VictorJuiz/thesis huggingface dataset:
Flow and combustion in direct injection spark ignition engines
Keywords: Laser Diagnostics
Internal combustion engines
Combustion

The goal of producing more efficient internal combustion engines has led to the use of more advanced technologies and operating strategies. As a result, Computational Fluid Dynamics (CFD) is now a standard tool that is used to optimise the design of new combustion systems. Validation of these numerical simulations is essential, especially for the prediction of in- cylinder flow, which is known to have a profound effect on mixture preparation and combustion. Therefore, high quality, in-cylinder flow measurements are required to aid the validation process and the design of new combustion systems.
This work outlines the development of an optical engine test facility and the installation of a high-speed Particle Image Velocimetry (PIV) system that provides in-cylinder flow measurements with high spatial and temporal resolution over a large range of crank angles. The system is capable of producing measurements at a maximum rate of 3.7 kHz at full resolution and a total of 6000 frame pairs in a single experiment. Additional improvements to the system for specific application to IC engines have been outlined, including the use of variable inter-frame delay and methods of scatter minimisation.
To aid the validation of CFD simulations, metrics known as the Weighted Relevance Index (WRI) and the Weighted Magnitude Index (WMI), have been developed to quantify differences between flow fields in terms of both alignment and magnitude. These have been combined to produce a third metric, the Combined Magnitude and Relevance Index (CMRI), that produces a single value that rates the similarity of two flow fields. The application of these metrics has been demonstrated by investigating the differences between velocity measurements and CFD RANS simulations in the central tumble plane for three test conditions. The metrics were able to determine regions of the flow field that were significantly different between simulation and experiment, which would not be highlighted by conventional metrics.
Flow field measurements were also made during the induction and compression strokes of firing cycles to investigate the effect of in-cylinder flow structures on cycle-by-cycle variations in combustion. The cycles were separated into subsets conditioned on burn rate, as indicated by in-cylinder pressure measurements. The WRI and WMI were then used to compare the conditionally averaged flow fields of fast and slow burning cycles. From this analysis, it was possible to determine regions of the flow that have a significant effect on the rate of combustion. Simultaneous combustion imaging showed that the flames for slow burning cycles tended to grow asymmetrically towards the exhaust valves. In contrast, the flames of fast burning cycles were convected away from the spark plug and grew rapidly in all directions.
Teens, screens and well-being: an improved approach
Keywords: Specification Curve Analysis
Open Science
Adolescents
Digital Technology
Well-Being
Social Media

Concerns about emergent technologies form a continuous cycle: they appear when a new technology surpasses a certain popularity threshold and stop once a newer technology prompts the cycle to restart. Currently, society is concerned about teenage digital technology and social media use, which is feared to negatively impact well-being. While there has been a flurry of research in the area, remarkably little consensus has been reached. I argue in this thesis that such a lack of consensus stems from a lack of methodological rigour. Using innovations put forth by psychology’s recent credibility revolution, I devise an improved methodological framework for the study of emergent technologies. I then apply it to investigate digital technology and social media use’s association with decreased adolescent well-being, using large-scale secondary datasets from the United Kingdom, Ireland and the United States. My first study implements a methodological approach called Specification Curve Analysis, which tackles analytical flexibility by illustrating how diverse analytical approaches can produce a wide range of numerical outcomes. Furthermore, I develop a comparison specification method to put the size of the associations found into perspective. My second study focuses on diversifying measurement and implements an explicit exploratory and confirmatory hypothesis testing framework. Lastly, my third study utilises high-quality longitudinal data to highlight the bidirectional and individual nature of the effects of interest. All studies indicate that previous systematic reviews overestimated the negative link between digital technology use and well-being. It is however still unclear whether the small, complex and inherently multivariate relationship found in this thesis should engender widespread policy change.
Advanced gas turbine cooling: double-wall turbine cooling technologies in turbine NGV/blade applications
Keywords: Heat Exchangers
Heat Transfer
Turbine Cooling
Gas Turbines
Turbomachinery
Aerodynamics

