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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Highly Reflective Multi-stable Electrofluidic Display Pixels

Yang, Shu 20 April 2012 (has links)
No description available.
102

An Analysis of Highly Qualified Special Education Teachers in High Poverty Urban and Rural Areas

Campbell, Stephen Patrick 30 April 2018 (has links)
The purpose of this study was to provide a descriptive analysis comparing highly qualified and non-highly qualified special education teachers in the 2011-12 Schools and Staffing Survey. It examined how the qualifications of special education teachers varied among K-12 public schools according to the urbanicity of the school and the proportion of students in poverty within a school. Variables included those related to teacher qualifications, demographic characteristics, and school characteristics. The findings demonstrated that there were differences in the demographic characteristics of highly qualified and non-highly qualified special education teachers. There were no statistically significant differences found for urbanicity alone. There were statistically significant differences found for poverty levels. Statistically significant differences were also found for both highly qualified and non-highly qualified special education teachers when poverty quartiles were analyzed by urbanity locales. The findings emphasize the need to provide targeted interventions to promote, retain, and supply all schools with qualified special education teachers. The findings also indicate there is an unequal distribution of highly qualified special education teachers within identified poverty levels and urbanicity. / PHD / The purpose of this study was to provide a descriptive analysis comparing highly qualified and non-highly qualified special education teachers in the 2011-12 Schools and Staffing Survey. It examined how the qualifications of special education teachers varied among K-12 public schools according to the location of the school and the proportion of students in poverty within a school. Variables included those related to teacher qualifications, demographic characteristics, and school characteristics. The findings demonstrated that there were differences in the demographic characteristics of highly qualified and non-highly qualified special education teachers with regard to school poverty levels and poverty levels by urbanicity.
103

Immunological and virological responses in highly active antiretroviral therapy naive patients exposed to isoniazid preventive therapy

Manda, Robert January 2009 (has links)
This study compare immunological and virological outcomes in antiretroviral therapy naïve patients exposed to Isoniazid prevention treatment.Medical records of antiretroviral naïve patients managed in the public sector from 1st January 2006 to 31st December 2006 were analysed.Multivariate analysis of variance showed that each treatment group achieved statistically significant increases in CD4+ cell count and viral load decay at each follow-up time point. Pairwise post hoc contrast tests showed patients in NVPipt-past group and EFVipt-past group to have superior immunological and virological outcomes respectively. / Health Studies / M.A. (Public health)
104

Immunological and virological responses in highly active antiretroviral therapy naive patients exposed to isoniazid preventive therapy

Manda, Robert January 2009 (has links)
This study compare immunological and virological outcomes in antiretroviral therapy naïve patients exposed to Isoniazid prevention treatment.Medical records of antiretroviral naïve patients managed in the public sector from 1st January 2006 to 31st December 2006 were analysed.Multivariate analysis of variance showed that each treatment group achieved statistically significant increases in CD4+ cell count and viral load decay at each follow-up time point. Pairwise post hoc contrast tests showed patients in NVPipt-past group and EFVipt-past group to have superior immunological and virological outcomes respectively. / Health Studies / M.A. (Public health)
105

Extra känslig? : En kvantitativ studie om studenter och vaccination mot svininfluensan / Highly sensitive? : A quantitative study about students and vaccination against the swine flu

Svalmark, Per January 2011 (has links)
Syftet med den här studien är att undersöka vad som skiljer i personlighet mellan studenter som vaccinerade sig mot svininfluensan och studenter som inte vaccinerade sig. Studien genomfördes genom en kvantitativ enkätundersökning på 194 studenter från ett universitet i Svealand. Deltagarna fick besvara psykometriska personlighetstester som mätte känslighet, ångest, depression, sympati och pålitlighet. Därefter utfördes statistiska test i SPSS för att i huvudsak beräkna medelvärdesskillnader. Resultaten visar att vaccinerade studenter är signifikant känsligare än ovaccinerade studenter. Vaccinerade studenter är också mer ångestfyllda men skillnaderna är inte signifikanta. Det finns inga nämnvärda skillnader i depression, sympati eller pålitlighet. Typ av utbildning och kön predicerar heller inte vaccinering. Sammanfattningsvis ska känslighet därmed ses som den viktigaste prediktorn för vilka personer som vaccinerar sig vid pandemier. Resultatet kan generaliseras till den svenska befolkningen eftersom studiens andel vaccinerade motsvarar befolkningens andel vaccinerade. Studiens urval motsvarar däremot inte den svenska populationens genomsnittliga utbildningsnivå. Å andra sidan har utbildningsnivå inte visat sig vara en betydande faktor för hälsoskyddande beteenden i tidigare forskning, varför mitt resultat bör betraktas som betydelsefullt. / The purpose of this study is to examine which personality aspects that are differing from students who got vaccinated against the swine flu, to students who did not get vaccinated. This study carried out a quantitative survey on 194 students from a mid-region university in Sweden. The participants were to answer psychometric personality tests on sensitivity, anxiety, depression, sympathy and dependability. Thereafter, statistical tests were conducted through SPSS, mainly to calculate mean differences. The results conclude that vaccinated students are significantly more sensitive than un-vaccinated students. Vaccinated students are also more anxious but these differences are not significant. There are no notable differences in depression, sympathy or dependability. Type of education and sex do not either predict vaccination. Finally, sensitivity shall be viewed as the most important predictor in a person’s likeliness to get vaccinated at pandemics. The findings can be generalized to the Swedish population because the proportion of vaccinated students in this study corresponds to the proportion of vaccinated people of the Swedish population. However, the sample of this study does not correspond to the educational level of the Swedish population. On the other hand, educational level has not been shown as an important determinant in health protective behaviors in former research literature, why my result should be considered as meaningful.
106

