The durability of materials exposed to corrosive conditions is a major stake as it affects process and plant safety and implies large costs. In real applications and in future “zero emission technologies”, metallic alloys are and will be subjected to oxidizing and water-rich environments at high temperature. Under such conditions, the volatilization of the chromia scale takes place, speeding up the material end of life. While the chromium loss due to volatilization has been estimated many times to assess the material lifetime in past and recent studies, the gas phase evolution and its influence on the volatilization rate are rarely considered although they affect the alloy end of life. To respond to such problem, the DYNAMIC project, which associate 3 academic labs with 2 industries, proposes to evaluate the high temperature oxidation of refractory metallic alloys and the volatilization of their protective oxide layer by an original approach combining high temperature oxidation tests and simulations of the gas phase. Oxidation tests will be carried out between 600 and 1100 °C, under intermediate to high gas velocities (from few tens of cm.s-1 to few m.s-1) and over the complete water vapour content range, i.e. from few ppm to nearly 100 %. Also, characterizations of the samples, before and after oxidation, will be performed. In parallel, the gas phase within the oxidation rigs and the volatilization reaction will be simulated by computational fluid dynamics (CFD). This methodology will be conducted to better understand the influence of dynamic flows on oxidation and volatilization kinetics, and therefore the degradation mechanisms at work in such environments. It shall make it possible the determination of laws capable of predicting lifetime and the evaluation of the effects of geometry to propose solutions to delay the end of life of alloys.

The master planning of sustainable urban nightscapes requires a parsimonious use of artificial light at night (ALAN) to meet societal needs for safety, mobility, economic and social life, while limiting energy consumption, and negative impacts for humans, for the climate and for biodiversity. But in order to promote light sobriety, lighting modifications must be acceptable to the public, and technically feasible. As the suppression of ALAN is not always an acceptable option, it is necessary to understand the constraints and the needs of the different actors in order to promote sustainable urban lighting. The development of Smart Cities and the possibilities brought by the LED technology opens up new strategies to reduce ALAN while controlling its impact on ecosystems and on the quality of life. The LUNNE project addresses several scientific challenges associated with the reduction of ALAN: 1) A more appropriate quantification of the impact of ALAN reduction strategies on ecosystems, through the development of new indicators at different spatial scales. 2) A better knowledge and quantification of the impact of these strategies on people (mobility, safety, nightlife). 3) A better understanding of the obstacles and levers to the acceptability of these urban lighting policies. All three dimensions will merge into multi-factor indices and specific methodologies, providing urban communities with decision-making tools to consider the specificities of their territory when they adapt their lighting. The impact of lighting modifications will be studied by combining the collection of behavioural data in urban observatories, the collection of subjective and social data through surveys, the collection of photometric data through measurements, and the implementation of computational models.