The drive to increase the thermal efficiency and specific power output of the gas turbine results in increasing turbine temperatures which necessitate active cooling of the turbine blades. High performance cooling systems are required which achieve the necessary blade life requirements whilst minimising coolant consumption. This thesis explores one potential turbine cooling system advancement termed the double-wall, effusion cooled system which is envisaged to find application in areas where high cooling performance is required.
Single wall effusion cooling performance is initially investigated given its importance in the double-wall system. An experimental investigation is performed and used to validate a computational model. A two-dimensional superposition method for predicting effusion cooling performance is presented and validated based upon the experimental and computational data.
The superposition method was used as part of a computationally light, decoupled conjugate method which was developed to predict the cooling performance of double-wall geometries. This decoupled method was used to assess several developed double-wall geometries. Those geometries which exhibited preferable cooling characteristic were manufactured for testing in a novel experimental facility, designed and commissioned as part of the thesis work. The facility incorporates several features to improve the quality of data obtained and matches several relevant non-dimensional parameters. The facility was used to obtain both overall effectiveness and film effectiveness results for five flat plate, double-wall geometries. This data was then used to infer the convective cooling performance of each geometry at varying coolant flow rates, with preferable cooling features identified. The results indicate the high cooling performance achieved in double-wall, effusion cooled geometries.
Two computational methods were used to replicate the experimental setup utilising boundary conditions obtained from the facility. The first was a fully conjugate solver, and the second was a modified form of the developed decoupled method. The results from both sets of simulations compared favourably with the experimental data. The decoupled conjugate method was particularly encouraging given the vast reduction in simulation time required when compared to the fully conjugate solver.
Thermomechanical analyses were performed to identify how various geometric features influence the stress field developed under thermal load, which has direct implication on blade lifespan. The work was successful in indicating certain double-wall configurations which could reduce the magnitude of the stresses.
A battlefield of memory: the Nakba and the Holocaust as exclusive victimhood narratives
Keywords: Israel

Situated in the post-Oslo era, this work constitutes a parallel analysis of the collective transmission of the foundational pasts in Israeli-Jewish and Palestinian society, respectively the Holocaust and the Nakba. Through the application of postmodern criticism to Maurice Halbwachs’ unitary understanding of group memory transmission, this thesis exposes the existence and perpetuation of exclusive and ethnocentric victimhood narratives that provide the theoretical foundations for an ensuing minimization of the out-group’s past. Divided into three sections, which correspond to the examined realms of memory transmission, a range of qualitative research methods are used to analyze the conveyed narrative across the established realms of collective memory transmission: official state education, commemorative acts and mass mediation. Beyond an analysis of the depiction of the primary history events in the societies’ curricula, mass media and commemorative institutes, semi-structured interviews with (former) memory agents and participant observation testify to the interplay between elites’ historical conceptions and the transmitted narrative.
While illustrating the universal plasticity of memory construction in coherence with contemporary political and societal needs, this work emphasizes the effects of the intractable Israeli-Palestinian conflict on the contemporary contextualization of the primary historical events and the ensuing subversion of the other’s past. Much like the original scenes of the watersheds and the principal actors, this thesis demonstrates that the exclusionary bases of Palestinian and Israeli victimhood narratives differ. The invocation of an exclusive Jewish Holocaust suffering thus is not unique to Israeli society; nevertheless, a consistent framing of a particularistic Zionist Holocaust victimhood narrative in the context of the Middle East conflict has stymied acknowledgement of the Palestinian catastrophe, deemed an inherent challenge to the ongoing redemptive nature of the Israeli state. An exclusive Palestinian victimhood narrative, conversely, has materialized in direct response to the opponent’s foundational memory. Rather than solely underlining an understanding of Israeli-Jewish political usage of the Holocaust, this thesis reveals that the retaliatory nature that characterizes the exclusive Palestinian narrative derives from its application as an interpretative framework –– an ‘ongoing Nakba’ –– which sheds light on the Palestinians’ marginalization and, consequently, demands a screening out of any past suffering of those held responsible.
Predictive sensing for field robotics
Keywords: autonomy
machine learning
robotics

