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Item Carbon Nanotube Catalytic Deposition Synthesis(IEEE Journal, 2007) O. Guellati, A. Fonseca, W. Bounour, M. Guerioune, Z. Mekhalif, Joseph Delhalle, A. Benaldjia and Jànos B. NagyCarbon nanotubes "CNTs" have been the focus of numerous investigations because of their unique and superior properties that are a consequence of their particular structure. Their synthesis has been receiving much attention for a wide variety of applications. Though, scientists are researching more economic ways to produce these structures with high quality and purity, our aim in this research is to investigate and optimize the results of the CNTs growth process using CCVD technique. Due to its simplicity and low cost, this technique is perfectly suited for the production of nanomaterials for future industrial applications. MWNTs CCVD synthesis was carried out at 700degC in 5 to 120 minutes reaction. It is essentially based on 2 steps process: a catalyst impregnation preparation step followed by CCVD procedure using ethylene decomposition over Fe-Co/MgO support. During this synthesis, impurities were also produced. Thus, subsequent chemical purification steps were required to separate the tubes. Finally, characterization of crude and purified products was performed by TEM, SEM and FESEM focusing on composition, form and purity obtained.Item Reliability Analysis of Low Alloy Ferritic Piping Materials(Springer, Dordrecht, 2009) A. Guedri; B. Merzoug; Moe Khaleel; A. ZeghloulThe aim of this study is to improving microstructure and mechanical properties of the weldable gas pipeline steel using laboratory mill. To achieve the required microstructure and mechanical properties of thermo mechanically processed HSLA steels, it is necessary to have an idea about the role of composition and process parameters. The large numbers of parameters obtained during the production process in the plant were systematically changed to optimize the strength and toughness properties. The optimized parameters were used for the production of the API X60/X70 steel. However, the controlled cooling after rolling should result in transformed products that provide excellent combination of strength and toughness. The coiling at an appropriate temperature have the advantage of the precipitation strengthening, giving further rise to the high yield strength and also improvement in toughness of the steel. The coiling temperature is a decisive parameter because it determines the beginning of the formation of fine precipitations. Therefore, four different laboratory cooling systems were used, in this study to simulate the rolling conditions of a real industrial Thermomechanically controlled process, as close as possible and to check the possibilities of improving the mechanical properties of the welded pipeline steel.Item Gas Flow and Temperature Synthesis Dependence on the CNTs structure and yield(International Journal of Nanoelectronics and Materials, 2010) O. Guellati, S. Detriche, M. Guerioune, Z. Mekhalif and J. DelhalleItem Item Molecular modeling investigation of para-nitrobenzoic acid interaction in β-cyclodextrin(2011) Leila Nouar; Sakina Haiahem; Abdelazize Bouhadiba; Fatiha Madi; Leila LagrateGeometry optimizations of para-nitrobenzoic acid (PNBA)/β-cyclodextrin complex were carried out using MM+, PM3 and density function theory B3LYP/6-31G*. Calculations were performed upon the inclusion complexation of β-cyclodextrin (CD) with neutral (PNBA1) and anionic (PNBA2) species of para-nitrobenzoic acid. The results obtained from both methods consistently indicate that the complex of PNBA2/β-CD (B) is significantly more favorable than the others energetically. The negative enthalpy changes calculated from the statistical thermodynamic calculation suggest that both the inclusion complexation is favored enthalpy-driven process. The geometry of the most stable complex shows that the aromatic ring is deeply self-included inside the hydrophobic cavity of β-CD and also intermolecular hydrogen bonds were established between host and guest molecules. This suggests that hydrophobic effect and hydrogen bond play an important role in the complexation process.Item Theoretical study of inclusion complexation of 3-amino-5-nitrobenzisothiazole with β-cyclodextrin(2011) Leila Nouar; Sakina Haiahem; Abdelaziz Bouhadiba; Fatiha MadiThe inclusion process involving β-cyclodextrin (β-CD) and 3-amino-5-nitrobenzisothiazole (ANBT) has been investigated by using the MM+ force field, AM1, PM3, HF and B3LYP theories. In this study we took into account only the stochiometry1:1. The complexation and interaction energies for both orientations considered in this research are reported. All quantum computational methods