Developing etching of GaN material system is the key to device fabrications. In this thesis, we report on the fabrication of high throughput lift-off of InGaN/GaN based micro-membrane light emitting diode (LED) from sapphire substrate using UV-assisted photoelectroless chemical (PEsC) etching. Unlike existing bandgap selective etching based on unconventional sacrificial layer, the current hydrofluoric acid based wet etching process enables the selective etching of undoped GaN layer already incorporated in standard commercial LED structures, thus attaining the leverage on high performance device design, and facile wet process technology. The lift-off micro-membrane LED showed 16% alleviated quantum efficiency droop under 200 mA/cm2 current injection, demonstrating the advantage of LED epitaxy exfoliation from the lattice-mismatched sapphire substrate. The origin of the performance improvement was investigated based on non-destructive characterization methods. Photoluminescence (PL) characterization showed a 7nm peak emission wavelength shift in the micro-membrane LED compared to the GaN-on-Sapphire LED. The Raman spectroscopy measurements correlate well with the PL observation that a 0.86 GPa relaxed compressive biaxial strain was achieved after the lift-off process. The micro-membrane LED technology enables further heterogeneous integration for forming pixelated red, green, blue (RGB) display on flexible and transparent substrate. The development of discrete and membrane LEDs using nano-fiber paper as the current spreading layer was also explored for such integration.

The aerospace industry endeavours to improve modern aircraft capabilities in efficiency, endurance, and comfort. One means of achieving these goals is through new enhancements in aerodynamics. Increased wing aspect ratio is an example of further improving efficiency. However, this comes with new challenges including possibly adverse aero-elastic and aero-servo-elastic (ASE) phenomena. New computational methods and tools are emerging and there is a need for experimental data for validation. University of Victoria’s Centre for Aerospace Research (UVic CfAR) set out to design a 20kg ASE demonstrator using a remotely piloted aircraft (RPA). This aircraft was designed with the intent of exploring coupling between aero-elastic modes including coupling between the short period aerodynamic mode and the first out-of-plane elastic mode of the wing. This thesis discuses the implementation of instrumentation designed and integrated into the ASE RPA demonstrator to monitor the deformation of the elastic wing in-flight. A strain based measurement technique was selected for integration into the ASE aircraft. This choice was made for several reasons including its reliability regardless of outdoor lighting, relatively lightweight processing requirements for real time applications, and suitable sampling bandwidth. To compute the wing deformation from strain, a method, sometimes referred to as strain pattern analysis (SPA), utilizing linear combinations of reference modal shapes fit against the measured strain, was used. Although this method is not new, to the author’s knowledge, it is the first practical application to a reduced scale RPA demonstrator. The deformation measurement system was validated against a series of distributed static load tests on the ground. Distributed load cases along the wing demonstrated good out-of-plane measurement performance. A case where only load is applied near the root of the wing resulted in the largest error in part as the mode shapes generated are less suited to approximate the resulting shape. In general errors in out-of-plane displacement at the end of the flexible wing portion can be expected to be less than 5%. The displacement at the tip of the wing can be as great as 11% for the left wing whereas the right wing is 4.7%. This suggest an asymmetry between the left and right wings requiring specifically tuned FE models for each to achieve best results. Twist angles presented in tests were relatively small for accurate comparison against the reference measurement, which was relatively noisy. Generally, the deformation measurement by SPA technique followed the same twist behaviours as the reference. A twist case, unlikely to be seen in flight, provided some insight into twist measurement robustness. The work presented is merely a small step forward with many opportunities for further research. There is room for improvement of the FE model used to generate the mode shapes in the strain pattern analysis. Initial efforts focused on the flexible spar portion of the wing. With more work improvements could be achieved for the estimation of the rigid wing. Additionally, there was some asymmetry between each wing semi-span, and with some focus on the left wing its results could be improved to at least match that of the right wing. A real-time implementation was not completed and would be particularly interesting for use as feedback for flight control. Study of load alleviation techniques may benefit. Another topic of study is the combination of this method with other measurements, such as accelerometers, to provide improved performance state estimation through sensor fusion. / Graduate

