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Made available in DSpace on 2014-06-11T19:22:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-12Bitstream added on 2014-06-13T20:09:14Z : No. of bitstreams: 1 andrade_gjm_me_botfca.pdf: 821444 bytes, checksum: 8cc3eea959c47aa4add341aa52550caf (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Frente a dúvida sobre a nutrição da soja com manganês influenciada pelo glyphosate e a inclusão do gene de resistência, objetivou-se estudar o acúmulo e distribuição do nutriente na planta de soja geneticamente modificada sob efeito da aplicação de glyphosate, assim como a cinética de absorção do Mn pela soja transgênica sob ação do mesmo herbicida. Foram conduzidos dois experimentos em casa de vegetação no Departamento de Produção Vegetal - Agricultura da Faculdade de Ciências Agronômicas, UNESP-Botucatu. Experimento 1: Em delineamento de blocos completos ao acaso e em esquema fatorial 5 x 3, com quatro repetições, a absorção e o acúmulo de Mn foram avaliados em duas cultivares de soja quase isogênicas (Conquista e Valiosa RR), cultivadas em solução nutritiva. Foram empregados os seguintes níveis de Mn à solução nutritiva: 0; 0,085; 0,125; 0,250; 0,500 mg L-1. Após 25 dias de cultivo as plantas de soja transgênica, destinadas ao estudo sob efeito do glyphosate, foram submetidas à aplicação do herbicida, formulado a base do sal de isopropilamina, via foliar, na dose de 720 g e.a. ha-1. Todas as plantas de soja, convencional e transgênica, com e sem a adição do herbicida, foram coletadas na mesma data (15 dias após a aplicação do herbicida). Realizaram-se divisões das plantas em raízes, hastes e folhas, para a determinação da massa de matéria seca (MMS) e os teores de Mn. Experimento 2: O estudo da cinética de absorção do Mn pela cultivar Valiosa RR foi organizado em delineamento de blocos completos ao acaso, com sete repetições. As plantas foram submetidas ao glyphosate aos 26 dias de cultivo, o qual foi aplicado via foliar, com a mesma formulação do experimento anterior, nas doses de 0 (zero), 15 e 960 g e.a. ha-1. Utilizando-se da técnica de exaustão do Mn na solução, após quatro dias da aplicação do herbicida foi realizado... / Faced with questions about the nutrition of soybean with manganese influenced by glyphosate and the inclusion of the resistance gene, it was aimed to study the accumulation and partition of nutrient in soybean plant genetically modified under effect of glyphosate and the kinetics of Mn absorption by soybean GM under the action of the same herbicide. It was run two experiments in a greenhouse at the Department of Plant Production, Faculty of Agronomic Sciences, UNESP-Botucatu. Experiment 1: In a randomized complete block design and in a 5 x 3 factorial scheme, with four replications, the absorption and accumulation of Mn was evaluated in two cultivars of soybean near-isogenic (Conquista and Valiosa GR), that was grown in nutrient solution. The following Mn levels of the nutrient solution were utilized: 0, 0.085, 0.125, 0.250, 0.500 mg L-1. After 25 days of GR soybean plants cultivation, the leaves of soybean were sprayed with glyphosate formulations on the basis of isopropylamine salt using 720 g a.e. ha-1. All soybean plants, conventional, GR, with and without glyphosate, were collected on the same date (15 days after herbicide application). Then they were separated by roots, stems and leaves, for the determination of dry matter and Mn concentration. Experiment 2: The experiment was randomized using complete block design with seven replicates studying the kinetics of Mn uptake by GR Valiosa soybean cultivar under doses of glyphosate. After 26 days of soybean cultivation the glyphosate was applied with the same wording of the previous experiment, using doses of 0 (zero), 15 and 960 g a.e. ha-1 doses. Using the technique of Mn exhaustion from the nutrient solution after four days of herbicide application, it was carried out a study of the kinetics of Mn absorption. Righ after the end of the experiment of exhaustion, the plants were harvested and separated in leaves, stems and roots for... (Complete abstract click electronic access below)

