Hygrothermal effects on the shear properties of carbon fiber/epoxy composites

The environmental factors, such as humidity and temperature, can limit the applications of composites by deteriorating the mechanical properties over a period of time. Environmental factors play an important role during the manufacture step and during composite's life cycle. The degradation of composites due to environmental effects is mainly caused by chemical and/or physical damages in the polymer matrix, loss of adhesion at the fiber/matrix interface, and/or reduction of fiber strength and stiffness. Composite's degradation can be measure by shear tests because shear failure is a matrix dominated property. In this work, the influence of moisture in shear properties of carbon fiber/epoxy composites ( laminates [0/0](s) and [0/90](s)) have been investigated. The interlaminar shear strength (ILSS) was measured by using the short beam shear test, and Iosipescu shear strength and modulus (G(12)) have been determinated by using the Iosipescu test. Results for laminates [0/0](s) and [0/90](s), after hygrothermal conditioning, exhibited a reduction of 21% and 18% on the interlaminar shear strenght, respectively, when compared to the unconditioned samples. Shear modulus follows the same trend. A reduction of 14.1 and 17.6% was found for [0/0](s) and [0/90](s), respectively, when compared to the unconditioned samples. Microstructural observations of the fracture surfaces by optical and scanning electron microscopies showed typical damage mechanisms for laminates [0/0](s) and [0/90](s).

Effects of surface treatments on the fatigue strength of AISI 4340 aeronautical steel

Internal residual stresses significantly influence the fatigue strength of coated materials. It is well known that chromium plating is the most used electrodeposited coating for important industrial applications. However, pressure to identify alternatives or to improve the chromium electroplating process have increased in recent years, related to the reduction in fatigue strength of the base material and to environmental requirements. The high efficiency and fluoride free hard chromium electroplating there called accelerated) is an improvement to the conventional process. One environmentally safer and cleaner alternative to hard chromium plating is tungsten carbide thermal spray coating applied by the High Velocity Oxy-Fuel (HVOF) process. To increase the fatigue strength of chromium plated materials, coating thickness and microcracks density are important parameters to be controlled. Techniques as compressive residual stresses induced by shot peening and multilayers, are also used. The aim of this study was to analyse the effects on AISI 4340 steel, in the rotating bending fatigue behaviour, of the: tungsten carbide thermal spray coating applied by HP/HVOF process; chemical nickel underplate, and shot peening process applied before coating deposition, in comparison to hard chromium electroplatings. Rotating bending fatigue test results indicate better performance for the conventional hard chromium plating in relation to the accelerated hard chromium electroplating. Tungsten carbide thermal spray coating and accelerated hard chromium plate over nickel resulted in higher fatigue strength when compared to samples conventional or accelerated hard chromium plated. Shot peening showed to be an excellent alternative to increase fatigue strength of AISI 4340 steel hard chromium electroplated. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Beam Search Algorithms for Minimizing Tool Switches on a Flexible Manufacturing System

In the minimization of tool switches problem we seek a sequence to process a set of jobs so that the number of tool switches required is minimized. In this work different variations of a heuristic based on partial ordered job sequences are implemented and evaluated. All variations adopt a depth first strategy of the enumeration tree. The computational test results indicate that good results can be obtained by a variation which keeps the best three branches at each node of the enumeration tree, and randomly choose, among all active nodes, the next node to branch when backtracking.

Validade e confiabilidade da versão informatizada do inventário Million de estilos de personalidade