The global autonomous robot market is expected to be worth more than eleven billion US dollars by 2024, with a need - across industries - for autonomous robots able to operate safely in complex and dynamic real-world environments. In this thesis, we argue that this will require developing robots able to develop situational awareness by constructing a higher level understanding of the world beyond the instantaneous and limited data provided by their sensors. We suggest this can be achieved by enabling robots to learn directly from their environment to predict the future evolution of the world and performance of their systems.
Robust mobile autonomy is developed around the three pillars of navigation, perception, and planning. For an agent to effectively plan a route through its environment, it needs to know where it is in its environment and what is going on around it. To do so, it is equipped with localisation and perception systems which can interpret incoming data from onboard sensors. Localisation systems typically provide instantaneous information with regards to whether an agent is localised or lost. Perception systems typically tracks objects in the environment using multi-stage pipelines which operate independently, require much hand-engineering, and show little robustness to natural occlusions. These low-level interpretations of incoming data often contribute to poor situational awareness and make it difficult to plan ahead with far-sightedness.
In this thesis we address both shortcomings and propose data-driven approaches to increase situational awareness for a localisation and perception system operating in the field. In the area of navigation, we propose a novel framework for predicting ahead of time how well a robot will be able to localise in a given environment given an appearance model of the scene. In the area of perception, we extend an end-to-end deep-learning framework for predicting near-future scene occupancy beyond natural occlusions, to operate in the real world, from a moving platform, and taking into consideration the scene context.
In doing so, we contribute to developing greater situational awareness for robotic systems operating in real world environments. We argue that robotic systems can make greater sense of what their are perceiving by moving away from instant sensing to predictive sensing.
Engineering quantum states of fermionic many-body systems
Keywords: Floquet theory
t-J model
Tensor networks
Hubbard model

Controlling and stabilising collective phases of many-body quantum systems is a problem of deep fundamental and technological interest. In this thesis, we perform a theoretical investigation on how useful quantum phases may be engineered in strongly correlated fermionic lattice systems, especially through periodic driving.
We first compute the phase diagram of the one-dimensional t–J model with the addition of non-standard pair hopping terms. We show that at dilute fillings these terms enhance superconductivity while, counter- intuitively, suppressing it at large fillings. We argue that this is due to dynamical constraints originating from the fact that local pairs cannot overlap. We conjecture that these constraints may play a more significant role in the physics of two-dimensional systems where the t–J model is studied as a candidate model of high-Tc superconductivity. We begin to investigate these dynamical constraints on a ladder geometry.
We then study the fermionic Hubbard model under periodic driving. We show that the driving induces a strong and robust singlet-pairing effect consistent with a superconducting state. This could provide a new mechanism for light-induced superconductivity in some classes of strongly cor- related materials. We show using Floquet theory that the dynamics of the driven Hubbard model are described precisely by the t–J model studied in the previous section. As the driven Hubbard model is also implementable with ultracold fermions in an optical lattice, our results could lead to their use as a quantum simulator for a broad class of candidate models for high-Tc superconductivity.
A critical survey of the Qur’ānic qul verses and their literary function in selected polemical exchanges
Keywords: Qur’an
Qul
Prophet
Islam

For what is often described as ‘the most common command in the Qur’ān’, the literary function of the word qul (meaning ‘Say!’, in the second person singular imperative form) still remains unclear and continues to pose ‘one of the most vexed questions of Qur’ānic rhetoric’. According to the standard concordance to the Qur’ān, the word qul appears 332 times in fifty-seven of its 114 sūras. Scholars have put forward a variety of classifications and interpretations for its Qur’ānic usage. This thesis explores existing interpretations of the word qul and I then analyse and classify all 332 qul statements according to their function in the respective passages in which they occur.
I posit that the vast majority (93%) of the qul statements are related to an antecedent in the Qur’ān. In many instances, these qul statements form one part in a complex matrix of responses to an antecedent, and the rhetorical effect of a qul statement in a given passage is determined by the antecedent, other responses and the syntagmatic interplay between them. This thesis demonstrates that the function of the word qul varies depending on the theme and the antecedent to which it is related. For example, quls in the form of rhetorical questions mostly draw attention to an aspect of God’s power, and they usually form a question and affirmation exchange; also nearly half of the quls in the Qur’ān respond to an audience question or statement beginning with an introductory verb derived from the Arabic letters q/w/l, such as, ‘They say (yaqūlūna), “…”’. Documenting the qul statements highlights the Qur’ān’s pervasive engagement with an audience, as well as its disputational character. Unlocking the function of qul statements reveals how Qur’ānic polemics work, and in turn how the Qur’ān engages with its audience. In the final chapter of this thesis, selected passages are examined in detail to demonstrate how the word qul in some selected passages strings together statements, objections, questions, and arguments.
Understanding the origins of strong multivalent cooperativity
Keywords: supramolecular chemistry
multivalency
host guest library
binding studies
entropy enthalpy compensation
chelate cooperativity
cooperativity