gave the A orientation as the most favorable in which the guest molecule is totally embedded in the hydrophobic cavity of the cyclodextrin with the NO2 group located near the primary hydroxyls of the β-CD and the NH2 group near the secondary hydroxyls with no hydrogen bonding formation. The negative complexation and interaction energies calculated suggest that the inclusion complexes are stable. HOMO and LUMO orbital investigations confirm the better stability of the A orientation.Item Molecular modeling investigation of para-nitrobenzoic acid interaction in β-cyclodextrin(2011) Leila Nouar; Sakina Haiahem; Abdelazize Bouhadiba; Fatiha Madi; Leila LagrateGeometry optimizations of para-nitrobenzoic acid (PNBA)/β-cyclodextrin complex were carried out using MM+, PM3 and density function theory B3LYP/6-31G*. Calculations were performed upon the inclusion complexation of β-cyclodextrin (CD) with neutral (PNBA1) and anionic (PNBA2) species of para-nitrobenzoic acid. The results obtained from both methods consistently indicate that the complex of PNBA2/β-CD (B) is significantly more favorable than the others energetically. The negative enthalpy changes calculated from the statistical thermodynamic calculation suggest that both the inclusion complexation is favored enthalpy-driven process. The geometry of the most stable complex shows that the aromatic ring is deeply self-included inside the hydrophobic cavity of β-CD and also intermolecular hydrogen bonds were established between host and guest molecules. This suggests that hydrophobic effect and hydrogen bond play an important role in the complexation process.Item Theoretical study of inclusion complexation of 3-amino-5-nitrobenzisothiazole with β-cyclodextrin(2011) Leila Nouar; Sakina Haiahem; Abdelaziz Bouhadiba; Fatiha MadiThe inclusion process involving β-cyclodextrin (β-CD) and 3-amino-5-nitrobenzisothiazole (ANBT) has been investigated by using the MM+ force field, AM1, PM3, HF and B3LYP theories. In this study we took into account only the stochiometry1:1. The complexation and interaction energies for both orientations considered in this research are reported. All quantum computational methods gave the A orientation as the most favorable in which the guest molecule is totally embedded in the hydrophobic cavity of the cyclodextrin with the NO2 group located near the primary hydroxyls of the β-CD and the NH2 group near the secondary hydroxyls with no hydrogen bonding formation. The negative complexation and interaction energies calculated suggest that the inclusion complexes are stable. HOMO and LUMO orbital investigations confirm the better stability of the A orientation.Item Theoretical study of the inclusion processes of the phenylurea herbicide metobromuron in β-cyclodextrin.(ANSInet, Asian Network for Scientific Information, 2011) Leila Nouar; Sakina Haiahem; Abdelaziz Bouhadiba; Fatiha Madi; Leila Largate; Fateh DjeblouneWe investigated the inclusion process of phenylurea herbicide metobromuron (MB) in beta cyclodextrin (β-CD) with 1:1 stoichiometry using: (1) MM+ force field of molecular mechanics in order to research the lowest energy structure of the inclusion complex. (2) Superior levels of calculations were made such PM3, B3LYP/6-31G*, HF/6-31G* and ONIOM2 methods in order to approach the ideal geometry and provide further insight into the different complexation properties of the guest molecule. The data suggest that: The B orientation is significantly more favourable than the A orientation by an energy difference of 1.02 kcal mol-1 according to PM3 calculations. The geometry of the most stable complex shows that the aromatic ring is deeply self-included inside the hydrophobic cavity of β-CD also an intermolecular hydrogen bond is established between host and guest molecules. The formation of the inclusion complex is predicted to be an enthalpy-driven process in gas phase which is in accord with the experimental results. The statistical thermodynamic calculations by PM3 demonstrate that 1:1 MB/β-CD complex is favored by a negative enthalpy change.Item Structural Reliability Improvement Using In-Service Inspection for Intergranular Stress Corrosion of Large Stainless Steel Piping(InTech, 2012) A. Guedri; Y. Djebbar; Moe. Khaleel; A. ZeghloulThis paper describes probabilistic calculations that address Intergranular Stress Corrosion Cracking (IGSCC) of large stainless steel piping, a degradation mechanism of major concern to nuclear pressure boundary integrity. The first objective was to simulate the cracking of stainless steel piping under IGSCC conditions using the general methodology rec¬ommended in the modified computer program Piping Reliability Analysis Including Seismic Events (pc-PRAISE), and to characterize IGSCC by a single