152 research outputs found

    Contribution to the study of some aspects of pollination in six varieties of apricot in the region of M'sila (Algeria)

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    The present work consists in contributing to the study of pollination. Field observations and tests were carried out on six varieties of apricot in the region of M'sila, "Pavit", "Boulida" "Alarbi","Tounsi","Ben sarmouk" and "Louzi rouge". For natural self-pollination, the branches were covered to avoid cross-pollination, and the fruit set was determined. Controlled pollination was carried out using pollen and pollen from the other trees that bloom at about the same time. The fruit set rate was determined after counting the fruits in relation to the number of blooming flowers. The rate of fruit set varies from one variety to another. Alarbi with 62.5%, Louzi with 69.7%, Tounssi with 56.5%, Bulida with 50.7%, Ben Sermouk with 23.2% and Pavit with 45.8%. The bagging rate of the bagged branch obtained at the end of the physiological fall did not show any significant differences between the varieties and ranged between 77.50% for Alarbi and 41.22% for Pavit. The results show that the number of fruits after manual crossing is zero for all crops. All varieties tested are self-compatible and no cross-compatibility group has been guessed on the tested growths, from self-pollination and inter-pollination

    Etude comparative de differents modeles mathematiques pour la prediction des niveaux de pollution atmospherique

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    SIGLECNRS TD Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

    MEASUREMENT OF RESIDUAL STRESSES BY THE NEUTRON DIFFRACTION TECHNIQUE IN A WELDED JOINT

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    The welds are the site of high residual stresses, localized in the vicinity of the weld cracks. Their presence caused many type of damage modes as stress corrosion, fatigue, sudden failure and increasing the temperature of ductile-brittle transition. Residual stresses in restrained welds and weld repairs are very complex. The heat treatment affects the value and distribution of residual stresses in the specimen. This peak stress in all three samples occurred not at the toe, but in the middle of the weld bead, where the yield stress is higher. The transverse residual stresses of around half the maximum value of longitudinal stress have been observed. The use of the neutron diffraction (ND) technique for residual stress measurements is described. In addition, studies of macrostructure and hardness were conducted. The results of different tests conclude the influence of heat treatment on residual stresses in welds

    L’accès au marché européen est une problématique marginale pour l’Algérie

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    National audiencePour cet ancien enseignant de l'université de Béjaïa, la PAC ne pose pas problème pour un pays comme l'Algérie du point de vue de l'accès au marché européen, du moment que les exportations sont très limitées. Ce qui pose réellement problème, c'est que la PAC ne fait pas de référence spécifique à la coopération avec les pays du sud de la Méditerranée
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