Thesis (DPhil (Environmental Health))--Cape Peninsula University of Technology, 2016. / Informal caregivers play an important role in the well-being of dependent members in a household. The burdens of these caregivers are multiple and pervasive and may contribute to mental health epidemiology as a result of worry, grief, anxiety and stress. The literature review revealed that studies in caregiving and its various facets began from a pragmatically applied interest rather than from theoretical and intellectual curiosity. The majority of the research on caregiver burden involves meta-analysis of qualitative studies with little quantitative research. Also, many of these studies are concentrated on caregivers of chronically ill patients, such as those suffering from dementia, Alzheimer’s disease, and heart disease, without much attention to care burden resulting from caring for those who are not necessarily ill. Similar studies by other researchers did not consider the impact of the physical health of the care recipients or the environmental factors that are critical in the study of female caregiver burden in low-income settings. In addition, existing studies did not adequately evaluate the many potential factors that may vary and influence the lives of the caregivers, especially in a single, comprehensive model. This study attempted to provide a more complete picture of these relationships in low-income and culturally diverse settings. The study population consisted of black/African and coloured populations living in subsidised or low-cost housing settlements. In each of the two different cultural communities, 100 black/African and 100 coloured female caregivers were selected through a systematic random sampling procedure. In addition, data were also collected from caregivers in Tamale, Ghana to assess differences between the socio-demographic profiles of the caregivers in Cape Town, South Africa and Tamale, Ghana. The theoretical paradigm used in this study is the Stress Process Model by Pearlin et al., (1990). The study instrument assessed caregiver burden with both objective and subjective measures through the use of a fully structured questionnaire. The information that was collected according to the constructs of the Stress Process Model included personal and role strains and incorporated the physical health of the care recipients and environmental factors such as kitchen and toilet hygiene. Inclusion criteria for the respondents in both Cape Town and Tamale were the principal female caregivers who were present, willing, and able to give informed consent. The Statistical Package for Social Sciences (SPSS Version 22) was used for the analyses. The Chi-square test was used to assess the relationships between environmental health, the socio-demographics of the female caregivers and the health status of the care recipients. The hierarchical regression analysis in the form of a General Linear Model was used to model caregiving burden. iv The results showed that the majority of the female caregivers were in the age group 40 – 49 years and in both Cape Town and Tamale, a large proportion was in the low-income group. Also, the majority of the informal caregivers in the two samples were in care tasks as a full-time job, providing more than 40 hours of care per week. Regarding the length of time in caregiving, a large proportion of the caregivers in both Cape Town and Tamale had been in the care role for more than three years preceding the survey, and almost all the caregivers in the Cape Town sample (98.4%) did not use any form of caregiving programme to ameliorate the negative effects of caregiving. Further, the results showed statistically significant relationships between the socio-demographic characteristics of female caregivers (age, education, population group and income status) and the diarrhoea status of the care recipients. Also, a significant relationship was shown between environmental health variables of the home (kitchen hygiene and toilet hygiene) and the physical health of the care recipients. The major predictors of female caregiver burden in the samples were the physical health of the care recipients and access to social grants. On the basis of the analyses, it was recommended that the government should recognise the importance of the physical health of the care recipients and increase the amounts of social grants to the caregivers since this could improve the circumstances of both the caregivers and the care recipients. In addition, this could aid in improving the standard of living of caregivers in these households. Future research in similar settings should disaggregate the data to compare the burden of caring for caregivers of physically strong care recipients with physically ill care recipients.

