VictorJuiz/thesis huggingface dataset:
An analysis of contact stiffness and frictional receding contacts
Keywords: Contact stiffness
Linear elasticity
Receding contact

The tangential contact stiffness for ground Ti-6Al-4V surfaces is measured to linearly decrease with the application of tangential load. At the beginning of the application of tangential load, for ground surfaces, the ratio of the tangential contact stiffness to the normal contact stiffness is seen to be approximately half the Mindlin ratio. This is consistent with many other published experimental studies. Measurements of normal contact stiffness for ground surfaces conform to a model that posits a linear relationship between normal contact stiffness and normal load. An equivalent surface roughness parameter is defined for two surfaces in contact; and the normal contact stiffness for ground surfaces is observed to be inversely proportional to this parameter.
Single asperity models were constructed to simulate the effect of different frictional laws and plasticity on the tangential displacement of an asperity contact. Further, multi-asperity modelling showed the effect of different normal load distributions on the tangential behaviour of interfaces. In addition, normal contact stiffness was modelled for a grid of asperities taking into account asperity interactions.
A receding contact problem for which the required form of the distributed dislocations is bounded-bounded was solved. Then, a fundamental 2D frictional receding contact problem involving a homogeneous linear elastic infinite layer pressed by a line load onto a half-plane of the same material was analysed. This was done by the insertion of preformed distributed dislocations (or eigenstrains), which take into account the correct form of the separation of the interface at points away from the area of loading, along with corrective bounded-bounded distributions. The general method of solution was further refined and adapted to solve three other receding contact problems. The solutions demonstrated the robustness and applicability of this new procedure.
The supply of building materials to construction projects in Roman Oxfordshire: logistics, economics, and social significance
Keywords: Roman Building Materials
Petrography
Roman Trade
Classical Archaeology
Roman Britain
Scanning Electron Microscopy
Archaeological Science

Whilst Roman architecture has long stood as a discrete branch of classical studies, investigated for its artistic merit and cultural importance, the technical details of Roman construction have only recently started to receive considerable attention. This thesis contributes to a growing trend in Roman scholarship, that of the investigation of the processes, materials, and technologies behind the Roman built environment. The most prestigious buildings of the Empire often remain the focus of many of these studies, and so this thesis turns to explore the use of more everyday buildings and building materials, seeking a Romano-British vernacular, and investigating the processes of construction, building material production, and transport.
It is argued, through using theoretical calculations of building material quantities, that even for relatively minor constructions, considerations of building material supply must have represented highly significant economic and logistical investment. To comprehend fully the subject it is asserted that building materials should not be treated, as they often are, as disparate artefacts, divided by substance into stone, ceramic, mortar, metal, etc., but rather they should be considered as related fragments of a building. They require synthetic analysis, through which a far truer understanding of the incredible effort involved in construction in the ancient world can be gained.
The built environment of Roman Oxfordshire, and the Roman building material assemblage from Dorchester on Thames, are used as case studies. Primary analysis of building materials is carried out using an integrated analytical approach, combining thin section petrography with scanning electron microscopy and energy dispersive x-ray analysis. The outcomes of these analyses are interpreted against a background of archaeological and historical evidence for construction and material supply, in both the Roman and later periods, in the region and beyond.
Identity politics and discrimination law: addressing essentialism and assimilationism in disability and transgender discrimination law
Keywords: Disability
Transgender
Discrimination
Assimilation
Essentialism
Law
Identity Politics

Essentialism and assimilationism work hand in hand as well as in tension to oppress groups that are different from dominant norms in society. While integrating different groups into society, discrimination law may place undue assimilationist demands on these groups. Yet at the same time, identifying and addressing these assimilationist demands also risk essentializing these identities and ignoring the needs of individuals within these groups. This thesis aims at showing that disability discrimination law provides a framework that can perform anti-assimilationist and anti-essentialist functions, through elements such as non-essentialist grounds of discrimination, more relaxed uses of comparators and duties of reasonable accommodation. Furthermore, this framework can be applied to tackle similar concerns of other different groups in, for example, transgender discrimination law.
Molecular determinants of phleboviral cell entry
Keywords: glycoprotein
phlebovirus

