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Student Number : 9407325P - PhD thesis - Faculty of Human and Social Sciences / This thesis focuses on the challenges a particular group of rural primary school teachers experienced as they implemented a national outcomes-based curriculum through the support of an external agent. It uses Fairclough’s (1991) model of critical discourse analysis and his theory of critical language study as a framework to explore the discourses and practices of this group of South African teachers. Methodologically, this thesis is located in the qualitative paradigm, and uses interviews and observations to systematically probe teachers’ understandings of curriculum and change. Three themes are developed in this thesis. First, the theme of teacher collaboration is presented as a new social practice that the teachers creatively took up during a school development project. It shows that while social and institutional process determined the nature of the project as a social practice, at a situational level, the teachers played a much more determinative role as they shaped the project and its practices in several intriguing ways. Second, the curriculum roles that were discursively produced by the teachers as they struggled to transform their practice from isolation to collaboration are revealed. This demonstrates that while many of these roles were common to all schools, the role of the teacher as leader emerged in only two of the schools. And third, through analysing the lessons taught by this group of teachers in their classrooms, the tacit knowledge of pedagogy and content on which their practice was based is made explicit. These themes provide opportunities for certain common sense assumptions about teacher collaboration, leadership, learning and practice to be interrogated in terms of their applicability to the schools in the project. The thesis concludes with a discussion of the possibilities that still exist for teacher educators to enhance understanding of what happens inside traditional rural schools.

In dieser Arbeit wurden nanostrukturierte Oberflächen durch Immobilisierung von Gold- und Silber¬nanopartikeln mit Organosilanen hergestellt und bezüglich ihrer Eigenschaften als Substrate für die oberflächenverstärkte Raman-Streuung (SERS) untersucht. In Experimenten zum Einfluss von Partikelgröße und -anordnung auf die plasmonischen Eigenschaften wurden wesentliche Erkenntnisse für die Optimierung SERS-aktiver Nanostrukturen gewonnen. Durch Kombination experimen¬teller Untersuchungen, unter Verwendung von spektroskopischen und bildgebenden Ver¬fahren, mit elektro¬dynamischen Simulationen der lokalen Felder, wurden Zusammen¬hänge zwischen den plasmo¬nischen und nanoskopischen Eigen¬schaften von Partikeln auf Oberflächen und ihren SERS-Eigenschaften hergestellt. Die nanostrukturierten Oberflächen weisen hohe und über einen weiten Analyt-konzentrations¬bereich stabile Verstärkungsfakoren bei hoher mikros¬kopischer Homo-genität der Verstärkung auf. Dies macht sie zu geeigneten Substraten für quantitative Anwendungen von SERS. Das Potenzial der nano-strukturierten Ober¬flächen für den Einsatz in analytischen Fragestellungen wurde anhand mehrerer Anwendungen gezeigt. Durch simultane Immobilisierung verschiedener Nano¬partikel unter Verwendung desselben Linker¬moleküls wurden erstmalig Ober¬flächen mit definierten plasmonischen und funktionellen Eigen¬schaften repro¬duzierbar erzeugt. Diese neuartigen Mischsubstrate wurden in der Verfolgung katalytischer Reaktionen eingesetzt, wodurch erstmals Reaktions-konstanten solcher Reaktionen mittels SERS bestimmt werden konnten. Die Ergebnisse der Arbeit legen einen breiten Einsatz der plasmonischen nano¬struk-turierten Ober¬flächen in der Zukunft nahe. Dieser reicht von Untersuchungen in der Kata-lyse¬forschung über mikroskopische Anwendungen von SERS bis zur Verwendung in der klinischen Diagnostik. / Within this work nanostructured surfaces were generated by immobilization of gold and silver nanoparticles with organosilanes and characterized regarding their suitability as substrates for Surface-enhanced Raman scattering (SERS). Essential knowledge for the optimization of SERS-active nanostructures could be found by experimental invest-igations on the influence of particle size and assembly on the plasmonic properties. Through combined experimental investigations, including spectroscopic and imaging techniques, and electrodynamic simulations of local fields, the plasmonic and nanoscopic properties of particles on surfaces were related to their SERS-properties. The nanostructured surfaces exhibit high and, over a wide range of analyte concentration, stable enhancement factors with high microscopic homogeneity. Therefore immobilized nanostructures are suitable substrates for quantitative SERS. The potential for the use of the nanostructured surfaces in analytical problems was shown in various applications. Signal fluctuations that can occur in the detection of complex analyte mixtures can be significantly reduced by immobilization of the nanoparticles. This offers the possibility to use multivariate statistical methods for automated classification and identification of molecule mixtures but also for multiplexing and imaging by SERS. Simultaneous immobilization of gold and silver nanoparticles and gold and platinum nanoparticles using the same linker molecule allowed for the first time to generate surfaces with defined plasmonic and functional properties with low cost and high reproducibility. These new mix and match-substrates were used to follow catalytic reactions and determine reaction constants of such reactions for the first time using SERS. The outcome of this work suggests a wide range of applications of plasmonic nanostructured surfaces in the future. This includes the investigation of catalysis, microscopic applications of SERS and clinical diagnosis.

