Development of a non-destructive method for underglaze painted tiles – demonstrated by the analysis of Persian objects from the nineteenth century.

The paper presents an analytical method developed for the nondestructive study of nineteenth-century Persian polychrome underglaze painted tiles. As an example, 9 tiles from French and German museum collections were investigated. Before this work was undertaken little was known about the materials used in pottery at that time, although the broad range of colors and shades, together with their brilliant glazes, made these objects stand out when compared with Iranian ceramics of the preceding periods and suggested the use of new pigments, colorants, and glaze compositions. These materials are thought to be related to provenance and as such appropriate criteria for art-historical attribution. The analytical method is based on the combination of different nondestructive spectroscopic techniques using microfocused beams such as proton-induced X-ray emission/proton-induced γ-ray emission, X-ray fluorescence, 3D X-ray absorption near edge structure, and confocal Raman spectroscopy and also visible spectroscopy. It was established to address the specific difficulties these objects and the technique of underglaze painting raise. The exact definition of the colors observed on the tiles using the Natural Color System®© helped to attribute them to different colorants. It was possible to establish the presence of Cr- and U-based colorants as new materials in nineteenth-century Persian tilemaking. The difference in glaze composition (Pb, Sn, Na, and K contents) as well as the use of B and Sn were identified as a potential marker for different workshops

Potential of microalgae biomass for the sustainable production of bio-commodities

Human activities are causing major negative environmental impacts, and the development of sustainable processes for production of commodities is a major urgency. Plant biomass represents a valuable alternative to produce energy and materials, but exploiting present crops for commodities production would however require massive resources (i.e. land, water and nutrients), raising serious sustainability concerns. In addition to efforts to improve plant, land and resource use efficiency, it is thus fundamental to look for alternative sources of biomass to complement crops. Microalgae are unicellular photosynthetic organisms that show a huge, yet untapped, potential in this context. Microalgae metabolism is powered by photosynthesis and thus uses sunlight, a renewable energy source, and the exploitation of microalgae-based products has the potential to provide a beneficial environmental impact. These microorganisms have the ability to synthesize a wide spectrum of bioactive compounds, with many different potential applications (e.g. nutraceutics/pharmaceutics and biofuels). Several, still unresolved, challenges are however present such as the lack of cost-effective cultivation platforms and biomass-harvesting technologies. Moreover, the natural metabolic plasticity of microalgae is not optimized for a production at scale, and low biomass productivity and product yields affect competitiveness. Tuning microalgae metabolism to maximize productivity thus represents an unavoidable challenge to reach the theoretical potential of such organisms