Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2014-10-27T17:17:05Z No. of bitstreams: 1 ElecyTese corrigida 30 07 14.pdf: 1118101 bytes, checksum: fcfaf3d2c9511c09fdcaefb24555ec74 (MD5) / Approved for entry into archive by Ana Hilda Fonseca (anahilda@ufba.br) on 2014-10-29T15:53:07Z (GMT) No. of bitstreams: 1 ElecyTese corrigida 30 07 14.pdf: 1118101 bytes, checksum: fcfaf3d2c9511c09fdcaefb24555ec74 (MD5) / Made available in DSpace on 2014-10-29T15:53:08Z (GMT). No. of bitstreams: 1 ElecyTese corrigida 30 07 14.pdf: 1118101 bytes, checksum: fcfaf3d2c9511c09fdcaefb24555ec74 (MD5) / FAPESB / A mandioca ( Manihot esculenta Crantz) é uma plan ta de origem da América do Sul, tendo como produto principal a farinha de mandioca, que é um alimento rico em carboidratos, fibras, proteína, Ca, P, Na, K e Fe , entre outros. A prod ução de farinha corresponde a 22 % da produção nacional de mandioca e é pro duzida por pequenos produtores. Sendo assim, é oportuno o desenvolvimento de estudos que visam à caracterização da farinha de mandioca quanto à sua composição para se ter um controle de qualidade adequado para consumo. O objetivo deste trabalho foi propor estratégias para a caracterização da farinha de mandioca produzida no E stado da Bahia em função das concentrações de Al, As, Ba, Br, Ca, Cd, Cl, Cu, Fe, I, K, Mg, Mn, Na, Ni, P, Pb e Zn. Em uma primeira etapa foram comparados três procedimentos para o prep aro das amostras : (1) por via úmida com aquecimen to condutivo em bloco digestor, (2) assistido por radiação micro - ondas e (3) por via seca. Os elementos foram determinados por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES). Fo i recomendado o procedimento assistido por radiação micro - ondas para determinação da composição elementar nas 24 amostras de farinha de mandioca adquiridas em diferentes localidades do estado da Bahia devido a sua maior eficiência e menor possibilidade de contaminação. Na segunda etapa foi proposto um procedimento para determinação de As, Pb, Cd e Se empregando espectrometria de absorção atômica com atomização eletrotérmica e detecção simultânea, utilizando a mistura de W e Rh como modificador. Foi possível determinar Pb e Cd em todas as amostras e os resultados obtidos indicaram para concentrações abaixo dos limites estabelecidos pela legislação. Na etapa final foram desenvolvidos estudos preliminares para a determinação de Cl, Br e I por ICP OES. / Cassava (Manihot esculenta Crantz) is a plant of South America, with the main product of cassava flour, which is a food rich in carbohyd rates, fiber, protein, Ca, P, Na, K and Fe. The production flour corresponds 22.1% of national production of cassava and is produced by small producers. Thus, it is desirable to develop studies aimed at characterization of cassava flour in their compositio n to have a quality control suitable for consumption. The objective of this study was to propose strategies for the characterization of cassava flour produced in the state of Bahia in the concentrations of Al, As, Ba, Br, Ca, Cd, Cl, Cu, Fe, I, K, Mg, Mn,N a, Ni, P, Pb and Zn. In a first step we compared three procedures for the preparation: (1) procedures using acids with heat conductive in block digester and (2) assisted by microwave and (3) procedure by calcination. The elements were determined by optical emission spectrometry with inductively coupled plasma (ICP OES). It was recommended the procedure assisted by microwave radiation to determine the elemental composition in 24 samples of cassava flour acquired in different localities of Bahia state conside ring its greater efficiency and less chance of contamination. In the second step was proposed a procedure for determination of As, Pb, Cd and Se using atomic absorption spectrometry with electrothermal atomization and simultaneous detection using a mixture of Rh and W as chemistry modifier. Lead was determined in all samples and the results indicated concentrations below the limits established by law. In the final stage preliminary studies have been developed for the determination of Cl, Br and I by ICP OES . Further studies should be developed to a greater number of samples in order to establish a more complete profile and contribute to the Table of Food Composition at the regional level