Phleboviruses are emerging zoonotic pathogens which constitute a global threat to human and animal health. The mosquito-borne Rift Valley fever virus (RVFV) is a widespread problem across the African continent and causes regular deadly outbreaks in ruminants. The recently emerged severe fever with thrombocytopenia syndrome virus (SFTSV) is a serious human public health concern in China which has rapidly spread to Japan and Korea with fatality rates as high as 16-30%.
Phleboviral cell entry is mediated by two viral glycoproteins: the class II fusion protein Gc and the lesser known Gn. Initial cell attachment is glycan dependent and the penetration into the cell cytoplasm is mediated by the Gc fusion protein which catalyses viral and cell membrane merger. The entry mechanism is not well understood from a structural perspective which limits mechanistic insights. The purpose of this thesis is to further our understanding of the cell entry process by filling in the missing structural information on the phleboviral glycoprotein layer. To this end, an integrated structural approach using cryo-EM and X-ray crystallography was adopted.
The crystal structure of the Gn ectodomain is presented which reveals an unprecedented structural relationship with seemingly unrelated viruses. Single-particle cryo-EM and localized reconstruction reveal the glycoprotein layer of the RVFV and a pseudo-atomic model of the RVFV is presented. The assembly shows the shielding of the Gc fusion protein and suggests that the Gn functions as a fusion chaperone. The post-fusion crystal structure of the Gc protein from SFTSV further consolidates a mechanism of membrane fusion by class II fusion proteins. Finally, preliminary data on receptor binding and mechanism of antibody mediated neutralization are presented. The work presented herein provides a novel platform for studying and understanding entry and assembly of phleboviruses as well as the design of novel therapeutics.
Symbolic regulation: human rights provisions in preferential trade agreements
Keywords: statistical network analysis
non-trade issues
symbolic regulation
regulation theory
public interest groups

While the multilateral trading system views human and labour rights issues as outside of its remit, states increasingly incorporate regulation in these areas into their bilateral reciprocal preferential trade agreements, "HR-PTAs. This dissertation investigates the emergence of HR-PTAs, testing alternative explanations derived from conventional “public interest" and “private interest” theories of regulation against a new theory of "symbolic regulation." According to the public interest theory of regulation, regulation is motivated by benevolent legislators’ commitment to correcting market or social problems. The private interest theory of regulation instead views regulation as the result of private interest groups capturing the regulatory apparatus in order to regulate in their own self-interest. Unlike its counterparts, the symbolic theory of regulation suggests that regulation may also be created for the primary purpose of reassuring regulatory advocates that their demands have been heard, rather than to regulate a given issue area.
This dissertation argues that for the states behind them, HR-PTAs are primarily a symbolic form of regulation. Legislators create HR-PTAs to appease domestic human and labour rights organizations, while defending their trade interests through the non-enforcement of their provisions. Using longitudinal network analysis to analyse original data from 415 preferential trade agreements in force from 1989 to 2009, paired with case study evidence from the EU, US, and Canada, this dissertation finds support for the symbolic regulation explanation of HR-PTAs. It shows that a state’s commitment to HR-PTAs depends less on the public interest or the desires of private interest groups than on its need to accommodate human and labour rights advocates. Symbolic regulation however should not be dismissed. It sets precedents, creates policy space, facilitates softer forms of cooperation, and can fuel political accountability politics. When this occurs, states may use HR-PTAs or other forms of symbolic regulation to achieve their seeming purpose.
High risk feminism in Colombia: women's mobilisation in violent contexts
Keywords: Mobilisation
High Risk Feminism
Displacement
Colombia

