VictorJuiz/thesis huggingface dataset:
Being Young in Old Town: Youth Subjectivities and Associational Life in Bamenda

This study explores the ways in which young people in the neighbourhood of Old Town in Bamenda negotiate the predicament of blocked opportunities and ‘arrested adulthood’ occasioned by the decline in the nation-building project and prolonged socio-economic and moral crisis in Cameroon. I investigate how urban youth in Old Town construct their moral and socio-cultural worlds through involvement in associations. The main finding suggests that faced with growing uncertainty, young people in Bamenda are positioning themselves as important social actors by drawing on local cultural resources such as associations to construct their social worlds that aim to circumvent their exclusion and marginality. In this light, I analyse youth associations as central although not exclusive to negotiating young people’s predicament by focusing on a range of practices through which they seek respectability and claim social adult status. Drawing on the concepts of transition, subjectivities and personhood, I show that young people straddle the worlds of ‘youth’ and social adulthood, statuses that are not only cultural constructions but also the products of differential power relations and social positioning. I contend that the processes of positioning and the production of personhood are largely experienced through involvement in associational life. The study focuses on three associations, namely the Chosen Sisters, the United Sisters and the Ntambag Brothers Association (NBA). Organised on the basis of seniority and gender, I argue that these associations, while negotiating claims to adult status for their members, tend to challenge state-centric notions of citizenship as they simultaneously position themselves as moral actors upon whom society can count on for regeneration. Through a range of social projects, pursued on behalf of and sanctioned by the community, young people in Old Town reaffirm the centrality of interdependence and the situated understanding of social adulthood predicated on the redistribution of one’s success or achievement. This study points to the re-emergent role of associations in negotiating everyday life in the face of crisis. It is a significant contribution towards understanding voluntary and communal associations in general and young people’s modes of transitions into social adulthood.

Keywords: youth
citizenship
associational Life
morality
social adulthood
Advisor: Levin, Michael D.
Development of 8-Hydroxyquinoline Metal Based Organic Light-emitting Diodes

Because of its potential application for flat panel displays, solid-state lighting and 1.5 µm emitter for fiber optical communications, organic light-emitting diodes (OLEDs) have been intensively researched. One of the major problems with current OLED technology relates to inefficient electron injection at the cathode interface, which causes high driving voltage and poor device stability. Making a low resistance cathode contact for electron injection is critical to device performance. This work mainly focuses on cathode interface design and engineering. The Ohmic contact using a structure of C60/LiF/Al has been developed in electron only devices. It is found that application of the C60/LiF/Al contact to Alq based OLEDs leads to a dramatic reduction in driving voltages, a significant improvement in power efficiency, and a much slower aging process. A new cathode structure based on metal-organic-metal (MOM) tri-layer films has been developed. It is found that MOM cathodes reduce reflection by deconstructive optical interference from two metal films. The absolute reflectance from the MOM tri-layer films can be reduced to as low as 7% in the visible light spectrum. In actual working devices, the reflectance can be reduced from ~80% to ~ 20%. MOM cathodes provide a potential low-cost solution for high contrast full-color OLED displays. Low voltage Erq based OLEDs at 1.5 µm emission have been developed. The Erq/Ag cathode interface has been found to be efficient for electron injection. Dramatic improvement in driving voltage and power efficiency has been realized by implementing Bphen and C60 into Erq devices as an electron transport layer. Integration of Erq devices on Si wafers has also been demonstrated.

Keywords: Organic Light-Emitting Diodes
8-Hydroxyquinoline Metal
Advisor: Lu, Zhenghong
Autonomic Service Architecture for Next Generation Networks

Next generation networks will provide customers with a service mix placing variable demands for resources on the underlying infrastructure, motivating automated telecommunications services management approaches. This thesis proposes the Autonomic Service Architecture (ASA) for automated service delivery over next generation networks. First, we propose an architectural blueprint for ASA. We describe our view of the next generation network infrastructure, which will be application oriented. We elaborate on the layered design of ASA, the virtualization of resources, and the separation between manual and autonomic functions in the service delivery lifecycle. The autonomic functions are delivered by the interaction between Autonomic Resource Brokers (ARBs). The architecture of an ARB is then detailed, with a description of its different components and the message exchanges needed. Next, we discuss a Peer-to-Peer (P2P) naming and mobility management approach for next generation networks using ASA. This P2P approach will help ensure the scalability, robustness, and flexibility that ASA needs to ensure service delivery over next generation networks. The proposed P2P naming and mobility management infrastructure is then detailed, and its performance is evaluated. Finally, we suggest several autonomic resource management algorithms for ASA. The first algorithm is based on the Transportation Model, commonly used in the Operations Research community for cost minimization in delivering a commodity from sources to destinations, adapted to perform allocation of virtual resources. The second algorithm is based on the Assignment Model, commonly used in the Operations Research community for cost minimization in assigning several jobs to several workers, adapted to perform autonomic assignment of dedicated virtual resources. The third algorithm is based on Inventory Control, commonly used in the Operations Research community to analyze inventory systems, placing and receiving orders when needed for a given product, adapted to predict the demand on virtual resources. The fourth algorithm is based on Reinforcement Learning, commonly used in the Machine Learning community by agents to find a control policy that will maximize the observed rewards over their lifetime, adapted to adjust the prices of virtual resources.

