Effect of structure on tribomechanical properties of sintered (Al-12Si)-Sn composites

The structure, mechanical and tribological properties of sintered (Al-12Si)-xSn composites were investigated in the present study. The composites were obtained by sintering of the briquettes made of aluminum (Al-12Si) and tin powders mixture. It was found that the hot densification substantially increases the strength of sintered composites and also makes much higher their wear resistance under the dry friction against a steel counterbody. The mechanical properties of the obtained materials slowly decrease with an increasing of tin content up to 40 wt. %, while their wear resistance increases

Electrical conductivity and gas-sensing properties of Mg-doped and undoped single-crystalline In 2 O 3 thin films: bulk vs. surface

This study aims to provide a better fundamental understanding of the gas-sensing mechanism of In2O3-based conductometric gas sensors. In contrast to typically used polycrystalline films, we study single crystalline In2O3 thin films grown by molecular beam epitaxy (MBE) as a model system with reduced complexity. Electrical conductance of these films essentially consists of two parallel contributions: the bulk of the film and the surface electron accumulation layer (SEAL). Both these contributions are varied to understand their effect on the sensor response. Conductance changes induced by UV illumination in air, which forces desorption of oxygen adatoms on the surface, give a measure of the sensor response and show that the sensor effect is only due to the SEAL contribution to overall conductance. Therefore, a strong sensitivity increase can be expected by reducing or eliminating the bulk conductivity in single crystalline films or the intra-grain conductivity in polycrystalline films. Gas-response measurements in ozone atmosphere test this approach for the real application

Dagstuhl-Manifest zur Strategischen Bedeutung des Software Engineering in Deutschland

Im Rahmen des Dagstuhl Perspektiven Workshop 05402 "Challenges for Software Engineering Research" haben führende Software Engineering Professoren den derzeitigen Stand der Softwaretechnik in Deutschland charakterisiert und Handlungsempfehlungen für Wirtschaft, Forschung und Politik abgeleitet. Das Manifest fasst die diese Empfehlungen und die Bedeutung und Entwicklung des Fachgebiets prägnant zusammen