http://theses.ncl.ac.uk/jspui/handle/10443/73 2026-05-27T00:58:21Z http://theses.ncl.ac.uk/jspui/handle/10443/6793 Title: Structure and surface energy of blend films of Polystyrene and Polybutadiene Authors: Ibrahim, Mai Salem Y Abstract: This thesis presents data on the structure and morphology of spin-coated films of different blends of polystyrene (PS) and polybutadiene (PB). It is shown that there is a complex interrelationship between surface tension, molar mass, and film roughness that makes predicting and understanding the final morphology difficult. Both depth profiling (time-of-flight elastic recoil detection and Rutherford backscattering, as well as some cross-sectional transmission electron microscopy) and surface imaging (atomic force, optical, X-ray photoelectron, and electron microscopy) have been used alongside contact angle measurements to elucidate the three-dimensional nature and properties of these films. Spin coating is a widely employed technique for producing uniform thin films, prized for its simplicity, speed, and cost-effectiveness. It allows for precise control over film thickness by adjusting parameters such as spin speed and solution viscosity. This method is compatible with a range of materials, enhancing its versatility for both research and industrial applications. Furthermore, spin coating yields smooth and homogeneous films, making it ideal for optical, electronic, and surface-related studies. The polystyrene/polybutadiene (PS/PB) blend offers significant advantages for thin film fabrication, owing to its tunable phase separation behaviour that enables controlled microstructure development. The immiscibility of the two polymers facilitates the creation of well-defined morphologies, which can be tailored for specific applications. Moreover, the mechanical flexibility of PB effectively complements the rigidity of PS, resulting in films with well-balanced mechanical properties. This blend also demonstrates favourable film-forming characteristics during solution-based processes, such as spin coating, thereby enhancing reproducibility and uniformity. The study found that surface segregation cannot be predicted solely based on surface energy. Both polystyrene (PS) and polybutylene (BP) tend to migrate to the air or substrate interface, depending on their molar mass. Notably, polystyrene with a lower molar mass shows a preference for the surface. Description: Ph. D. Thesis. 2025-01-01T00:00:00Z http://theses.ncl.ac.uk/jspui/handle/10443/6792 Title: Self Interacting Fuzzy Dark Matter and its Observational Implications Authors: Indjin, Milos Abstract: We investigate aspects of Fuzzy Dark Matter (FDM) in both the non-interacting and repul sively self-interacting regimes, critically discussing the role of interactions on virialised profiles, using our findings to fit to galactic rotation curves of a range of dark matter dominated galax ies, thus proposing a way to numerically reconstruct a galaxy from analysing observational curves. Specifically, we firstly analyse the ground state solution of the Gross-Pitaevskii-Poisson equations- the soliton core. A generalised ansatz is formed along with a soliton-specific di mensionless interaction strength. The virial theorem is utilised to explain core dependencies on boson (m) and total mass, and self-interaction (g), and a degeneracy in the pairing of m and g is also uncovered. Moreover, we introduce a Super-Gaussian profile from empirically fitting to numerically generated self-interacting soliton ground states. This profile, joined with a Navarro-Frenk-White (NFW) halo profile, is used to fit self-interacting FDM to observational data of dark matter dominated galaxies, finding the crucial result that a single m and g pair fits all selected galaxies. Thirdly, we present three dimensional (3D) simulation results of self interacting FDM, and we demonstrate a scheme which allows us to reconstruct density profiles whose inferred rotation curves replicate observational data. In particular, we present a sim ulated self-interacting FDM halo corresponding to a galaxy for which we have observational data, specifically galaxy UGCA444. We find an elegant form of the core-halo mass relation, depending on the total energy of the system and qualitatively comment on the variation in granule number and size depending on total energy. Next, we analyse the dynamical aspects of the halo. In particular we (i) investigate the effects of m and g on the oscillation frequency of soliton cores; (ii) reveal evidence for a cooling (condensation) process, where the core density grows on time scales longer than the age of the universe; (iii) finally, we undertake a preliminary investigation of the orbital dynamics of test particles in our recreated galaxy, commenting on the velocity dispersion and the implications for the age gradient of stars in disc galaxies. Description: Ph. D. Thesis. 