Changes of microstructure in alpha AgZn during post-deformation annealing after cold-rolling

The annealing processes of deformation-induced defects after cold-rolling to about 30 and 60% thickness reduction were investigated for Ag-21, 23, 28 at% Zn by means of residual electrical resistivity, microhardness, light microscopy and transmission electron microscopy (TEM) Three annealing stages have been detected and consistently interpreted as annealing-out of mainly point defects and their agglomerates (stage I), formation of dislocation cells and recrystallized strain-free grains (stage II) and grain growth (stage III). Further, it is tried to determine the evolution of defect production (point defects and dislocations) during rolling deformation from measured changes of electrical resistivity and microhardness. Copyright (C) 1996 Acta Metallurgica Inc.

Mechanical damping of the snoek peak in tantalum - Oxygen system

Interstitial solutes in body-centered cubic metals, such as oxygen in tantalum, produce ideally Snoek effects when they are in solutions enough diluted. However, for higher concentration of these solutes, more complex relaxation process can occur, as interaction between interstitial solutes and dislocations. Anelastic relaxation measurements were carried out in polycrystalline tantalum samples, using torsion pendulum inverted, operating between 300 K and 680 K and oscillation frequencies in the hertz bandwidth, for three different experimental sample conditions: as received sample, annealed and annealed followed by a treatment in an oxygen atmosphere. These measurements have revealed the following behavior: the intensity of the internal friction peak associated to matrix-interstitial interaction Ta-O decreased between the first run and the next runs, and this phenomenon did not occur for the others conditions. The variation of relaxation strength of Ta-O peak, with number of runs is due to a decrease of an amount of oxygen in solid solution, which can be associated with the precipitation of new phases in Ta sample and with the trapping of oxygen atoms by dislocations.

Mandible protrusion and decrease of TMJ sounds: An electrovibratographic examination

This study quantified by, electrovibratography, the amount of mandible protrusion required to decrease significantly temporomandibular joint (TMJ) vibratory energy as an aid in the diagnosis of the recapture of anteriorly displaced disk. Eighteen patients diagnosed as having anterior disk displacement with reduction and TMJ clicking were submitted to electrovibratographic examination at the first appointment and treated with a stabilizing appliance and anterior positioning appliance with 1 to 5 mm protrusion. Vibratory energy was checked in each of these positions. Baseline data were used as control. At the first appointment, the patients had vibrations with more elevated intensities at the middle and late phases of the mouth opening cycle. At only one clinical step, mandible protrusion was obtained with the anterior repositioning appliance, ranging from 1 to 5 mm protusion. At each new position, a new electrovibratographic exam was made. After the 5-mm mandibular projection, only 2 patients presented vibration, with means between 0.6 and 2.8 Hz. Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). The outcomes of this study indicate that 3 mm is the minimum amount of mandible protrusion to significantly decrease the TMJ vibratory energy and to recapture the displaced articular disk.

Estudo de propriedades anelásticas de MgB2

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fatores determinantes do deslocamento de setores intensivos em mão de obra para o Nordeste: o caso das grandes empresas calçadistas brasileiras a partir dos anos 1990

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do tratamento térmico de alívio de tensões assoaciado à elevada energia de soldagem na tenacidade da zona termicamente afetada de um aço TMCP microligado aplicado em estruturas off-shore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Afastamento por licença-saúde, readaptação funcional e suas implicações no gerenciamento de enfermagem

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

Análise de parâmetros adimensionais num escoamento em meio poroso visando a deformação de elementos cerâmicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Colonoscopia virtual em cães

Pós-graduação em Medicina Veterinária - FMVZ

Efeito do oxigênio intersticial no módulo de elasticidade de Ligas Ti-15Mo-xZr(x=5,10,15%p)

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

Estudo da fadiga em liga de alumínio aeronáutico 7475-T761

This work will address the study of fatigue conditions with constant load in an alloy of aluminum analysis 7475 - T761, so we can better understand the conditions of the aircrafts which contain this alloy in their structures. A literature review, which was discussed the concepts of fracture mechanics, fatigue, aeronautical components, chemical analysis of aluminum alloys, fatigue problems that appears in the aircrafts, metallographic analysis, and testing of optical microscopy tensile, fatigue and microhardness, surface analysis (MEV) study of the chemical composition of the alloy in question, the main causes of crashes, was performed, completing the work, analysis of data from tensile test, hardness and fatigue together with the interpretation of images of optical microscopy and scanning electron was taken. The data indicated the high mechanical strength of the alloy, along with its microstructure indicating elongated grains and high surface contour, which shows such resistance by hindering the movement of dislocations. The grooves are clearly shown in the MEV images as well as the classic with increased fatigue loading and subsequent reduction of the number of cycles to rupture behavior shown in the graphs. Therefore we observed the optimal behavior is supported by the league when subjected to fatigue loadings

Interaction between recrystallization and strain-induced precipitation in a high Nb- and N-bearing austenitic stainless steel: influence of the interpass time

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O ensino religioso na escola pública: regras que cooperam para sua organização

Pós-graduação em Educação - FCT

Características e fatores associados às quedas atendidas em serviços de emergência

OBJETIVO: Analisar as características dos atendimentos decorrentes de quedas em serviços de urgência e emergência e identificar fatores associados. MÉTODOS: Estudo transversal com 12.617 atendimentos decorrentes de quedas registrados no Sistema de Vigilância de Violências e Acidentes, coletados em 23 capitais e Distrito Federal, de setembro a novembro de 2009, por meio de uma amostra por conglomerado. Foi utilizada a técnica de análise de correspondência, por permitir a observação conjunta de um grande número de variáveis qualitativas. RESULTADOS: A maior parte das vítimas foi do sexo masculino (56,5%), faixa etária de 0 a 19 anos (45,7%) e declarados não brancos (62,2%). A maioria das quedas ocorreu na residência (54,6%) e via pública (17,4%); 14,3% foram relacionadas ao trabalho. Os tipos predominantes foram "queda no mesmo nível" (57,0%) e "queda de escada/degrau" (15,6%). A maioria das lesões foi classificada como entorse, luxação, contusão, corte e laceração (68,3%). Quedas dentre as crianças associaram-se à ocorrência na residência; com os adolescentes na escola; e jovens na prática esportiva. Quedas em adultos estiveram associadas ao local de trabalho, queda de andaimes, telhados, escada/degrau e buracos e uso de álcool. As quedas no mesmo nível resultaram em lesões de menor gravidade, em membros inferiores e superiores, e as quedas de andaime e telhado se associaram com lesões de maior gravidade e internações. CONCLUSÕES: Os resultados mostram que estratégias para a prevenção das quedas devem ser implantadas particularmente em residências, escolas e ambientes de trabalho.