A formação e propagação de fissuras é um fenômeno observado em diversos materiais utilizados na engenharia, como concreto, metais, cerâmicas e rochas. Tendo em vista a grande influência que fissuras têm no comportamento global da estrutura o objetivo deste trabalho consiste na implementação de um modelo de fissura com descontinuidades fortes incorporadas a fim de analisar o processo de fratura em materiais quase-frágeis. A descontinuidade no campo de deslocamentos (descontinuidade forte) é representada através da introdução de graus de liberdade adicionais no interior do elemento finito, sendo esta abordagem denominada enriquecimento elementar (E-FEM). Nestes modelos a fissura pode se propagar em qualquer direção dentro do elemento finito, evitando a necessidade de redefinição da malha em cada etapa, além de fornecer resultados relativamente independentes da malha de elementos finitos utilizada. Por serem internos a cada elemento finito, os graus de liberdade adicionais podem ser eliminados da solução global por condensação estática. Desta forma as descontinuidades são definidas em nível de elemento e o modelo pode ser facilmente implementado em códigos computacionais existentes. O modelo implementado foi proposto por Dvorkin, Cuitiño e Gioia (1990), o qual pertence à classe de modelos com formulação assimétrica estaticamente e cinematicamente consistente (SKON). Esta formulação é caracterizada por garantir o movimento de corpo rígido entre as partes do elemento além de assegurar a continuidade de tensões na linha de fissura, resultando numa matriz de rigidez assimétrica. Diferentes relações constitutivas podem ser utilizadas para descrever o comportamento das regiões com e sem fissura. Portanto, para a região não fissurada, utilizouse um modelo constitutivo elástico linear e para a região fissurada foi analisada a performance de dois modelos constitutivos distintos: linear e exponencial. A capacidade de representar o comportamento de elementos estruturais fissurados foi ilustrada através de exemplos de tração e flexão comparados com outros modelos de fissura existentes e com resultados experimentais. Em relação aos modelos constitutivos para a linha da fissura, o modelo linear não se mostrou adequado por superestimar as tensões de pico além de apresentar um ramo de amolecimento mais frágil. Já o modelo exponencial mostrou-se bastante eficiente representando de forma correta o comportamento de materiais quase-frágeis. / The formation and propagation of cracks is a phenomenon observed in many materials used in engineering, such as concrete, metals, ceramics and rocks. In view of the influence of cracks in the global behavior of the structure, the aim of this work is the implementation of an embedded strong discontinuity model in order to analyze the fracture process in quasi-brittle materials. The discontinuity in the displacement field (strong discontinuity) is represented by the introduction of additional degrees of freedom within the finite element. This approach is called elemental enrichment (E-FEM). The embedded models allow the propagation of crack in any direction within the finite element, avoiding the need of remeshing and providing objective results (mesh independent). The additional degrees of freedom are introduced into the finite element, then these degrees can be eliminated from the global solution by static condensation and the model can be easily implemented in existent computational codes. The model used here was proposed by Dvorkin, Cuitiño and Gioia (1990), which belongs to the statically and kinematically optimal non-symmetric (SKON) formulation. In this formulation, the kinematics that allows for relative rigid body motion and the enforcement of the traction continuity are introduced at element level, resulting a non-symmetric formulation. Different constitutive relations can be used to describe the behavior of the zones with and without cracks. For the zone without cracks it was used a linear elastic model and for the cracked zone it was analyzed the behavior of two different constitutive models: linear and exponential. The ability of the model to represent the behavior of cracked structural elements was illustrated by bending and tensile tests and the results were compared with numerical and experimental data. Regarding the constitutive models for the fracture zone, it was concluded that the linear model was not suitable because it overestimated the maximum stress and promoted a britller softening. In contrast, the exponential model proved to be very efficient to represent the behavior of quasi-brittle materials.

