Les dispositifs avancés pour la microélectronique intègrent divers matériaux et sont de dimensions nanométriques. Une connaissance précise de leur composition est requise pour améliorer leurs procédés de fabrication et comprendre leur comportement électrique. Le ToF-SIMS est un candidat intéressant, qui souffre cependant des effets de matrice et ne possède pas toujours une résolution spatiale suffisante. Le but de ce travail est de permettre une analyse quantitative et résolue en profondeur de matériaux et structures pour la microélectronique avancée à l'aide d'un ToF-SIMS standard. Cette étude porte sur SiGe, sur des matériaux à haute permittivité, des implants basse énergie et des matériaux organiques. Elle se concentre sur la préparation d'échantillons, l'optimisation des conditions expérimentales et le traitement de données pour mettre au point des protocoles d'analyse originaux dont la précision est évaluée grâce à d'autres techniques de caractérisation de pointe. Ces protocoles permettent d'améliorer la qualité des analyses en termes de résolution en profondeur, de précision et de reproductibilité / Next generation devices for microelectronics feature nanometric dimensions and incorporate heterogeneous materials. Accurate knowledge is needed on their chemical composition to address elaboration processes and understand electrical properties. ToF-SIMS is an interesting candidate, but it suffers from matrix effects and insufficient depth resolution. The aim of this work is to enable quantitative, depth resolved analysis of materials and structures for advanced devices with a standard ToF-SIMS. Studies focus in SiGe and high-k based materials, ultra shallow implants and materials for organic electronics. We investigate sample preparation, experimental condition optimization and data treatment to setup original analysis protocols. Accuracy of the new protocols is tested with leading edge external characterization techniques in each of the materials of interest. These developments allowed enhanced analysis quality in terms of depth resolution, accuracy and reproducibility.

Orientador: Luiz Augusto do Amaral / Banca: Antonella Cristina Bliska Jacinto / Banca: Francisca Neide Costa / Banca: Maria da Glória Buzinaro / Banca: Oswaldo Durival Rossi Junior / Resumo: A água é um recurso natural indispensável à vida, é essencial à promoção social, à produção de alimentos e ao desenvolvimento econômico. Com o objetivo de se avaliar a qualidade microbiológica e físico-química de águas subterrâneas e superficiais na microrregião de Itapecuru-Mirim-MA foram colhidas 172 amostras de água, sendo 86 no período chuvoso (março a maio) e 86 amostras no período de estiagem (agosto a outubro). Destas, 39 amostras eram águas consumidas em residências rurais procedentes de poços artesianos, poços rasos, fontes naturais e Rede Publica de Abastecimento, 05 eram de uso doméstico, 08 de lavagem dos tetos das vacas; 02 de uso em laticínios, 01 de uso em matadouro, 01 de fábrica de polpas de frutas, 18 de bebedouros dos animais, 09 águas de uso em piscicultura e 03 de irrigação de hortaliças. Foram analisados parâmetros microbiológicos e físico-químicos e aplicado um questionário fechado contendo perguntas objetivas para se avaliar o nível de conhecimento das pessoas quanto à qualidade da água usada ou consumida e mapeado geograficamente os pontos de colheitas. Os resultados das análises microbiológicas e físico-químicas identificaram 52 (66,66 %) amostras de água de consumo humano em desacordo com os padrões microbiológicos e 23 (29,48%) em desacordo com os parâmetros físico-químicos, nove (90%) amostras de água de uso doméstico não atenderam aos padrões microbiológicos, enquanto seis (60%) não o foram para os padrões físico-químicos, para água de lavagem dos tetos evidenciaramse 13 (81,25%) e 10 (62,50%) amostras, respectivamente, fora dos padrões microbiológicos e físico-químicos vigentes. Não foi constatada contaminação microbiológica nem físico-química para água de uso em laticínio e em fábrica de polpa de frutas. Referente à água de uso em matadouro, uma (50%) amostra não atendeu aos padrões... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Water is a natural resource essential for life, it is essential to social promotion, food production and economic development. In order to evaluate the microbiological and physical chemistry quality of groundwater and surface water in the municipality of Itapecuru-Mirim-MA were collected 172 water samples, including 86 in the rainy season (March-May) and 86 samples in the dry weather period (August- October). From these total, 39 samples were water consumed in rural residences coming from shallow water wells, artesian water wells, natural sources and public water supply, 05 were domestic water, 08 from teat washings of cows; 02 for use in dairy products, 01 from the slaughterhouse, 01 from a factory fruit pulps, 18 from