Denna kandidatuppsats undersöker hur trafiklärare uppfattar målen med Transportstyrelsens nya kursplan (2006) och hur de undervisar för att eleven ska nå målen i kursplanen. Studien är av explorativ karaktär och därför valdes en kvalitativ ansats med empiri i form av intervjudata. Sex trafiklärare intervjuades och materialet analyserades med meningskoncentrering och kategorisering. Den teoretiska referensramen bygger på Mezirows ”transformativa vuxenundervisning”, samt forskning inom kognitiv neuropsykologi. Resultatet visar att trafiklärarna i studien övervägande är positiva till den nya kursplanen och att de försöker undervisa på ett sätt så att eleven ska nå målen och uppfylla kraven. Till exempel rapporterar samtliga lärare att de jobbar mera med självvärdering, men även med insiktshöjande pedagogiska metoder. Av resultatet framgår att trafiklärarna är mycket negativa till förarprovet som de uppfattar som en begränsande faktor i utbildningssystemet. Av den anledningen är de också pessimistiska till hur nyblivna körkortsinnehavare kommer klara sig i framtiden.

Submitted by Gisely Teixeira (gisely.teixeira@uniceub.br) on 2018-06-16T14:53:52Z No. of bitstreams: 1 51600260.pdf: 1857956 bytes, checksum: 403a7d00d28ca8494344a3aef605dc5c (MD5) / Made available in DSpace on 2018-06-16T14:53:52Z (GMT). No. of bitstreams: 1 51600260.pdf: 1857956 bytes, checksum: 403a7d00d28ca8494344a3aef605dc5c (MD5) Previous issue date: 2018 / O concreto armado se tornou o material da construção civil mais utilizado em todo mundo, isso implica em estudos aprofundados para o entendimento do comportamento das estruturas concebidas com a aplicação deste material. Resultado desta preocupação foi a criação da Metodologia GDE, que possibilita a verificação do grau de deterioração de estruturas através de inspeções in-loco. Em posse desta ferramenta duas edificações de aproximadamente 43 anos de existência, situadas em uma organização militar do Exército Brasileiro no Distrito Federal, foram avaliadas com o objetivo de se verificar o grau de deterioração das duas edificações. Nesta avaliação foram inspecionados um total de 177 elementos estruturais com a confecção de croquis das edificações mapeando a incidência de cada tipo de patologia em cada edificação e por fim foi realizada uma comparação entre os estados de deterioração entre as edificações. Verificou-se que em uma das edificações a incidência de manifestações patológicas se deu de forma mais acentuada estando está em nível de deterioração médio, enquanto a segunda o nível de deterioração é baixo, esta diferença entre as duas edificações se justifica a diferente exposição à agentes externos a que os elementos estão expostos além disso tais anomalias foram motivadas pela falta de manutenção preventiva, impermeabilizações degradadas ou ausência da mesma e esbeltez excessiva dos elementos estruturais do Pavilhão de Comando.

Submitted by Gisely Teixeira (gisely.teixeira@uniceub.br) on 2018-06-16T14:53:52Z No. of bitstreams: 1 51600260.pdf: 1857956 bytes, checksum: 403a7d00d28ca8494344a3aef605dc5c (MD5) / Made available in DSpace on 2018-06-16T14:53:52Z (GMT). No. of bitstreams: 1 51600260.pdf: 1857956 bytes, checksum: 403a7d00d28ca8494344a3aef605dc5c (MD5) Previous issue date: 2018 / O concreto armado se tornou o material da construção civil mais utilizado em todo mundo, isso implica em estudos aprofundados para o entendimento do comportamento das estruturas concebidas com a aplicação deste material. Resultado desta preocupação foi a criação da Metodologia GDE, que possibilita a verificação do grau de deterioração de estruturas através de inspeções in-loco. Em posse desta ferramenta duas edificações de aproximadamente 43 anos de existência, situadas em uma organização militar do Exército Brasileiro no Distrito Federal, foram avaliadas com o objetivo de se verificar o grau de deterioração das duas edificações. Nesta avaliação foram inspecionados um total de 177 elementos estruturais com a confecção de croquis das edificações mapeando a incidência de cada tipo de patologia em cada edificação e por fim foi realizada uma comparação entre os estados de deterioração entre as edificações. Verificou-se que em uma das edificações a incidência de manifestações patológicas se deu de forma mais acentuada estando está em nível de deterioração médio, enquanto a segunda o nível de deterioração é baixo, esta diferença entre as duas edificações se justifica a diferente exposição à agentes externos a que os elementos estão expostos além disso tais anomalias foram motivadas pela falta de manutenção preventiva, impermeabilizações degradadas ou ausência da mesma e esbeltez excessiva dos elementos estruturais do Pavilhão de Comando.