No presente trabalho foram desenvolvidos métodos para a determinação de Al, B, Ba, Ca, Co, Cu, Cr, Fe, K, Li, Mg, Mn, P, S, Si, Sn, Sr, Ti, V e Zn por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e As, Cd, Pb e Se por espectrometria de absorção atômica com forno de grafite e detecção simultânea (SIMAAS) em polpa de graviola (Annona muticata L.). A determinação de proteínas bem como a estimativa da presença de Fe, Cu, Mn e Zn a elas associados também foram investigados. Para as determinações elementares foi utilizada polpa de graviola, seca em estufa a 50° C, digeridas com mistura oxidante diluída (2 mL HNO3 + 1 mL H2O2 + 3 mL H2O) e aquecimento em forno de micro-ondas com frasco fechado. A avaliação da exatidão dos métodos foi feita a partir da análise de material de referência certificado (Citrus Leaves SRM 1572, NIST) e os resultados concordaram, para maioria dos elementos, em 95% como intervalo de confiança, quando aplicado o teste t-Student. A polpa também foi submetida a diferentes pré-tratamentos: 1) secagem por liofilização e moagem em moinho criogênico; 2) homogeneização da polpa in natura em moinho de facas; e 3) secagem em estufa a 50 °C e moagem em almofariz e pistilo. Nessa etapa, o objetivo foi avaliar a influência dos procedimentos de pré-tratamento nas extrações de proteínas. Massas de amostra (~5 g), após extração lipídica, foram submetidas à agitação (1 h) com 0,5 mol L-1 NaOH, tampão Tris-HCl (pH 7,5), 0,5 mol L-1 HCl e tampão CO32-/HCO31- (pH 10) para extração de proteínas. Os extratos foram analisadas por ICP OES para determinação de Cu, Fe, Mn e Zn e proteínas pelo método de Bradford. Alíquotas dos extratos foram submetidas à etapa de limpeza (clean up) utilizando acetona em banho de gelo, 0,5 mol L-1 HCl e 20% m v-1 de TCA para precipitação de proteínas. Somente acetona em banho de gelo foi eficiente na precipitação das proteínas. Os precipitados foram redissolvidos em tampão Tris-HCl e submetidos a separação por cromatografia de exclusão por tamanho e detecção por espectrofotometria UV (SEC-UV), a 280 nm. As proteínas totais nas amostras foram estimadas por análise elementar (CHN) e, em solução, pelo método de Bradford. Independente da solução extratora utilizada, o processo de liofilização e moagem criogênica foi o que proporcionou maior quantidade de proteínas extraídas. Porém, após a precipitação com 80 % v v-1 de acetona, maior quantidade de proteínas foram precipitadas da amostra in natura, indicando possíveis alterações durante a liofilização e secagem. Em todos os extratos submetidos a análises por SEC-UV foi observado maior quantidade de compostos de baixo peso molecular (< 6,5 kDa). Melhor eficiência de extração de proteínas e dos elementos Cu, Fe, Mn e Zn foi observada na extração com NaOH. Maiores concentrações dos elementos extraídos foram encontradas nas amostras in natura e menores nas amostras secas em estufa com moagem em almofariz e pistilo. / In this work methods for the determination of Al, B, Ba, Ca, Co, Cu, Cr, Fe, K, Li, Mg, Mn, P, S, Si, Sn, Sr, Ti, V and Zn by inductively coupled plasma optical emission spectrometry (ICP OES) and As, Cd, Pb e Se by simultaneous graphite furnace atomic absorption spectrometry (SIMAAS) in graviola pulp (Annona Muricata L.) were developed. The determination of proteins and the possible presence of Fe, Cu, Mn and Zn associated to them were also investigated. For elements determination, graviola pulp was dry in wood stove at 50%C and digested using diluted oxidant mixture (2 mL HNO3 + 1 mL H2O2 + 3 mL H2O) in closed-vessel microwave oven. The accuracy and precision of the methods were done by certified reference material analysis (Citrus Leaves SRM 1572, NIST), and the obtained results were in accordance at 95%, according Student-t test. The graviola pulp was also submitted to different pretreatments: 1) lyophilization and cryogenic grinding; 2) homogenization of the in natura sample in a knife mill; and 3) drying in wood stove at 50%C and grinding in a mortar. The objective of this step was to evaluate the influence of sample pretreatment on the protein extractions. After lipid extraction, sample masses (~5 g) were shacked (1 h) with 0.5 mol L-1 NaOH, Tris-HCl buffer (pH 7.5), 0.5 mol L-1 HCl and CO32-/HCO31- buffer (pH 10) for protein extraction. The extractants solutions were analyzed for Cu, Fe, Mn and Zn determinations by ICP OES and for protein determinations by Bradford method. A clean up step, using acetone in ice-bath, 0.5 mol L-1 of HCl and 20% m v-1 of TCA was used for protein precipitation. In this way, only acetone in ice-bath was efficient for precipitation. After that, precipitates were dissolved in Tris-HCl buffer and analyzed by size exclusion chromatography with UV detection (SEC-UV), at 280 nm. Total protein contents in the sample and in the extracting solutions were determined by elemental analysis (CHN) and Bradford method, respectively. For all extracting solutions, the lyophylization and cryogenic grinding procedure showed the best efficiency for proteins extraction. However, after precipitation with acetone 80 v v-1, higher amount of proteins were observed for in natura sample, indicating some structure protein modification during the lyophylization or drying pretreatment steps. In general, low molecular weight compounds (< 6,5 kDa) were observed for all extracting solutions. The NaOH extractor showed much better efficiency for proteins and Cu, Fe, Mn and Zn extraction. Higher concentration of the extracting elements were found for in natura samples and lower for drying in wood stove at 50%C and grinding in a mortar.