animal drinking fountains, 09 water samples used for pisciculture and 03 from vegetables irrigation. They were all analyzed for the microbiological and physical-chemical parameters. A close questionnaire with objective questions was also applied to evaluate the awareness level of people about the water quality used or consumed and the crops points were geographically mapped. The microbiological and physical-chemical results identified 52 (66,66%) water samples for human consumption in discordance with the microbiological standards and 23 (29,48%) in discord to the physical-chemical parameters, nine (90%) water samples for domestic use did not attend to the microbiological standards, while six (60%) were not for the physical-chemical parameters. The teat washing water results showed that 13 (81,25%) and 10 (62,50%) samples, respectively, were out of the microbiological and physical-chemical actual patterns. It was not detected microbiological contamination of water used in the dairy and in the fruit pulp factory. Referring to the water used in the slaughterhouse, one (50%) sample did not attend to the microbiological patterns, but all samples attended to the physical-chemical...(Complete abstract click electronic access below) / Doutor

L’objectif de cette étude est d’étudier l’impact de la fraction volatile odorante et de la fraction non-volatile sur la perception de la flaveur du caramel. Dans la première étape, la fraction volatile du caramel a été analysée par Chromatographie en Phase Gazeuse couplée à l’Olfactométrie (GC/O), par GC couplée à la Spectrométrie de Masse (GC/MS) et par heart-cutting MDGC. Les résultats mettent en évidence une centaine de composés volatils et démontrent la richesse aromatique du caramel. L’objectif de la deuxième étape était d’évaluer la contribution de ces composes volatils à la typicité odorante du caramel. Des études ont montré que l’intensité odorante n’était pas suffisante pour évaluer l’impact des composés. Ce travail de thèse propose une approche originale de recombinaison d’odeur à partir de composés triés selon leur qualité odorante. Les résultats montrent que la typicité odorante caramel est le fruit d’un équilibre entre les notes caramel, fruité, fruits secs, végétal, animal, grillé, floral et piquant. Des tests d’addition, d’omission et d’un plan d’expérience factoriel complet ont démontré l’existence d’interactions perceptives. L’objectif de la dernière étape était d’étudier l’impact de la fraction non volatile sur la perception de la flaveur du caramel. L’étude de la libération de composés d’arôme in vitro par analyses SPME/GC/MS dans différentes matrices non volatiles démontre l’existence d’interactions physico-chimiques entre les composés d’arôme et les macromolécules non volatiles. Ces premiers résultats laissent supposer que la fraction non volatile est susceptible de moduler la perception de la flaveur / The aim of this study was to investigate the impact of the volatile odorant fraction and the non-volatile matrix on the perception of the caramel flavour. The first step focused on the analytical characterization of the volatile odorant fraction of aromatic caramel thanks to Gas Chromatography coupled to Olfactometry (GC/O), GC/Mass Spectrometry (GC/MS) and heart-cutting MDGC/MS/O. Results highlighted the presence of more than one hundred compounds and demonstrated the complexity of the caramel volatile fraction. The objective of the second step was to understand the contribution of odorant compounds identified to the caramel aroma typicality. Literature shows that odour intensity is not sufficient to evaluate the impact of compounds on the aroma. This thesis proposed an original approach to carry out the aroma recombination by taking into account odour qualities. Results showed that the caramel typicality results from a complex balance between caramel, fruity, vegetal, sharp, nutty, floral, roasted and animal odours. Omission, addition tests and a 24 factorial design showed the existence of perceptive interactions. The third step focused on studying the impact the macromolecules that constitute the non-volatile fraction on the perception of caramel flavour. In vitro aroma release was followed by SPME/GC/MS in different matrices varying in non-volatile composition. Results evidence physico-chemical interactions between aroma and macromolecule of the non-volatile fraction. Those preliminary results suggest that the non-volatile matrix is able to impact the flavour perception

