University Internationale Of Rabat

El Jadida, Morocco

University Internationale Of Rabat

El Jadida, Morocco
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Jannot Y.,CNRS Mechanical Energy, Theories, and Applications Laboratory | Degiovanni A.,University Internationale Of Rabat | Grigorova-Moutiers V.,Saint - Gobain | Godefroy J.,CNRS Mechanical Energy, Theories, and Applications Laboratory
Measurement Science and Technology | Year: 2017

Hot plate methods under steady state conditions are based on a 1D model to estimate the thermal conductivity, using measurements of the temperatures T 0 and T 1 of the two sides of the sample and of the heat flux crossing it. To be consistent with the hypothesis of the 1D heat flux, either a hot plate guarded apparatus is used, or the temperature is measured at the centre of the sample. On one hand the latter method can be used only if the ratio thickness/width of the sample is sufficiently low and on the other hand the guarded hot plate method requires large width samples (typical cross section of 0.6 × 0.6 m2). That is why both methods cannot be used for low width samples. The method presented in this paper is based on an optimal choice of the temperatures T 0 and T 1 compared to the ambient temperature T a, enabling the estimation of the thermal conductivity with a centered hot plate method, by applying the 1D heat flux model. It will be shown that these optimal values do not depend on the size or on the thermal conductivity of samples (in the range 0.015-0.2 W m-1 K-1), but only on T a. The experimental results obtained validate the method for several reference samples for values of the ratio thickness/width up to 0.3, thus enabling the measurement of the thermal conductivity of samples having a small cross-section, down to 0.045 × 0.045 m2. © 2016 IOP Publishing Ltd.

Couto N.,Royal University | Couto N.,University of Porto | Silva V.,Royal University | Silva V.,University of Porto | And 9 more authors.
Applied Thermal Engineering | Year: 2015

As the quantity of municipal solid waste (MSW) increases with economic growth, problems arise in regard to sustainable management solutions. Thermal treatment presents a valid option for reducing the amounts of post-recycling waste to be landfilled. Incineration technology, besides reducing the total volume of waste and making use of the chemical energy in MSW for power generation, has negative environmental impact from high emission of pollutants. Recent policy to tackle climate change and resources conservation stimulated the development of renewable energy and landfill diversion technology, thereby giving gasification technology development renewed importance. In this work a two-dimensional CFD model for MSW gasification was developed and an Eulerian-Eulerian approach was used to describe the transport of mass, momentum and energy for the solid and gas phases. This model is validated using experimental data from the literature. The numerical results obtained are in good agreement with the reported experimental results. © 2014 Elsevier Ltd. All rights reserved.

Essehli R.,Qatar Environment and Energy Research Institute | Belharouak I.,Qatar Environment and Energy Research Institute | Ben Yahia H.,Qatar Environment and Energy Research Institute | Chamoun R.,Qatar Environment and Energy Research Institute | And 5 more authors.
Dalton Transactions | Year: 2015

A new orthophosphate α-Na2Ni2Fe(PO4)3 was synthesized using a solid state reaction route, and its crystal structure was determined from powder X-ray diffraction data. The physical properties of α-Na2Ni2Fe(PO4)3 were studied by magnetic and electrochemical measurements and by Mössbauer and Raman spectroscopy. α-Na2Ni2Fe(PO4)3 crystallizes according to a stuffed α-CrPO4-type structure with the space group Imma and the cell parameters a = 10.42821(12), b = 13.19862(15), c = 6.47634(8) Å, and Z = 4. The structure consists of a 3D-framework of octahedra and tetrahedra sharing corners and/or edges with channels along [100] and [010], in which the sodium atoms are located. The 57Fe Mössbauer spectrum indicates that the Fe3+ cation is distributed over two crystallographic sites implying the presence of a Ni2+/Fe3+ statistical disorder. Magnetic susceptibility follows the Curie-Weiss behavior above 100 K with θ = -114.3 K indicating the occurrence of predominant antiferromagnetic interactions. Electrochemical tests indicate that during the first discharge to 1 V vs. Na+/Na in a sodium cell, one Na+ ion could be inserted into the α-Na2Ni2Fe(PO4)3 structure. This has led to the formation of a new phase Na3Ni2Fe(PO4)3 which was found to be promising as a positive electrode material for sodium batteries. When α-Na2Ni2Fe(PO4)3 is further discharged to 0.03 V, it delivers a capacity of 960 mA h g-1. This corresponds to the intercalation of more than seven sodium atoms per formula unit which is an indication of a conversion-type behaviour with the formation of metallic Fe and Ni. When cycled in the voltage range 0.03-3 V vs. Na+/Na, at 20 °C, under the current rates of 50, 100, 200, and 400 mA g-1, reversible capacities of 238, 196, 153, and 115 mA h g-1, were obtained, respectively. This journal is © The Royal Society of Chemistry 2015.

Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: SSH.2012.4.2-1 | Award Amount: 8.27M | Year: 2013

FRAME, a 4-year multidisciplinary project, represents a consortium of 19 internationally recognized and globally networked human rights institutes from across Europe and strategic regions around the world. Through FRAME, more than 100 leading researchers and practitioners - with a strong gender balance - aim to provide the necessary building blocks for a coherent EU human rights policy comprised of: (i) a sound knowledge base taking account of the factors, concepts, institutions and instruments underlying human rights protection; (ii) appraisal of the EUs full potential to contribute to global human rights governance through its relationship with multiple actors and its manifold policies; and (iii) a set of indicators, tools and policy proposals geared to strengthen human rights implementation in EU policy-making. Through 4 research clusters, FRAME offers creative solutions to enhance the coherence and effectiveness of EU human rights policy. Cluster 1: Factors examines the key factors facilitating or hindering human rights protection, the concepts of human rights, democracy and the rule of law and the human rights protection institutions and instruments at global, regional and national level. Cluster 2: Actors addresses the EUs human rights engagement with the UN, regional multilateral organizations, regional and strategic partnerships with third countries and non-state actors, as well as the relationship between EU institutions and the Member States. Cluster 3: Policies hones the fostering of human rights in EU policies on development and trade, human rights violations in conflicts, freedom, security and justice and external human rights and democratization action. Cluster 4: Tools develops indicators, tools and policy proposals, including policy benchmarking, to monitor and improve the effectiveness of EU human rights policy. FRAMEs vital impact on human rights research, education and policy innovation will continue beyond the projects lifetime.

Al Azri M.,Sultan Qaboos University | Elzain M.,Sultan Qaboos University | Bouziane K.,University Internationale Of Rabat | Cherif S.M.,University of Paris 13 | And 2 more authors.
Journal of Applied Physics | Year: 2013

The electronic and magnetic properties of 6H-SiC with Mn impurities have been calculated using generalized gradient approximation formalism. Various configurations of Mn sites and Si and C vacancies were considered. It was found that 6H-SiC doped with Mn atoms possess a moment for both types of substitution. The Mn atom at Si site possesses larger magnetic moment than Mn atom at C site. The energy levels appearing in the band gap due to vacancies and due to Mn impurities are determined and the calculated densities of states are used to analyze the different values of the magnetic moments for different types of substitution. A model that explains the magnetic moment at Mn site is proposed. © 2013 American Institute of Physics.

Degiovanni A.,CNRS Mechanical Energy, Theories, and Applications Laboratory | Degiovanni A.,University Internationale Of Rabat | Remy B.,CNRS Mechanical Energy, Theories, and Applications Laboratory
International Journal of Thermal Sciences | Year: 2016

This paper deals with the relevant model that can be proposed for modelling interface heat transfer between a fluid and a wall for thermal boundary conditions varying in space and time. Usually, for a constant and uniform heat transfer (unidirectional steady-state regime), the problem can be solved through the introduction of the notion of a h heat transfer coefficient. This quantity, which is uniform in space and constant in time, links heat flux to a temperature difference (between the wall temperature Tw and an equivalent fluid temperature Tf, where h and Tf both depend on the system geometry) in a linear way.The problem we consider in this work concerns the heat transfer between a dynamically developed steady-state fluid flow and a wall submitted to transient and non-uniform thermal excitations, for instance a steady-state flow over a flat plate submitted to a pulsed and space-reduced heat flux, or a steady-state flow in a duct stimulated by a periodic flux on its outer surface. More generally, we assume that this kind of thermal problem can be described by:one or several linear partial differential equations with their associated linear boundary and interface conditions;the coefficients of the homogeneous part of these equations do not depend neither on time nor on the coordinates in the direction parallel to the fluid/solid interface (they may depend on the coordinate in the normal direction);volume and surface sources (non-homogeneous part of the previous equations) that can depend on space and/or time. We will show that the relevant representation for describing the interfacial heat transfer does not consist in defining a non-uniform and variable heat transfer coefficient h(x,t), as done usually: the corresponding relationship is not really intrinsic because it depends on the thermal boundary conditions. An alternative approach is proposed here. It relies on the introduction of a generalized impedance Z(ω,p), which is a double integral transform of a transfer function z(x,t) in the original space (x)/time (t) domain. This impedance function links heat flux and temperature difference through a convolution product (noted "⊗" here) rather than through a scalar product:Tw(x,t)-Tf(x,t)=z(x,t)⊗φ(x,t)After a presentation of the generic problem, simple cases, with analytical solutions, will be presented for validation, such as a plug flow, in steady-state and transient regimes. To conclude and show the interest of our approach, a comparison between a global approach and a numerical simulation in a more complex and less academic case will be presented. © 2015 Elsevier Masson SAS. All rights reserved.

