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Direct methanol fuel cells (DMFC) have major technical problems, e.g. slow methanol oxidation kinetics and high methanol crossover, to use as power sources for several applications. To overcome these problems it has been proposed to increase the fuel cell operating temperature to over 100–150 °C and to reduce the methanol permeability.In this work, we made Nafion®/montmorillonite (MMT) nanocomposite membranes and carried out diverse tests. The nanocomposite membranes were produced by direct melt intercalation of perfluorosulfonylfluoride copolymer resin (Nafion® resin) into the montmorillonite and modified montmorillonite (m-MMT) which was organized by dodecylamine. The membrane–electrode assembly (MEA) has been made using a hot pressing method and the electrode prepared using PtRu black and Pt black catalysts for anode and cathode, respectively.The morphology of the nanocomposite membranes has been investigated using SEM and TEM. The nanocomposite membranes and MMT and m-MMT were analyzed using by FT-IR and X-ray diffraction (XRD). The thermal and mechanical properties of those membranes were also investigated and the methanol permeability was measured by gas chromatography (GC). The performance of the MEA using the nanocomposite membrane was evaluated by single cell test. The results show that the performance of the MEA using the nanocomposite membrane was higher than that of a commercial Nafion® membrane at high operating temperature. [Copyright &y& Elsevier]

We developed an ac microcalorimeter utilizing the Peltier effect of a thermocouple junction as an ac power source. This Peltier microcalorimeter allows us to measure the absolute value of the heat capacity of small samples with submilligrams of mass. The performance of the microcalorimeter was checked in the temperature range of 15-420 K with α-Al[sub 2]O[sub 3] samples of 0.54 and 2.25 mg. The absolute accuracy was ±3% for the range of 30-150 K and ±1% for 150-420 K. The precision was better than 0.5% in the whole temperature range. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: It was shown in the previous study that the fracture toughness of dried carbon/epoxy composites increased 38% as the applied hydrostatic pressure increased from 0.1 to 200MPa. However, no research has been conducted on the fracture behavior of seawater-absorbed carbon/epoxy composites in a hydrostatic pressure environment. This work investigates the compressive fracture behavior of seawater-absorbed carbon/epoxy composites subjected to various hydrostatic pressures. Compressive fracture tests were performed under four hydrostatic pressure levels, 0.1 (atmospheric pressure), 100, 200, and 270MPa. The compliance and fracture loads were determined from load–displacement curves as a function of hydrostatic pressure. Fracture toughness was determined from the elastic work factor approach. The results showed that compliance decreases but fracture load increases as the applied hydrostatic pressure increases. Fracture toughness increased with increasing pressure. Specifically, fracture toughness increased from 2.66 to 4.44kJ/m2, a 67% increase, as hydrostatic pressure increased from 0.1 to 270MPa. Optical microscope examination of the fractured surface showed that local delaminations and microcracks are suppressed with increasing hydrostatic pressure. SEM examination showed that seawater-absorbed specimen shows a lot more epoxy fracture than the dried specimen. [Copyright &y& Elsevier]