Com o aumento das exigências regulatórias e estabelecimento de limites mais restritos para impurezas elementares em fármacos e excipientes usados em formulações farmacêuticas, ocorreu uma busca por técnicas analíticas capazes de quantificar elementos em níveis traço e assegurar a qualidade e a segurança dos medicamentos. A espectrometria de massas com plasma acoplado indutivamente (ICP-MS) é uma técnica multielementar, que apresenta alta sensibilidade e é empregada com eficiência na análise de elementos traço em diferentes matrizes. O ICP-MS, acoplado a um sistema separador como o cromatógrafo líquido de alta eficiência (HPLC), possibilita a especiação de elementos químicos, o que é importante, pois a toxicidade pode estar diretamente ligada à forma química do elemento, como ocorre para o Hg e As. Neste sentido, os objetivos deste trabalho foram desenvolver e validar um método de análise simples, rápido e com alta sensibilidade, para determinação de 15 impurezas elementares: As, Cd, Cr, Cu, Ni, Pb, V, Ir, Pd, Pt, Rh, Ru, Hg, Os e Mo, em diferentes fármacos e excipientes, em níveis que atendam aos novos critérios estabelecidos pelos órgãos regulatórios, avaliar a utilização da cela de reação dinâmica (DRC) para eliminação de interferências espectrais na determinação de As, Cr e V, realizar a especiação de As e Hg, e aplicar esta metodologia para análise de diversas amostras comprovando sua robustez, versatilidade e vantagens para utilização em rotina. Foram avaliadas cinco estratégias de preparo de amostra: digestão em micro-ondas sistema fechado e digestão em micro-ondas - sistema aberto, digestão em banho-maria, diluição direta em meio ácido e extração utilizando ponteira de ultrassom. Através de ensaios de recuperação e materiais de referência certificados, os melhores resultados (84 a 101%) foram obtidos com a digestão das amostras em sistema fechado de micro-ondas e extração por ponteira de ultrassom. Os limites de detecção variaram entre 0,001 ng g-1 (103Rh) e 0,083 ng g-1 (75As). Em seguida, a metodologia analítica foi empregada para determinação dos elementos em estudo em 74 amostras de fármacos e excipientes. O elemento mais frequentemente encontrado foi o Cu, seguido por Cr, Mo, Ni, Pd e V. Já os elementos químicos Ir, Pt, Os e Ru não foram detectados. Cabe destacar que as concentrações de Pd, Rh, As, Cd, Cr, Cu, Ni, V e Mo encontraram-se acima do limite preconizado pela farmacopeia americana em algumas amostras. A análise por especiação química de As mostrou que as amostras possuíam apenas as formas inorgânicas e mais tóxicas. Em relação ao Hg, apenas uma amostra apresentou níveis detectáveis deste elemento, mas a concentração estava abaixo do limite estabelecido pela farmacopeia americana. / Due to quality and safety reasons, regulatory requirements and establishment of more restricted limits for elemental impurities in drugs and excipients are increasing. These regulations promoted a search for simple and robust analytical techniques for quantification of trace elements. Inductively coupled plasma mass spectrometry (ICP-MS) is an attractive technique for this purpose, presenting multielement and high sensitivity capabilities. ICP-MS can be hyphenated to separation techniques such as high-performance liquid chromatography (HPLC), enabling chemical speciation analysis. Speciation analysis may reveal the chemical form of the element that may be more directly related to the toxicity. In this sense, the objectives of this work were to develop and validate a simple, fast and highly sensitive method for the determination of 15 elemental impurities: As, Cd, Cr, Cu, Ni, Pb, V, Ir, Pd, Rh, Ru, Hg, Os and Mo, in different drugs and excipients, at levels that meet the new criteria established by the regulatory agencies. We also evaluated the use of the dynamic reaction cell (DRC) to eliminate spectral interferences for As, Cr And V. Finally, for As and Hg, speciation methods were applied. All analysis were performed focusing on robustness, versatility and sample high-throughput. We tested five sample preparation strategies: closed microwave system digestion, microwave digestion - open system, water bath digestion, direct acid dilution and ultrasound probe extraction. Recovery studies in ordinary samples and reference certified materials were observed with the closed microwave digestion system and ultrasound probe extraction (84 and 101%). Detection limits ranged from 0.001 ng g-1 for 103Rh to 0.083 ng g-1 for 75As. The analytical methodology was then applied for the determination of the elements in study in 74 samples of drugs and excipients. The most frequently found element was Cu, followed by Cr, Mo, Ni, Pd and V. The chemical elements Ir, Pt, Os and Ru were not detected. It should be mention that the concentrations of Pd, Rh, As, Cd, Cr, Cu, Ni, V and Mo were above the limit recommended by the American pharmacopeia in some samples. Only inorganic arsenic (most toxic forms) was found in samples by applying speciation analysis. Regarding Hg, only one sample had detectable levels of this element, but the concentration was below the limit established by the American pharmacopeia

