VictorJuiz/thesis huggingface dataset:
Theoretical limits to tidal stream energy extraction

Tidal stream energy has gained attention as a source of predictable and renewable energy. Devices resembling underwater wind turbines, placed in fast tidal streams, have been proposed to extract this energy. Arrays of many such devices will need to be deployed to deliver a significant amount of energy to the electricity grid. One consequence of energy extraction is that the array provides a resistance to the tidal stream, which may change the local and far field hydrodynamics, which in turn affects the power available to the array. Array-scale hydrodynamic changes affect the flow presented to the devices, which in turn affects the total resistance the array provides to the flow. This thesis is concerned with the interactions between device, array, and the tidal stream resource, to better understand the power potential of turbine arrays.
Linear momentum actuator disc theory is employed to describe the operation of an idealised turbine array partially spanning a wide channel. The model is comprised of two quasi-independent sub-models, an array-scale model, describing flow phenomena around the array, which provides the upstream boundary condition to the device-scale model, describing the flow around a device. The thrust applied by the array is the sum of the thrust applied by the devices, completing the sub-model coupling.
The numerical simulation of arrays in depth-averaged simulations is then investigated using the two-scale concept developed in the analytic partial-array model. It is shown that the device-scale flow must be modelled with a sub-grid scale model in order to correctly describe the unresolved device-scale flow and hence estimate the power available to an idealised array. Turbulence modelling in depth-averaged simulations of turbine arrays is also discussed.
Temporal variations in tidal amplitude and strength mean that generator capacity will need to be economically matched to the available resource. As device performance may consequently depart from the relationship derived in idealised models when power capping is employed, blade element momentum theory is modified to parameterise tidal turbine performance during power capping. The array-scale effect of power capping is studied in depth-averaged simulations, in which it is shown that a significant reduction in device thrust may occur during power capping, reducing the impact of energy extraction from the tidal stream.

Keywords: Tidal Stream Turbines
Tidal Energy
Linear Momentum Acutator Disc Theory
Advisor: Houlsby, G
Willden, R
Sonic properties of silks

Silks are biomaterials made by spiders and silkworms, evolved for natural functions ranging from protection to predation. The research presented in this Thesis combines principles and methods from engineering, physics and biology to study the material properties of single silk fibres from a biological perspective. In particular, the factors that contribute to the variation in properties of single silk fibres are investigated. The first part of the Thesis focuses on silks made by silkworms. Whether naturally spun or forced reeled, the mechanical properties of these silks are sensitive to a range of environmental and processing conditions, such as humidity, stretching and reeling speed. The research presented in this section contributes to the understanding of how these applied conditions affect silk mechanical properties, which can be understood in terms of silk’s protein structure and biological context. The second section compares both silkworm and spider silk single fibres to other materials in terms of their sonic properties – how the materials propagate sound waves, whether following impact, or propagating vibrations. The results are discussed in the context of the silk’s natural function for impact resistance (silkworm cocoon or spider web) and vibrational signalling (spider silks). The Thesis ends with a discussion of how the presented techniques can be applied to help further our understanding of orb web function through studying spider silks. Overall, this interdisciplinary Thesis contributes to our understanding of the structure-property-function links of these fascinating biomaterials.

Keywords: silk
vibration
biomechanics
web
Advisor: Vollrath, F
Siviour, C
Holland, C
Town, crown, and urban system: the position of towns in the English polity, 1413-71

In this thesis, a collective urban sector-consisting, in various different guises, of civic governments, urban merchants, and townspeople-is presented as a vital and distinctive component of later medieval English political society. The dynamics of this urban political sector are reconstructed through the use of a modified version of the 'urban systems' approach found in historical geography and economic history, positing that towns are defined by their evolving relationship with one another. Drawing from the municipal records of twenty-two towns, this thesis charts the composition of the later medieval English 'urban system' and the manner in which urban groups belonging to this 'system' participated in a broader national political sphere over four chronological periods-1413-35, 1435-50, 1450-61, and 1461-71. In 1413-35, the highly authoritative and institutionalised governments of Henry V and the child Henry VI fostered vertical relationships between the Crown and a variety of individual civic governments, leading both national and urban political actors to operate within a shared political culture, but not necessarily encouraging inter-urban political communication. This would change in the periods that followed, as the absence of strong royal authority after 1435 renewed the strength of lateral mercantile networks and facilitated the re-emergence of a semi-autonomous inter-urban political community, which saw little reason to participate in the civil wars of the early 1450s that now seemed divorced from its own interests. In the 1460s, however, the financially extractive policies of Edward IV once again gave civic governments and ordinary townspeople a greater stake in royal government, which was reflected in the high level of urban participation in the dynastic conflicts of 1469-71. The developments occurring in these four phases illustrate both the interdependence of urban and national politics in the later medieval period, and the mutability of their relationship with one another.

