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Migeon S.,French National Center for Scientific Research | Ducassou E.,University Bordeaux1 | Le Gonidec Y.,University Rennes1 | Rouillard P.,French National Center for Scientific Research | And 2 more authors.
Sedimentary Geology | Year: 2010

Based on an unusual data set comprises bathymetric data, backscatter imagery, seismic-reflection and Chirp profiles, and sediment cores, the Late Quaternary lobe at the mouth of the youngest turbidite channel off the western Nile deep-sea fan was investigated. The large-scale construction of the lobe through time and space is mainly controlled by 1) a pre-existing topography inherited from the downslope movement of Messinian evaporites, and 2) the type and nature of gravity flows delivered to the basin floor. The margins of the lobe are defined by high-backscatter acoustic facies that contrasts strongly with the low-backscatter facies from the surrounding abyssal-plain deposits. Within the lobe, low-backscatter facies characterise the main channel-levee systems and lobate bodies immediately beyond the end of the channels. Cores reveal that the high-backscatter facies corresponds to a series of extensive but thin debris-flow deposits with a fingered margin. These debrites comprise a muddy-sand matrix and dispersed clasts with diameter of 5 to 10. cm. The lower backscatter facies at channel mouths corresponds to alternations of thin sandy turbidites and muddy hemipelagites. Extensive thin debris flows therefore traversed surprisingly low gradients to reach the distal fringes of the lobe complex but are never found in the lobate bodies just beyond the channel mouths. Although the Nile deep-sea fan is considered as a silt/mud-rich accumulation, sand-prone deposits exist within the lobe. This sand/mud segregation results either from the presence of channelized features in the lobe and/or from the hydrodynamic process of particle transport by debris flows and turbulent flows. © 2010 Elsevier B.V. Source


Brugal J.-P.,French National Center for Scientific Research | Boudadi-Maligne M.,University Bordeaux1
Quaternary International | Year: 2011

The Caninae are especially abundant in the Plio-Pleistocene record of Western Europe where several genera, species and subspecies have been recognized, with some still under discussion about taxonomical attribution. They have important ecological roles among carnivoran guilds throughout the Quaternary, and some are high-level competitors. Their appearance and dispersal can be considered as major bioevents during different phases of the Quaternary. They therefore are relevant biochronological markers which can be correlated with main European faunal turnovers, from the 'wolf-event' at the end of the Pliocene, followed by high taxonomic diversity in Early to Middle Pleistocene and specific lineage with high size variation during the Middle and Late Pleistocene. As for many other mammals with very wide distribution, Canids demonstrate a relative high morphological and body-size (clinal) variability which in one sense are often underestimates and lead to creation of taxa from a geographical base, especially in southwestern Europe, characterized by high regional peculiarities (e.g. peninsular condition). This paper proposes a preliminary analysis, mostly based on teeth morphometry, of the taxonomy of wolf- and coyote/jackal-sized canids from distinct examples in southwestern Europe: small canids of Early Pleistocene age, discussion of genus Cuon and analysis of the etruscus-mosbachensis-lupus lineage. The contribution of Canids as biochronological taxa are discussed. © 2011 Elsevier Ltd and INQUA. Source


Lataste J.F.,University Bordeaux1 | De Larrard T.,Ecole Normale Superieure de Cachan | Benboudjema F.,Ecole Normale Superieure de Cachan | Semenadisse J.,VINCI Construction France
European Journal of Environmental and Civil Engineering | Year: 2012

This article presents electrical resistivity measurement on concrete. The first part presents the study of a lighter protocol for measuring electrical resistivity, allowing investigations of a large number of specimens, without degradation of the quality of final results. The second part is based on measurements made on two concretes cast regularly during one year each, on two sites. Measurements done to assess the different variability sources distinguish variability linked to the measurement of those related to the material. The third part of the article compares the laboratory measurements to those made on site. Finally, all the results reflected the interests of the resistivity measurement because of low variability obtained, and consistency between results. © 2012 Taylor & Francis. Source


Mitrovic D.,University of Montenegro | Bojkovicb V.,University Bordeaux1 | Danilov V.G.,Moscow Technical University of Communications and Informatics
Mathematical Methods in the Applied Sciences | Year: 2010

Using the weak asymptotic method, we approximate a triangular system of conservation laws arising from the so-called generalized pressureless gas dynamics by a diagonal linear system. Then, we apply the usual method of characteristics to find approximate solution to the original system. As a consequence, we shall see how the delta shock wave naturally arises along the characteristics. Also, we propose a procedure that could be applied to more general systems of conservation laws. Copyright © 2009 John Wiley & Sons, Ltd. Source


Chaplain M.,University Bordeaux1 | Bouras F.,University 08 Mai 45 | Nafa Z.,University 08 Mai 45
WCTE 2014 - World Conference on Timber Engineering, Proceedings | Year: 2014

This paper deals with the study of the LVL behaviour (Laminated Veneer Lumber) under cyclic torsion loading. This study is part of an approach to better design the wooden structures under extreme wind or earthquakes. Torsion tests were carried out on rectangular specimen, end fixed with possibility of sliding head to prevent warping. Before each cyclic test, each specimen is tested under a monotonous rotation in the elastic area: torsion angle limited to 15 °. A reference cyclic stress level is defined as the ratio of the maximum moment applied to the maximum moment reached during the initial monotonous test. The signal of cyclic loading is triangular at various levels and amplitudes; the frequency is fixed at 1 Hz. The experimental results are used to study the influence of stress level and load magnitude on the damage and on the lifetime. A Model based on the damage theory is proposed. These cyclic torsion tests performed on LVL are also compared to experiments realized on glulam. Source

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