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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Um novo algoritmo de granulometria com aplicação em caracterização de nanoestruturas de silício. / A new correlation-based granulometry algorithm with application in characterizing porous silicon nanomaterials.

Maruta, Ricardo Hitoshi 14 October 2011 (has links)
Granulometria é o processo usado para medir objetos de diferentes tamanhos em imagens de material granular. Frequentemente algoritmos baseados em morfologia matemática ou detecção de arestas são utilizados para esta finalidade. Propomos uma nova abordagem para a granulometria utilizando correlações cruzadas com círculos de tamanhos diferentes. Esta técnica é primeiramente adequada para a detecção de objetos de formato circular, mas pode ser estendido para outras formas utilizando outros núcleos (kernels) de correlação. Experimentos mostram que o novo algoritmo é robusto ao ruído e pode detectar objetos com pouco contraste e/ou com sobreposição parcial. Este trabalho também apresenta características quantitativas estruturais da camada de silício poroso, obtidas aplicando o algoritmo proposto em imagens de microscopia eletrônica de varredura (MEV). O novo algoritmo, que chamamos Granul, calcula as áreas e frequências dos poros. Processamentos adicionais utilizando outros algoritmos classificam os poros em circulares ou quadrados. Relacionamos os resultados quantitativos obtidos com o processo de fabricação e discutimos o mecanismo de formação do poro quadrado no silício. O novo algoritmo mostrou-se confiável no processamento de imagens de MEV e é uma ferramenta promissora para controle no processo de formação dos poros. / Granulometry is the process of measuring the size distribution of objects in an image of granular material. Usually, algorithms based on mathematical morphology or edge detection are used for this task. We propose a entirely new approach for the granulometry using the cross correlations with circles of different sizes. This technique is primarily adequate for detecting circular shaped objects, but it can be extended to other shapes using other correlation kernels. Experiments show that the new algorithm is greatly robust to noise and can detect even faint objects and/or objects with partial superposition. This paper also reports the quantitative structural characteristics of the porous silicon layer based on the proposed algorithm applied to Scanning Electron Microscopy (SEM) images. The new algorithm, that we call Granul, computes the size distribution of pores and classifies the pores in circular or square ones. We relate these quantitative results to the fabrication process and discuss the square porous silicon formation mechanism. The new algorithm shows to be reliable in SEM images processing and is a promising tool to control the pores formation process.
32

Propagação e diferenciação floral do abacateiro /

Oliveira, Inez Vilar de Morais. January 2006 (has links)
Orientador: Antonio Baldo Geraldo Martins / Banca: Dalmo Lopes de Siqueira / Banca: João Alexio Scarpare Filho / Banca: Fabíola Vitti Môro / Banca: Teresinha de Jesus Deléo Rodrigues / Resumo: Esse trabalho teve por objetivo fornecer informações sobre aspectos morfológicos da semente; determinar a possibilidade de clonagem da variedade Duke 7 por alporquia; avaliar influência da época no pegamento da enxertia em abacateiro das variedades 'Hass' e 'Fortuna' e caracterizar, por estudos anatômicos e morfológicos, mudanças na gema vegetativa à florífera, para duas variedades de abacate 'Hass' e 'Fortuna'. As sementes são monoembriônicas e exalbuminosas, de germinação hipógea e a emergência das plântulas ocorreu 33 dias após a semeadura; a raiz primária é longa e de coloração branca e as raízes secundárias são curtas e filiformes; os cotilédones são maciços e de coloração rosada sendo que foi possível observar a presença de múltiplos caulículos na semente de abacate, originados do colo; os frutos são do tipo baga; as sementes apresentam policaulia; o início da estabilização da emergência de plântulas ocorre na oitava semana. Não houve enraizamento dos alporques; o período mais indicado para o sucesso da enxertia, é de modo geral, compreendido entre os meses de novembro e dezembro para ambas as variedades 'Hass' e 'Fortuna'. A transição entre a fase vegetativa e a reprodutiva ocorre no mês de maio, quando há diminuição da temperatura; a evocação floral ocorre um mês após, caracterizado pelo formato arredondado das gemas; a iniciação da inflorescência ocorre dois meses após a transição, no mês de julho. / Abstract: This work aimed to study morphological aspects of seeds; determine the cloning possibility of Duke 7 cultivar by air layering; evaluate the influence of the season on grafting of Hass and Fortuna avocado cultivars and to characterize by anatomical and morphological studies the modifications on vegetative to flowering bud. The seeds are monoembryonic, the germination is hypogea and the emergence of seedlings occurred 33 days after planting; the main root is long, white and the secondary roots are short; the cotiledons are hard and pink; the seeds presented polystems it was observed the presence of many small stems on avocado seed; the fruit is a berry. The stabilization of seed emergency occurred with eight weeks. There was no rooting in the air-Iayerings; the season more indicated for grafting is between November and December for both cultivars. The change from vegetative to reproductive phase was in May, when there is lower temperatures; the floral evocation occurs one month after, characterized by the rounded format of buds; the initiation of the inflorescence occurs after two months of the transition, in July. / Doutor
33

