VictorJuiz/thesis huggingface dataset:
A rate-pressure-dependent thermodynamically-consistent phase field model for the description of failure patterns in dynamic brittle fracture

The investigation of failure in brittle materials, subjected to dynamic transient loading conditions, represents one of the ongoing challenges in the mechanics community. Progresses on this front are required to support the design of engineering components which are employed in applications involving extreme operational regimes. To this purpose, this thesis is devoted to the development of a framework which provides the capabilities to model how crack patterns form and evolve in brittle materials and how they affect the quantitative description of failure.
The proposed model is developed within the context of diffusive interfaces which are at the basis of a new class of theories named phase field models. In this work, a set of additional features is proposed to expand their domain of applicability to the modelling of (i) rate and (ii) pressure dependent effects. The path towards the achievement of the first goal has been traced on the desire to account for micro-inertia effects associated with high rates of loading. Pressure dependency has been addressed by postulating a mode-of-failure transition law whose scaling depends upon the local material triaxiality. The governing equations have been derived within a thermodynamically-consistent framework supplemented by the employment of a micro-forces balance approach. The numerical implementation has been carried out within an updated lagrangian finite element scheme with explicit time integration. A series of benchmarks will be provided to appraise the model capabilities in predicting rate-pressure-dependent crack initiation and propagation. Results will be compared against experimental evidences which closely resemble the boundary value problems examined in this work. Concurrently, the design and optimization of a complimentary, improved, experimental characterization platform, based on the split Hopkinson pressure bar, will be presented as a mean for further validation and calibration.

Keywords: High inertia fracture
Dynamic Fracture
Brittle fracture
Strain-softnening
Explicit finite element
Pressure-dependent fracture
Phase field models
Semi-brittle materials
Finite element
Failure mode transition
Damage mechanics
Rate-dependent fracture
Micro-inertia
Impact
Advisor: Petrinic, N
Pre-clinical and clinical evaluation of the malaria vaccines RH5-VLP and PfSPZ vaccine

Despite progress through expanded use of bed nets and anti-malarial drugs, Plasmodium falciparum (Pf) malaria caused about 200 million cases and 500,000 deaths in 2015. An ideal vaccine would reduce the burden of disease and interrupt transmission. Despite decades of effort, there is no vaccine that can adequately address the global burden of malaria.
This thesis focuses on two potential weaknesses in the parasite life-cycle. First, I investigate two vaccination strategies aimed at improving the antibody response to RH5, an essential and conserved protein for erythrocyte invasion. Due to instability of the resultant recombinant vaccine constructs, these efforts have required re-engineering of the vaccine platform, which remains an ongoing effort.
Second, the immunogenicity and mechanism of protection of a live-attenuated whole sporozoite vaccine, PfSPZ Vaccine, was assessed. In a study that examined PfSPZ Vaccine at intravenous (IV) doses between 1.35 &tiles; 105 to 4.5 &tiles; 105 PfSPZ, I demonstrate that PfSPZ antibody responses correlated with durable sterile protection against controlled human malaria infection (CHMI). Surprisingly, the pre-vaccine frequency of Vγ9+Vδ2+ T cells, an innate T cell that recognizes conserved Plasmodium phosphoantigens, also correlated with durable sterile protection. Regarding the mechanism of protection, PfSPZ-specific antibodies as well as CD8 and CD4 T cells in the blood decreased substantially over time, yet sterile protection was maintained. In non-human primates, the CD8 T cell response in the liver at a memory time point was measured to be about 100-fold higher than found in the blood. Collectively, these data suggest that PfSPZ Vaccine confers durable protection in humans by long-lived, tissue-resident CD8 T cells.
These findings were extended with a study using 9.0 x 105 PfSPZ, wherein I demonstrate that T cell responses peaked immediately after the first vaccination with minimal T cell activation despite additional immunizations. This suggests that anti-PfSPZ immunity may be limiting the effectiveness of subsequent immunizations.
Finally, I examined the T cell response to PfSPZ attenuated by chloroquine (termed PfSPZ-CVac). T cell responses were substantially higher than achieved with comparable PfSPZ Vaccine doses. Additionally, a significantly higher proportion of PfSPZ-specific CD4 T cells were polyfunctional, simultaneously expressing IFN-γ, IL-2, and TNF-α, in subjects that were protected from CHMI.
In sum, these studies provide insight into the immunobiology of a protective immune response that may guide future malaria vaccine development efforts.

