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Dubousset J.,Academie nationale de medecine | Charpak G.,Paris West University Nanterre La Defense | Skalli W.,Ecole Nationale Superieure des Arts et Metiers | Deguise J.,Laboratoire Of Recherche En Imagerie Orthopedique | Kalifa G.,Hopital St Vincent de Paul
Journal of Musculoskeletal Research | Year: 2010

Very precise combined work between multidisciplinary partners (radiation engineers in physics, engineers in biomechanics, medical radiologists and orthopedic pediatric surgeons) has led to the concept and development of a new low-dose radiation device named EOS. This device has three main advantages: (1) Thanks to the invention of Georges Charpak who designed gaseous detectors for X-rays, the reduction of dose necessary to obtain a good image of skeletal system was 8 to 10 times less for 2D imaging; compared to the dose necessary to obtain a 3D reconstruction from CT scan cuts, the reduction factor was 800 to 1000. (2) The accuracy of 3D reconstruction obtained is better than that of 3D reconstruction from CT scan cuts. (3) The patient in addition gets imaged in a standing functional position, thanks to the AP and lateral X-rays obtained from head to feet simultaneously. This is a big advantage compared to CT scans which are used only in lying position. From the simultaneous AP and lateral X-rays of the whole body obtained via the 3D bone external envelop technique, the biomechanics engineers obtain 3D reconstruction of every level of osteo-articular system, especially for spine, in standing position with an acceptable period of time for reconstruction. This (in spite of the evolution of standing MRI) allows more precise bone reconstruction in orthopedics, especially at the level of the entire skeleton, including the head, spine, pelvis, lower limbs, giving new consideration for physiology, physiopathology and therapeutics. © 2010 World Scientific Publishing Company.

Allouhi A.,Ecole Superieure de Technology de Fes | Kousksou T.,University of Pau and Pays de lAdour | Jamil A.,Ecole Superieure de Technology de Fes | El Rhafiki T.,Ecole Nationale Superieure des Arts et Metiers | And 2 more authors.
Renewable and Sustainable Energy Reviews | Year: 2015

In addition to their harmful impact on the environment, air-conditioning applications account for a significant percentage of total energy utilization; thinking about clean resources becomes a world priority. Solar cooling systems using either adsorption or absorption technologies show a great potential since they can use a permanent energy and operate with environmentally safe working pairs. This paper investigates the potential of solar air-conditioning systems in Morocco (enjoying different climates) through a comparative study between conventional and solar closed cycle processes based on economic and environmental indicators. Accordingly, annual simulations in 6 climatic zones were performed to estimate cooling loads for a typical Modern Moroccan House. The major finding of this work is that solar air-conditioning systems in hot climates must be an attractive alternative to mitigate CO2 emissions and increase energy savings. However, the high installation cost is a main obstacle facing their implementation. © 2015 Elsevier Ltd. All rights reserved.

Kousksou T.,University of Pau and Pays de lAdour | Bruel P.,French National Center for Scientific Research | Cherreau G.,University of Pau and Pays de lAdour | Leoussoff V.,University of Pau and Pays de lAdour | El Rhafiki T.,Ecole Nationale Superieure des Arts et Metiers
Solar Energy | Year: 2011

The present numerical study is concerned with the use of phase change materials (PCMs) in solar-based domestic hot water (DHW) systems. During the last decade, the majority of the studies related to that issue concluded that the recourse to PCMs-based storage units was quite promising in order to enhance the overall performances of solar-based DHW systems. One recently interesting published numerical study (Talmatsky and Kribus, 2008), suggested though that this beneficial impact is not guaranteed since the gains observed over the day period brought by the presence of PCMs to store the solar energy were compensated by the losses undergone by the storage tank during the night. The origin of this absence of any beneficial impact of the use of PCMs in a DHW system has to be clearly understood in order to reconcile studies which indicated apparently contradictory findings. In that framework, the goal of the present contribution is to analyze the conditions under which such an absence of advantage of the use of PCMs in a DHW system were obtained in order to propose some possibilities of improvement for demonstrating the interest in using PCMs in solar-based DHW systems. Thus, the mathematical model based on the one reported in Talmatsky and Kribus (2008) is considered. This model describes the heat storage tank with PCM, collector, pump, controller and auxiliary heater. Realistic environmental conditions and typical end-user requirements are imposed. © 2011 Elsevier Ltd.

Mouakkir L.,Hassan II University | Smaoui H.,Ecole Nationale Superieure des Arts et Metiers | Mordane S.,Hassan II University | Chagdali M.,Hassan II University
Physical and Chemical News | Year: 2010

This paper concerns the modelling of the wave-tidal currents interaction. The tidal currents are computed by three-dimensional model MECCA (Model for Estuarine and Coastal Circulation Assessment), while the fields of the wave variables are performed by the propagation wave model SWAN (Simulating Waves Nearshore). The wave-tidal currents coupling was achieved by a parameterization of the roughness at the bottom according to the variables of the wave. The site of application of this modelling is centred on the coastal zone of Casablanca-Mohammedia. The modelling undertaken in this work shows successfully, the effects of the superposition of a wave to tidal currents, namely: increase in shear stress at the bottom compared to tidal currents alone, increase in the intensity of turbulence and finally, the reduction of the velocity close to the bottom (related to the increase in friction close to the bottom).

Massat J.-P.,SNCF | Balmes E.,Ecole Nationale Superieure des Arts et Metiers | Bianchi J.-P.,SDTools
Civil-Comp Proceedings | Year: 2016

Fatigue cracks can induce fracture of the catenary contact wire and thus significant costs for the operator. Nowadays the wear criterion to replace the contact wire leads to a lifespan of over fifty years, and the catenary can be subject to a very high number of cycles so that the fatigue life must be taken into account. A full process to compute the multiaxial transient stress field in the contact wire has been developed. A fatigue criticality indicator to assess the risk of crack initiation was introduced. This elaborate indicator is used to validate a simplified fatigue indicator based on the uniaxial Euler-Bernoulli beam stresses that are much faster to compute. This indicator is then used to assess parameters influencing the risk of fatigue in the case of junction claws. © Civil-Comp Press, 2016.

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