Orientador: Ciro Antonio Rosolem / Banca: José Lavres Junior / Banca: Marcelo Rocha Corrêa / Resumo: Frente a dúvida sobre a nutrição da soja com manganês influenciada pelo glyphosate e a inclusão do gene de resistência, objetivou-se estudar o acúmulo e distribuição do nutriente na planta de soja geneticamente modificada sob efeito da aplicação de glyphosate, assim como a cinética de absorção do Mn pela soja transgênica sob ação do mesmo herbicida. Foram conduzidos dois experimentos em casa de vegetação no Departamento de Produção Vegetal - Agricultura da Faculdade de Ciências Agronômicas, UNESP-Botucatu. Experimento 1: Em delineamento de blocos completos ao acaso e em esquema fatorial 5 x 3, com quatro repetições, a absorção e o acúmulo de Mn foram avaliados em duas cultivares de soja quase isogênicas (Conquista e Valiosa RR), cultivadas em solução nutritiva. Foram empregados os seguintes níveis de Mn à solução nutritiva: 0; 0,085; 0,125; 0,250; 0,500 mg L-1. Após 25 dias de cultivo as plantas de soja transgênica, destinadas ao estudo sob efeito do glyphosate, foram submetidas à aplicação do herbicida, formulado a base do sal de isopropilamina, via foliar, na dose de 720 g e.a. ha-1. Todas as plantas de soja, convencional e transgênica, com e sem a adição do herbicida, foram coletadas na mesma data (15 dias após a aplicação do herbicida). Realizaram-se divisões das plantas em raízes, hastes e folhas, para a determinação da massa de matéria seca (MMS) e os teores de Mn. Experimento 2: O estudo da cinética de absorção do Mn pela cultivar Valiosa RR foi organizado em delineamento de blocos completos ao acaso, com sete repetições. As plantas foram submetidas ao glyphosate aos 26 dias de cultivo, o qual foi aplicado via foliar, com a mesma formulação do experimento anterior, nas doses de 0 (zero), 15 e 960 g e.a. ha-1. Utilizando-se da técnica de exaustão do Mn na solução, após quatro dias da aplicação do herbicida foi realizado... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Faced with questions about the nutrition of soybean with manganese influenced by glyphosate and the inclusion of the resistance gene, it was aimed to study the accumulation and partition of nutrient in soybean plant genetically modified under effect of glyphosate and the kinetics of Mn absorption by soybean GM under the action of the same herbicide. It was run two experiments in a greenhouse at the Department of Plant Production, Faculty of Agronomic Sciences, UNESP-Botucatu. Experiment 1: In a randomized complete block design and in a 5 x 3 factorial scheme, with four replications, the absorption and accumulation of Mn was evaluated in two cultivars of soybean near-isogenic (Conquista and Valiosa GR), that was grown in nutrient solution. The following Mn levels of the nutrient solution were utilized: 0, 0.085, 0.125, 0.250, 0.500 mg L-1. After 25 days of GR soybean plants cultivation, the leaves of soybean were sprayed with glyphosate formulations on the basis of isopropylamine salt using 720 g a.e. ha-1. All soybean plants, conventional, GR, with and without glyphosate, were collected on the same date (15 days after herbicide application). Then they were separated by roots, stems and leaves, for the determination of dry matter and Mn concentration. Experiment 2: The experiment was randomized using complete block design with seven replicates studying the kinetics of Mn uptake by GR Valiosa soybean cultivar under doses of glyphosate. After 26 days of soybean cultivation the glyphosate was applied with the same wording of the previous experiment, using doses of 0 (zero), 15 and 960 g a.e. ha-1 doses. Using the technique of Mn exhaustion from the nutrient solution after four days of herbicide application, it was carried out a study of the kinetics of Mn absorption. Righ after the end of the experiment of exhaustion, the plants were harvested and separated in leaves, stems and roots for... (Complete abstract click electronic access below) / Mestre

Actuellement, on observe le développement de nouveaux matériaux, à savoir les matériaux actifs, au travers de divers processus et applications. Par exemple, l’utilisation de nanoparticules de fer (NanoFe) absorbantes d’O2 dans le cadre de l’emballage actif, implique la maîtrise de plusieurs paramètres pour une application en tant que matériau actif. En effet, il est indispensable d’avoir une très bonne compréhension des mécanismes d’oxydation et de consommation d’O2, de pouvoir quantifier les capacités d’absorption ainsi que la vitesse d’absorption d’O2. Bien que nécessaires, ces deux paramètres n’ont été jusqu’à présent que peu caractérisés et encore moins mis en relation avec les propriétés morphologiques (tailles, surface spécifique, etc) et physico-chimiques (tel que l’état du fer) des nanoparticules de fer mises en oeuvre.Dans le but de concevoir à façon un film d’emballage monocouche absorbeur d’O2, ce travail vise à combiner une barrière passive, liée au phénomène de tortuosité induit par la présence des lamelles d’argile dispersées dans une matrice polymérique et une barrière active, liée à l’absorption d’oxygène par les NanoFe synthétisées. Les