Center Energie

Québec, Canada

Center Energie

Québec, Canada
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Mahmoud K.A.,Qatar Environment and Energy Research Institute | Mahmoud K.A.,Center Energie | Zourob M.,Center Energie | Zourob M.,King Saud University
Analyst | Year: 2013

A new lignin modified hybrid microsphere, comprising poly(styrene-co- acrylic acid) core and magnetite (Fe3O4)/Au nanoparticle (NP) shell, was proposed here for the selective and highly sensitive detection and removal of 2,4,6-trinitrotoluene (TNT) explosives based on surface enhanced Raman scattering (SERS) and electrochemical detection methods. The presence of lignin and the highly packed layer of Fe3O4/AuNPs as a magnetic collector and metal enhancer for SERS signals allowed for the detection of TNT below 1 pM. This journal is © 2013 The Royal Society of Chemistry.

Mahmoud K.A.,Qatar Environment and Energy Research Institute | Mahmoud K.A.,Khalifa University | Abdel-Wahab A.,Texas A&M University at Qatar | Zourob M.,Center Energie | Zourob M.,Cranfield University
Water Science and Technology | Year: 2015

A new versatile electrochemical sensor based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin (L-MMS) modified glassy carbon electrode (GCE) was developed for the selective detection of trace trinitrotoluene (TNT) from aqueous media with high sensitivity. The fabricated magnetic microspheres were characterized by transmission electron microscopy (TEM), energydispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). L-MMS films were cast on the GCE surface to fabricate the TNT sensing electrode. The limit of detection (LOD) of TNT determined by the amperometric i-t curve reached 35 pM. The lignin film and well packed Fe3O4/AuNPs facilitated the pre-concentration of trace TNT on the electrode surface resulting in a fast amperometric response of 3 seconds near the detection limit. The high sensitivity and excellent catalytic activity of the modified electrode could be attributed to the lignin layer and highly packed Fe3O4/AuNPs on the electrode surface. The total recovery of TNT from tapwater and seawater matrices was 98% and 96%, respectively. The electrode film was highly stable after five repeated adsorption/desorption cycles. The new electrochemical sensing scheme provides a highly selective, sensitive and versatile assay for the in-situ detection of TNT in complex water media. © IWA Publishing 2015 Water Science & Technology.

Bentouaf A.,University of Hassiba Ben Bouali Chlef | Bentouaf A.,University Djilali Liabes | Hassan F.H.,Lebanese University | Reshak A.H.,University of West Bohemia | And 3 more authors.
Journal of Electronic Materials | Year: 2016

We report on the investigation of the structural and physical properties of the Co2VZ (Z = Al, Ga) Heusler alloys, with L21 structure, through first-principles calculations involving the full potential linearized augmented plane-wave method within density functional theory. These physical properties mainly revolve around the electronic, magnetic and thermodynamic properties. By using the Perdew–Burke–Ernzerhof generalized gradient approximation, the calculated lattice constants and spin magnetic moments were found to be in good agreement with the experimental data. Furthermore, the thermal effects using the quasi-harmonic Debye model have been investigated in depth while taking into account the lattice vibrations, the temperature and the pressure effects on the structural parameters. The heat capacities, the thermal expansion coefficient and the Debye temperatures have also been determined from the non-equilibrium Gibbs functions. An application of the atom in molecule theory is presented and discussed in order to analyze the bonding nature of the Heusler alloys. The focus is on the mixing of the metallic and covalent behavior of Co2VZ (Z = Al, Ga) Heusler alloys. © 2016 The Minerals, Metals & Materials Society

Daou I.,Equipe | Zegaoui O.,Equipe | El-Kaddadi L.,Equipe | Asbik M.,Equipe | Zari N.,Center Energie
Proceedings of 2016 International Renewable and Sustainable Energy Conference, IRSEC 2016 | Year: 2017

The use of organic polymers as shell to encapsulate the organic Phase Change Materials (PCMs) presents some disadvantages because of their being highly flammable, having a poor thermal stability and low thermal conductivity. The use of hybrid materials composed of organic and inorganic materials constitutes a promising way to improve chemical and thermal properties of microencapsulated PCMs (MEPCMs). In this research, organic-inorganic hybrid-MEPCMs were synthesized by utilizing paraffin as core and urea-formaldehyde (UF) polymer as shell, and ZnO metal oxide nanoparticles. The prepared samples were characterized using Fourier Transform Infrared spectroscopy, X-Ray Diffraction, Scanning Electron Microscopy, Differential Scanning Calorimetry and Thermogravimetric analysis. The obtained results showed that the synthesized hybrid-MEPCMs are in spherical and irregular forms and present a rougher surface due to the presence of metal oxide nanoparticles which are scattered onto the surface of microcapsules or wrapped by UF shell material. They also indicated the probable improvement of hybrid-MEPCMs' thermal stability. In this work, the influence of metal oxides content on structural, morphological and thermal properties of hybrid-MEPCMs is discussed. © 2016 IEEE.

Asbik M.,Moulay Ismaï University | Ansari O.,University Med uissi | Bah A.,University Med uissi | Zari N.,Center Energie | And 2 more authors.
Desalination | Year: 2016

The exergy analysis of a passive solar still combined with heat storage system is presented in meteorological conditions taken on 15th of June 2011 at Errachidia city (Latitude: 31°58'N, Longitude: 4°20'W, Morocco), to determine the magnitude of exergy losses during the heat storage/retrieve period. Paraffin wax is used as phase change material (PCM) to store/retrieve energy in the process of changing the aggregate state from solid to liquid. The exergy balance equation for each element of the desalination unit as well as for the PCM is formulated and numerically solved. The variations versus time of temperature within PCM, the exergy destruction of solar still and that of PCM medium, the pure water productivity and exergy efficiency are shown in the obtained results. Effects of the influencing parameters (the thickness of the PCM medium, the ambient air velocity and the brackish water depth) on the exergy destruction (entropy generation) are highlighted. Moreover, the latent heat storage increases the water productivity and reduces the exergy efficiency. © 2015 Elsevier B.V.

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