Ce travail de thèse s'inscrit dans le cadre de la valorisation du CO2 par voie électrochimique. Il est consacré en grande partie à l'élaboration et l'étude physico-chimique d'électrodes à diffusion de gaz (GDE), dans le but de mieux comprendre les mécanismes et les paramètres déterminants pour l'électrocatalyse de la réduction du CO2 avec ce type d'électrodes poreuses. Cette étude est articulée autour de deux axes principaux, le premier concerne des catalyseurs métalliques et le second se focalise sur des catalyseurs moléculaires.Le premier axe est relatif à la préparation, la caractérisation et l'étude électrochimique de catalyseurs de Cu, Co, In, Zn, Bi, Fe et Pb supportés sur poudre de carbone poreux. La mise en œuvre de ces catalyseurs sous forme de GDE a été étudiée, ainsi que leur activité électrocatalytique vis-à-vis la réduction du CO2. En milieu aqueux, les GDE contenant de l'indium ont permis d'obtenir les meilleurs rendements faradiques pour l'électroréduction du CO2 en acide formique. Par comparaison avec une plaque métallique d'indium, les GDE-In/C montrent des performances catalytiques améliorées et une meilleure résistance aux impuretés de l'électrolyte. Nous avons montré, qu'en phase aqueuse, l'apport de CO2 gaz en continu à travers une GDE entraînait une amélioration de l'activité du catalyseur supporté. Ceci met en évidence l'intérêt d'utiliser des métaux sous forme de particules dispersées au sein d'une GDE plutôt que des électrodes métalliques massives.Le second axe de cette étude a fait appel à trois complexes dimère de ruthénium de formule générale [Ru(L)(CH3CN)(CO)2]2(PF6)2. L'étude des propriétés redox de ces précurseurs de catalyseurs contenant des ligands L (bipyridine) diversement substitués a permis de mettre en évidence la formation de polymères à liaisons Ru-Ru par électroréduction. Le ligand portant une fonction pyrrole permet, au préalable, la formation d'un film de polypyrrole conférant au catalyseur une meilleure stabilité et de meilleures performances catalytiques. Différentes stratégies d'immobilisation de ces complexes sur carbone poreux ont été utilisées pour obtenir des GDE modifiées. Cette étude a permis de mieux comprendre l'interaction entre le catalyseur moléculaire et le support lors de la réduction du CO2. Nous avons ainsi montré que l'activité électrocatalytique du catalyseur supporté sur GDE était maintenue en milieu aqueux.Parallèlement à ce travail fondamental, un pilote de laboratoire a été développé pour effectuer la réduction électrocatalytique du CO2 en phase gaz, afin de s'affranchir de limitations rencontrées en milieu aqueux, telles que la solubilité du CO2 et la séparation des produits de la réaction. Cette étude en cours de développement a permis d'identifier certains verrous, notamment la nature de la membrane échangeuse d'ions ainsi que la nature et la proportion du polymère électrolytique entrant dans la formulation de la couche catalytique. Ce travail apporte des connaissances fondamentales et des réponses concrètes qui permettront probablement qu'un tel procédé de valorisation du CO2 puisse constituer un jour un procédé viable à l'échelle industrielle. / This thesis concerns the valorization of CO2 by electrochemical means. It is largely devoted to the preparation and physico-chemical study of gas diffusion electrodes (GDE) in order to better understand the mechanisms and key parameters for electrocatalytic reduction of CO2 using this type of porous electrode. This study revolves around two main axes, the first is related to metal catalysts and the second is focused on molecular catalysts.The first axis deals with the preparation, characterization and electrochemical properties of Cu, Co, In, Zn, Bi, Pb and Fe catalysts supported on porous carbon powder. Their implementation to form GDE and their electrocatalytic activity toward CO2 reduction were studied. In aqueous medium, the GDE containing indium allowed obtaining the highest Faraday yields for electroreduction of CO2 to formic acid. In comparison with a metallic indium foil, the GDE-In/C showed improved catalytic performance and improved resistance to the electrolyte's impurities. We demonstrated that in the aqueous phase, a continuous flow of CO2 through a GDE resulted in an improved reactivity of the supported catalyst. This highlights the advantage of using dispersed metal particles on GDE rather than metal foil electrodes.The second axis of this study focuses on three dimeric ruthenium