Made available in DSpace on 2014-10-09T12:53:55Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:31Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP / FAPESP:03/08041-6

Made available in DSpace on 2014-10-09T12:53:55Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:31Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho apresenta resultados de estudos e caracterizações de Conjuntos Eletrodo/Membrana (MEAs) de Células a Combustível a Membrana Polimérica (PEMFC). Algumas condições de operação de células e diferentes processos de produção de MEA foram investigados. A técnica de Espectroscopia de Impedância Eletroquímica (EIE) (em situ - 0 a 16 A) foi usada \"on-line\" como uma ferramenta de diagnóstico, relativa ao desempenho de célula. As medidas de EIE foram feitas através do Sistema de EIE para células a combustível FC350 (GAMRY), junto a um PC4 Potentiostato/Galvanostato e conectado à carga dinâmica (TDI) para experimentos de EIE \"on-line\" (100 mHz - 10 kHz, dU = 5 mV). MEAs com 25 cm2 de área ativa, usando eletrocatalisadores PtM/C 20 % (M = Ru, Sn ou Ni) fabricados usando o Método de Redução por Álcool (MRA). A tinta catalítica foi diretamente aplicada no Tecido de Carbono (GDL) e este prensado na membrana de Nafion® (105). MEAs usando eletrocatalisadores Pt/C e PtRu/C 20 % da E-TEK foram fabricados para comparação. Todos os cátodos foram confeccionados com Pt/C 20% da E-TEK. Foram fixadas as concentrações de metal nobre em 0,4 mg Pt.cm-2 no anodo e 0,6 mg Pt.cm-2 no catodo (E-TEK). Diagramas de Nyquist dos MEAs com Pt/C e PtRu/C da E-TEK ou PtM/C MRA apresentaram as mesmas resistências de ôhmicas para os MEAs. Este fato pode ser explicado por supressão de aglomerados durante o processo de preparação do MEA ou pela homogeneidade do eletrocatalisador ancorado ao carbono. Também pôde ser observado, a baixas densidades atuais que há uma diferença de desempenho significante entre o eletrocatalisadores da ETEK e os preparados pelo MRA. Os resultados das curvas de polarização confirmaram que PtM/C MRA apresentara um aumento de atividade para as células alimentadas com metanol e etanol. A técnica de EIE se mostrou eficiente para a avaliação do método de preparação dos MEAs e do desempenho da célula, os resultados de EIE mostraram uma coerência na escolha do modelo do circuito elétrico para os MEAs utilizando hidrogênio, metanol e etanol. Esta coerência indica que outras resistências não consideradas no modelo não são relevantes na resistência total dos MEAs. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP / FAPESP:03/08041-6

Magister Artium (Development Studies) - MA(DVS) / This exploratory study is based on the case of the Rusitu Valley, a low income rural community in Zimbabwe. Data was collected using largely qualitative methods and quantitative methods were used to obtain supportive descriptive statistics. Information elicited from focus group discussions conducted with members of the Rusitu Valley community as well as responses obtained from a brief structured questionnaire were used to abstract the Rusitu Valley as a complex adaptive system. Input from in-depth interviews with government representatives in energy policy, local government and non-governmental organisations as well as a review of secondary sources was used to support the analysis and confirm the contextual validity of the study. This study revealed that there is intimate connection between renewable energy technologies and sustainable community development. A key finding was that the contribution of renewable energy technologies in Rusitu Valley is mostly towards the economic dimensions of the community and is relatively limited with regard to social and environmental dimensions. Therefore, this study concluded that renewable energy technologies have not sufficiently contributed towards sustainable community development in the Rusitu Valley. This study also found that the contribution of renewable energy technologies is constrained not only by internal limitations but also external factors. A conclusion drawn from this study was that effective contribution of renewable energy technologies towards social, economic and environmental facets can be enhanced through mainstreaming of renewable energy in policy and planning, as well strengthening institutions and local capacity which would have the overall effect of sustainable community development in low income communities

