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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.
81

Armazenamento a baixas temperaturas de diferentes cultivares de bananas: efeito nos atributos de qualidade / Storage at low temperatures of different banana cultivars: effect on quality attributes.

Facundo, Heliofabia Virginia de Vasconcelos 06 May 2013 (has links)
A banana é altamente susceptível a injúrias causadas pelo frio, mas o efeito da refrigeração nos atributos que caracterizam a qualidade do fruto maduro é ainda pouco explorado. Neste trabalho, alguns desses atributos foram analisados em duas cultivares de banana escolhidas por sua diferença em relação à susceptibilidade ao frio: Nanicão e Prata. As duas cultivares foram armazenadas a baixas temperaturas (cv. Nanicão a 13 ºC e cv. Prata a 13 ºC e 10 ºC) por 15 dias e o efeito do frio sobre os compostos voláteis responsáveis pelo aroma e sabor, índices de cor da casca, níveis de carotenoides, açúcares e amido foram analisados comparativamente durante a maturação dos frutos e o perfil de proteínas diferentemente abundantes foi analisado na cultivar Nanicão. Com o auxílio das ferramentas da estatística multivariada, verificou-se que a produção dos compostos voláteis é altamente sensível as baixas temperaturas. A cv. Prata apresentou uma maior resistência ao efeito negativo do armazenamento, mesmo armazenada a 10 ºC. Na cv. Nanicão, as amostras maduras do grupo frio (13 ºC) foram caracterizadas pela presença dos carotenoides majoritários devido ao fato de que as vias metabólicas que utilizam carotenoides terem sido afetadas pelo armazenamento em baixas temperaturas. Para a cv. Prata teve um efeito negativo com o armazenamento, com redução dos níveis de carotenoides tanto a 13 ºC quanto a 10 ºC. Em relação à cor da casca dos frutos não foi observado um efeito evidente nas amostras submetidas a baixas temperaturas. Pela análise proteômica, foi possível entender como o frio causou um impacto negativo na síntese de sacarose, uma vez que as proteínas mais afetadas foram associadas ao metabolismo de energia e de carboidratos. / Bananas are fruits highly susceptible to injuries caused by cold temperatures, but the effect of refrigeration on the attributes that characterize the quality of ripe fruit is still underexplored. In this work, some of these attributes were analyzed in two banana cultivars chosen for their difference in susceptibility to cold temperatures: Nanicão and Prata. Both cultivars were stored at low temperatures (cv. Nanicão at 13 ºC and cv. Prata at 13 °C and 10 °C) for 15 days and the effect of the cold on the volatile compounds responsible for aroma, skin color index, levels of carotenoids, sugars, and starch were comparatively analyzed during fruit maturation and different abundant protein profiles of the Nanicão cultivar were analyzed. By using multivariate statistic tools, it was found that the production of volatile compounds is highly susceptible to low temperatures. However, cv. Prata showed greater resistance to the negative effects of storage even when stored at 10 °C. For cv. Nanicão, ripe samples from the cold group kept at 13 ºC were characterized by the presence of majority carotenoids due to the fact that the metabolic pathways that use carotenoids were affected by the storage at such a low temperature. Conversely, cv. Prata experienced a negative effect with the storage, with reduced levels of carotenoids in both cold groups kept at 13 ºC and 10 ºC. In relation the skin color of the fruit, no effect on the samples held at low temperatures was observed. For proteomics analysis, it was possible to understand how the cold storage caused a negative impact on the synthesis of sucrose, since most of the affected proteins were associated with energy and carbohydrate metabolism.
82

Klassifizierung von Pollenproben mit spektroskopischen und spektrometrischen Methoden und multivariater Statistik

