Loïc Trégourès, Le football dans le chaos yougoslave

Longtemps objet de fascination empreint de romantisme, le football yougoslave, sublimé par ses « Brésiliens de l’Europe », interpelle la science politique comme en témoigne l’ouvrage de Loïc Trégourès, version remaniée et abrégée de sa thèse de doctorat. Ce travail comble une lacune dans la littérature francophone et rejoint celui de l’historien britannique Richard Mills, l’un des rares chercheurs occidentaux à s’intéresser au sujet depuis une dizaine d’années. La démarche du politologue, déj..

Centrifugal casting of ZA8 zinc alloy and composite A356/SiC : study and modeling of phases' and particles' segragation

Centrifugation is a casting technology that allows the production of cylindrical and graduated parts with different mechanical properties through the section. The need for materials with good quality and specific mechanical properties has been driven this technology in order to produce different types of materials such as zinc alloys and graduated metal matrix composites reinforced by hard and wear resistant particles. The goal of this research project is to study and model the eutectic macrosegregation, the solidification speed, and the speeds of solidification fronts during centrifugal casting of ZA8 zinc-aluminum alloy in order to improve the part quality and increase its strength and field reliability. Moreover, the segregation of the particles during centrifugal casting of an aluminum matrix composite reinforced by silicon carbide particles (A356/SiC) is also studied to improve and control the graduation of the parts. The cooling rate, the speed, acceleration/deceleration, displacement, and segregation of the particles across the section will be modeled by discretization of Stokes’ law in time in order to take into consideration the change in the centrifugal radius and melt viscosity during cooling process. This study will allow the control of the graduation degree of particles across the section in order to improve the properties and wear resistance of the composite. This composite can be used in systems where friction is critical and load is high (reinforcements of parts for the cylinders of pneumatic systems). The results show that the maximum macrosegregation zone of the eutectic across the casting section corresponds to the last point of solidification. The eutectic macrosegregation produced during centrifugal casting of thin walled part is a normal segregation which varies depending on the solidification speed and the ratio between the speeds of solidification fronts. On the other hand, it was found that the position and volume fraction of the particles on the outer/inner casting surface and across the section varies whether the viscosity of the liquid metal used and the centrifugal radius are considered constant or variable during the modeling. Modeling the particles’ segregation while discretizing, in time, the particles’ velocities gives more consistent results compared to those obtained experimentally

Usinage à sec des alliages légers et des composites

Les alliages légers tels que l'aluminium, le magnésium et les composites à matrice d'aluminium renforcés par des particules (CMMp) sont de plus en plus utilisés dans l'industrie. Pour fabriquer des pièces l'usinage est nécessaire surtout après la mise en forme par fonderie. D'autre part, les contraintes environnementales sont de plus en plus pressantes et tendent à imposer l'usinage à sec. Il existe très peu de données sur les poussières générées lors de l'usinage et sur l'usinage à sec. Dans ce travail on a précisé les conditions d'usinage par perçage. On a aussi comparé l'usinabilité des alliages du magnésium et des composites à matrice métallique (CMMp) avec celui de l'aluminium. Nous avons ainsi précisé l'influence du type de particules de renfort sur l'usinabilité de CMMp et étudié le mécanisme de formation des copeaux. Enfin on a précisé les mécanismes et les conditions de coupe qui influencent la quantité des poussières produites

Recent progress in magnesium-based thermoelectric materials

Magnesium-based thermoelectric materials (Mg2X, X = Si, Ge, Sn) are considered one of the most attractive groups for large-scale application, due to their materials’ high availability, low cost, low mass density and reasonably high efficiency. In this work, we present an overview of the recent developments relating to magnesium-based thermoelectric materials and review the current approaches towards high thermoelectric efficiency

Shape Variation in Aterian Tanged Tools and the Origins of Projectile Technology: A Morphometric Perspective on Stone Tool Function

BACKGROUND: Recent findings suggest that the North African Middle Stone Age technocomplex known as the Aterian is both much older than previously assumed, and certainly associated with fossils exhibiting anatomically modern human morphology and behavior. The Aterian is defined by the presence of 'tanged' or 'stemmed' tools, which have been widely assumed to be among the earliest projectile weapon tips. The present study systematically investigates morphological variation in a large sample of Aterian tools to test the hypothesis that these tools were hafted and/or used as projectile weapons. METHODOLOGY/PRINCIPAL FINDINGS: Both classical morphometrics and Elliptical Fourier Analysis of tool outlines are used to show that the shape variation in the sample exhibits size-dependent patterns consistent with a reduction of the tools from the tip down, with the tang remaining intact. Additionally, the process of reduction led to increasing side-to-side asymmetries as the tools got smaller. Finally, a comparison of shape-change trajectories between Aterian tools and Late Paleolithic arrowheads from the North German site of Stellmoor reveal significant differences in terms of the amount and location of the variation. CONCLUSIONS/SIGNIFICANCE: The patterns of size-dependent shape variation strongly support the functional hypothesis of Aterian tools as hafted knives or scrapers with alternating active edges, rather than as weapon tips. Nevertheless, the same morphological patterns are interpreted as one of the earliest evidences for a hafting modification, and for the successful combination of different raw materials (haft and stone tip) into one implement, in itself an important achievement in the evolution of hominin technologies

L’Abbé Glory

Balout Lionel. L’Abbé Glory. In: Gallia préhistoire. Suppléments, supplément 12, 1979. Lascaux inconnu. pp. 11-14

La momie de Ramsès II au Musée de l'Homme

L'auteur décrit l'état de la momie de Ramsès II ainsi que les différents examens auxquels elle a été soumise, en France, en vue de sa restauration. Il s'agit, comme il est noté en conclusion, d'une extraordinaire opération scientifique multidisciplinaire comme l'archéologie n'en a peut-être jamais réalisée en France

L’Abbé Glory

Balout Lionel. L’Abbé Glory. In: Gallia préhistoire. Suppléments, supplément 12, 1979. Lascaux inconnu. pp. 11-14

La Pr\ue9histoire. Le\ue7on inaugurale de la Chaire de Pr\ue9histoire prononc\ue9e le 14 avril 1964

Volume: 37Start Page: 208End Page: 23

Chronologie absolue et préhistoire saharienne

Balout Lionel. Chronologie absolue et préhistoire saharienne. In: Revue de l'Occident musulman et de la Méditerranée, n°11, 1972. pp. 13-19