To offer better solutions for the recycling of salt cake from secondary aluminum melting, several innovative investigations were carried out based on hydrometallurgical and pyrometallurgical views. Thermal diffusivity measurements as a function of temperature on salts-Al composites having various compositions (0, 2, 4, 6, 8, 10, 12wt pct metallic Al) were carried out. Its attempt to derive theoretical relationships between aluminium contents in the salt-Al composites and the thermal conductivities so that these would serve as calibration curves for industrial samples taken out from secondary aluminium re-melting at a later stage. The AlN hydrolysis behavior in NaCl solution was investigated by immersing pure AlN powder in deionized water, 0.3mol/l NaCl aq, 0.6mol/l NaCl aq and NaCl solution respectively with CO2 bubbling at 291K. The results showed that AlN powder underwent enhanced hydrolysis in NaCl aq than that in deionized water, while, the introduction of CO2 was found to hinder the hydrolysis even in the presence of NaCl. The characterization of the products after hydrolysis was carried out using XRD, SEM and TEM analyses. It was shown that the hydrolysis process included a slow-reaction period involving the dissolution of aluminum hydroxide layer around raw AlN particle, followed by the precipitation of aluminum hydroxide gel and the crystallization of boehmite, bayerite and gibbsite. The effects of sodium chloride concentration on the hydrolysis behavior are presented. The leaching process in CO2-saturated water showed that, at a solid to liquid ratio of 1:20 and 3h at 291K, the extraction of Na and K from the dross could be kept as high as 95.6% and 95.9%, respectively. At the same time, with continuous CO2 bubbling, the mass of generated NH3 during the leaching process decreased significantly, also the escaping NH3 gas decreased from 0.25mg in pure water down to &lt;0.006mg. The above results showed that the introduction of CO2 causes hindrance to the hydrolysis of AlN, meanwhile, effective absorption of ammonia. The plausible mechanisms for the observed phenomena are discussed. The concept of the leaching of the salt cake by carbonated water and the consequent retention of AlN in the leach residue opens up a promising route towards an environment-friendly recycling process for the salt cake viz. recovery of the salts, utilization of CO2 and further processing of the dross residue, towards the synthesis of SiAlON from the leach residues.   In alternative route to the processing of salt cake, the ammonia gas evolved by hydrolysis of AlN was collected by CO2-saturated water during water leaching at 373K. The products, i.e. ammonium carbonates which are free of chlorides, has application as a fertilizer, besides that, this method also has the advantage of fixing carbon from CO2, which is the subject of many investigations around the world. The oxidation behavior of composites SiMgAlON phases (β-SiAlON, MgAlON and 15R) synthesized from the residue during the leaching treatment of salt cake and corresponding synthetic samples was investigated in air by thermogravimetric measurements. The oxidation studies reveal the effects of impurities, namely, Fe2O3 and CaO present in the salt cake residue. From the view of kinetics, the addition of Fe2O3 brings a lower activation energy and more aggressive oxidation. The additive of CaO caused the shrinkage during the synthesis and liquid formation during the oxidation above 1673K, thus retard the oxidation rate. The impurities of CaO and Fe2O3 in the leaching residue can result in an aggressive oxidation at low temperature and a protective oxidation at temperatures above the eutectic point. From the view of phase evolution, with the progress of oxidation, the composition of the material being oxidized moved towards the Al2O3-rich corner of MgO-Al2O3-SiO2 or CaO-MgO-Al2O3-SiO2 phase diagrams relevant to SiMgAlON composite. At lower temperatures, the addition of Fe2O3 and CaO facilitated the formation of cordierite and anorthite, respectively. With the increasing of temperature, islands of silicate melt were formed dissolving these oxides, with the liquidus temperature getting lowered as a consequence. The liquid phase formed engulfed the adjacent solid phases providing strong mobility for the cations and enabling the crystal growth. As a result, intermediate products, i.e. cordierite, anorthite, spinel, which formed earlier during oxidation are found to get dissolved in the liquid phase. / <p>QC 20120912</p>