Seifert, Stephan 28 April 2016 (has links)
In dieser Arbeit werden spektroskopische und spektrometrische Methoden diskutiert, um Verfahren auf Grundlage von umfassenden, molekularen Informationen für die Charakterisierung, Klassifizierung und Identifizierung von Pollen zu entwickeln. Es ist bereits bekannt, dass Raman- und Infrarot-Spektroskopie spezifische Fingerabdrücke der chemischen Zusammensetzung von Pollen liefern können. Im Rahmen dieser Arbeit werden nun die oberflächenverstärkte Raman-Streuung (surface-enhanced Raman scattering, SERS), die matrix-assisted laser desorption/ionisation time-of-flight-Massenspektrometrie (MALDI-TOF MS) und die Fourier-Transform-Infrarot-Spektroskopie (FTIR-Spektroskopie) einzelner Pollenkörner für die taxonomische Klassifizierung eingesetzt. Neben der Anwendung zur taxonomischen Klassifizierung können spektroskopische und spektrometrische Methoden auch zur Erkennung von Unterschieden, die durch Umwelteinflüsse verursacht werden, eingesetzt werden. Als ein erstes Beispiel dieser Anwendung werden cherry leaf roll virus (CLRV) infizierte Birkenpollen untersucht und mit Pollen von Kontrollpflanzen verglichen. Die Ergebnisse dieser Arbeit zeigen, dass spektroskopische und spektrometrische Methoden vielversprechend für die Pollenanalytik in vielen verschiedenen Forschungsgebieten sind. / The investigation of pollen grain samples for characterization, classification and identification is still an analytical task that is both challenging and time-consuming, since it is mainly based on the morphological characteristics of the pollen grains. In order to develop approaches that are based on extensive molecular information and that lead to an automated classification, in this thesis, a combination of spectroscopic and spectrometric tools is discussed. It is already known that a fingerprint analysis of the chemical composition of pollen samples can be accomplished by Raman and infrared spectroscopies. Here, surface-enhanced Raman scattering (SERS), matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS), and Fourier transform infrared (FTIR) spectroscopy of single pollen grains are successfully applied for the taxonomic classification of pollen samples. In addition to the application for taxonomic classification, it is conceivable that spectroscopic and spectrometric data could also be used to investigate chemical changes caused by environmental influences. As a first example for such an application, cherry leaf roll virus (CLRV) infected birch pollen are investigated and compared to samples from control plants. The results in this work indicate that spectroscopic and spectrometric methods are powerful analytical tools that may be useful for improved pollen investigation in different areas of research.
83

Avaliação institucional no ensino superior: aspectos instituintes

Musis, Carlo Ralph de 01 December 2006 (has links)
Made available in DSpace on 2016-04-28T20:57:10Z (GMT). No. of bitstreams: 1 Carlo Ralph de Musis.pdf: 534050 bytes, checksum: 0792c172fe0da8a05cdb9ab7d8e60b9a (MD5) Previous issue date: 2006-12-01 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work researched and reflected about the possibility of developing a process of evaluation in Higher Education Institutions by the meanings developed by the people who belong to them. At first, the construction of this process implies in the interpretation of the Higher Education Institutions as a group that is at the same time formal, contradictory and dialogic. In the conceptual plan, the concept of judgment and enlightenment was developed in Immanuel Kant e Hannah Arendt s perspective, followed by the reflections done by Theodor W. Adorno to the Kantian categorical imperative. Finally, the sociological model developed by Pierre Bourdieu was used to understand the complex that the individuals that are being studied use to structure their actions, defined the line that would be followed in this evaluation and, according to the specificities of the locus, demanded the use of different instruments, in this case: questionnaires, observation and interviews (individually and in group). Analyses of the content based on associated and implicative figure, multidimensional stagger and non parametric correlation were done. From this comparison a statement was made that the Higher Education Institution used in the research had a behavior in which the heteronomy, on the one hand, establishes components that make the educational process more difficult and spreads discourses guided by the clichés, and on the other hand, shows a complex with potential for the free knowledge and practices / Este trabalho pesquisou e refletiu sobre a possibilidade de desenvolver um processo avaliativo em instituições de ensino superior tendo em vista as significações desenvolvidas pelas suas populações instituintes. Partiu da compreensão de que a construção deste processo implica na interpretação de Instituições de Ensino Superior como um complexo concomitantemente formal, contraditório e dialógico. No plano conceitual, trabalhou o conceito de juízo e esclarecimento na perspectiva de Immanuel Kant e Hannah Arendt, seguido das ponderações feitas por Theodor W. Adorno ao imperativo categórico kantiano. Por fim, utilizou o modelo sociológico desenvolvido por Pierre Bourdieu para apreender o complexo que os indivíduos estudados utilizam para estruturar suas ações, definiu o fio da meada desta avaliação e, conforme as especificidades do locus, exigiu o uso de diferentes instrumentos, no caso, questionários, observação e entrevistas (individuais e em grupo). As análises de conteúdo feitas tiveram apoio em estatística coesitiva e implicativa, escalonamento multidimensional e correlação não paramétrica. Desse confronto foi possível construir o argumento de que a instituição de ensino superior pesquisada possuía uma prática em que a heteronomia, por um lado, instaura componentes que criam entraves ao processo educativo e difunde discursos orientados a clichês e, por outro, deixa entrever um complexo com potencial para conhecimentos e práticas emancipatórias
84

