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International audience; The Upper Rhine Graben has two Plio-Quaternary depocentres usually interpreted as resulting from tectonic reactivation. The southern basin, near Freiburg im Breisgau (Germany), contains up to 250m of sediments. Beneath the younger alluvial deposits related to the current drainage system, a former river network deeply entrenched in the substratum reveals a very low regional base level of early Pleistocene age. The offset of channels at faults allows us to infer a Pleistocene reactivation of the syn-rift fault pattern and the estimation of slip rates. Maximum vertical movements along the faults have not exceeded 0.1 mm/yr since the middle Pleistocene. Current activity is concentrated along the westernmost faults. Morphologic markers indicate late Pleistocene reactivation of the Rhine River fault, and geophysical prospecting suggests a near-surface offset of young sedimentary deposits. The size of the fault segments potentially reactivated suggests that earthquakes with magnitude larger than Mw ¼ 6:3 could be expected in the area with a return interval of about 8000 years. Extrapolated to the duration of the Plio-Pleistocene, the strain rate estimates reveal that the tectonic forcing may account for only one-third to one-half of the whole thickness of the Plio-Pleistocene sediments of the basin fill. Thus other processes must be invoked to understand the growth of the Plio-Pleistocene basin. Especially the piracy of the Rhine River to the north during the early Pleistocene could explain these effects.

International audience; Fluorescence sensors mounted on unmanned underwater gliders open new ways of investigation to detect dissolved hydrocarbons in seawater. A glider was deployed for 20 days to monitor biogeochemical and physical signals associated with natural hydrocarbon seepages within the first 700 m in the Angolan waters. The glider was equipped with fluorometers (MiniFluo-UV) to measure the concentrations of polycyclic aromatic hydrocarbons (PAH) of interest, i.e. naphthalene, phenanthrene, fluorene and pyrene. A continuous PAH-like signal detected within the 70 m layer below the sea surface is associated with high chlorophyll concentration in the deep chlorophyll maximum. Vertical PAH-like anomalies forming either strong spikes or diffuse columns down to 700 m are observed at the exact location of oil seep sites identified on Synthetic Aperture Radar satellite images. An ~200 m thick layer of enhanced PAH-like concentration, topped by a thermo/pycnocline identified at 280–300 m water depth, is measured in concomitance with the decrease in oxygen concentration. The concomitance of these signals suggests that lower oxygen concentrations induce a preservation of hydrocarbons within the eastern Atlantic oxygen minimum zone. Even if the absence of in-situ measurements limits the understanding of physical and biogeochemical processes affecting PAH concentrations, the measurements conducted at the edges of the OMZ suggests a relationship with microbial activity and organic matter dynamics in this layer. The results presented here show that gliders equipped with PAH sensors represent a promising means for monitoring hydrocarbons in the oceans, especially when they are coupled with other systems (i.e. Synthetic Aperture Radar).

International audience; This paper proposes a particular study of the classic internal model control algorithm for a sampled- data system in a generalized context of uncertainty. Besides the usually considered model mismatch, the particularity of the case under consideration is that the measurements available to the control algorithm suffer from large, varying and uncertain delays. The presented study considers a simple SISO nonlinear system. The control algorithm is a sampled nonlinear model-based controller with successive model inversion and bias correction. The main contribution of this article is its proof of global convergence and robustness despite time-varying delays and uncertain measurement dating. In particular, the model error, the varying delays and measurements dating error are treated using monotonicity of the system and a detailed analysis of the closed-loop behaviour of the sampled dynamics, in an appropriate norm.

This article reports the developments of the technology used at TOTAL for estimating, controlling and optimizing the quality of fuels produced in refineries. Some key difficulties and practical problems are discussed along with a schematic description of the developed solutions and on-going research efforts.

The occurrence, in large shelf edge deltas, of gravity driven deformation related to overpressured shales is now well documented in many natural examples. In this paper, we explored the implications of the migration of the delta front on the kinematics of gravity driven deformation, in a case where the stratigraphic framework is detailed enough to discuss deformation kinematics and sedimentary supply at high temporal resolution (×0.1 Myr). We determined the deformation for the last 4 Myr at the scale of the whole Eastern Niger Delta. The upslope extensional domain showed EW asymmetric grabens. The transitional domain displayed (i) deformation restricted to folding to the east and (ii) a thicker sedimentary wedge and a larger deformation accommodated by thrust related folds to the west. The compressional front was a fold and thrust belt. Extensional deformation decreased in amount and rate over the Plio-Pleistocene. It also evolved significantly from distributed over the whole area to localized either to the western or eastern domains over that period. The compressional deformation followed the same evolution (i.e. the greater the extension, the greater the compression in either time or space), demonstrating the strong coupling between the extensional and compressional domains. Gravity deformation during the Plio-Pleistocene was driven by the continental slope spanning the coastal plain to distal deposits over the oceanic crust (about 2800 m of gravity potential). The superimposition of the delta front migration area and the extensional domain show that the associated pressure gradient localized the extensional domain. Deformation was closely linked to migrations of the delta front and the sedimentary supply reaching the delta: (i) the decrease in extension rate over the Plio-Pleistocene is related to a decrease in sedimentary supply over the Plio-Pleistocene, and, (ii) the spatial variations in extension intensity and rate are related to spatial variations of sedimentary supply.

Ethylene/α-olefin copolymers having bimodal molar weight distribution are investigated in comparison with unimodal copolymers in order to understand the incidence of the molecular architecture on the stress cracking resistance. The preferred introduction of the co-units in the longest chains of bimodal copolymers is suggested to favour the occurrence of intercrystalline tie molecules during crystallisation. The more complex is the molecular architecture, the greater is the difficulty for crystallisation by regular chain folding. Intermolecular chemical heterogeneity resulting from preferred incorporation of the co-units in the long chains enhances the co-unit disturbing effect on crystallisation without reducing crystallinity. Intra-molecular heterogeneity of the co-unit distribution is also suggested to be an efficient means to generate tie molecules and random chain folding at the expense of regular chain folding. Isothermal crystallisation is used to probe the effect of molecular architecture on the crystallisation kinetics. It appeared that the correlations between kinetics, molecular architecture and molecular topology of unimodal copolymers no longer hold when considering bimodal copolymers. In contrast, the crystal surface free energy proved to be sensitive to topological changes resulting from molecular architecture modifications.