and sustainable. The study employs a multi-scalar approach that combines a systematic review of literature, ethnographic research in Western Kenya, and an analysis of policy and institutional landscapes to connect farmer experiences with broader systemic contexts.
Drawing on Science and Technology Studies, political ecology, and innovation systems thinking, the thesis presents a synthesis of micro- and macro-level innovation dynamics. It proposes pathways towards more participatory, context-aware, and policy-aligned agricultural development in sub-Saharan Africa
Evaluating the Impact of a Wellbeing Focused Approach to a Tier 2 Adult Weight Management Service on Health Outcomes, Psychological Wellbeing, and Health-Related Behaviours
No full textIntroduction: Obesity is recognised as a significant health concern within the UK, and traditional weight management services have not demonstrated long-term improvements in health or reductions in weight. In response, some services are attempting to balance weight loss with broader wellbeing goals, however, the effectiveness of wellbeing‑focused models remains limited.
Aims: To evaluate the effectiveness and implementation of Feel Good Suffolk’s Healthy Weight pathway, a wellbeing-focused Tier 2 weight management service, to understand the mechanisms through which it operates, and the impact on service users.
Methods: A convergent mixed methods design combined routine outcomes for 1,097 adults with semi‑structured interviews with service users (n = 15) and stakeholders (n = 9). Linear mixed models assessed change in service user weight, body mass index (BMI), wellbeing (SWEMWBS) and physical activity (IPAQ). Reflexive thematic analysis explored experiences and service design.
Results: Weight (‑0.015 kg day⁻¹) and BMI (‑0.005 kg m⁻² day⁻¹) declined modestly (p < .001), whilst Wellbeing (+0.004 points day⁻¹; p = .084) and activity (+0.001 categories day⁻¹; p < .001) remained stable. Gender and disability moderated weight change, with small effect sizes. Thematic analysis revealed that service users identified a supportive scaffold of psychological safety, personalised goals and gentle peer accountability that made incremental change towards health and weight loss feel manageable. Weight loss remained central to the conversations, despite stakeholder attempts to widen the focus with a “healthy weight” reframe. Both groups acknowledged the impact of wider determinants of health, and stakeholders explained how the service plans to address them.
Discussion: Feel Good Suffolk delivers statistically reliable, yet clinically modest, weight reduction, a profile consistent with its wellbeing ethos. Its distinctive contribution lies in a psychologically safe climate that nurtures small, sustainable habit changes, leading to identity shifts. To maximise long-term impact, Tier 2 services should pair this psychologically informed design with extended follow up and outcome measures that identify health gains beyond weight
Electrical Impedance Spectroscopy for Particle Size Characterization in Colloidal Suspensions: Modelling, Measurement, and System Implementation
No full textBritish Theatre and Feminism from Clemence Dane to Gordon Daviot, 1921–1935
Get PDFThis thesis focuses on largely forgotten plays by British women authors—Clemence Dane, Fryn Tennyson Jesse, Marie Stopes, G. B. Stern, Aimée Stuart, and Gordon Daviot—who wrote for London’s West End theatres between 1921 and 1935. It analyses and contextualises their plays to investigate how middle-class women’s struggles in the domestic sphere and feminist concerns prevalent during the interwar period were represented on stage. I argue that those playwrights, sometimes dismissed as conventional and apolitical, embody in their works a subtle yet significant form of feminism. I focus on plays featuring women who bravely challenge social conventions but partially or entirely fail to break free and, in doing so, I trace how these plays question the limits of the ‘so-called’ emancipation that women enjoyed following the First World War and the suffrage movement and illustrates a tentative form of feminism that appreciates the value of small acts of resistance while acknowledging their shortcomings. The middlebrow canon under discussion employs the drawing-room play’s conventions, which heavily rely on intricate marriage plots. In Chapter One, I examine A Bill of Divorcement (1921) by Clemence Dane and The Pelican (1924) by Fryn Tennyson Jesse and H. M. Harwood and tackle their depiction of divorce and its implications for women’s liberation. Chapter Two analyses Our Ostriches (1923) and Vectia (1926) by Marie Stopes and explores their portrayals of sex education and birth control. Chapter Three focuses on The Man Who Pays the Piper (1931) by G. B. Stern and Nine Till Six (1930) by Aimée and Philip Stuart and their representation of marriage and career as polarised choices for women. Finally, Chapter Four considers The Laughing Woman (1934) by Gordon Daviot and Wild Decembers (1933) by Dane, which feature creative women in history and the barriers to their artistic expression
Characterisation and Assessment of Ultrasonic-Assisted Drilling in Thermoplastically Toughened Carbon Fibre-Reinforced Epoxy Composite
No full textThis work investigates the application of ultrasonic-assisted drilling (UAD) to aerospace-grade carbon fibre reinforced plastic (CFRP), with focus on process characterisation, force response, tool wear, and hole quality. A key output is the development of a novel measurement method whereby tool vibration amplitude was quantified using a high-speed camera and bespoke MATLAB software to track a datum feature etched on the drill tip. This enabled direct observation of micron-level displacement at ultrasonic frequencies and was successfully applied both out-of-cut and during drilling.
