VictorJuiz/thesis huggingface dataset:
Measurement of particulate emissions from gasoline direct injection engines
Keywords: DISI
GDI
DMS500
PM

Gasoline Direct Injection (GDI) engines have been considered to be the key enabler for reducing the CO2 emission from gasoline-powered vehicles. Compared to Port Fuel Injection (PFI) engines, GDI engines realize a higher compression ratio, a lower intake temperature and the absence of throttling which will deliver higher volumetric efficiency and lower fuel consumption. However, due to the reduced time for fuel atomization and the possibility of fuel impingement, GDI engines will inherently generate more Particulate Matter (PM) emissions than PFI engines. Previous research demonstrated that GDI engines typically emit one order of magnitude more PM than PFIs. Therefore, the number-based measurement of PM emissions from GDI engines is essential, for engine researchers and manufacturers to meet the number-based PM regulations in the near future.
This thesis undertakes to investigate: a) the effects of the after-treatment (Three-Way Catalyst) and various engine operational parameters, such as injection and ignition timing, injection strategy and valve timing on the PM emissions; b) the characteristics of GDI PM emissions using a range of gasoline/ethanol blends; c) The compositional information for GDI-generated PM emissions, i.e. the PM mass fractions in different volatility ranges. The first objective was achieved by using a Cambustion Ltd Differential Mobility Spectrometer 500 (DMS500) to simultaneously derive the PM size-resolved number concentrations and mass concentrations in the range of 5-1000 nm. The second objective was addressed by using the DMS500 together with other instruments such as a Photron high-speed camera, a Cambustion Ltd fast Flame Ionization Detector (FID). The third objective was realized by using Thermo-Gravimetric Analysis (TGA). These experiments are amongst the first of their kind and may well provide vehicle manufacturers and the fuel industry with useful data for PM control and abatement.
Data acquisition (DAQ) systems for two test engines, namely, a V8 GDI engine and a single-cylinder optical access engine, have been developed in LabVIEW to facilitate recording various experimental data at different sampling rates (1Hz to 300 kHz). The DAQ system in the single-cylinder engine is also capable for communicating with the engine controlling system to enable automatic data logging. A controlled automatic dilution system has been developed for taking filter samples in a way that is consistent with emissions legislation.
Mass transfer analysis of transdermal drug delivery using microneedles
Keywords: mass transfer
pharmacokinetic
modelling
microneedles
drug delivery

Microneedle is a promising technique for delivering high molecular weight drugs across skin. The microneedles can offer a number of benefits over other drug delivery methods. For example, the drugs only diffuse over a short distance before reaching the blood circulation which enhances the absorption of drugs by the tissue. However, the drug transport behaviour in skin is affected by a complex interplay of many parameters (e.g., microneedle geometries, permeability across skin, etc).
In this thesis, many aspects of the microneedle field were examined. A mathematical model for drug transport from microneedle systems into skin was developed. Issues such as microneedle penetration, surface area of the microneedle arrays, etc. were investigated. This work helped us to focus into optimizing the design of microneedles by developing an in-house algorithm to enhance the performance of transdermal drug delivery using microneedles. Following the development of this algorithm, the influence of skin thickness with its classification (i.e., age group, race, etc.) on drug permeability across skin was studied. Attention was then given to determine the effective permeability (Peff) and the effective skin thickness (Heff) for various solid microneedle models. The outcome of this research allowed us to study the influence of microneedle dimensions on the drug concentration in blood (Cb). Furthermore, the 'pattern' (shape) of the microneedles array (i.e., square or rectangular) and the 'distribution' (arrangement) of the microneedles inside an array (i.e., triangular or diamond) were investigated to identify the optimum microneedle models. Finally, the effect of skin metabolism on both the patch (without microneedles) and the microneedle arrays on drug intake were examined.
Peace as societal transformation: intergenerational power-struggles and the role of youth in post-conflict Sierra Leone
Keywords: social inequality
human rights
integration
intergenerational relationships
children and youth
social cleavages
social status
Africa
Rights (development)
social mobility
governance in Africa
conflict
history of Africa
local government

