Hicham JABRAOUI - Academia.edu (original) (raw)
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Papers by Hicham JABRAOUI
E3S web of conferences, Dec 31, 2022
Physical Chemistry Chemical Physics
We conducted an extensive investigation using density functional theory (DFT) calculations and Re... more We conducted an extensive investigation using density functional theory (DFT) calculations and ReaxFF molecular dynamics (MD) simulations to elucidate the mechanisms of desulfurization and denitrogenation on Cu(100) surfaces.
Physical Chemistry Chemical Physics
The correlation between the boson peak intensities, the structural and elastic properties of sili... more The correlation between the boson peak intensities, the structural and elastic properties of silicate glasses (ternary and binary systems) are discussed in addition to an anomalous behavior of lithium compared to the other alkali oxide modifiers.
In this paper, a threaded tapered pin tool was employed to fabricate a 2-pass friction stir welde... more In this paper, a threaded tapered pin tool was employed to fabricate a 2-pass friction stir welded (FSWed) joint. To investigate the effectiveness of nano-sized SiC particles on microstructural and mechanical properties of the joint, the experiment was repeated while SiC particles had been inserted along the joint line. In another joint, a square pin tool was employed in the second pass to evaluate the effectiveness of switching pin geometry between passes on the aforementioned properties. Microstructural features including grain size, second phase particles and reinforcement distribution were examined via optical and scanning electron microscopy (SEM) techniques. In addition to satisfactory connections between SiC particles and the matrix, the most homogenous particles distribution was observed in the specimen FSWed with both pin tools. This observation was further supported by atomic force microscopy (AFM) examination. Additionally, the foregoing joint demonstrated the maximum tensile strength which was synonymous with its smallest grain size. During tensile testing, SiC-free joint and SiC-containing ones fractured from stir zone (SZ) and base metal, respectively. Moreover, SiC-free joint showed necking phenomenon. SEM results showed that the SiC-containing specimens possessed ductile fracture morphologies. On the other hand, SiC-free specimen showed a quasi-cleavage fracture mode confirming its moderate percent elongation. In the meantime, SiC-containing specimens exhibited superior hardness level to SiC-free specimen.
HAL (Le Centre pour la Communication Scientifique Directe), Mar 27, 2018
International audienc
Physical Chemistry Chemical Physics, 2017
Thermodynamic and microscopic structural properties of two Bi-based liquid alloys, such as In-Bi ... more Thermodynamic and microscopic structural properties of two Bi-based liquid alloys, such as In-Bi at 900 K and Tl-Bi at 750 K have been studied employing the regular associated solution model. We have estimated the mole fractions of the complexes and the free monomers assuming the existence of complexes In Bi 2 in In-Bi melt and TlBi in Tl-Bi melt. The thermodynamic properties have been studied by computing the Gibbs free energy of mixing, enthalpy of mixing, entropy of mixing and activities of the monomers. The compositional contributions of the heat associated with the formation of complexes and the heat of mixing of the monomers to the net enthalpy change has also been studied. The structural properties of the liquid alloys have been studied by computing concentration fluctuation in the longwavelength limit, chemical short-range order parameter and the ratio of mutual to intrinsic diffusion coefficients. For both of the alloy systems, the theoretical as well as the experimental values of S 0 CC () are found to be lower than the corresponding ideal values over the whole composition range, indicating the hetero-coordinating nature of Bi-In and Bi-Tl alloy melts. All the interaction energy parameters are found to be negative and temperature dependent, and both the alloy systems are found to be weakly interacting.
2023 3rd International Conference on Innovative Research in Applied Science, Engineering and Technology (IRASET)
HAL (Le Centre pour la Communication Scientifique Directe), Mar 27, 2018
International audienc
Physical Chemistry Chemical Physics
The paper elucidates the main driving mechanisms at play during the early stage of the Ti/CuO the... more The paper elucidates the main driving mechanisms at play during the early stage of the Ti/CuO thermite reaction using reactive forcefields in the frame of molecular dynamics calculations.
Physical Review Materials
This paper reports on the mechanisms of CuO decomposition and its associated phase transformation... more This paper reports on the mechanisms of CuO decomposition and its associated phase transformation into Cu2O, as a fundamental step of thermite materials reaction, where CuO serves as the oxidizer. Frenkel pair defects in perfect bulk CuO show extremely high formation energy (>4 eV) indicating that its decomposition initiates at defects/interfaces/surfaces, the latter being sensitive to surface orientation. In contrast to a variety of CuO surfaces ((111), (110), (101 ̅)) exhibiting threefold coordinated oxygen atoms, results show that oxygen vacancy formation requires higher disordered surfaces, such as the CuO(001), on which the vacancy formation activation energy is reduced to 1.31 eV. This leads to the exothermic formation of a chemisorbed O-O peroxy-bridge complex at the surface (-1.25 eV adsorption), that thermodynamically moderates the backreaction (vacancy annihilation). Further desorption of molecular oxygen necessitates an activation of 1.53 eV, compatible with CuO decomposition observed experimentally at 600 K (~second process duration). As a driving mechanism of oxygen release upon decomposition, migrations of the vacancy close to the surface and towards the bulk are determined for a number of crystalline directions and surface orientations and
Les biocarburants issus de la transformation de la biomasse de deuxième génération (2G), devraien... more Les biocarburants issus de la transformation de la biomasse de deuxième génération (2G), devraient remplacer les carburants fossiles dans le secteur des transports. Cependant, ces biocarburants peuvent contenir de 0.5 à 7.0 pds. % de composés oxygénés résiduels, en particulier des molécules phénoliques qui pendant la combustion dans le moteur peuvent se transformer en benzène qui est fortement cancérigène. Dans ce contexte, le défi qui se présente est de développer un processus d'adsorption sélectif pour éliminer les composés oxygénés de type phénolique des carburants liquides. Pour la première étape de notre travail, nous avons utilisé des calculs DFT pour sélectionner un matériau poreux approprié dans la famille des faujasites échangées aux cations monovalents (cation = H+, Li+, Na+, Cs+, Ag+ et Cu+) afin de trouver une formulation zéolitique avec une très forte affinité pour le phénol en présence d'eau et de toluène (molécule modèle de biocarburant). Nous avons trouvé que...