complexes with the general formula [Ru(L)(CH3CN)(CO)2]2(PF6)2. The study of the redox properties of these catalyst precursors containing variously substituted L (bipyridine) ligands, allowed the formation of polymer bonds of Ru-Ru by electroreduction to be demonstrated. The ligand with a pyrrole functional group allows for the prior formation of a polypyrrole film, conferring improved catalyst stability and enhancing the catalytic performance. Different ways of immobilizing the complex on porous carbon have been used to obtain modified GDE. This study provided insight into the interaction between the molecular catalyst and the catalyst carrier during the CO2 reduction. We have demonstrated that the electrocatalytic activity of the catalyst deposited on the GDE is maintained in an aqueous medium.Alongside this fundamental work, a laboratory pilot was developed to perform the electrocatalytic reduction of CO2 in the gas phase, in order to overcome limitations encountered in an aqueous medium, such as CO2 solubility and reaction products separation. This under development study has not only identified obstacles, including the nature of the ion exchange membrane, but has also identified the nature and proportion of the polymer electrolyte used in the formulation of the catalyst layer. This work has provided fundamental knowledge and concrete answers which probably allow one day that such a process as CO2 valorization may be viable on an industrial scale.

Water electrolysis is one of the first methods used to generate hydrogen and is thus not considered to be a new technology. With advances in proton exchange membrane technology and the global tendency to implement renewable energy, the technology of water electrolysis by implementation of proton exchange membrane as solid electrolyte has developed into a major field of research over the last decade. To gain an understanding of different components of the electrolyser it is best to conduct a performance analysis based on hydrogen production rates and polarisation curves. The study aim was to compare the technologies of membrane electrode assembly with gas diffusion electrode and the proton exchange membranes of Nafion® and polybenzimidazole in a commercial water electrolyser. To determine which of the components are best suited for the process a laboratory scale electrolyser was to be used to replicate the commercially scaled performance. The effect of feed water contaminants on electrolyser performance was also investigated by introducing iron and magnesium salt solutions and aqueous methanol solutions in the feed reservoir. Components to be tested included different PEM types as well as the base component on which the electrocatalyst layer is applied. The proton exchange membranes compared were standard Nafion® N117 and polybenzimidazole meta-sulfone sulfonated polyphenyl sulfone (PBI-sPSU). A laboratory scale electrolyser from Giner Electrochemical Systems was utilised where different components were tested and compared with one another. Experimental results with commercial membrane electrode assemblies and gas diffusion electrodes demonstrated the influence of temperature on electrolyser performance for the proton exchange membranes, where energy efficiency increased with temperature. The effect of pressure was insignificant over the selected pressure range. Comparison of membrane electrode assembly and gas diffusion electrode technologies showed enhanced performance from MEA technology, this was most likely due to superior electrocatalyst contact with the PEM. Results of synthesised Nafion® N117 and PBI-sPSU MEA showed increased performance for PBI-sPSU, but it was found to be more susceptible to damage under severe conditions. The effect of metal cations in the supply reservoir exhibited reduced energy efficiencies and increased specific energy consumption for the test duration. Treatment with sulphuric acid was found to partially restore membrane electrode assembly performance, though it is believed that permanent damage was inflicted on the membrane electrode assembly electrocatalyst. Use of aqueous methanol solutions were found to increase electrolyser performance. It was also found that aqueous methanol electrolysis occurs at lower current densities, whereas a combination of aqueous methanol and water electrolysis occurred at higher current densities depending on the concentration of methanol. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.