Quantitative assessment of drilling performance was carried out through force measurement, three-dimensional tool wear analysis, and analysis of drilled holes. Force data showed that ultrasonic assistance produced a consistent reduction in thrust force relative to conventional drilling, with reductions of 5–10% in the early stages of tool life and up to 20–40% at steady state. These reductions were observed across 300 holes per condition, demonstrating sustained process benefit. Tool wear analysis revealed that while ultrasonic excitation introduced a more aggressive wear mechanism initially, overall wear behaviour was comparable to conventional drilling after extended cutting. The onset of coating failure was shown to strongly influence instantaneous force response.
Hole quality assessment demonstrated that ultrasonic assistance can deliver improvements in dimensional accuracy. All ultrasonic frequencies maintained hole diameters within tolerance, with improved stability in circularity and cylindricity compared to conventional drilling. Uncut fibres were observed at hole exit in isolated cases, though these did not prevent compliance with aerospace drilling standards.
Collectively, the work establishes that ultrasonic assistance offers tangible benefits in CFRP drilling, including up to 40% reduction in thrust force, improved dimensional consistency, and a potential route to extended tool life. The novel amplitude measurement technique provides a reliable means of quantifying tool-tip amplitude during in-process cutting, advancing the industrial readiness of UAD for aerospace applications
A Full-Plant, Physics-Aware Approach to the Planning and Control of Multi-Robot Nuclear Fusion Maintenance Systems
Get PDFNuclear fusion holds great potential as a clean, high-tech energy source. However, fusion is impeded by myriad challenges across multiple domains: plasma physics, plant engineering, commercial viability, et cetera. Of these, the maintenance of fusion power plants presents a complex challenge which is deeply coupled to both the physics and the economy of the plant: how do we safely maintain such a large and complex nuclear environment in a manner that allows fusion to move beyond a scientific experiment to become a economically-viable source of power? In this thesis, we explore the feasibility of applying autonomous multi-robot systems to the fusion maintenance problem. In so doing we conduct extensive literature reviews of the fusion state-of-the-art, as well as that of fusion maintenance specifically, and discover significant historical trends and underlooked challenges which will define the priorities of the upcoming 'demonstrator generation' of fusion power plants (i.e. those which aim to demonstrate commercial viability). We then propose and implement a method of scaling the task scheduling of safety-verified, multi-robot systems to the sizes required by a future tokamak such as EU-DEMO. Finally, we introduce two complementary methods to analyse plasma disruptions under the presence of magnetic coil failures using the JOREK-STARWALL plasma simulation code, and subsequently synthesise a control policy for a 'plasma-gnostic' fusion maintenance system to accelerate maintenance in critical scenarios
Atmospheric microplastics and the human lungs
Get PDFMicroplastics (MPs) are an emerging environmental contaminant (EEC), that have recently been isolated from samples collected from the atmosphere, and are considered ubiquitous on Earth. There is a lack of knowledge regarding the properties of atmospheric MPs (AMPs), in terms of location, concentrations, plastic types, sizes and shapes. There is also limited understanding of the potential for these MPs to be inhaled, and the consequences of such exposure. Standardised approaches throughout the AMP field are called for, because incomparable datasets and varying microplastic (MP) definitions are slowing down the progression of research. It is now necessary to thoroughly investigate AMPs, and gain knowledge of the location and MP types relevant to human exposure, as well as assessing MP inhalation as an exposure route for humans. This information can direct future investigations into the potential hazards associated with AMP inhalation.
This thesis presents 3 publications, within this publication style thesis; investigating indoor AMPs, outdoor AMPs and a final investigation into the presence of MPs within human lung tissue samples, acquired from living patients
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