100 research outputs found
Setting-up rules to characterize microsegregation
No full textCharacterization of chemical heterogeneities such as microsegregation resulting from solidification of metallic alloys is most often performed by EDS or WDS microanalysis with spot measurements located at corners of a regular grid. Rather than attempting a theoretical treatment of the statistics of such analyses, the quality of the procedure has been investigated by implementing “measurement” grids on numerical images that mimic solidification structures. Microstructures either with no geometrical constraints (uniform distribution of the solid nuclei) or with limited constraints that give some periodicity have been investigated. Systematic analysis of the effect of the location and size of the “measurement” grid enlightens the procedures which should be followed to minimize bias
3D-Representations for studying deep-sea coral habitats in the Lacaze-Duthiers Canyon, from geological settings to individual specimens
No full textInternational audienceThe Lacaze-Duthiers Canyon is located in the western Mediterranean Sea and is long known for hosting cold-water coral colonies in the canyon head region at depths ranging from 250 to 550 m. In 2019 during the CALADU cruise, three kinds of 3D-reconstructions were applied to better understand the distribution of coral colonies, their habitat and their skeleton morphologies. The canyon's flanks were mapped using a hull-mounted echosounder and an ROV multibeam echosounder. Digital terrain models were built with resolutions of 5 and 1 m and examined in three dimensions. ROV bathymetric data collected on the canyon's flanks made it possible to highlight a series of sub-parallel structures identified as lithified sedimentary strata along which coral colonies grow. Coral assemblages were explored at four locations and photographic images were assembled using structure from motion techniques to build photogrammetric models. Coral assemblages reconstructed in 3D enabled geo-localizing and recreating coral colonies on 16 models over a total area of 4370 m2. Two colonial species, Madrepora oculata and Desmophyllum pertusum were plotted and reported on bathymetric models to interpret their location at the scale of the canyon. The coordinates and depth of the colonies were used to calculate the vertical distribution (limited to our small bathymetric exploration, between 339 and 214 m depth) and density of populations (up to 4.3 colonies per m2). The spatial coverage of the 16 assemblages measured between 100 and 600 m2 each. The sizes of the colonies were measured to analyze the population structures of both species (mean sizes of 28 cm for D. pertusum and 18 cm for M. oculata, maximum sizes 1 m and 0.5 m, respectively, bushes 2.5 m long). In addition, lost fishing gears were quantified, longlines measured and their densities calculated (0.16 m/m2, up to 0.30 m/m2). An area with exuberant orange colonies of D. pertusum was discovered for the first time in the Lacaze-Duthiers Canyon. Five deep-sea scleractinian species were collected and micro-tomographic scans computed to view their intrinsic skeleton organization. Micro-CT scans of M. oculata, D. pertusum, Desmophyllum dianthus, Caryophyllia smithii, and Dendrophyllia cornigera enabled longitudinal and transversal cuts, highlighting morphological criteria for species identification and the multidirectional examination of specimens. We observed a thin canal connecting calices along the axis of D. pertusum colonies, and separate calices along the axis of M. oculata colonies
Relation between composition, microstructure and oxidation in iron aluminides
No full textThe relation between chemical composition, microstructure and oxidation properties has been investigated on various FeAl based alloys, the aim being to induce changes in the microstructure of the compound by selective oxidation of aluminium. Oxidation kinetics that was evaluated on bulk specimens showed that, due to fast diffusion in the alloys, no composition gradient is formed during the aluminium selective oxidation. Accordingly, significant aluminium depletion in the compound could be observed in the thinnest part of oxidised wedge-shape specimens. Another way to obtain samples of variable aluminium content was to prepare diffusion couples with one aluminide and pure iron as end members. These latter specimens have been characterised using electron microscopy and first results of oxidation experiments are presented
Suivi à 2 ans des patients insuffisants cardiaques implantés d un stimulateur de resynchronisation avec ou sans fonction de défibrillation (Observatoire CeRtiTuDe)
No full textPARIS7-Xavier Bichat (751182101) / SudocSudocFranceF
First principle energies of binary and ternary phases of the Fe–Nb–Ni–Cr system
No full textThis is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 5546 To cite this version: Connétable, Damien and Mathon, Muriel and Lacaze, Jacques First principle energies of binary and ternary phases of the Fe-Nb-Ni-Cr system. (2011) Calphad, vol. 35 (n° 4 a b s t r a c t We present first principles enthalpies of formation and lattice parameters of iron, nickel, chromium and niobium alloys. Some of these results have been partially used in a recent assessment of the Fe-Ni-Cr-Nb quaternary phase diagram. Emphasis has been put on the fcc (A1) and bcc (A2) unary structures, the X 3 Y-D0 22 , -L1 2 , -D0 3 , -D0 a , X 2 Y-C14(MgZn 2 ), -C15(MgCu 2 ) and -C36 (MgNi 2 ) Laves and X 7 Y 6 -D8 5 (µ) binary phases, and the X 8 Y 4 Z 18 -D8 b (σ ) ternary phase. We employed the state of the art to compute their properties by means of the DFT (PBE functional and PAW pseudo potentials). A comparison with experimental and theoretical data is also provided
Les apports des mesures Bâle II et Bâle III et leur impact sur la gestion du risque au sein des banques européennes
No full textAudit Financier et Opérationne
Alfred Foucher et l'Afghanistan, une archéologie militante dans les années 1920
No full text© Annick Fenet / Canal Académie - Tous droits réservésRadio broadcast of Canal Académie (http://www.canalacademie.com), in the "Amphi 23" program. The author is interviewed by the journalist Marianne Durand-Lacaze on her book "Documents d'archéologie militante. La mission Foucher en Afghanistan (1922-1925)" (Mémoires AIBL 42, 2010).Emission de la radio en ligne Canal Académie (http://www.canalacademie.com), dans la série "Amphi 23". L'auteur est interviewée par la journaliste Marianne Durand-Lacaze à propos de son ouvrage "Documents d'archéologie militante. La mission Foucher en Afghanistan (1922-1925)" (Mémoires AIBL 42, 2010)
Alfred Foucher et l'Afghanistan, une archéologie militante dans les années 1920
No full text© Annick Fenet / Canal Académie - Tous droits réservésRadio broadcast of Canal Académie (http://www.canalacademie.com), in the "Amphi 23" program. The author is interviewed by the journalist Marianne Durand-Lacaze on her book "Documents d'archéologie militante. La mission Foucher en Afghanistan (1922-1925)" (Mémoires AIBL 42, 2010).Emission de la radio en ligne Canal Académie (http://www.canalacademie.com), dans la série "Amphi 23". L'auteur est interviewée par la journaliste Marianne Durand-Lacaze à propos de son ouvrage "Documents d'archéologie militante. La mission Foucher en Afghanistan (1922-1925)" (Mémoires AIBL 42, 2010)
Alfred Foucher et l'Afghanistan, une archéologie militante dans les années 1920
No full text© Annick Fenet / Canal Académie - Tous droits réservésRadio broadcast of Canal Académie (http://www.canalacademie.com), in the "Amphi 23" program. The author is interviewed by the journalist Marianne Durand-Lacaze on her book "Documents d'archéologie militante. La mission Foucher en Afghanistan (1922-1925)" (Mémoires AIBL 42, 2010).Emission de la radio en ligne Canal Académie (http://www.canalacademie.com), dans la série "Amphi 23". L'auteur est interviewée par la journaliste Marianne Durand-Lacaze à propos de son ouvrage "Documents d'archéologie militante. La mission Foucher en Afghanistan (1922-1925)" (Mémoires AIBL 42, 2010)
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