Multifractal Analysis of inhomogeneous Bernoulli products

We are interested to the multifractal analysis of inhomogeneous Bernoulli products which are also known as coin tossing measures. We give conditions ensuring the validity of the multifractal formalism for such measures. On another hand, we show that these measures can have a dense set of phase transitions

Coastal sea level monitoring in the Mediterranean and Black seas

Employed for over a century, the traditional way of monitoring sea level variability by tide gauges – in combination with modern observational techniques like satellite altimetry – is an inevitable ingredient in sea level studies over the climate scales and in coastal seas. The development of the instrumentation, remote data acquisition, processing, and archiving in the last decades has allowed the extension of the applications to a variety of users and coastal hazard managers. The Mediterranean and Black seas are examples of such a transition – while having a long tradition of sea level observations with several records spanning over a century, the number of modern tide gauge stations is growing rapidly, with data available both in real time and as a research product at different time resolutions. As no comprehensive survey of the tide gauge networks has been carried out recently in these basins, the aim of this paper is to map the existing coastal sea level monitoring infrastructures and the respective data availability. The survey encompasses a description of major monitoring networks in the Mediterranean and Black seas and their characteristics, including the type of sea level sensors, measuring resolutions, data availability, and existence of ancillary measurements, altogether collecting information about 240 presently operational tide gauge stations. The availability of the Mediterranean and Black seas sea level data in the global and European sea level repositories has been also screened and classified following their sampling interval and level of quality check, pointing to the necessity of harmonization of the data available with different metadata and series in different repositories. Finally, an assessment of the networks' capabilities for their use in different sea level applications has been done, with recommendations that might mitigate the bottlenecks and ensure further development of the networks in a coordinated way, a critical need in the era of human-induced climate changes and sea level rise.En prens

Lyapunov spectrum of asymptotically sub-additive potentials

For general asymptotically sub-additive potentials (resp. asymptotically additive potentials) on general topological dynamical systems, we establish some variational relations between the topological entropy of the level sets of Lyapunov exponents, measure-theoretic entropies and topological pressures in this general situation. Most of our results are obtained without the assumption of the existence of unique equilibrium measures or the differentiability of pressure functions. Some examples are constructed to illustrate the irregularity and the complexity of multifractal behaviors in the sub-additive case and in the case that the entropy map that is not upper-semi continuous.Comment: 44 page

The RONSARD radars : a versatile C band dual Doppler facility

In this paper the authors describe a System of two Doppler radars (the RONSARD System) operated for the study of precipitating clouds (fronts and convective storms). In a first part, emphasis is placed on the System requirements concerning both transportability and flexibility, due to the wide range of atmosphere phenomena to be observed. These requirements lead to an original implementation of the aerial, to a special design of the receiving chain (dual polarization capability, wide dynamic range, absolute self calibration capability) and to the implementation of real time digital subsystems (Amplitude and Phase Memory, Ground clutter cancellor, Fourier Transform processor, Ambiguous Velocity corrector and a Spectrum Moment Computer). The second part is devoted to a brief review of the scientific programs involving the RONSARD System and to the présentation of some preliminary results

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International audienc

Fabricating Fukushima Daiichi in-vessel and ex-vessel fuel debris simulants for the development and qualification of laser cutting technique

International audienceIn their roadmap towards the decommissioning of Fukushima Daiichi reactors, the Japanese authorities plan to start removing fuel debris by the end of 2021. To reach this objective, several RetD projects have been launched and subsidized by the Japanese government. In this framework, a French consortium (COMEX Nucleaire/ONET Technologies, CEA and IRSN) has been selected to implement RetD related to the laser cutting of Fukushima Daiichi fuel debris and related dust collection technology. Some of the key aspects of this project are to fabricate representative corium debris simulants, to test laser cutting technique on these simulants and to measure the aerosols and dusts that are released during the debris thermal cutting. This paper concentrates on the first issue.Two representative corium compositions have been selected in-vessel debris having the average of Fukushima Daiichi Unit 2 (1F2) lower head debris composition best estimates from the OECD Benchmark Study of the Accident at the Fukushima Daiichi Nuclear Power Station (BSAF); ex-vessel debris composition chosen from DOE calculations on Fukushima Daiichi Unit 1 (1F1) molten core concrete interaction in order to maximize the concrete content and bound the possible composition space.Fission Products expected 10 years after plant shutdown have also been taken into account. As it was not possible within the current project timeframe to perform debris cutting tests with (depleted) uranium oxide, it has been necessary to simulate uranium oxide and hafnium oxide has been considered as the best option.Based on its 20 year experience in corium experimental RetD, PLINIUS platform at CEA Cadarache has been chosen to fabricate these simulants. Two blocks of 8-10 kg have been induction melted. After melting and cooling, samples have been analyzed (microstructure and chemical composition) and laser cutting of these simulant blocks has been successfully carried out

Distinctive MRI features of paraneoplastic encephalitis with anti-Ri antibodies

International audienc