Currently, several psychological and non-psychological tests can be found in publishes without standardization on procedures set in different psychological areas, like intelligence, emotional states, attitudes, social skills, vocation, preferences and others. The computerized psychological testing is a extension of traditional testing psychological practices. However, it has own psychometrics qualities, either by its matching in a computerized environment or by the extension that can be developed in it. The current research, developed from a necessity to study process of validity and reliability on a computerized test, drew a methodological structure to provide parallel applications in numerous kinds of operational groups, evaluating the influences of the time and approach in the computerization process. This validity refers to normative values groups, reproducibility in computerized applications process and data processing. Not every psychological test can be computerized. Therefore, our need to find a good test, with quality and plausible properties to transform in computerized application, leaded us to use The Millon Personality Inventory, created by Theodore Millon. This Inventory assesses personality according to 12 bipolarities distributed in 24 factors, distributed in categories motivational styles, cognitive targets and interpersonal relations. This instrument doesn t diagnose pathological features, but test normal and non adaptive aspects in human personality, comparing with Theodore Millon theory of personality. In oder to support this research in a Brazilian context in psychological testing, we discuss the theme, evaluating the advantages and disadvantages of such practices. Also we discuss the current forms in computerization of psychological testing and the main specific criteria in this psychometric specialized area of knowledge. The test was on-line, hosted in the site http://www.planetapsi.com, during the years of 2007 and 2008, which was available a questionnaire to describe social characteristics before test. A report was generated from the data entry of each user. An application of this test was conducted in a linear way through a national coverage in all Brazil regions, getting 1508 applications. Were organized nine groups, reaching 180 applications in test and retest subject, where three periods of time and three forms of retests for studies of on-line tests were separated. Parallel to this, we organized multi-application session offline group, 20 subjects who received tests by email. The subjects of this study were generally distributed by the five Brazilian regions, and were noticed about the test via the Internet. The performance application in traditional and on-line tested groups subsidies us to conclude that on-line application provides significantly consistency in all criteria for validity studied and justifies its use. The on-line test results were related not only among themselves but were similar to those data of tests done on pencil and paper (0,82). The retests results demonstrated correlation, between 0,92 and, 1 while multisessions had a good correlation in these comparisons. Moreover, were assessed the adequacy of operational criteria used, such as security, the performance of users, the environmental characteristics, the organization of the database, operational costs and limitations in this on-line inventory. In all these five items, there were excellent performances, concluding, also, that it s possible a self-applied psychometric test. The results of this work are a guide to question and establish of methodologies studies for computerization psychological testing software in the country

Transmission system expansion planning by an extended genetic algorithm

The paper presents an extended genetic algorithm for solving the optimal transmission network expansion planning problem. Two main improvements have been introduced in the genetic algorithm: (a) initial population obtained by conventional optimisation based methods; (b) mutation approach inspired in the simulated annealing technique, the proposed method is general in the sense that it does not assume any particular property of the problem being solved, such as linearity or convexity. Excellent performance is reported in the test results section of the paper for a difficult large-scale real-life problem: a substantial reduction in investment costs has been obtained with regard to previous solutions obtained via conventional optimisation methods and simulated annealing algorithms; statistical comparison procedures have been employed in benchmarking different versions of the genetic algorithm and simulated annealing methods.

Improved Fault Location on Distribution Feeders Based on Matching During-Fault Voltage Sags

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hydrogen embrittlement in an AISI 1045 steel component of the sugarcane industry

This paper will present a failure analysis of a chain component, manufactured with AISI 1045 steel and used for sugarcane transport. During the fabrication process, this component is submitted to induction hardening, just on one surface, before the galvanizing process. The occurrence of surface cracks, during storage, disables the usage of these components. Chemical and metallographic analyses, tensile, fracture toughness, and hardness tests, and fractography were conducted in order to determine the causes of failure. The steel chemical composition was in accordance with AISI 1045. The metallographic analyses and fractography did not exhibit the presence of zinc into the cracks; this is an indication that the cracks occurred after the galvanizing process. Tensile and fracture toughness test results are as expected. The crack surface and the fracture toughness specimen surfaces showed two different fracture micromechanisms: dimples and intergranular. The delayed fracture associated with the predominance of intergranular fracture micromechanism at the induction hardened layer and the high hardness level is a clear indication of the hydrogen embrittlement. (c) 2008 Elsevier Ltd. All rights reserved.

Uso de reguladores de crescimento no desenvolvimento e produção de crotalária

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

Exercise training attenuates acute hyperalgesia in streptozotocin-induced diabetic female rats

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

Perfil de habilidades de comunicação de dois irmãos com a Síndrome Alcoólica Fetal

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desempenho de escolares com dislexia do desenvolvimento em tarefas fonológicas e silábicas