Les suspensions concentrées sont des fluides qui présentent des propriétés rhéologiques complexes. Ces propriétés sont modélisées par des équations structurelles qui considèrent à la fois les phases liquide et solide, mais avec un manque de lien avec les paramètres granulaires (en particulier la compacité des suspensions non modèles). L'objectif global de ce travail est d'étudier la dépendance de la viscosité de suspensions concentrées énergétiques aux propriétés physico-chimiques de leurs composants. Les propriétés ayant l'impact le plus significatif sur la viscosité sont choisies en utilisant la méthodologie des plans d’expériences. Le modèle résultant représente le diamètre médian D50 en volume de petites et grandes particules, la densité des grosses particules d, la surface spécifique des particules, la contrainte de cisaillement γ ̇ appliquée à la suspension, la viscosité du fluide de suspension ηf et une constante valeur pour la fraction volumique en solide φ≃0.51. De plus, ce modèle permet de prédire la viscosité des suspensions étudiées pour une fraction volumique en solide allant de 0 à 0,51 %. / Concentrated suspensions are fluids which display complex rheological properties. These properties are modelled through structural equations which consider both the liquid and solid phases, but with a lack of consistency for the granular parameters (in particular the maximum packing fraction of non-model suspensions). The overall objective of this paper is to investigate the dependence of the viscosity of energetic concentrated suspensions on the physicochemical properties of their components. The properties with the most significant impact on the viscosity are chosen using the Design of Experiments methodology. The resulting model accounts for the mass median diameter D50 in small and large particles, the large particles density d, the specific surface area of small particles, the shear stress γ ̇ applied to the suspension, the viscosity of the suspending fluid η_f and a constant value for the volume fraction in solid ϕ≃0.51. Moreover, this model allows predicting the viscosity of the studied suspensions for a volume fraction in solid from 0 to 0.51 %

Les performances des dispositifs photovoltaïques organiques (OPV) se sont considérablement améliorées au cours de la dernière décennie. Compte tenu de ces avancées, il est envisageable de transférer cette technologie développée au laboratoire à l’échelle industrielle. Le dépôt de la structure multicouche par le procédé d’impression jet d’encre est le moyen idéal de produire des dispositifs sur mesure, flexibles et potentiellement à faible coût. L’objectif de cette thèse a ainsi été de comprendre et de maitriser l’influence de la formulation des encres sur le procédé d’impression, en allant de l’éjection jusqu’aux performances photovoltaïques des couches imprimées. Les paramètres améliorant la qualité d’éjection ont tout d’abord été déterminés, puis ceux favorisant la mouillabilité. A partir de ces données, les encres ont été formulées pour que leurs propriétés physico-chimiques répondent à ces exigences. Ces nouvelles formulations ont ainsi permis d’optimiser la qualité d’éjection et d’assurer l’obtention d’une couche imprimée uniforme et compatible pour leur intégration en dispositifs OPV. Les couches obtenues après optimisation de la stratégie d’impression se sont avérées aussi performantes que celles réalisées par spin coating, procédé laboratoire de référence. Les avancées mises au point dans ces travaux, en termes de maitrise de la formulation et du procédé jet d’encre, ont contribué à l’amélioration de chacune des couches imprimées du dispositif. D’autre part, la méthodologie mise au point au cours de ce travail pourra s’appliquer à d’autres technologies photovoltaïques, ainsi qu’au domaine de l’électronique organique imprimée / The performances of organic photovoltaic devices (OPV) have been considerably improved over the last decade. These developments allow to scale up the technologies developed at the laboratory scale to the industrial one. For the elaboration of multilayered architectures, inkjet printing method is the ideal way to produce custom-made devices which could be also flexible and potentially low cost. The purpose of this PhD was to understand and to master the influence of ink formulation on the printing process, from the ejection step to the photovoltaic performance characterization of the printed layers. Parameters improving the ejection quality were first determined followed by those making the wettability easier. The inks have been then formulated to ensure that their physicochemical properties meet the aforementioned requirements. These new formulations enabled to optimize the quality of the ejection quality and to ensure uniform printed layers compatible with their integration in OPV devices. After optimization of the printing strategies, the obtained layers proved to be as efficient as those made by spin coating process (reference process at laboratory scale). The advances reached within in this work, in terms of formulations and processes, contributed to the improvement of each inkjet printed layers of the device. Furthermore, the methodology developed here could be applied in the near future either to other photovoltaic technologies and to organic printed electronics.