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Low Earth Orbit (LEO) satellite networks have revolutionized space internet access, offering better network performance than previous alternatives. While being the best option for space internet access, it does not yet compete with terrestrial networks in latency and bandwidth. The QUIC transport protocol was developed for Hypertext Transfer Protocol (HTTP) to reduce page load times and work better in low-bandwidth and high-loss networks than the Transmission Control Protocol (TCP). Studies have shown that QUIC performs well for small file sizes, which can be achieved by using compression. This thesis investigates whether combining QUIC as a general data transfer protocol with lossless compression enhances encrypted data transmission in a LEO satellite network. To test this, a program consisting of a client and server deployed on a LEO satellite network emulator is developed, where files with increasing sizes are compressed and sent using both QUIC and TCP in various network conditions. Results indicate that QUIC should be paired with lossless compression for file sizes up to 1MB. It should not be implemented for file sizes above 1MB in low-loss and high-bandwidth conditions, while it can be implemented in medium to poor conditions.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2016-05-16T15:21:58Z No. of bitstreams: 1 Sidney Cabral Lourenco.pdf: 3471263 bytes, checksum: 3e2de93e28a9f0ae2e12e39b5b3d160b (MD5) / Made available in DSpace on 2016-05-16T15:21:58Z (GMT). No. of bitstreams: 1 Sidney Cabral Lourenco.pdf: 3471263 bytes, checksum: 3e2de93e28a9f0ae2e12e39b5b3d160b (MD5) Previous issue date: 2016-03-15 / This present study investigates the teachers participating in the process of implementation of teachers training policies and curricular policies of the SEE-SP, taken here as those who are in the process end – want to receive the training, want to act as implementing agents to exercise teaching in the classroom. The goal pursued was to map and interpret the perceptions, impressions and elaborations of teacher on the continuous training policies of the SEE-SP, on the State curriculum, on aspects of professional practice and on the participation in the Enhance Management and Education (MGME) as teacher students. The research focuses on a public school located in the city of São Paulo, having as subject two Science teachers who attend the MGME course in 2013 It uses the qualitative methodology and the instruments of collection of data are semi-structured interviews, questionnaire with open questions and a analysis of official documents governing the Program. The research is based on the following authors: Bioto-Cavalcanti, Carvalho, Day, Gatti, Hargraves, Imbernón, Moreira, Nóvoa, Lahire. The collected datas allowed a reflection on the continued training and the implementation of Official Curriculum of the São Paulo State. At the same time, it presents a documental overview of course 1 Enhance Management and Education (MGME) – Training of Trainers and of course 2 Enhance Management and Education (MGME) – Training of Science Teachers, emphasizing the course 2. Finally, parts of the interviews, highlighting the perceptions of the course and the execution in the classroom. / El presente estudio investiga los profesores que participan de la acción de implementación de las políticas de formación y de las políticas curriculares de la Secretaria Estadual de Educación de São Paulo, puntuados como aquellos que están en la extremidad del proceso – sea recibiendo la formación, sea actuando como agentes de la implementación al ejecutar la práctica docente en el aula. El objetivo fue mapear e interpretar las percepciones, las sensaciones y las elaboraciones de los profesores acerca de las políticas de formación continuada de la Secretaria Estadual de Educación de São Paulo, centradas en el currículo del gobierno, y enlazadas con el ejercicio profesional y con relación a la participación de los profesores en el curso Mejor Gestión, Mejor Enseñanza. La investigación está centrada en una escuela pública, ubicada en la ciudad de São Paulo, teniendo como sujetos dos maestros de ciencias naturales que realizaron el curso MGME en 2013. La metodologia que se aplica es la cualitativa, y los instrumentos de colecta de datos son las entrevistas semiestructuradas, cuestinarios con preguntas abiertas, además de los análisis de los documentos oficiales que respaldan el programa. La