VictorJuiz/thesis huggingface dataset:
The sacred history of early Islamic Medina: the prophet, caliphs, scholars and the town's Ḥaram
Keywords: Islamic history
Saudi Arabia
Arabic historiography
sacred space
Medina

This thesis investigates the emergence of Medina in the Ḥijāz as a widely-venerated holy city over the first three Islamic centuries (seventh to ninth centuries CE) within the appropriate historical context, with special attention paid to the town’s ḥaram. It focuses in particular upon the roles played by the Prophet Muḥammad, Umayyad and Abbasid caliphs, and early Islamic legal scholars in this development. It shows that Medina’s emergence as a widely-venerated holy city alongside Mecca was a gradual and contested process, and one that was intimately linked with several important developments concerning legitimate political, religious, and legal authority in the Islamic world. The most important sources for this study have been Medina’s local histories, and Chapter One investigates the development of a tradition of local history-writing there. The Prophet Muḥammad first created a form of sacred space, a ḥaram, at Medina, and Chapter Two seeks to provide the context for this by investigating some forms of sacred and protected space found in the pre-Islamic Arabian Peninsula. Chapter Three then examines a rare early document preserved in the later Islamic sources, which deals in part with Muḥammad’s creation of Medina’s ḥaram, the so-called “Constitution of Medina”, and investigates why and how Muḥammad created that particular form of sacred space at Medina. The remaining two chapters deal with the history of Muḥammad’s ḥaram at Medina after his death as its original raison d’être disappeared. Chapter Four analyses some aspects of Muslim legal scholars’ discussions concerning Medina’s ḥaram, and demonstrates that certain groups disputed its existence. Chapter Five then seeks to understand why caliphs and other scholars invested so heavily in actively promoting its widespread veneration and Medina’s status as a holy city. It concludes that caliphs from the late first/early eighth century patronised Medina to associate themselves with legitimate political authority inherited from Muḥammad, and that from the late second/eighth century certain legal scholars argued for the continued existence of Medina’s ḥaram because of its association with the Prophet and his Companions who had come to be for them the ultimate source of legal authority.
Studies of a ‘blue’ copper oxidase electrocatalyst
Keywords: copper
spectroelectrochemistry
Laccase
electrocatalysis
surface modification
oxygen reduction reaction
enzyme

This thesis concerns the electrochemical investigation of high-potential laccases. These multicopper oxidases are efficient electrocatalysts for the dioxygen reduction reaction.
A method for stabilising laccase on a graphite electrode was established. The method involved modification of the graphite surface by diazonium coupling of a 2-anthracene molecule. A laccase ‘film’ adsorbed on this modified surface remained stable for over two months and, typically, the current density for dioxygen reduction was doubled compared to a laccase ‘film’ on an unmodified surface.
Protein film voltammetry was used to investigate thermodynamic and kinetic aspects of the electrochemical behaviour of laccase. The effect of inhibitors on the magnitude of reduction current and the position of the wave (related to the overpotential for the reaction) was also studied. Fluoride, chloride and azide showed different modes of inhibition and inhibition constants ranged from micromolar for azide to millimolar for chloride.
In cyclic voltammetry experiments it was only in the presence of high concentrations of the inhibitors fluoride, chloride and azide that a non-turnover signal, corresponding to a one electron transfer process, was revealed. The evidence suggested that the non-turnover signal arose from interfacial electron transfer between the electrode and the type 1 or ‘blue’ copper. Evaluation of the peak areas allowed determination of the catalytic rate constant, kcat, as 300 s–1, and the electroactive surface coverage as four pmol cm–2. The rate of interfacial electron transfer was rapid enough to not limit catalysis at high overpotentials.
A spectroelectrochemical cell was designed to investigate the behaviour of the type 1 copper in the presence of inhibitors and at different pH values. The inhibitors fluoride, chloride and azide had little effect on the reduction potential of the type 1 copper, but at higher pH values the reduction potential of the type 1 copper was decreased.
Exponential asymptotics and free-surface flows
Keywords: free-surface flows
asymptotic approximations
gravity-capillary waves
water waves
ship hydrodynamics
exponential asymptotics