Dans les conditions réelles d’utilisation, de multiples facteurs sont à l’origine de l’évolution des propriétés mécaniques des caoutchoucs (température, oxygène, conditions de chargement mécaniques…). Les pièces en élastomère pour l’antivibratoire automobile sont généralement massives (plusieurs millimètres d’épaisseur), le vieillissement conduit alors à des évolutions de propriétés hétérogènes. Ceci peut être induit par plusieurs mécanismes de dégradation liés, par exemple, à la présence ou non d’oxygène. Pour comprendre et identifier les mécanismes de dégradation prépondérants, une campagne de vieillissement accéléré a été menée pour une large gamme de températures représentative des conditions de service rencontrées sur véhicule (de 40°C à 120°C). De nombreux échantillons de géométries différentes (films minces, éprouvettes de caractérisation et éprouvettes de structure) ont été utilisés afin, d’une part, de faciliter l’interprétation, et d’autre part, de viser la transposition des résultats à l’échelle des pièces industrielles. L’étude présentée ici vise à identifier les mécanismes physico-chimiques et/ou évolutions microstructurales à l’origine du processus de dégradation, et de quantifier les conséquences de ceux-ci sur le comportement mécanique et les propriétés en fatigue. Ces résultats permettront de fournir les éléments nécessaires à la modélisation et la prise en compte fine des effets du vieillissement dans le processus de conception de pièces antivibratoires automobiles. / Under service conditions, many factors are responsible for the evolution of the mechanical properties of rubber parts (temperature, oxygen, mechanical loadings, etc.). Automotive anti-vibration parts using rubber-like materials are usually massive and ageing can therefore lead to heterogeneous properties. To understand the degradation process and especially the effect of oxygen, aerobic and anaerobic ageing conditions have been studied for a wide range of temperatures (from 40°C to 120°C). Numerous samples have been used with different geometries (from thin films to massive structural samples) to ease the interpretation but also to remain as close as possible from the final applications. The mechanical consequences of the ageing have been investigated for both static and fatigue properties throughout a wide experimental database (about 1000 specimens tested in fatigue, for example). The study aims at identifying the physicochemical mechanisms and/or microstructural evolution that cause the processes of degradation and to quantify the consequences on the mechanical behavior and the fatigue properties. These results will provide the necessary elements needed for the integration of thermo-oxidative effects in the fatigue design loop of automotive anti-vibration parts.

Made available in DSpace on 2014-06-11T19:23:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-04Bitstream added on 2014-06-13T18:50:35Z : No. of bitstreams: 1 carvalho_ccp_me_sjrp.pdf: 1317102 bytes, checksum: 8fd688580bc2bbfa18f313fc2ce6db07 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A linguiça cuiabana tem grande aceitação no município de São José do Rio Preto-SP e regiões adjacentes. Originalmente é constituída de carne bovina (corte traseiro), leite, cebolinha, pimenta bode, pimenta do reino, alho e sal refinado. Atualmente, encontramos no comércio diversos tipos de linguiça cuiabana, diferenciadas por condimentos, queijos, cortes musculares ou por espécies animais (suína, bovina, frango). No presente trabalho, juntamente com seu levantamento histórico, estudaram-se as características tecnológicas/ sensoriais da linguiça cuiabana. Foi realizado o processamento sob condições assépticas, de 4 formulações da linguiça tipo cuiabana, variando a principal matéria-prima utilizada (carne bovina, frango, suína). No processamento, as matérias-primas (bovina, frango e suína) foram cortadas em cubos que, juntamente com outros ingredientes (alho, queijo, pimenta e cebolinha), foram pesados e homogeneizados. A massa resultante foi deixada em repouso sob refrigeração por 24 horas para melhor desenvolvimento do sabor. Após descanso da massa, foi realizado o embutimento em tripas naturais. A partir destas amostras foram realizadas a caracterização do perfil físico-químico e avaliação sob refrigeração, ao longo de 7 dias de armazenamento por meio de análises microbiológicas (coliformes