OBJETIVO: caracterizar o desempenho em tarefas fonológicas e silábicas de escolares com dislexia do desenvolvimento e comparar estes achados com o desempenho de discentes com bom desempenho escolar. MÉTODOS: participaram do estudo 26 alunos de oito a 12 anos de idade, de ambos os sexos, de 2ª. a 4ª. séries do Ensino Fundamental municipal na cidade de Marilia-SP, divididas em GI: composto por 13 escolares com dislexia atendidos no Centro de Estudos da Educação e Saúde - CEES/UNESP e GII: composto por 13 alunos com bom desempenho acadêmico, pareados segundo sexo, idade e escolaridade com o GI. Como procedimento foi utilizada a Prova de Consciência Fonológica - Instrumento de Avaliação Seqüencial - CONFIAS. Os resultados foram analisados estatisticamente pelo Teste Mann-Whitney (comparação entre os grupos) e Teste dos Postos Sinalizados-Wilcoxon (comparação entre as variáveis). RESULTADOS: os resultados evidenciaram diferença estatisticamente significante, sugerindo melhor desempenho do GII em relação ao GI quanto às tarefas fonêmicas e silábicas. O GI apresentou diferença estatisticamente significativa nas tarefas silábicas e fonêmicas, com melhor desempenho nas primeiras. Entre os escolares do GII não houve grande diferença estatística entre tarefas silábicas, apenas entre tarefas fonêmicas. CONCLUSÃO: o estudo concluiu que escolares com dislexia do desenvolvimento apresentam dificuldades quanto à identificação de rima e produção de palavras com o som dado, apontando para um déficit em acessar os códigos e as representações fonológicas.

Tuberculose ativa em pacientes cirúrgicos com baciloscopia negativa no pré-operatório

OBJETIVO: Verificar a proporção de pacientes com baciloscopia negativa no pré-operatório e que apresentaram TB ativa na peça cirúrgica. MÉTODOS: Estudo retrospectivo de pacientes com diagnóstico histopatológico de TB ativa ou sequelar e operados entre os anos de 2003 e 2006 em um hospital universitário. Foram pesquisados antecedentes e aspectos clínicos relativos à doença, pesquisa de bacilos álcool-ácido resistentes (BAAR), tipo de cirurgia realizada e exame histopatológico da peça cirúrgica. RESULTADOS: Foram incluídos 43 pacientes, com média de idade de 44 ± 19 anos, sendo 27 do sexo masculino. Apresentavam história prévia de TB com tratamento adequado 28 pacientes, e 15 não referiam antecedentes para TB. O principal motivo da procura pelo serviço foi infecção de repetição, seguida por achados em exames de imagem. Dos 43 pacientes, foi pesquisado BAAR no pré-operatório em 35: 32 apresentaram resultados negativos e 3, resultados positivos. Dos 35 pacientes pesquisados, 26 apresentavam diagnóstico histopatológico de TB ativa e 9 de TB sequelar na peça cirúrgica; os outros 8 também foram diagnosticados com TB sequelar. A proporção de TB ativa em doentes com baciloscopia negativa foi de 72% (23/32), e o de baciloscopia negativa em TB ativa foi de 88% (23/26), sendo a pesquisa de BAAR positiva somente em 11,5% (3/26). CONCLUSÕES: A baciloscopia direta tem rendimento muito baixo, e muitos pacientes mesmo já tratados podem permanecer com TB em atividade com baciloscopia negativa. A TB ativa pode ser confundida com infecções secundárias ou com câncer.

Double muscle innervation using end-to-side neurorrhaphy in rats

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

Helicobacter pylori and EBV in gastric carcinomas: Methylation status and microsatellite instability

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

Análise da toxicidade no açude Riacho da Cachoeira, Lajes Pintadas (RN): um desafio interdisciplinar

Contamination by complex mixtures of various origins has been explored and studied for decades. Radon is a naturally occurring environmental contaminant that causes carcinogenic effects. These emissions can cause mutations in the lung tissue, which can initiate a carcinogenic process. Thus the dam Creek Falls, located in the municipality of Lajes Pintadas, was chosen for the development of this study, since cancer rates in the region reach 9% of the population annually, with this, the main objective of this study was evaluate the mutagenicity and toxicity of Riacho da Cachoeira damunder the influence of radon. The methodology ecotoxicological tests were performed with Ceriodaphinia dubia, as well as tests with Tradescantia pallida genotoxicologicos and Oreochromis niloticus. To understand how the population of Pintadas Slabs realizes the environment, we performed a study of environmental perception. The test results indicated that the reservoir water is toxic to test organimos exposed, found heavy metals, chloride, total and fecal coliforms as well as radon levels above the maximum allowed under Brazilian law. These results can be justified because it is so complex samples composed of different compounds that interact only with each other or causing synergistic effects. It was concluded that the dam Creek Waterfall, is contaminated with radon, as well as heavy metals, coliforms and chloride, causing toxic effects to the natural community. Thus, further studies should be performed with the human population of the region, to verify that the high rates of cancer in the population of the municipality may be linked to the presence of natural radiation. Thus, it is expected that the competent bodies that administer the municipality of Lajes Pintadas take reasonable steps to minimize risks and ensure the health of the community that still makes use of the weir