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Modelling the Evaporation of a Binary Droplet in a Well
Full text linkWhile the drying behaviour of sessile droplets has been extensively studied over
the last 25 years, the evaporation of droplets from wells (DiWs) has largely been
neglected, especially from a mathematical modelling standpoint. Understanding a
drying DiW is both important for industrial processes (such as inkjet printing and,
increasingly, the manufacture of organic displays) and an interesting problem in its
own right as a natural progression from sessile droplets, and we still do not have a
thorough theoretical description of their evaporation.
The main aim of this project was to build an understanding of pure and binary DiWs
under the lubrication approximation by constructing a simple mathematical model
for the evolution of their shape. We solved the resulting partial differential equations
for droplet height and composition profile numerically using the Method of Lines. In
the case of a pure droplet, we found that we could control the interface shape using a
single parameter (C) based on the capillary number; the more complex binary system
required two new parameters governing evaporation and surface tension differences.
Comparison to experimental data was improved with the inclusion of a dynamic
evaporative flux for each component that depended on the their volume fraction
distribution.
These simulations offer insight into the deposit that evaporating DiWs leave behind.
We have shown that the smaller C, the more likely the DiW will cause an undesirable
ring stain, but this is suppressed in binary droplets in which the more volatile
component has the lower surface tension
Dental anthropology investigations of behaviour and society in some historic Arctic/Sub-Arctic samples
Full text linkThe thesis is a dental anthropological study of Arctic/Sub-Arctic samples utilising oral environmental
health indicators (caries, calculus, periodontal disease), dental wear, craniofacial trauma (CFT),
paramasticatory dental activities (PMDA) and cultural identifiers to analyse labour and dietary divisions,
and how teeth were used as tools and cultural identifiers. The study was organised ecogeographically, as the
mostly historically collected remains meant temporal distinctions were largely impossible, bar being preEuropean contact. Contextualisation utilised ethnohistoric accounts, published bioarchaeological,
archaeological and clinical studies, and a PMDA recording method, developed here. A total of 1540
individuals were analysed from Siberia, the Aleutian Islands, Alaska, Canada, and Greenland. Arctic/SubArctic populations have been the focus of ethnohistoric, bioarchaeological, and clinical studies, but
misconceptions remain regarding homogeneity. Whilst many cultures extended across the ecogeographic
range of Arctic/Sub-Arctic populations, the divergent ecogeographies should result in distinct diet, labour,
PMDA, and cultural identification.
The oral environmental health indicators show overall, homogenously good oral health but were too
infrequent for dietary divisions assessment. Whilst the wear results were similarly non-distinct for the adults
for labour divisions, they illustrated the age PMDA began (5.5-10.5-years-old) when analysed in conjunction
with the CFT and PMDA results. The younger age (5.5-years-old) coincides with development of adult
levels of coordination and balance, and improved musculature control from changes in motor learning
abilities. The same type of PMDA was found to continue into adulthood in one sample (West Greenland).
Further distinct behaviours were found in another sample (Amaknak Island), as wear is absent in subadults,
but extensive wear is present in the adults.
The analysis also showed two distinct cultural identification configurations – wearing labrets and ablation
– with a demographic distribution and restricted to the Aleutian Islands. Ablation has been reported in
these populations, but not accepted by most researchers. The analysis found evidence that females and
males had different extraction methods and placements of ablation. In males, teeth were forcefully removed
from the socket, with the roots remaining, followed by alveolar bone resorption. The females experienced
a less traumatic extraction method, as roots remaining is absent. Evidence of wearing labrets inferior to the
labia inferior oris was found. The analysis also found an unreported labret placement, being superior to the
labia superior oris. The females and males have different patterns of wearing labrets, with females wearing
labrets laterally, and the males wearing one medially, both superior to the labia superior oris. The study
provides an immense amount of information on Arctic/Sub-Arctic samples, the homogenous oral health
environment, and the distinct PMDA and cultural identifiers
CAUSAL ORIGINS OF THE ‘RELIGIOUS MOVEMENT OF THE MIDDLE AGES': CLUNY, TIRON, AND THE NEW ORDERS, 910-1156