totais e termotolerantes (fecais), clostrídrios sulfito redutores, Salmonella spp., Staphylococcus coagulase positiva), pH, TBA. Por fim, a avaliação sensorial e estatística das diferentes linguiças tipo cuiabana processadas em laboratório. Os resultados mostraram que as variações ao longo do tempo na formulação das linguiças cuiabanas são fatores positivos, ficando evidente que as transformações são bem mais aceitas que a precursora, o que possivelmente ocorreram em função da demanda do mercado. / The cuiabana sausage has wide acceptance in the municipality of Sao Jose do Rio Preto and surrounding regions. Originally, it consisted of beef (cut back), milk, chives, goat pepper, black pepper, garlic and salt. Currently, various types of cuiabana sausage are found in trade and they are distinguished by spices, cheeses, muscle cut or animal species (bovine, chicken and swine). In this paper, along with a historical survey, we studied the technical/ sensory characteristics of cuiabana sausage. Processing was performed under aseptic conditions for 4 formulations of sausage type cuiabana, varying the main raw material (bovine, chicken and swine). In processing, the raw meat (beef, chicken and pork) was cut into cubes, which together with other ingredients (garlic, cheese, pepper and chives), were weighed and homogenized. The resulting mass was subjected to refrigeration for 24 hours in order to develop better. After the dough we rested, the inlay was inserted in natural casings. These samples were used to characterize both the physical-chemical profile and also the evaluation under refrigeration, for over a 7 days-storage in order to assess microbiological contamination (total coliforms and thermotolerant (fecal), sulphite reducing clostrídrios, Salmonella spp. , Staphylococcus coagulase positive), pH, TBA. Finally, the sensory evaluation and statistics of the different types of cuiabana sausage processed in the laboratory were performed. The results showed that changes over time in the formulation of cuiabana sausages are positive factors, demonstrating, thus, that the changes are much more accepted than the precursor, which possibly occurred as a function of market demand.

Made available in DSpace on 2016-12-08T16:24:07Z (GMT). No. of bitstreams: 1 PGCA09MA054.pdf: 260243 bytes, checksum: 0f7b307401cecae66d2650af13dce4dd (MD5) Previous issue date: 2009-06-20 / The main objective of the slaughtering of animals for human consumption is to obtain meat in quantity and with quality. Thus, the meat needs to be within the standards required by current legislation. However, the agroindustry still faces serious problems due to microbiological contamination of carcasses during slaughter and/or processing. Alternatives proposed aiming to decontaminate carcasses during slaughter include treatment with the use of organic acids and/or steam. Such treatments aim to ensure the biological safety of foods and complement the autocontrol programs of industry on a prevention basis, such as hygiene care during the handling of foods and the sanitization of equipment to avoid any type of cross contamination. However, little research has provided conclusive information regarding whether these treatments lead to organoleptic and physico-chemical changes in the pork, which would be completely undesirable in terms of the quality parameters. Thus, this study aims to evaluate the possible physico-chemical changes in pork legs submitted to treatments with organics acids, steam and a combination of the two treatments. Visual and sensory analysis was carried out on the aspect, color, consistency and odor, before and after each treatment, together with physico-chemical analysis in order to determine the pH and the percentage of lipids, proteins, moisture and volatile compounds, also before and after each treatment. The results obtained revealed that the treatments used did not interfere in the attributes of aspect, color, odor and consistency and also did not lead to changes in the physico-chemical properties, with the exception that the treatment using organic acid combined with steam led to a decrease in the pH and increase in the moisture content and volatile compounds in the meat. However, this treatment did not denature the physicochemical quality of the pork, which remained within the standards, and therefore appropriate for human consumption / O abate