Síntese e caracterização de novos materiais compósitos orgânicos/inorgânicos, fotopolimerizáveis, para uso em restaurações odontológicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modelagem teórico-experimental de sistemas suspensos de secagem doméstica de vestuários

Pós-graduação em Engenharia Mecânica - FEG

Análise ergonômica de instrumentos líticos pré-históricos brasileiros: uma contribuição para a história da ergonomia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Obtenção e caracterização de filmes finos de Bi3NbO7 pelo método dos precursores poliméricos

Pós-graduação em Engenharia Mecânica - FEG

Influência da Espessura nas Propriedades Mecânicas de Compósitos Híbridos Interlaminares de Curauá/Vidro/Poliéster

The interest in the use of vegetable fibers (e.g. jute, sisal and curaua) for more noble applications, such as reinforcement in polymeric composite materials, has increased over the years due to a variety of aspects, especially those related to environmental legislation and community awareness regarding the life cycle of products. In this context, the aim of this work is to develop hybrid interlaminate curaua/glass/insaturated polyester composites by hot compression molding and to analyze their mechanical properties as a function of the thickness of the laminate. The short beam strength of the thickest sample decreased due to its higher void content. Furthermore, the thinnest sample showed lower hardness, and lower impact, tensile and Iosipescu shear strength, partly attributed to its lower fiber volumetric fraction. Thus, in general, the most adequate laminate was the one comprising eight layers, four of which were of glass fiber and four of curaua fiber, but only if flexural loading is not critical.

Photodegradation of phenol red on a Ni-doped niobate/carbon composite

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

Procedures to Evaluate the Efficiency of Protective Clothing Worn by Operators Applying Pesticide

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

TENSILE AND CREEP BEHAVIOR OF GEOSYNTHETICS USING CONFINED-ACCELERATED TESTS

A major aspect in geosynthetics creep analysis is the load level applied to the specimen, usually referred as a percentage of the geosynthetic ultimate tensile strength (UTS). Since both tensile and creep standard tests are performed with in-isolation specimens, they may not reproduce the possibly significant effect of soil-geosynthetic interaction. A new creep testing machine was recently developed and successfully addressed this concern. However, further developments allowed tensile tests to be performed in the same conditions used in nonconventional creep ones. This paper presents the results of nonconventional tensile tests performed with a woven biaxial polyester geogrid. They were used to define its UTS in the same conditions employed in creep tests performed with the new equipment. Despite changes in tensile curves shapes were found, the UTS from confined, accelerated and confined-accelerated tensile tests were quite similar to those obtained with standard tensile test procedure.

Involvement of the median preoptic nucleus in blood pressure control

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação in vitro da resistência adesiva ao cisalhamento entre a dentina bovina, cimentos resinosos e materiais restauradores indiretos, tratados ou não com jato de óxido de alumínio, ácido fluorídrico e silano

The purpose of this study was to evaluate in vitro the shear bond strenght to bovine dentin, during 24h and 30 days with the following variables: resin cements Enforce and Panavia F; aesthetics restorative materials Art Glass, IPS Empress 2 and Targis, with surface treatment with microetching with aluminium oxide, fluoridric acid and silane. Two hundred eighty eight sound bovine teeth from 3 years old animals constituted the samples after inclusion on polyester resin box. lnstron model 430 Universal Testing Machine, a crosshead speed 0,5 mm/min and load cells of 500 Kg, was used for shear bond strenght testing (MPa). The results were statistically analysed by ANOVA The best result was obtained with /PS Empress 2, microetched with aluminium oxide, fluoridric acid and silane, cemented with Panavia F and stored in distilled water, 3f'C during 30 days

Influence of monomeric and polymeric structure on the physical properties of thermoplastic polyesters derived from hydroxy fatty acids