Keywords: Management
Next Generation Networks
Advisor: Leon-Garcia, Alberto
Contrasts in Thermal Dffusion and Heat Accumulation Effects in the Fabrication of Waveguides in Glasses using Variable Repetition Rate Femtosecond Laser

A variable (0.2 to 5 MHz) repetition rate femtosecond laser was applied to delineate the role of thermal diffusion and heat accumulation effects in forming low-loss optical waveguides in borosilicate glass across a broad range of laser exposure conditions. For the first time, a transition from thermal diffusion-dominated transport at 200-kHz repetition rate to strong heat accumulation at 0.5 to 2 MHz was observed to drive significant variations in waveguide morphology, with rapidly increasing waveguide diameter that accurately followed a simple thermal diffusion model over all exposure variables tested. Amongst these strong thermal trends, a common exposure window of 200-mW average power and ~15-mm/s scan speed was discovered across the range of 200-kHz to 2-MHz repetition rates for minimizing insertion loss despite a 10-fold drop in laser pulse energy. Waveguide morphology and thermal modeling indicate that strong thermal diffusion effects at 200 kHz give way to a weak heat accumulation effect at ~1uJ pulse energy for generating low loss waveguides, while stronger heat accumulation effects above 1-MHz repetition rate offered overall superior guiding. The waveguides were shown to be thermally stable up to 800°C, showing promise for high temperature applications. Using a low numerical aperture (0.4) lens, the effect of spherical aberration was reduced, enabling similar low-loss waveguides over an unprecedented 520-um depth range, opening the door for multi-level, three-dimensional, optical integrated circuits. In contrast to borosilicate glass, waveguides written in pure fused silica under similar conditions showed only little evidence of heat accumulation, yielding morphology similar to waveguides fabricated with low repetition rate (1 kHz) Ti-Sapphire lasers. Despite the absence of heat accumulation in fused silica owing to its large bandgap and high melting point, optimization of the laser wavelength, power, repetition rate, polarization, pulse duration and writing speed resulted in uniform, high-index contrast waveguide structures with low insertion loss. Optimum laser exposure recipes for waveguide formation in borosilicate and fused silica glass were applied to fabricate optical devices such as wavelength-sensitive and insensitive directional couplers for passive optical networks, buried and surface microfluidic and waveguide networks for lab-on-a-chip functionality, and narrowband grating waveguides for sensing.

Keywords: Femtosecond laser
Waveguide
Advisor: Herman, Peter R.
Photophysics of Conjugated Polymers

Poly (para-phenylenevinylene) (PPV), and its derivatives such as poly [2-methoxy, 5-(2'-ethyl-hexoxy)-1,4-phenylene vinylene] (MEH-PPV), are typical conjugated polymers. In order to implement conjugated polymers into processable electronics technologies, we must first understand their complex photophysical properties as their efficiencies depend on the balance between exciton recombination and charge carrier formation. The inherent complexities of these materials arise from entanglement of the pi-electron system with disorder and nuclear motions of the polymer backbone. This disorder breaks the polymer chain into conformational subunits which can couple, giving rise to a set of delocalized states formed by Coulombic interactions between proximate subunits. Characteristics of PPVs include high quantum yields, non-mirror image absorption and fluorescence line shapes, and large apparent Stokes' shifts. These properties are discussed in the context of the relationships between polymer conformation, electronic structure, coupling, disorder and polymer photophysics. These important influences are often manifest in the dynamics of what happens after photoexcitation. In this work, we present 3-pulse photon echo peak shift (3PEPS) studies of conjugated polymers in both solution and film. To elucidate timescales characteristic of relaxation processes, we have simulated the 3PEPS data simultaneously with absorption and fluorescence, observing a rapid localization of the exciton in the initial ~ 20 fs. Additional contributions to the decay of the peakshift are discussed. We also present transient anisotropy data for PPV polymers and oligomers which is compared to dynamics simulation for isolated chains of PPVs. This work demonstrates the influence of microscopic structure on ultrafast dynamics. We show that relaxation between exciton states can lead to rapid depolarization of the anisotropy, even though the spatial extent of exciton migration may be small. Generally, the connection between conformation and electronic structure is a theme throughout this thesis.