Um ensaio metodológico sobre a qualidade de vida no distrito de Cachoeirihna, zona norte da cidade de São Paulo / An methodological essay about the quality of life in the Cachoeirinha district, northen of São Paulo city - SP

Roggero, Marilia Araujo 25 August 2009 (has links)
A qualidade de vida urbana tem sido estudada pelas mais diversas áreas do conhecimento e é uma temática complexa. O tema qualidade de vida envolve questões multidisciplinares apresentadas por meio de perspectivas diferenciadas, de acordo com a relevância do momento histórico, das condições sociais, bem como da ideologia dominante a partir dos objetivos propostos. Isso posto, a abordagem adotada no presente estudo está focada na satisfação das necessidades básicas da população, de modo a garantir o pleno desenvolvimento físico, mental e social. Para isso, foram abordadas quatro dimensões: condições de saneamento, situação socioeconômica e demografia, por meio da utilização dos dados censitários (IBGE, 2000) e as zonas residenciais homogêneas, por meio de técnicas de interpretação de imagens de satélite com alta resolução espacial. Para a espacialização e processamento dos dados quantitativos e qualitativos foram utilizadas técnicas de Geoprocessamento, por meio do uso de um Sistema de Informação Geográfica e técnicas estatísticas, que garantiram a distribuição espacial dos dados levantados. A partir dos resultados alcançados por meio dessas técnicas, foi possível elaborar o mapa síntese da qualidade de vida do distrito da Cachoeirinha, zona norte da cidade de São Paulo. / The quality of urban life has been studied in various areas of academic specialization and is a complex theme. The subject\'s quality of life involves multi-disciplinary questions presented with different perspectives, according to the relevance of the historical moment, social conditions, as well as the dominant ideology shaping the objectives in question. The approach adopted in the present study is focused on the satisfaction of the basics needs of the population, in order to guarantee complete physical, mental and social development. For this, four dimensions were considered: conditions of sanitation; the socioeconomic situation and demography; using data of the last demographic Census in 2000 (IBGE, 2000); and homogeneous residential zones, by means of technical interpretation of satellite images with high spatial resolution. For the spatial results and processing of quantitative and qualitative data, techniques of Geoprocessing had been used, using Geographic Information System and statistical techniques, which had guaranteed the spatial distribution of the listed data. From the results obtained with these techniques, it was possible to elaborate the map synthesis of the quality of life of Cachoeirinha District, northern zone of São Paulo, Brazil.
85

Zebrafish como organismo-modelo para análises de efeitos comportamentais e toxicológicas da cetamina empregando cromatografia em fase gasosa e estatística multivariada / Zebrafish as an organism-model for analysis of behavioral effects and toxicological analysis of ketamine employing gas chromatography and multivariate statistics