When traditional linearised theory is used to study free-surface flows past a surface-piercing object or over an obstruction in a stream, the geometry of the object is usually lost, having been assumed small in one or several of its dimensions. In order to preserve the nonlinear nature of the geometry, asymptotic expansions in the low-Froude or low-Bond limits can be derived, but here, the solution invariably predicts a waveless free-surface at every order. This is because the waves are in fact, exponentially small, and thus beyond-all-orders of regular asymptotics; their formation is a consequence of the divergence of the asymptotic series and the associated Stokes Phenomenon.
In this thesis, we will apply exponential asymptotics to the study of two new problems involving nonlinear geometries. In the first, we examine the case of free-surface flow over a step including the effects of both gravity and surface tension. Here, we shall see that the availability of multiple singularities in the geometry, coupled with the interplay of gravitational and cohesive effects, leads to the discovery of a remarkable new set of solutions.
In the second problem, we study the waves produced by bluff-bodied ships in low-Froude flows. We will derive the analytical form of the exponentially small waves for a wide range of hull geometries, including single-cornered and multi-cornered ships, and then provide comparisons with numerical computations. A particularly significant result is our confirmation of the thirty-year old conjecture by Vanden-Broeck & Tuck (1977) regarding the impossibility of waveless single-cornered ships.
The dynamics, stability and manifestation of circumbinary orbits
Keywords: circumbinary
stars
binaries

I numerically investigate the dynamics of orbits in 3D circumbinary phase-space as a function of binary eccentricity and mass fraction. I find that inclined circumbinary orbits in the elliptically-restricted three-body problem display a nodal libration mechanism in the longitude of the ascending node and in the inclination to the plane of the binary. I analyse and quantify the behaviour of these orbits and investigate their stability over time. This work is the first dynamically aware analysis of the stability of circumbinary orbits across both binary mass fraction and binary eccentricity. This work also has implications for exoplanetary astronomy in the existence and determination of stable orbits around binary systems.
I also present an examination of the so-called radio ruff around the microquasar SS433, which I show to precess on a timescale of approximately 550 days. The observed precession in the projected angle of the ruff on the sky may be explained if the ruff feature arises from an inclined circumbinary excretion disk. In addition, I describe a pilot study in the near-infrared waveband in search of circumbinary material around other microquasars.
The contextual evaluation framework: a prototype evaluation technique for e-Research
Keywords: workplace studies
ethnomethodology
requirements engineering

The contextual evaluation framework (CEF) is a requirements engineering technique that incorporates a particular sociological orientation, Ethnomethodology, in the development of a rigorous and systematic approach for requirements elicitation. This qualitative approach examines how well a system may be aligned with the endogenous organisation of work within a community of practice. Assessing how well a system supports the knowledge, skills and practices that already exist within a community is equally as important as developing solutions that will eventually reconfigure those practices, create new ones and extend modes of collaboration. The aim of this thesis is to address the absence of a systematic approach to quasi-naturalistic prototype evaluation which may be useful to a broader community such as requirements engineers, computer scientists and others not familiar with the details of sociological approaches. Such an aim is in line with the ways in which prototype evaluation approaches, particularly in HCI, have successfully been disseminated throughout the computer science research community - with the provision of guidelines. Likewise, the CEF is conceived of to be implemented in a similar manner.
Its focus is on the analysis of a prototype’s relevance as a tool that is in some manner familiar to those who might use it. Specifically, professionals within a discipline share complex skills and knowledge where they learn to use similar tools, instruments and processes necessary for their work. Implicit in these social practices, practitioners gradually acquire the knowledge and skills necessary to become full members of a community of practice. In this way, the processes, objects and artefacts of practice come to possess specific meaning and significance. The CEF examines how this complex architecture of meaning is supported, constrained or transformed when using a prototype and makes possible an assessment of the ways in which participants interpret its usefulness and usability.
Magnetoencephalography and neuropathological studies of autism spectrum disorders and the comorbidity with epilepsy
Keywords: epilepsy
autism spectrum disorders
neurophysiology
magnetoencephalography
neuropathology
stereology