investigación está fundamentada en los seguientes autores: Bioto- Cavalcanti, Carvalho, Day, Gatti, Hargraves, Imbernón, Moreira, Nóvoa, Lahire. Los datos apuntados permitieron una reflexión acerca de la formación continuada y la implementación del Currículo Oficial del estado de São Paulo. Presentase simultáneamente un panorama documental de los cursos 1- Mejor Gestión, Mejor Enseñanza – Formación de Formadores; 2- Mejor Gestión, Mejor Enseñanza – Formación de Profesores de Ciencias Naturales. Al fin, trechos de las encuestas, resaltando la percepción de los sujetos con relación al curso y su práctica de enseñanza y la práctica aula. / O presente estudo investiga os professores que participam do processo de implementação das políticas de formação de professores e das políticas curriculares da SEE-SP, tomados aqui como aqueles que estão na ponta do processo – quer recebendo a formação, quer agindo como agentes da implementação ao exercerem a docência em sala de aula. O objetivo perseguido foi mapear e interpretar as percepções, impressões e elaborações dos professores sobre as políticas de formação continuada da SEE-SP, sobre o currículo do Estado, sobre aspectos do exercício profissional e sobre a participação no Melhor Gestão, Melhor Ensino como cursistas. A pesquisa focaliza uma escola pública paulista localizada na cidade de São Paulo, tendo como sujeitos dois professores de Ciências que realizaram o curso MGME no ano de 2013. Utiliza-se a metodologia de cunho qualitativo, cujos instrumentos de coleta de dados são entrevistas semiestruturadas, questionário com questões abertas, além de uma análise dos documentos oficiais que regem o referido Programa. A pesquisa está fundamentada nos seguintes autores: Bioto-Cavalcanti, Carvalho, Day, Gatti, Hargraves, Imbernón, Moreira, Nóvoa, Lahire. Os dados levantados permitiram uma reflexão sobre formação continuada e a implementação do Currículo Oficial do Estado de São Paulo. Paralelamente, apresenta-se um panorama documental do Curso 1 Melhor Gestão, Melhor Ensino – Formação de Formadores e do Curso 2 Melhor Gestão, Melhor Ensino – Formação de Professores de Ciências, dando ênfase no Curso 2. Por fim, trechos das entrevistas, destacando a percepção dos mesmos em relação ao curso e sua prática em sala de aula.

The economic and population growth have led to the increased volumes of municipal solid waste in South Africa, hence more pressure to the waste management facilities. Municipal solid waste management is a by-product of everyday living, this is the reason why there is an environmental burden caused by waste to the environment. This study was conducted in Pretoria within the three sampled areas, namely: Garsfontein, Marabastad and Pretoria Central Business District (CBD). The rationale of the study was to establish the influence and effects of biographic factors (age, marital status, educational background, gender) and religious conviction on littering. This project constitutes both qualitative and quantitative data collection methods. About 150 of the questionnaires were administered to each of the three sampled areas. Therefore, the overall proportion of the respondents was 450. Visual inspection was done in all the three sampled areas to observe the littering status quo and waste management situation in these particular areas. The visual inspection uncovered very interesting findings. It was established that Marabastad was cleaner in the morning than in the late hours while Garsfontein was clean throughout the day. Another problem that was discovered, amongst others was that of the condition of the bins in Marabastad and Pretoria Central Business District (CBD) which was bad compared to Garsfontein. From the questionnaire, it was found that the 72% of elderly respondents (< 36 yrs) are more environmental conscious than the young people (18-35 yrs) who 83% of them claim to litter when there is no bin. Further, among young people, 78% said litter cigarette butts and 93% of these said better street cleanliness would help reduce littering. 72% of adults said religious convictions would help reduce littering. The chi-square and correlation coefficient statistical data analysis methods were used to establish the relationship between different biographic and religious variables. Gender, marital status, monthly income, age and religious conviction were all found to have significant effects on issues regarding littering in the city. / Environmental Sciences / M. Sc. (Environmental Science)