Nano-Fe ont été synthétisées par réduction chimique au Borohydrure de sodium sur support d’argile Montmorillonite (MMT). La caractérisation MET a révélé la formation d'agrégats de nanoparticules de fer d'une taille moyenne de 57 ± 17 nm dispersées sur la surface des MMT. La cinétique Mössbauer sur la poudre MMT-Fe confirme que les différentes phases du fer (Fe0 et FeII) dans les nanoparticules de fer ne s'oxydent pas à la même vitesse. Cela a permis d’ajuster le modèle mathématique de prédiction des propriétés d’absorption de l’O2. L'étude de propriétés d'absorption d’O2 sur les poudres a montré que la constante de réaction (k), le coefficient de proportionnalité (n) et les capacités d'absorption d’O2 sont du même ordre de grandeur pour la poudre humide, séchée et stockée. Les films nanocomposites préparés à partir des poudres séchées de MMT-Fe synthétisées, incorporées dans un polymère de LLDPE ont montré une bonne capacité d’absorption, mais inférieure à celle de la poudre seule, lié à l’oxydation avancée du fer dans ces films, confirmée par la spectroscopie Mössbauer (les films sont oxydés à 60% contre 30% pour les poudres). Un modèle numérique utilisant la seconde loi de Fick couplée au système d’équations de cinétique chimique obtenue sur la poudre, a permis de prédire le phénomène de diffusion et réaction de l'oxygène dans des films réalisés. Ce modèle est comparé aux données expérimentales obtenues par oxydation de films. En parallèle, une étude de la cinétique d'absorption d’absorbeurs d’O2 commerciaux, couramment utilisés dans les emballages sous atmosphère modifiée, a été effectuée. Sur ces systèmes commerciaux, la cinétique d'absorption a été décrite aussi par une réaction de cinétique de second ordre avec un comportement de type Arrhenius pour l’effet de la température. Toutefois, la spectroscopie Mössbauer a révélé que, dans ce cas-là, seule l’espèce Fe0 était prépondérante pour décrire la cinétique (celle de FeII étant négligeable tant elle est rapide). Nous avons montré pour la première fois, que la spectroscopie de Mössbauer peut être couplée avec succès à la mesure de l'oxygène afin de caractériser in situ l’oxydation du fer, sa spéciation et la capacité d’absorption d’O2. Cette configuration associant spectroscopie de Mössbauer et mesure de l’oxygène ont fourni des informations précieuses sur les mécanismes réactionnels régissant les absorbeurs d’O2. Tous ces résultats auront des implications importantes pour la compréhension de l’absorption d’oxygène dans le système actif absorbeur d’O2. / Currently, we are seeing the development of new materials, namely active materials, through various processes and applications. Among these active materials, the use of O2 scavenging iron nanoparticles (NanoFe) as required knowledge of several parameters for efficient application in the field of food packaging such as knowledge about oxidation mechanism and O2 consumption rate. These parameters are necessary to be able to quantify the absorption capacity and absorption rate of O2. Although necessary, these two parameters have so far been little characterized and even less related to the morphological (size, specific surface, etc.) and physico-chemical properties (such as the iron speciation) of iron nanoparticles implemented.In order to tailor nanocomposite film with O2 scavenging properties, this work aims to combine a passive barrier, related to the phenomenon of tortuosity induced by the presence of clay platelets dispersed in a polymeric matrix and an active barrier, related to oxygen uptake by synthesized NanoFe. Nano-Fe were synthesized by chemical reduction with sodium borohydride on Montmorillonite clay (MMT) support. The TEM characterization revealed the formation of iron nanoparticle aggregates with an average size of 57 ± 17 nm scattered on the MMT surface. The Mössbauer kinetics on the MMT-Fe powder confirms that the different iron phases (Fe0 and FeII) in the iron nanoparticles do not oxidize at the same speed. This allowed to adjust the mathematical model of O2 absorption properties prediction. The study of O2 absorption properties on powders has shown that the reaction constant (k), the proportionality coefficient (n) and the O2 absorption capacities are of the same order of magnitude for the wet, dried and stored powders. The nanocomposite films prepared from the synthesized MMT-Fe dried powders incorporated in a LLDPE polymer showed good absorption capacity, but lower than that of the fresh powder, related to the advanced oxidation of iron in these films, confirmed by Mössbauer spectroscopy (films are 60% oxidized versus 30% for powders). A numerical model using the second