damage parameter (Dσ). This parameter, depends on residual stresses, environment conditions, and degree of sensitization. The second objective is to evaluate the structural reliability using remedial actions for IGSCC which are limited to benefits of in-service inspections and to identify the most effective approaches to improving piping reliability.Item Analyse expérimentale et analytique du comportement en flexion des poutres en béton armé préfissurées renforcées par un matériau composite en toile de fibres de carbone (TFC)(Revue synthèse université Badji Mokhtar Annaba, 2012) Sihem Kermiche; Redjel BachirCe travail constitue une contribution à l’analyse du comportement des poutres renforcées par des matériaux composites. L’analyse a été faite par une étude expérimentale et analytique sur onze éléments en béton et en béton armé sous et moyennement armés, préfissurés puis renforcés par du tissu en fibre de carbone collé in situ à l’aide d’une résine époxy. Afin d’étudier l’influence de l’état de fissuration initiale sur le comportement, l’une des poutres a été renforcée sans qu’elle ne soit préfissurée et a été comparée à une poutre préfissurée et renforcée puis à une autre chargée jusqu’à la rupture sans être préfissurée ni renforcée. Dans cette étude quatre poutres ont été préfissurées et renforcées dans leur partie tendue et sur la partie latérale avec des bandes en forme de U de différentes dimensions dans le but d’éviter le décollement d’une part et d’étudier la reprise du composite à l’effet du cisaillement d’autre part. Enfin, une étude comparative a été menée entre les résistances ultimes mesurées expérimentalement et celles calculées par les modèles analytiquesItem Influence of ethanol in the presence of H2 on the catalytic growth of vertically aligned carbon nanotubes(Appl. Catal. A: Gen., 2012) O. Guellati, I. Janowska, D. Bégin, M. Guerioune, Z. Mekhalif, J. Delhalle, S. Moldovan, O. Ersen and C. Pham-HuuThe vertically aligned multi-walled carbon nanotubes (VA-MWNTs) were synthesized by a catalytic chemical vapor deposition (CCVD) technique, using ferrocene as an iron catalyst precursor and toluene/ethanol mixture with different ratio as a carbon source/etching agent, in the presence of H2. The growth rate, efficiency and the structure of the synthesized tubes were investigated. The CNTs growth rate and quality of tubes significantly improve up to 9 vol.% of ethanol whereas a negative influence was observed for higher ethanol concentration (>17 vol.%). Low ethanol content in the reaction mixture (5 vol.%) results in the highest volume density of the tubes within the array along with highest specific surface area. The synergetic effect of EtOH/hydrogen on the growth rate of VA-MWNTs was observed as well.Item Theoretical investigation study based on PM3MM and ONIOM2 calculations of β-Cyclodextrin complexes with diphenylamine(2012) Abdelaziz Bouhadiba; Leila Nouar; Sakina Haiahem; Imene Djilani; Fatiha Madi; DjamelEddine KhatmiThe inclusion complex of b-cyclodextrin (b-CD) and diphenylamine (DPA) was investigated by using PM3MM, DFT, HF and ONIOM2 methods. The most stable structure was obtained at the optimum position and angle. The results indicate that the inclusion complex formed by DPA entering into the cavity of b-CD from its wide side (the secondary hydroxyl group side) is more stable than that formed by DPA entering into the cavity of b-CD from its narrow side (the primary hydroxyl group side). The structures show the presence of several intermolecular hydrogen bond interactions that were studied on the basis of natural bonding orbital (NBO) analysis, employed to quantify the donor–acceptor interactions between diphenylamine and b-CD. A study of these complexes in solution was carried out using the CPCM model to examine the influence of solvation on the stability of the diphenylamine b-CD complex.Item Molecular docking study on b-cyclodextrin Interactions of metobromuron and [3-(p-bromophenyl)-1-methoxy-1- methylurea](2012-03-04) sakina haiahem; Abdelaziz Bouhadiba; Leila Nouar; Imene Djilani; Fatiha Madi; Djamel Eddine KhatmiThe inclusion process involving b-cyclodextrin (b-cyclodextrin-CD) and phenylurea herbicide metobromuron (MB) has been investigated by using the MM?, PM3, B3LYP, HF, ONIOM2 and NBO methods. The binding and complexation energies for both orientations considered in this research are reported. The geometry of the most stable complex shows that the aromatic ring is deeply selfincluded inside the hydrophobic cavity of b-CD also an intermolecular hydrogen bond is established between hostand guest molecules. This suggests that hydrophobic effect and hydrogen bond play an important role in the complexation process. The statistical thermodynamic calculations