A significant fraction of the global carbon flux to the ocean occurs in River-dominated Ocean Margins (RiOMar) although large uncertainties remain in the cycle of organic matter (OM) in these systems. In particular, the OM sources and residence time have not been well clarified. Surface (0-1 cm) and sub-surface (3-4 cm) sediments and water column particles (bottom and intermediate depth) from the Rhô ne River delta system were collected in June 2005 and in April 2007 for a multi-proxy study. Lignin phenols, black carbon (BC), proto-kerogen/BC mixture, polycyclic aromatic hydrocarbons (PAHs), carbon stable isotope (d 13 C OC ), and radiocarbon measurements (D 14 C OC ) were carried out to characterize the source of sedimentary organic material and to address degradation and transport processes. The bulk OM in the prodelta sediment appears to have a predominantly modern terrigenous origin with a significant contribution of modern vascular C 3 plant detritus (D 14 C OC = 27.9&, d 13 C OC = À27.4&). In contrast, the adjacent continental shelf, below the river plume, seems to be dominated by aged OM (D 14 C OC = À400&, d 13 C OC = À24.2&), and shows no evidence of dilution and/or replacement by freshly produced marine carbon. Our data suggest an important contribution of black carbon (50% of OC) in the continental shelf sediments. Selective degradation processes occur along the main dispersal sediment system, promoting the loss of a modern terrestrial OM but also proto-kerogen-like OM. In addition, we hypothesize that during the transport across the shelf, a long term resuspension/deposition loop induces efficient long term degradation processes able to rework such refractory-like material until the OC is protected by the mineral matrix of particles.

The present paper aims at applying the Finite Element Updating inverse method to several sample geometries by the means of Digital Image Correlation. The full-field data are experimentally obtained from three geometries exhibiting increasing strain fields heterogeneities. For each test, a Finite Element model is built and boundary conditions are duplicated from the measured displacements at the sample borders. Field comparisons are performed at several time steps until fracture occurs and a Levenberg-Marquardt method is used to solve the optimization problem. Six parameters of an anisotropic elastic-plastic constitutive model are identified and validated through the simulation of a deep-drawing forming operation. Results show that identification quality is improved when heterogeneous strain fields are used.

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International audienceThe presently active region of the Congo deep-sea fan (around 330 000 km2), called the terminal lobes or lobe complex, covers an area of 2500 km2 at 4700–5100 m water depth and 750–800 km offshore. It is a unique sedimentary area in the world ocean fed by a submarine canyon and a channel-levee system which presently deliver large amounts of organic carbon originating from the Congo River by turbidity currents. This particularity is due to the deep incision of the shelf by the Congo canyon, up to 30 km into the estuary, which funnels the Congo River sediments into the deep-sea. The connection between the river and the canyon is unique for major world rivers

In the powder shaping process, friction is often considered as one of the main limiting factors since it can be the cause of bad green density distributions as well as ejection defects. Therefore, knowledge of this is important for better controlling the compaction stage. This paper makes an attempt to bring out the different process parameters (density, normal stress, sliding velocity, temperature, and displacement) which influence the friction between a standard iron powder and a tool in tungsten carbide. With this view, a sliding piece device has been built and is described. Several tests have been performed; from the results emerge a decrease of the friction coefficient with increasing density or normal stress, conversely the velocity increases the friction while temperature has PM75554.10.1 no significant role. In this work, particular attention 1 Sliding piece device: 1=optical transducer, 2= is given to the amplitude of the displacement showing transducer, 3=disc, 4=parallelipipedic slab, 5=force that it can highly affect friction and wear of green transducer, 6=hydraulic press, 7=cylindrical die, 8= parts. An attempt is made at explaining the observed press phenomena and results are correlated with an analytical expression. PM/0952 the process parameters on friction. Using an iron powder, authors4,9 have observed that the friction coefficient Dr Doremus and Dr Toussaint are at Institut decreased when increasing normal stress while Mallender National Polytechnique de Grenoble, Laboratoire et al. are the only authors who have measured an increase Sols Solides Structures, Domaine Universitaire, of this coefficient with density. The second type of BP 53, 38041 Grenoble cedex 9, France and Dr Pavier equipment allows one to study the role of the different is with Ferroxdure, Aimants permanents, 41, rue parameters independently, such as the density of the Pierre Brossollette,