This project exploits the capacities of a high cooling power refrigerator for implementing a large dimensions von Karman flow (diameter 80 cm), working as well with liquid or gaseous helium, as with superfluid. Von Karman flow is producted between two parallel contrarotating disks. It is now well documented. Recent progress has been realised on the understanding of the mean flow structures. Depending on the location, it presents either a reasonable example of homogeneous isotropic turbulence, or an interesting case of strong anisotropy. P. Tabeling et al. already used cryogenic helium in a von Karman flow, and obtained the main known results on superfluid turbulence. A traditional weak point of cryogenic turbulence experiments is the small number of available probes. We shall develop an original instrumentation (hot wire, second sound tweezers, acoustic scattering, ...) allowing to probe the flow at any scale, from the mean flow to sub-inertial scales. Comparing the normal and super-fluid behaviours in the same geometry will provide an original way to test some controversed ideas about turbulence. An asset to this ambitious project is that each participant is interested in everything, from the design of the experiment to the results analysis.

The lack of fossil fuels (oil, coal and natural gas) associated with growing energy needs of human populations, lead to increased costs of these energies. Moreover, their massive use causes environmental problems (air pollution, greenhouse effect etc ...) strongly affecting life conditions and health of populations. In this context of renewable energies promotion and gas emissions reduction the bottleneck of electricity storage is one of the biggest challenge that we have to address. One of the obstacles in transportation (urban or military) is the use of autonomous electrical power sources (rechargeable batteries, fuel cells, etc.). These devices do not allow for high enough specific powers, needed for the different type of applications they are expected for and limit their dynamical performances. For several years, developments have been achieved and have led to the development of ultracapacitors. These components are characterized by much higher specific energies compared to classical capacitors as well as higher specific powers compared to electrochemical batteries. However, their specific energy remains lower than batteries by a factor of 10 to 30. In this context, this fundamental project deals with the development of new high energy density hybrid ultracapacitors for specific applications both in the military and civil field. The development of new materials with improved specific capacitance associated with an increase in the potential difference applied during charging aims at increasing the performance in terms of energy density while maintaining a high power density. To do this, we will develop new pseudocapacitive positive electrode materials based on vertically aligned carbon nanotubes (VACNT) modified by electronic conducting polymers (ECP) and/or manganese oxide electrodeposited in a controlled manner. These new nanostructured electrodes will be associated within symmetric or asymmetric configuration with classical graphite electrode or titanate ones in order to ensure large charge-discharge currents and reach high power electrochemical hybrid ultracapacitors. Moreover this project reveals a high economical potential with the demonstration of low cost large surface VACNT production that will be exploited very soon by the NAWATechnologies Company under creation. That is why we propose, at the end of the project, the fabrication of a 10*10 cm2 ultracapacitor prototype using the best configuration to demonstrate industrialization feasibility of the concept.

The central Sahara has one of the most extreme climates on Earth. During the northern summer months, a large low pressure system caused by intense solar heating develops over a huge, largely uninhabited expanse of northern Mali, southern Algeria and eastern Mauritania. This Saharan heat low plays a pivotal role in the West African Monsoon. Moreover, the Saharan heat low region is dynamically coupled with the Mediterranean basin and the Sahel, two regions for which the predicted uncertainties associated with the impact of global forcing are quite significant. This large zone is also where the thickest layer of dust anywhere in the Earth’s atmosphere is found. The direct and indirect effects associated with desert dust are still poorly quantified, and the biases and errors affecting the radiative budgets in models over the Sahara are very important. It is known that such errors in modelled dust radiatif effects lead to errors in key dynamical features beyond the Sahara, with consequences for tropical development in the Atlantic and the circulation over the Mediterranean basin. The failure of climate models or numerical prediction models to capture main features of the Saharan weather is related to (i) the paucity of available data in this region, (ii) the difficulty to retrieve reliable space-borne “aerosol” products over deserts, and (iii) a lack of knowledge regarding the dynamics, thermodynamics and radiative processes in the Saharan atmosphere. To date, there exist very sparse data sources in this region that can be used reliably to enhance knowledge in terms of mesoscale processes or model validation. Large uncertainties remain regarding the position of dust sources, the quantity and the properties of mineral dust emitted the albedo variability at the mesoscale and the impact of aerosol radiative forcing on the atmospheric dynamics in the region. Such uncertainties can only be thoroughly evaluated, and hopefully reduced, in the framework of an ambitious project aiming to make decisive progress in terms of dynamics, thermodynamics and on the structure and composition of the Saharan atmosphere, by means of observations over the Sahara. Based on this, the interested French, British and German communities have decided to propose the FENNEC project which aims at (i) characterizing the Saharan atmospheric boundary layer, (ii) evaluating its representation in regional and global models, and (iii) improving “aerosol” products issued from space-borne observations. A key element of this programme is the organization of an international field campaign in the Saharan heat low region, which will include both ground-based and airborne detachments. On important aspect of this proposal, which aims at enhancing the knowledge of processes controlling the Saharan climate system, is to provide a framework for the French groups eager to contribute to this type of research and to ask for the means for achieving the proposed goals. The FENNEC-France proposal is built on contributions from 11 laboratories. The project benefits from support at the international level, amongst which support from the WMO program “Sand and Dust Storms Warning Advisory Assessment System” and the African Center of Meteorological Application for Development” (ACMAD).