law of Fick coupled to the system of chemical kinetics equations obtained on the powder, made it possible to predict the phenomenon of diffusion and reaction of oxygen in films produced. This model was compared with experimental data obtained by measuring O2 absorption by films. In parallel, a study of the absorption kinetics of commercial O2 scavengers, commonly used in modified atmosphere packaging, was carried out. On these commercial systems, absorption kinetics has also been described by a second-order kinetic reaction with Arrhenius-like behavior for the effect of temperature. Mössbauer spectroscopy revealed that, in this case, only the Fe0 species were predominant to describe the kinetics (that of FeII being negligible as it was fast). We have shown for the first time that Mössbauer spectroscopy can be successfully coupled to the measurement of oxygen in order to characterize iron oxidation, speciation and O2 absorption capacity in situ. This configuration associating Mössbauer spectroscopy and oxygen measurement provided valuable information on the reaction mechanisms governing the O2 absorbers. All of these results will have important implications for understanding oxygen uptake in the active O2 absorber system.

Made available in DSpace on 2014-12-17T15:01:19Z (GMT). No. of bitstreams: 1 LuizFSF.pdf: 1747527 bytes, checksum: e75c5e8a2575620cc3a29490253bcad6 (MD5) Previous issue date: 2009-03-05 / Natural gas, although basically composed by light hydrocarbons, also presents in its composition gaseous contaminants such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). Hydrogen sulfide, which commonly occurs in oil and gas exploration and production activities, besides being among the gases that are responsible by the acid rain and greenhouse effect, can also cause serious harm to health, leading even to death, and damages to oil and natural gas pipelines. Therefore, the removal of hydrogen sulfide will significantly reduce operational costs and will result in oil with best quality to be sent to refinery, thereby resulting in economical, environmental, and social benefits. These factors highlight the need for the development and improvement of hydrogen sulfide sequestrating agents to be used in the oil industry. Nowadays there are several procedures for hydrogen sulfide removal from natural gas used by the petroleum industry. However, they produce derivatives of amines that are harmful to the distillation towers, form insoluble precipitates that cause pipe clogging and produce wastes of high environmental impact. Therefore, the obtaining of a stable system, in inorganic or organic reaction media, that is able to remove hydrogen sulfide without forming by-products that affect the quality and costs of natural gas processing, transport and distribution is of great importance. In this context, the evaluation of the kinetics of H2S removal is a valuable procedure for the treatment of natural gas and disposal of the byproducts generated by the process. This evaluation was made in an absorption column packed with Raschig ring, where natural gas with H2S passes through a stagnant solution, being the contaminant absorbed by it. The content of H2S in natural gas in column output was monitored by an H2S analyzer. The comparison between the obtained curves and the study of the involved reactions have not only allowed to determine the efficiency and mass transfer controlling step of the involved processes but also make possible to effect a more detailed kinetic study and evaluate the commercial potential of each reagent / O g?s natural, embora seja composto basicamente de hidrocarbonetos leves, apresenta tamb?m em sua composi??o gases contaminantes como o CO2 (Di?xido de carbono) e o H2S (Sulfeto de hidrog?nio). O H2S, que comumente ocorre nas atividades de explora??o e produ??o de ?leo e g?s, al?m de estar entre os respons?veis pela chuva ?cida e pelo efeitoestufa, causa s?rios danos ? sa?de, levando inclusive ? morte, e danifica as tubula??es de transporte do petr?leo e do g?s natural. Por isso, eliminando-se o g?s sulf?drico haver? significativa redu??o dos custos de opera??o e uma melhor qualidade do ?leo destinado ? refinaria, resultando assim num beneficio econ?mico, ambiental e social. Tudo isso demonstra a necessidade do desenvolvimento e aprimoramento de seq?estrantes que removam o sulfeto de hidrog?nio da ind?stria de petr?leo. Atualmente existem v?rios processos para o tratamento do g?s natural utilizados pela ind?stria petrol?fera para remo??o do H2S, no entanto eles produzem derivados de aminas prejudiciais ?s torres de destila??o, precipitados insol?veis que provocam entupimento