Campos, Eduardo Geraldo de 11 March 2016 (has links)
A cetamina é uma droga amplamente utilizada e o seu uso inadequado tem sido associado à graves consequências para a saúde humana. Embora as propriedades farmacológicas deste agente em doses terapêuticas sejam bem conhecidas, existem poucos estudos sobre os efeitos secundários induzidos por doses não-terapêuticas, incluindo os efeitos nos estados de ansiedade e agressividade. Neste contexto, os modelos animais são uma etapa importante na investigação e elucidação do mecanismo de ação a nível comportamental. O zebrafish (Danio rerio) é um novo organismo-modelo, interessante e promissor, uma vez que apresenta alta similaridade fisiológica, genética e neuroquímica com seres humanos, respostas comportamentais bem definidas e rápida absorção de compostos de interesse em meio aquoso além de apresentar uma série de vantagens em relação aos modelos mamíferos tais como manutenção de baixo custo, prática e executável em espaços reduzidos. Nesse sentido, faz-se necessário a execução de ensaios comportamentais em conjunto com análises estatísticas robustas e rápidas tais como ANOVA e Métodos Multivariados; e também o desenvolvimento de métodos analíticos sensíveis, precisos e rápidos para determinação de compostos de interesse em matrizes biológicas provenientes do animal. Os objetivos do presente trabalho foram a investigação dos efeitos da cetamina sobre a ansiedade e a agressividade em zebrafish adulto empregando Testes de Claro-Escuro e Testes do Espelho e métodos estatísticos univariados (ANOVA) e multivariados (PCA, HCA e SIMCA) assim como o desenvolvimento de método analítico para determinação da cetamina em matriz biológica proveniente do animal, empregando Extração Líquido-Líquido e Cromatografia em Fase Gasosa acoplada ao Detector de Nitrogênio-Fósforo (GC-NPD). Os resultados comportamentais indicaram que a cetamina produziu um efeito significativo dose-dependente em zebrafish adulto na latência à área clara, no número de cruzamentos entre as áreas e no tempo de exploração da área clara. Os resultados das análises SIMCA e PCA mostraram uma maior similaridade entre o grupo controle e os grupos de tratamento expostos às doses mais baixas (5 e 20 mg L-1) e entre os grupos expostos às doses de 40 e 60 mg L-1. Na análise por PCA, dois componentes principais responderam por 88,74% de toda a informação do sistema, sendo que 62,59% da informação cumulativa do sistema foi descrito pela primeira componente principal. As classificações HCA e SIMCA seguiram uma evolução lógica na distribuição das amostras por classes. As doses mais altas de cetamina induziram uma distribuição mais homogênea das amostras enquanto as doses mais baixas e o controle resultaram em distribuições mais dispersas. No Teste do Espelho, a cetamina não induziu efeitos significativos no comportamento dos animais. Estes resultados sugerem que a cetamina é modulador de comportamentos ansiosos, sem efeitos indutores de agressividade. Os resultados da validação do método cromatográfico indicaram uma extração com valores de recuperação entre 33,65% e 70,89%. A curva de calibração foi linear com valor de R2 superior a 0,99. O limite de detecção (LOD) foi de 1 ng e o limite de quantificação (LOQ) foi de 5 ng. A exatidão do método cromatográfico manteve-se entre - 24,83% e - 1,258%, a precisão intra-ensaio entre 2,67 e 14,5% e a precisão inter-ensaio entre 1,93 e 13,9%. / Ketamine is a widely used drug and its inappropriate use has been associated with serious consequences for human health. Although the pharmacological properties of this agent in therapeutic doses are well known, there are few studies about the side effects induced at non-therapeutic doses, including the effects on states of anxiety and aggression. In this context, animal models are an important step in the investigation and elucidation of the mechanism of action at the behavioral level. The zebrafish (Danio rerio) is a new organism model, interesting and promising, since it presents high physiological, genetics and neurochemistry similarity in relation to humans, well-defined behavioral responses and rapid absorption of interesting compounds in an aqueous medium, apart from presents several advantages over mammalian models such as practical, low cost maintenance and executable in reduced spaces. In this sense, it is necessary to perform behavioral tests in conjunction with robust and rapid statistical analysis such as ANOVA and multivariate methods; and also the development of sensitive, accurate and rapid analytical methods to determination of compounds of interest in biological matrices from the animal. The objectives of this study were to investigate the effects of ketamine on anxiety and aggression in adult zebrafish using Light-Dark and Mirror Biting tests and univariate (ANOVA) and multivariate (PCA, HCA and SIMCA) statistical methods and to develop an analytical method for determination of ketamine in biological animal matrices using Liquid-Liquid Extraction and Gas Chromatography coupled with Nitrogen-Phosphorus Detector (GC-NPD). The behavioral results of Light-Dark Test indicated that ketamine produced a significant dose-dependent response in the latency to light area, in the number of midline crossings and in the time spent in light area. Results of SIMCA and PCA analysis showed a greater similarity between the control group and treatment groups exposed to lower doses (5 and 20 mg L-1) and between the treatment groups at doses of 40 and 60 mg L-1. In the analysis PCA, two principal components accounted for 88,74% of all the system information and 62,59% of the cumulative information of the system were described for the first principal component. The HCA and SIMCA results showed a logical evolution in the distribution of samples per class. The higher dose of ketamine induced a more homogeneous distribution of the samples while the lower doses and control resulted in more dispersed distribution. In the Mirror Test, ketamine induced no significant effect on the behavior of animals. These results suggest that ketamine is a modulator of anxious behavior without inducing aggressive effects. The results of the validation of chromatographic method indicated an extraction with recovery ranged between 33,65% to 70,89%. Calibration curve was linear with R2 value higher than 0,99. The limit of detection (LOD) was 1 ng and the limit of quantification (LOQ) was 5 ng. The accuracy of gas chromatographic method ranged between - 24,83% and - 1,258%, intra-assay precision between 2,67 and 14,5% and inter-assay precision between 1,93 and 13,9%.
86