Water electrolysis is one of the first methods used to generate hydrogen and is thus not considered to be a new technology. With advances in proton exchange membrane technology and the global tendency to implement renewable energy, the technology of water electrolysis by implementation of proton exchange membrane as solid electrolyte has developed into a major field of research over the last decade. To gain an understanding of different components of the electrolyser it is best to conduct a performance analysis based on hydrogen production rates and polarisation curves. The study aim was to compare the technologies of membrane electrode assembly with gas diffusion electrode and the proton exchange membranes of Nafion® and polybenzimidazole in a commercial water electrolyser. To determine which of the components are best suited for the process a laboratory scale electrolyser was to be used to replicate the commercially scaled performance. The effect of feed water contaminants on electrolyser performance was also investigated by introducing iron and magnesium salt solutions and aqueous methanol solutions in the feed reservoir. Components to be tested included different PEM types as well as the base component on which the electrocatalyst layer is applied. The proton exchange membranes compared were standard Nafion® N117 and polybenzimidazole meta-sulfone sulfonated polyphenyl sulfone (PBI-sPSU). A laboratory scale electrolyser from Giner Electrochemical Systems was utilised where different components were tested and compared with one another. Experimental results with commercial membrane electrode assemblies and gas diffusion electrodes demonstrated the influence of temperature on electrolyser performance for the proton exchange membranes, where energy efficiency increased with temperature. The effect of pressure was insignificant over the selected pressure range. Comparison of membrane electrode assembly and gas diffusion electrode technologies showed enhanced performance from MEA technology, this was most likely due to superior electrocatalyst contact with the PEM. Results of synthesised Nafion® N117 and PBI-sPSU MEA showed increased performance for PBI-sPSU, but it was found to be more susceptible to damage under severe conditions. The effect of metal cations in the supply reservoir exhibited reduced energy efficiencies and increased specific energy consumption for the test duration. Treatment with sulphuric acid was found to partially restore membrane electrode assembly performance, though it is believed that permanent damage was inflicted on the membrane electrode assembly electrocatalyst. Use of aqueous methanol solutions were found to increase electrolyser performance. It was also found that aqueous methanol electrolysis occurs at lower current densities, whereas a combination of aqueous methanol and water electrolysis occurred at higher current densities depending on the concentration of methanol. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.

Made available in DSpace on 2016-07-27T14:20:42Z (GMT). No. of bitstreams: 1 Ednalva Macedo Nunes.pdf: 1233460 bytes, checksum: dd637af9ad4b475afef166d3c338027c (MD5) Previous issue date: 2015-03-16 / The school environment is a privileged place for the production and reproduction of knowledge and culture. Discrimination of gender, race and ethinicity, and sexual orientation, as well as sexist violence, are produced and reproduced in all spaces of brazilian social life. This research aims to analyze the meanings on gender and sexuality, in the school subjects "Gender" and "Sexuality ans sexual orientation", in the foruns of discussion of the continuing education course entitled "Gender and Diversity at Scholl" (GDE). Considering that the school is a privileged place for production and reproduction of knowledge, we took this course for analysis. The GDE, from the Federal University of Goiás (UFG), Regional Catalão, which is part of this research s corpus, is a reality thanks to the distance education (EaD), that enables education professionals to get to know and debate those themes, which cross the classroom daily, making it possible for the construction of a less sexist and more inclusive education. The research is fundamented on social constructionism, movement due to the emergency of new dialogs and new voices in response to the transformations that occurred in the world of ideas and prefessional practices. This research was conducted in the Moodle plataform, hosted in the UFG campus Catalão and has documents of public domain and the transcripts from discussion foruns of the subjcts "Gender " and "Sexuality and sexual orientation", from the GDE course as its source of information. The analysis reveals that the meanings assigned to these concepts still carry a load of prejudice and stereotypes present in people s daily life, and therefore, considered controversial. / O espaço escolar é um lugar privilegiado para a produção e reprodução de saberes e de cultura. As discriminações de gênero, étnico-racial e de orientação sexual, como também a violência sexista, são produzidas e reproduzidas em todos os espaços da vida social brasileira. Esta pesquisa tem por objetivo analisar os sentidos sobre gênero e sexualidade, nas disciplinas Gênero e Sexualidade e Orientação Sexual , nos fóruns de discussão do curso de formação continuada à distância intitulado Gênero e Diversidade na Escola (GDE). Considerando que, a escola é um lugar privilegiado de produção e reprodução do conhecimento, tomamos este curso para análise. O curso GDE da UFG-Regional Catalão, que faz parte do corpus desta pesquisa, é uma realidade graças a EaD, pois oportuniza aos profissionais da educação conhecer e debater esses temas, os quais atravessam a sala de aula diariamente, possibilitando a construção de uma educação menos sexista e inclusiva. A pesquisa tem como fundamentação teórica o construcionismo social, movimento decorrente da emergência de novos diálogos e novas vozes em resposta às transformações ocorridas no mundo das ideias e das práticas profissionais. A pesquisa foi realizada na plataforma moodle, hospedada na UFG Regional Catalão, tendo como fontes de informação documentos de domínio público e os fóruns de discussão do curso GDE nas disciplinas Gênero e Sexualidade e Orientação sexual . A análise revela que os sentidos atribuídos a esses conceitos ainda carregam uma carga de preconceitos e estereótipos presentes no cotidiano das pessoas, sendo considerados polêmicos.