Keywords: photophysics
conjugated polymers
Advisor: Scholes, Gregory D.
Copyright in the Real World: Making Archival Material Available on the Internet

The purpose of this study is to investigate the practices of Canadian repositories in making their archival holdings available on the Internet to see whether they are more or less restrictive than copyright law requires. The Internet provides an opportunity to make archival material more widely accessible; however, repositories’ copyright practices in making their holdings available online may affect the extent to which wider access to archival material is actually achieved. The study employed four different sources of evidence, i.e., the website content of 154 Canadian repositories whose websites feature archival material from the repository’s holdings; copyright policy and procedure documents of those repositories; 106 responses to a questionnaire sent to the staff of those repositories; and 22 interviews with repository staff members. In terms of selection for online access, the study found that the repositories studied prefer to select items that are perceived to incur little risk of copyright infringement (because the copyright has expired or because the repository owns the copyright), or items that require few or no resources to investigate copyright status or obtain copyright authorizations. Thus, with regard to selection, repositories were more restrictive than the law required, largely due to lack of resources. Although repositories have no legal or professional obligation to enforce others’ copyright interests, they nonetheless attempt to control further uses of their online holdings through the use of technical measures (e.g., low resolution images, watermarks, etc.) or non-technical measures (e.g., conditions placed on further uses), for reasons not necessarily related to copyright. Overall, the study found that repositories’ practices in making their holding available online were more restrictive than copyright law envisages. While this may be due to factors other than copyright, access to online documentary heritage may be limited as a result.

Keywords: Archival Materials--Digitization
Archivists--Canada
Copyright--Canada
Archives--Canada
Advisor: Duff, Wendy
Opposition, Politicisation and Simplification: Social and Psychological Mechanisms of Elite-led Mobilisation

Drawing on insights from social psychological literature on identity formation, and on social movement and contentious politics literature, this research focuses on elite strategies to gain from or survive a crisis. The research specifically looks at strategies to foster popular support and mobilisation. It explores the use of divisive and ethno-centric discourses and policies aimed at mobilising supporters in times of instability or crisis. More specifically, it studies why some elite mobilising appeals have traction. To do so, the research examines social and psychological mechanisms behind group solidarity. A heightened sense of group solidarity is what leads individuals to think in terms of the group, a necessary step for mobilisation. From there, they can be made to feel appeals for collective action are warranted. Three mechanisms in particular are discussed: opposition, politicisation and simplification. Opposing entails enhancing feelings of attachment by creating a sense of antagonistic relations with another group. Politicising consists in ascribing to group identities a political nature, more conducive to contentious relations. The final strategy is simplification. It amounts to simplifying interpretations of the situation and environment so as to make them more readily internalisable. This framework is applied to contemporary Rwanda and to the lead-up to the wars in Yugoslavia. In the Rwandese case, cultural and historical references were repeatedly used by ruling regimes to foster a Hutu uprising against the Tutsi population. This tactic eventually played a fundamental role in triggering the 1994 genocide. In the former Yugoslavia, Croatian and Serbian elites antagonised group relations by agitating nationalist rhetoric. Though this was a strategy to stay in power or gain support, it also led to the break-up of Yugoslavia and to wars in Slovenia, Croatia and Bosnia-Herzegovina.

Keywords: Mobilization
Conflict
Rwanda
Yugoslavia
Advisor: Homer-Dixon, Thomas
Perfuorocarboxylate Isomer Aanalysis as a Tool for Source Elucidation

