Made available in DSpace on 2016-06-02T19:56:35Z (GMT). No. of bitstreams: 1 2404.pdf: 4034212 bytes, checksum: 2913adf06c11c92402ccb17ed7a97fa8 (MD5) Previous issue date: 2009-02-27 / Universidade Federal de Sao Carlos / Hydrogen is a clean and renewable source of energy and it is considered the "fuel of the future", because it produces only water during combustion and when it is used as fuel and hydrogen has a high energy yield of 122 kJ/g, which is 2.75 times greater than hydrocarbon fuels. The hydrogen production using microorganisms is a promising area of technological development from a wide variety of renewable and a alternative for this production is to use the anaerobic fluidized bed reactor (AFBR), a promising reactor for hydrogen production. One of the factors that most influence the performance of AFBR is the support material, which should provide resistance to abrasion, porous surface conducive to colonization by microorganisms, easy fluidization to reach and ability to facilitate the transfer of mass between the middle and biofilm. Thus, the objective of this study was to evaluate the influence of different support materials (polystyrene - R1, ground tire - R2 and PET - R3) for the hydrogen production, using three AFBR. Each reactor had a total volume of 4192 cm3, which was used as carbon source 4000 mg.L-1 of glucose, with pH influent around 7.0 and pH effluent of around 5.5, with hydraulic retention time (HRT) between 8 and 0.5 h, with temperature of 30 o C } 1, with heat treatment of the inoculum. The best performance was R2, giving better hydrogen yield production (HY) (2.15 mol-H2.mol-1-glucose), best H2 content in the biogas (52.97%) and showed a higher glucose conversion (90%). However, the R3 was better in the hydrogen production rate (HPR), 1.07 lh-1.L-1, a secondary parameter in the analysis of performance of the reactors. In all reactors, the production volume of hydrogen and H2 content in biogas increased with the reduction of the TDH, 8 pm to 1 HEO yield of hydrogen production increased with the reduction of the TDH, 8 h for 2 h. The major soluble metabolites during H2 fermentation were acetic acid (HAc), butyric acid (HBu), lactic acid (HLa) and ethanol (EtOH), and a small production of propionic acid and R2 was the reactor that more produced HAc and HBu (42.0% e 36.5%, respectively) . The better performance of R2 can be explained by the roughness of ground tire is larger than the other materials used, accumulating a large quantity of attached biomass, and a greater quantity of bacteria hydrogen producing. There was a predominance of bacilli like Clostridium sp. in the biofilm of all support materials. / O hidrogenio e uma fonte de energia limpa e renovavel e e considerado o combustivel do futuro , pois gera somente agua durante sua combustao e apresenta calor de combustao de 122 kJ.g-1, o que representa 2,75 vezes mais conteudo de energia do que qualquer hidrocarboneto. A producao de hidrogenio usando microrganismos e uma promissora area de desenvolvimento tecnologico a partir de uma ampla variedade de fontes renovaveis e uma das alternativas para esta producao e a utilizacao do reator anaerobio de leito fluidizado (RALF). Um dos fatores que mais influenciam o desempenho do RALF e o material suporte, que deve apresentar resistencia a abrasao, superficie porosa favoravel a colonizacao de microrganismos, facilidade para alcancar a fluidizacao e capacidade de favorecer a transferencia de massa entre o meio e o biofilme. Desta maneira, o objetivo deste trabalho foi avaliar a influencia de diferentes materiais suporte (poliestireno - R1, pneu inservivel triturado - R2 e PET - R3) na producao de hidrogenio utilizando tres reatores anaerobios de leito fluidizado. Cada reator possuia um volume total de 4192 cm3, alimentado com meio contendo glicose como fonte de carbono (4000 mg.L-1), com pH afluente em torno de 7,0 e efluente em torno de 5,5, com tempo de detencao hidraulica (TDH) entre 8 e 0,5 h a uma temperatura de 30oC } 1oC, com tratamento termico do inoculo. O melhor desempenho foi do R2, apresentando melhor rendimento de H2 (2,15 mol-H2.mol-1-glicose), melhor conteudo de H2 no biogas (52,97%) e maior conversao de glicose (90%). Entretanto, o R3 foi melhor na producao volumetrica de H2, 1,07 L.h-1.L-1, um parametro secundario na analise de desempenho dos reatores. Em todos os reatores, a producao volumetrica de hidrogenio e o conteudo de H2 no biogas aumentaram com a reducao do TDH de 8 h para 1 h e o rendimento de producao de hidrogenio aumentou com a reducao do TDH de 8 h para 2 h. Os metabolitos soluveis predominantes em todos os reatores foram acidos acetico, butirico, latico e etanol, havendo uma pequena producao de acido propionico, sendo o R2 o que mais produziu acidos acetico e butirico (42,0% e 36,5%, respectivamente). O melhor desempenho do R2 pode ser explicado pela rugosidade do pneu triturado ser maior do que a dos demais materiais empregados, acumulando uma maior quantidade de biomassa aderida e uma maior quantidade de bacterias acidogenicas produtoras de hidrogenio. Houve predominancia de bacilos semelhantes a Clostridium sp. no biofilme de todos os materiais suporte.