Intergenerational solidarity and reciprocity are fundamental building blocks of any society. At the same time, socio-generational groups constantly struggle for influence and authority. In Sub-Saharan Africa, disproportionately male, gerontocratic and patrimonial systems governing economic, social and political life lend a special explosiveness to the social cleavage of generation. This dissertation draws on the concept of the generational contract to explore whether Sierra Leone’s decade-long civil war (1991-2001) – labelled a ‘revolt of youth’ – catalysed changes in the power-asymmetries between age groups. Based on fieldwork conducted between 2007 and 2010, I argue that youth in post-war Sierra Leone question fundamental norms of intergenerational relations and challenge local governance structures demanding changes to the generational contract. Amidst a strong continuity of gerontocratic dominance and counter-strategies from elders, youth draw on organisational forms and a local rights discourse to create spaces for contestation and negotiation. These openings hold potential for long-term rearrangements of societal relations in the medium to long-term future.
Quantitative analysis of core-shell nanoparticle catalysts by scanning transmission electron microscopy
Keywords: energy dispersive X-ray analysis
high resolution
atomic resolution
high angle annular dark field
electron microscopy
catalyst
nanoparticles
specimen damage

This thesis concerns the application of aberration corrected scanning transmission electron microscopy (STEM) to the quantitative analysis of industrial Pd-Pt core-shell catalyst nanoparticles. High angle annular dark field imaging (HAADF), an incoherent imaging mode, is used to determine particle size distribution and particle morphology of various particle designs with differing amounts of Pt coverage. The limitations to imaging, discrete tomography and spectral analysis imposed by the sample’s sensitivity to the beam are also explored.
Since scattered intensity in HAADF is strongly dependent on both thickness and composition, determining the three dimensional structure of a particle and its bimetallic composition in each atomic column requires further analysis. A quantitative method was developed to interpret single images, obtained from commercially available microscopes, by analysis of the cross sections of HAADF scattering from individual atomic columns. This technique uses thorough detector calibrations and full dynamical simulations in order to allow comparison between experimentally measured cross section to simulated ones and is shown to be robust to many experimental parameters. Potential difficulties in its applications are discussed. The cross section approach is tested on model materials before applying it to the identification of column compositions of core-shell nanoparticles.
Energy dispersive X-ray analysis is then used to provide compositional sensitivity. The potential sources of error are discussed and steps towards optimisation of experimental parameters presented. Finally, a combination of HAADF cross section analysis and EDX spectrum imaging is used to investigate the core-shell nanoparticles and the results are correlated to findings regarding structure and catalyst activity from other techniques.
The results show that analysis by cross section combined with EDX spectrum mapping shows great promise in elucidating the atom-by-atom composition of individual columns in a core-shell nanoparticle. However, there is a clear need for further investigation to solve the thickness / composition dualism.
Essays on strategic voting
Keywords: tactical voting

In this thesis we extend the study of strategic voting to two frameworks that are novel to the literature. First, by analysing a four-party competition with purely instrumentally motivated voters (Part I); second, by focusing on a three-party competition where voters have instrumental and expressive motivations (Part II). We aim to explore an existing gap in the literature and, in particular, to investigate the possibility of a voting equilibrium with partial strategic voting and its stability. The three sub-models studied in Part I (including essay 1) and the model in Part II (including essays 2, 3 and 4) focus on the case of large electorates and include public uncertainty. This distinguishes them from Cox (1997), where no real uncertainty exists as the electorate gets large, and Myatt (2006), which includes both public and private information. Essays 2 and 3 present and explore the theoretical framework and implications for the model chosen for Part II and essay 4 applies it to the 1997 UK General Election. From essay 1 we obtain the result that in a single-ballot simple-plurality election there is a tendency towards the Duvergerian equilibrium in a four-party model. Also, an equilibrium with partial strategic voting is never stable. From essays 2 and 3 three main results arise: a Duvergerian equilibrium is never possible; a stable equilibrium always exists; and more information leads to less strategic voting – contrary to Myatt (2006). Both the impossibility of any Duvergerian equilibrium and the possibility of a stable interior equilibrium in multiple cases are central to our theory of voting that includes an expressiveness component. The simulations in essay 4 suggest that a very low level of expressiveness is needed to obtain a level of strategic voting compatible with the findings in Fisher (2004). The theory predicts the impossibility of some constituency results that are in fact frequently observed in British elections. Cox (1997), Making Votes Count. Cambridge, Cambridge University Press. Fisher (2004), ), Definition and Measurement of Tactical Voting: the Role of Rational Choice, British Journal of Political Science, 34(1), 152-66. Myatt (2006), On the Theory of Strategic Voting, Review of Economics Studies, Blackwell Publishing vol. 74(1), pages 255-281.
Use of high intensity focused ultrasound to destroy subcutaneous fat tissue
Keywords: subcutaneous fat tissue
high intensity focused ultrasound