de animais para o consumo humano tem por objetivo principal a obtenção de carne em quantidade e em qualidade. Para isso, é necessário que a carne esteja dentro dos padrões exigidos pela legislação vigente, porém, as agroindústrias ainda enfrentam sérios problemas com relação à contaminação microbiológica de carcaças durante o abate e/ou processamento. Entre as alternativas propostas visando descontaminar carcaças no abate, tem sido proposto o tratamento com uso de ácidos orgânicos e/ou vapor. Tais tratamentos têm o objetivo de garantir a segurança biológica dos alimentos e complementar os programas de autocontrole das indústrias de caráter preventivo, como os cuidados higiênicos na manipulação dos alimentos e na higienização dos equipamentos evitando todo e qualquer tipo de contaminação cruzada. Porém, poucas pesquisas trazem informações conclusivas sobre o fato desses tratamentos promoverem ou não alterações físico-químicas da carne suína, o que seria totalmente indesejável frente a seus parâmetros de qualidade. Assim sendo, o presente projeto se propôs a avaliar as possíveis alterações físico-químicas de pernis suínos submetidos a tratamentos com ácidos orgânicos, vapor e associação dos dois tratamentos. Sendo realizadas análises visuais e sensoriais de aspecto, coloração, consistência e odor, antes e após cada tratamento, bem como, análises físico-químicas visando determinação do percentual de lipídeos, proteínas, pH, umidade e voláteis, também, antes e após cada tratamento. Os resultados obtidos revelaram que os tratamentos utilizados não interferiram nos atributos aspecto, cor, odor e consistência e, também, não alteraram suas propriedades físico-químicas, sendo que, somente o tratamento de vapor associado aos ácidos orgânicos diminuiu o pH e aumentou o teor de umidade e voláteis da carne, porém, não descaracterizou a qualidade físico-química da carne suína, que permaneceu dentro de seus padrões ideais, apta ao consumo humano

Made available in DSpace on 2016-12-08T16:44:49Z (GMT). No. of bitstreams: 1 PGPV15MA176.pdf: 1494826 bytes, checksum: ef728a2a2f60b3d2604505de45449976 (MD5) Previous issue date: 2015-07-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study was carried out to evaluate the effects of apple orchard protection by different anti-hail nets on yield, and physico-chemical and functional quality of the fruits. Maxi Gala and Fuji Kiku8 apple trees were left uncovered, and covered with white, black and red anti-hail nets during the growing seasons of 2013/2014 and 2014/2015, in Vacaria, RS. Black and red nets reduced the photosynthetically active radiation in comparison to white net. Black net reduced yield in Maxi Gala but not in Fuji Kiku 8 apple trees. Black net in Maxi Gala and red net in Fuji Kiku 8 increased the starch-iodine index of the fruit at harvest in comparison to uncovered plants. Black net reduced the soluble solids content and flesh firmness of the fruit at harvest in Maxi Gala , while the red net reduced flesh firmness of the fruit at harvest in Fuji Kiku 8 . In both cultivars, the shading caused by the black net reduced the red color of the fruit (intensity and surface covered with red color), while black and red nets delayed the loss of green background color of the skin. Black and red nets reduced the contents of anthocyanins and phenolic compounds of the skin in Maxi Gala apples but not in Fuji Kiku 8 apples at harvest. The antioxidant activity assessed by DPPH method in the skin tissue of the fruit in both cultivars was also impaired by protecting the orchard with anti-hail nets. The use of anti-hail nets, regardless of color, reduced the phenolic compounds and antioxidant activity in the pulp tissue of Maxi Gala apples, especially after storage. In Fuji Kiku 8 , the orchard protection with white net provided higher values of total phenolic compounds and antioxidant activity, assessed at harvest and after storage in the skin and pulp tissues of the fruit, compared to black net, red net and control. The white net is more suitable for orchard protection in the region of Vacaria than the other nets, by impairing to a less extend the light supply and, therefore, yield and quality of fruits in both cultivars / Este estudo foi conduzido com objetivo de avaliar a influência do uso de telas antigranizo sobre a produção, qualidade físico-química e qualidade funcional em frutos de macieiras