Orientadores: José Euclides Stipp Paterniani, Túlio Assunção Pires Ribeiro / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-29T00:00:03Z (GMT). No. of bitstreams: 1 Santos_FlaviaFerreiradeSouzados_D.pdf: 6754875 bytes, checksum: 9a804a4e184846e60d2063d6b1aa1326 (MD5) Previous issue date: 2015 / Resumo: O nãotecido sintético é um material de fácil obtenção e baixo custo, cujo uso na filtração lenta juntamente com areia acarretou em resultados satisfatórios, em termos de qualidade de água produzida e facilidade de operação. Esta pesquisa teve como objetivo avaliar o desempenho de um filtro lento com meio filtrante constituído exclusivamente por nãotecido sintético em diferentes espessuras e compará-lo ao desempenho de um filtro lento de areia tradicional. Construiu-se um sistema piloto de filtração em que os dois filtros lentos operavam em paralelo sob influência de três taxas de filtração (3, 6 e 9 m3.m-2.dia-1). No decorrer das carreiras de filtração foram monitorados a evolução da perda de carga de cada filtro, os parâmetros físico-químicos e bacteriológicos da água bruta e água tratada pelo filtro de areia e por cada uma das 12 espessuras (entre 1 e 40 cm) do filtro de nãotecido. O filtro lento de nãotecido proporcionou carreiras de longa duração, quando comparado ao filtro de areia, além de reduzir a frequência e a complexidade do processo de limpeza do filtro. A formação da schmutzdecke foi observada na camada superficial do filtro de nãotecido, o qual teve período de amadurecimento semelhante ao filtro de areia, aproximadamente 15 dias. O desempenho satisfatório do filtro lento de nãotecido abrangeu as três taxas de filtração avaliadas. Em termos de remoção de cor aparente e turbidez da água bruta, atendeu os padrões de potabilidade de água designados pela legislação vigente. E, em termos de remoção de bactérias heterotróficas, coliformes totais e E. coli, o filtro de nãotecido alcançou eficiência superior a 99,5%, estatisticamente similar ao filtro lento de areia. Os resultados obtidos indicam que a espessura ótima de nãotecido sintético para remoção de cor aparente e turbidez da água seria de 25 cm, e sugerem que a espessura de 15 cm de nãotecido seria suficiente para remoção de bactérias, com possibilidade de emprego de taxa de filtração considerada elevada para o tratamento por filtração lenta (9 m3.m-2.dia-1). Desta forma, concluiu-se que o meio filtrante constituído exclusivamente por nãotecido sintético de 25 cm de espessura tem potencial para substituir a areia no tratamento de água por filtração lenta, uma vez que obteve desempenho similar ao filtro lento de areia, além de simplificar os procedimentos operacionais e de manutenção do filtro / Abstract: Non-woven synthetic fabric is an easily available and low-cost material which has brought satisfactory results in terms of both the quality of produced water and its operational value. The aim of this research is to assess the performance of a slow filter made up exclusively of non-woven synthetic fabrics of a number of different thicknesses and to compare it to that of a traditional sand filter. A pilot filtering system was built where the two slow filters operate in a parallel way under the influence of three filtering rates (3, 6 and 9 m3.m-2.d-1). Along the filtering runs the evolution of the headloss and the physical-chemical and bacteriological parameters of both raw water and water treated through the 12 thicknesses (ranging from 1 to 40 cm) of non-woven were monitored as well as that filtered through sand. The slow non-woven filter yielded long-term runs when compared to the sand filter, as well as reducing the frequency and complexity of the filter¿s cleaning process. The formation of schmutzdecke was observed on the superficial layer of non-woven filter, a process which had a similar maturing period to that of the sand filter, approximately 15 days. The satisfactory performance of the slow non-woven synthetic fabric filter covered all three filtering rates. In terms of the removal of apparent color and turbidity of raw water it met the drinkability standards set by the existing legislation. In terms of the removal of heterotrophic bacteria, total coliform and E. coli the non-woven filter obtained an efficiency level above 99,5%, statistically similar to the slow sand filter. The results indicate the optimal thickness of non-woven synthetic fabric for apparent colour and turbidity removal to be 25 cm, and suggest that a 15cm thickness would be enough to remove, with the possibility of using filtering rates considered elevated by slow filtering treatment standards (9 m3.m-2.d-1). Therefore, it concludes that the filter medium constituted exclusively of 25-cm-thick non-woven synthetic fabric has the potential to substitute sand in slow-filtering water treatment once it has obtained similar performance to the slow sand filter / Doutorado / Agua e Solo / Doutora em Engenharia Agrícola

Thesis (MScFor)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Grobbelaar, F.R. 2000. A methodology to aid in appropriate technology decision-making for developing countries. M.Sc thesis. University of Stellenbosch. In the process of selecting what we believe to be suitable technology for timber harvesting and transport, economics are usually the determining factor, whether in the form of capital investment or personnel cost. Internationally we see a move towards mechanisation in forestry for various reasons: e.g., high wages, labour shortage, and occupational safety. The realities of South Africa highlights other issues requiring attention: e.g., high unemployment, skills' shortage, global competition, rampant AIDS pandemic, and a poor safety and security record. This should focus our attention on finding local solutions to the problem of finding suitable or appropriate technology to support South Africa's quest for sustainable development. This thesis attempts to establish a methodology for the objective evaluation of alternative technologies for a specific timber harvesting situation, considering the economic, social and environmental implications. / AFRIKAANSE OPSOMMING: Grobbelaar, F.R. 2000. A methodology to aid in appropriate technology decisionmaking for developing countries. M.Sc tesis. Universiteit van Stellenbosch. Tydens die keuse van sogenaamde toepaslike tegnologie vir houtinoesting en -vervoer is ekonomie meestal die deurslaggewende faktor, hetsy verteenwoordig deur kapitaal belegging of personeelkoste. Internasionaal is daar tans In neiging na meganisasie in bosbou vir In verskeidenheid redes: bv., hoë arbeidskoste, arbeidtekort, en beroepsveiligheid. Die werklikhede van Suid-Afrika beklemtoon egter ander sake wat daadwerklike optrede vereis: nl., hoë werkloosheid, gebrek aan vaardighede, internasionale mededinging, ernstige VIGS pandemie, en In swak veiligheid-en sekuriteit rekord. Dit behoort ons aandag te fokus op die vind van plaaslike oplossings tot die probleem met die keuse van geskikte of toepaslike tegnologie ter bevordering van Suid Afrika se strewe na volhoubare ontwikkeling. Hierdie tesis poog om In metodiek te ontwikkel vir die objektiewe beoordeling van alternatiewe tegnologieë vir houtinoesting binne bepaalde omstandighede, met inagneming van ekonomiese, sosiale en omgewings implikasies.