Keywords: political culture
urban history
Wars of the Roses
networks
Advisor: Watts, J
Cultivating the heart: suffering and language in Ancrene Wisse, the Wooing Group, and the Katherine Group

This thesis examines the language of pain/suffering in Ancrene Wisse, the Wooing Group, and the Katherine Group, arguing that the anchoress nourishes an acute but discriminating sensitivity to pain. It seeks to demonstrate that the anchoress uses these early Middle English texts to cultivate sophisticated affective stirrings. Chapter 1 foregrounds the multidimensional penitence in Ancrene Wisse, situated in the context of Latin and vernacular penitential and homiletic material. The anchoress’ penitential processes demand not only physical pain, but also affective pain and intensive cognitive processes of self-examination. Chapter 2 argues that the Wooing Group meditations are tools of pain-cultivation, which the anchoress uses to nurture her affective pain as she develops her intimacy with the Spousal Lamb and his Mother. Chapter 3 assesses imagery of physical and affective woundedness. This chapter examines the anchoress’ use of imagery of Christ’s wounds, sin-wounds, and penitential wounding in Ancrene Wisse and the Wooing Group, and then studies her use of the saints’ wounding in the Katherine Group. Chapter 4 contends that spectatorship and performance of suffering are not separable acts for the anchoress. The chapter assesses: the anchoress’ spectatorship in the Katherine Group hagiographies, a spectatorship based on defamiliarization; the anchoress’ participation with the pain of Christ in Ancrene Wisse and the Wooing Group, including an examination of her potential use of church wall paintings; and the female reader of Hali Meiðhad, who immerses herself in the suffering of a married and child-bearing woman. Chapter 5 examines the crucial affective phenomenon of compassion, arguing that compassion in Ancrene Wisse and the Wooing Group is not a distanced ‘pity’, but a complex ‘co-feeling’ (using Milan Kundera’s (1984) term). The thesis concludes by underscoring the fact that the anchoress’ painful existence is not pathological; it is an existence characterized by agency and emancipation.

Keywords: literature
medieval spirituality
Advisor: Sutherland, A
Novel oxidatively activated safety catch linkers

Solid phase organic synthesis is a powerful technique to facilitate rapid synthesis and easy purification of organic compounds. The advancement of linkers and cleavage strategies is of paramount importance for the success of this approach. This thesis is concerned with the development of a robust safety catch linker system aimed to allow a broad range of commonly used reagents to be employed in a synthetic sequence carried out on a solid support.
Chapter 1 outlines the principles of solid phase organic synthesis, the terminology associated with this approach and the advantages and disadvantages compared to conventional solution phase methods. Common attachment and release strategies for various functional groups are described and the safety catch principle is introduced.
Chapter 2 discusses the design features of the linker system. Proof of principle is demonstrated for the attachment and release strategies with a simple solution phase model system.
Chapter 3 describes the adaptation of the linker system to the solid phase. Key transformations are modelled with solution phase experiments and subsequently applied to solid phase. The loading determination of the solid phase system is also described.
Chapter 4 reports an assessment of the reactivity of the linker system in the coupling transformation of aliphatic alcohols and amines. The chemoselectivity and efficiency of the CAN debenzylation/cyclorelease protocol is also evaluated.
Chapter 5 demonstrates the utility of the linker system with the optimisation of a simple synthetic sequence in solution followed by adaptation to the solid phase. The synthesis of a pilot library of aryl alcohols utilizing a Suzuki coupling on solid support is described. The attachment and release of amines is also demonstrated with solid phase examples.
Chapter 6 examines the potential of the linker system as an analytical tool to assess the outcome of stereoselective transformations. A chiral auxiliary is attached to the solid phase by aid of the safety catch linker and released into solution. A solution phase model system is developed to aid preliminary investigations in solution prior to adaptation to the solid phase.

Advisor: Davies, S
Japan and the peace and friendship treaties with Moscow and Peking