Neste trabalho foi feita uma caracterização do material particulado coletado no Centro de Capacitação e Pesquisa em Meio Ambiente (CEPEMA) localizado na cidade de Cubatão, na Baixada Santista. As coletas ocorreram entre março de 2009 e novembro de 2010, utilizando amostradores de material particulado fino, grosso e inalável (Mini-Vol) e um impactador em cascata (MOUDI) para as várias frações do material particulado, durante oito campanhas experimentais. Foi realizada uma caracterização climatológica com os dados de temperatura, pressão atmosférica, umidade relativa, velocidade e direção do vento das estações da CETESB em Cubatão: Centro (10 anos), Vila Parisi (10 anos) e Vale do Mogi (4 anos). Os dados de chuva foram obtidos da Defesa Civil para a cidade de Santos. A maior parte das coletas de 2009 ocorreu em períodos em que houve precipitação, ao passo que as coletas de 2010 foram amostradas em períodos mais secos. O material particulado fino (MPF) teve concentrações médias de: 15,7 e 18,8 g m-3 em 2009 e 2010, respectivamente, quando coletado pelo MOUDI; e 15,8 e 23,6 g m-3, quando coletado pelo Mini-Vol. O material particulado grosso (MPG) teve concentrações médias de: 11,4 e 14,1 g m-3 em 2009 e 2010, respectivamente, quando coletado pelo MOUDI; e 18,9 e 13,4 g m-3, quando coletado pelo Mini-Vol. As análises de refletância mostraram que o Black Carbon está quase totalmente no MPF, chegando a 15% (20%) da massa do MPF quando coletado pelo MOUDI (Mini-Vol). Os íons dominantes são sulfato (SO42), nitrato (NO3), sódio (Na+), amônio (NH4+) e cálcio (Ca2+) e os elementos dominantes são enxofre (S), silício (Si) e ferro (Fe). As distribuições de tamanho mostram uma moda de nucleação bastante pronunciada para o S, K, Cl e P, indicando a contribuição de fontes antropogênicas e formação secundária do aerossol. As maiores concentrações de Si, Cl, Ca, Fe, Ca2+, NO3 e Na+ se encontram no MPG. Para o Cl e Na+, foram encontradas maiores concentrações nas amostras diurnas com vento do quadrante sul-sudoeste na estação do Centro, demonstrando a contribuição marinha. / This work evaluated the particulate matter (PM) collected at the Environmental Research and Training Center (CEPEMA) located in Cubatão City. Sampling was made between 2009, March and 2010, November for fine, coarse and inhalable aerosol (Mini-Vol) and for the various fractions of PM with a cascade impactor (MOUDI) during eight experimental campaigns. A climatological study was performed for temperature, pressure, relative humidity, wind speed and direction using data from CETESB stations: Centro (10 years), Vila Parisi (10 years) and Vale do Mogi (4 years). Precipitation data was obtained from the Civil Defense for the city of Santos. Most samplings made during 2009 were concomitant with rainy days, whereas 2010 samplings were made in drier periods. Fine particulate matter (FPM) had average concentrations of: 15.7 and 18.8 g m-3 in 2009 and 2010, respectively, with MOUDI and 15.8 and 23.6 g m-3, with Mini-Vol. Coarse Particulate Matter (CPM) had average concentrations of: 11.4 and 14.1 g m-3 in 2009 and 2010, respectively, with MOUDI, and 18.9 and 13.4 g m-3, with Mini-Vol. Reflectance analysis showed that the Black Carbon is almost completely in the FPM, reaching up to 15 % (20 %) of the FPM mass when sampled with MOUDI (Mini-Vol). Dominant ions are sulfate (SO42-), nitrate (NO3-), sodium (Na+), ammonium (NH4+) and calcium (Ca2+) and the dominant elements are sulfur (S), silicon (Si) and iron (Fe). The size distributions shows a very pronounced nucleation mode for the S, K, P and Cl, indicating the contribution of anthropogenic sources and secondary aerosol formation. The highest concentrations of Si, Cl, Ca, Fe, Ca2+, NO3- and Na+ are in CPM. For Cl- and Na+, major concentrations were found in samples with diurnal south-southwest wind indicating marine aerosol contribution.