Ocorrência de Pseudomerulius curtisii, Gelatoporia subvermispora e Sarcoporia polyspora no sul do BRASIL / Ocorrence of Pseudomerulius curtisii, Gelatoporia subvermispora and Sarcoporia polyspora on southern Brasil

Baldoni, Daiana Bortoluzzi 20 July 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Pampa is the newest Brazilian biomes. It is one of the lest studied and the one of the most economically exploited. Among these forms of exploitation, there is the cultivation of great dominated grassy fields with exotic forest species. Researches involving animal and plant species have revealed great biodiversity, however, they are still rare for microorganisms. The aim of the study was to collect, to isolate and to analyze morphologically and molecularly three wood-decaying fungi growing on Pinus sp. in Pampa biome: Pseudomerulius curtisii (Berk.) Redhead & Ginns, Gelatoporia subvermispora (Pilat) Niemelä and Sarcoporia polyspora P. Karsten. It was conducted the morphological characterization and the sequencing of ITS1-5.8S-ITS2 of species allowing their identification and phylogenetic comparisons with the literature. P. curtisii calls attention to the rarity and beauty of the basidiome and morphological similarities with specimens of the Northern Hemisphere and Oceania, but with a genetic distance, and may show the geographic isolation and the new taxon to be described. G. subvermispora, widely studied by the high biotechnology and industrial potential. It has high similarity with morphogenetic U.S. specimens, but with genetic divergence of Eurasian specimens. S. polyspora shows high morphological similarity with the specimens of the northern hemisphere, but there is a lack of sequences available for phylogenetic comparison. These species were registered for the first time in South America. P. curtisii, G. subvermispora and S. polyspora, fungi Basidiomycota show high potential for nutrient cycling and soil formation by the capacity or lignin and cellulose degradation. / O Pampa é o mais novo dos biomas brasileiros, sendo o menos estudado e um dos mais explorados comercialmente. Dentre estas formas de exploração, destaca-se o plantio de grandes áreas com espécies florestais exóticas. Os estudos envolvendo espécies animais e vegetais têm revelado grande biodiversidade, mas ainda são escassos para microrganismos. O objetivo deste trabalho foi coletar, isolar e analisar morfológica e molecularmente três fungos decompositores de madeira de Pinus sp. no bioma Pampa: Pseudomerulius curtisii (Berk.) Redhead & Ginns, Gelatoporia subvermispora (Pilát) Niemelä e Sarcoporia polyspora P. Karsten. Efetuou-se a caracterização morfológica e o sequenciamento da região ITS1-5.8S-ITS2 das espécies, permitindo suas identificações e comparações filogenéticas com a literatura. P. curtisii chama atenção pela raridade e beleza dos basidiomas e similaridade morfológica com os espécimes do Hemisfério Norte e Oceania, mas com uma distância genética, podendo mostrar o isolamento geográfico e novo taxon a ser descrito. G. subvermispora, amplamente estudado pelo elevado potencial biotecnológico e industrial, apresenta alta similaridade morfogenética com espécimes dos EUA, porém com divergência genética dos espécimes da Eurásia. S. polyspora apresenta alta similaridade morfológica com os espécimes do hemisfério Norte, mas há falta de sequências disponíveis para comparação filogenética. Essas espécies foram registradas pela primeira vez na América do Sul. P. curtisii, G. subvermispora and S. polyspora (Basidiomycota) apresentam grande potencial para estudos de ciclagem de nutrientes e formação do solo pela capacidade de degradação de lignina e/ou celulose.
34