Driving piles constitute a large portion of the high-capacity foundations used today. They transfer structural loads to deep bearing strata when adequate surficial soils are not available. The mechanisms required to install these piles generally consist of a hammer, hammer lead, a crane, and various support rigging. This study focused on lead sections, specifically, one which was manufactured by Berminghammer Foundation Equipment, Inc. The dimensions and strength of a lead section must be capable of supporting both the pile driving hammer and the longest anticipated pile for a given site. The strength of the section must be capable of withstanding hundreds of tons in compression and bending. If the lead is operated in a batter, (tilted forward, backward, or sideways) the weight of the hammer and pile causes much more bending than the vertical orientation. The cross-section details for these long steel sections vary from design to design but usually incorporate some form of bolt group, pins, and steel alignment dowels. This thesis focuses on the design, modeling, and testing of such a connection. The motivation of the study stems from a company-wide incentive to standardize the connections used to splice the Berminghammer C15-series lead section. In an effort to verify a proposed connection design, Berminghammer Foundation Engineering solicited the University of South Florida to test a full-sized lead section to failure, while monitoring the splice-connection performance.

School violence has gained attention in recent years with the rise of aggressive behavior in schools across the United States. With increased understanding of this problem, school district administrators might implement prevention strategies or assess current school violence policies and programs. Using the conceptual framework of general strain theory, a case study was conducted in an urban school district in the northeastern United States that was experiencing increased student violence. The purpose of this case study was to explore teachers' perceptions of school violence to increase the understanding of the problem at the study site. All certified teachers in the study district were invited to participate. Data were collected through in-depth interviews with 12 teachers in 9 elementary schools. After compiling, disassembling, reassembling, and coding the data, various themes emerged. The findings from the interviews revealed a need for district-wide consistency to address school violence, professional development to train staff on violence related issues and mandates, and a program to combat as well as prevent the existence of violence in the school climate. A recommendation is that the school district adopts the School Wide Positive Behavior Intervention Supports to provide a framework of consistent management of student behavior and professional development practices within a district-wide violence prevention program. The study contributes to positive social change by increasing the understanding of school violence at the study site and providing the recommended program designed to improve school climate, student learning, and social behavior through a tier leveled system designed to reach all levels of school violence.

A greenhouse experiment was conducted to determine the interactive effects of water salinity, volume of water applied at each irrigation, sodium adsorption ratio and rhizobial strain upon 15 plant growth parameters of Phaseolus vulgaris L. Four levels of water salinity (ECW 0.4, 3.0, 6.0, or 9.0 mmho/cm), three levels of water volume (200, 400, or 800 ml per pot), three levels of SAR (4, 16, or 64) and three strains of Rhizobium phaseoli (K-17, K-47, or K-52) were used. The treatments were replicated with all possible combinations. Data were subjected to analysis of variance, multiple comparisons, and path coefficient analysis.

A series of research studies have recently identified an issue called strain localization in welded wire reinforced (WWR) members. This phenomenon reportedly concentrates strains at welded cross wire locations and severely limit ductility. Those that identified the phenomenon used it to imply that WWR is unsafe because it does not warn of failure. This dissertation is investigating details to mitigate the strain localization effect and demonstrate the WWR can be used safely. A moment curvature analysis is developed using Response2000 program and calibrated using experimental data. Parametric study was developed to present a recommendation of details and minimum reinforcement required for WWR slabs. The effect of different types of WWR coating on mechanical properties were investigated. The dissertation next examined the effects of strain rate on the mechanical properties of WWR and traditional rebar. In total, fifty four slabs have been constructed using WWR and rebar with various cross wire spacing, using a realistic design. The strain localization phenomenon was not demonstrated, but WWR slabs are somewhat less ductile than traditionally reinforced members. The WWR members were shown to provide adequate ductility for warning of impending failure visually and with a well-accepted ductility measure. The WWR members were also shown the ability of load redistribution. The effect of coating demonstrates that both galvanizing WWR and coating WWR with epoxy has a positive effect on mechanical properties, along with adding corrosion resistance. The effect of strain rate shows that increase in loading rate tend to increase the yield and ultimate stresses and percent area reduction, however the loading rate increase does not have a significant effect on elastic modulus, elongation and uniform elongation.