Against all odds, in uncertain and violent times, Colombian women are mobilising for gender justice. They do so even when they face ongoing violence and personal threats from a variety of armed actors. The questions arise: how and why do women mobilise in contexts of high violence and insecurity? Despite a well-established tradition of studying women’s social movements in times of conflict, and of high risk collective action more generally, there is a lacuna when it comes to analysing feminism as a mobilisation strategy. My research uses the case studies of the Liga de las Mujeres Desplazadas (League of Displaced Women, LMD), and AFROMUPAZ (Afro-Colombian Women for Peace) to illustrate the utility of an original framework – High Risk Feminism – to explain how and why women chose to act collectively, despite the real and threatened dangers that this implies. The thesis further looks to a similar setting (an invaded neighbourhood in Riohacha, La Guajira) where displaced women do not mobilise, in order to strengthen the parameters of the HRF framework. In all, it posits that we will see a specifically feminist type of mobilisation emerge when a leader is able to form a charismatic bond with participants by framing participation as ‘worth it’ in a domain of losses, despite the risks this incurs.
The politics of literature in Chilean post-transition to democracy novels: portraits of society and the political status of women in the narrative of Diamela Eltit and Alberto Fuguet
Keywords: Chilean post-transition to democracy literature
Diamela Eltit
Literature and politics
Alberto Fuguet

This thesis explores the relationship between literature and politics through a study of novels published by Diamela Eltit (1949-) and Alberto Fuguet (1964-) in the Chilean post-transition to democracy period (i.e.: after the year 2000). It attempts to demonstrate that Chilean post-transition to democracy literature foregrounds the socio-cultural legacies inherited from the dictatorship (1973-1990), which have been to a great extent endorsed by the Chilean neoliberal transition to democracy. This thesis considers the more recent narrative fiction published by these authors as representative of Chilean post-transition to democracy literature, that is, a literature that shares a politico-historical legacy inherited from the Chilean dictatorship, and highlights a social imaginary permeated by the contemporary neoliberal politico-cultural project imposed by the military and to a great extent endorsed by the transition to democracy. In doing so, this work focuses on questions related to the portrayal of contemporary Chilean society and the political status of women.
Commitment in literature does not necessarily come from the author’s subjectivity or intention, but from his or her study of society and the way in which s/he presents it. Literary commitment, whether overt or not, remains fundamental in the case of contemporary Chilean writers, who have inherited a neoliberal socio-cultural context imposed by a dictatorship, and who may deploy strategies to either disseminate, perpetuate or resist such a cultural model, creating new ones. Therefore, the values to which literature commits can be traced in the case of both the overtly politically committed author and the apparently apolitical one. This methodology allows us to reveal the way in which Eltit and Fuguetʼs writing projects represent different but implicitly related views of Chilean society as well as two semi-canonical standpoints which are prominently representative of the twenty-first century Chilean literary sphere.
Topics in analytic and combinatorial number theory
Keywords: Metric poissonian property
Analytic Number Theory
Additive Combinatorics
Diophantine inequalities

In this thesis we consider three different issues of analytic number theory. Firstly, we investigate how residues modulo q may be expressed as products of small primes. In Chapter 1, we work in the regime in which these primes are less than q, and present some partial results towards an open conjecture of Erdős. In Chapter 2, we consider the kinder regime in which these primes are at most qC , for some constant C that is greater than 1. Here we reach an explicit version of Linnik's Theorem on the least prime in an arithmetic progression, saving that we replace 'prime' with 'product of exactly three primes'. The results of this chapter are joint with Prof. Olivier Ramaré.
The next two chapters concern equidistribution modulo 1, specifically the notion that an infinite set of integers is metric poissonian. This strong notion was introduced by Rudnick and Sarnak around twenty years ago, but more recently it has been linked with concepts from additive combinatorics. In Chapter 3 we study the primes in this context, and prove that the primes do not enjoy the metric poissonian property, a theorem which, in passing, improves upon a certain result of Bourgain. In Chapter 4 we continue the investigation further, adapting arguments of Schmidt to demonstrate that certain random sets of integers, which are nearly as dense as the primes, are metric poissonian after all.
The major work of this thesis concerns the study of diophantine inequalities. The use of techniques from Fourier analysis to count the number of solutions to such systems, in primes or in other arithmetic sets of interest, is well developed. Our innovation, following suggestions of Wooley and others, is to utilise the additive-combinatorial notion of Gowers norms. In Chapter 5 we adapt methods of Green and Tao to show that, even in an extremely general framework, Gowers norms control the number of solutions weighted by arbitrary bounded functions. We use this result to demonstrate cancellation of the Möbius function over certain irrational patterns.
Dynamical mass loss from unstable giants
Keywords: Mass loss
Hydrodynamics
Stars
Stellar evolution