cobertas com diferentes telas antigranizo. Foram utilizadas macieiras Maxi Gala e Fuji Kiku8 sem cobertura e cobertas com telas nas cores branca, preta e vermelha, durante as safras 2013/2014 e 2014/2015, em Vacaria, RS. O uso de tela antigranizo nas cores preta e vermelha ocasionou maior redução na radiação fotossinteticamente ativa em relação a tela branca. A tela preta reduziu a produção em macieiras Maxi Gala , mas não em macieiras Fuji Kiku 8 . O uso da tela preta em macieiras Maxi Gala e de tela vermelha em Fuji Kiku 8 aumentou o índice iodo-amido dos frutos em relação às plantas descobertas. A tela preta reduziu o acúmulo de sólidos solúveis e a firmeza de polpa em Maxi Gala , enquanto a tela vermelha diminuiu a firmeza de polpa em maçãs Fuji Kiku 8 . Em ambas as cultivares, o sombreamento ocasionado pela tela preta reduziu a intensidade e a superfície recoberta com vermelho do fruto, enquanto as telas nas cores preta e a vermelha promoveram manutenção da cor de fundo verde. As telas preta e vermelha reduziram o acúmulo de antocianinas e de compostos fenólicos totais na casca de maçã Maxi Gala na colheita, mas não em maçãs Fuji Kiku 8 . A atividade antioxidante, quantificada pelo método DPPH, na casca de ambas as cultivares, também foi reduzida com a cobertura do pomar. O uso de tela antigranizo, independente da cor, reduziu o acúmulo de compostos fenólicos totais e a atividade antioxidante na polpa de maçãs Maxi Gala , principalmente após o armazenamento. Frutos de plantas cobertas com tela branca apresentaram maiores valores de compostos fenólicos totais e atividade antioxidante na casca e polpa de maçãs Fuji Kiku 8 , em relação aos frutos das telas preta e vermelha e do controle, na colheita e após o armazenamento. A tela branca, em relação as demais, é a mais indicada para a cobertura de pomares de maçã na região de Vacaria, por disponibilizar maior radiação as plantas, afetando em menor grau a produção e a qualidade dos frutos, em ambas as cultivares

As estruturas metal-óxido-semicondutor (MOS) são o coração dos transistores de efeito de campo. O estudo e caracterização físico-química desses dispositivos foram a chave para o avanço da tecnologia do Si na indústria microeletrônica. Hoje, a ciência busca novos materiais para a produção de dispositivos de alta mobilidade. Um dos materiais visados é o Ge, pois apresenta mobilidade de cargas superior ao Si (duas vezes para elétrons e quatro vezes para lacunas). Porém, a interface Ge/GeO2 é de natureza reativa, limitando seu uso na construção de tais dispositivos. Muitos esforços têm sido feitos para superar as limitações. Entre eles, encontram-se a passivação da superfície do Ge a partir de solução aquosa de (NH4)2S, previamente a deposição do dielétrico. Outra etapa do processamento desse material na indústria a ser investigada são os tratamentos térmicos posteriores à deposição: a caracterização de estruturas MOS de Pt/HfO2/Ge submetidas a tratamentos térmicos levaram a melhoria das propriedades elétricas. Nesse sentido, o trabalho tem como objetivos investigar o papel da passivação sulfídrica em estruturas dielétrico/Ge e a influência do eletrodo de Pt nas estruturas Pt/HfO2/Ge quando submetidas a tratamentos térmicos. / The heart of field effect transistors is the metal-oxide-semiconductor (MOS) structure. Physico-chemical characterization of the materials employed in such structures enabled the development of Si technology. Nowadays, in order to build high mobility devices, new material are needed. Ge is an alternative material, since its carrier mobilities are higher than those of Si (almost two times for electrons and four times higher for holes). However, the GeO2/Ge interface is not thermally stable, which is a problem for its use on electronic devices. Many attempts to enhance this stability were already investigated. Among them, sulfur passivation of the Ge surface was employed using (NH4)2S aqueous solution prior to the deposition of dielectric layers. Another important step in the fabrication of MOS structures is post-deposition annealing. Pt/HfO2/Ge MOS structures presented improved electrical characteristics following post deposition annealing. The main objectives of this work are to investigate the role of sulfur passivation on dielectric/Ge structures and the influence of Pt electrode in Pt/HfO2/Ge structures submitted to post deposition annealing.