In recent years an emphasis has been placed on the development of alternative and clean energy sources to reduce the global use of fossil fuels. One of these alternatives entails the use of H2 as an energy carrier, which can be obtained amongst others using thermochemical processes, for example the hybrid sulphur process (HyS). The HyS process is based on the thermal decomposition of sulphuric acid into water, sulphur dioxide and oxygen. The subsequent chemical conversion of the sulphur dioxide saturated water back to sulphuric acid and hydrogen is achieved in an electrolyser using a platinum coated proton exchange membrane. This depolarised electrolysis requires a theoretical voltage of only 0.158 V compared to water electrolysis requiring approximately 1.23 V. One of the steps in the development of this technology at the North-West University, entailed the establishment of the platinum coating technology which entailed two steps; firstly using newly obtained equipment to manufacture the membrane electro catalyst assemblies (MEA’s) and gas diffusion electrodes (GDE’s) and secondly to test these MEA’s and GDE’s using sulphur dioxide depolarized electrolysis by comparing the manufactured MEA’s and GDE’s to commercially available MEA’s and GDE’s. Different MEA’s and GDE’s were manufactured using both a screen printing (for the microporous layer deposition) and a spraying technique. The catalyst loadings were varied as well as the type and thickness of the proton exchange membranes used. The proton exchange membranes that were included in this study were Nafion 117®, sPSU-PBIOO and SfS-PBIOO membranes whereas the gas diffusion layer consisted of carbon paper with varying thicknesses (EC-TP01-030 – 0.11 mm and EC-TP01-060 – 0.19mm). MEA and GDE were prepared by first preparing an ink that was used both for MEA and GDE spraying. The MEA’s were prepared by spraying various catalyst coatings onto the proton exchange membranes containing 0.3, 0.6 and 0.9 mg/cm2 platinum respectively. The GDE’s were first coated by a micro porous carbon layer using the screen printing technique in order to attain a suitable surface for catalyst deposition. Using the spraying technique GDE’s containing 0.3, 0.6, 0.9 mg/cm2 platinum were prepared. After SEM analysis, the MEA’s and GDE’s performance was measured using SO2 depolarized electrolysis. From the electrolysis experiments, the voltage vs. current density generated during operation, the hydrogen production, the sulphuric acid generation and the hydrogen production efficiency was obtained. From the results it became clear that while the catalyst loading had little effect on performance there were a number of factors that did have a significant influence. These included the type of proton exchange membrane, the membrane thickness and whether the catalyst coating was applied to the proton exchange membrane (MEA) or to the gas diffusion layer (GDE). During SO2 depolarized electrolysis VI curves were generated which gave an indication of the performance of the GDE’s and MEA’s. The best preforming GDE was GDE-3 (0.46V @ 320 mA/cm2), which included a GDE EC-TP01-060, while the best preforming MEA’s were NAF-4 (0.69V @ 320mA/cm2) consisting of a Nafion117 based MEA and PBI-1 (0.43V @ 320mA/cm2) made from a sPSU-PBIOO blended membrane. During hydrogen production it became clear that the GDE’s produced the most hydrogen (best was GDE-02 a in house manufactured GDE yielding 67.3 mL/min @ 0.8V), followed by the Nafion® MEA’s (best was NAF-4 a commercial MEA yielding 57.61 mL/min @ 0.74V) and the PBI based MEA’s. , (best was PBI-2 with 67.11 mL/min @ 0.88V). Due to the small amounts of acid produced and the SO2 crossover, a significant error margin was observed when measuring the amount of sulphuric acid produced. Nonetheless, a direct correlation could still be seen between the acid and the hydrogen production as had been expected from literature. The highest sulphuric acid concentrations produced using the tested GDE’s and MEA’s from this study were the in-house manufactured GDE-01 (3.572mol/L @ 0.8V), the commercial NAF-4 (4.456mol/L @ 0.64V) and the in-house manufactured PBI-2 (3.344mol/L @ 0.8V). The overall efficiency of the GDE’s were similar, ranging from less than 10% at low voltages (± 0.6V) increasing to approximately 60% at ± 0.8V. For the MEA’s larger variation was observed with NAF-4 reaching efficiencies of nearly 80% at 0.7V. In terms of consistency of performance it was shown that the Nafion MEA’s preformed most consistently followed by the GDE’s and lastly the PBI based MEA’s which for the PBI based membranes can probably be ascribed to the significant difference in thickness of the thin PBI vs. the Nafion based membranes. In summary the study has shown the results between the commercially obtained and the in-house manufactured GDE’s and MEA’s were comparable confirming the suitability of the coating techniques evaluated in this study. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2014

