152 research outputs found

    La solidarité populaire abidjanaise en chiffres

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    Résidence, tenure foncière, alliance dans une société bilinéaire (Sérèr du Sine et du Baol, Sénégal)

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    M. Dupire, A. Lericollais, B. Delpech et J.-M. Gastellu — Residence, Land Tenure and Marriage in a Double-Descent Society: The Serer from the Sine and Baol Regions of Senegal. This society is characterized by virilocal residence, double-descent, and matrilineal inheritance of non-consumable goods. Residential compounds are inherited in both the agnatic and the uterine lines, the relative proportion of each type of succession varying in the four villages under study. A compound may be divided into 'wards', 'kitchens', and, further down, 'uterine huts', each of these units corresponding to a specifie economic function. Starting from K. Gough's five types of residential categories, we define seven different patterns, the form most frequently found being the patrilocal extended family, the elementary family and a composite type of avuncular family, in that order. There is a significant correlation between residence patterns and inheritance of traditional offices. 'Kitchens' differ from compounds insofar as they can be matrilocal and chiefly consist of elementary families. While married sons often live in the same 'kitchen' with their fathers, nephews seldom cohabit with their MB. The 'uterine hut' is the primary unit of economic accumulation. The bilineal pattern of inheritance is also found in the four-level System of land-rights, with a correlation between land-rights and residence. Residential patterns and pre-ferential marriages tend to counterbalance the dispersal of a matrilineage's women resulting from virilocality.Dupire Marguerite, Lericollais André, Delpech Bernard, Gastellu Jean-Marc. Résidence, tenure foncière, alliance dans une société bilinéaire (Serer du Sine et du Baol, Sénégal).. In: Cahiers d'études africaines, vol. 14, n°55, 1974. pp. 417-452

    Design and Tests of 500kW RF Windows for the ITER LHCD System

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    In the frame of a R\&D effort conducted by CEA toward the design and the qualification of a 5 GHz LHCD system for the ITER tokamak, two 5 GHz 500 kW/5 s windows have been designed, manufactured and tested at high power in collaboration with the National Fusion Research Institute (NFRI). The window design rely on a symmetrical pill-box concept with a cylindrical beryllium oxide ceramic brazed on an actively water cooled copper skirt. The ceramic RF properties have been measured on a test sample to get realistic values for guiding the design. Low power measurements of the manufactured windows show return losses below-32 dB and insertion losses between-0.01 dB and-0.05 dB, with an optimum frequency shifted toward lower frequencies. High power tests conducted at NFRI show unexpected total power loss for both windows. The ceramic temperature during RF pulses has been found to reach unexpected high temperature, preventing these windows to be used under CW conditions. A post-mortem RF analysis of samples taken from one window shows that the dielectric properties of the ceramic were not the ones measured on the manufacturer sample, which partly explain the differences with the reference modelling

    A new 3MW ECRH system at 105 GHz for WEST

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    The aim of the WEST experiments is to master long plasma pulses (1000s) and expose ITER-like tungsten wall to deposited heat fluxes up to 10 MW/m2^2. To increase the margin to reach the H-Mode and to control W-impurities in the plasma, the installation of an upgraded ECRH heating system, with a gyrotron performance of 1MW/1000s per unit, is planned in 2023. With the modifications of Tore Supra to WEST, simulations at a magnetic field B0_0∼3.7T and a central density ne0_{e0}∼6 × 1019^{19} m−3^{−3} show that the optimal frequency for central absorption is 105 GHz. For this purpose, a 105 GHz/1MW gyrotron (TH1511) has been designed at KIT in 2021, based on the technological design of the 140 GHz/1.5 MW (TH1507U) gyrotron for W7-X. Currently, three units are under fabrication at THALES. In the first phase of the project, some of the previous Tore Supra Electron Cyclotron (EC) system components will be re-installed and re-used whenever possible. This paper describes the studies performed to adapt the new ECRH system to 105 GHz and the status of the modifications necessary to re-start the system with a challenging schedule
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