The growing diversity of school populations around the world means that for many learners the language of learning in mainstream classrooms is not their first language. The researcher would submit that content-based second language learning in a context such as a Science classroom is considered advantageous as it enables the learner to manipulate a target language such as English in a way which is meaningful. However, Science learners who have yet to achieve communicative competence in English are disadvantaged when it comes to developing a deep understanding of scientific concepts. Many mainstream Science educators have concerns about this significant group of learners who can be left on the periphery of the class to cope as best as they can. Very often educators aim to meet the needs of English Second Language (ESL) learners without any specific knowledge of the strategies which would enhance learning and ensure that learning environments encourage participation and interaction. The learners themselves have not only to deal with language and sociocultural issues but must face the cognitive demands of Science including negotiating its specialized language. The aim of this study was to investigate how the use of English as a language of learning and teaching Science in rural secondary schools in the Vlakfontein Circuit of the Limpopo Capricorn District, influenced the ability of Grade 8 students to learn Science. The focus was on the Grade 8 classes since they are at the threshold of their educational pursuit. The study had two main purposes. The first goal was to describe the current situation with respect to rural secondary school learners and their educators in selected learning environments in Vlakfontein Circuit. The second goal was to bring about improvement in the learners’ situations by employing specifically designed interventions. The study had three focal areas: the language; the teaching and learning environment; and the ESL learner. The investigation was conducted in disadvantaged rural secondary schools in the Vlakfontein Circuit in the Limpopo province. Observations of the Science classes revealed that, even for the learners with very limited English language proficiency there was little ESL specialist support available. The data analyzed was collected using a variety of data collection tools. The main data generation tools were observation, semi-structured interviews and questionnaires. The analysis revealed that learners were lacking in Science register (terminology). This study also found out that non-technical language used in Science lessons affected the learners’ understanding much more than the educators were aware. Educators’ attitudes and beliefs strongly influenced the interaction and participation of ESL learners in Science classrooms. The study also revealed that developing language skills prevented ESL learners from asking questions and answering questions in class and academic progress in Science was impeded by limited opportunities for ESL learners to clarify their understanding. Further, the investigation established that achievement in Science and in education overall was affected by assessment instruments which were infused with specific linguistic or cultural knowledge. The study arrived at a conclusion that the needs of the research students could not be met by a programme based on the traditional format of ESP teaching. Hence, the researcher has recommended a Science Based English Programme (SBEP) which encapsulates several adjustments in orientation methods and materials to meet the ESL learners’ needs. This kind of learning-centred arrangement will allow not only efficiency of SBEP instruction but also allow the kinds of activities that may not be possible in groups with a wide dispersion of interests. However, the extent to which the research learners encountered difficulties with vocabulary suggests that there is a need to investigate more effective methods of dealing with this issue. Needed research could also be directed into the development of a Science glossary with appropriate language levels for ESL learners. This could include technical scientific terms with examples of how terms can be used.From the outcome of the interviews with educators, it is evident that further research is needed concerning the educators’ English proficiency and Science competence in ESL situations. / Teacher Education / D. Ed. (Didactics)

The study focuses on challenges in the development of learner-centred and process-oriented teaching and learning in the learning areas, natural science (NS) and mathematics in South African schools. The aim of NS is to develop scientifically literate learners. The three Learning Outcomes (LOs) and the accompanying Assessment Standards (ASs) should enable learners to understand the science products or system of ideas such as underlying theories and principles. The LOs point out the learner’s abilities to use the sciences products or system of ideas. Educators encounter challenges in the application of the LOs and ASs in teaching and learning activities. Against this background, a mixed method study was conducted in selected schools in the Tshwane South District in Gauteng. Data were gathered by document analysis, focus groups and a questionnaire to gauge how the educators are applying the LOs and ASs. Findings indicated that lessons plans were inadequate and educators were not familiar with curriculum documents. / Science and Technology Education / M. Ed. (Natural Sciences Education)

Welfare of families with children In my thesis I dealt with welfare of families with children, because it is a topic that is relevant to everyday part of human life, and has been since its conception. The aim was to give an overview of the basic institutes of ensuring welfare of these families with respect to the near future. But the focus was not put only at social welfare as such, but I tried to give an overview of the most important institutes as well as other branches of the law, where I find elements of social welfare either in the form of material welfare, or any other form of protection of people with dependent children, as e.g. their advantage over people who do not care of dependent children. The first chapter deals with the security of families who are expecting a child and with the period after his/her birth. Family Safety in this period is mainly based on the legislation sickness, from which was one of my sources when examining this topic. The second chapter describes the circuit of social welfare benefits to which a family, during the period following the birth of a child, is entitled. This chapter is based on the law of the state social support. The third chapter presents a range of benefits in material need and concept of subsistence. Here I primarily discussed the Act on poverty and the law...