Specific mold filling characteristics of highly filled phenolic injection molding compounds

Scheffler, Thomas, Englich, Sascha, Gehde, Michael 08 March 2016 (has links) (PDF)
Thermosets show excellent mechanical properties and chemical resistance (for most automotive fluids) even at high temperatures up to 300 °C. Furthermore they can be highly efficient processed by injection molding. So they should be particularly suited for e.g. under the bonnet applications. However, the reality shows that thermosets are, except fiber reinforced composites, heavily underrepresented in technical applications. E.g. thermosetting components only account 0,2 % to a vehicle’s weight. Therefore reasons can be found in limited knowledge, e.g. relating mold filling behavior. The objective of the study is to analyze the influence of the mold filling behavior during injection molding of highly filled phenolic compounds on mechanical properties. Injection molding filling studies, mechanical testing and optical microscopy were done while varying mold geometry (injection gate and cavity height), mold temperature and injection rate during injection molding a highly filled phenolic compound. It was found that the mold filling behavior varies with altered injection molding parameters as well as the mold geometry. In consequence of this the mechanical properties change according to the resulting reinforcement orientation. The results can help to improve part and mold design for optimal load transmission.
107

Synthèse, caractérisation et photoréactivité d'oligomères hyperbranchés

Mievis, Isabelle 29 August 2006 (has links)
Depuis une dizaine d'années, les polymères hyperbranchés sont apparus dans la littérature. Ils possèdent un grand nombre de branchements ainsi qu'un grand nombre de groupes terminaux. La structure globulaire des polymères hyperbranchés les empêche de former des enchevêtrements. Il en résulte un avantage décisif pour leur application sous forme de revêtement de surface: les polymères hyperbranchés ont une viscosité plus faible à l'état fondu que les polymères linéaires. Cela permet aisément de les étaler sous forme de films minces sans utiliser de solvant. De plus, les polymères hyperbranchés possèdent un grand nombre de groupes terminaux qui peuvent être fonctionnalisés avec des monomères photoréticulables. Le but du travail de thèse est d'obtenir de nouveaux revêtements de surface, à partir de polymères hyperbranchés ou de polymères fortement branchés, qui trouveront leur application dans l'industrie chimique. La thèse s'articule autour de trois chapitres de synthèse suivis d'un chapitre traitant de la photoréactivité des oligomères linéaires, fortement branchés, et hyperbranchés. La première approche de synthèse envisagée est la copolymérisation alternante radicalaire. Divers maléimides ont été engagés dans des copolymérisations radicalaires avec des allyléthers sans succès. Lorsque ces derniers sont remplacés par des vinyls éthers, une copolymérisation alternante est observée. Néanmoins, une importante irreproductibilité est constatée, certains batchs donnant lieu à une gélification. La seconde voie de synthèse étudiée est l'approche classique de polycondensation de monomères de type AB2 . Le monomère AB2 est obtenu par addition de Michael de la diéthanolamine sur l'acrylate de méthyle. La polycondensation est concomitante avec l'acrylation des fonctions alcools. La compétition entre ces deux réactions limite les masses molaires accessibles bien que les réactions de transestérification soient catalysées par des dérivés du Zr et que la stoechiométrie ait été variée. La troisième voie de synthèse se base aussi sur la réaction de Michael. Des oligomères fortement branchés sont obtenus à partir de 1,6-hexanedioldiacrylate et d'éthylènediamine. Leurs analogues linéaires sont synthétisés en remplaçant l'éthylènediamine par la propylamine. Lors de ces synthèses, il est apparu que les oligomères fortement branchés ont une viscosité supérieure à celle des oligomères linéaires! Les oligomères hyperbranchés et acrylés, les oligomères linéaires et leurs analogues fortement branchés ont été étudiés du point de vue de leur photoréticulation sous rayonnement UV. Contrairement à ce qui était attendu, ils se sont montrés moins réactifs que les produits les plus performants de Cytec-Surface Specialties. Lors de cette étude, l'effet bénéfique des mines tertiaires sur l'inhibition par l'oxygène est apparu plus complexe que décrit dans la littérature.
108