ACS Applied Materials & Interfaces
Journal of Chemical Physics, Apr 7, 2022
Physical Chemistry Chemical Physics, 2022
By microscopy, spectroscopy, and modelling we show that extended topological defects are ubiquito... more By microscopy, spectroscopy, and modelling we show that extended topological defects are ubiquitous in oxygen functionalised graphene, whether from gas-phase or wet-chemical oxidation, and play a critical role in limiting its reduction and stiffness.
Les biocarburants issus de la transformation de la biomasse de deuxieme generation (2G), devraien... more Les biocarburants issus de la transformation de la biomasse de deuxieme generation (2G), devraient remplacer les carburants fossiles dans le secteur des transports. Cependant, ces biocarburants peuvent contenir de 0.5 a 7.0 pds. % de composes oxygenes residuels, en particulier des molecules phenoliques qui pendant la combustion dans le moteur peuvent se transformer en benzene qui est fortement cancerigene. Dans ce contexte, le defi qui se presente est de developper un processus d'adsorption selectif pour eliminer les composes oxygenes de type phenolique des carburants liquides. Pour la premiere etape de notre travail, nous avons utilise des calculs DFT pour selectionner un materiau poreux approprie dans la famille des faujasites echangees aux cations monovalents (cation = H+, Li+, Na+, Cs+, Ag+ et Cu+) afin de trouver une formulation zeolitique avec une tres forte affinite pour le phenol en presence d'eau et de toluene (molecule modele de biocarburant). Nous avons trouve que...
E3S web of conferences, Dec 31, 2022
Physical Chemistry Chemical Physics
We conducted an extensive investigation using density functional theory (DFT) calculations and Re... more We conducted an extensive investigation using density functional theory (DFT) calculations and ReaxFF molecular dynamics (MD) simulations to elucidate the mechanisms of desulfurization and denitrogenation on Cu(100) surfaces.
Physical Chemistry Chemical Physics
The correlation between the boson peak intensities, the structural and elastic properties of sili... more The correlation between the boson peak intensities, the structural and elastic properties of silicate glasses (ternary and binary systems) are discussed in addition to an anomalous behavior of lithium compared to the other alkali oxide modifiers.
In this paper, a threaded tapered pin tool was employed to fabricate a 2-pass friction stir welde... more In this paper, a threaded tapered pin tool was employed to fabricate a 2-pass friction stir welded (FSWed) joint. To investigate the effectiveness of nano-sized SiC particles on microstructural and mechanical properties of the joint, the experiment was repeated while SiC particles had been inserted along the joint line. In another joint, a square pin tool was employed in the second pass to evaluate the effectiveness of switching pin geometry between passes on the aforementioned properties. Microstructural features including grain size, second phase particles and reinforcement distribution were examined via optical and scanning electron microscopy (SEM) techniques. In addition to satisfactory connections between SiC particles and the matrix, the most homogenous particles distribution was observed in the specimen FSWed with both pin tools. This observation was further supported by atomic force microscopy (AFM) examination. Additionally, the foregoing joint demonstrated the maximum tensile strength which was synonymous with its smallest grain size. During tensile testing, SiC-free joint and SiC-containing ones fractured from stir zone (SZ) and base metal, respectively. Moreover, SiC-free joint showed necking phenomenon. SEM results showed that the SiC-containing specimens possessed ductile fracture morphologies. On the other hand, SiC-free specimen showed a quasi-cleavage fracture mode confirming its moderate percent elongation. In the meantime, SiC-containing specimens exhibited superior hardness level to SiC-free specimen.
