his paper presents a combined experimental and theoretical investigation and proposes a mechanical load modeling of a multidirectional layer CFRP drilling to avoid fibers delamination by a better choice of their orientations. A first step consists in working with unidirectional CFRP to correlate cutting mode (opening, shear and bending) with force level depending on the angular tool position. The discretisation of the cutting edge is employed to know the exact contribution of each elementary part of the edge, resulting in a complete drill operation modeling (tip penetration, full engagement and exit). A second step consists in using this unidirectional approach to model a multidirectional layer CFRP drilling. In this case, layers are cut simultaneously which induce brutal mechanical load variation. A summation method is used to estimate the force level depending on fiber arrangement. Optimal orientation combinations are underlined by this approach, in order to improve the CFRP design, by considering the manufacturing concerns.

The plain of El-Outaya is in arid zone in southern Algeria. The groundwater are characterized by an Important and variabilityin its salinity. This work is presented to improve knowledge on these waters by proceeding to their statistical andhydrochemical classifications. Method C.A.H (hierarchical ascending classification) takes of three tendencies based on theimportance of the mineralization. The salt rocks are responsible of this height salinity. Concerning the hydrochemicalsynthesis, the statistical information is confirmed. There is three dominant groups.