La polyvalence de la technique de track-etching a permis d’étudier plus avant l’effet piezoélectrique direct et indirect d’un film polarisé en poly(fluorure de vinylidène) PVDF en créant des membranes nanostructurées hybrides de nanofils de nickel (Ni NWs)/PVDF. Les propriétés magnétiques du nanofil de nickel, telle que la magnétorésistance anisotrope (AMR), ont été exploitées afin d’étudier la réponse de l’aimantation à la déformation mécanique de la matrice PVDF. En particulier, les déformations ont été induites soit par contrainte thermo-mécanique, soit par contrainte électromécanique (effet piezoélectrique indirect). La sensibilité d’un nanofil unique a permis de déterminer l’amplitude et la direction de la contrainte mécanique exercée à l’échelle nanométrique par la matrice PVDF. La résistance exceptionnelle de la réponse piezoélectrique directe du film PVDF polarisé à l’irradiation, telle que l’irradiation aux ions-lourds accélérés et aux électrons (domaine de doses < 100kGy) a été observée. Mis à part la conservation de la réponse piezoélectrique, les défauts engendrés par l’irradiation dans ce domaine de dose (scissions de chaines, augmentation de phase crystalline, réticulations) ont eu un impact significatif sur la structure du matériau polymère. L’ensemble de ces défauts, les uns prépondérants en-dessous de la dose-gel ( 10kGy), les autres au-dessus, forme une compensation d’effets antagonistes qui mènent à une réponse piezoélectrique globalement inchangée. Stimulé par la grande résistance du PVDF à l’irradiation en termes de réponse piezoélectrique, l’idée a été d’exploiter, en vue d’une application dans la récupération d’énergie, le réseau de nanofils de nickel inclus dans la membrane en PVDF polarisé pour étudier l’influence des nanofils de nickel sur la l’efficacité piezoélectrique. La présence du réseau de nanofils de nickel mène à un accroissement non négligeable de l’efficacité piezoélectrique. Reliée à la présence des nanofils, une augmentation de la permittivité diélectrique dans le PVDF nanostructuré a également été enregistrée. Une polarisation interfaciale entre les nanofils de nickel et la matrice PVDF pourrait expliquer cette valeur accrue par rapport au PVDF nanoporeux sans nanofils. / The versatility of the track-etching technique has allowed to investigate deeper the direct and inverse piezoelectric effect of a polarized Poly(vinylidene fluoride) (PVDF) film in building nanostructured hybrid Nickel nanowires (Ni NWs)/PVDF membrane. The magnetic properties of the Ni NW, such as anisotropic magneto resistance (AMR), are exploited to investigate the response of the magnetization to a mechanical deformation of the PVDF matrix. In particular, the deformations were induced either by thermo-mechanical or an electro-mechanical (inverse piezoelectric effect) stress. The sensitivity of the single NW has allowed to determine the amplitude and direction of a mechanical stress exerted at the nano-scale by the PVDF matrix. The outstanding resistance of the direct piezoelectric response of polarized PVDF film to radiation, such as SHI and e-beam, (doses range < 100kGy) was reported. Beyond the conservation of the piezoelectric response, in this dose range, irradiation defects (chain scissions, increase of the crystalline -phase, crosslinking) had a significative impact on the polymer material. All these defects, ones predominant above the gel dose (herein 10 kGy), and the other ones below, compensate their antagonistic effects towards the globally unchanged piezoelectric responses. Motivated by the high radiation resistance of the PVDF in terms of piezoelectric response, the idea was to exploit Ni NWs array embedded in the polarized PVDF membrane to study the influence of the Ni NWs on the piezoelectric response in view of harvesting energy application. The presence of the Ni NWs array leads a non-negligible increase of the piezoelectric efficiency. Related to the presence of the NWs, an increase of the dielectric permittivity in the nanostructured PVDF was also reported. An interfacial polarization between the Ni NWs and the PVDF matrix could explain the higher efficiency value respect to nanoporous PVDF, without NWs.