by PM3 demonstrate that 1:1 MB/b-CD complex is favored by a negative enthalpy change. Moreover, NBO calculations proved also that are a very useful means to quantify the interaction energies of the hydrogen bonds.Item Inclusion complexes of ortho-anisidine and b-cyclodextrin: A quantum mechanical calculation(2013) Imene Djilani; Leila Nouar; Fatiha Madi; Sakina Haiahem; Abdelaziz Bouhadiba; DjamelEddine KhatmiThe structural aspects for the complexation of ortho-anisidine (O-AN)/b-cyclodextrin were explored by using PM6, density function theory B3LYP/6-31G*, M05-2X/6-31G*, B3PW91/6-31G*, MPW1PW91/6-31G*, HF/6-31G* methods and several combinations of ONIOM2 hybrid calculations. Calculations were performed upon the inclusion complexation of b-cyclodextrin (b-CD) with neutral (O-AN1) and cationic (O-AN2) species of ortho-anisidine. The obtained results with PM6 method clearly indicate that the formed complexes are energetically favored, the complex of O-AN2/b-CD in B orientation is significantly more favorable than the others energetically. The structures show the presence of several intermolecular hydrogen bond interactions that were studied on the basis of natural bonding orbital (NBO) analysis, employed to quantify the donor–acceptor interactions between ortho-anisidine and b-CD.Item Host-guest inclusion complex between b-cyclodextrin and paeonol: A theoretical approach(2013) Sakina Haiahem; Leila Nouar; Imen Djilani; Abdelazize Bouhadiba; Fatiha Madi; Djamel Eddine KhatmiHost-guest interactions of b-cyclodextrin (b-CD) with paeonol (PAE) were simulated using semi-empirical PM3 and both ONIOM2 [(B3LYP/6-31G*:PM3), (HF/6-31G*:PM3)] methods. The results obtained with PM3 method clearly indicate that the complexes formed are energetically favored with or without solvent, the model 1 (PAE entering into the cavity of b-CD from its wide side by OCH3 group) is found more favored than the model 2 (PAE entering into the cavity of b-CD from its wide side by COCH3 group). Finally, natural bonding orbital (NBO) analysis was performed based on ONIOM2 optimized complexes to quantify the donor–acceptor interactions between PAE and b-CD.Item Analysis and Characterization of PEMFC Power Systems with Bond Graph(2013-11) Nedjem Eddine Benchouia; Elias Hadjadj Aoual; Lakhdar Khochemane; Bouziane.MahmahThis paper addresses the problem of bond graph methodology as a graphical approach for modeling fuel cell systems. The system consists of a Proton Exchange Membrane Fuel Cell (PEMFC) stack and an interleaved boost converter. Simulation results illustrate the simplified system response obtained using the implementation of the governing equations in MATLAB/Simulink or a bond graphItem Synthesis and characterization of HDPE/N-MWNT nanocomposite films(Nanoscale Research Letters (NRL), 2014) F. Chouit, O. Guellati, S. Boukhzar, A. Harat, M. Guerioune and N. BadiIn this work, a series of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) with several weight percentages (0.1, 0.4, 0.8, and 1.0 wt.%) were synthesized by catalytic chemical vapor deposition (CCVD) technique. The N-MWCNTs were first characterized and then dispersed in high-density polyethylene (HDPE) polymer matrix to form a nanocomposite. The HDPE/N-MWCNT nanocomposite films were prepared by melt mixing and hot pressing; a good dispersion in the matrix and a good N-MWCNT-polymer interfacial adhesion have been verified by scanning electron microscopy (SEM). Raman spectroscopy measurements have been performed on prepared samples to confirm the presence and nature of N-MWNTs in HDPE matrix. The X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of HDPE matrix was not affected by the incorporation of the N-MWNTs.Item Device Electromagnetic Characterization of GaAs MESFET Transistor(2014) Houda Amri; Mourad ZaabatIn this paper, an electromagnetic study of MESFET transistor based on iterative method is presented. This method is generating the relationship between the incident and reflected waves from the planar circuits. The WCIP method is developed from the fast modal transform algorithm.Item Bond graph modeling approach development for fuel cell PEMFC systems(www.elsevier.com/locate/he, 2014-09-14) Nedjem Eddine Benchouia; Elias Hadjadj Aoul; Lakhdar Khochemane; Bouziane MahmahThis paper addresses the problem of bond graph methodology as a graphical approach for modeling fuel cell systems. The system consists of a Proton Exchange Membrane Fuel Cell (PEMFC) stack, an interleaved boost converter, battery pack connected via a buck converter. Simulation results illustrate the simplified system response obtained using implementation of the governing equations in MATLAB/Simulink and is compared with a bond graph implementation in the simulation program 20-sim.