HAL (Le Centre pour la Communication Scientifique Directe), Mar 27, 2018
International audienc
Physical Chemistry Chemical Physics, 2017
Thermodynamic and microscopic structural properties of two Bi-based liquid alloys, such as In-Bi ... more Thermodynamic and microscopic structural properties of two Bi-based liquid alloys, such as In-Bi at 900 K and Tl-Bi at 750 K have been studied employing the regular associated solution model. We have estimated the mole fractions of the complexes and the free monomers assuming the existence of complexes In Bi 2 in In-Bi melt and TlBi in Tl-Bi melt. The thermodynamic properties have been studied by computing the Gibbs free energy of mixing, enthalpy of mixing, entropy of mixing and activities of the monomers. The compositional contributions of the heat associated with the formation of complexes and the heat of mixing of the monomers to the net enthalpy change has also been studied. The structural properties of the liquid alloys have been studied by computing concentration fluctuation in the longwavelength limit, chemical short-range order parameter and the ratio of mutual to intrinsic diffusion coefficients. For both of the alloy systems, the theoretical as well as the experimental values of S 0 CC () are found to be lower than the corresponding ideal values over the whole composition range, indicating the hetero-coordinating nature of Bi-In and Bi-Tl alloy melts. All the interaction energy parameters are found to be negative and temperature dependent, and both the alloy systems are found to be weakly interacting.
2023 3rd International Conference on Innovative Research in Applied Science, Engineering and Technology (IRASET)
HAL (Le Centre pour la Communication Scientifique Directe), Mar 27, 2018
International audienc
Physical Chemistry Chemical Physics
The paper elucidates the main driving mechanisms at play during the early stage of the Ti/CuO the... more The paper elucidates the main driving mechanisms at play during the early stage of the Ti/CuO thermite reaction using reactive forcefields in the frame of molecular dynamics calculations.
Physical Review Materials
This paper reports on the mechanisms of CuO decomposition and its associated phase transformation... more This paper reports on the mechanisms of CuO decomposition and its associated phase transformation into Cu2O, as a fundamental step of thermite materials reaction, where CuO serves as the oxidizer. Frenkel pair defects in perfect bulk CuO show extremely high formation energy (>4 eV) indicating that its decomposition initiates at defects/interfaces/surfaces, the latter being sensitive to surface orientation. In contrast to a variety of CuO surfaces ((111), (110), (101 ̅)) exhibiting threefold coordinated oxygen atoms, results show that oxygen vacancy formation requires higher disordered surfaces, such as the CuO(001), on which the vacancy formation activation energy is reduced to 1.31 eV. This leads to the exothermic formation of a chemisorbed O-O peroxy-bridge complex at the surface (-1.25 eV adsorption), that thermodynamically moderates the backreaction (vacancy annihilation). Further desorption of molecular oxygen necessitates an activation of 1.53 eV, compatible with CuO decomposition observed experimentally at 600 K (~second process duration). As a driving mechanism of oxygen release upon decomposition, migrations of the vacancy close to the surface and towards the bulk are determined for a number of crystalline directions and surface orientations and
Les biocarburants issus de la transformation de la biomasse de deuxième génération (2G), devraien... more Les biocarburants issus de la transformation de la biomasse de deuxième génération (2G), devraient remplacer les carburants fossiles dans le secteur des transports. Cependant, ces biocarburants peuvent contenir de 0.5 à 7.0 pds. % de composés oxygénés résiduels, en particulier des molécules phénoliques qui pendant la combustion dans le moteur peuvent se transformer en benzène qui est fortement cancérigène. Dans ce contexte, le défi qui se présente est de développer un processus d'adsorption sélectif pour éliminer les composés oxygénés de type phénolique des carburants liquides. Pour la première étape de notre travail, nous avons utilisé des calculs DFT pour sélectionner un matériau poreux approprié dans la famille des faujasites échangées aux cations monovalents (cation = H+, Li+, Na+, Cs+, Ag+ et Cu+) afin de trouver une formulation zéolitique avec une très forte affinité pour le phénol en présence d'eau et de toluène (molécule modèle de biocarburant). Nous avons trouvé que...
ACS Applied Materials & Interfaces
Journal of Chemical Physics, Apr 7, 2022
Physical Chemistry Chemical Physics, 2022
By microscopy, spectroscopy, and modelling we show that extended topological defects are ubiquito... more By microscopy, spectroscopy, and modelling we show that extended topological defects are ubiquitous in oxygen functionalised graphene, whether from gas-phase or wet-chemical oxidation, and play a critical role in limiting its reduction and stiffness.
Les biocarburants issus de la transformation de la biomasse de deuxieme generation (2G), devraien... more Les biocarburants issus de la transformation de la biomasse de deuxieme generation (2G), devraient remplacer les carburants fossiles dans le secteur des transports. Cependant, ces biocarburants peuvent contenir de 0.5 a 7.0 pds. % de composes oxygenes residuels, en particulier des molecules phenoliques qui pendant la combustion dans le moteur peuvent se transformer en benzene qui est fortement cancerigene. Dans ce contexte, le defi qui se presente est de developper un processus d'adsorption selectif pour eliminer les composes oxygenes de type phenolique des carburants liquides. Pour la premiere etape de notre travail, nous avons utilise des calculs DFT pour selectionner un materiau poreux approprie dans la famille des faujasites echangees aux cations monovalents (cation = H+, Li+, Na+, Cs+, Ag+ et Cu+) afin de trouver une formulation zeolitique avec une tres forte affinite pour le phenol en presence d'eau et de toluene (molecule modele de biocarburant). Nous avons trouve que...