dos dutos e originam res?duos de grande impacto ambiental. Por isso, a obten??o de um sistema est?vel em meio reacional inorg?nico ou org?nico capaz de remover o g?s sulf?drico sem formar subprodutos que afetem a qualidade e o custo do processamento, transporte e distribui??o do g?s natural ? de grande import?ncia. Nesse contexto a avalia??o da cin?tica de remo??o do H2S surge como um procedimento valioso para o tratamento do g?s natural e destino dos subprodutos do processo. Esta avalia??o foi feita numa coluna de absor??o recheada com an?is de Raschig, por onde o g?s natural contaminado com H2S atravessava uma solu??o estagnada, sendo por esta absorvida. Na sa?da da coluna o teor de H2S no g?s era monitorado por um analisador de H2S. A compara??o das curvas obtidas e o estudo das rea??es permitiram n?o somente determinar a efici?ncia e a etapa controladora da transfer?ncia de massa dos processos envolvidos como tamb?m efetuar um estudo cin?tico mais aprofundado e avaliar o potencial comercial de cada reagente

L'utilisation des composites biosourcés dans des applications extérieures pour le génie civil pose le problème de leur durabilité dans les conditions d'utilisation, en raison de la forte hydrophilie des fibres naturelles. En effet, le comportement de ces composites en présence d’eau et d’humidité ou face aux contraintes thermiques et agressions biologiques est mal connu. L’objectif de cette thèse est d’étudier, par des analyses multi-échelles, la réversibilité des évolutions des propriétés de composites à matrice polyéthylène renforcée par des fibres courtes de lin. Pour ce faire, des cycles humidification/séchage ont été réalisés lors de vieillissement hydro et hygrothermiques, à 30 et 80°C. L’influence du taux de fibres et de la qualité de l'interface sur l’évolution de ces propriétés a été évaluée. De même, une étude de l’impact du développement microbien sur les composites a été réalisée pendant 6 mois. Après une caractérisation initiale des matériaux, les évolutions des caractéristiques cinétiques de coefficients de diffusion et de prise de masse au cours des vieillissements ont été évaluées. Ainsi, deux phénomènes antagonistes semblent gouverner l'évolution du coefficient de diffusion des composites. Dans un second temps, la caractérisation mécanique de ces composites au cours du vieillissement a permis d'identifier les phénomènes mis en jeu. Les évolutions du module mécanique à 30°C sont réversibles après séchage et sont attribuées à une plastification des microfibrilles de cellulose. Ces chutes s'accentuent et deviennent irréversibles à 80°C, mettant en évidence des dégradations plus importantes des matériaux. Dans un troisième temps, le phénomène de dégradation biologique de ces matériaux a été étudié. Il a été vérifié que les microorganismes sont responsables de consommation sélective de composants de fibres de lin et que leur croissance est favorisée par le taux de fibres dans le composite / The use of bio-based composites in outdoor applications for civil engineering raises the issue of their sustainability in service. This is mainly due to the highly hydrophilic character of natural fibers. Indeed, the behavior of these composites in a wet environment or under thermal and biological constraints is not well known. The main objective of this study is to get a better understanding of the reversibility of bio-based composites properties. Therefore, wetting/ drying cycles were performed on polyethylene/short flax fibre composites under hydro and hygrothermal ageing at 30 and 80°C. The influence of the fiber content and the interface quality on the mechanical properties was monitored. Moreover, a 6 months study of a microbial growth impact on these composites was carried out. A characterization of the non-aged materials was conducted first. Then, the kinetic parameters such as the water diffusion coefficient and the weight changes due to ageing were determined. Two competing mechanisms seem to affect the diffusion coefficient. The mechanical characterization of these composites during aging has enabled the identification of the aging mechanisms. Changes in the mechanical modulus at 30°C were mostly reversible after a drying cycle and were associated with a plasticizing effect of the water molecules on the cellulose microfibrils. The property losses increase and become irreversible at 80°C, which indicates a higher degradation of the composites. Finally, the biological degradation of these materials has been studied. It was verified that selective consumption of flax fiber components by microorganisms occurs, and that their growth is favored by the fiber content in the composite