Keywords: Plasmodium
vaccine
clinical trial
T cell
malaria
Advisor: Draper, S
Hill, A
Towards stabilised cyclocarbons

This thesis describes synthetic efforts towards isolating cyclo[n]carbons. These elusive sp-hybridised allotropes of carbon have been synthetic targets for many years. Two modern stabilisation approaches are discussed that may provide the opportunity to finally prepare and study these molecules. Primarily, this thesis focuses on the stabilisation of sp-hybridised carbons by encapsulation with protective macrocycles. The concept of on-surface synthesis is also introduced and a method to prepare polyynes on surfaces using scanning probe microscopy is developed. These distinct approaches have simultaneously made significant progress in approaching cyclocarbons while enriching our understanding of polyynes.
Chapter 1 reviews the history of carbon-rich molecules, experimental and theoretical studies of cyclocarbons and the concept of stabilising carbon chains via encapsulation.
Chapter 2 explores the strategy of templating polyynes around a central core by preparing porphyrin-polyyne [3]- and [5]rotaxanes. There is also a photophysical investigation of excited state energy donation properties of polyynes.
Chapter 3 details the synthesis of cobalt-masked polyynes and their mild unmasking. This unmasking process yields pristine polyynes in unprecedented yields and offers significant promise for the use of this method in cyclocarbon catenane synthesis.
Chapter 4 summarises the synthesis of small macrocycles and dibromoolefin rotaxanes. These dibromoolefin rotaxanes have their protective silyl groups removed, yet remain interlocked.
Chapter 5 introduces scanning probe microscopy and developments in on-surface synthesis. Furthermore, we develop the controlled synthesis of polyynes from dibromoolefins, using the Fritsch-Buttenberg-Wiechell rearrangement by atomic manipulation.
Chapter 6 summarises the key results in this thesis and contains proposals for future work in this area.

Advisor: Anderson, H
Articulating the role of models in science education: Exploring the use of models in effective science pedagogies

The aim of the study is to articulate the role of models in Science education. Models have been used to represent phenomena in the natural world, to facilitate the understanding of abstract scientific concepts. How models make sense of the observed diversity of natural phenomena has been acknowledged in many science curricula and syllabi (OCR, 2016; NGSS, 2013). Visualizing models is important, as well as “understanding the natures of analogy and of metaphor, processes which are central to models and modelling” (Gilbert, 2004, p. 115).

Keywords: MLT
Science
MLT2017
Advisor: Childs, A
Can exposure to self-regulatory strategies help boys to improve attainment in Dual Award Science at GCSE level?

Self-regulation is one of the key attributes linked with the successful learner. Positive outcomes in every stage of schooling have been linked to attributes associated with self-regulated learning, however, promoting the skills, attributes or strategies required for accomplishing a student’s learning goals, or their desired outcomes, is much harder than simply relating these personal qualities with success.
Over the course of this research project I have attempted to summarise the key literature to establish the most important strands that are associated with the self-regulated learner. I then devised a yearlong intervention based upon this research for year 11 Science students approaching IGCSE examinations. The success of this was measured in two ways: results were compared with the previous cohort, who, through baseline data can be regarded comparable and broadly equivalent. The other measure utilised was the Motivated Strategies for Learning Questionnaire, which was distributed at the beginning and end of the intervention.
Through conducting this intervention exposing students to theory and practical ideas, their self-regulatory attributes improved slightly, I found a relationship between the achievement of top grades in Science with self-regulatory behaviours and attitudes. The high grades achieved meant a slight improvement on the IGCSE outcomes expected which, though not statistically significant, encourages me in implementing similar interventions on a broader scale in the future.

Keywords: MLT
MLT2017
Science
Advisor: Mcnicholl, J
Carmen heroum: Greek epic in Roman friezes

Roman wallpainting has been the subject of innumerable studies from the eighteenth century to the present day, but the epic-themed friezes of Late Republican and Early Imperial Italy have been comparatively neglected throughout this history of scholarship. This thesis therefore seeks to examine the three painted and stucco Iliad friezes from Pompeii, all found on the Via dell'Abbondanza, and the Odyssey frescoes from a house on the Esquiline in Rome, as four examples of a type which had a long history in the Graeco-Roman world, even if their survival in the archaeological record is scant.
The primary aim of the study is to understand each frieze in the knowledge of how they might have been regarded in antiquity, as elucidated in Pausanias' commentaries on Polygnotus' Iliupersis and Nekyia frescoes in Delphi, and to understand their extra-textual insertions and spelling discrepancies not as artistic errors but as reflections of the geographical and chronological contexts in which the friezes were displayed. Through detailed study of their iconography and epigraphy, alongside contemporary writers' discussion of the epic genre and its specific concerns for a Roman audience, this study aims to show that the most fruitful course of enquiry pertaining to the friezes lies not in an argument about whether they are entirely faithful to the Homeric epics or depart from them in puzzling ways, but in the observation that reliance on the text and free play on it go hand in hand as part of the epic reception-culture within which these paintings belong.

