Acoustic discretion is an important problem in the field of naval operations for new ships as well as in the air domain, for example for planes, rail cars... More particularly, the RAMSES project deals with the noise radiated by periodically stiffened metallic structures when they are excited either by pressure fluctuations of the turbulent boundary layer or by mechanical vibrations (in a frequency range below 2kHz, for a typical submarine). The purpose is to eliminate or reduce significantly the radiation of the Bloch-Floquet waves created by the stiffener periodicity. Several solutions are proposed: (1) classical solution based on resonant systems, made of viscoelastic materials and additional masses, as those considered in the ASTRID FARAON project (Acoustic stealth by resonating stiffeners, 04/2014-09/2016, handled by Mr. Tran Van Nhieu from Thales RT) with the aim of controlling the stealth of stiffened plates or shells, (2) solution with passive metamaterials to allow for resonance frequency tuning on a wide range by simply modifying the effective properties of the metamaterials constituting the resonant systems, (3) solution with piezoelectric materials connected to a very simple electronic circuit (short circuit, open circuit or positive capacitance) with the aim of modifying by a simple external electric command the properties of each resonant system independently, (4) semi-active solutions with piezoelectric materials connected to a complex electronic circuit with a negative capacitance or a blind switch damping for instance, usually used for vibration damping or energy harvesting. The last two solutions are innovative strategies for the control of the acoustic radiation in break with the previously proposed solutions because they will allow variable jamming by modifying in real time the electric connections of the active materials. The developed analytical and numerical models will be implemented to design and optimize systems for acoustic radiation control corresponding to realistic configurations in line with naval concerns. Four plates equipped with stiffeners and resonant systems will be manufactured at the 1/100 scale and tested, in connection with each of the proposed solutions. The project will also aim at adapting the proposed solutions to periodically stiffened cylindrical shells. The skills linked with the project are analytical, numerical, as well as experimental with measurements in air and in water to estimate both plate vibration and far-field acoustic radiation reductions. Moreover, the proposed solutions present the advantage of handling both discretion and stealth simultaneously in the range of low frequencies, where the usual hull coating solutions are generally less efficient. This project is part of research topics n°3 " acoustic and radio waves" and n°2 " Fluids, structures ", and in the research priority for 2016: "new materials to optimize the radiation of antennas and stealth". The project is handled by IEMN (UMR 8520 CNRS) which has an internationally recognized expertise in passive and active metamaterials, as well as in modelling, with the help of Thales RT for the study, the choice and the manufacturing of the resonant structures, the LOMC for the manufacturing of scale models and the acoustic tests in water tank and Thales US for the finite element numerical models and for its expertise in underwater acoustics.

In the context of maritime surveillance or anti-submarine warfare, knowledge of the acoustic field radiated or diffracted by an object submerged in water is of essential importance for its operational or tactical use, as well as for its design. Among the means of surveillance, in water, there are active and passive sonar devices. A passive sonar system is a system that exploits the noise radiated by the craft (submersible ship, surface vessel, drone, etc.) that it seeks to detect. These radiated noises are generated by the existing machinery on board, the phenomenon of cavitation, hydrodynamic flows, impulsive and transient sources ... By contrast, an active detection system in underwater acoustics emits a specific signal in the direction of a target, then listen and process the echoes that come back to it. The SURCOUF project focuses on the study of the effects of the sea surface on the acoustic radiation and scattering of resonant objects submerged at relatively shallow depth. The object considered for the study, representative of a naval structure, is a cylindrical shell, stiffened or not, limited by flat or hemispherical caps. The main objective of this project is to evaluate experimentally and numerically the influence of the free surface on the acoustic signatures of these shells for different depths of immersion, by taking into account the acoustic contributions induced by the proximity of the free surface and those linked to the specific response of the studied object. This study is oriented along two axes: analysis in monostatic diffusion in an azimuthal plane, on the one hand, analysis in acoustic radiation (internal excitation of the shell), on the other hand. The analysis of the acoustic signature of these shells for these two types of excitation will provide a good understanding of the physics of the phenomena involved. This topic also fits into the environmental context of monitoring ambient underwater noise. It is indeed necessary to precisely characterize the noise radiated by sound sources present in a maritime area in order to be able to map the underwater acoustic field in the area under consideration and to assess the impact of human activities on marine fauna. For sound sources close to the surface, one must understand the impact of the proximity of the free surface on the sound field they radiate.

