Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-10T21:25:15Z No. of bitstreams: 1 JoaoRonybertoCavalcanteRibeiro_DISSERT.pdf: 10659688 bytes, checksum: 7ec8ae4a93f2bbc61768b6aa5b4d8027 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-17T21:43:40Z (GMT) No. of bitstreams: 1 JoaoRonybertoCavalcanteRibeiro_DISSERT.pdf: 10659688 bytes, checksum: 7ec8ae4a93f2bbc61768b6aa5b4d8027 (MD5) / Made available in DSpace on 2016-03-17T21:43:41Z (GMT). No. of bitstreams: 1 JoaoRonybertoCavalcanteRibeiro_DISSERT.pdf: 10659688 bytes, checksum: 7ec8ae4a93f2bbc61768b6aa5b4d8027 (MD5) Previous issue date: 2015-02-27 / O litoral do Estado do Rio Grande do Norte ? caracterizada pela presen?a de dunas e fal?sias. Estas ?ltimas consistem em taludes com altura de at? 40 metros e inclina??o variando de 30o a 90o com a horizontal. Assim, esta disserta??o teve como objetivo a avalia??o da estabilidade da fal?sia da Ponta do Pirambu em Tibau do Sul/RN, e a realiza??o de um estudo param?trico sobre a estabilidade de uma fal?sia homog?nea considerando como vari?veis a coes?o do material, a altura da fal?sia e a inclina??o do talude. O estudo na Ponta do Pirambu considerou ainda a possibilidade da exist?ncia de uma cobertura coluvionar com espessura variando de 0,50 a 5,00 metros. As an?lises foram realizadas pelo m?todo de Bishop, utilizando o programa GEO5. Na an?lise param?trica foram produzidos gr?ficos que relacionam altura da fal?sia com a inclina??o, para fatores de seguran?a iguais a 1,00 e 1,50; al?m de gr?ficos onde ? poss?vel obter facilmente o menor fator de seguran?a a partir da coes?o, altura da fal?sia e sua inclina??o. Concluiu-se que esses gr?ficos s?o muito ?teis para an?lises preliminares, para a defini??o de ?reas cr?ticas em mapeamentos de riscos em ?reas de fal?sias e para determina??o de uma equa??o para obten??o do menor fator de seguran?a em fun??o dos par?metros de resist?ncia e da geometria de um talude. Em rela??o ? fal?sia da Ponta do Pirambu, os resultados mostraram que a fal?sia est? sujeita a deslizamentos superficiais localizados nos pontos onde pode haver a presen?a do col?vio com espessuras superiores a dois metros. Entretanto, a fal?sia se mant?m est?vel, apresentando fator de seguran?a global igual ou superior a 2,50 na condi??o saturada. / The coastline from Rio Grande do Norte state is characterized for the presence of dunes and cliffs. The latter consist of slopes with height up to 40 meters and inclinations ranging from 30? to 90? wich horizontal. Thus, this dissertation had as objective the evaluation of the stability of cliff from Ponta do Pirambu in Tibau do Sul/RN, and the realization of a parametric study on the stability of a homogeneous cliff considering as variables the material's cohesion, the cliff height and the slope inclination. The study in Ponta do Pirambu considered yet the possibility of the existence of a colluvial cover with thickness ranging from 0.50 to 5.00 meters. The analyzes were performed by Bishop method, using GEO5 software. In parametric analysis were produced graphics that relate height cliff with the inclination, to safety factors equals to 1.00 and 1.50; besides graphics where it is possible easily get the lowest safety factor as from the cohesion, cliff height and its inclination. It was concluded that these graphs are very useful to preliminary analyzes, for the definition of critical areas in risk mappings in areas of cliffs and for determination of an equation for obtaining the lowest safety factor function of the strength parameters and of slope geometry. Regarding the cliff from Ponta do Pirambu, the results showed that the cliff is subject to superficial landslides located in the points where may there be the presence of colluvium with thicknesses greater than two meters. However, the cliff remains stable presenting the global safety factor equal or superior to 2.50 in the saturated condition.