Um novo algoritmo de granulometria com aplicação em caracterização de nanoestruturas de silício. / A new correlation-based granulometry algorithm with application in characterizing porous silicon nanomaterials.

Ricardo Hitoshi Maruta 14 October 2011 (has links)
Granulometria é o processo usado para medir objetos de diferentes tamanhos em imagens de material granular. Frequentemente algoritmos baseados em morfologia matemática ou detecção de arestas são utilizados para esta finalidade. Propomos uma nova abordagem para a granulometria utilizando correlações cruzadas com círculos de tamanhos diferentes. Esta técnica é primeiramente adequada para a detecção de objetos de formato circular, mas pode ser estendido para outras formas utilizando outros núcleos (kernels) de correlação. Experimentos mostram que o novo algoritmo é robusto ao ruído e pode detectar objetos com pouco contraste e/ou com sobreposição parcial. Este trabalho também apresenta características quantitativas estruturais da camada de silício poroso, obtidas aplicando o algoritmo proposto em imagens de microscopia eletrônica de varredura (MEV). O novo algoritmo, que chamamos Granul, calcula as áreas e frequências dos poros. Processamentos adicionais utilizando outros algoritmos classificam os poros em circulares ou quadrados. Relacionamos os resultados quantitativos obtidos com o processo de fabricação e discutimos o mecanismo de formação do poro quadrado no silício. O novo algoritmo mostrou-se confiável no processamento de imagens de MEV e é uma ferramenta promissora para controle no processo de formação dos poros. / Granulometry is the process of measuring the size distribution of objects in an image of granular material. Usually, algorithms based on mathematical morphology or edge detection are used for this task. We propose a entirely new approach for the granulometry using the cross correlations with circles of different sizes. This technique is primarily adequate for detecting circular shaped objects, but it can be extended to other shapes using other correlation kernels. Experiments show that the new algorithm is greatly robust to noise and can detect even faint objects and/or objects with partial superposition. This paper also reports the quantitative structural characteristics of the porous silicon layer based on the proposed algorithm applied to Scanning Electron Microscopy (SEM) images. The new algorithm, that we call Granul, computes the size distribution of pores and classifies the pores in circular or square ones. We relate these quantitative results to the fabrication process and discuss the square porous silicon formation mechanism. The new algorithm shows to be reliable in SEM images processing and is a promising tool to control the pores formation process.
35

