971 resultados para Zona de cisalhamento


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Fracture surfaces are the fracture process marks, taht it is characterized by energy release guieded by failure mode. The fracture toughness express this energy em stress and strain terms in pre-cracked samples. The strectch zone is the characteristic region forms by the transition of fatigue fracture and final fracture and it width demonstrate the relation with failure energy release.The quantitative fractography is a broadly tool uses in failure surfaces characterization that it can point to a material’s aspect or a fracture process. The image processing works like an investigation tool, guinding a lot of studies in this area. In order to evaluate the characterization effectivity and it respectivity studies, it used 300M steel that it was thermal treated by an aeronautical process known and it characterized by tensile test and energy dispersive spectroscopy (EDS). The tensile test of this material, made by ASTM E8, allowed the head treatment effectivity confirmation, beyond of mechanics porperties determination. The EDS confirmed the material composition, beyond of base the discussion about fracture mechanism presence. The fracture toughness test has also made, that it works to obtain the fracture surfeaces studies below self-similarity and self-affinity approaches. In front of all the exposed it was possible to conclude that the fractal dimension works like a study parameter of fracture process, allowinf the relation of their values with changes in thickness, which interferes directly in material’s behaviour in fracture toughness approach

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A Zona de Falha de Cássia constitui um feixe de falhas de direção preferencial NW-SE e aproximadamente 2 km de largura. Dados de campo, petrográficos e microestruturais evidenciam uma longa história deformacional da zona de falha. Assim, foram caracterizadas três fases de atividade/movimentação da Zona de Falha de Cássia. A primeira fase (précambriana) é caracterizada por deformação em regime dúctil, acarretando na geração de milonitos formados em condições metamórficas de fácies xisto verde. Este é o estágio de formação da falha, apresentando caráter transcorrente oblíqua, com movimentação sinistral inversa. A segunda fase corresponde a uma reativação da zona de falha como uma falha normal, com bloco alto a NE e bloco baixo a SW da referida estrutura. Seu registro é dado pela ocorrência localizada de brechas e cataclasitos. Este episódio de deformação eminentemente rúptil é correlacionado com o Soerguimento do Alto Paranaíba, o que indica movimentação da falha no Neocretáceo. A terceira e última fase é marcada pela formação de depósitos sedimentares plio-pleistocênicos compostos por brecha sedimentar de leques aluviais e sedimentos argilosos lacustres. Tais depósitos são interpretados como originados pelo represamento da drenagem subatual e conseqüente mudança do nível de base local, em decorrência de uma reativação da Zona de Falha de Cássia. O referido pacote sedimentar apresenta-se localmente cortado por fraturas, zonas brechadas e falhas, caracterizando atividade neotectônica na região. Além disso, foi mostrada a forte influência da zona de falha no desenvolvimento da paisagem da região, sendo constatada a inversão do relevo e da drenagem na área estudada.

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O presente estudo teve como objetivos principais analisar a biodiversidade de macroinvertebrados bentônicos em diferentes pontos localizados no fundo da Lagoa do Mian, zona de desembocadura do rio Paranapanema, na Represa de Jurumirim, Estado de São Paulo. Nove pontos de amostragem ao longo da lagoa foram selecionados, distribuídos em três transectos. Cada transecto possuía um ponto na margem direita, um ponto na margem esquerda e um ponto no meio. As coletas foram realizadas em dois períodos do ano, um em março e outro em agosto, para fins de comparação. 2009 representou um ano atípico com relação aos níveis pluviométricos, ocorrendo chuvas intensas no período de julho (um mês tipicamente seco). Foram medidas as variáveis físico-químicas da água, tais como: transparência, profundidade, oxigênio dissolvido, pH, condutividade elétrica e temperatura. Foram recolhidas amostras do sedimento para análise da fauna bentônica e análise do sedimento (quantidade de matéria orgânica presente e granulometria) utilizando-se a draga de Petersen. O material foi triado sob microscópio estereoscópico. A seguir, foi feita a identificação e contagem dos indivíduos. Medidas de densidade, abundância relativa, riqueza, diversidade e equitabilidade foram calculadas. A análise mostrou maior abundância dos táxons no mês de agosto, apontando para a predominância de alguns grupos, como Chaoboridae, Nematoda, Oligochaeta e Chironomidae, este último apenas no segundo mês de coleta. A distribuição dos organismos foi mais significativamente influenciada pela a condutividade elétrica da água, pela transparência, pelo oxigênio dissolvido e por características do sedimento