La conception de souches efficacespour la production de composés d’intérêt offredes potentiels immenses qui restent trop peu exploitéspar manque de lien entre les étapes d’optimisationde la conception de souche et celle dela conduite du bioprocédé.Pour combler ce manque, cette thèse proposeune description des bioprocédés intégrant pleinementle fonctionnement interne des microorganismesimpliqués dans la production decomposés d’intérêt. Cette description permetd’optimiser simultanément la souche et le procédépour maximiser la production d’un composéd’intérêt en respectant les contraintes attachéesà ces deux étapes.Dans un premier temps, une nouvelle classe demodélisation de bioprocédés est développée, àl’interface entre les modèles intracellulaires degestion de ressources et les modèles macroscopiquesusuellement utilisés dans la commandede bioprocédés en bioréacteurs. Dans un secondtemps, des contraintes liées à l’implémentationbiologique de la stratégie de contrôle sont intégréesau problème. Ceci permet d’obtenir uneconception plus réaliste du point de vue de l’ingénieriedes génomes. Enfin, la dernière partiede la thèse montre que la méthodologie présentéejusqu’alors sur un modèle agrégé peut êtreétendue à des représentations détaillées du comportementdes micro-organismes. / The design of efficient strains forthe production of compounds of interest offerstremendous potentials that remain insufficientlyexploited due to the lack of link between theoptimization stages of strain design and that ofbioprocess control.This thesis proposes a description of bioprocessesthat fully integrates the internal functioningof micro-organisms involved in the productionof compounds of interest. This descriptionallows the strain and process to be optimizedsimultaneously to maximize the productionof a compound of interest while respecting theconstraints attached to these two stages.First, a new bioprocess modelling class is developedat the interface between intracellular resourceallocation models and macroscopic modelscommonly used in bioprocess control. In asecond stage, constraints linked to the biologicalimplementation of the control strategy are integratedinto the problem. This provides a morerealistic genome engineering design. Finally, thelast part of the thesis shows that the methodologypresented so far on an aggregate model canbe extended to detailed representations of thebehaviour of micro-organisms.

Purpose: To determine the effect of Strain Counterstrain (SCS) on strength, dynamic balance and subjective sense of instability in individuals with chronic ankle instability (CAI). Subjects: Twenty seven volunteers (17 females and 10 males) between the ages of 18 and 55 (mean ± SD age: 33.6 ± 8.8) with a history of CAI who met the inclusion/exclusion criteria were randomly assigned to the control group (n= 13) and the experimental group (n=14). Methods: All subjects signed an informed consent, completed a demographic questionnaire and the foot and ankle ability measure (FAAM), and underwent a standard evaluation, ankle isokinetic testing and the star excursion balance test (SEBT) at the onset of the study. All subjects participated in a home exercise program and received a SCS treatment or a sham treatment once a week. At four weeks all subjects repeated the initial testing and completed a global rating of change (GROC) form. The primary aim was examined with a 2-way analysis of variance (ANOVA) with the treatment group (SCS versus sham) as the between subjects independent variable and time (baseline and four weeks) as the within subjects independent variable. Results: A significant group-by-time interaction was found for seven directions in the SEBT (p< 0.031) while no significant interaction was found for ankle strength (p>0.76). For subjective measures, no significant group-by-time interaction was found for the FAAM (p>0.548), but the GROC revealed a significant difference (p=0.014) in the mean score for the experimental group (3.92 ± 1.66) when compared to the control group (2.43 ± 1.66). Conclusions: Although SCS does not appear to have an effect on strength and subjective ankle function in subjects with CAI, it appears that SCS can lead to an improvement in dynamic ankle stability and the subjective sense of ankle instability. Recommendations: Continued research on the effectiveness of SCS in CAI and other sprain injuries is needed to confirm the results of this study. Given the significant rate of ankle sprain recurrence in this population, long-term studies are necessary. Lastly, very little evidence exists on the effects of SCS and the theoretical framework of this technique.