This thesis presents a combined experimental and computational evaluation of chelate cooperativity. The principal result from the thesis is that host-guest design cannot be limited to chemical intuition. By using a combination of theoretical approaches, we determined a procedure for a qualitative prediction of chelate cooperativity.
Chapter 1 briefly reviews the concepts of supramolecular chemistry and cooperativity, its different types and presents experimental methods used to quantify cooperativity.
In Chapter 2, host-guest are designed to probe different influences on chelate cooperativity. The synthesis of the studied host-guest library is presented.
In Chapter 3 we show whether cooperativity can be predicted based on simple molecular structures. Therefore, we determined binding constants for the selected systems and compared the chelate cooperativity strength qualitative and quantitative. Our conclusion is that even systems only exhibiting chelate cooperativity are too complex to base cooperativity prediction exclusively on molecular structure.
In Chapter 4, the cooperativity study of the presented host-guest systems is extended and contributions of entropy and enthalpy on chelate cooperativity are separated. The results have shown that the intramolecular process is driven by favourable entropy, but additional factors such as solvation lead to entropy-enthalpy compensation.
In Chapter 5, computational results on the prediction of effective molarities and cooperativity strength are presented. A benchmark compares different methods on the evaluation of supramolecular systems. The results have shown that theoretical methods allow a qualitative prediction of chelate cooperativity strength. A comparison of different solvation models revealed a procedure to reproduce experimental results.
Specialist environment courts: an interactional theory for legitimacy
Keywords: Public law
Adjudication
Legal theory
Environmental law

Specialist environment courts are, in the main, reflective of highly dynamic forms of adjudication, mixing judicial forms with powers more traditionally found in the executive. However, despite their novel legal nature the literature on specialist environment courts is predominantly promotional and it fails to address the challenges to legitimacy and governance engendered by these institutions. Nor does it evince a robust theory of environmental adjudication. These omissions not only impoverish the discourse but practice unsupported by theory is creating an unstable edifice. This thesis develops a new theoretical model capable of explaining and accommodating environmental adjudication. The theory suggests that normative legitimacy will be fostered if the adjudicatory body responds to, rather than ignores, the inherent nature of the problems it is charged with resolving. Further, to ‘respond’ appropriately necessitates an interactional process. In the context of environmental adjudication four factors are indivisible parts of the whole: identifying the inherent nature of environmental problems; acknowledging the commensurate challenges for law and dispute-resolution; developing legal principles, procedure and remedies that respond to those challenges; and acknowledging that particular adjudicative forms and functions can facilitate this process.
Social solidarity among Chinese Canadian evangelicals in short-term missions
Keywords: Sociology
Chinese Canadian
Religion
Social Solidarity
Short-term Missions
Evangelical

This thesis examines how Chinese-Canadian evangelicals (CCEs) maintain social solidarity through short-term missions (STMs) to China. STMs are pilgrimage-like service trips that entails an individual to travel to a distant place to engage in social service for one or two weeks. This research draws on theoretical insights from Randall Collins’ interaction ritual chains (IRC) theory to examine the intersections of ethnicity, religion, and emotions at the macro-, meso-, micro-, and situational levels. This study involved over 131 in-depth interviews with 48 STM participants, observations of four STMs in 2015, and a two-year ethnography of a sending church north of the Greater Toronto Area in 2015-16. My first empirical chapter takes a macro-level perspective to investigating the global missions phenomenon. My findings reveal that the religious discourses that motivate the collective actions of transnational Chinese fundamentalist organizations are unstable, and this unity based on a religious pan-Chinese ethnicity is challenged by linguistic, geographic, generational, and ideological fractures. In my second chapter analyzing the meso-level CCE congregations, I observed how they maintained their organizational focus by operating cyclically and how each congregation’s members actively participated to maintain the pursuit of their mission. In my third chapter, I focus on the micro-level motivations for CCEs to engage in STM action. I connect contemporary neuroscience to IRC theory’s conception of IR “chains,” and suggested the concept be revised to “entangled chains.” I discuss how acknowledging the emotional entanglement of various identities should drive the analytical discussion of the self in modernity. My final chapter examines how situations of putative spiritual conflicts allowed STMers to generate various collective-effervescence outcomes. This thesis contributes to the sociology of religion and emotions and our understanding of communities by uncovering how social solidarity is generated and sustained at multiple levels of social organization.