Autism spectrum disorders (ASD) are neurodevelopmental disorders with multiple neurobiological aetiologies, which could be genetic, structural, metabolic or immune-mediated. ASDs are diagnosed with deficits in social communication and restricted and repetitive behaviours, and are associated with sensorial atypicalities. 30% of cases have co-existing epilepsy. A series of in vitro, in vivo and post-mortem investigations were undertaken to examine sensory atypicalities in ASD.
In vitro characterisation of hippocampal neuronal cultures using immunofluorescence demonstrated the presence of multiple cell types including neurons, astrocytes and microglia. The distribution of ion channels of the Shaker family and tumour necrosis factor α receptors in astrocytes and neurons were identified but not explored further.
Neuroanatomical and neuropathological investigations of primary olfactory cortex, using post-mortem stereology, demonstrated a specific increase in glial cell densities in layer II, which was negatively associated with age in ASD. Increases in glia were also associated with symptom severity and often co-localised with the presence of corpora amylacea in layer I. Qualitative analysis of the olfactory tubercle demonstrated that corpora amylacea did not extend to this neighbouring region of the primary olfactory cortex in ASD. These changes were independent of co-existing epilepsy and not observed in epilepsy without ASD. Preliminary pilot studies of the hippocampus provided a stereological sampling strategy to quantify cell densities in future investigations of this area in ASD.
Neurophysiological investigations using collected magnetoencephalography data demonstrated diminished occipital gamma oscillatory synchrony in ASD in a visual time perception task. This did not always predict behavioural outcome but was specific to ASD and could not be explained simply in terms of changes in task performance. Moreover, changes in oscillatory synchrony were associated with symptom severity.
These observations in primary sensory domains in post-mortem tissue and in patients suggest possible novel mechanisms in ASD and extend knowledge of the neurobiological bases of these disorders.
Large area vacuum fabrication of organic thin-film transistors
Keywords: organic semiconductor
vacuum processing
flexible electronics

A process has been developed to make the dielectric layer for organic thin-film transistors (OTFTs) in a roll-to-roll vacuum web coater environment. This dielectric layer combined with an organic semiconductor layer and metal layer deposited in vacuum allows a solvent-free process to make organic/inorganic multilayer structures for thin-film electronic devices on a flexible substrate at, potentially, high speed.
The polymeric gate dielectric layers were fabricated by flash evaporation of acrylic monomers onto a polymer film with pre-patterned metal gates followed by radiation curing by electron beam, ultra-violent light (UV) or plasma. With a non-polar dielectric surface, charge carrier mobility (μ) of 1 cm2-V-1s-1; on/off curren ratio of 108, sub-threshold swing (SS) of 0.3 V/decade and saturated output curve were routinely achieved in dinaphtho-[2,3-b:2'3'-f]thieno[3,2-b]thiophene (DNTT) transistors with dielectric layer of tripropylene glycol diacrylate (TPGDA) of ~400 nm.
Apart from the TPGDA, monomer formulas including 1,6-Hexanediol diacrylate (HDDA) as well as several commercial acrylic resins have been used to make the dielectric layer. The highest areal capacitance of 41nF-cm-2 was achieved with a pin-hole free film of less than 100 nm made of an acrylate mixture resin.
A non-polar dielectric surface treatment layer has been developed based on flash evaporation of lauryl acrylate and HDDA mixture. The transistors with the buffer layer showed constant performance and a mobility fivefold greater than those of untreated samples.
The effect of humidity, oxygen, and light during switching cycles of both pentacene and DNTT transistors were studied. Water and oxygen/illumination had a distinct effect on both pentacene and DNTT transistors. Oxygen leads to acceptor-like charge traps under illumination, which shifted the turn-on voltage (Vto) to more positive values. In contrast, water in transistors gave rise to donor-like charge traps, which shifted the Vto and the threshold voltage (VT) more negatively. The DNTT devices showed good stability in dry air without encapsulation, while pentacene transistors degraded with either repeating measurement or long term storage. A DNTT transistor with a PS-coated TPGDA dielectric layer showed stable drain current (Id) of ~105A under bias stress of the gate voltage (em>V
g) of -20V and the drain voltage (em>Vd) of -20V for at least 144 hours. The Vto shift after the stress was less than 5 V and was recoverable when the device was kept in dry air for a few days. Possible reasons for the Vto shift have been discussed.
Natural and bioinspired silk spinning
Keywords: SEM
nephila edulis
spider
bombyx mori
fluid
silkworm
FTIR
silk

