an application of cosmo sky med to coastal erosion studies

AbstractStarted in 2009, the COSMOCoast project aims to the investigation of the potential of Remote Sensing in support to the management of coastal areas. Particular attention is paid to the contribution of data acquired from the COSMO-SkyMed constellation, in view of their frequency of acquisitions and ground resolution; in particular this paper aims at assessing the potential of COSMO-SkyMed data for coastline delineation. The results are conceived to be of particular interest for public administration bodies in charge of coastal defense. Keywords: Remote Sensing, Coastal Zones Management, COSMO-SkyMed

Aluminum concentration range for the extrudability of ceramic pastes

International audienceWith the goal of developing refractory pastes to replace metal alloys used in turbine blades for Deep Space exploration, the French Space Agency, CNES, in collaboration with the Institute of Research for Ceramics, IRCER, has developed a preliminary research where dense alumina ceramics were formulated, printed and tested. This preliminary research will be the prelude to substituting by materials with more interesting creep properties at high temperature, for example, yttrium aluminum garnet, YAG. Since alumina is less expensive than YAG, preliminary tests were performed with alumina. These alumina pastes were 3D-printed by robocasting from very high solid loaded alumina pastes (>75 wt%), in the presence of organic additives, namely glycerol, PVA and ISOBAM 104. Several formulations of pastes were prepared, with the aim to obtain dense ceramic pieces. After, the alumina and the organic additives were mechanically mixed and the pastes were extruded with a commercial 3D printer. The best sample was obtained with a paste presenting an Al2O3 solid load of 79.37 wt% (63.5 vol%). A debinding step was performed afterwards to eliminate their organic content and the consolidation of the shaped pieces was finally achieved by sintering at 1700°C. A % shrinkage of 8, 6.8 and 13.8 in the X, Y and Z-axes was measured, being one of the lowest values at 1700 °C compared to those in the literature

Synthesis and robocasting of YAG xerogel: one-step conversion of ceramics

International audienceAbstract An optimized sol–gel protocol was carried out to produce an yttrium aluminum garnet (YAG) xerogel from aluminum alkoxide and an yttrium salt on a semi-pilot scale. This xerogel was successfully used without prior pyrolysis as a solid load with the aid of additives in the preparation of pastes. Thermal treatment of the green bodies, obtained by robocasting of the paste, led to cohesive single-phase YAG ceramics. Manufacturing ceramic pieces by additive methods will allow shaping complex forms, while the single step conversion/consolidation would simplify the technological process, reducing global energy costs. Since YAG possesses high strength and good creep behavior at high temperatures, these refractory pieces could replace the metal alloys used in turbine blades for deep space exploration. Structural, thermal and chemical characterizations were performed on xerogel powders, pastes, and YAG ceramics

Sol-gel synthesis of yttrium aluminum garnet (YAG): effects of the precursor nature and concentration on the crystallization

International audienc

REMOTE SENSING AS A TOOL TO MONITOR AND ANALYSE ABRUZZO COASTAL CHANGES: PRELIMINARY RESULTS FROM THE ASI COSMOCOAST PROJECT

A clear view of actual and past processes affecting coastal areas at local and regional scale is the essential starting point to identify trends, issue forecasts and plan any protective measure. When this is not achieved, local interventions (eg breakwaters, groynes) may simply transfer the problem to adjacent areas, calling for further remedial measures and additional costs: this has happened since the 90’s along the Abruzzo coasts (Italy, Adriatic sea). In low coastal areas, the simplest parameter which can be monitored as proxy of the very complex dynamic equilibrium between mean sea level height, tide/wave energy and amount of incoming sediment is the shoreline, defined as the instantaneous divide between water and land. It has to be noted that even small tidal variation in such low relief areas can affect by several meters the position of the water divide: for cartographic purposes tidal and geomorphologic information is needed to correct for such effect. The COSMOCoast project, carried within the framework of an ASI contract (I/067/09/0), is applying standard image processing, object-oriented approaches and neural nets for boundary detection along the Abruzzo coast from high to very high resolution actual satellite data (eg COSMO-SkyMed, Formosat-2, IKONOS, Kompsat 2, Prism, Quickbird). The temporal observation window is extended backwards by a decade by exploiting older data at a much lower resolution (ERS). Validation data are provided by a kinematic GPS as well as by a ground lidar campaign carried out simultaneously to satellite overpass. Boundary-extraction tests run on COSMO-SkyMed spotlight acquisitions taken with different polarisations and incidence angles have been carried out: the NN outperformed the traditional techniques (based on Sobel’s and Robert’s operators) both in terms of accuracy detection and of computational burden. Segmentation of optical data acquired by different satellites also provide very good results. A second acquisition campaign is foreseen for 2011, whilst all processing results are being ingested in a GIS for quality and accuracy checking, validation, analysis of changes and definition of indicators