Influence of metal ions on lignin-based carbon fiber quality

Andersson, Sofia January 2017 (has links)
Carbon fiber is a lightweight, versatile material with many current and potential applications. To be able to expand the market for carbon fiber composites in other areas than special applications the production costs must be reduced. One way of accomplishing this could be to use a less expensive raw material where lignin is a good example as it can be provided at lower cost, is renewable and abundantly available compared to commercially used raw materials today. So far, the mechanical properties of lignin-based carbon fibers are inferior relative to commercial carbon fibers. For lignin-based carbon fibers to enter the commercial market more research is necessary to gain knowledge of the conversion of lignin to carbon fiber. The LightFibre project investigates the possibilities to produce carbon fibers based on a mixture of softwood kraft lignin and cellulose. The kraft lignin is isolated from black liquor in the kraft/sulfate process with the LignoBoost process. This master thesis project was conducted within in the LightFibre project and evaluated whether metal ions generally present in kraft lignin had an influence on the final carbon fiber quality in terms of mechanical properties and morphology. The mechanical properties were determined with tensile testing, the morphology by scanning electron microscopy (SEM) and the relative abundance of studied elements with electron dispersive spectroscopy (EDS). The influence of the chosen metal ions was tested by impregnation of dry-jet wet spun prefibers based on 70 wt.% softwood kraft lignin and 30 wt.% dissolving pulp cellulose. The fibers were impregnated in room temperature with solutions containing Na2SO4, K2SO4, MgSO4, FeSO4 and Al2(SO4)3 salts where the cations were the focus in these trials. The concentrations used for impregnation were 0.2 and 1M of the cations. The obtained mechanical properties of the carbon fibers of the samples impregnated with different metal ions did not deviate significantly from the reference which had a tensile strength of 870 MPa and tensile modulus of 68 GPa. The analysis of morphology with SEM showed no defects or damage of any of the fibers. Therefore, it was concluded that the impregnated metal ions: K+, Na+, Al3+, Mg2+ and Fe2+ at the obtained levels in the fibers cause no effects on the fibers during the stabilization and carbonization that affects the mechanical performance of final carbon fiber.  The amount of potassium in one of the samples was estimated to 0.1 wt.%. From the results of this study it may be suggested that the general recommendation of <0.1 wt.% ash in lignin can be exceeded, for dry-jet wet-spun kraft lignin/cellulose-based carbon fibers.
36

Vliv kortikoliberinu a kortikosteronu na poškození hipokampu a jejich vztah ke kognici / The influence of corticosterone and corticoliberin on damage of the hippocampus and their relation to cognition

Řezáčová, Lenka January 2012 (has links)
Dissertation "The influence of corticosterone and corticoliberin on damage of the hippocampus and their relation to cognition" deals with the cognitive, behavioral and histological changes in experimental rat strain long-evans that closer describe the consequences of long-term continuous application of corticoliberin and/or corticosterone. Testing of the behavioral changes was divided into two phases. The first one - within three or fourweeks respectively administration of these hormones, therefore until their early effects - and the second phase - after four weeks of completion of the first phase at the time of the possible late effects. In the twelfth week the experimental animals were killed and in the group which had exogenously elevated corticosterone, the morphological changes in the hippocampus were monitored and measured. In all experimental groups alteration of behavior was observed. Histological and morphological changes in the brain we have found. Layout of experiments in two testing phases allowed differentiation of the early changes and the late and persistent changes. The arrangement of experiments allowed the choice of tests to compare not only individual effects of both hormones (corticoliberin and corticosterone) but also their coactioning and biological responses to them. Using a wider...
37

Jazyk legendy z doby barokní / The Linguistic Characteristics of a Baroque Legend

DOLEŽALOVÁ, Zdeňka January 2008 (has links)
Main topic of this work is to analyze language elements used in the legend from baroque period and that from the complete conception on the gross information contents this work and characteristic features of phonetics and morfology. No research in the field of syntax and lexicology was made at this point (our final work would be to extensive). The complete interpretation refers to father Jiří David´s baroque legend Medicus Hercinius, {\dots} dated 1713. First part we apply to common informations about the author, about the period, in which he lived and wrote his legend, and about his contemporaries. We describe the legendistic literature and conditions to her expansibility in our country, the life of saint Gunther then and the substance of whole David´s work in general. There are important informations about noted humanismus and baroque authors in next two chapters. We describe individual phenomens of two language levels phonetics and morfology then, especially with regard to theory and practice. Principal aim of my work is to contribute to o deeper understanding of Czech language from the late baroque.
38

Jazykový rozbor Cestopisu Bedřicha z Donína / Linguistic analysis of the "Travelbook" by Frederick from Donín

Lehne, Eva January 2011 (has links)
The thesis analyses selected phenomena of graphy, phonology, morfology, lexicology and words-formation of the Frederick from Donin's Czech book of travels, which was written at the turn of the 16th and 17th century. Partly, it also deals with the syntax and style of the work. Selected phenomena of individual language levels are studied using the original manuscript. The thesis intends to show in which aspects the text is close to early modern language usage, and conversely in which aspects it differs from it. The language of the manuscript is also compared with the contemporary Czech language.

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