Keywords: Roman
Fresco
Iliad
Odyssey
Gladiators
Epic
Wallpainting
Advisor: Stewart, P
An investigation into the impact of flipped learning homework tasks on pupil motivation in science education

Homework is almost universally set and yet for some pupils it can be demotivating. In this study I aim to see whether the use of flipped learning (Bergman & Sams, 2012) homework tasks can serve to increase motivation. Over the course of a term, in two sets of year 12 biology, Kahn Academy videos were used to deliver 2 cycles of action research. Pupils were asked to watch videos and simultaneously make notes; in the following lesson they completed tasks to help consolidate their learning. Motivation was measured using the Science Motivation Questionnaire II (Glynn et al., 2011) and focus group interviews. The SMQII is designed to measure 5 aspects of motivation: intrinsic motivation; self-efficacy; self determination; grade motivation and career motivation.
The results of the study were notably different for the two sets. The SMQII results showed that flipped learning increased the motivation levels of the higher attaining set and decreased motivation in the other, lower ability, class. Interview data demonstrates the value of flipped learning in increasing self-efficacy and self-regulation in some pupils, but it is challenging and demotivating to others. It is evident from this study that for flipped learning to be effective, it is crucial that pupils are supported with appropriate resources. This evidence has helped to inform a review of homework in my secondary school and flipped learning will be employed in the biology department next year.

Keywords: MLT2017
Science
MLT
Advisor: Hillier, J
Groupwork and Feedback: Does the introduction of group average feedback impact on student opinion of groupwork in a mathematics class?

From a mathematics teacher perspective, group work is an invaluable learning tool which allows for discussion and sharing of ideas and methods with peers and friends. However students can appear not to share our affinity for group work, often complaining of unfair distribution of workload and competition within groups. To investigate the impact of individual accountability combined with group reward incentive (Boaler, 2008; Johnson and Johnson, 2008) on student opinion on group work within the mathematics classroom, an intervention was implemented in which students were placed in heterogeneous ability groups for a term with individual assessment results contributing to a group average result at the end of the term.
This intervention utilised the STAD (Slavin, 1983;2015) method of collaborative teaching and learning by utilising group average feedback to improve and encourage cooperative learning with groups in maths lessons. No group work teaching strategies such as Jigsaw or pre-coaching were utilised in the period in which students were working in these groups and students were not encouraged to learn or interact in specific ways within their groups to limit alternative influences on student opinion. The intervention was implemented with two classes and student opinion was evaluated using a sequence of questionnaires. Interviews were also utilised to further analyse and evaluate student opinion on group work. The findings suggested this intervention had an impact on student opinion but to ensure a positive impact additional teaching and learning strategies should also be undertaken.

Keywords: Mathematics
MLT2017
MLT
Advisor: Stylianides, G
The role of technology in the assessment of RE

A teacher has many aims, among them; they want a classroom where pupils are engaged in their learning and to have an easy and efficient way of measuring that learning. Aims such as these are also necessary for the teacher to have a safe and comfortable work environment, in which there is a reduction in workload.
There is no manual of how to achieve this and if there were, it would likely have moderate application outside of the school environment in which it was created. This research aims to select some of the key themes that arise in trying to achieve effective means of assessing pupils’ understanding in RE as well as reducing the impact of excessive workloads upon teachers. The research will take place within my own school and therefore the findings will be applicable to others who teach in my school. It is anticipated that the findings will also be applicable to those who teach other subjects and in other schools.

Keywords: MLT
Religious Education
MLT2017
Advisor: Robson, J
Examining the impact of positive feedback on student motivation

A significant body of educational research identifies intrinsic motivation as a significant factor in education with the capacity to improve outcomes for students. Motivation not only appears significant but also pliable. The use of praise has been explored to augment intrinsic motivation and a number of investigations suggest promise for process, outcome and effort praise. Many of these investigations, however, focus on short-term interventions and few aim to elicit the cognitive processes that underpin motivation and behavioural change. This work gives a full account of current motivational and praise literature, and seeks to investigate the implementation of praise types above within a long-term, classroom-based action research project. Praise interventions had a duration of one term and were administered to two year-9 classes (English and science) in an independent secondary school in the UK. A mixed method constructivist methodology is adopted comprising of the Motivated Student Learning Questionnaire (MSLQ) and a mixture of semi-structured and unstructured interviews. MSLQ responses failed to demonstrate significant change in motivation across any of the praise types. Interview discussions, however, highlight that students appear to have the capacity to be metacognitive regarding motivation and perceive significant value for process praise. The value attributed to process praise appears contingent on the perception of improved outcomes or progress.