In recent years an emphasis has been placed on the development of alternative and clean energy sources to reduce the global use of fossil fuels. One of these alternatives entails the use of H2 as an energy carrier, which can be obtained amongst others using thermochemical processes, for example the hybrid sulphur process (HyS). The HyS process is based on the thermal decomposition of sulphuric acid into water, sulphur dioxide and oxygen. The subsequent chemical conversion of the sulphur dioxide saturated water back to sulphuric acid and hydrogen is achieved in an electrolyser using a platinum coated proton exchange membrane. This depolarised electrolysis requires a theoretical voltage of only 0.158 V compared to water electrolysis requiring approximately 1.23 V. One of the steps in the development of this technology at the North-West University, entailed the establishment of the platinum coating technology which entailed two steps; firstly using newly obtained equipment to manufacture the membrane electro catalyst assemblies (MEA’s) and gas diffusion electrodes (GDE’s) and secondly to test these MEA’s and GDE’s using sulphur dioxide depolarized electrolysis by comparing the manufactured MEA’s and GDE’s to commercially available MEA’s and GDE’s. Different MEA’s and GDE’s were manufactured using both a screen printing (for the microporous layer deposition) and a spraying technique. The catalyst loadings were varied as well as the type and thickness of the proton exchange membranes used. The proton exchange membranes that were included in this study were Nafion 117®, sPSU-PBIOO and SfS-PBIOO membranes whereas the gas diffusion layer consisted of carbon paper with varying thicknesses (EC-TP01-030 – 0.11 mm and EC-TP01-060 – 0.19mm). MEA and GDE were prepared by first preparing an ink that was used both for MEA and GDE spraying. The MEA’s were prepared by spraying various catalyst coatings onto the proton exchange membranes containing 0.3, 0.6 and 0.9 mg/cm2 platinum respectively. The GDE’s were first coated by a micro porous carbon layer using the screen printing technique in order to attain a suitable surface for catalyst deposition. Using the spraying technique GDE’s containing 0.3, 0.6, 0.9 mg/cm2 platinum were prepared. After SEM analysis, the MEA’s and GDE’s performance was measured using SO2 depolarized electrolysis. From the electrolysis experiments, the voltage vs. current density generated during operation, the hydrogen production, the sulphuric acid generation and the hydrogen production efficiency was obtained. From the results it became clear that while the catalyst loading had little effect on performance there were a number of factors that did have a significant influence. These included the type of proton exchange membrane, the membrane thickness and whether the catalyst coating was applied to the proton exchange membrane (MEA) or to the gas diffusion layer (GDE). During SO2 depolarized electrolysis VI curves were generated which gave an indication of the performance of the GDE’s and MEA’s. The best preforming GDE was GDE-3 (0.46V @ 320 mA/cm2), which included a GDE EC-TP01-060, while the best preforming MEA’s were NAF-4 (0.69V @ 320mA/cm2) consisting of a Nafion117 based MEA and PBI-1 (0.43V @ 320mA/cm2) made from a sPSU-PBIOO blended membrane. During hydrogen production it became clear that the GDE’s produced the most hydrogen (best was GDE-02 a in house manufactured GDE yielding 67.3 mL/min @ 0.8V), followed by the Nafion® MEA’s (best was NAF-4 a commercial MEA yielding 57.61 mL/min @ 0.74V) and the PBI based MEA’s. , (best was PBI-2 with 67.11 mL/min @ 0.88V). Due to the small amounts of acid produced and the SO2 crossover, a significant error margin was observed when measuring the amount of sulphuric acid produced. Nonetheless, a direct correlation could still be seen between the acid and the hydrogen production as had been expected from literature. The highest sulphuric