Generating and Manipulating Quantized Vortices in Highly Oblate Bose-Einstein Condensates

Samson, Edward Carlo Copon January 2012 (has links)
This dissertation presents several experimental methods that were devised to generate or manipulate quantized vortices in highly oblate dilute-gas Bose-Einstein condensates (BECs). Studies that involve single vortex dynamics, vortex-vortex interactions, and vortex-impurity interactions are essential in developing a deeper understanding of the nature of superfluidity and in particular, superfluid turbulence. In highly oblate systems, vortex dynamics have a two-dimensional (2D) nature and the resulting superfluid characteristics may be substantially different from those in three-dimensional (3D) superfluids. However, there have been remarkably few experimental studies of 2D vortex dynamics in superfluids. Therefore, to study 2D vortex dynamics and interactions, it is necessary to first develop experimental methods that can generate vortices and vortex distributions in nominally 2D systems, such as highly oblate BECs. Four main experiments are discussed in this dissertation. Two of these experiments generate multiple singly quantized vortices in a relatively stochastic manner leading to disordered vortex distributions. From these two vortex methods, the physics of high vorticity and highly disordered systems may be observed and studied in a highly oblate system. These methods may prove useful in studies of 2D quantum turbulence. The other two experiments involve newly developed techniques for controlled generation and manipulation of vortices. One of these methods creates multiply quantized pinned vortices with a control in the generated vorticity. The other method reliably creates a pair of singly quantized vortices of opposite circulation, whose positions can be easily manipulated after creation, such that they can be placed in any location within the BEC. The two techniques may be scalable to higher number of vortices and may prove useful in superfluid dynamics and vortex interactions that require repeatable vortex distributions. Taken together, these tools and methods may be applicable to many further studies of vortex physics in highly oblate BECs.
109

Plasma Characterization & Thin Film Growth and Analysis in Highly Ionized Magnetron Sputtering

Alami, Jones January 2005 (has links)
The present thesis addresses two research areas related to film growth in a highly ionized magnetron sputtering system: plasma characterization, and thin film growth and analysis. The deposition technique used is called high power pulsed magnetron sputtering (HPPMS). Characteristic for this technique are high energy pulses (a few Joules) of length 50-100 µs that are applied to the target (cathode) with a duty time of less than 1 % of the total pulse time. This results in a high electron density in the discharge (>1x1019 m-3) and leads to an increase of the ionization fraction of the sputtered material reaching up to 70 % for Cu. In this work the spatial and temporal evolution of the plasma parameters, including the electron energy distribution function (EEDF), the electron density and the electron temperature are determined using electrostatic Langmuir probes. Electron temperature measurements reveal a low effective temperature of 2-3 eV. The degree of ionization in the HPPMS discharge is explained in light of the self-sputtering yield of the target material. A simple model is therefore provided in order to compare the sputtering yield in HPPMS and that in dc magnetron sputtering (dcMS) for the same average power. Thin Ta films are grown using HPPMS and dcMS and their properties are studied. It is shown that enhanced microstructure and morphology of the deposited films is achieved by HPPMS. The Ta films are also deposited at a number of substrate inclination angles ranging from 0o (i.e., facing the target surface) up to 180 o (i.e., facing away from the target). Deposition rate measurements performed at all inclination angles for both techniques, reveal that growth made using HPPMS resulted in an improved film thickness at higher inclination. Furthermore, the high ionization of the Ta atoms in HPPMS discharge is found to allow for phase tailoring of the deposited films at all inclination angles by applying a bias voltage to the substrate. Finally, highly ionized magnetron sputtering of a compound MAX-phase material (Ti3SiC2) is performed, demonstrating that the HPPMS discharge could also be used to tailor the composition of the growing Ti-Si-C films. / On the day of the public defence of the doctoral thesis, the status of articles III and IV was Submitted. The titles of papers VI and VII changed between their manuscript forms and when they were published.
110

Importance Sampling to Accelerate the Convergence of Quasi-Monte Carlo

Hörmann, Wolfgang, Leydold, Josef January 2007 (has links) (PDF)
Importance sampling is a well known variance reduction technique for Monte Carlo simulation. For quasi-Monte Carlo integration with low discrepancy sequences it was neglected in the literature although it is easy to see that it can reduce the variation of the integrand for many important integration problems. For lattice rules importance sampling is of highest importance as it can be used to obtain a smooth periodic integrand. Thus the convergence of the integration procedure is accelerated. This can clearly speed up QMC algorithms for integration problems up to dimensions 10 to 12. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics

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