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The study area is includes in the geological context of Arenópolis Magmatic Arc, a region where there are neoproterozoic associations of granodioritic and tonalitic composiotion. (Ortogneisses of the western Goiás) and sequences metavolcanic-sedimentary (Jaupaci Metavolcanic-sedimentary Sequence ). In the mapped area, both units are covered by a cover-laterite. The Ortogneisses from Goiás West consist of a source granodioritic gneisses, corresponding to the Biotite granodiorite gneisse, and also by tonalitic gneiss composition corresponding to Metatonalit. The Jaupaci Metavolcanic-sedimentary Sequence is formed by Chlorite Schist (Metabasalt), Biotite Schist (Metadacite) and Sericite Schist (Metarhyolite), and even intrusions Sin/Tardi e Post Tectonic, granite to diorite composition (Diorites), and alson tonalitic (Bacilandia Tonalite). Post tectonic intrusions are observed, wich were Hornblend Diorite Porphyry and Lamprophyres, Structural analysis allowed the identification of three deformational events, Dn-1, Dn and Post-Dn. The first event is associated with a bygone foliation, lineation which generates an intersectional event, generating the foliation Sn, this being the most important structure in the study area, generating even the type mineral lineation and stretch. The last deformational event is characterized by folds on different scales, affecting the Sn foliation. The rocks of the region have features s active hydrothermal and regional metamorphism, and are composed os assembly indicative of mineralogical facies metamorphism Green Schist, in chlotite zone, with evidence of retro metamorphism. Locally there are sulfides as pyrite, arsenopyrit and pyrhotite, and te mineralization is associated with the arsenopyrite

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Although the regular practice of physical exercise for the maintenance of the nutritional state and quality of life is important, it is not a common habit among the elderly, especially those of the lower income social bracket. The objective was to characterize and compare according to social-economic conditions and anthropometric indexes of the nutritional state of the elderly who regularly practice and those who do not practice exercises, offered at no cost, in the Northern zone of São José do Rio Preto-SP. In this study, 110 elderly women participated, of which 60 (group P) exercised regularly and 50 did not (group NP). Group P participated in a special gym program, free of charge, for at least 2 years, 2 to 3 times a week, one hour a day. Group NP was recruited from the same location as Group P. The comparison between the groups of elderly women was proportionately distributed according to marital status, level of education, means of locomotion, results of body mass index (IMC), waist to hip ratio (RCQ) and calf circumference, using the chi-square test. Comparisons were also made of average age, per capita family income, individual income, IMC, arm and triceps skin fold measured by t-Test. Differences were not found in all the comparisons made. The variables that stood out were the IMC (overweight) and RCQ (risk of chronic diseases) results, which were above what was expected, and the high frequency of walking and riding buses for both groups of elderly women (about 60%). We came to the conclusion that the low-intensity exercise program evaluated made no difference in the nutritional profile of the elderly who also used walking as a means of getting around.

