Accelerated Test Life
Mostrando 13-22 de 22 artigos, teses e dissertações.
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13. Efeitos da reposiÃÃo nutricional sobre o crescimento somÃtico e Ãsseo de ratos desnutridos precocemente
Were assessed the effects of a normoproteic diet replacement of imposed during of accelerated bone growth on somatic growth, the epiphyseal plate and bone growth in young rats malnourished from the of lactation period. Were used male Wistar rats randomly distributed in groups: Nourished Group (NG, n = 10; breastfed pups by mothers that received normoproteic
Publicado em: 2009
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14. Contribuição ao estudo da carbonatação do concreto com adição de sílica ativa em ambiente natural e acelerado
Devido à preocupação com a durabilidade das estruturas de concreto armado surgiram novas linhas de pesquisa destacando-se, dentre elas, a previsão de vida útil. Estes estudos deram origem a diversos modelos que tentam estabelecer o comportamento do concreto quando exposto a ambientes agressivos durante um determinado período. Existem várias maneiras d
Publicado em: 2007
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15. Uso de métodos bayesianos em testes de vida acelerados no controle da qualidade de produtos industriais.
In this work, we introduce a Bayesian approach for quality control of industrial products, assuming units in test under stress levels higher than the usual level. We assume dierent distributions for the lifetimes of the units under a type II censoring mechanism and a general stress-response model that includes the usual accelerated life test models. Using a
Publicado em: 2006
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16. Parâmetros topográficos para avaliação, caracterização e controle tribológicos de superfícies de engenharia / Topographic parameters for evaluation, characterization and control of engineering surfaces
The topographic characterization of engineering surfaces is very important in applications involving friction, wear and lubrication. This practice started in the 1930s and until now great efforts have been put to developing new methods for engineering surfaces. Although most of the surfaces are specified using 2D (two dimensions) parameters as Ra (average ro
Publicado em: 2006
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17. O efeito de reparametrização em testes de sobrevivência acelerados
Accelerated life tests are frequently used in industrial experiments to obtain measures on the reliability of products. In these tests, the units are submited at higher levels of stress than usual and the informations obtained are utilized to inference on the reliability of the product, under normal operating conditions. A practical problem, refers to the ac
Publicado em: 2003
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18. Melhor dose e dose econômica de TBHQ nos óleos de milho e canola. / Best and economical doses of tbhq in corn and canola oils.
The increasing utilization of PET packaging in the last years in Brazil has concerned oil producers regarding oxidation. In this work, corn and canola oils, free from antioxidants and citric acid, were added of different TBHQ concentrations, and submited to accelerated (thermo and light induced) oxidation in a Schaal oven test at 63 0 C for 120 hours and in
Publicado em: 2003
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19. Estudo da substituição de TiO2 por Ta2O5 em eletrodos binários de óxido de rutênio: preparação, caracterização eletroquímica e investigação estrutural e morfológica. / Study of the substitution of TiO2 for Ta2O5 in binary oxide ruthenium electrodes: preparation, electrochemical characterization and structural and morphologic investigation.
Neste trabalho estudou-se a influência da substituição de TiO2 por Ta2O5 nas propriedades estruturais e eletrocatalíticas do sistema RuO2/Ta2O5. Uma investigação sistemática das propriedades estruturais, morfológicas, eletroquímicas e eletrocatalíticas para a produção de O2 em meio ácido foi conduzida usando ânodos de composição nominal Ti/(x
Publicado em: 2002
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20. Social structuring of mammalian populations and rate of chromosomal evolution.
To test the hypothesis that the evolution of organisms is dependent to a large degree on gene rearrangement, we devised a way of estimating rates of evolutionary change in karyotype. This non-biochemical method is based on consideration of chromosomal variability within taxonomic groups having a fossil record. The results show that chromosomal evolution has
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21. Protein synthetic errors do not increase during aging of cultured human fibroblasts.
To test the error catastrophe theory of aging we determined the error frequency of protein synthesis in several strains of cultured human fibroblasts at early and late passage. Error rates were calculated from analysis of native and substituted actins on two-dimensional gels of cellular proteins after induction of mistranslation by histidine starvation in th
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22. A joint hazard and time scaling model to compare survival curves.
To provide a more general method for comparing survival experience, we propose a model that independently scales both hazard and time dimensions. To test the curve shape similarity of two time-dependent hazards, h1(t) and h2(t), we apply the proposed hazard relationship, h12(tKt)/ h1(t) = Kh, to h1. This relationship doubly scales h1 by the constant hazard a