Born from the constant questionings that arise from school practices regarding the teaching of History, the present research revolves around the study of the instructions that are given to the teachers by the Ministry of Culture and Education of Brazil (MEC in Portuguese). Therefore, a reflection is sought, when it comes to the possibilities and limitations of putting into practice in public schools an educational proposal that favors the student as a producer of knowledge by means of critiquing historical documents. For that, a dialogue is thought of to be established about the latest changes in school practices and public policies (notably through the use of the Curricular National Parameters P.C.N. in Portuguese), in addition to an attentive look towards evolution, also in the historical research. By means of this study, it is considered that the indication made *through the use of the Curricular National Parameters lead to a teaching proposal which privileges the analysis and criticism of traces from the past (in its most variable discursive manifestations) as well as bringing closer together the institution and the historical research itself. Meanwhile, the practices of the public school History teachers are taken into account, by means of questionnaires that are given, with the purpose of evidencing that which, in fact is being done inside the middle school classrooms in the city of Rio Grande. From the analysis of the results that these questionnaires provide, it s possible to note that, despite the fact the Parameters (P.C.N.) proposal has not been mentioned by the teachers-collaborators, historical sources are continually utilized as didactic and methodological resources in the classes rendered by the great majority of them. At last, the data gathering is done through a trial proposal in a ninth-grade class in Mate Amargo Municipal School (Rio Grande/RS). Such proposal is organized based on MEC s parameterization given to the elementary 4th cycle school teachers. The student s concept about sources and historical knowledge, as well as the school practices referent to the proposal, lead to an analysis in the concluding part of this research. / Nascida dos constantes questionamentos das práticas escolares referentes ao ensino da História, a presente pesquisa volta-se ao estudo da orientação dada aos professores pelo Ministério de Educação (MEC) brasileiro. Busca-se, então, uma reflexão acerca dos limites e possibilidades de se colocar em prática nas escolas públicas uma proposta de ensino que privilegie o estudante como produtor do conhecimento através da crítica ao documento histórico. Para tanto, pensou-se em estabelecer um diálogo sobre as recentes mudanças nas práticas escolares e políticas públicas notadamente através dos Parâmetros Curriculares Nacionais além de um atento olhar para a evolução, também, na pesquisa histórica. Por meio deste estudo, considerou-se que a indicação feita pelos PCN conduz a uma proposta de ensino que privilegia a análise e crítica de vestígios do passado em suas mais variadas manifestações discursivas , bem como a consequente aproximação entre a escola e a pesquisa histórica. Nesse ínterim, são consideradas as práticas dos professores de História da rede pública através de questionários aplicados na intenção de evidenciar aquilo que, de fato, está sendo feito nas salas de aula do Ensino Fundamental no município do Rio Grande. Dentre o saldo da análise dos questionários, é possível perceber que, mesmo sem que a proposta dos Parâmetros tenha sido mencionada pelos professores-colaboradores, as fontes históricas são recorrentemente utilizadas como recursos didático-metodológicos das aulas ministradas pela maioria desses. Por fim, a coleta dos dados foi feita através de uma proposta de experimentação em uma turma de 9º ano da Escola Municipal Mate Amargo (Rio Grande/RS). Tal proposta foi organizada com base na parametrização dada pelo MEC aos professores do 4º ciclo do Ensino Fundamental. As concepções dos estudantes sobre fontes e conhecimento histórico, bem como as práticas escolares referentes à proposta, conduziram a análise na parte final desta pesquisa.

