A degradação térmica a 300 ºC de argamassas de cimento Portland reforçada por fibras de polipropileno foi investigada. Foi proposto um modelo computacional para a avaliação qualitativa da conectividade da estrutura de poros. Os resultados revelaram a degradação das argamassas com a temperatura dos tratamentos térmicos. A conectividade da estrutura de poros aumentou com a temperatura do tratamento térmico para as argamassas com fibra. Os resultados também mostraram um aumento da conectividade da estrutura de poros para as argamassas com fibra não submetidas à alta temperatura.

Thermal degradation at 300 ºC of polypropylene fiber reinforced Portland cement mortars was investigated. A geometric modeling considering pore with cylindrical shape was also used in order to do quantitative evaluation of pore structure's connectivity. The results revealed thermal degradation of the mortars by high temperature. The pore structure connectivity increased with thermal treatment temperature for mortar samples with fiber content. The test results also showed pore structure connectivity increase for non-heat treated fibered mortars.

A céria contendo 20% mol samária é um eletrólito sólido proposto para uso em células a combustível de óxido sólido que operam em temperaturas intermediárias (~500 a 700 ºC), devido sua alta condutividade iônica. Um dos fatores limitantes para isto é sua relativamente baixa sinterabilidade. Neste trabalho foram utilizados dois métodos alternativos de sinterização com a finalidade de obter amostras densas, microestrutura homogênea e tamanho de grãos controlado. Outro objetivo foi relacionar os efeitos observados na microestrutura e na densificação com a condutividade elétrica das amostras sinterizadas. Para isto foi utilizada a Ce0,8Sm0,2O1,9 comercial, conformada uniaxial e isostaticamente, e sinterizada ao ar. As amostras sinterizadas foram analisadas por diversas técnicas. Resultados de medidas da densidade aparente revelaram que ambos os métodos são eficazes para a obtenção de cerâmicas com densidade relativa superior a 92%. A condutividade elétrica dos grãos e dos contornos de grão são também similares nas diversas amostras estudadas, apesar dos tamanhos dos grãos serem diferentes.

Ceria containing 20 mol% samaria is a solid electrolyte with potential application in solid oxide fuel cells operating at intermediate temperatures (~500 to 700 ºC) due to its high ionic conductivity. One of the main concerns related to this solid electrolyte is the relatively low sinterability. In this work, two alternative sintering methods were used to obtain ceramic samples with high density, homogeneous microstructure and controlled grain size. Other purpose of this work was to correlate the observed effects in the microstructure and densification with the electrical conductivity of sintered samples. Commercial Ce0.8Sm0.2O1.9 was used as starting material. The consolidation was accomplished by uniaxial and isopressing followed by sintering in air. Several techniques were used for sample characterization. Apparent density results revealed that both sintering methods were able to produce samples with relative density higher than 92%. The electrical conductivity of grains and grain boundaries were similar in these samples, although different grain sizes were obtained.

The aim of the present investigation was to describe and validate an electronic mechanical test for quantification of the intensity of inflammatory nociception in mice. The electronic pressure-meter test consists of inducing the animal hindpaw flexion reflex by poking the plantar region with a polypropylene pipette tip adapted to a hand-held force transducer. This method was compared to the classical von Frey filaments test in which pressure intensity is automatically recorded after the nociceptive hindpaw flexion reflex. The electronic pressure-meter and the von Frey filaments were used to detect time versus treatment interactions of carrageenin-induced hypernociception. In two separate experiments, the electronic pressure-meter was more sensitive than the von Frey filaments for the detection of the increase in nociception (hypernociception) induced by small doses of carrageenin (30 µg). The electronic pressure-meter detected the antinociceptive effect of non-steroidal drugs in a dose-dependent manner. Indomethacin administered intraperitoneally (1.8-15 mg/kg) or intraplantarly (30-300 µg/paw) prevented the hypersensitive effect of carrageenin (100 µg/paw). The electronic pressure-meter also detected the hypernociceptive effect of prostaglandin E2 (PGE2; 10-100 ng) in a dose-dependent manner. The hypernociceptive effect of PGE2 (100 ng) was blocked by dipyrone (160 and 320 µg/paw) but not by intraplantar administration of indomethacin (300 µg/paw). The present results validate the use of the electronic pressure-meter as more sensitive than the von Frey filaments in mice. Furthermore, it is an objective and quantitative nociceptive test for the evaluation of the peripheral antinociceptive effect of anti-inflammatory analgesic drugs, which inhibit prostaglandin synthesis (indomethacin) or directly block the ongoing hypernociception (dipyrone).