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Because the high consumption of welded pipe for exploration and conduction oil and gas, optimization of manufacturing processes is necessary to obtain better productivity, efficiency and cost reduction. The objective of this study is to analyze the forms of heat transfer during the welding of pipes using longitudinal submerged arc process them to propose a model for the temperature distribution in the welded region. For this analysis are addressed as the heat transfer modes operate in the specified welding process and the necessary considerations for the mathematical model were obtained. The calculations were performed and the simulations needed to obtain the temperature distribution in the tube were carried out. Therefore, the practice was satisfactory and the results showed a range of temperatures along the pipe for a particular model and the future suggestions for improvement of this work

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Observa-se como estratégia mundial para a conservação da biodiversidade a criação de unidades de conservação. No Brasil, especificamente no Estado de São Paulo, devido a intensa degradação da Mata Atlântica, verifica-se a criação de unidades de proteção integral, a fim de se preservar de modo restrito os recursos naturais que ainda lhe restam. Na cidade de Ribeirão Preto, uma região com alto desempenho agrícola e intensa expansão urbana, constata-se a presença de uma Estação Ecológica (EERP), fragmento florestal de 154,16 ha, altamente isolado e fragmentado. Assim, a EERP e sua zona de amortecimento (ZA) vêm sendo fortemente pressionada pela expansão urbana e agrícola da região, comprometendo a sua integridade ecossistêmica. Dentre os impactos negativos gerados destacam-se: alta especulação imobiliária e o intenso cultivo de monoculturas, que contribuem para a degradação do solo nas regiões do entorno. A fim de se reduzir tais impactos, o presente trabalho buscou apresentar um prognóstico de planejamento ambiental para a ZA da EERP, a qual se encontra altamente impactada, segundo os critérios definidos por Ranieri (2004). Desse modo, criou-se cenários ideais para a preservação dos recursos naturais do local

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Pós-graduação em Geociências e Meio Ambiente - IGCE

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This study evaluated in vitro the shear bond strength of brackets bonded with xenon plasma arc light, light-emitting diode (LED) and conventional halogen light using different curing times. Brackets were bonded to the buccal surface of 60 human maxillary premolars allocated to five groups. In groups 1 and 2, the resin was cured with the plasma arc for three and six seconds (s), respectively; in groups 3 and 4, the LED was used for five and ten s, respectively; and in group 5, the halogen light was used for 40 s. The specimens were stored in water for 24 hours and subjected to a shear force until bracket failure. The debonding pattern was classified according to the adhesive remnant index (ARI). The results were assessed by Anova and the SNK post-hoc test. No differences were detected among groups 2, 4 and 5, which showed higher averages than groups 1 and 3, which were not different between themselves. The ARI scores showed no differences among the three types of light sources in all times tested. Plasma arc and LED lights can be used with shorter curing times, within certain limits, than conventional halogen light for bonding orthodontic brackets, without decreasing bond strength.

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Introduction: the oral rehabilitation in edentulous patients using removable complete dentures is a classic treatment, easily accessible, and presenting satisfactory results. However, to succeed in this type of treatment, stability is an extremely important factor. The neutral zone technique for the production of complete dentures determines the oral cavity space for the positioning of teeth and denture base that provide a neutralization of the forces delivered by lips, cheeks, and tongue, providing better stability and retention of prostheses, which is indicated in cases with history of difficulties in adapting the conventional mandibular denture. Objective and case report: this paper aimed to describe a clinical case report of the oral rehabilitation of a patient with paraprosthetic muscles hypertonicity through removable complete dentures produced by the neutral zone technique, using condensation silicone. Final considerations: the use of condensation silicone for the development of the neutral zone technique showed to be a good alternative for the development of this clinical case, providing satisfactory stability and retention of the complete mandibular denture.

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Objective and Case report: The purpose of this paper is to describe the neutral zone technique in a patient with oral deformity on the right labial commissure due to the resection of an oral cancer, enhancing the difficulty resulting from mouth limited opening and the use of tissue conditioner material to determine the neutral zone. Complete denture was obtained through this technique, providing good retention and stability which made functional rehabilitation feasible to patient of his or her masticatory function. Final considerations: The neutral zone technique in complete dentures will determine a specific intraoral area for tooth position and denture base contour where the forces generated by lips, cheeks and tongue are neutralized. The objective of this technique is to provide an alternative approach for patients who presented an historic instability of lower complete denture: atrophic ridge, oral deformities and also with disorder problems. An oral rehabilitation using this technique improves comfort to the patient providing retention and stability of mandibular complete dentures.