Diversidade genética entre cultivares de Mandioca da Região Oeste do Paraná / Morphological and genetic diversity among cultivars of cassava Western Paraná

Egewarth, Jonas Francisco 26 February 2014 (has links)
Made available in DSpace on 2017-07-10T17:36:53Z (GMT). No. of bitstreams: 1 2014_Diss_Jonas_Francisco_Egewarth.pdf: 723125 bytes, checksum: 682d564ae8329cf87ce6675a399a243d (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present study was conducted to evaluate the genetic diversity through quantitative and qualitative morphological characteristics in cassava cultivars used by farmers in western region of Paraná State. For both 24 cassava genotypes were collected, and they are subjected to experimental testing conducted in the municipality of Marechal Candido Rondon in the agricultural year 2012/2013. The field trial was implemented following the randomized complete block design with three replications in area situated 24 33 ' south latitude and 54 31' west longitude, and altitude of 420 m. The genetic diversity was performed with the qualitative characters (21 descriptors) and then quantitative (9 descriptors). After tabulating the data was performed obtaining the Euclidean distance matrix for the qualitative and quantitative characteristics for the Mahalanobis and then made up the clustering structure by Tocher methods, UPGMA and nearest neighbor for each array away, with the data quality characteristics also employed the method of Tocher optimization. For qualitative characteristics was found that genotypes Fécula Branca, Cascuda 6, Baianinha 2 and 3 were different from other genotypes of their varieties, existing variability among these varieties or specimens, these examples do not correspond to their respective manifolds. Genotypes Vermelha Uma Rama 1 and 2 were split in all methods, demonstrating that they have inter-variability, evaluated for quality characteristics, not being from the same genetic material. With the data of quantitative traits was found that the genotype of Fécula Branca 3 was different from the other genotypes of the same nomenclature. The other genotypes fécula branca presented in the same group, along with the genotypes of husky. Genotypes Vermelha Uma Rama 1 and 2 were split in all methods, demonstrating that they possess variability among themselves, the set of traits. The Baianinha 1 genotype was different from Baianinha genotypes 2 and 3, showing the existence of variation between them for traits / O presente trabalho foi conduzido para avaliar a diversidade genética através de características morfológicas quantitativas e qualitativas em cultivares de mandioca utilizadas por agricultores da região Oeste do Estado do Paraná. Para tanto foram coletados 24 genótipos de mandioca, sendo os mesmos submetidos a um ensaio experimental conduzido no município de Marechal Cândido Rondon, no ano agrícola 2012/2013. O ensaio de campo foi implantado seguindo o delineamento de blocos ao acaso com três repetições em área situada a 24o 33 de latitude Sul e 54o 31 de longitude Oeste, tendo altitude média de 420 m. A avaliação da diversidade genética foi realizada com os caracteres qualitativos (21 descritores) e depois com os quantitativos (9 descritores). Após a tabulação dos dados realizou-se a obtenção da matriz de distância euclidiana para as características qualitativas e de Mahalanobis para os quantitativos e, em seguida, realizou-se o agrupamento dos genótipos pelos métodos de Tocher, UPGMA e Vizinho mais próximo para cada matriz de distância, com os dados das características qualitativas também empregou-se o método de Otimização de Tocher. Pelas características qualitativas se verificou que os genótipos de Fécula Branca 6, Cascuda 3 e Baianinha 2 foram diferentes dos demais genótipos de suas variedades, existindo variabilidade dentre os exemplares destas variedades ou ainda, estes não correspondem a exemplares de suas respectivas variedades. Os genótipos Vermelha Uma Rama 1 e 2 foram agrupados separadamente em todos os métodos, evidenciando que os mesmos possuem variabilidade entre si, para as características qualitativas avaliadas, não sendo pertencentes ao mesmo material genético. Com os dados das características quantitativas se verificou que o genótipo de Fécula Branca 3, foi diferente dos demais genótipos de mesma nomenclatura. Os demais genótipos de fécula branca se apresentaram no mesmo grupo, juntamente aos genótipos de cascuda. Os genótipos Vermelha Uma Rama 1 e 2 foram agrupados separadamente em todos os métodos, evidenciando que os mesmos possuem variabilidade entre si, para o conjunto de características avaliadas. O genótipo Baianinha 1 foi diferente dos genótipos Baianinha 2 e 3, evidenciando a existência de variação entre os mesmos para as características avaliadas
87