Magister Scientiae (Biodiversity and Conservation Biology) / Elevated temperatures accompanying climate warming are expected to have adverse effects on sensitive lichen species. This premise was examined by measuring the sensitivity of different lichen species to elevated temperatures in the laboratory and in the field. Laboratory studies involved the exposure of nine hydrated lichen species (Xanthoparmelia austro-africana, X. hyporhytida, Xanthoparmelia sp., Xanthomaculina hottentotta, Teloschistes capensis, Ramalina sp., Flavopuntelia caperata, Lasallia papulosa, Parmotrema austrosinensis) collected from sites of different aridity and mean annual temperature for 2 hourly intervals to temperatures ranging from 24ºC to 48ºC in a forced daft oven and measuring their respiration rates and maximum quantum yield of PSII. Field studies involved simultaneous hourly measurements of ground surface air temperatures and Lichen effective quantum yield of PSII of hydrated lichen species populations under ambient and artificially modified environmental conditions. / South Africa

This research project aimed at evaluating four internationally accepted leachate extraction tests to determine their applicability on sewage sludge samples. Furthermore, the present analytical method to determine the leachable fraction of sludge for compliance to South African sludge legislation was evaluated. Leaching tests are done on sludge samples to determine element mobility. This is important since land application of sewage sludge is an accepted and regulated sludge management practice. A literature survey was done to evaluate the mobility over time of metals originating from sludge-amended soils. Mobility is initially due to the organic content of the soil and after organic matter decomposition, it is dependant on the inorganic content. Mobile metals in sludge-amended soil can cause potential environmental risks like groundwater contamination and metal accumulation in soil. Metal accumulation can further lead to increased plant uptake of metals. To determine the partitioning or fractionation of metals found in sludge-amended soil, selective sequential extractions and single extractions can be used. Since South African sludge legislation specifies a single extraction procedure, four were selected for comparative studies. The selected procedures were the USA Environmental Protection Agency (EPA) Toxicity Characteristic Leaching Procedure (TCLP) the Australian Standard Bottle leaching Test (AS 4439.3) the Nederlands Normalisatie-Insitiuut availability test (NEN 7341) and the Deutches Institut für Normung water leachability test (DIN 38 414-S4). A variation of the TCLP is specified for use in South Africa. Three sewage sludge sample lots were collected. The first consisted of 24 sub-samples that were collected from 24 different wastewater treatment works on the East Rand. Both leachable (TCLP) and total (aqua regia) extraction was done on these samples for Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Zn, Se, B and Fe. A relationship between the leachable and total extractions was found for Co and Pb but could not be tested by literature values due to a variation in the sample preparation. The TCLP leachates were also analysed by Atomic Absorption and Inductively Coupled Plasma techniques to compare the applicability of the two. It was found that both techniques are acceptable for leachate analysis. The second sample lot collected from a single wastewater treatment plant was used to determine the leachable effect of the difference between the South African adapted TCLP and the USA EPA procedure as well as the NEN procedure. The EPA specifies all samples be extracted on an “as is” basis while the South African adaptation specifies dry samples. It was found that no element was comparative between dry and wet sample for both extraction procedures. It was observed that wet extractions yield generally higher values than dry extractions. A third sample lot was collected two months after the second sample lot at the same wastewater treatment works. It was used to compare the four extraction procedures. From this it was found that the DIN yielded the highest results for the specified elements. This procedure could not be recommended since the experimental difficulties and the duration of the test make it an unsuitable regulatory compliance tests protocol. / Dissertation (MSc (Environmental Technology))--University of Pretoria, 2006. / Chemical Engineering / unrestricted

Our vision is as yet unsurpassed by machines because of the sophisticated representations of objects in our brains. This representation is vastly different from a pixel-based representation used in machine storages. It is this sophisticated representation that enables us to perceive two faces as very different, i.e, they are far apart in the “perceptual space”, even though they are close to each other in their pixel-based representations. Neuroscientists have proposed distances between responses of neurons to the images (as measured in macaque monkeys) as a quantification of the “perceptual distance” between the images. Let us call these neuronal dissimilarity indices of perceptual distances. They have also proposed behavioural experiments to quantify these perceptual distances. Human subjects are asked to identify, as quickly as possible, an