In August of 1978, Japanese and Chinese officials reached agreement on a Peace and Friendship Treaty which had been the subject of sporadic negotiations since the two sides normalised relations in 1972. But Japan also signed a Joint Declaration in 1956 with the Soviet Union, a bilateral agreement which also called for a future Peace and Friendship Treaty, which still has not been signed.
The first section of the thesis deals with domestic historical, political, economic and cultural factors which affect foreign policy in each of the three countries and which have particular bearing on the treaty negotiations. Major emphasis is placed on those developments which have affected national security, or which have a bearing on collective perceptions of national security, including the strength of the armed forces.
The second and longer portion of the thesis deals with Japan's bilateral relations with each of its two neighbours historically, and in more recent times in economic, political, military and cultural terms, and with key issues and developments in bilateral negotiations on the treaties. Throughout this section the primary focus is on Japan, its political parties and factions and the positions these have taken on the treaties and issues related to the treaties throughout the years. It also deals with the key issues dividing Japan and its negotiating partners on the two treaties, as well as Japan's 'equidistance policy' and 'its 'special relationship' with the United States.
Conclusions at the end of part one in Section Two include points about the special constraints imposed upon the USSR in its negotiations, the importance of fishing rights in the Russo-Japanese relationship, the impact of the Ussuri River incidents of 1969 on the policies of Moscow and Peking and the phenomenon of two separate foreign policy goals working at cross-purposes on both sides in the bilateral relations between Moscow and Tokyo.
Conclusions at the end of the thesis deal with the trilateral relationship and with such questions as why one treaty was signed and why the other has not been at this writing, whether there is any real substance to the new treaty, whether its signing is a setback to Soviet foreign policy and a threat to Soviet security and finally, what prompted Japan to abandon its 'equidistance policy'. The role of the White House and the State Department, and the question of how Japan came to be in the uncomfortable position of pawn or 'prize' in the Sino-Soviet rivalry are also examined.
Quantatitive analysis of type Ia supernova spectra and implications for cosmology

This thesis presents the spectroscopic observations of the Supernova Legacy Survey (SNLS) from the Gemini-North telescope from May 2006 – May 2008. During this time 68 of 95 targets were confirmed as Type Ia supernovae (SNe Ia) or classified as probable SNe Ia events. We use these objects and reanalyse other high-z spectra obtained as part of SNLS to search for signs of evolution in SNe Ia properties. To do this we use a multicolour method to remove host galaxy contamination from the high-z spectra and measure the equivalent widths of three spectral features in the rest-frame blue part of the spectrum: CaII H&K, SiII and Mg II. These are compared to a sample of low-z objects drawn from the literature. No evidence for evolution is found, but a change in the properties of the SiII feature is observed. This can be explained by changing supernova demographics, an outcome of the two-component progenitor model for SNe Ia.
The utility of SNe Ia supernovae for cosmology is confirmed and the possible use of spectral features as alternative calibrators is investigated. The equivalenth width of the SiII feature is anticorrelated with light curve stretch and this is used to define a "spectral stretch" from the low-z sample, which is used to reduce the scatter in the low-z sample. This holds promise for improving the calibration of high-z SNe Ia, particularly if new facilities are used to provide higher-quality spectra.

Keywords: cosmology
supernovae
Advisor: Hook, I
Non-equilibrium superconductivity in niobium and its application to particle detection

The propagation of non-equilibrium phonon and quasiparticle signals in bulk single crystal superconducting niobium has been investigated using superconducting tunnel junctions. Excitations generated by pulsed laser light and particle interactions were studied in 2-12 g crystals. At temperatures below 2 K the lifetimes of non-equilibrium phonons were found to be very much shorter that the theoretical bulk anharmonic decay times. Quasiparticle propagation was observed limited by impurity scattering. The proximity effect in Al thin films on Nb single crystal surface was studied. Particle interactions were detected in Nb with both position and energy resolution. The possibilities for using a detector based on superconducting single crystal niobium for a dark matter search are discussed.

Advisor: Salmon, G
Bismuth based thin film superconductors

This thesis describes investigations performed into the growth and characterisation of Bi-based (Bi2Sr2Can-1CunO2n + 4 + x, n=2, 3) ceramic superconducting material in the form of thin films, about 0.5μm thick, grown on single crystal MgO, LaAIO3 and SrTiO3 substrates by r.f. magnetron sputtering. The effect of oxygen content on the Pb doped Bi-2223 (n=3) phase was also studied by changing the cooling process and by annealing in different partial pressures of oxygen at ambient pressure.
The films produced have been assessed by considering their initial composition where it is found that Bi/Sr ratios can be between 0.9c- zero
of around 80K is achievable for (Ca + Sr)/Bi ratios between 1.4 and 1.65 while Tc- onset remains above 90K for Bi-2212 films. However, the best superconducting properties can be obtained for a (Ca + Sr)/Bi ratio which is quite close the nominal composition.
The use of a heavily Pb doped target is an effective way of Pb doping Bi-2223 thin films. A Bi-content of 1.410,sup>4
A/cm2 at 77K. The effect of the initial Pb content and annealing conditions on the formation of the Bi-2223 phase was investigated. It was found that high Pb content (0.92PbO4) formed below 835°C and its fraction increases with increasing sintering temperature up to 862°C, while the fraction of initial phases decreases. An annealing duration of 30 min. has provided highly oriented films with c-axis perpendicular to the substrate surface and sharp superconducting transition (<5K). Although Pb/Bi ratio is not critical in the range studied, when it is above 1.3 slow heating and cooling is necessary to prevent retention of excess Ca2PbO4 in the film after sintering. On LaAIO3 and SrTiO3 perovskite substrates, Tc is at least 5K lower than in the case of MgO. Nevertheless, LaAIO3 can provide good microstructure with a critical current density, of 5x104A/cm2 at 77K.
The direction and the range of variation of Tc in Bi-2223 films with oxidising process can be related to both the film composition (especially Bi and Pb content) and initial oxygen content. The variation range of Tc with oxidising is controlled by the Pb content. However, the maximum variation is around 4K at ambient pressure.
Radiation response measurements were carried out on films patterned into a 150μm wide, and 1 cm long meander-type structure using standard photolithography and wet chemical etching in EDTA. The results showed that the optical response using a continuous wave (cw) He-Ne laser is bolometric, while the microwave response using a 34.5 GHz Gunn diode microwave generator contains a non bolometric component.
Such polycrystalline Bi-based high Tc thin films may have interesting applications as sensitive microwave detectors, but they are not particularly good for microwave applications because of their high surface resistance, Rs, at microwave frequencies.
Mechanism of acid influx in the carotid body type I cell