Given the great promise of High Intensity Focused Ultrasound (HIFU) as a therapeutic modality, the aim of the present study is to develop and optimise a technique that uses externally applied focused ultrasound energy and remote, ultrasound-based treatment monitoring to destroy subcutaneous fat safely, effectively and non-invasively. Based on initial cavitation and temperature measurements performed ex vivo in excised porcine fat at four different frequencies (0.5, 1.1, 1.6 & 3.4MHz) over a range of pressure amplitudes and exposure durations, it was concluded that 0.5MHz is the optimal frequency for this application since it is capable of instigating inertial cavitation at relatively modest pressures while enhancing focal heat deposition. Histological assessment of tissue treated above the cavitation threshold at 0.5MHz both ex vivo and in vivo demonstrated damage to adipocytes and connective tissue. Furthermore, a good correlation was identified between the energy of broadband emissions detected by the passive cavitation detector (PCD) and the focal temperature rise at 0.5MHz during ex vivo experimentation, which could be exploited as a tool for non-invasive monitoring of successful treatment delivery. In addition, localisation of cavitation activity by means of passive cavitation detection was achieved and shown to provide a strong indicator of the location of induced histological damage. Based on the specific requirements identified during initial experimentation, an application-specific HIFU transducer, cavitation detector and real-time treatment monitoring software was developed and tested ex vivo. This treatment system was found capable of producing extensive damage to adipocytes and collagen confined to the subcutaneous fat layer at the desired treatment depth, which coincided with the location of cavitation activity as displayed by the real-time treatment monitoring software.
Some problems in abstract stochastic differential equations on Banach spaces
Keywords: Banach space
stochastic differential equations
stochastic integration
functional analysis

This thesis studies abstract stochastic differential equations on Banach spaces. The well-posedness of abstract stochastic differential equations on such spaces is a recent result of van Neerven, Veraar and Weis, based on the theory of stochastic integration of Banach space valued processes constructed by the same authors.
We study existence and uniqueness for solutions of stochastic differential equations with (possibly infinite) delay in their inputs on UMD Banach spaces. Such problems are also known as functional differential equations or delay differential equations. We show that the methods of van Neerven et al. extend to such problems if the initial history of the system lies in a space of a type introduced by Hale and Kato. The results are essentially of a fixed point type, both autonomous and non-autonomous cases are discussed and an example is given.
We also study some long time properties of solutions to these stochastic differential equations on general Banach spaces. We show the existence of solutions to stochastic problems with almost periodicity in a weak or distributional sense. Results are again given for both autonomous and non-autonomous cases and depend heavily on estimates for R-bounds of operator families developed by Veraar. An example is given for a second order differential operator on a domain in ℝd.
Finally we consider the existence of invariant measures for such problems. This extends recent work of van Gaans in Hilbert spaces to Banach spaces of type 2.
Structural and contextual hurdles to opposition party success in Namibia: the role of strategic dilemmas and political rhetoric
Keywords: Swapo
Namibia
ideology
elections

Ever since the third wave of democratisation swept the continent, Africa's opposition parties have been conspicuous by their poor performance. In explaining this weakness, the literature usually points to the disparity in resources and other incumbency benefits as well as narrow support bases of these parties. While these factors help explaining the poor performance of Namibia's opposition, they do not offer a full account. This thesis argues that strategic dilemmas arising from Swapo's electoral dominance, in interaction with a powerful historical narrative driven by the ruling party, make it harder for opposition parties to build sustainable, broad movements. Swapo's dominance means that voters think challengers are unviable and thus will not engage in strategic voting; it means that coalitions are unlikely because opposition party leaders see no point in putting differences aside; and it means that ruling party elites are unlikely to dissent. All of these tendencies are fortified by Swapo's powerful usage of political rhetoric. As the party that is credited with bringing about liberation from colonialism, Swapo draws upon a powerful well of legitimacy. The historical narrative it promotes reinforces these strategic dilemmas by painting Swapo as the only rightful representative of the Namibian people and labelling dissent as unpatriotic. The party also makes astute usage of rhetoric in the realm of ethnic politics, where it has forced all parties to adopt a form of diversity that is hard to manage with meagre resources. Thus, contrary to the stance of much of the literature on African politics, ideas matter.
Application of the Neutral Indel Model to genome sequences for diverse metazoans
Keywords: constraint
metazoan
evolution
Indel
genomics