This investigative study was undertaken against the background of the recent calls for back to basics by the Schooling 2025 initiative, as well as to address the 2000 and 2009 Review Committees’ reports on the training and development of teachers and on the variable quality of learning support materials. The act of systemic transformation has led to two curriculum revisions taking place within the South African education sector and has inevitably culminated in the identification of shortcomings in teacher development and learning materials. This study has positioned itself to address these shortcomings at pre-service level through the preparation of Mathematics student teachers as prospective Mathematics teachers. In addressing the issue of inadequate training, the focus of the study was not only on cognition, but also on how affect could influence the learning of Mathematics so as to ensure a more encompassing approach in understanding how student teachers learn and do Mathematics. Integrated research on affect and cognition could lead to optimal performance in the teaching and learning of Mathematics and researchers in mathematics education need to acknowledge the role and impact of the affective domain and integrate it into studies of cognition. If learners are going to become competent learners of Mathematics, their affective responses to Mathematics are going to be much more intense than if they are merely expected to achieve satisfactory levels of performance in low-order mathematical skills. In the studies on mathematics cognition, the focus of mathematical competencies is on abilities and capabilities while, in the affective domain, competencies in mathematics are more than the abilities to perform observable tasks. Rather, the focus of the affective competencies lies in the direction, the degree and the levels of intensities of affect constructs (or their variables) that will define mathematical competencies within the affective domain. Evidentiary (qualitative) data from this study supported the contention that affect does influence the learning of mathematics since there were distinct patterns in the overall expressions of participants towards this aspect of the research. The acknowledgment of the concerns of student teachers during field practicum could possibly help in ameliorating these concerns through the identification of what student teachers were mostly concerned about when teaching Mathematics and how, by addressing these concerns, could help improve their teaching skills and abilities. Based on the quantitative evidence, the three subscales of self, task and impact used in the Student Concerns Questionnaire (SCQ) were modified on the basis of factor analysis to a two-factor model (concerns about self-benefit and concerns about learner-benefit). Some of the statistical results were integrated with the narrative data to provide substantive support for the expressions of student teachers. No classical trends, as noted in the concerns theory, could be detected in this study. It was statistically inferred that a majority of Mathematics student teachers who participated in this study were moderately concerned about most of the concerns statements noted in each of the items on the SCQ. In addressing the variable quality of the learning material the study focused on the development and the use of social context learning packages. The utilisation of these learning packages (in an intervention strategy) was aimed at strengthening social context knowledge and education, and explored its role in the translation (if any) of student teacher concerns within a hierarchical spectrum. The evidence on how student teachers perceived the use of these learning packages was recorded during the interviews. Analyses of the verbal data revealed that the participating student teachers agreed with the use of social context learning packages as part of their Mathematics lessons. In sum, the need to prepare effective Mathematics teachers and raise the academic calibre of prospective Mathematics teachers was fundamental to the overall design of this study. It is trusted that curriculum planners and designers will consider the recommendations of this study to address the so-called inadequacies within the education system of South Africa. / Thesis (PhD (Mathematics Education))--North-West University, Potchefstroom Campus, 2013

This investigative study was undertaken against the background of the recent calls for back to basics by the Schooling 2025 initiative, as well as to address the 2000 and 2009 Review Committees’ reports on the training and development of teachers and on the variable quality of learning support materials. The act of systemic transformation has led to two curriculum revisions taking place within the South African education sector and has inevitably culminated in the identification of shortcomings in teacher development and learning materials. This study has positioned itself to address these shortcomings at pre-service level through the preparation of Mathematics student teachers as prospective Mathematics teachers. In addressing the issue of inadequate training, the focus of the study was not only on cognition, but also on how affect could influence the learning of Mathematics so as to ensure a more encompassing approach in understanding how student teachers learn and do Mathematics. Integrated research on affect and cognition could lead to optimal performance in the teaching and learning of Mathematics and researchers in mathematics education need to acknowledge the role and impact of the affective domain