Giant stars are believed to lose significant fractions of their total mass over their lifetimes, but the mechanisms responsible for this are ill-understood. One possible mechanism is dynamical mass loss – a hydrodynamical process in which matter is ejected from the stellar surface in ballistic outflows.
In this thesis, dynamical mass loss is studied in three stellar regimes: common-envelope objects, asymptotic giant branch stars, and red supergiants. Using hydrodynamical simulations performed with the stellar evolution code MESA, we examine the dynamical behaviour and stability of stars in each of these regimes.
We examine the dynamical properties of common-envelope objects during the slow spiral-in phase using a parameterised 1-dimensional model of orbital dissipatory heating.
We find that the envelope becomes unstable to high-amplitude dynamical pulsations that can lead to repeated mass-ejection events capable of removing the entire envelope and terminating the common-envelope phase. We estimate this process's \alpha efficiency value and suggest how these results might be employed in parameterised common-envelope models.
We employ coupled evolutionary and hydrodynamical simulations of AGB stars to study their dynamical properties as they traverse the TP-AGB and examine their dependence on basic stellar properties and on the thermal pulse cycle. We find that these models experience large amounts of dynamical mass loss, and we construct a parameterised model to estimate its strength. We find that this model is successful at locating the termination of the AGB.
We apply a similar approach to a study of RSGs, and find that dynamical mass loss also emerges in this regime. We estimate the conditions under which this occurs and discuss how this mechanism may resolve theoretical problems relating to the Humphreys-Davidson limit and the progenitors of SNe IIn.
We conclude that dynamical mass loss is likely to form a vital part of the mass-loss histories of cool giant stars.
Glucagon and glucose counterregulation: pancreatic α-cell function and dysfunction during hypoglycaemia
Keywords: Diabetes
Glucagon
Alpha Cells

The glucagon-secreting α-cell is vital for the maintenance of glucose homeostasis and prevention of hypoglycaemia. Despite its importance many aspects of α-cell physiology are disputed. Thus, in this thesis, I aimed to elucidate several features of α-cell function – exploring how autonomic signals are integrated by the cell and how diabetes leads to its dysfunction.
The autonomic response to hypoglycaemia results in increased acetylcholine and adrenaline in the islet vicinity, which stimulate glucagon secretion. The mechanisms underlying these effects were investigated using live [Ca2+]i imaging and patch-clamp electrophysiology. Adrenaline was found to target the α-cell via a β-adrenergic mechanism, inducing TPC2-mediated Ca2+ release from the (endo)lysosomal stores, which triggered calcium-induced calcium release from the endoplasmic reticulum (ER). Acetylcholine also induced ER Ca2+-release via muscarinic Gq signalling. However, a component of the effect resulted from activation of a nicotinic pathway that evoked P/Q-type Ca2+ channel influx.
The glucagon response to hypoglycaemia is lost in diabetes. To investigate the effect of hyperglycaemia on α-cell function at low glucose, the Fh1βKO type 2 diabetic mouse model was used. In these mice, prolonged hyperglycaemia led to blunted glucagon secretion at low glucose. Using live pH imaging, it was shown that this was caused by hyperglycaemia increasing flux through Na+ coupled glucose transporters (SGLTs), disrupting Na+-dependent acid extrusion and inducing cytoplasmic acidification. The resulting build-up of protons was speculated to compromise mitochondrial ATP production leading to the observed glucagon secretory defects. The effects of insulin-induced hypoglycaemia on δ-cell [Ca2+]i activity were also investigated. Increased SGLT2 transport and low [K+]o, features of insulin-induced hypoglycaemia, were both shown to increase [Ca2+]i activity in δ-cells, stimulating somatostatin secretion and consequently suppressing glucagon secretion. Together these data suggest that glucagon secretion at low glucose is lost due to the combined effects of hyperglycaemia-driven intrinsic dysfunction and insulin-induced somatostatin secretion.
Aspects of categorical physics: a category for modelling dependence relations and a generalised entropy functor
Keywords: Entropy
Diagrammatic reasoning
Strong maps (matroids)