The Neutral Indel Model is able to predict accurately the distribution of indel events in alignments of neutrally evolving genomic sequence. Here, I apply this model to a diverse range of metazoan species pairs, to a number of ends. First, I apply the Neutral Indel Model to alignments of genome sequences for species within the mammalian clade in order to estimate the quantities of functional DNA shared between species pairs. I demonstrate that as the evolutionary divergence between species pairs increases, estimates of functional sequence drop off dramatically. This pattern is not replicated in extensive simulations of genome sequence alignments, suggesting that functional (and mostly non-coding) sequence is turning over at a rapid rate. I also estimate that between 200 and 300 Mb (6.5-10%) of the human genome is under evolutionary constraint, a considerably higher quantity of sequence than has been estimated by previous whole genome analyses. Second, extending my analyses to consider more diverse metazoan species, I provide estimates for functional bases within organisms’ genomes that appear to mirror our conceptions of organismal complexity. Thirdly, I develop the Neutral Indel Model as a method for assessing genome sequence quality, by quantifying indel errors within alignments of closely related (ds < 0.1) species pairs. Applying this method to six primate genome sequence assemblies, I demonstrate that the frequency of indel error events per base varies up to six-fold. Further to this, I show that second generation sequencing technologies can be used to create high quality genome sequence assemblies and to ameliorate errors in pre-existing assemblies. Finally, I analyse patterns of indel mutations in primate transposable elements and show that indels are not randomly distributed within these sequences due to regularly spaced homo-nucleotide motifs.
The development of nitro-Mannich/hydroamination cascades for the synthesis of substituted N-heterocycles
Keywords: alkyne
chemistry
nitro-Mannich
hydroamination
pyrrolidine
allene
catalysis
cascade
pyrrole
organocatalysis
piperidine
synthesis
gold
organic
heterocycle
nitro
tetrahydropyridine
asymmetric

This thesis describes the development of nitro-Mannich/hydroamination cascade reactions for the synthesis of N-heterocycles, which are important motifs found in a variety of biologically active natural products and pharmaceuticals, such as atorvastatin (Lipitor®).
Chapter 2 outlines the development of an efficient synthesis of 2,5-disubstituted pyrroles using a nitro-Mannich/hydroamination cascade. Starting from easily prepared N-protected imines and nitroalkyne substrates, a compatible combination of KOtBu (10 mol%) and AuCl3 (5 mol%) was used to afford the desired pyrrole products, after an alkene isomerisation/HNO2 elimination reaction sequence.
Chapter 3 describes the extension of this methodology to the diastereo- and enantioselective synthesis of 1,2,3,4-tetrahydropyridine derivatives using a nitroalkyne substrate with an extended carbon chain. The sequential addition of a bifunctional Brønsted base/H-bond donor organocatalyst and a gold complex was found to facilitate the desired cascade reaction affording substituted 1,2,3,4-tetrahydropyridine products. We then established that highly substituted pyrrolidine compounds could be prepared by replacing the nitroalkyne substrate with a nitroallene substrate (Chapter 4). The combination of KOtBu (5 mol%) and a gold catalyst derived from Au(PPh3)Cl (10 mol%) and AgSbF6 (20 mol%) was found to give an efficient diastereoselective synthesis of pyrrolidine derivatives after an additional nitro group epimerisation step. In addition, the nitro-Mannich/hydroamination cascade using nitroallene substrates was developed into an enantioselective variant using the previously employed bifunctional Brønsted base/H-bond donor organocatalyst. This afforded enantioenriched pyrrolidine derivatives.
Of people, politics and profit: The political economy of Chinese industrial zone development in Nigeria
Keywords: foreign direct investment
emerging markets
African industrialisation

This project approaches ongoing debates over the impact of increased Chinese engagement in African countries through the lens of production and industrialisation. Emerging market FDI into Africa is growing rapidly, and an increasing proportion of this investment is into manufacturing and productive sectors. This trend is led by the commercial expansion of private Chinese manufacturing firms across the continent. The goal of this project is to examine the differentiated impacts on African industrialisation attempts of this phenomenon. It takes as its case study industrial zone development projects in Nigeria, namely, the two official economic and trade cooperation zones being developed as large-scale FDI projects by Chinese firms, with Chinese and Nigerian government support, in Lagos and Ogun states. Analytically, four dimensions of this process are identified for study: the home country context, the host country context, the zone structures and institutions, and the firms themselves. Special attention is paid to the interface between foreign actors and the particular political economy of Nigerian manufacturing, as well as the at times substantial gaps between policy and practice in terms of industrial planning, investment and production.
The thesis argues that SEZ projects in general, including the Chinese ETCZs, are industrial policy tools that operate on particular assumptions regarding the organisation of global production. As such, they incentivise the insertion of export-oriented firms into established global networks supplying international markets. However, a closer examination of industrial policy in China, the production environment in Nigeria and the behaviour of internationalising firms reveals that these assumptions are not always accurate. Thus, the SEZ institution as it is currently conceived in Nigeria is ill-suited to lend support to the trend towards Chinese relocation of producer firms, as well as to the reality of Nigerian production—both of which are predicated on domestic and regional markets as the primary driver of African industrialisation and productive sector growth.