Etude de la microstructure et des performances des revêtements céramiques YSZ finement structurés obtenus par projection plasma de suspension / Study of the microstructure and efficiency of YSZ-SPS finely structured ceramic coatings

Zhao, Yongli 25 September 2018 (has links)
Grâce à l'utilisation d'un porteur liquide, la projection plasma de suspension (SPS) permet la fabrication de revêtements finement structurés. Comme pour la projection plasma conventionnelle (APS), les microstructures des revêtements SPS peuvent être adaptées en contrôlant les conditions de projection. Cependant, le procédé SPS est plus compliqué que le procédé APS par son nombre de paramètres modifiables.Cette thèse vise à apporter une compréhension plus fondamentale de la relation entre les paramètres du procédé SPS et les propriétés des revêtements YSZ en identifiant des modèles génériques basés sur l’utilisation de méthodes statistiques mathématiques pour l'étude de l'influence et de la sensibilité de paramètres individuels.Des expériences systématiques ont été menées pour étudier l'influence de six paramètres (puissance du plasma, charge massique de suspension, taille de la poudre, distance de projection, pas de projection et rugosité du substrat) sur la microstructure des revêtements qui ont aussi été analysés en terme de propriétés d’usage (mécanique, thermique, tribologique, etc.). La porosité des revêtements a fait l’objet d’une étude approfondie et les mesures ont été réalisées par trois techniques différentes : la méthode par analyse d’images, la transmission RX et la méthode USAXS (Ultra-Small Angle X-ray Scattering). Des analyses multivariées sur les données expérimentales recueillies ont été effectuées et plusieurs modèles mathématiques ont été proposés afin de prédire les propriétés des revêtements et guider ensuite vers une optimisation de la microstructure du revêtement en vu d'applications spécifiques.Dans ce contexte d'optimisation des performances mécaniques et tribologiques de ces revêtements céramiques, différentes quantités et tailles de poudre h-BN ont été ajoutées dans la suspension YSZ. Les revêtements composites YSZ / h-BN ont été fabriqués et leur analyse a montré une nette réduction du coefficient de frottement et du taux d'usure lorsque la taille et la quantité de poudre d’ajout sont optimisées l'une avec l'autre. Trois mécanismes d’usure ont finalement été identifiés et seront discutés. / Thanks to the using of liquid carrier, suspension plasma spray (SPS) enables the manufacture of finely structured coatings. As for conventional plasma spraying (APS), the microstructures of SPS coatings can be tailored by controlling the spray conditions. However, SPS is more complicated than APS due to its number of modifiable parameters.This thesis aims to provide a more fundamental understanding of the relationship between SPS process parameters and the properties of YSZ coatings by identifying generic models based on the use of mathematical statistical methods for the study of influence and sensitivity of the individual parameters.Systematic experiments were carried out to study the influence of six parameters (plasma power, suspension mass load, powder size, projection distance, projection step and substrate roughness) on the microstructure of coatings which were also analyzed in terms of the properties (mechanical, thermal, tribological, etc.). The porosity of the coatings was studied in detail and the measurements were carried out using three different techniques: the image analysis method, the X-ray transmission and the USAXS (Ultra-Small Angle X-ray Scattering) method. Multivariate analyzes of the collected experimental data were performed and several mathematical models were proposed to predict the properties of the coatings and then guide towards an optimization of the microstructure of the coating for specific applications.In this context of optimizing the mechanical and tribological performance of ceramic coatings, different amounts and sizes of h-BN powder have been added in the YSZ suspension. The YSZ/h-BN composite coatings were manufactured by SPS process and their analysis showed a clear reduction in the coefficient of friction and the wear rate when the size and the amount of addition powder are optimized together. Three wear mechanisms have finally been identified and been discussed.
88