Two applications of Category Theory are considered. The link between them is applications to Physics and more specifically to Entropy.
The first research chapter is broader in scope and not explicitly about Physics, although connections to Statistical Mechanics are made towards the end of the chapter. Matroids are abstract structures that describe dependence, and strong maps are certain structure-preserving functions between them with desirable properties. We examine properties of various categories of matroids and strong maps: we compute limits and colimits; we find free and cofree constructions of various subcategories; we examine factorisation structures, including a translation principle from geometric lattices; we find functors with convenient properties to/from vector spaces, multisets of vectors, geometric lattices, and graphs; we determine which widely used operations on matroids are functorial (these include deletion, contraction, series and parallel connection, and a simplification monad); lastly, we find a categorical characterisation of the greedy algorithm. In conclusion, this project determines which aspects of Matroid Theory are most and least conducive to categorical treatment.
The purpose of the second research chapter is to provide a categorical framework for generalising and unifying notions of Entropy in various settings, exploiting the fact that Entropy is a monotone subadditive function. A categorical characterisation of Entropy through a category of thermodynamical systems and adiabatic processes is found. A modelling perspective (adiabatic categories) that directly generalises an existing model is compared to an axiomatisation through topological and linear structures (topological weak semimodules), where the latter is based on a categorification of semimodules. Properties of each class of categories are examined; most notably a cancellation property of adiabatic categories generalising an existing result, and an adjunction between the categories of weak semimodules and symmetric monoidal categories. An adjunction between categories of adiabatic categories and topological weak semimodules is found. We examine in which cases each of these classes of categories constitutes a traced monoidal category. Lastly, examples of physical applications are provided. In conclusion, this project uncovers a way of, and makes progress towards, retrieving the statistical formulation of Entropy from simple axioms.
Soviet economic thought and economic policy in the 1940s. Influence on 1950s-1960s reforms.
Keywords: Soviet Union
N.A. Voznesensky
Planning
Command economy
Reform

The present thesis looks at the Soviet economy in the 1940s-1960s period. It specifically focuses on the influence of economic policy and thought developed in the late 1940s on the post-Stalinist era. The thesis’ aim is to prove that several key elements of 1950s-1960s economic reforms had already been conceptualised, proposed or implemented during the Stalinist period.
The pillars of this 1940s-1960s reforming continuity which the research deals with are khozraschet, economic levers (profit, value, market, prices, credit, bonuses), perspective planning, the balance of the national economy method, as well as the debates concerning the law of value and the repeated attempts at drawing up a General Plan and at drafting a new Party Programme.
The key figure this thesis focuses on is N.A. Voznesensky, top Soviet planner in 1939-1949. In the late 1930s he revived practices and methods discontinued after 1928, while under his aegis, policies and debates that later influenced post-Stalinist reforms were developed in the late 1940s.
The thesis relies on primary evidence gathered at four Russian state archives (RGAE, GARF, ARAN, RGASPI) and on research carried out at British, Russian, Italian and German libraries.