There is little evidence in the literature that early childhood (EC) teachers are using developmentally appropriate practices (DAP) in implementing computer applications in their classrooms. The purpose of this study was to identify EC teachers' perspectives about the use of developmentally appropriate computer applications and to identify their perspectives on strategies for implementing change toward greater use of developmentally appropriate computer applications. The study was based upon Joseph and Reigeluth's conceptual framework of systemic change processes, which provides educators with the foundation to achieve sustainable changes. The research questions that guided this qualitative case study were designed to obtain teachers' perspectives about the use of DAP while embedding technology into EC classrooms and strategies that might be used in encouraging use of DAP computer applications. Data collection included semistructured interviews with 10 EC teachers in one school and reviews of relevant documents. Data from interviews and document reviews indicated a perceived need for more integration of developmentally appropriate computer technology in the classroom and for increasing teachers' knowledge of DAP through training and staff development. Recommendations for schools included finding more and varied technology funding sources, placing greater school emphasis on the importance of a learning organization, and increasing stakeholder involvement. For teachers, recommendations were to develop additional instructional strategies for embedding DAP technology into the classroom. This study has the potential to help stakeholders and EC teachers enhance the fidelity of instruction and students' learning in the classroom.

No description available.

This dissertation presents the design and case study application of a participatory decision-making support tool for appropriate safe water systems development in marginalized low-income communities of the global South. The tool focuses on the resolution of two key design decisions: 1) selecting the appropriate level of application (i.e. household or community level) for a safe water system; and 2) selecting an appropriate water treatment technology (or technologies). The tool breaks the process down into four stages. First are pre-implementation steps which develop a contextualized, baseline understanding of the local community. Second is community-based field research, including focus groups and key informant/informal interviews, to investigate the two key design questions by exploring local preferences, capacities, and circumstances with community-members, government officers, NGO workers, and other stakeholders. Third are analytical steps to integrate information from baseline, informal, and primary research to generate recommendations on the two key design questions. This includes a comparative analysis of household and community level systems; a technology feasibility flowchart; performance assessments of technological alternatives with respect to appropriate technology criteria; and a multi-factor analysis to integrate information from the preceding analytical steps. Fourth are community forums in which further participatory action and research is planned on the basis of the recommendations emerging from the tool. Through these steps, the decision-making support tool guides implementing organizations through the stages of safe water systems design and planning in a manner that centres local people in the process. The tool weaves together several theoretical and methodological strands including humanitarian engineering, post-normal science, appropriate technology, participatory development, grounded theory, engineering decision-making, and water treatment engineering. The case study application of the decision-making support tool was conducted in a marginalized peri-urban community called Mylai Balaji Nagar in Chennai, India. This indicated that a household level approach is more appropriate for the case study community and that the TATA Swach filter, alum coagulation with chlorination, or boiling, in order of decreasing suitability, may be appropriate technologies for household application in the case study community. / Degree: Doctor of Philosophy Department: School of Engineering Advisor: Hall, Kevin / International Development Research Centre (IDRC)

A crucial factor to enable low-income families to participate in the gradual development of their homes is to find a link between their building activities and those of the large-scale building sector. Amidst technological development and increasing demand for housing, the large-scale sector, such as government and private groups, resorted to industrialised housing to replace traditional and conventional building materials and methods. Industrialisation, however, resulted not only in expensive and inappropriate dwellings but also eliminated homeowners from the building process and management of their homes. To bring back the homeowners in the building process, the shift was towards the production of small components and partial prefabrication. / Following the same thrust, there have been numerous innovative building systems for housing developed in the Philippines in the last two decades. Private entrepreneurs develop these building systems either promoting locally invented systems or adapting imported versions. Seeing their potentials, government and private groups are trying to employ them in housing. Despite the growing number of the innovative building systems and the interest to use them, their integration in low-income housing is still limited. / Focusing on Metro Manila, the capital region of the Philippines, the thesis aims to develop a selection model for the effective integration of innovative building systems in low-income housing. The process of integration is not simply using the building systems for mass production of houses but also enabling homeowners to utilise, maintain and sustain them. The proposed model involves sets of selection parameters essential at each stage of the housing delivery based on the homeowners' progressive building process and their criteria for choosing building materials for their homes. To facilitate progressive building and enhance the homeowners' initiative to build, the model also includes design strategies when employing new building systems and suggests the necessary channels to ensure the availability of the building systems, technical assistance and information.

Thesis (Ph. D.)--Michigan State University, 1987. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 268-276).