Aspects of locomotor evolution in the Carnivora (Mammalia)

Andersson, Ki January 2003 (has links)
<p>In this thesis, the shape of the distal humerus trochlea is analysed using landmark-based morphometrics and multivariate methods, with the aim of exploring locomotor evolution in carnivorans. Elbow joint morphology is used together with body size and craniodental morphology to characterize past and present carnivorans. Evolutionary implications are studied at the ordinal, familial, and species levels, testing specific hypotheses about scaling, morphological constraints, evolutionary trajectories, and potential for social pack-hunting behaviour. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and appears to scale similarly throughout the order Carnivora. A general predictive model for carnivoran bodymass is presented (a=0.601; b= 2.552; r2=0.952, SEE=0.136, p<0001, n=92), which removes the need for the investigator to actively choose between the diverging estimates that different predictors and their equations often produce. At the elbow joint, manual manipulation and locomotion appear to be conflicting functions, thus suggesting mutually exclusive lifestyles involving either forelimb grappling or pursuit. At large body sizes, carnivorans are distributed over a strongly dichotomised pattern (grappling or locomotion), a pattern coinciding with the postulated threshold in predator-prey size ratio at 21.5-25 kg. This pattern is compared to that of two carnivoran faunas from the Tertiary. In the Oligocene (33.7-23.8 Myr BP), the overall pattern is remarkably similar to that observed for extant Carnivora. In the Miocene (23.8-11.2 Myr BP) carnivores show a similarly dichotomised pattern as the Oligocene and Recent, although the whole pattern is shifted towards larger body sizes. This difference is suggested to be a reflection of the extraordinary species richness of browsing ungulates in the early Miocene of North America. Such an increase in prey spectrum would create a unique situation, in which large carnivores need not commit to a cursorial habitus in order to fill their nutritional requirements. Finally, the elbow joints and craniodental morphology (14 measurements) of fossil canids were examined with the aim of assessing the potential for pack-hunting in fossil canids. It is clear that small and large members of the Recent Caninae share similar craniodental morphologies. However, this pattern is not present in Borophaginae and Hesperocyoninae. In the latter, large representatives are characterized by being short-faced, with reduced anterior premolars and enlarged posterior premolars, thus approaching a “pantherine-like” craniodental configuration. These traits are interpreted as an adaptation for killing prey with canine bites. It is similarly determined that, unlike recent Caninae, all analyzed species of borophagines and hesperocyonines have retained the ability to supinate their forearms. It is therefore likely that manual manipulation was part of their hunting behaviour, thus removing an essential part of the argument for social pack-hunting in these forms, as the benefits of such a strategy become less obvious.</p>
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Aspects of locomotor evolution in the Carnivora (Mammalia)

