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Marrakesh, Morocco

Omari L.H.,British Petroleum | Sayouri S.,British Petroleum | Lamcharfi T.,FST | Hajji L.,Departement de Physique
Journal of Electroceramics | Year: 2015

Pb1−xLax(Fe0.03Ti0.97)O3 (PLxF3T), (x = 0.04, 0.05, 0.06, 0.07, 0.10, 0.12, 0.14, 0.18 and 0.21), ceramics were synthesized by sol-gel method. XRD patterns indicated that the ceramics have tetragonal structure which transforms to pseudo-cubic structure. MEB micrographs show fine and homogenous spherical nano-metric grains. Dielectric properties were investigated in the frequency range from 1 kHz to 1 MHz. The Curie temperature decreases with increasing La content into the lattice. The diffusivity and the relaxation strength were estimated using the modified Uchino-law. The relaxation time of these materials was well-adjusted by the Vogel-Fulcher equation. © 2014, Springer Science+Business Media New York. Source

Mekhfi M.,Departement de Physique
General Relativity and Gravitation | Year: 2013

Point-like masses on a given initial domain of the complex plane are interacting globally under gravity and as a consequence the initial domain is mapped into a final domain which encodes all effects of localized sources. The mapping between the two domains is a truncated beta function which so far has not been fully investigated. In this paper we propose to know more about the final domain and so we start from the remark that when the masses are put on the real axis of the upper half plane, the mapping in question is the Schwarz-Christoffel mapping (SCM), a popular and useful tool in computational geometry. The linking of planar gravity with the SCM will allow us to use all what we know from this mapping to get answer for certain static solutions in planar gravity. Among the problems we will study we mention: masses distributed on the real axis of the full complex plane, masses distributed on a circle, the dust string either closed or infinite open. Strings with tensions are however not linked to SCM as these mappings do not involve the concept of tension. © 2013 Springer Science+Business Media New York. Source

Tricha M.,British Petroleum | Gueraoui K.,Equipe de modelisation en mecanique des fluides et en environnement | Gueraoui K.,University of Ottawa | Zeggwagh G.,British Petroleum | Mzerd A.,Departement de Physique
International Review of Mechanical Engineering | Year: 2014

The mean objective of the present study is to establish a numerical code to simulate the blood flow considered as non Newtonian fluid through deformable tubes. Using an implicit finite volumes method to solve the local and integral equations systems and the equation of the tube, we determine the global and the local quantities for the flow. This study considered as a step in the modelling of flow in blood vessels, may also contribute to other important fields such as molten polymers flow. © 2014 Praise Worthy Prize S.r.l. - All rights reserved. Source

Kuhn A.,Kastler-Brossel Laboratory | Neuhaus L.,Kastler-Brossel Laboratory | Van Brackel E.,Departement de Physique | Chartier C.,ONERA | And 9 more authors.
AIP Conference Proceedings | Year: 2014

Demonstrating the quantum ground state of a macroscopic mechanical object is a major experimental challenge in physics, at the origin of the rapid emergence of cavity optomechanics. We have developed a new generation of optomechanical devices, based on a microgram quartz micropillar with a very high mechanical quality factor. The structure is used as end mirror in a Fabry-Perot cavity with a high optical finesse, leading to ultra-sensitive interferometric measurement of the resonator displacement. We expect to reach the ground state of this optomechanical resonator by combining cryogenic cooling in a dilution fridge at 30 mK and radiation-pressure cooling. We have already carried out a quantum-limited measurement of the micropillar thermal noise at low temperature. © 2014 AIP Publishing LLC. Source

Omari L.H.,University of Monastir | Sayouri S.,University of Monastir | Lamcherfi T.,FST | Hajji L.,Departement de Physique
Physical and Chemical News | Year: 2012

Pb 1-yLa y (Fe 0.01 Ti 0.99) (1-y/4) O 3, y=0; 3; 7; 12; 18 and 21%, ceramic powders have been successfully synthesised using the sol-gel process and they have been structurally characterized using X ray diffraction (XRD) and Scanning electron microscopy (SEM). The average grain size was estimated using Scherrer's formula, which is consistent with the analysis of SEM images. Dielectric measurements revealed the existence of interesting features due to the incorporation of Fe in PLT matrix. The results are compared with those of the literature and interpreted. Source

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