This Diploma Thesis has been written and defended at the Université Catholique de Lyon in France under the Double Degree Agreement between the Czech University of Life Sciences Prague, and the Université Catholique de Lyon. In accordance with the Double Degree Agreement, this Diploma Thesis is fully recognized as part of the MSc programme study at the Czech University of Life Sciences Prague.

Chemistry of intermetallic bonded diamond is studied. The impact resistance and energies of intermetallic bonded diamond is compared to current poly crystalline diamond compacts. IBD’s are found to have high standards of hardness and have more impact energies absorbed. Intermetallic bonded diamond composite comprises of diamond particles dispersed in Tungsten carbide using Nickel aluminide (Ni3Al) as binder. In previous research conducted on IBD’s, diamonds are successfully dispersed in intermetallic alloy of nickel aluminide and processed at 1350°C such that diamond particles remain intact without forming graphite. Composites are formed by milling, pressing the intermetallic binder and diamond particles and sintering at high temperature conditions.

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In this investigation the effects of material, structural and testing parameters of carbon epoxy braided composite tubes were analysed with respect to their performance in crush and impact conditions. An original method of manufacturing the composite tubes with vacuum infusion together with an expandable foam core to form multi-cellular structures was used. Low cost, 24k tow carbon fibre braids were used and their performance was compared with that of the more expensive l2k tow size fibres. The specimens produced were axially crushed at constant quasi-static low velocities and at higher impact velocities using an instrumented falling weight machine. Load displacement data gathered from such tests were used to evaluate the test specimens with respect to their specific energy absorption values. The effects of a number of parameters including fibre tow size, braid architecture, resin content and loading type were evaluated. From the experimental results analysed from the test specimens it can be concluded that: - The 24k fibre showed lower specific energy absorption values than specimens made from l2k fibre. Epoxy resin content rather than epoxy resin type can significantly affect the specific energy absorption values. In general, specimens tested in impact loading exhibited lower specific energy absorption values than the same specimens test in quasi-static crush. A reasonably good correlation between global density and specific energy absorption for the type of structures examined was found

Made available in DSpace on 2014-06-12T17:21:10Z (GMT). No. of bitstreams: 2 arquivo5983_1.pdf: 449605 bytes, checksum: 2508f2b8b7eb0a3464c288841ed2c43a (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2005 / Esta dissertação estuda a indústria do camarão cultivado em cativeiro no Brasil. Esta atividade atingiu na década de 90 a marca 7,3 ton/ha/ano, com estimativas de atingir uma produção superior a 300 mil ton em 2010, gerando uma receita de exportação superior a US$ 1 bilhão conforme Associação Brasileira de Criadores de Camarão (ABCC, 2004). A carcinicultura tornou-se uma atividade geradora de empregos e divisas para o nordeste, detentor de 98% de todo camarão produzido no país, contudo, o Brasil sofreu no ano de 2003 à acusação de dumping dos EUA. Para estudar esses efeitos foi utilizada a teoria de Campos e Vito (2004) sobre impactos econômicos sob produtos acusados de dumping. Com base nessa teoria, foram elaborados quatro cenários que tem como objetivo, determinar possíveis perdas aos criadores de camarão do Brasil. Com isso, foram determinados os possíveis danos em cada fase da acusação de dumping, seus impactos econômicos bem como na geração de emprego conforme Costa e Sampaio (2004). Para isso, foram coletado dados do MDIC, referentes as exportações de camarão do Brasil entre os anos de 1996 a 2004, projetando seu comportamento e tendência para os próximos anos. Dessa forma o estudo observou impactos negativos a acusação de dumping na carcinicultura, nas suas diversas fases do julgamento

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Le travail de thèse porte sur l’étude du comportement mécanique d’un tissu soumis à un impact balistique en utilisant une modélisation multi-échelle prenant en compte les fibres et les fils. Cette approche micro-méso permet de mettre en évidence les phénomènes physiques pouvant se produire lors d’un impact balistique sur un tissu. A l’échelle du fil, une étude paramétrique a permis de cerner l’influence des propriétés physiques et mécaniques sur les réponses balistiques d’un tissu 2D. En plus, les effets de la localisation de l’impact sont étudiés pour tenir compte de la position du projectile sur un tissu 3D. A l’échelle de la fibre, une analyse fine des déformations en compression transversale d’un fil est développée. Ces phénomènes sont pris en considération pour prédire la tenue balistique d’un fil soumis à un impact transversal en utilisant une modélisation à l'échelle microscopique (échelle d'une fibre). Aussi, un tissu est modélisé en utilisant une approche multi-échelle. En effet, la zone affectée par l’impact est modélisée à une échelle microscopique tandis que les autres zones sont modélisées à une échelle mésoscopique. Une analyse des résultats est effectuée en termes d'évolutions des vitesses d'impact avec et sans perforation, des énergies cinétique et déformation et des forces d'impact. Les résultats numériques sont validés par confrontation aux données expérimentales. / The thesis focuses on the study of mechanical behavior of a fabric subjected to ballistic impact by using a multi-scale modeling that takes into account fibers and yarns. This micro-meso approach allows highlighting the physical phenomena that may occur during the ballistic impact on fabric. At the yarn level, a parametric study enables investigation into the influences of physical and mechanical yarn properties on the ballistic behavior of a plan-woven-fabric. Also, the effects of the impact localization are investigated to take into account the strike position of the projectile on a 3D fabric. At the fibers level, a detailed analysis of transverse compressive deformation of yarn is developed. These phenomena are considered to predict the ballistic response of a yarn subjected to a transverse impact using modeling at the microscopic scale (the scale of fiber). A modeling of fabric using a multi-scale approach is also performed. In this model, the area affected by the impact is modeled on the microscopic scale, while other areas are modeled on the mesoscopic scale. An analysis of the results is carried out regarding projectile velocity history, the kinetic energies and deformation, and impact forces in the cases of impact with and without perforation. The numerical results are validated by comparison with experimental data.

3 pp. / Estimates economic impacts of Cooperative Extension's involvement in collaborative rangeland management efforts with a rancher and federal agencies for a Northern Arizona grazing allotment.

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