This project aims to improve our knowledge of the transfer and toxic effects of mercury from phytoplankton to mussel using both chemical and molecular biology cutting edge approaches. The project will answer to the following questions: (i) do MMHg and IHg follow a similar transfer rate in mussels fed with diatoms or chlorophytes showing contrasted cell walls, (ii) does the proportion of diatoms in phytoplankton inversely correlate with Hg transfer in mussels? (ii) Does the subcellular fate of IHg and MMHg differ in waterborne and dietary exposures? (iii) Does molecular, cellular and individual response of IHg and MMHg differ in waterborne and dietary exposures? (iv) Can we statistically and biologically link an omic signature with apical effects in an exposome context? (v) Do Mytilus edulis and Dreissena polymorpha show similar responses to Hg exposure? Once these questions deciphered, we will use the data to further propose omic signatures of exposure and effect for improved monitoring of the flux and impact of contaminants through ecosystems. This fundamental knowledge is essential to better understand and predict the propagation of effects between trophic levels of aquatic systems and to identify innovative and more efficient biomarkers for improved risk assessment of contaminants.

Despite a constant increase in plastic worldwide production, the environmental risk linked to microplastics remains little studied today. The PLASTERA project aims to define this risk in a global pollution context in the Loire River and its estuary, while considering environmental, animal and human health. This project will be divided into four phases: i) to characterize the plastic exposome in the Loire River and its estuary, ii) the use of an active biomonitoring approach to assess its effects on various sentinel species, iii) to characterize the effects of these environmental contaminants from bivalves to humans at sub-individual levels and iv) to provide data to help regulation of this emerging contamination while raising citizen awareness of this contamination. This project aims to be in line with the "One Health" concept considering environmental health (determination of contamination and its effects at the level of four habitats: freshwater / marine water / benthic / endobenthic), animal and human health (in situ exposures of sentinel species in these habitats and in vitro exposures of animal and human immune cells). The new IBR-T index (integrative biomarker responses) will be deployed to summarize the effects of this contamination and raise awareness of the general public, communities and other stakeholders.

Every year, the number of urban residents is growing. Diverse questions related to sustainability are rise from this growth. For example, for large and attractive territories, which urban planning policies to implement? How to manage and prevent technological or environmental hazards? Decision makers have to take all of these issues into account when defining their urban planning policies. Unfortunately, the assessment of the impacts of possible policies is difficult due to the complex and stochastic interplay between society and infrastructure. One of the most promising approaches to face this difficulty is agent-based modeling. This approach consists in modeling the studied system as a collection of interacting decision-making entities called agents. An agent-based model can provide relevant information about the dynamics of the real-world urban system it represents. Moreover, it can allow to be used as a virtual laboratory to test new urban planning policies. The use of agent-based models to study urban systems is booming for the last ten years. Another tendency is the development of more and more realist models. However, if models have make a lot of progresses concerning the integration of geographical and statistical data, the agents used to represent the different actors influencing the dynamic of the system (inhabitants, decision makers...) are often simplistic (reactive agents). Yet, for some urban models, being able to integrate this cognitive agents, i.e. agents able to make complex reasoning such as planning to achieve their goals, is mandatory to improve the realism of models and test new scenarios. Unfortunately, developing large-scale models that integrates cognitive agents requires high-level programming skills. Indeed, if there are nowadays several software platforms that propose to help modelers to define their agent-based models through a dedicated modeling language (Netlogo, GAMA…) or through a graphical interface (Starlogo TNG, Modelling4All, Repast Symphony, MAGéo...), none of them are adapted to the development of such models by modelers with low level programming skills: either they are too complex to use (Repast, GAMA) or too limited (Netlogo, Starlogo TNG, Modelling4All, Repast Symphony, MAGéo). As a result, geographers and urban planners that have no programming skills have to rely on computer scientists to develop models, what slows the development and the use of complex and realist spatial agent-based models. The objective of the ACTEUR project is to develop to help modelers, in particular geographers and urban planners, to design and calibrate through a graphical language cognitive agents able to act in a complex spatial environment. The platform has also for ambition to be used as a support of model discussion -participatory modeling- between the different actors concerned by a model (geographers, sociologists, urban planners, decision makers, representatives…). These tools will be integrated in the GAMA platform that enables to build large-scale models with thousands of hundreds of agents and that was already used to develop models with cognitive agents. In order to illustrate the utility and the importance of the developed tools, we will use them on two case studies. The first concerns the urban evolution of La Réunion island. The second case study will focus on the adaption to industrial hazards in Rouen. These two case studies are part of funded projects carried out by partners of the ACTEUR project.