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Utilization of magnetically treated water has been investigated and applied in many countries such as Russia, Australia, Israel, China and Japan. Studies have shown that the magnetic field is used as a safe alternative to improve plant growth and development. Although the properties of magnetically treated water have received a great deal of interest in recent years, there are no studies conducted in Moroccan agricultural conditions. The present study aimed at gaining more insight on the effect of magnetically treated irrigation water (MTIW) in the northwest region of Morocco, on the yield of strawberry plants (Fragaria × ananassa Duch. cv. Camarosa) and its components. The experiments were conducted in situ, during two crop seasons (2011-2012 and 2013-2014). The results confirm that physical treatment of irrigation water by a static magnetic field improves the yield and quality of strawberry fruits. The percentages of increase in number of flowers, number of fruits, fruit yield and quality of export production per 100 plants were 27.4%, 30.9%, 34.8%, 24.3%, respectively, compared with normal irrigation water (average over both crop seasons). These results suggest that irrigation with MTIW improves the production as well as the quality of the strawberry fruit, thus water use efficiency was enhanced. Therefore, the MTIW can be considered as a promising technique for improvement but extensive research is still required.

Ce travail est consacré à l'analyse, par la simulation numérique, du comportement élastoplastique des métaux et du contact unilatéral avec frottement sec de Coulomb. Dans cet objectif nous présentons un algorithme de résolution du problème d'évolution élastoplastique en présence du contact unilatéral avec frottement sec de Coulomb. Cet algorithme consiste à déterminer une formulation incrémentale à partir des équations de comportement temporelles de l'élastoplasticité et celle du contact unilatéral avec frottement sec de Coulomb. Cette dernière est modélisée au moyen de la théorie du bipotentiel permettant d'établir une formulation variationnelle basée sur un seul principe de minimum. Pour pallier les difficultés mathématiques dues à la non-différentiabilité des lois de contact et de frottement, deux algorithmes sont utilisés : la pénalisation et le Lagrangien augmenté avec l'algorithme de projection d'Uzawa.ABSTRACT. This work is devoted to the analysis, by numerical simulation, of the elastoplastic behaviour of metals and the unilateral contact with Coulomb's dry friction. With this objective, we present a solution algorithm for elastoplastic evolution, taking into account the unilateral contact with Coulomb's dry friction. This algorithm consists in an incremental formulation from temporal elastoplastic and unilateral contact laws. The latter is described by means of the bipotential theory. This allows us to use a variational formulation based on a minimum principle. To avoid the non-differentiability of the bipotential, two procedures are presented: the penalisation and the augmented Lagrangien method with the Uzawa's algorithm. MOTS-CLÉS : méthode des éléments finis, bipotentiel, frottement, régularisation, Lagrangien augmenté.

A numerical model for predicting calculation of the non-linear performance of reinforced concrete structures subjected to seismic loading is needed to better simulate the behavior of reinforced concrete bearing shear walls dimensioned capacity terms with respect to seismic activity. A flexibility-based, finite element multicellular multilayer plate model and a model for the simulation of the hysteretic behavior of structures have been proposed. The results confirm the model capacity to correctly represent the hysteretic behavior of a reinforced concrete structure dimensioned capacity terms with respect to seismic activity and envisage a deepening of this tool.

In order to improve the spherical thin shells’ vibrations analysis, we introduce a new analytical method. In this method, we take into consideration the terms of the inertial couples in the stress couples’ differential equations of motion. These inertial couples are omitted in the theories provided by Naghdi–Kalnins and Kunieda. The results show that the current method can solve the axisymmetric vibrations’ equations of elastic thin spherical shells. In this paper, we focus on verifying the current method, particularly for free vibrations with free edge and clamped edge boundary conditions. To check the validity and accuracy of the current analytical method, the natural frequencies determined by this method are compared with those available in the literature and those obtained by a finite element calculation.