oddball image embedded among multiple distractor images. The reciprocal of the search times for identifying the oddball is taken as a measure of perceptual distance between the oddball and the distractor. Let us call such estimates as behavioural dissimilarity indices. In this thesis, we describe a decision-theoretic model for visual search that suggests a connection between these two notions of perceptual distances. In the first part of the thesis, we model visual search as an active sequential hypothesis testing problem. Our analysis suggests an appropriate neuronal dissimilarity index which correlates strongly with the reciprocal of search times. We also consider a number of alternative possibilities such as relative entropy (Kullback-Leibler divergence), the Chernoff entropy and the L1-distance associated with the neuronal firing rate profiles. We then come up with a means to rank the various neuronal dissimilarity indices based on how well they explain the behavioural observations. Our proposed dissimilarity index does better than the other three, followed by relative entropy, then Chernoff entropy and then L1 distance. In the second part of the thesis, we consider a scenario where the subject has to find an oddball image, but without any prior knowledge of the oddball and distractor images. Equivalently, in the neuronal space, the task for the decision maker is to find the image that elicits firing rates different from the others. Here, the decision maker has to “learn” the underlying statistics and then make a decision on the oddball. We model this scenario as one of detecting an odd Poisson point process having a rate different from the common rate of the others. The revised model suggests a new neuronal dissimilarity index. The new dissimilarity index is also strongly correlated with the behavioural data. However, the new dissimilarity index performs worse than the dissimilarity index proposed in the first part on existing behavioural data. The degradation in performance may be attributed to the experimental setup used for the current behavioural tasks, where search tasks associated with a given image pair were sequenced one after another, thereby possibly cueing the subject about the upcoming image pair, and thus violating the assumption of this part on the lack of prior knowledge of the image pairs to the decision maker. In conclusion, the thesis provides a framework for connecting the perceptual distances in the neuronal and the behavioural spaces. Our framework can possibly be used to analyze the connection between the neuronal space and the behavioural space for various other behavioural tasks.

Le COS est une impureté soufrée acide particulièrement problématique dans les industries du raffinage et de production d’énergie. Son élimination nécessite la mise en œuvre de méthodes spécifiques, nommément des procédés d’adsorption et d’hydrolyse catalytique.Ce travail de thèse a été entrepris dans le but d’identifier les leviers d’amélioration de ces procédés via l’étude des interactions du COS avec la surface d’oxydes métalliques utilisés comme adsorbant ou catalyseur, des phénomènes de compétition d’adsorption avec le CO2 et l’H2S, et du vieillissement des adsorbants.La combinaison de plusieurs techniques expérimentales (ATG, spectroscopie IR, chromatographie inverse) a été mise en œuvre. Il a été montré que la proportion des groupements hydroxyles de la surface avec lequel le COS interagit est très faible, bien qu’elle augmente avec la basicité des solides (nature de l’oxyde et dopage). Simultanément à cette adsorption, le COS est partiellement hydrolysé au contact des groupements hydroxyles de surface, non régénérés par la suite, et responsable en partie d’une baisse de la capacité d’adsorption au cours du cyclage. L’étude de la co-adsorption des trois espèces COS, CO2 et H2S a permis de mettre en évidence des compétitions d’adsorption entre COS et CO2 interagissant avec des groupements hydroxyles similaires, alors que l’H2S interagit de préférence avec les sites acides de Lewis. La formation de soufre élémentaire a également été observée lors des expériences d’adsorption. Celle-ci est directement corrélée à l’acidité de surface, dont les sites acides de Lewis semblent agir comme des oxydants – accepteurs d’électrons – vis-à-vis de l’H2S. / COS is a sulfuric impurity particularly problematic in refining and energy production industries. Its elimination requires specific methods such as adsorption or catalytic hydrolysis processes. The work has as objective the amelioration of COS elimination process by studying COS interaction with oxide surfaces used as adsorbents or catalysts, adsorption competition with CO2 and H2S and adsorbent aging. Three experimental technics were used (IR spectroscopy, TGA, reverse chromatography). It has been shown that not all hydroxyl groups interacts with COS even if their basicity was enhanced by doping. In parallel to its adsorption, COS is partially hydrolyzed by some unregenerated hydroxyl groups. This causes performance lose during cycling. COS co-adsorption with CO2 or H2S shows adsorption competition between COS and CO2 for the same hydroxyl groups. H2S mainly interacts with Lewis acid sites. Elemental sulfur was observed and was correlated to surface acidity where lewis acid sites could act as electron acceptors for H2S.