Perfluorocarboxylates (PFCAs) are a class of anthropogenic compounds ubiquitously found in the environment. PFCAs and their precursors are largely manufactured by electrochemical fluorination (ECF) or telomerization. ECF products are mixtures of isomers with linear (70-80%) and branched perfluoroalkyl moiety. Telomerization does not produce isomer mixtures and is predominantly n-perfluorocarbons. This thesis examined the environmental fate and disposition of PFCAs from a relevant and novel perspective of industrial isomer signature. Potential influences of physical and biological properties of isomers on the environmental PFCA isomer pattern were investigated. Branched isomers were more water soluble than n-isomer, however, KOW did not indicate any appreciable differences among isomers. It is possible that the similarity in KOW is due to a balancing effect between elevated activity coefficients in both water and n-octanol. In fish and rats, the major branched isomers of ECF PFOA were eliminated faster than n-isomer. In comparison, PFOS isomer pharmacokinetics were indistinguishable. These findings highlight the need to understand underlying mechanisms mediating PFCA and PFOS isomer pharmacokinetics which may constrain extrapolation from animal-based models to humans. Environmental monitoring revealed PFCA isomers in both abiotic and biotic environment, in temperate regions and remote Arctic. Branched PFOA isomers were consistent with ECF production. In temperate regions, industrially produced ECF PFOA was expected to be a major source of these isomers, given its legacy and volume of production. In the Arctic, PFOA isomers consistent with an ECF signature were attributed to ECF perfluorooctylsulfonamides which likely undergo long range atmospheric transport and atmospheric reactions. The major difference in ECF signature between remote and temperate regions is the presence of ECF PFNA isomers compared to their absence in the Arctic. ECF PFNA is an impurity in ECF PFOA, comprising 0.2%. Input from a linear source, such as fluorotelomer compounds, was also suggestive as both PFOA and PFNA were >95% linear, much more than in technical ECF. Furthermore, longer chain ECF impurities do not account for the PFNA, PFDA, PFUnA, etc. in the Arctic.

Keywords: perfluorocarboxylate
isomers
Advisor: Mabury, Scott A.
The Use of Stereoscopic Cues in the Perception of Noise Masked Images of Natural Objects

When seen through a stereoscope, a Gabor pattern (a Gaussian enveloped sinusoid) that is masked by visual noise is more readily detectable when it appears in front of or behind the noise than when it is embedded in the noise itself. The enhanced visibility brought about by stereo cues is referred to as binocular unmasking. In this work, we investigated whether binocular unmasking may also occur with visual objects more complex than simple Gabor patterns, and with tasks more demanding than detection. Specifically, we examined the effects of binocular unmasking in the detection, categorization, and identification of noise masked images of natural objects. We observed the occurrence of binocular unmasking in all three tasks. However, the size of this effect was greater for detection performance than for categorization or identification performance; the latter two benefited to the same extent by the availability of stereoscopic cues. We argue that these results suggest that low level stereoscopic depth cues may play a helpful role, not only in simple detection tasks with psychophysical stimuli, but also in the perception of complex stimuli depicting natural objects.

Keywords: Binocular summation
Stereopsis
Stereoscopic vision
Visual recognition
Detection
Categorization
Identification
Advisor: Moraglia, Giampaolo
Schneider, Bruce A.
Stimulus-responsive Microgels: Design, Properties and Applications

Materials science today is a multidisciplinary effort comprising an accelerated convergence of diverse fields spanning the physical, applied, and engineering sciences. This diversity promises to deliver the next generation of advanced functional materials for a wide range of specific applications. In particular, the past decade has seen a growing interest in the development of nanoscale materials for sophisticated technologies. Aqueous colloidal microgels have emerged as a promising class of soft materials for multiple biotechnology applications. The amalgamation of physical, chemical and mechanical properties of microgels with optical properties of nanostructures in hybrid composite particles further enhances the capabilities of these materials. This work covers the general areas of responsive polymer microgels and their composites, and encompasses methods of fabricating microgel-based drug delivery systems for controlled and targeted therapeutic applications. The first part of this thesis is devoted to acquainting the reader with the fundamental aspects of the synthesis, functionalization and characteristic properties of stimulus-responsive microgels constructed from poly(N-isopropylacrylamide) (poly(NIPAm)) and other functional comonomers. In particular, the role of electrostatics on the swelling-deswelling transitions of polyampholyte microgels upon exposure to a range of environmental stimuli including pH, temperature, and salt concentration are discussed. The templated synthesis of bimetallic gold and silver nanoparticles in zwitterionic microgels is also described. The latter part of this thesis focuses on the rational development of microgel-based drug delivery systems for controlled and targeted drug release. Specifically, the development of a biofunctionalized, pH-responsive drug delivery system (DDS) is illustrated, and shown to effectively suppress cancer cells when loaded with an anticancer agent. In another chapter, the design of tailored hybrid particles that combine the thermal response of microgels with the light-sensitive properties of gold nanorods to create a DDS for photothermally-induced drug release is discussed. The photothermally-triggered volume transitions of hybrid microgels under physiological conditions are reported, and their suitability for the said application evaluated. In another component of this work, it is explicitly shown that electrostatic interactions were not needed to deposit gold nanorods on poly(NIPAm)-derived particles, thereby eliminating the need for incorporation of charged functional groups in the microgels that are otherwise responsible for large, undesirable shifts and broadening of the phase transition.

Keywords: microgels
drug delivery
nanotechnology
biomedical engineering
stimulus-responsive
gold nanorods
polymers
materials chemistry
polyampholyte
nanoparticles
Advisor: Kumacheva, Eugenia