The physical properties of three vegetable oil derived medium and long chain poly(-hydroxy fatty ester)s (P(Me--OHFA)s), namely poly(-hydroxynonanoate) [P(Me--OHC9)], poly(-hydroxytridecanoate) [P(Me--OHC13)] and poly(-hydroxyoctadecanoate) [P(Me--OHC18)] (n = 8, 12 and 17, respectively), of the [-(CH2)(n)-COO-](x) polyester homologous series are presented. The effect of M-n (M-n 10-40 kg mol(-1)) and n on the crystal structure and thermal and mechanical properties of the P(Me--OHFA)s were investigated by wide-angle X-ray diffraction (WAXD), TGA, DSC, dynamic mechanical analysis (DMA) and tensile analysis and are discussed in the context of the [-(CH2)(n)-COO-](x) polyester homologous series, contrasted with linear polyethylene (PE). For all P(Me--OHFA)s the WAXD data indicated an orthorhombic crystal phase reminiscent of linear PE with crystallinity (X-c = 50%-80%) depending strongly on M-n. The glass transition temperature and Young's modulus for P(Me--OHFA)s increased with X-c. The DSC, DMA and TGA studies for P(Me--OHFA)s (n = 8, 12 and 17) indicated strong correlations between the melting, glass transition and thermal degradation behavior and n. The established predictive structure relationships can be used for the custom engineering of polyester materials suitable for specialty and commodity applications. (c) 2014 Society of Chemical Industry

Suitability of carbon fiber-reinforced polymers as power cable cores: Galvanic corrosion and thermal stability evaluation

The increasing demand for electrical energy and the difficulties involved in installing new transmission lines presents a global challenge. Transmission line cables need to conduct more current, which creates the problem of excessive cable sag and limits the distance between towers. Therefore, it is necessary to develop new cables that have low thermal expansion coefficients, low densities, and high resistance to mechanical stress and corrosion. Continuous fiber-reinforced polymers are now widely used in many industries, including electrical utilities, and provide properties that are superior to those of traditional ACSR (aluminum conductor steel reinforced) cables. Although composite core cables show good performance in terms of corrosion, the contact of carbon fibers with aluminum promotes galvanic corrosion, which compromises mechanical performance. In this work, three different fiber coatings were tested (phenol formaldehyde resin, epoxy-based resin, and epoxy resin with polyester braiding), with measurements of the galvanic current. The use of epoxy resin combined with polyester braiding provided the best inhibition of galvanic corrosion. Investigation of thermal stability revealed that use of phenol formaldehyde resin resulted in a higher glass transition temperature. On the other hand, a post-cure process applied to epoxy-based resin enabled it to achieve glass transition temperatures of up to 200 degrees C. (C) 2014 Elsevier Ltd. All rights reserved.

Vagal afferent control of abdominal expiratory activity in response to hypoxia and hypercapnia in rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação de sistemas de pultrudados com diferentes tipos de matrizes para aplicação em cabos condutores

In the last decades it has been observed a substantial developing of the electrical energy demand in the societies all over the World. In consequence the electrical energy distribution companies are increasing the quantity of electrical energy through the electrical energy conductor cables, which had grown the sag in the towers of energy transmission. Furthermore, the construction of more transmission towers brings a lot of troubles due environmental protection laws. In this way, looking forward to increase the quantity of electrical energy transmitted through electrical cables conductors, reduce the need of constructing new transmission towers and the sag in them, we suggest in this work the replace of the traditional core of the conductors cables commonly used, made of steel, by a core made by a composite material, which one is made by carbon fibers pultruded with polymeric resins as matrix. In a order to evaluate if the resins more commonly used in structural composites can be applied as matrix to make possible to use the composite material as a core, we made carbon fibers systems pultruded with epoxy, phenolic and polyester resins as matrix and a mechanic and physic-chemistry characterization was done on the systems by Tensile and Poisson tests, differential sprobe calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transformed infrared spectroscopy (FTIR), following their correspondents standards

Síntese e caracterização de monômeros azo-carbonatos para a preparação de poli(azo-carbonato)s e poli)azo-uretana)s

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)