Keywords: MLT2017
MLT
Advisor: Hillier, J
Doing the self: an ethnographic analysis of the quantified self

'Wearables' and 'self-quantifying technologies' are becoming ever more popular and normalised in society as a means of 'knowing' the self. How are these technologies implicated in this endeavour? Using insights from a four year multi-sited ethnography of the 'Quantified Self', I explore how the self is 'done' in the context of using technologies that purport to quantify the self in some way. Drawing on Science and Technology Studies (STS) sensibilities, I conduct a four- pronged investigation into 'self-making' by drawing upon, and expanding, existing theories of agency and performativity, number, data-visualisation, and enactment.
I find that self-quantifying technologies are productive in the doing of the self and are implicated in the process of making boundaries around that which comes to be known as the 'self' in a particular moment. The numbers and visualisations that result from practices of self-quantification enable a new way of 'seeing' the self, and provide a way of communicating this self with others. The self is thus not a pre-existing entity that simply requires these technologies as a means to 'know' it. Rather, the self is constantly being done with these technologies and within the surrounding practices of self-quantification.
In order to highlight the different parts of this process, I proffer the term 'entractment'. This term explains how these different elements come together to culminate in the production of a momentarily constant self in a particular context. It is a way of simultaneously encapsulating the processes of intra-action, extra-action and enactment with/in a community. In sum, it captures the conclusion that, in the context of self-quantification, we must understand the self as a collective enactment, achieved, at least in part, through the use of self-quantifying technologies that produce numerical data which facilitate visualisations that are imperative to the doing of the self.

Keywords: Quantified Self
Ethnography
Science and Technology Studies
Advisor: Woolgar, S
Lezaun, J
Characterisation of the high strain rate deformation behaviour of α-β titanium alloys at near-transus temperature

The aim of this thesis is to provide microstructural and mechanical characterisation of α-β titanium alloys exposed to a range of thermo-mechanical conditions, in particular under-going high rate deformation at elevated temperatures, representative of the Linear Friction Welding (LFW) manufacturing process. Three α-β titanium alloys provided by Rolls-Royce are studied: Ti-64 blade, disc and Ti-6246 disc. Ti-64 and Ti-6246 show complex deformation behaviour with strain, strain rate and temperature, especially near the transus temperature, where the low temperature α phase is transformed into the high temperature β phase. The microstructure and mechanical properties evolve in an interconnected fashion, and understanding this mutual influence is necessary to better predict the behaviour of these alloys.
Characterisation of the mechanical properties was performed through uniaxial compression tests at strain rates from 0.001 to 3000 s-1, using an Instron screw-driven machine at quasi-static rates, a servo-hydraulic machine at medium rates and a Split-Hopkinson Pressure Bar and a drop-weight tower at high strain rates. The tests were performed over a range of temperatures from room temperature to 1300 °C. The main focus was on high strain rate and high temperature tests, with the development of a gravity driven direct impact Hopkinson bar, referred as a drop-weight system, which is intended to evaluate the mechanical response of metals to high strain rate loading at temperatures up to c. 1300 °C. The design and principles of operation of the system are presented, along with calibration and validation data.
Preliminary tests were performed on stock Ti-64, heated at two rates: 1 and 20 °C s-1. The evolution of the mechanical properties was analysed, focussing on the strain rate, temperature and phases dependencies.
Characterisation of the microstructure was realised by performing interrupted compression tests, first at room temperature, three plastic strains, 4%, 10% and 20%, and two different strain rates, 0.001 and 2000 s-1; then at 4% plastic strain, a strain rate of 2000 s-1 and three elevated temperatures, 700, 900 and 1100 °C. A better understanding of the microstructure evolution with strain, strain rates and temperature, including the macrotexture and microtexture of the specimens, was obtained using Electron Backscatter Diffraction (EBSD) to characterise the texture of the undeformed and deformed materials.
The better understanding of the flow stress and microstructural evolution of both Ti-64 and its individual α and β phases with various strain rates and temperatures is intended to be used in the development of more accurate models representing the behaviour of these alloys. Predicting the microstructure evolution and then the mechanical properties of a material is essential to optimise the final mechanical properties of the alloys when welded by manufacturing processes such as the LFW process.

Keywords: Deformation texture
Titanium Alloys
EBSD
High strain rate deformation
Split-Hopkinson Pressure Bar
Advisor: Siviour, C