Full text linkAround the turn of the twelfth century, Western Europe underwent a profound ideological transformation. With the flourishing of new religious orders, heresies and sects, a new spirit captured the Latin West which glorified the asceticism of the early Church beyond all previous bounds and elevated the life of the poor itinerant preacher as its salvationary ideal. This Herbert Grundmann would call ‘the single religious movement of the Middle Ages’. Yet, for all its apparent import and power, history has thus far been unable to illuminate the fundamental causes of how this new ideology might have been generated, focussing instead on how new ideas may have been ‘transmitted’ into the Latin West from the near East. The aim of this thesis, therefore, is to remedy this gap in our knowledge by uncovering instead the epistemically ‘generative’ causal mechanisms of just such a ‘religious movement of the Middle Ages’, by advancing two interconnected hypotheses: that ‘ideas’ may be assembled by the a posteriori experience and observation of pre-mental ‘patterns of life’, and that the principal force responsible for the novel monastic ‘patterns of life’ in this period was a newly aggressive and expansionary Benedictine monasticism best typified by Cluny. In other words, that the origins of the new orders in ‘France’, and the ideology they espoused, is to be found in the systemic pressure applied by the growing influence of Cluny on the structure of the Church
The permeability of magma mush
Full text linkModels for the evolution of magma mush zones are of fundamental importance for understanding magma storage, differentiation in the crust, and melt extraction processes that prime eruptions. Mush mobilisation and melt segregation are predominant mechanisms that control mush evolution yet are to date still insufficiently understood and models for these are poorly constrained. These models are underpinned by calculations of the permeability of the evolving crystal frameworks in the mush, which controls the rate of melt movement relative to crystals. To date, no mush permeability model accounts for the shape of the crystals that form the crystal-framework in the mush. Herein, we assume that mush crystals are approximately cuboidal, and using that geometric approximation, we present new models for the permeability of mush in which crystal shape parameters are a key input. First, we present an extension of the Kozeny-Carman permeability law specifically for crystal packs at their maximum packing, for which the axis lengths of the crystals are the primary input. Second, we present a model for the evolution of magma mush permeability that is valid from maximum packing down to low melt fractions, ideal for simulating permeability as mush crystalises. In all cases we use a combination of numerical approaches to generate packs of cuboids for analysis, and experimental approaches to create digital 3D scans of anisotropic crystal shapes as an analogue for crystal mush. Using a combination of Avizo 3D image analysis, and a lattice-Boltzmann simulation technique, we constrain the permeability of both the numerical and experimental samples; these data then validate our models across a wide range of parameter space applicable to real magma mush. Furthermore, we propose and validate innovative solutions for permeability that can be found using only 2D data (for example, using a thin section scan), which is useful for common situations where full 3D information may not be available for analysis. In general, our results show that if we consider melt percolation in magma mush akin to fluid flow through porous media, the complexity and anisotropy are well represented by the specific surface area of the crystals. Knowledge of the crystal shape and size are essential variables in our proposed permeability model, unless the mush displays overgrowth textures at low melt fraction, in which case the effect of shape becomes less important. Our results have key implications for melt extraction timescales and cumulate textures as well as for crustal melt segregation processes and reactive flow on the scale of mush reservoirs
THREE ESSAYS ON CORPORATE SOCIAL RESPONSIBILITY
Full text linkThis thesis encompasses three empirical chapters, each focusing on a distinct aspect of corporate social responsibility (CSR) and examining both its drivers and outcomes at organizational and individual levels.
The first empirical chapter investigates the role of gender diversity in top management teams and its relationship with firms’ CSR engagement. Drawing on resource dependence theory, the primary findings indicate that female directors significantly enhance firm's CSR performance by contributing to board diversity. Furthermore, the results reveal that social trust bolsters the effectiveness of female directors.
The second empirical chapter explores the environmental issues and their driving factor, specifically institutional investors. The analysis demonstrates that institutional investors contribute to a reduction in greenhouse gas emissions among Chinese listed firms. The mechanism operates through the investors’ use of their voice in shareholder proposals.