Andersson, Ki January 2003 (has links)
In this thesis, the shape of the distal humerus trochlea is analysed using landmark-based morphometrics and multivariate methods, with the aim of exploring locomotor evolution in carnivorans. Elbow joint morphology is used together with body size and craniodental morphology to characterize past and present carnivorans. Evolutionary implications are studied at the ordinal, familial, and species levels, testing specific hypotheses about scaling, morphological constraints, evolutionary trajectories, and potential for social pack-hunting behaviour. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and appears to scale similarly throughout the order Carnivora. A general predictive model for carnivoran bodymass is presented (a=0.601; b= 2.552; r2=0.952, SEE=0.136, p&lt;0001, n=92), which removes the need for the investigator to actively choose between the diverging estimates that different predictors and their equations often produce. At the elbow joint, manual manipulation and locomotion appear to be conflicting functions, thus suggesting mutually exclusive lifestyles involving either forelimb grappling or pursuit. At large body sizes, carnivorans are distributed over a strongly dichotomised pattern (grappling or locomotion), a pattern coinciding with the postulated threshold in predator-prey size ratio at 21.5-25 kg. This pattern is compared to that of two carnivoran faunas from the Tertiary. In the Oligocene (33.7-23.8 Myr BP), the overall pattern is remarkably similar to that observed for extant Carnivora. In the Miocene (23.8-11.2 Myr BP) carnivores show a similarly dichotomised pattern as the Oligocene and Recent, although the whole pattern is shifted towards larger body sizes. This difference is suggested to be a reflection of the extraordinary species richness of browsing ungulates in the early Miocene of North America. Such an increase in prey spectrum would create a unique situation, in which large carnivores need not commit to a cursorial habitus in order to fill their nutritional requirements. Finally, the elbow joints and craniodental morphology (14 measurements) of fossil canids were examined with the aim of assessing the potential for pack-hunting in fossil canids. It is clear that small and large members of the Recent Caninae share similar craniodental morphologies. However, this pattern is not present in Borophaginae and Hesperocyoninae. In the latter, large representatives are characterized by being short-faced, with reduced anterior premolars and enlarged posterior premolars, thus approaching a “pantherine-like” craniodental configuration. These traits are interpreted as an adaptation for killing prey with canine bites. It is similarly determined that, unlike recent Caninae, all analyzed species of borophagines and hesperocyonines have retained the ability to supinate their forearms. It is therefore likely that manual manipulation was part of their hunting behaviour, thus removing an essential part of the argument for social pack-hunting in these forms, as the benefits of such a strategy become less obvious.
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Geotechnical Aspects of Buildings on Expansive Soils in Kibaha, Tanzania

Lucian, Charles January 2008 (has links)
The focus of this study is on potential damages to buildings resulting from expansive soils in Tanzania, particularly clay soils in Kibaha. For the fact that most of the affected structures are founded on expansive soils, a clear understanding of the behaviour of soils and their interaction with structures has been of interest to the study in order to evaluate properly the source of the problem.The geotechnical behaviour of expansive clay soils is investigated by looking into the geomorphologic, geological and climatic conditions and mineralogical composition of the soils in the study area.Two sites, representative of known problem-areas in Kibaha were selected for geotechnical tests. Geotechnical site investigation consisted of open trial pits, profile description and the collection of both disturbed and undisturbed samples. To extend and amplify the findings, supplementary samples were collected from the environs of the two sites.The collected samples were submitted to soil laboratories at KTH, ARU, SEAMIC and DIT for mineralogical composition tests, natural water content, density, Atterberg limits and swell tests. The results of this investigation indicate that soils in Kibaha contains clay (31%), have high liquid limit (59%) and plastic limit (37%) which indicate high potential swell.Since swell pressure, free swell and swell percent are key properties of expansive soils, the swell properties were measured by free swell tests and one-dimensional oedometer swell tests. The free swell ranged from 100% to 150% and the swell pressure was in the region of 45 kPa. The coefficient of linear extensibility (COLE) was determined for characterizing expansive clays. For all tested samples, COLE ranged from 0.09 to 0.14 indicating that soils fall in the region of high to very high expansion potential rating. The properties of expansive soils were confirmed by the x-ray diffraction test which showed the presence of smectite in the soil. Furthermore, total suction measurement technique using filter paper method indicated that the soils have high suction values, signifying that they have a tendency to swell upon wetting depending on plasticity of particular soil.The depth of the active zone was measured as a function of moisture variations in the profiles during two extreme weather conditions. The active zone depth was found to be between 1.0 and 2.0 m deep. Procedures to assess models to predict swell in the case study were outlined together with their validity.Vertical and horizontal spatial variability in selected soil properties was defined using geostatistical techniques through the fitting of variogram. The indicator semivariograms of both clay contents and free swell gave a range of 20 m horizontally and 1.0 m vertically, with the horizontal variograms exhibiting greater ranges than the dipping variograms.Physical conditions of the surveyed properties in the area confirmed that building damages are associated with poor building materials triggered by expansive soils. In support of the obtained data, the actual behaviour of the foundations was supplemented with prototypes of strip foundations whose performances were monitored over a period of four months. Finally, suggested are the ways forward to solve the problem of foundation on expansive soil / QC 20100824

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