This thesis describes an investigation into silk spinning, with the objective of producing high performance silk fibres in the laboratory using a novel spinning device based upon observations on natural spinning glands and processes. After an in-depth literature review the work is reported in two sections: natural and artificial spinning. The literature provides fragmented data on different aspects of natural silk production, and artificial spinning has not yet reproduced fibres with the properties of native silk fibres, despite unfounded claims of biomimetic spinning.
The first half of the thesis looks at natural silk spinning. The work started with a general study of the morphology of spider and silkworm spinning ducts: First, how the silk fibre develops as the dope flows through the gland; and second the relationship between silk fibre properties and both gland morphology and spinning speed. More detailed studies using histochemical and spectroscopic investigations showed that the silk ducts of the spider Nephila edulis and the silkworm Bombyx mori both contain β-chitin, despite an evolutionarily distant common ancestor. Finally, observations showed that the duct of N. edulis consists of alternating nanoporous discs, and FEA modelling indicated that the duct is optimised for mechanical integrity and permeability.
The second half of the thesis describes the development of a spinning device that uses natural silk dope mainly taken from B. mori as feedstock. It begins with a description of the gradual development of the engineering aspects of the spinning device, to meet challenges raised during the spinning investigation. The development of a centrifugal capillary rheometer, for practical quantitative insights into rheological processes is then presented. Finally the spinning investigation is reported: first, the screening of spinning in glass capillaries based upon natural gland dimensions and flow rates, which have been shown to induce fibrillation in silk dope in a rheometer, and also included initiation of instability through heat applied along the capillary; second, the final spinning evaluation, using lessons learned from all the screening trials throughout the project, but also including a key development of a hydrophobic coating on the capillary tip to inhibit droplet formation and massively increase the process stability and ease of fibre production.
The main conclusions from this work are that good silk fibre cannot be spun by flow shear stress alone; and, that heat instability induces indiscriminate gelation of the silk, whose disordered molecular structure gives poor silk fibre properties. The body of work behind these conclusions provides fundamental background information and new insights that will contribute to the next stages of development of artificial silk spinning, from obtaining a better understanding of the biology of natural spinning glands to the engineering difficulties of implementing the bioinspired principles.
Catalytic asymmetric carbon-carbon bond formation using alkenes as alkylmetal equivalents
Keywords: Copper catalysis
Asymmetric Synthesis
Zirconium
Conjugate addition

The development of new methods for carbon-carbon bond formation is a challenging topic at the heart of organic chemistry. Over the past ten years a number of methods for the catalytic asymmetric 1,4-addition of organometallic reagents such as Grignard, organozinc and organoaluminium reagents have been reported. However these reagents suffer from many limitations, including the need for cryogenic temperatures, which prevent their widespread use. Here we have developed a new asymmetric method: the copper-catalysed enantioselective 1,4-addition of alkylzirconium compounds, generated in situ, from alkenes.
A general introduction into the formation of carbon-carbon bonds and catalytic asymmetric 1,4-addition reactions is first given. We then focus our attention on hydrometallation reactions and their current use in the addition of alkenyl and alkyl groups in asymmetric 1,4-addition reactions. In Chapter two, we introduce the development of our methodology. We found that by using copper complex (S,S,S)-A, high enantioselectivities can be achieved (up to 96% ee), in the presence of a broad range of functional groups which are often not compatible with comparable methods using pre-made organometallic reagents. The method gives good enantioselectivity at room temperature, in a wide range of solvents, using readily available alkenes.
Chapter three discusses the expansion of our method to the 1,4- and 1,6-addition to complex steroids. Modified conditions were then found to enable the addition to β-substituted enones, to form quaternary centres. This is followed by the successful addition to α,β-unsaturated lactones, another difficult substrate class. All these results gave excellent selectivity.
In summary, we have developed a new reaction which offers an alternative to current methods reported in the literature. This robust reaction can tolerate a variety of functional groups and we hope that this will aid in the synthesis of important molecules.
Beyond theatre regionalism: when does formal economic integration work in Africa?
Keywords: policy space
international political economy
issue linkages
Africa
regional economic integration

For the most part, formal economic integration between African states can be characterised as ‘theatre regionalism’: governments sign regional economic agreements with no intention to implement them. Yet amidst widespread theatre there have been a few instances of actual integration. This thesis sets out to explain this variance: under what conditions do African governments implement – and not just sign – formal agreements on regional economic integration? To answer this question the dominant Eurocentric literature on comparative regionalism is amended with insights from the third worldist literature on African states to develop a new approach for comparative analysis, the ‘Regionalism as Policy Space’ (RPS) framework. This framework models African regionalism as a two-stage game. At the first stage, governments’ interests in regionalism are determined by perceptions of the existence of structural cross-issue linkages connecting implementation of regional agreements with the widening of government policy space. Given such linkages, at the second stage, governments of a region engage in a coordination game to establish the distribution of benefits from integration. Variance in the implementation of regional agreements, then, is explained by variance in the existence of perceived cross-issue linkages (the Benefits Existence Condition) and the ability of participating governments to ease distributional tensions (the Benefits Distribution Condition). Four African customs union case studies - the East African customs union of the 1960s and 70s, the customs union of the East African Community in the 2000s, the customs union of the Economic Community of West African States and the Southern African Customs Union – lend strong empirical support to the RPS framework. The thesis ends with a discussion of the role of hegemons and proposes a series of policy measures aiming to reduce the likelihood of theatre regionalism in Africa.