Aljarrah M.,Zarqa University | Essadiqi E.,University Internationale Of Rabat
International Review of Mechanical Engineering | Year: 2012

The effect of alloying elements (Ca and Ca+Ce) on the solidification microstructure of AZ31 alloy has been investigated using optical microscopy and thermodynamic calculations. The effect of cooling rate on grain size of the studied alloys, in the as-cast, as-hot and postannealing conditions, were examined. Degassing of AZ31 alloy using (C 2Cl 6) tablet releases carbon which reacts with aluminum in the molten metal and forms high stable aluminum carbide phase (Al 4C 3). The precipitation of Al 4C 3 particles act as nuclei and refine the microstructure. It has been found that alloying AZ31 with Ca and Ca+Ce shows promising potentials in grain refinement by precipitating stable compounds. Secondary dendrite arm spacing (SDAS) and grain size of the ascast AZ31alloys were investigated with respect to cooling rate and, Ca and Ca+Ce additions. Experimental relationship between cooling rate and SDAS has been established. © 2012 Praise Worthy Prize S.r.l. - All rights reserved.

Willinger M.,Institut Universitaire de France | Ammar N.,Laval University | Ennasri A.,University Internationale Of Rabat
Environmental and Resource Economics | Year: 2014

The ambient tax is often considered as an efficient instrument to achieve a first best outcome of ambient pollution when the regulator cannot observe individual emissions, or when monitoring costs are prohibitive. While this view is supported to a large extent by experimental findings, there remains several hurdles that hinder the implementation of the ambient tax in the field. One of these hurdles is the nature of the damage. Experimental findings suggest that the efficiency of the ambient tax is higher under external damage, i.e. if ambient pollution affects non-polluters (Spraggon in J Public Econ 84:427–456, 2002) than under internal damage, i.e. if ambient pollution affects polluters themselves (Cochard et al. in Environ Resour Econ 30:393–422, 2005). But this result rests on very different experimental settings. Therefore, we designed a new experiment that allows to compare external and internal damage within a common setting. Our main finding is that the ambient tax is equally efficient under internal and external damage. © 2013, Springer Science+Business Media Dordrecht.

Aydin H.,McGill University | Essadiqi E.,University Internationale Of Rabat | Jung I.-H.,McGill University | Yue S.,McGill University
Materials Science and Engineering A | Year: 2013

In this paper, four different steel compositions, centered on Mn as the main alloying element, are designated as candidates for Third Generation AHSS grades. The design of these steels is based on controlling the deformation behavior of the retained austenite. Thus, heat treatment process parameters are determined in order to obtain different amounts and morphologies of retained austenite. The evolution of the microstructure, during processing as well as deformation, is characterized by using optical, electron microscopy techniques and mechanical tests. The effect of alloy composition and processing parameters on the deformation mechanisms of these steels is discussed. © 2012 Elsevier B.V.

Aydin H.,McGill University | Jung I.-H.,McGill University | Essadiqi E.,University Internationale Of Rabat | Yue S.,McGill University
Materials Science and Engineering A | Year: 2014

In the present work, a medium Mn, Fe-Mn-C-Al-Si alloy was subjected to different heat treatment conditions and subsequent deformation to understand the effect of these processes on austenite. It was found that, after intercritical annealing, the microstructure was ferrite plus austenite duplex phase (FADP) regardless of cooling rate to room temperature. When cold rolled, the retained austenite of the FADP structures exhibited both twinning and strain induced transformation (SIT) to martensite. A detailed characterization of the co-existence of twinning and SITing after cold rolling is presented. © 2013 Elsevier B.V.

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