Type I cells of the carotid body play a major role in acid chemoreception. Extracellular acidosis causes membrane depolarisation, Ca2+ influx and neurosecretion in the type I cell. A previous study has shown that pHi in the type I cell is very sensitive to changes of pHo, and intracellular acidification is a key step in the signalling pathway for acid chemoreception. This thesis investigates the mechanism responsible for mediating acid influx during isocapnic extracellular acidosis. Type I cells were enzymically isolated from carotid bodies obtained from neonatal rats. pHi was determined by microspectrofluorimetry, using pH-sensitive fluorescent dye carboxy-SNARF-1. My results show that there are two acid influx pathways. At resting pHi, Cl--HCO3- exchange accounts for over 70% of acid influx in response to extracellular acidosis. The remaining 30% of acid influx is mediated by an unidentified mechanism, which does not require either Cl- or HCO3-. I have also demonstrated that, the second pathway is an acid loading mechanism enhanced by a fall in pHo, rather than an existing background acid loading unmasked by the inhibition of acid extruder.
Although 200 µM DIDS inhibited Cl-0-free induced acid efflux mediated by reversed mode of Cl--HCO3- exchange as well as the acid influx induced by alkali load, it had no effect on the acid influx in response to acid challenge. The difference in DIDS effect to block acid influx is probably due to difference in Cl--HCO3- exchangers. I proposed that the Cl--HCO3- exchange system in the type I cell comprises two distinct exchanger populations. One of them is DIDS sensitive and activated by high pHi, while the other is DIDS insensitive and activated by low pHo.
The pHi and pHo sensitivity of both acid influx pathways have also been characterised. It is found that the unidentified HCO3--independent acid loading mechanism is activated by H0+ while virtually pHi-independent. In addition, the activity of Cl--HCO3- exchange system is very sensitive to pHi and pHo, with pKai and pKao values close to resting pHi and pHo. Thus any shift of pHi or pHo from the normal resting range will produce significant changes in exchange activity, leading to changes in acid flux into the cell. In this way, the Cl--HCO3- exchange system serves as a link for transducing acidic pH0 into parallel acidification in pHi in the type I cell.

Advisor: Vaughan-Jones, R
Buckler, K
Shining through the surface

This thesis has evolved from William Blake's phrase, "Imitation is Criticism" written in the margin of Sir Joshua Reynolds's Discourses on Art. As a concept central to the production and criticism of art, imitation has largely been explored in the philosophical context of aesthetics rather than in terms of its practical application in image-text studies of the Romantic period. It has also traditionally served as a marker for the period designation 'Romantic', which in image-text studies continues to be played out in terms of the transition from imitative to expressive modes of making and response.
Yet this notion of periodization has proven problematic in studying the response to 'false criticism' within what Wallace Stevens calls that 'corpus of remarks about painting'. These remarks reveal an important tension within imitation as a way of making something like something else, but also as a means of characterizing the relationships that underpin that resemblance. This tension not only occupies a central place in the concurrent development of art criticism and literary criticism in the period, but also offers a new foundation for the interdisciplinary study of image-text relationships in the period.
The thesis is divided into two parts, each guided by the important role that imitation plays in the fight against 'false criticism' with respect to the visual arts. The first part examines the tension within imitation from the standpoint of artists and connoisseurs who expressed concern about the excesses of description in asserting the need for a credible art criticism while at the same time realizing its inevitability. The second part examines the tension within imitation from the standpoint of the American artist Washington Allston and his friend Samuel Taylor Coleridge, both of whom used this tension to advantage in setting forth a lexicon and methodology that could account not only for the 'specific image' described, but also the geometrical and structural relationships that underpin that image.