and integrate it into studies of cognition. If learners are going to become competent learners of Mathematics, their affective responses to Mathematics are going to be much more intense than if they are merely expected to achieve satisfactory levels of performance in low-order mathematical skills. In the studies on mathematics cognition, the focus of mathematical competencies is on abilities and capabilities while, in the affective domain, competencies in mathematics are more than the abilities to perform observable tasks. Rather, the focus of the affective competencies lies in the direction, the degree and the levels of intensities of affect constructs (or their variables) that will define mathematical competencies within the affective domain. Evidentiary (qualitative) data from this study supported the contention that affect does influence the learning of mathematics since there were distinct patterns in the overall expressions of participants towards this aspect of the research. The acknowledgment of the concerns of student teachers during field practicum could possibly help in ameliorating these concerns through the identification of what student teachers were mostly concerned about when teaching Mathematics and how, by addressing these concerns, could help improve their teaching skills and abilities. Based on the quantitative evidence, the three subscales of self, task and impact used in the Student Concerns Questionnaire (SCQ) were modified on the basis of factor analysis to a two-factor model (concerns about self-benefit and concerns about learner-benefit). Some of the statistical results were integrated with the narrative data to provide substantive support for the expressions of student teachers. No classical trends, as noted in the concerns theory, could be detected in this study. It was statistically inferred that a majority of Mathematics student teachers who participated in this study were moderately concerned about most of the concerns statements noted in each of the items on the SCQ. In addressing the variable quality of the learning material the study focused on the development and the use of social context learning packages. The utilisation of these learning packages (in an intervention strategy) was aimed at strengthening social context knowledge and education, and explored its role in the translation (if any) of student teacher concerns within a hierarchical spectrum. The evidence on how student teachers perceived the use of these learning packages was recorded during the interviews. Analyses of the verbal data revealed that the participating student teachers agreed with the use of social context learning packages as part of their Mathematics lessons. In sum, the need to prepare effective Mathematics teachers and raise the academic calibre of prospective Mathematics teachers was fundamental to the overall design of this study. It is trusted that curriculum planners and designers will consider the recommendations of this study to address the so-called inadequacies within the education system of South Africa. / Thesis (PhD (Mathematics Education))--North-West University, Potchefstroom Campus, 2013

The study focuses on challenges in the development of learner-centred and process-oriented teaching and learning in the learning areas, natural science (NS) and mathematics in South African schools. The aim of NS is to develop scientifically literate learners. The three Learning Outcomes (LOs) and the accompanying Assessment Standards (ASs) should enable learners to understand the science products or system of ideas such as underlying theories and principles. The LOs point out the learner’s abilities to use the sciences products or system of ideas. Educators encounter challenges in the application of the LOs and ASs in teaching and learning activities. Against this background, a mixed method study was conducted in selected schools in the Tshwane South District in Gauteng. Data were gathered by document analysis, focus groups and a questionnaire to gauge how the educators are applying the LOs and ASs. Findings indicated that lessons plans were inadequate and educators were not familiar with curriculum documents. / Science and Technology Education / M. Ed. (Natural Sciences Education)

The growing diversity of school populations around the world means that for many learners the language of learning in mainstream classrooms is not their first language. The researcher would submit that content-based second language learning in a context such as a Science classroom is considered advantageous as it enables the learner to manipulate a target language such as English in a way which is meaningful. However, Science learners who have yet to achieve communicative competence in English are disadvantaged when it comes to developing a deep understanding of scientific concepts. Many mainstream Science educators have concerns about this significant group of learners who can be left on the periphery of the class to cope as best as they can. Very often educators aim to meet the needs of English Second Language (ESL) learners without any specific knowledge of the strategies which would enhance learning and ensure that learning environments encourage participation and interaction. The learners themselves have not only to deal with language and sociocultural issues but must face the cognitive demands of Science including negotiating its specialized language. The aim of this study was to investigate how the use of English as a language of learning and teaching Science in rural secondary schools in the Vlakfontein Circuit of the