The final empirical chapter delves into external experiences that influence CEOs' attitudes towards their firms' CSR profiles. The findings suggest that CEOs, motivated by a desire to enhance their reputation, tend to engage more in CSR activities following the receipt of an award. Concurrently, the easing of financial constraints facilitates these decisions. Ultimately, the results support the notion that CSR agency problems can lead to decisions made by awarded CEOs that adversely impact firm value
Development of Therapeutics for the Treatment of Leishmaniasis and Chagas Disease
Full text linkNeglected tropical diseases (NTDs) are an increasing global health challenge exacerbated by a shortfall in funding and new developments in the field. The social and economic repercussions of these diseases can be as overwhelming as their health effects. Current frontline treatments for leishmaniasis and chagas disease suffer from range of issues such as, high cost, prolonged treatments, severe side effects and drug resistance. Hence, there is a need for new drugs. A library of molecules with highly diverse chemical space was screened against Leishmania mexicana parasites. Four of the derivatives from Class One and Two, 40, 46, 60 and 64 showed EC50 values of less than 10 µM against L. mexicana intracellular amastigotes (3.12, 7.37, 4.86 and 3.27 µM respectively) and 9,10-phenanthrenedione (Class One) and 1,10-phenanthroline (Class Two) were identified as novel chemical scaffolds which could be developed as anti-leishmanial therapeutic agents. The repurposing ability of three FDA approved drugs; pyrithione (104), ciclopirox (105) and piroctone olamine (106) as a treatment for cutaneous leishmaniasis was investigated. Having EC50 values lower than 2 µM against L. mexicana intracellular amastigotes and selectivity index (SI) values greater than 10 proved that all three drugs have the potential to be repurposed. The promising anti-leishmanial activities reported for the four novel derivatives (116-119) synthesized from pyrithione (104) showed that the activity is not due to the metal chelation and modification of the N-oxide functionality of pyrithione (104) did not significantly change its biological activity. Furthermore, it was evident from in-gel fluorescence assays that pyrithione (104) and the novel derivatives (116-119) inhibit DUB16 enzyme, an enzyme essential for the viability of procyclic promastigotes, in L. mexicana promastigotes. However, DUB16 overexpression did not provide any resistance towards antileishmanial activity, meaning that these inhibitors may have other targets beyond this enzyme. Two fluorinated compound libraries in were screened against L. mexicana and Trypanosoma cruzi parasites. From these libraries 4-(benzenesulfonyl)-2,3,5,6-tetrafluoropyridine (198) was the only molecule found to be active against both the parasite species [EC50 (L. mexicana promastigotes); 1.33 µM, EC50 (L. mexicana axenic amastigotes); 0.433 µM, IC50 (T. cruzi epimastigotes); 1.55 µM, EC50 (T. cruzi infected stage); 0.05 µM]. Subsequently, the effect of 198 on programmed cell death in T. cruzi epimastigotes was investigated and results indicated that 198 triggers plasma membrane permeabilization and alters the T. cruzi epimastigotes mitochondrial function by collapsing mitochondrial potential, decreasing the intracellular Ca2+ concentration and disrupting the intracellular ATP levels. Additionally, it was discovered that 198 also arrest the G0 phase of cell cycle at higher concentrations. This suggests that 198 could be an interesting lead compound in Chagas disease drug discovery and development. A second-generation library derived from 198 was synthesised and their anti-parasitic activities were evaluated against L. mexicana axenic amastigotes. Finally, a label free MS-based proteomics analysis was performed to identify the target proteins of 230 in L. mexicana promastigotes and 19 proteins were identified as potential target proteins of 230
Image Diversification via Deep Learning based Generative Models
Full text linkMachine learning driven pattern recognition from imagery such as object detection has been prevalenting among society due to the high demand for autonomy and the recent remarkable advances in such technology. The machine learning technologies acquire the abstraction of the existing data and enable inference of the pattern of the future inputs. However, such technologies require a sheer amount of images as a training dataset which well covers the distribution of the future inputs in order to predict the proper patterns whereas it is impracticable to prepare enough variety of images in many cases.
To address this problem, this thesis pursues to discover the method to diversify image datasets for fully enabling the capability of machine learning driven applications.
Focusing on the plausible image synthesis ability of generative models, we investigate a number of approaches to expand the variety of the output images using image-to-image translation, mixup and diffusion models along with the technique to enable a computation and training dataset efficient diffusion approach. First, we propose the combined use of unpaired image-to-image translation and mixup for data augmentation on limited non-visible imagery. Second, we propose diffusion image-to-image translation that generates greater quality images than other previous adversarial training based translation methods. Third, we propose a patch-wise and discrete conditional training of diffusion method enabling the reduction of the computation and the robustness on small training datasets.
