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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.
1

Stomatopoda (Crustacea - Hoplocarida) no nordeste brasileiro: morfometria como ferramenta taxonômica.

Silva, Jonathas Barreto Pessoa 25 February 2011 (has links)
Made available in DSpace on 2015-04-17T14:55:22Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4231010 bytes, checksum: 987dfa120393735b7344d81940380518 (MD5) Previous issue date: 2011-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The stomatopods are a marine criptobenthic crustacean order inhabiting tropical and subtropical waters. Their main characteristic is the augmented second pair of maxilipeds which are used as both tools and weapons. In the present work twenty species of stomatopods from the northeastern brazilian coast had been morphometrically studied and a species catalog was produced. Structural patterns were observed and described within the families and species. Maximum or minimum sizes of four species have been raised: Pseudosquillisma oculata; Lysiosquilla scabricauda; Alachosquilla floridensis and Gibbesia neglecta. Most cases showed that it is possible distinguishing among different taxons using six linear morphometric measurements through discriminant analyses. No significant morphometric differences between males and females were detected within the analysed species. Key words: stomatopods, brazilian northeast, morphometry, catalog, structural patterns. / Os estomatópodes compõe uma ordem de crustáceos marinhos criptobentônicos que habitam águas tropicais e subtropicais. A principal característica destes animais é o segundo par de maxilípedes aumentados que são utilizados tanto como ferramenta quanto arma. No presente trabalho vinte espécies de estomatópodes do litoral nordestino brasileiro foram estudadas morfometricamente e foi feito um catálogo de espécies. Foram observados e descritos padrões estruturais característicos das famílias e espécies. Os tamanhos mínimos ou máximos de quatro das espécies estudadas foram ampliados: Pseudosquillisma oculata; Lysiosquilla scabricauda; Alachosquilla floridensis e Gibbesia neglecta. Foi possível, na maioria dos casos, distinguir diferentes táxons utilizando seis características morfométricas lineares através de análises discriminantes. Não foram encontradas diferenças morfométricas significativas entre machos e fêmeas nas espécies analisadas.
2

Modeling and Analysis of Wave and Damaging Phenomena in Biological and Bioinspired Materials

Nicolas Guarin-Zapata (6532391) 06 May 2021 (has links)
<p> There is a current interest in exploring novel microstructural architectures that take advantage of the response of independent phases. Current guidelines in materials design are not just based on changing the properties of the different phases but also on modifying its base architecture. Hence, the mechanical behavior of composite materials can be adjusted by designing microstructures that alternate stiff and flexible constituents, combined with well-designed architectures. One source of inspiration to achieve these designs is Nature, where biologically mineralized composites can be taken as an example for the design of next-generation structural materials due to their low density, high-strength, and toughness currently unmatched by engineering technologies.</p><p><br></p> <p>The present work focuses on the modeling of biologically inspired composites, where the source of inspiration is the dactyl club of the Stomatopod. Particularly, we built computational models for different regions of the dactyl club, namely: periodic and impact regions. Thus, this research aimed to analyze the effect of microstructure present in the impact and periodic regions in the impact resistance associated with the materials present in the appendage of stomatopods. The main contributions of this work are twofold. First, we built a model that helped to study wave propagation in the periodic region. This helped to identify possible bandgaps and their influence on the wave propagation through the material. Later on, we extended what we learned from this material to study the bandgap tuning in bioinspired composites. Second, we helped to unveil new microstructural features in the impact region of the dactyl club. Specifically, the sinusoidally helicoidal composite and bicontinuous particulate layer. For these, structural features we developed finite element models to understand their mechanical behavior.</p><p><br></p> <p>The results in this work help to elucidate some new microstructures and present some guidelines in the design of architectured materials. By combining the current synthesis and advanced manufacturing methods with design elements from these biological structures we can realize potential blueprints for a new generation of advanced materials with a broad range of applications. Some of the possible applications include impact- and vibration-resistant coatings for buildings, body armors, aircraft, and automobiles, as well as in abrasion- and impact-resistant wind turbines.</p><br>

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