Limpopo Capricorn District, influenced the ability of Grade 8 students to learn Science. The focus was on the Grade 8 classes since they are at the threshold of their educational pursuit. The study had two main purposes. The first goal was to describe the current situation with respect to rural secondary school learners and their educators in selected learning environments in Vlakfontein Circuit. The second goal was to bring about improvement in the learners’ situations by employing specifically designed interventions. The study had three focal areas: the language; the teaching and learning environment; and the ESL learner. The investigation was conducted in disadvantaged rural secondary schools in the Vlakfontein Circuit in the Limpopo province. Observations of the Science classes revealed that, even for the learners with very limited English language proficiency there was little ESL specialist support available. The data analyzed was collected using a variety of data collection tools. The main data generation tools were observation, semi-structured interviews and questionnaires. The analysis revealed that learners were lacking in Science register (terminology). This study also found out that non-technical language used in Science lessons affected the learners’ understanding much more than the educators were aware. Educators’ attitudes and beliefs strongly influenced the interaction and participation of ESL learners in Science classrooms. The study also revealed that developing language skills prevented ESL learners from asking questions and answering questions in class and academic progress in Science was impeded by limited opportunities for ESL learners to clarify their understanding. Further, the investigation established that achievement in Science and in education overall was affected by assessment instruments which were infused with specific linguistic or cultural knowledge. The study arrived at a conclusion that the needs of the research students could not be met by a programme based on the traditional format of ESP teaching. Hence, the researcher has recommended a Science Based English Programme (SBEP) which encapsulates several adjustments in orientation methods and materials to meet the ESL learners’ needs. This kind of learning-centred arrangement will allow not only efficiency of SBEP instruction but also allow the kinds of activities that may not be possible in groups with a wide dispersion of interests. However, the extent to which the research learners encountered difficulties with vocabulary suggests that there is a need to investigate more effective methods of dealing with this issue. Needed research could also be directed into the development of a Science glossary with appropriate language levels for ESL learners. This could include technical scientific terms with examples of how terms can be used.From the outcome of the interviews with educators, it is evident that further research is needed concerning the educators’ English proficiency and Science competence in ESL situations. / Teacher Education / D. Ed. (Didactics)

This study explores the flawed procurement and delivery of Learner Teacher Support Materials (LTSM) in East London district at public secondary schools in the Eastern Cape province. Poor management of the procurement of LTSM has the result that some schools in the country have limited access to LTSM because of late delivery, non-delivery, incorrect and, or delivery shortages. These problems have contributed to under-achievement in the affected schools and in turn undermine the learners’ constitutional rights and educational aims and goals. Like many other provinces, the Eastern Cape also encountered difficulties with the procurement and delivery of textbooks to various public schools. To investigate the problem, a qualitative and exploratory study was carried out. The data were collected from a sample of 19 participants involved in the three levels of the procurement process; that is, district officials, school principals and the provincial head office officials. The researcher conducted face-to-face interviews using open-ended questions. The research results showed that although the procurement process of LTSM is centralised at the head office level, the other two levels, namely the district office and the school levels, play a significant part. While these levels play an important role in determining and collating the textbook needs, they require additional communication processes and systems to be in place to avoid prolonged timeframes and follow ups that bring about delays of the overall procurement process. Between communication of the relevant guidelines, and collating and submitting book needs information, delays happen along the way at one or more levels and these ultimately lead to either late procurement, late or non-delivery of books to the relevant schools. The study showed that although there are rules, regulations and various policies that serve as guidelines in the procurement process, the actual implementation and monitoring is flawed. The lack of coherence promotes mistrust and conflict between the relevant stakeholders, which in turn brings about minimal consultation on changes relating to effective management processes during procurement and distribution of LTSM. The study recommends changes that are needed to achieve effective management to alleviate problems encountered during the procurement and distribution of LTSM in the East London district public secondary schools / Entrepreneurship, Supply Chain, Transport, Tourism and Logistics Management / M. Com. (Logistics)