acid concentrations produced using the tested GDE’s and MEA’s from this study were the in-house manufactured GDE-01 (3.572mol/L @ 0.8V), the commercial NAF-4 (4.456mol/L @ 0.64V) and the in-house manufactured PBI-2 (3.344mol/L @ 0.8V). The overall efficiency of the GDE’s were similar, ranging from less than 10% at low voltages (± 0.6V) increasing to approximately 60% at ± 0.8V. For the MEA’s larger variation was observed with NAF-4 reaching efficiencies of nearly 80% at 0.7V. In terms of consistency of performance it was shown that the Nafion MEA’s preformed most consistently followed by the GDE’s and lastly the PBI based MEA’s which for the PBI based membranes can probably be ascribed to the significant difference in thickness of the thin PBI vs. the Nafion based membranes. In summary the study has shown the results between the commercially obtained and the in-house manufactured GDE’s and MEA’s were comparable confirming the suitability of the coating techniques evaluated in this study. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2014

Membranas hidrocarbônicas não fluoradas têm sido desenvolvidas para uso em substituição as membranas fluoradas (Nafion®) em células a combustível de eletrólito polimérico (PEMFC), ou em temperaturas superiores a 80 °C, ou em células com adição direta de álcool. Este trabalho teve como objetivo avaliar o desempenho de membranas hidrocarbônicas catiônicas, desenvolvidas para uso em célula a combustível alimentada com etanol (DEFC), e de camadas de difusão gasosa (GDL – Gas Difusion Layer) e eletrodos (GDE – Gas Difusion electrode) preparados para uso com as mesmas. Duas membranas hidrocarbônicas (E-750 e P-730) da empresa FuMATech®/GR foram avaliadas quanto à capacidade de troca iônica e grau de inchamento em água/etanol, quanto a composição química, morfologia, comportamento térmico e visoelástico e condutividade por impedância. As GDLs foram preparadas a partir de uma emulsão aquosa de Teflon® e pó de carbono Vulcan XC-72R®, com e sem agente emulsificante (resina sulfonada), dispersa em ambas as faces do tecido de carbono pelo método de aspersão. Os GDEs foram preparados pela deposição de emulsão catalítica de diferentes eletrocatalisadores sobre as respectivas GDLs do ânodo e catodo. Os GDEs anódico e catódico foram preparados com 1 mg.cm-2 do eletrocatalisador de PtSn/C 20% (75:15) e de Pt/C (20:80), respectivamente, e caracterizados por MEV-EDS. As características fisico-químicas das membranas hidrocarbônicas foram similares às apresentadas pela membrana Nafion®. O desempenho do protótipo de célula unitária DEFC com as membranas FuMATech® foi inferior ao obtido com a membrana Nafion® usando-se GDE comercial. Por outro lado, ensaios com a membrana Nafion® utilizando-se os eletrodos preparados neste trabalho e eletrodos comerciais apresentaram valores de potencial similares. / Non-fluorinated hydrocarbon cationic membranes have been developed for use instead of Nafion® in Polymer Electrolyte Membrane Fuel Cells (PEMFCs), or at higher temperatures than 80 ºC, or in fuel cells fed with alcohol. The aim of this work was to evaluate the performance of commercial non-fluorinated hydrocarbon cationic membranes with potential use in direct ethanol fuel cell (DEFC), and also evaluate the Gas Difusion Layer (GDL) and Gas Difusion electrode (GDE) prepared for use with them. Two hydrocarbon membranes (E-750 and P-730) produced by FuMATech®/GR were analyzed according to their ion exchange capacity, water uptake in water/alcohol solution, morphology, chemical composition, thermal and viscoelastic behaviour, and conductivity by impedance. The GDLs were prepared by spraying an aqueous emulsion of Vulcan carbon/Teflon®, with and without emulsifier agent (sulfonated hydrocarbon resin), in both sides of a carbon fabric. The electrodes were prepared by the respective deposition of the electrocatalysts emulsions on the cathode and anode GDLs. The anodic and cathodic GDEs were prepared with 1 mg.cm-2 of the electrocatalyst of PtSn/C 20% (75:15) and of Pt/C (20:80), respectively, which were characterized by SEM-EDS. The physicochemical properties of the hydrocarbon membranes were similar to the Nafion® membrane ones. The potential values obtained in a DEFC prototype unit cell with FuMATech® membranes were lower than those with Nafion-117 membrane. On the other hand, the performance of the DEFC prototype with Nafion-117 membrane was the same if used GDEs commercial or here prepared.