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-22T21:41:53Z No. of bitstreams: 1 JoseIdifranseAguiarTrindade_TESE.pdf: 3433912 bytes, checksum: cc18488777701871fa15bf7410b660d3 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-22T22:05:27Z (GMT) No. of bitstreams: 1 JoseIdifranseAguiarTrindade_TESE.pdf: 3433912 bytes, checksum: cc18488777701871fa15bf7410b660d3 (MD5) / Made available in DSpace on 2016-04-22T22:05:27Z (GMT). No. of bitstreams: 1 JoseIdifranseAguiarTrindade_TESE.pdf: 3433912 bytes, checksum: cc18488777701871fa15bf7410b660d3 (MD5) Previous issue date: 2015-01-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Este trabalho tem como objetivo investigar o comportamento de elementos fractais e elementos helicoidais em estruturas planares de microfita. Em particular, as superf?cies seletivas de frequ?ncia (FSS) tiveram seus elementos convencionais alterados para formatos fractais e para o formato helicoidal. O substrato diel?trico usado ? de fibra de vidro (FR-4) e tem espessura de 1,5 mm, permissividade el?trica relativa de 4,4 e tangente de perdas igual a 0,02. Para as FSS, adotou-se a geometria fractal pentagonal de D?rer e a geometria helicoidal. Para efetuar as medi??es, foram utilizadas duas antenas cornetas em visada direta, conectadas por cabo coaxial a um analisador de redes vetorial. Alguns prot?tipos foram selecionados para fabrica??o e medi??o. A partir dos resultados preliminares obtidos, objetivou-se encontrar aplica??es pr?ticas para as estruturas a partir do cascateamento entre elas. Para as FSSs com elementos fractais de D?rer, observou-se um comportamento multibanda proporcionado pela geometria fractal, ao mesmo tempo em que a largura de banda se tornou estreita na medida em que o n?vel de itera??o fractal aumentou, tornando-a uma estrutura mais seletiva em frequ?ncia, com um maior fator de qualidade. Uma an?lise param?trica possibilitou a an?lise da influ?ncia da varia??o da camada de ar entre elas. As estruturas fractais pentagonais foram consideradas e cascateadas. O cascateamento entre determinadas estruturas pentagonais apresentou um comportamento tri-band para determinados valores da camada de ar entre elas, com aplica??es na banda licenciada 2,5 GHz (2,3 ~ 2,7 GHz), e 3,5 GHz (3,3 ~ 3,8 GHz). Para as FSSs com elementos helicoidais, seis estruturas foram consideradas. A partir de resultados preliminares obtidos com a an?lise isolada das estruturas, o cascateamento entre elas proporcionou o aumento da largura de banda, na medida em que a espessura da camada de ar aumenta. Com a finalidade de encontrar aplica??es pr?ticas para as estruturas helicoidais cascateadas, as estruturas propostas foram cascateadas e as mesmas encontraram aplica??es na banda-X (8,0 ~ 12,0 GHz), e na banda n?o licenciada que compreende a faixa de 5,25 a 5,85 GHz. Na caracteriza??o num?rica e experimental das estruturas abordadas, utilizou-se, respectivamente, o software comercial Ansoft Designere um analisador de redes vetorial, modelo N5230A da Agilent. / This work aims to investigate the behavior of fractal and helical elements structures in planar microstrip. In particular, the frequency selective surfaces (FSSs) had changed its conventional elements to fractal and helical formats. The dielectric substrate used was fiberglass (FR-4) and has a thickness of 1.5 mm, a relative permittivity 4.4 and tangent loss equal to 0.02. For FSSs, was adopting the D?rer?s fractal geometry and helical geometry. To make the measurements, we used two antennas horns in direct line of sight, connected by coaxial cable to the vector network analyzer. Some prototypes were select for built and measured. From preliminary results, it was aimed to find practical applications for structures from the cascading between them. For FSSs with D?rer?s fractal elements was observed behavior provided by the multiband fractal geometry, while the bandwidth has become narrow as the level of iteration fractal increased, making it a more selective frequency with a higher quality factor. A parametric analysis allowed the analysis of the variation of the air layer between them. The cascading between fractal elements structure were considered, presented a tri-band behavior for certain values of the layer of air between them, and find applications in the licensed 2.5GHz band (2.3-2.7) and 3.5GHz band (3.3-3.8). For FSSs with helical elements, six structures were considered, namely H0, H1, H2, H3, H4 and H5. The electromagnetic behavior of them was analyzed separately and cascaded. From preliminary results obtained from the separate analysis of structures, including the cascade, the higher the bandwidth, in that the thickness of the air layer increases. In order to find practical applications for helical structures cascaded, the helical elements structure has been cascaded find applications in the X-band (8.0-12.0) and unlicensed band (5.25-5.85). For numerical and experimental characterization of the structures discussed was used, respectively, the commercial software Ansoft Designer and a vector network analyzer, Agilent N5230A model.