The self-healing behavior of radial cracks generated by Vickers indentation in float glass is analyzed when heat treated at 6201C under various atmospheres. Results evidence that two main driving forces influence radial crack evolution: release of residual stresses induced by initial indentation and capillary forces due to surface energy minimization. Depending on the viscosity level, viscous flow allows crack morphological changes driven by capillarity forces or not. Our results evidence that at 6201C, the viscosity of the glass surrounding cracks can be significantly reduced by water diffusion and glass hydrolysis, or increased by glass des-hydration, as a function of the humidity level of the furnace atmosphere. Hydration and des-hydration of glass are shown to play a major role in the crack morphology changes during healing, respectively, favoring or impeding morphological changes driven by capillarity forces.T. Rouxel-contributing editor

Dielectric properties of grapes at 2.45 GHz were measured at moisture contents varying from 80 to 15% (wet basis) at temperatures ranging from 25-80 degrees C using the Open Ended Coaxial Transmission Line Technique. Both dielectric constant and loss factor decreased with decreasing moisture content. In low moisture samples these properties were found to be considerably influenced by higher temperatures. Dielectric properties of sugar solutions of varying concentrations (20-250% by weight in water) were also determined at different temperatures, and these values were compared to those of grapes of corresponding moisture concentration. Predictive models of the dieletric properties as functions of moisture content and temperature were generated using response surface methodology. The results are useful in estimating the volumetric heating of grapes by microwave energy, and these methods can be extended to sugar-based foods in general.

The evolution of radial cracks generated by Vickers indentation on “tin side” of float glass is analysed when heat treated at 620°C under various atmospheres and results are compared with a previous similar study performed on the “air side” of the same glass. Results evidence that the presence and the oxidation state of tin ions has a strong influence on crack morphological changes. If the oxidation state of tin remains quasi unchanged during the heat treatment, the mechanism responsible of the crack evolution is the spheroidization and there is no strong difference between the crack morphological changes observed on the “air” and “tin side” in this case. For oxidative atmospheres, contrary to what is observed on the “air side”, no crack spheroidization occurs. The cracks stay quasi unchanged for dry air or close for humid air. Increase of the viscosity at the top surface due to Sn oxidation is proposed to explain this spheroidization impediment. It is also shown that in these two cases, there is an efficient blunting and healing of the cracks, as four point bending tests indicate a significant sample strengthening with thermal treatment

In the coming years, incremental automation will be the main challenge in the development of highly versatile helicopter technologies. To support this effort, vision-based systems are becoming a mandatory technological foundation for helicopter avionics. Among the different advantages that computer vision can provide for flight assistance, navigation in a GPS-denied environment is an important focus for Airbus because it is relevant for various types of missions. The present position paper introduces the different available SLAM algorithms, along with their limitations and advantages, for addressing vision-based navigation problems for helicopters. The reasons why Visual SLAM is of interest for our application are detailed. For an embedded application for helicopters, it is necessary to robustify the VSLAM algorithm with a special focus on the data model to be exchanged with the autopilot. Finally, we discuss future decisional architecture principles from the perspective of making vision-based navigation the 4th contributing agent in a wider distributed intelligence system composed of the autopilot, the flight management system and the crew.

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