Subsequently, we discuss a remaining open challenge about evaluation and the direction of future work. Lastly, we make an overall conclusion after stating social impact of this research field
A systematic review and meta-analysis of interventions based on metacognition and self-regulation in school-aged mathematics
Full text linkMathematics is an important gatekeeper for educational and professional opportunities and a useful tool for discovery and expression. Given previous research and theory demonstrating potential for metacognitive and self-regulated learning (MC/SRL) interventions to support mathematics achievement with diverse learners, a systematic review was conducted to evaluate their effectiveness within the years of general education, with pupils of ages three to 18. Appropriately-designed studies that were reported in English between 2005 and 2019 were included. Following a systematic search, with double-reviewing and expert consultation for consistency, 1,761 bibliographic items were screened, resulting in 60 included studies. Qualitative aspects of the designs, contexts, participants, and intervention activities were synthesised narratively. Posttest-only and adjusted, random effects meta-analyses were performed using a single mathematics achievement measure from each study. The results indicate a generally positive effect from the included interventions (combined Cohen’s d=0.46, SE=0.08, 95% CI=0.30 to 0.60). This represents a somewhat more modest effect compared with previous reviews in this area, possibly due to a greater range of included reports. No risk of publication bias was identified, reflecting the breadth and diversity of included studies, but efforts to mitigate heterogeneity were only partially successful. Interventions using structured problem-solving with metacognitive prompts were more effective than those not using it, while dissertations reported lower effects than journal articles. No differences were found based on participant age or intervention dose. Primary studies used a variety of assessments and differed on reporting of interventions and quality-related factors, and there remained substantial heterogeneity in the meta-analysis. Implications of this review for educational theory, research, and practice are discussed, with emphasis on reporting studies fully, using broad-scope, comparable assessments, and investing in comprehensive metacognitive and self-regulated learning interventions that can support lasting change in teaching and learning
Accounting for Thermal Resorption of Bubbles in Magma in Experiments and Volcanic Eruptions
Full text linkThe growth of bubbles drives volcanic eruptions and plays a major role in determining eruption style. Therefore, understanding bubble growth processes is essential for forward modelling of volcanic eruptions and for interpretation of vesicular eruptive products. Decompression experiments at high temperature and pressure have been widely used to investigate bubble growth processes. However, most studies neglect bubble resorption, which occurs during the quench process as water solubility increases with decreasing temperature. Resorption may alter final textures, so accounting for this process is important for interpretation of experimental products.
This study quantifies the extent to which bubble resorption during cooling/quenching modifies the gas volume fraction () of the products of a series of decompression experiments. A numerical model is applied that captures bubble growth and resorption over arbitrary pressure-temperature-time (P-T-t) pathways to a published experimental dataset. The analysis proceeds in three stages: 1) Reconstruct the experimental P-T-t pathways and determine how evolves with time, in order to reconstruct pre-quench values. 2) Vary values of experimental parameters, such as bubble number density () and cooling rate to show when quench modification is most important. 3) Carry out a parametric sweep and advise on the best experimental conditions to use to avoid over-printing of experimental samples via resorption.
Resorption occurs in all experimental samples that are analysed. In one sample, the final is over a 50% decrease of the original bubble growth, consistent with values determined by a previous study. The analysis indicates that thermal resorption must be accounted for in the interpretation of experimental results and that greater resorption occurs when is high and cooling rate is low. In some instances, this leads to bubbles resorbing completely from a peak value as high as 0.10. The numerical model can be used as a tool to design experiments and minimise the effect of resorption, and it is anticipated that this will support more meaningful interpretation of vesicle textures and size distributions
Cosmology and Psychology in Stoicism: The Unifying Role of Mind in the Stoic System
Full text linkThe Stoics commit to a view of the universe as a unified living being endowed with a mind. But what is the explanatory value of this cosmological model? Generally speaking, most scholars believe Stoic cosmic psychology to work either as a metaphor for the unification produced by natural processes, or to be a consequence of the fact that mind is a primitive component of the Stoic system, given that one of the Stoic first principles is usually considered to be endowed with intelligence. In this thesis, I will argue against both views by claiming that the Stoics developed a highly sophisticated cosmic psychology in order to articulate an original theory of the unity of the cosmos. In doing so, I will first show how the Stoics introduce a new use of the notion of sympathy or co-affection (συμπάθεια) in order to produce an emergentist account of cosmic mental faculties. Then, I will then examine the unifying functions performed by the two main faculties of the cosmic mind: perception (αἴσθησις), which unifies the cosmos by endowing it with the ability of representing itself as a subject, and therefore, as an agent; and will (βούλησις), which unifies the cosmos by granting its activity a unified teleological orientation. I will thus make a strong claim regarding the relation between mental faculties and corporealism in the Stoics, showing how they are neither a metaphor for natural processes, but instead develop naturally from the principles on which Stoic philosophy is based, with the aim of articulating and unifying the complexity of the cosmos into a coherent whole
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