2025-01-01T00:00:00Z http://theses.ncl.ac.uk/jspui/handle/10443/6789 Title: Desiccation Cracking: A Weather-driven Deterioration Phenomenon Affecting Infrastructure Slope Resilience Authors: McConnell, Emma Louise Abstract: Weather-driven deterioration of infrastructure embankments is an increasingly severe threat to their stability, longevity, and safe operation. Dry-wet cycles within compacted clay fill instigate shrinking and swelling, forming micro- and macro-scale cracks that drive irrecoverable microstructural changes. This degradation reduces the clay fill’s water retention capacity, exacerbating the rate, magnitude, and consequence of these dry-wet cycles. Therefore, understanding the timescales of microstructural degradation and desiccation cracking’s role within this is crucial to ensure the long-term serviceability of the transport network. Laboratory tests, while informative, often fail to capture field scale heterogeneity. To bridge this gap, an intermediate-scale, compacted clay slope was constructed within an outdoor lysimeter. This novel approach provided high-resolution spatial and temporal monitoring, revealing that cracking severity depends on exposure to physical and environmental boundary conditions. Desiccation cracks significantly altered slope hydrology, locally deepening evaporation and infiltration fronts by up to 400 mm and extending weather-driven deterioration to 200 mm. Deep summer crack networks (2021-2022) markedly increased rainfall storage capacity, allowing full infiltration of three simulated 1-in-100-year storm events (each delivering 52 mm of rainfall in one hour, with climate change uplifts applied) and producing no runoff. The resulting soil moisture increase resulted in a sharp decrease in suction, culminating in complete suction loss by the end of the third event. In contrast, shallower crack networks in Spring 2023 generated runoff under the same storm profiles. Seasonal drying patterns were also disrupted, maintaining high moisture contents that suppressed suction generation and inhibited deep cracking observed in prior summers The lysimeter slope enabled real-time monitoring of desiccation drivers, informing targeted laboratory-scale tests. These experiments provided insight into how altering the physical and environmental boundary conditions through modifying parameters in the Penman-Monteith (1965) equation can influence moisture transfer dynamics and desiccation behaviour within Ampthill Clay fill. Overall, this research qualitatively and quantitatively underscored desiccation as a key accelerator of weather-driven deterioration. Furthermore, it emphasised that all contributing elements to desiccation must be considered to fully assess their risk to infrastructure embankment stability. Description: Ph. D. Thesis. 2025-01-01T00:00:00Z http://theses.ncl.ac.uk/jspui/handle/10443/6787 Title: Assessing pedagogic benefits of the virtual world to enhance fieldwork Authors: Maddison, Janine Abstract: This research explores the evolving landscape of fieldwork practice, particularly the integration of digital tools in Higher Education (HE) fieldwork within the biosciences. Informed by expert panel interviews, a facilitators of fieldwork survey and student focus groups, the study examines the purpose of both traditional in-field approaches and emerging digital fieldwork practice. A fieldwork taxonomy is presented within this research, which uses pedagogic approach and delivery mode to define fieldwork practice. It investigates the role students can play in co-designing digital tools to address specific pedagogical challenges in fieldwork. Using an iterative design process, the research develops a Digital Field Notebook (DFN), Digital preparation resources, and a Virtual Field Trip (VFT). Student feedback is also used to exemplify the Technology Pedagogic and Content Knowledge (TPACK) framework to support the integration of technology in fieldwork. Additionally, expanding upon the role of student partnership, this research examines the feasibility of working with students to design, develop and deliver low-cost live fieldwork broadcasts. In evaluating the co-production partnership valuable insights into skill development and the future role of live broadcasting in fieldwork are shared. Despite students being involved in developing the DFN and recognising the benefits of this digital tool, barriers to the digital tools, barriers to their adoption within biosciences fieldwork remain. Recognising the need for practitioner training to address knowledge and skills gaps when adopting digital tools and the potential for adopting open scholarship practice, the digital tools were shared with the wider fieldwork community as Open Education Resources (OERs) during participatory workshops. These workshops played a key role in disseminating the tools, increases knowledge of the digital tools with participants, facilitating collaboration among attendees, fostering new ideas and supporting the integration of digital tools in fieldwork practice. Description: Ph. D. Thesis. 2025-01-01T00:00:00Z